Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 3486 insertions, 0 deletions

diff --git a/sound/oss/vwsnd.c b/sound/oss/vwsnd.c
new file mode 100644
index 00000000000..265423054ca
--- /dev/null
+++ b/sound/oss/vwsnd.c
@@ -0,0 +1,3486 @@
+/*
+ * Sound driver for Silicon Graphics 320 and 540 Visual Workstations'
+ * onboard audio.  See notes in Documentation/sound/oss/vwsnd .
+ *
+ * Copyright 1999 Silicon Graphics, Inc.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#undef VWSND_DEBUG			/* define for debugging */
+
+/*
+ * XXX to do -
+ *
+ *	External sync.
+ *	Rename swbuf, hwbuf, u&i, hwptr&swptr to something rational.
+ *	Bug - if select() called before read(), pcm_setup() not called.
+ *	Bug - output doesn't stop soon enough if process killed.
+ */
+
+/*
+ * Things to test -
+ *
+ *	Will readv/writev work?  Write a test.
+ *
+ *	insmod/rmmod 100 million times.
+ *
+ *	Run I/O until int ptrs wrap around (roughly 6.2 hours @ DAT
+ *	rate).
+ *
+ *	Concurrent threads banging on mixer simultaneously, both UP
+ *	and SMP kernels.  Especially, watch for thread A changing
+ *	OUTSRC while thread B changes gain -- both write to the same
+ *	ad1843 register.
+ *
+ *	What happens if a client opens /dev/audio then forks?
+ *	Do two procs have /dev/audio open?  Test.
+ *
+ *	Pump audio through the CD, MIC and line inputs and verify that
+ *	they mix/mute into the output.
+ *
+ *	Apps:
+ *		amp
+ *		mpg123
+ *		x11amp
+ *		mxv
+ *		kmedia
+ *		esound
+ *		need more input apps
+ *
+ *	Run tests while bombarding with signals.  setitimer(2) will do it...  */
+
+/*
+ * This driver is organized in nine sections.
+ * The nine sections are:
+ *
+ *	debug stuff
+ * 	low level lithium access
+ *	high level lithium access
+ *	AD1843 access
+ *	PCM I/O
+ *	audio driver
+ *	mixer driver
+ *	probe/attach/unload
+ *	initialization and loadable kernel module interface
+ *
+ * That is roughly the order of increasing abstraction, so forward
+ * dependencies are minimal.
+ */
+
+/*
+ * Locking Notes
+ *
+ *	INC_USE_COUNT and DEC_USE_COUNT keep track of the number of
+ *	open descriptors to this driver. They store it in vwsnd_use_count.
+ * 	The global device list, vwsnd_dev_list,	is immutable when the IN_USE
+ *	is true.
+ *
+ *	devc->open_lock is a semaphore that is used to enforce the
+ *	single reader/single writer rule for /dev/audio.  The rule is
+ *	that each device may have at most one reader and one writer.
+ *	Open will block until the previous client has closed the
+ *	device, unless O_NONBLOCK is specified.
+ *
+ *	The semaphore devc->io_sema serializes PCM I/O syscalls.  This
+ *	is unnecessary in Linux 2.2, because the kernel lock
+ *	serializes read, write, and ioctl globally, but it's there,
+ *	ready for the brave, new post-kernel-lock world.
+ *
+ *	Locking between interrupt and baselevel is handled by the
+ *	"lock" spinlock in vwsnd_port (one lock each for read and
+ *	write).  Each half holds the lock just long enough to see what
+ *	area it owns and update its pointers.  See pcm_output() and
+ *	pcm_input() for most of the gory stuff.
+ *
+ *	devc->mix_sema serializes all mixer ioctls.  This is also
+ *	redundant because of the kernel lock.
+ *
+ *	The lowest level lock is lith->lithium_lock.  It is a
+ *	spinlock which is held during the two-register tango of
+ *	reading/writing an AD1843 register.  See
+ *	li_{read,write}_ad1843_reg().
+ */
+
+/*
+ * Sample Format Notes
+ *
+ *	Lithium's DMA engine has two formats: 16-bit 2's complement
+ *	and 8-bit unsigned .  16-bit transfers the data unmodified, 2
+ *	bytes per sample.  8-bit unsigned transfers 1 byte per sample
+ *	and XORs each byte with 0x80.  Lithium can input or output
+ *	either mono or stereo in either format.
+ *
+ *	The AD1843 has four formats: 16-bit 2's complement, 8-bit
+ *	unsigned, 8-bit mu-Law and 8-bit A-Law.
+ *
+ *	This driver supports five formats: AFMT_S8, AFMT_U8,
+ *	AFMT_MU_LAW, AFMT_A_LAW, and AFMT_S16_LE.
+ *
+ *	For AFMT_U8 output, we keep the AD1843 in 16-bit mode, and
+ *	rely on Lithium's XOR to translate between U8 and S8.
+ *
+ *	For AFMT_S8, AFMT_MU_LAW and AFMT_A_LAW output, we have to XOR
+ *	the 0x80 bit in software to compensate for Lithium's XOR.
+ *	This happens in pcm_copy_{in,out}().
+ *
+ * Changes:
+ * 11-10-2000	Bartlomiej Zolnierkiewicz <bkz@linux-ide.org>
+ *		Added some __init/__exit
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+
+#include <linux/spinlock.h>
+#include <linux/smp_lock.h>
+#include <linux/wait.h>
+#include <linux/interrupt.h>
+#include <asm/semaphore.h>
+#include <asm/mach-visws/cobalt.h>
+
+#include "sound_config.h"
+
+/*****************************************************************************/
+/* debug stuff */
+
+#ifdef VWSND_DEBUG
+
+static int shut_up = 1;
+
+/*
+ * dbgassert - called when an assertion fails.
+ */
+
+static void dbgassert(const char *fcn, int line, const char *expr)
+{
+	if (in_interrupt())
+		panic("ASSERTION FAILED IN INTERRUPT, %s:%s:%d %s\n",
+		      __FILE__, fcn, line, expr);
+	else {
+		int x;
+		printk(KERN_ERR "ASSERTION FAILED, %s:%s:%d %s\n",
+		       __FILE__, fcn, line, expr);
+		x = * (volatile int *) 0; /* force proc to exit */
+	}
+}
+
+/*
+ * Bunch of useful debug macros:
+ *
+ *	ASSERT	- print unless e nonzero (panic if in interrupt)
+ *	DBGDO	- include arbitrary code if debugging
+ *	DBGX	- debug print raw (w/o function name)
+ *	DBGP	- debug print w/ function name
+ *	DBGE	- debug print function entry
+ *	DBGC	- debug print function call
+ *	DBGR	- debug print function return
+ *	DBGXV	- debug print raw when verbose
+ *	DBGPV	- debug print when verbose
+ *	DBGEV	- debug print function entry when verbose
+ *	DBGRV	- debug print function return when verbose
+ */
+
+#define ASSERT(e)      ((e) ? (void) 0 : dbgassert(__FUNCTION__, __LINE__, #e))
+#define DBGDO(x)            x
+#define DBGX(fmt, args...)  (in_interrupt() ? 0 : printk(KERN_ERR fmt, ##args))
+#define DBGP(fmt, args...)  (DBGX("%s: " fmt, __FUNCTION__ , ##args))
+#define DBGE(fmt, args...)  (DBGX("%s" fmt, __FUNCTION__ , ##args))
+#define DBGC(rtn)           (DBGP("calling %s\n", rtn))
+#define DBGR()              (DBGP("returning\n"))
+#define DBGXV(fmt, args...) (shut_up ? 0 : DBGX(fmt, ##args))
+#define DBGPV(fmt, args...) (shut_up ? 0 : DBGP(fmt, ##args))
+#define DBGEV(fmt, args...) (shut_up ? 0 : DBGE(fmt, ##args))
+#define DBGCV(rtn)          (shut_up ? 0 : DBGC(rtn))
+#define DBGRV()             (shut_up ? 0 : DBGR())
+
+#else /* !VWSND_DEBUG */
+
+#define ASSERT(e)           ((void) 0)
+#define DBGDO(x)            /* don't */
+#define DBGX(fmt, args...)  ((void) 0)
+#define DBGP(fmt, args...)  ((void) 0)
+#define DBGE(fmt, args...)  ((void) 0)
+#define DBGC(rtn)           ((void) 0)
+#define DBGR()              ((void) 0)
+#define DBGPV(fmt, args...) ((void) 0)
+#define DBGXV(fmt, args...) ((void) 0)
+#define DBGEV(fmt, args...) ((void) 0)
+#define DBGCV(rtn)          ((void) 0)
+#define DBGRV()             ((void) 0)
+
+#endif /* !VWSND_DEBUG */
+
+/*****************************************************************************/
+/* low level lithium access */
+
+/*
+ * We need to talk to Lithium registers on three pages.  Here are
+ * the pages' offsets from the base address (0xFF001000).
+ */
+
+enum {
+	LI_PAGE0_OFFSET = 0x01000 - 0x1000, /* FF001000 */
+	LI_PAGE1_OFFSET = 0x0F000 - 0x1000, /* FF00F000 */
+	LI_PAGE2_OFFSET = 0x10000 - 0x1000, /* FF010000 */
+};
+
+/* low-level lithium data */
+
+typedef struct lithium {
+	void *		page0;		/* virtual addresses */
+	void *		page1;
+	void *		page2;
+	spinlock_t	lock;		/* protects codec and UST/MSC access */
+} lithium_t;
+
+/*
+ * li_create initializes the lithium_t structure and sets up vm mappings
+ * to access the registers.
+ * Returns 0 on success, -errno on failure.
+ */
+
+static int __init li_create(lithium_t *lith, unsigned long baseaddr)
+{
+	static void li_destroy(lithium_t *);
+
+	spin_lock_init(&lith->lock);
+	lith->page0 = ioremap_nocache(baseaddr + LI_PAGE0_OFFSET, PAGE_SIZE);
+	lith->page1 = ioremap_nocache(baseaddr + LI_PAGE1_OFFSET, PAGE_SIZE);
+	lith->page2 = ioremap_nocache(baseaddr + LI_PAGE2_OFFSET, PAGE_SIZE);
+	if (!lith->page0 || !lith->page1 || !lith->page2) {
+		li_destroy(lith);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+/*
+ * li_destroy destroys the lithium_t structure and vm mappings.
+ */
+
+static void li_destroy(lithium_t *lith)
+{
+	if (lith->page0) {
+		iounmap(lith->page0);
+		lith->page0 = NULL;
+	}
+	if (lith->page1) {
+		iounmap(lith->page1);
+		lith->page1 = NULL;
+	}
+	if (lith->page2) {
+		iounmap(lith->page2);
+		lith->page2 = NULL;
+	}
+}
+
+/*
+ * basic register accessors - read/write long/byte
+ */
+
+static __inline__ unsigned long li_readl(lithium_t *lith, int off)
+{
+	return * (volatile unsigned long *) (lith->page0 + off);
+}
+
+static __inline__ unsigned char li_readb(lithium_t *lith, int off)
+{
+	return * (volatile unsigned char *) (lith->page0 + off);
+}
+
+static __inline__ void li_writel(lithium_t *lith, int off, unsigned long val)
+{
+	* (volatile unsigned long *) (lith->page0 + off) = val;
+}
+
+static __inline__ void li_writeb(lithium_t *lith, int off, unsigned char val)
+{
+	* (volatile unsigned char *) (lith->page0 + off) = val;
+}
+
+/*****************************************************************************/
+/* High Level Lithium Access */
+
+/*
+ * Lithium DMA Notes
+ *
+ * Lithium has two dedicated DMA channels for audio.  They are known
+ * as comm1 and comm2 (communication areas 1 and 2).  Comm1 is for
+ * input, and comm2 is for output.  Each is controlled by three
+ * registers: BASE (base address), CFG (config) and CCTL
+ * (config/control).
+ *
+ * Each DMA channel points to a physically contiguous ring buffer in
+ * main memory of up to 8 Kbytes.  (This driver always uses 8 Kb.)
+ * There are three pointers into the ring buffer: read, write, and
+ * trigger.  The pointers are 8 bits each.  Each pointer points to
+ * 32-byte "chunks" of data.  The DMA engine moves 32 bytes at a time,
+ * so there is no finer-granularity control.
+ *
+ * In comm1, the hardware updates the write ptr, and software updates
+ * the read ptr.  In comm2, it's the opposite: hardware updates the
+ * read ptr, and software updates the write ptr.  I designate the
+ * hardware-updated ptr as the hwptr, and the software-updated ptr as
+ * the swptr.
+ *
+ * The trigger ptr and trigger mask are used to trigger interrupts.
+ * From the Lithium spec, section 5.6.8, revision of 12/15/1998:
+ *
+ *	Trigger Mask Value
+ *
+ *	A three bit wide field that represents a power of two mask
+ *	that is used whenever the trigger pointer is compared to its
+ *	respective read or write pointer.  A value of zero here
+ *	implies a mask of 0xFF and a value of seven implies a mask
+ *	0x01.  This value can be used to sub-divide the ring buffer
+ *	into pie sections so that interrupts monitor the progress of
+ *	hardware from section to section.
+ *
+ * My interpretation of that is, whenever the hw ptr is updated, it is
+ * compared with the trigger ptr, and the result is masked by the
+ * trigger mask.  (Actually, by the complement of the trigger mask.)
+ * If the result is zero, an interrupt is triggered.  I.e., interrupt
+ * if ((hwptr & ~mask) == (trptr & ~mask)).  The mask is formed from
+ * the trigger register value as mask = (1 << (8 - tmreg)) - 1.
+ *
+ * In yet different words, setting tmreg to 0 causes an interrupt after
+ * every 256 DMA chunks (8192 bytes) or once per traversal of the
+ * ring buffer.  Setting it to 7 caues an interrupt every 2 DMA chunks
+ * (64 bytes) or 128 times per traversal of the ring buffer.
+ */
+
+/* Lithium register offsets and bit definitions */
+
+#define LI_HOST_CONTROLLER	0x000
+# define LI_HC_RESET		 0x00008000
+# define LI_HC_LINK_ENABLE	 0x00004000
+# define LI_HC_LINK_FAILURE	 0x00000004
+# define LI_HC_LINK_CODEC	 0x00000002
+# define LI_HC_LINK_READY	 0x00000001
+
+#define LI_INTR_STATUS		0x010
+#define LI_INTR_MASK		0x014
+# define LI_INTR_LINK_ERR	 0x00008000
+# define LI_INTR_COMM2_TRIG	 0x00000008
+# define LI_INTR_COMM2_UNDERFLOW 0x00000004
+# define LI_INTR_COMM1_TRIG	 0x00000002
+# define LI_INTR_COMM1_OVERFLOW  0x00000001
+
+#define LI_CODEC_COMMAND	0x018
+# define LI_CC_BUSY		 0x00008000
+# define LI_CC_DIR		 0x00000080
+#  define LI_CC_DIR_RD		  LI_CC_DIR
+#  define LI_CC_DIR_WR		(!LI_CC_DIR)
+# define LI_CC_ADDR_MASK	 0x0000007F
+
+#define LI_CODEC_DATA		0x01C
+
+#define LI_COMM1_BASE		0x100
+#define LI_COMM1_CTL		0x104
+# define LI_CCTL_RESET		 0x80000000
+# define LI_CCTL_SIZE		 0x70000000
+# define LI_CCTL_DMA_ENABLE	 0x08000000
+# define LI_CCTL_TMASK		 0x07000000 /* trigger mask */
+# define LI_CCTL_TPTR		 0x00FF0000 /* trigger pointer */
+# define LI_CCTL_RPTR		 0x0000FF00
+# define LI_CCTL_WPTR		 0x000000FF
+#define LI_COMM1_CFG		0x108
+# define LI_CCFG_LOCK		 0x00008000
+# define LI_CCFG_SLOT		 0x00000070
+# define LI_CCFG_DIRECTION	 0x00000008
+#  define LI_CCFG_DIR_IN	(!LI_CCFG_DIRECTION)
+#  define LI_CCFG_DIR_OUT	  LI_CCFG_DIRECTION
+# define LI_CCFG_MODE		 0x00000004
+#  define LI_CCFG_MODE_MONO	(!LI_CCFG_MODE)
+#  define LI_CCFG_MODE_STEREO	  LI_CCFG_MODE
+# define LI_CCFG_FORMAT		 0x00000003
+#  define LI_CCFG_FMT_8BIT	  0x00000000
+#  define LI_CCFG_FMT_16BIT	  0x00000001
+#define LI_COMM2_BASE		0x10C
+#define LI_COMM2_CTL		0x110
+ /* bit definitions are the same as LI_COMM1_CTL */
+#define LI_COMM2_CFG		0x114
+ /* bit definitions are the same as LI_COMM1_CFG */
+
+#define LI_UST_LOW		0x200	/* 64-bit Unadjusted System Time is */
+#define LI_UST_HIGH		0x204	/* microseconds since boot */
+
+#define LI_AUDIO1_UST		0x300	/* UST-MSC pairs */
+#define LI_AUDIO1_MSC		0x304	/* MSC (Media Stream Counter) */
+#define LI_AUDIO2_UST		0x308	/* counts samples actually */
+#define LI_AUDIO2_MSC		0x30C	/* processed as of time UST */
+
+/* 
+ * Lithium's DMA engine operates on chunks of 32 bytes.  We call that
+ * a DMACHUNK.
+ */
+
+#define DMACHUNK_SHIFT 5
+#define DMACHUNK_SIZE (1 << DMACHUNK_SHIFT)
+#define BYTES_TO_CHUNKS(bytes) ((bytes) >> DMACHUNK_SHIFT)
+#define CHUNKS_TO_BYTES(chunks) ((chunks) << DMACHUNK_SHIFT)
+
+/*
+ * Two convenient macros to shift bitfields into/out of position.
+ *
+ * Observe that (mask & -mask) is (1 << low_set_bit_of(mask)).
+ * As long as mask is constant, we trust the compiler will change the
+ * multipy and divide into shifts.
+ */
+
+#define SHIFT_FIELD(val, mask) (((val) * ((mask) & -(mask))) & (mask))
+#define UNSHIFT_FIELD(val, mask) (((val) & (mask)) / ((mask) & -(mask)))
+
+/*
+ * dma_chan_desc is invariant information about a Lithium
+ * DMA channel.  There are two instances, li_comm1 and li_comm2.
+ *
+ * Note that the CCTL register fields are write ptr and read ptr, but what
+ * we care about are which pointer is updated by software and which by
+ * hardware.
+ */
+
+typedef struct dma_chan_desc {
+	int basereg;
+	int cfgreg;
+	int ctlreg;
+	int hwptrreg;
+	int swptrreg;
+	int ustreg;
+	int mscreg;
+	unsigned long swptrmask;
+	int ad1843_slot;
+	int direction;			/* LI_CCTL_DIR_IN/OUT */
+} dma_chan_desc_t;
+
+static const dma_chan_desc_t li_comm1 = {
+	LI_COMM1_BASE,			/* base register offset */
+	LI_COMM1_CFG,			/* config register offset */
+	LI_COMM1_CTL,			/* control register offset */
+	LI_COMM1_CTL + 0,		/* hw ptr reg offset (write ptr) */
+	LI_COMM1_CTL + 1,		/* sw ptr reg offset (read ptr) */
+	LI_AUDIO1_UST,			/* ust reg offset */
+	LI_AUDIO1_MSC,			/* msc reg offset */
+	LI_CCTL_RPTR,			/* sw ptr bitmask in ctlval */
+	2,				/* ad1843 serial slot */
+	LI_CCFG_DIR_IN			/* direction */
+};
+
+static const dma_chan_desc_t li_comm2 = {
+	LI_COMM2_BASE,			/* base register offset */
+	LI_COMM2_CFG,			/* config register offset */
+	LI_COMM2_CTL,			/* control register offset */
+	LI_COMM2_CTL + 1,		/* hw ptr reg offset (read ptr) */
+	LI_COMM2_CTL + 0,		/* sw ptr reg offset (writr ptr) */
+	LI_AUDIO2_UST,			/* ust reg offset */
+	LI_AUDIO2_MSC,			/* msc reg offset */
+	LI_CCTL_WPTR,			/* sw ptr bitmask in ctlval */
+	2,				/* ad1843 serial slot */
+	LI_CCFG_DIR_OUT			/* direction */
+};
+
+/*
+ * dma_chan is variable information about a Lithium DMA channel.
+ *
+ * The desc field points to invariant information.
+ * The lith field points to a lithium_t which is passed
+ * to li_read* and li_write* to access the registers.
+ * The *val fields shadow the lithium registers' contents.
+ */
+
+typedef struct dma_chan {
+	const dma_chan_desc_t *desc;
+	lithium_t      *lith;
+	unsigned long   baseval;
+	unsigned long	cfgval;
+	unsigned long	ctlval;
+} dma_chan_t;
+
+/*
+ * ustmsc is a UST/MSC pair (Unadjusted System Time/Media Stream Counter).
+ * UST is time in microseconds since the system booted, and MSC is a
+ * counter that increments with every audio sample.
+ */
+
+typedef struct ustmsc {
+	unsigned long long ust;
+	unsigned long msc;
+} ustmsc_t;
+
+/*
+ * li_ad1843_wait waits until lithium says the AD1843 register
+ * exchange is not busy.  Returns 0 on success, -EBUSY on timeout.
+ *
+ * Locking: must be called with lithium_lock held.
+ */
+
+static int li_ad1843_wait(lithium_t *lith)
+{
+	unsigned long later = jiffies + 2;
+	while (li_readl(lith, LI_CODEC_COMMAND) & LI_CC_BUSY)
+		if (time_after_eq(jiffies, later))
+			return -EBUSY;
+	return 0;
+}
+
+/*
+ * li_read_ad1843_reg returns the current contents of a 16 bit AD1843 register.
+ *
+ * Returns unsigned register value on success, -errno on failure.
+ */
+
+static int li_read_ad1843_reg(lithium_t *lith, int reg)
+{
+	int val;
+
+	ASSERT(!in_interrupt());
+	spin_lock(&lith->lock);
+	{
+		val = li_ad1843_wait(lith);
+		if (val == 0) {
+			li_writel(lith, LI_CODEC_COMMAND, LI_CC_DIR_RD | reg);
+			val = li_ad1843_wait(lith);
+		}
+		if (val == 0)
+			val = li_readl(lith, LI_CODEC_DATA);
+	}
+	spin_unlock(&lith->lock);
+
+	DBGXV("li_read_ad1843_reg(lith=0x%p, reg=%d) returns 0x%04x\n",
+	      lith, reg, val);
+
+	return val;
+}
+
+/*
+ * li_write_ad1843_reg writes the specified value to a 16 bit AD1843 register.
+ */
+
+static void li_write_ad1843_reg(lithium_t *lith, int reg, int newval)
+{
+	spin_lock(&lith->lock);
+	{
+		if (li_ad1843_wait(lith) == 0) {
+			li_writel(lith, LI_CODEC_DATA, newval);
+			li_writel(lith, LI_CODEC_COMMAND, LI_CC_DIR_WR | reg);
+		}
+	}
+	spin_unlock(&lith->lock);
+}
+
+/*
+ * li_setup_dma calculates all the register settings for DMA in a particular
+ * mode.  It takes too many arguments.
+ */
+
+static void li_setup_dma(dma_chan_t *chan,
+			 const dma_chan_desc_t *desc,
+			 lithium_t *lith,
+			 unsigned long buffer_paddr,
+			 int bufshift,
+			 int fragshift,
+			 int channels,
+			 int sampsize)
+{
+	unsigned long mode, format;
+	unsigned long size, tmask;
+
+	DBGEV("(chan=0x%p, desc=0x%p, lith=0x%p, buffer_paddr=0x%lx, "
+	     "bufshift=%d, fragshift=%d, channels=%d, sampsize=%d)\n",
+	     chan, desc, lith, buffer_paddr,
+	     bufshift, fragshift, channels, sampsize);
+
+	/* Reset the channel first. */
+
+	li_writel(lith, desc->ctlreg, LI_CCTL_RESET);
+
+	ASSERT(channels == 1 || channels == 2);
+	if (channels == 2)
+		mode = LI_CCFG_MODE_STEREO;
+	else
+		mode = LI_CCFG_MODE_MONO;
+	ASSERT(sampsize == 1 || sampsize == 2);
+	if (sampsize == 2)
+		format = LI_CCFG_FMT_16BIT;
+	else
+		format = LI_CCFG_FMT_8BIT;
+	chan->desc = desc;
+	chan->lith = lith;
+
+	/*
+	 * Lithium DMA address register takes a 40-bit physical
+	 * address, right-shifted by 8 so it fits in 32 bits.  Bit 37
+	 * must be set -- it enables cache coherence.
+	 */
+
+	ASSERT(!(buffer_paddr & 0xFF));
+	chan->baseval = (buffer_paddr >> 8) | 1 << (37 - 8);
+
+	chan->cfgval = (!LI_CCFG_LOCK |
+			SHIFT_FIELD(desc->ad1843_slot, LI_CCFG_SLOT) |
+			desc->direction |
+			mode |
+			format);
+
+	size = bufshift - 6;
+	tmask = 13 - fragshift;		/* See Lithium DMA Notes above. */
+	ASSERT(size >= 2 && size <= 7);
+	ASSERT(tmask >= 1 && tmask <= 7);
+	chan->ctlval = (!LI_CCTL_RESET |
+			SHIFT_FIELD(size, LI_CCTL_SIZE) |
+			!LI_CCTL_DMA_ENABLE |
+			SHIFT_FIELD(tmask, LI_CCTL_TMASK) |
+			SHIFT_FIELD(0, LI_CCTL_TPTR));
+
+	DBGPV("basereg 0x%x = 0x%lx\n", desc->basereg, chan->baseval);
+	DBGPV("cfgreg 0x%x = 0x%lx\n", desc->cfgreg, chan->cfgval);
+	DBGPV("ctlreg 0x%x = 0x%lx\n", desc->ctlreg, chan->ctlval);
+
+	li_writel(lith, desc->basereg, chan->baseval);
+	li_writel(lith, desc->cfgreg, chan->cfgval);
+	li_writel(lith, desc->ctlreg, chan->ctlval);
+
+	DBGRV();
+}
+
+static void li_shutdown_dma(dma_chan_t *chan)
+{
+	lithium_t *lith = chan->lith;
+	void * lith1 = lith->page1;
+
+	DBGEV("(chan=0x%p)\n", chan);
+	
+	chan->ctlval &= ~LI_CCTL_DMA_ENABLE;
+	DBGPV("ctlreg 0x%x = 0x%lx\n", chan->desc->ctlreg, chan->ctlval);
+	li_writel(lith, chan->desc->ctlreg, chan->ctlval);
+
+	/*
+	 * Offset 0x500 on Lithium page 1 is an undocumented,
+	 * unsupported register that holds the zero sample value.
+	 * Lithium is supposed to output zero samples when DMA is
+	 * inactive, and repeat the last sample when DMA underflows.
+	 * But it has a bug, where, after underflow occurs, the zero
+	 * sample is not reset.
+	 *
+	 * I expect this to break in a future rev of Lithium.
+	 */
+
+	if (lith1 && chan->desc->direction == LI_CCFG_DIR_OUT)
+		* (volatile unsigned long *) (lith1 + 0x500) = 0;
+}
+
+/*
+ * li_activate_dma always starts dma at the beginning of the buffer.
+ *
+ * N.B., these may be called from interrupt.
+ */
+
+static __inline__ void li_activate_dma(dma_chan_t *chan)
+{
+	chan->ctlval |= LI_CCTL_DMA_ENABLE;
+	DBGPV("ctlval = 0x%lx\n", chan->ctlval);
+	li_writel(chan->lith, chan->desc->ctlreg, chan->ctlval);
+}
+
+static void li_deactivate_dma(dma_chan_t *chan)
+{
+	lithium_t *lith = chan->lith;
+	void * lith2 = lith->page2;
+
+	chan->ctlval &= ~(LI_CCTL_DMA_ENABLE | LI_CCTL_RPTR | LI_CCTL_WPTR);
+	DBGPV("ctlval = 0x%lx\n", chan->ctlval);
+	DBGPV("ctlreg 0x%x = 0x%lx\n", chan->desc->ctlreg, chan->ctlval);
+	li_writel(lith, chan->desc->ctlreg, chan->ctlval);
+
+	/*
+	 * Offsets 0x98 and 0x9C on Lithium page 2 are undocumented,
+	 * unsupported registers that are internal copies of the DMA
+	 * read and write pointers.  Because of a Lithium bug, these
+	 * registers aren't zeroed correctly when DMA is shut off.  So
+	 * we whack them directly.
+	 *
+	 * I expect this to break in a future rev of Lithium.
+	 */
+
+	if (lith2 && chan->desc->direction == LI_CCFG_DIR_OUT) {
+		* (volatile unsigned long *) (lith2 + 0x98) = 0;
+		* (volatile unsigned long *) (lith2 + 0x9C) = 0;
+	}
+}
+
+/*
+ * read/write the ring buffer pointers.  These routines' arguments and results
+ * are byte offsets from the beginning of the ring buffer.
+ */
+
+static __inline__ int li_read_swptr(dma_chan_t *chan)
+{
+	const unsigned long mask = chan->desc->swptrmask;
+
+	return CHUNKS_TO_BYTES(UNSHIFT_FIELD(chan->ctlval, mask));
+}
+
+static __inline__ int li_read_hwptr(dma_chan_t *chan)
+{
+	return CHUNKS_TO_BYTES(li_readb(chan->lith, chan->desc->hwptrreg));
+}
+
+static __inline__ void li_write_swptr(dma_chan_t *chan, int val)
+{
+	const unsigned long mask = chan->desc->swptrmask;
+
+	ASSERT(!(val & ~CHUNKS_TO_BYTES(0xFF)));
+	val = BYTES_TO_CHUNKS(val);
+	chan->ctlval = (chan->ctlval & ~mask) | SHIFT_FIELD(val, mask);
+	li_writeb(chan->lith, chan->desc->swptrreg, val);
+}
+
+/* li_read_USTMSC() returns a UST/MSC pair for the given channel. */
+
+static void li_read_USTMSC(dma_chan_t *chan, ustmsc_t *ustmsc)
+{
+	lithium_t *lith = chan->lith;
+	const dma_chan_desc_t *desc = chan->desc;
+	unsigned long now_low, now_high0, now_high1, chan_ust;
+
+	spin_lock(&lith->lock);
+	{
+		/*
+		 * retry until we do all five reads without the
+		 * high word changing.  (High word increments
+		 * every 2^32 microseconds, i.e., not often)
+		 */
+		do {
+			now_high0 = li_readl(lith, LI_UST_HIGH);
+			now_low = li_readl(lith, LI_UST_LOW);
+
+			/*
+			 * Lithium guarantees these two reads will be
+			 * atomic -- ust will not increment after msc
+			 * is read.
+			 */
+
+			ustmsc->msc = li_readl(lith, desc->mscreg);
+			chan_ust = li_readl(lith, desc->ustreg);
+
+			now_high1 = li_readl(lith, LI_UST_HIGH);
+		} while (now_high0 != now_high1);
+	}	
+	spin_unlock(&lith->lock);
+	ustmsc->ust = ((unsigned long long) now_high0 << 32 | chan_ust);
+}
+
+static void li_enable_interrupts(lithium_t *lith, unsigned int mask)
+{
+	DBGEV("(lith=0x%p, mask=0x%x)\n", lith, mask);
+
+	/* clear any already-pending interrupts. */
+
+	li_writel(lith, LI_INTR_STATUS, mask);
+
+	/* enable the interrupts. */
+
+	mask |= li_readl(lith, LI_INTR_MASK);
+	li_writel(lith, LI_INTR_MASK, mask);
+}
+
+static void li_disable_interrupts(lithium_t *lith, unsigned int mask)
+{
+	unsigned int keepmask;
+
+	DBGEV("(lith=0x%p, mask=0x%x)\n", lith, mask);
+
+	/* disable the interrupts */
+
+	keepmask = li_readl(lith, LI_INTR_MASK) & ~mask;
+	li_writel(lith, LI_INTR_MASK, keepmask);
+
+	/* clear any pending interrupts. */
+
+	li_writel(lith, LI_INTR_STATUS, mask);
+}
+
+/* Get the interrupt status and clear all pending interrupts. */
+
+static unsigned int li_get_clear_intr_status(lithium_t *lith)
+{
+	unsigned int status;
+
+	status = li_readl(lith, LI_INTR_STATUS);
+	li_writel(lith, LI_INTR_STATUS, ~0);
+	return status & li_readl(lith, LI_INTR_MASK);
+}
+
+static int li_init(lithium_t *lith)
+{
+	/* 1. System power supplies stabilize. */
+
+	/* 2. Assert the ~RESET signal. */
+
+	li_writel(lith, LI_HOST_CONTROLLER, LI_HC_RESET);
+	udelay(1);
+
+	/* 3. Deassert the ~RESET signal and enter a wait period to allow
+	   the AD1843 internal clocks and the external crystal oscillator
+	   to stabilize. */
+
+	li_writel(lith, LI_HOST_CONTROLLER, LI_HC_LINK_ENABLE);
+	udelay(1);
+
+	return 0;
+}
+
+/*****************************************************************************/
+/* AD1843 access */
+
+/*
+ * AD1843 bitfield definitions.  All are named as in the AD1843 data
+ * sheet, with ad1843_ prepended and individual bit numbers removed.
+ *
+ * E.g., bits LSS0 through LSS2 become ad1843_LSS.
+ *
+ * Only the bitfields we need are defined.
+ */
+
+typedef struct ad1843_bitfield {
+	char reg;
+	char lo_bit;
+	char nbits;
+} ad1843_bitfield_t;
+
+static const ad1843_bitfield_t
+	ad1843_PDNO   = {  0, 14,  1 },	/* Converter Power-Down Flag */
+	ad1843_INIT   = {  0, 15,  1 },	/* Clock Initialization Flag */
+	ad1843_RIG    = {  2,  0,  4 },	/* Right ADC Input Gain */
+	ad1843_RMGE   = {  2,  4,  1 },	/* Right ADC Mic Gain Enable */
+	ad1843_RSS    = {  2,  5,  3 },	/* Right ADC Source Select */
+	ad1843_LIG    = {  2,  8,  4 },	/* Left ADC Input Gain */
+	ad1843_LMGE   = {  2, 12,  1 },	/* Left ADC Mic Gain Enable */
+	ad1843_LSS    = {  2, 13,  3 },	/* Left ADC Source Select */
+	ad1843_RX1M   = {  4,  0,  5 },	/* Right Aux 1 Mix Gain/Atten */
+	ad1843_RX1MM  = {  4,  7,  1 },	/* Right Aux 1 Mix Mute */
+	ad1843_LX1M   = {  4,  8,  5 },	/* Left Aux 1 Mix Gain/Atten */
+	ad1843_LX1MM  = {  4, 15,  1 },	/* Left Aux 1 Mix Mute */
+	ad1843_RX2M   = {  5,  0,  5 },	/* Right Aux 2 Mix Gain/Atten */
+	ad1843_RX2MM  = {  5,  7,  1 },	/* Right Aux 2 Mix Mute */
+	ad1843_LX2M   = {  5,  8,  5 },	/* Left Aux 2 Mix Gain/Atten */
+	ad1843_LX2MM  = {  5, 15,  1 },	/* Left Aux 2 Mix Mute */
+	ad1843_RMCM   = {  7,  0,  5 },	/* Right Mic Mix Gain/Atten */
+	ad1843_RMCMM  = {  7,  7,  1 },	/* Right Mic Mix Mute */
+	ad1843_LMCM   = {  7,  8,  5 },	/* Left Mic Mix Gain/Atten */
+	ad1843_LMCMM  = {  7, 15,  1 },	/* Left Mic Mix Mute */
+	ad1843_HPOS   = {  8,  4,  1 },	/* Headphone Output Voltage Swing */
+	ad1843_HPOM   = {  8,  5,  1 },	/* Headphone Output Mute */
+	ad1843_RDA1G  = {  9,  0,  6 },	/* Right DAC1 Analog/Digital Gain */
+	ad1843_RDA1GM = {  9,  7,  1 },	/* Right DAC1 Analog Mute */
+	ad1843_LDA1G  = {  9,  8,  6 },	/* Left DAC1 Analog/Digital Gain */
+	ad1843_LDA1GM = {  9, 15,  1 },	/* Left DAC1 Analog Mute */
+	ad1843_RDA1AM = { 11,  7,  1 },	/* Right DAC1 Digital Mute */
+	ad1843_LDA1AM = { 11, 15,  1 },	/* Left DAC1 Digital Mute */
+	ad1843_ADLC   = { 15,  0,  2 },	/* ADC Left Sample Rate Source */
+	ad1843_ADRC   = { 15,  2,  2 },	/* ADC Right Sample Rate Source */
+	ad1843_DA1C   = { 15,  8,  2 },	/* DAC1 Sample Rate Source */
+	ad1843_C1C    = { 17,  0, 16 },	/* Clock 1 Sample Rate Select */
+	ad1843_C2C    = { 20,  0, 16 },	/* Clock 1 Sample Rate Select */
+	ad1843_DAADL  = { 25,  4,  2 },	/* Digital ADC Left Source Select */
+	ad1843_DAADR  = { 25,  6,  2 },	/* Digital ADC Right Source Select */
+	ad1843_DRSFLT = { 25, 15,  1 },	/* Digital Reampler Filter Mode */
+	ad1843_ADLF   = { 26,  0,  2 }, /* ADC Left Channel Data Format */
+	ad1843_ADRF   = { 26,  2,  2 }, /* ADC Right Channel Data Format */
+	ad1843_ADTLK  = { 26,  4,  1 },	/* ADC Transmit Lock Mode Select */
+	ad1843_SCF    = { 26,  7,  1 },	/* SCLK Frequency Select */
+	ad1843_DA1F   = { 26,  8,  2 },	/* DAC1 Data Format Select */
+	ad1843_DA1SM  = { 26, 14,  1 },	/* DAC1 Stereo/Mono Mode Select */
+	ad1843_ADLEN  = { 27,  0,  1 },	/* ADC Left Channel Enable */
+	ad1843_ADREN  = { 27,  1,  1 },	/* ADC Right Channel Enable */
+	ad1843_AAMEN  = { 27,  4,  1 },	/* Analog to Analog Mix Enable */
+	ad1843_ANAEN  = { 27,  7,  1 },	/* Analog Channel Enable */
+	ad1843_DA1EN  = { 27,  8,  1 },	/* DAC1 Enable */
+	ad1843_DA2EN  = { 27,  9,  1 },	/* DAC2 Enable */
+	ad1843_C1EN   = { 28, 11,  1 },	/* Clock Generator 1 Enable */
+	ad1843_C2EN   = { 28, 12,  1 },	/* Clock Generator 2 Enable */
+	ad1843_PDNI   = { 28, 15,  1 };	/* Converter Power Down */
+
+/*
+ * The various registers of the AD1843 use three different formats for
+ * specifying gain.  The ad1843_gain structure parameterizes the
+ * formats.
+ */
+
+typedef struct ad1843_gain {
+
+	int	negative;		/* nonzero if gain is negative. */
+	const ad1843_bitfield_t *lfield;
+	const ad1843_bitfield_t *rfield;
+
+} ad1843_gain_t;
+
+static const ad1843_gain_t ad1843_gain_RECLEV
+				= { 0, &ad1843_LIG,   &ad1843_RIG };
+static const ad1843_gain_t ad1843_gain_LINE
+				= { 1, &ad1843_LX1M,  &ad1843_RX1M };
+static const ad1843_gain_t ad1843_gain_CD
+				= { 1, &ad1843_LX2M,  &ad1843_RX2M };
+static const ad1843_gain_t ad1843_gain_MIC
+				= { 1, &ad1843_LMCM,  &ad1843_RMCM };
+static const ad1843_gain_t ad1843_gain_PCM
+				= { 1, &ad1843_LDA1G, &ad1843_RDA1G };
+
+/* read the current value of an AD1843 bitfield. */
+
+static int ad1843_read_bits(lithium_t *lith, const ad1843_bitfield_t *field)
+{
+	int w = li_read_ad1843_reg(lith, field->reg);
+	int val = w >> field->lo_bit & ((1 << field->nbits) - 1);
+
+	DBGXV("ad1843_read_bits(lith=0x%p, field->{%d %d %d}) returns 0x%x\n",
+	      lith, field->reg, field->lo_bit, field->nbits, val);
+
+	return val;
+}
+
+/*
+ * write a new value to an AD1843 bitfield and return the old value.
+ */
+
+static int ad1843_write_bits(lithium_t *lith,
+			     const ad1843_bitfield_t *field,
+			     int newval)
+{
+	int w = li_read_ad1843_reg(lith, field->reg);
+	int mask = ((1 << field->nbits) - 1) << field->lo_bit;
+	int oldval = (w & mask) >> field->lo_bit;
+	int newbits = (newval << field->lo_bit) & mask;
+	w = (w & ~mask) | newbits;
+	(void) li_write_ad1843_reg(lith, field->reg, w);
+
+	DBGXV("ad1843_write_bits(lith=0x%p, field->{%d %d %d}, val=0x%x) "
+	      "returns 0x%x\n",
+	      lith, field->reg, field->lo_bit, field->nbits, newval,
+	      oldval);
+
+	return oldval;
+}
+
+/*
+ * ad1843_read_multi reads multiple bitfields from the same AD1843
+ * register.  It uses a single read cycle to do it.  (Reading the
+ * ad1843 requires 256 bit times at 12.288 MHz, or nearly 20
+ * microseconds.)
+ *
+ * Called ike this.
+ *
+ *  ad1843_read_multi(lith, nfields,
+ *		      &ad1843_FIELD1, &val1,
+ *		      &ad1843_FIELD2, &val2, ...);
+ */
+
+static void ad1843_read_multi(lithium_t *lith, int argcount, ...)
+{
+	va_list ap;
+	const ad1843_bitfield_t *fp;
+	int w = 0, mask, *value, reg = -1;
+
+	va_start(ap, argcount);
+	while (--argcount >= 0) {
+		fp = va_arg(ap, const ad1843_bitfield_t *);
+		value = va_arg(ap, int *);
+		if (reg == -1) {
+			reg = fp->reg;
+			w = li_read_ad1843_reg(lith, reg);
+		}
+		ASSERT(reg == fp->reg);
+		mask = (1 << fp->nbits) - 1;
+		*value = w >> fp->lo_bit & mask;
+	}
+	va_end(ap);
+}
+
+/*
+ * ad1843_write_multi stores multiple bitfields into the same AD1843
+ * register.  It uses one read and one write cycle to do it.
+ *
+ * Called like this.
+ *
+ *  ad1843_write_multi(lith, nfields,
+ *		       &ad1843_FIELD1, val1,
+ *		       &ad1843_FIELF2, val2, ...);
+ */
+
+static void ad1843_write_multi(lithium_t *lith, int argcount, ...)
+{
+	va_list ap;
+	int reg;
+	const ad1843_bitfield_t *fp;
+	int value;
+	int w, m, mask, bits;
+
+	mask = 0;
+	bits = 0;
+	reg = -1;
+
+	va_start(ap, argcount);
+	while (--argcount >= 0) {
+		fp = va_arg(ap, const ad1843_bitfield_t *);
+		value = va_arg(ap, int);
+		if (reg == -1)
+			reg = fp->reg;
+		ASSERT(fp->reg == reg);
+		m = ((1 << fp->nbits) - 1) << fp->lo_bit;
+		mask |= m;
+		bits |= (value << fp->lo_bit) & m;
+	}
+	va_end(ap);
+	ASSERT(!(bits & ~mask));
+	if (~mask & 0xFFFF)
+		w = li_read_ad1843_reg(lith, reg);
+	else
+		w = 0;
+	w = (w & ~mask) | bits;
+	(void) li_write_ad1843_reg(lith, reg, w);
+}
+
+/*
+ * ad1843_get_gain reads the specified register and extracts the gain value
+ * using the supplied gain type.  It returns the gain in OSS format.
+ */
+
+static int ad1843_get_gain(lithium_t *lith, const ad1843_gain_t *gp)
+{
+	int lg, rg;
+	unsigned short mask = (1 << gp->lfield->nbits) - 1;
+
+	ad1843_read_multi(lith, 2, gp->lfield, &lg, gp->rfield, &rg);
+	if (gp->negative) {
+		lg = mask - lg;
+		rg = mask - rg;
+	}
+	lg = (lg * 100 + (mask >> 1)) / mask;
+	rg = (rg * 100 + (mask >> 1)) / mask;
+	return lg << 0 | rg << 8;
+}
+
+/*
+ * Set an audio channel's gain. Converts from OSS format to AD1843's
+ * format.
+ *
+ * Returns the new gain, which may be lower than the old gain.
+ */
+
+static int ad1843_set_gain(lithium_t *lith,
+			   const ad1843_gain_t *gp,
+			   int newval)
+{
+	unsigned short mask = (1 << gp->lfield->nbits) - 1;
+
+	int lg = newval >> 0 & 0xFF;
+	int rg = newval >> 8;
+	if (lg < 0 || lg > 100 || rg < 0 || rg > 100)
+		return -EINVAL;
+	lg = (lg * mask + (mask >> 1)) / 100;
+	rg = (rg * mask + (mask >> 1)) / 100;
+	if (gp->negative) {
+		lg = mask - lg;
+		rg = mask - rg;
+	}
+	ad1843_write_multi(lith, 2, gp->lfield, lg, gp->rfield, rg);
+	return ad1843_get_gain(lith, gp);
+}
+
+/* Returns the current recording source, in OSS format. */
+
+static int ad1843_get_recsrc(lithium_t *lith)
+{
+	int ls = ad1843_read_bits(lith, &ad1843_LSS);
+
+	switch (ls) {
+	case 1:
+		return SOUND_MASK_MIC;
+	case 2:
+		return SOUND_MASK_LINE;
+	case 3:
+		return SOUND_MASK_CD;
+	case 6:
+		return SOUND_MASK_PCM;
+	default:
+		ASSERT(0);
+		return -1;
+	}
+}
+
+/*
+ * Enable/disable digital resample mode in the AD1843.
+ *
+ * The AD1843 requires that ADL, ADR, DA1 and DA2 be powered down
+ * while switching modes.  So we save DA1's state (DA2's state is not
+ * interesting), power them down, switch into/out of resample mode,
+ * power them up, and restore state.
+ *
+ * This will cause audible glitches if D/A or A/D is going on, so the
+ * driver disallows that (in mixer_write_ioctl()).
+ *
+ * The open question is, is this worth doing?  I'm leaving it in,
+ * because it's written, but...
+ */
+
+static void ad1843_set_resample_mode(lithium_t *lith, int onoff)
+{
+	/* Save DA1 mute and gain (addr 9 is DA1 analog gain/attenuation) */
+	int save_da1 = li_read_ad1843_reg(lith, 9);
+
+	/* Power down A/D and D/A. */
+	ad1843_write_multi(lith, 4,
+			   &ad1843_DA1EN, 0,
+			   &ad1843_DA2EN, 0,
+			   &ad1843_ADLEN, 0,
+			   &ad1843_ADREN, 0);
+
+	/* Switch mode */
+	ASSERT(onoff == 0 || onoff == 1);
+	ad1843_write_bits(lith, &ad1843_DRSFLT, onoff);
+
+ 	/* Power up A/D and D/A. */
+	ad1843_write_multi(lith, 3,
+			   &ad1843_DA1EN, 1,
+			   &ad1843_ADLEN, 1,
+			   &ad1843_ADREN, 1);
+
+	/* Restore DA1 mute and gain. */
+	li_write_ad1843_reg(lith, 9, save_da1);
+}
+
+/*
+ * Set recording source.  Arg newsrc specifies an OSS channel mask.
+ *
+ * The complication is that when we switch into/out of loopback mode
+ * (i.e., src = SOUND_MASK_PCM), we change the AD1843 into/out of
+ * digital resampling mode.
+ *
+ * Returns newsrc on success, -errno on failure.
+ */
+
+static int ad1843_set_recsrc(lithium_t *lith, int newsrc)
+{
+	int bits;
+	int oldbits;
+
+	switch (newsrc) {
+	case SOUND_MASK_PCM:
+		bits = 6;
+		break;
+
+	case SOUND_MASK_MIC:
+		bits = 1;
+		break;
+
+	case SOUND_MASK_LINE:
+		bits = 2;
+		break;
+
+	case SOUND_MASK_CD:
+		bits = 3;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+	oldbits = ad1843_read_bits(lith, &ad1843_LSS);
+	if (newsrc == SOUND_MASK_PCM && oldbits != 6) {
+		DBGP("enabling digital resample mode\n");
+		ad1843_set_resample_mode(lith, 1);
+		ad1843_write_multi(lith, 2,
+				   &ad1843_DAADL, 2,
+				   &ad1843_DAADR, 2);
+	} else if (newsrc != SOUND_MASK_PCM && oldbits == 6) {
+		DBGP("disabling digital resample mode\n");
+		ad1843_set_resample_mode(lith, 0);
+		ad1843_write_multi(lith, 2,
+				   &ad1843_DAADL, 0,
+				   &ad1843_DAADR, 0);
+	}
+	ad1843_write_multi(lith, 2, &ad1843_LSS, bits, &ad1843_RSS, bits);
+	return newsrc;
+}
+
+/*
+ * Return current output sources, in OSS format.
+ */
+
+static int ad1843_get_outsrc(lithium_t *lith)
+{
+	int pcm, line, mic, cd;
+
+	pcm  = ad1843_read_bits(lith, &ad1843_LDA1GM) ? 0 : SOUND_MASK_PCM;
+	line = ad1843_read_bits(lith, &ad1843_LX1MM)  ? 0 : SOUND_MASK_LINE;
+	cd   = ad1843_read_bits(lith, &ad1843_LX2MM)  ? 0 : SOUND_MASK_CD;
+	mic  = ad1843_read_bits(lith, &ad1843_LMCMM)  ? 0 : SOUND_MASK_MIC;
+
+	return pcm | line | cd | mic;
+}
+
+/*
+ * Set output sources.  Arg is a mask of active sources in OSS format.
+ *
+ * Returns source mask on success, -errno on failure.
+ */
+
+static int ad1843_set_outsrc(lithium_t *lith, int mask)
+{
+	int pcm, line, mic, cd;
+
+	if (mask & ~(SOUND_MASK_PCM | SOUND_MASK_LINE |
+		     SOUND_MASK_CD | SOUND_MASK_MIC))
+		return -EINVAL;
+	pcm  = (mask & SOUND_MASK_PCM)  ? 0 : 1;
+	line = (mask & SOUND_MASK_LINE) ? 0 : 1;
+	mic  = (mask & SOUND_MASK_MIC)  ? 0 : 1;
+	cd   = (mask & SOUND_MASK_CD)   ? 0 : 1;
+
+	ad1843_write_multi(lith, 2, &ad1843_LDA1GM, pcm, &ad1843_RDA1GM, pcm);
+	ad1843_write_multi(lith, 2, &ad1843_LX1MM, line, &ad1843_RX1MM, line);
+	ad1843_write_multi(lith, 2, &ad1843_LX2MM, cd,   &ad1843_RX2MM, cd);
+	ad1843_write_multi(lith, 2, &ad1843_LMCMM, mic,  &ad1843_RMCMM, mic);
+
+	return mask;
+}
+
+/* Setup ad1843 for D/A conversion. */
+
+static void ad1843_setup_dac(lithium_t *lith,
+			     int framerate,
+			     int fmt,
+			     int channels)
+{
+	int ad_fmt = 0, ad_mode = 0;
+
+	DBGEV("(lith=0x%p, framerate=%d, fmt=%d, channels=%d)\n",
+	      lith, framerate, fmt, channels);
+
+	switch (fmt) {
+	case AFMT_S8:		ad_fmt = 1; break;
+	case AFMT_U8:		ad_fmt = 1; break;
+	case AFMT_S16_LE:	ad_fmt = 1; break;
+	case AFMT_MU_LAW:	ad_fmt = 2; break;
+	case AFMT_A_LAW:	ad_fmt = 3; break;
+	default:		ASSERT(0);
+	}
+
+	switch (channels) {
+	case 2:			ad_mode = 0; break;
+	case 1:			ad_mode = 1; break;
+	default:		ASSERT(0);
+	}
+		
+	DBGPV("ad_mode = %d, ad_fmt = %d\n", ad_mode, ad_fmt);
+	ASSERT(framerate >= 4000 && framerate <= 49000);
+	ad1843_write_bits(lith, &ad1843_C1C, framerate);
+	ad1843_write_multi(lith, 2,
+			   &ad1843_DA1SM, ad_mode, &ad1843_DA1F, ad_fmt);
+}
+
+static void ad1843_shutdown_dac(lithium_t *lith)
+{
+	ad1843_write_bits(lith, &ad1843_DA1F, 1);
+}
+
+static void ad1843_setup_adc(lithium_t *lith, int framerate, int fmt, int channels)
+{
+	int da_fmt = 0;
+
+	DBGEV("(lith=0x%p, framerate=%d, fmt=%d, channels=%d)\n",
+	      lith, framerate, fmt, channels);
+
+	switch (fmt) {
+	case AFMT_S8:		da_fmt = 1; break;
+	case AFMT_U8:		da_fmt = 1; break;
+	case AFMT_S16_LE:	da_fmt = 1; break;
+	case AFMT_MU_LAW:	da_fmt = 2; break;
+	case AFMT_A_LAW:	da_fmt = 3; break;
+	default:		ASSERT(0);
+	}
+
+	DBGPV("da_fmt = %d\n", da_fmt);
+	ASSERT(framerate >= 4000 && framerate <= 49000);
+	ad1843_write_bits(lith, &ad1843_C2C, framerate);
+	ad1843_write_multi(lith, 2,
+			   &ad1843_ADLF, da_fmt, &ad1843_ADRF, da_fmt);
+}
+
+static void ad1843_shutdown_adc(lithium_t *lith)
+{
+	/* nothing to do */
+}
+
+/*
+ * Fully initialize the ad1843.  As described in the AD1843 data
+ * sheet, section "START-UP SEQUENCE".  The numbered comments are
+ * subsection headings from the data sheet.  See the data sheet, pages
+ * 52-54, for more info.
+ *
+ * return 0 on success, -errno on failure.  */
+
+static int __init ad1843_init(lithium_t *lith)
+{
+	unsigned long later;
+	int err;
+
+	err = li_init(lith);
+	if (err)
+		return err;
+
+	if (ad1843_read_bits(lith, &ad1843_INIT) != 0) {
+		printk(KERN_ERR "vwsnd sound: AD1843 won't initialize\n");
+		return -EIO;
+	}
+
+	ad1843_write_bits(lith, &ad1843_SCF, 1);
+
+	/* 4. Put the conversion resources into standby. */
+
+	ad1843_write_bits(lith, &ad1843_PDNI, 0);
+	later = jiffies + HZ / 2;	/* roughly half a second */
+	DBGDO(shut_up++);
+	while (ad1843_read_bits(lith, &ad1843_PDNO)) {
+		if (time_after(jiffies, later)) {
+			printk(KERN_ERR
+			       "vwsnd audio: AD1843 won't power up\n");
+			return -EIO;
+		}
+		schedule();
+	}
+	DBGDO(shut_up--);
+
+	/* 5. Power up the clock generators and enable clock output pins. */
+
+	ad1843_write_multi(lith, 2, &ad1843_C1EN, 1, &ad1843_C2EN, 1);
+
+	/* 6. Configure conversion resources while they are in standby. */
+
+ 	/* DAC1 uses clock 1 as source, ADC uses clock 2.  Always. */
+
+	ad1843_write_multi(lith, 3,
+			   &ad1843_DA1C, 1,
+			   &ad1843_ADLC, 2,
+			   &ad1843_ADRC, 2);
+
+	/* 7. Enable conversion resources. */
+
+	ad1843_write_bits(lith, &ad1843_ADTLK, 1);
+	ad1843_write_multi(lith, 5,
+			   &ad1843_ANAEN, 1,
+			   &ad1843_AAMEN, 1,
+			   &ad1843_DA1EN, 1,
+			   &ad1843_ADLEN, 1,
+			   &ad1843_ADREN, 1);
+
+	/* 8. Configure conversion resources while they are enabled. */
+
+	ad1843_write_bits(lith, &ad1843_DA1C, 1);
+
+	/* Unmute all channels. */
+
+	ad1843_set_outsrc(lith,
+			  (SOUND_MASK_PCM | SOUND_MASK_LINE |
+			   SOUND_MASK_MIC | SOUND_MASK_CD));
+	ad1843_write_multi(lith, 2, &ad1843_LDA1AM, 0, &ad1843_RDA1AM, 0);
+
+	/* Set default recording source to Line In and set
+	 * mic gain to +20 dB.
+	 */
+
+	ad1843_set_recsrc(lith, SOUND_MASK_LINE);
+	ad1843_write_multi(lith, 2, &ad1843_LMGE, 1, &ad1843_RMGE, 1);
+
+	/* Set Speaker Out level to +/- 4V and unmute it. */
+
+	ad1843_write_multi(lith, 2, &ad1843_HPOS, 1, &ad1843_HPOM, 0);
+
+	return 0;
+}
+
+/*****************************************************************************/
+/* PCM I/O */
+
+#define READ_INTR_MASK  (LI_INTR_COMM1_TRIG | LI_INTR_COMM1_OVERFLOW)
+#define WRITE_INTR_MASK (LI_INTR_COMM2_TRIG | LI_INTR_COMM2_UNDERFLOW)
+
+typedef enum vwsnd_port_swstate {	/* software state */
+	SW_OFF,
+	SW_INITIAL,
+	SW_RUN,
+	SW_DRAIN,
+} vwsnd_port_swstate_t;
+
+typedef enum vwsnd_port_hwstate {	/* hardware state */
+	HW_STOPPED,
+	HW_RUNNING,
+} vwsnd_port_hwstate_t;
+
+/*
+ * These flags are read by ISR, but only written at baseline.
+ */
+
+typedef enum vwsnd_port_flags {
+	DISABLED = 1 << 0,
+	ERFLOWN  = 1 << 1,		/* overflown or underflown */
+	HW_BUSY  = 1 << 2,
+} vwsnd_port_flags_t;
+
+/*
+ * vwsnd_port is the per-port data structure.  Each device has two
+ * ports, one for input and one for output.
+ *
+ * Locking:
+ *
+ *	port->lock protects: hwstate, flags, swb_[iu]_avail.
+ *
+ *	devc->io_sema protects: swstate, sw_*, swb_[iu]_idx.
+ *
+ *	everything else is only written by open/release or
+ *	pcm_{setup,shutdown}(), which are serialized by a
+ *	combination of devc->open_sema and devc->io_sema.
+ */
+
+typedef struct vwsnd_port {
+
+	spinlock_t	lock;
+	wait_queue_head_t queue;
+	vwsnd_port_swstate_t swstate;
+	vwsnd_port_hwstate_t hwstate;
+	vwsnd_port_flags_t flags;
+
+	int		sw_channels;
+	int		sw_samplefmt;
+	int		sw_framerate;
+	int		sample_size;
+	int		frame_size;
+	unsigned int	zero_word;	/* zero for the sample format */
+
+	int		sw_fragshift;
+	int		sw_fragcount;
+	int		sw_subdivshift;
+
+	unsigned int	hw_fragshift;
+	unsigned int	hw_fragsize;
+	unsigned int	hw_fragcount;
+
+	int		hwbuf_size;
+	unsigned long	hwbuf_paddr;
+	unsigned long	hwbuf_vaddr;
+	void *		hwbuf;		/* hwbuf == hwbuf_vaddr */
+	int		hwbuf_max;	/* max bytes to preload */
+
+	void *		swbuf;
+	unsigned int	swbuf_size;	/* size in bytes */
+	unsigned int	swb_u_idx;	/* index of next user byte */
+	unsigned int	swb_i_idx;	/* index of next intr byte */
+	unsigned int	swb_u_avail;	/* # bytes avail to user */
+	unsigned int	swb_i_avail;	/* # bytes avail to intr */
+
+	dma_chan_t	chan;
+
+	/* Accounting */
+
+	int		byte_count;
+	int		frag_count;
+	int		MSC_offset;
+
+} vwsnd_port_t;
+
+/* vwsnd_dev is the per-device data structure. */
+
+typedef struct vwsnd_dev {
+	struct vwsnd_dev *next_dev;
+	int		audio_minor;	/* minor number of audio device */
+	int		mixer_minor;	/* minor number of mixer device */
+
+	struct semaphore open_sema;
+	struct semaphore io_sema;
+	struct semaphore mix_sema;
+	mode_t		open_mode;
+	wait_queue_head_t open_wait;
+
+	lithium_t	lith;
+
+	vwsnd_port_t	rport;
+	vwsnd_port_t	wport;
+} vwsnd_dev_t;
+
+static vwsnd_dev_t *vwsnd_dev_list;	/* linked list of all devices */
+
+static atomic_t vwsnd_use_count = ATOMIC_INIT(0);
+
+# define INC_USE_COUNT (atomic_inc(&vwsnd_use_count))
+# define DEC_USE_COUNT (atomic_dec(&vwsnd_use_count))
+# define IN_USE        (atomic_read(&vwsnd_use_count) != 0)
+
+/*
+ * Lithium can only DMA multiples of 32 bytes.  Its DMA buffer may
+ * be up to 8 Kb.  This driver always uses 8 Kb.
+ *
+ * Memory bug workaround -- I'm not sure what's going on here, but
+ * somehow pcm_copy_out() was triggering segv's going on to the next
+ * page of the hw buffer.  So, I make the hw buffer one size bigger
+ * than we actually use.  That way, the following page is allocated
+ * and mapped, and no error.  I suspect that something is broken
+ * in Cobalt, but haven't really investigated.  HBO is the actual
+ * size of the buffer, and HWBUF_ORDER is what we allocate.
+ */
+
+#define HWBUF_SHIFT 13
+#define HWBUF_SIZE (1 << HWBUF_SHIFT)
+# define HBO         (HWBUF_SHIFT > PAGE_SHIFT ? HWBUF_SHIFT - PAGE_SHIFT : 0)
+# define HWBUF_ORDER (HBO + 1)		/* next size bigger */
+#define MIN_SPEED 4000
+#define MAX_SPEED 49000
+
+#define MIN_FRAGSHIFT			(DMACHUNK_SHIFT + 1)
+#define MAX_FRAGSHIFT			(PAGE_SHIFT)
+#define MIN_FRAGSIZE			(1 << MIN_FRAGSHIFT)
+#define MAX_FRAGSIZE			(1 << MAX_FRAGSHIFT)
+#define MIN_FRAGCOUNT(fragsize)		3
+#define MAX_FRAGCOUNT(fragsize)		(32 * PAGE_SIZE / (fragsize))
+#define DEFAULT_FRAGSHIFT		12
+#define DEFAULT_FRAGCOUNT		16
+#define DEFAULT_SUBDIVSHIFT		0
+
+/*
+ * The software buffer (swbuf) is a ring buffer shared between user
+ * level and interrupt level.  Each level owns some of the bytes in
+ * the buffer, and may give bytes away by calling swb_inc_{u,i}().
+ * User level calls _u for user, and interrupt level calls _i for
+ * interrupt.
+ *
+ * port->swb_{u,i}_avail is the number of bytes available to that level.
+ *
+ * port->swb_{u,i}_idx is the index of the first available byte in the
+ * buffer.
+ *
+ * Each level calls swb_inc_{u,i}() to atomically increment its index,
+ * recalculate the number of bytes available for both sides, and
+ * return the number of bytes available.  Since each side can only
+ * give away bytes, the other side can only increase the number of
+ * bytes available to this side.  Each side updates its own index
+ * variable, swb_{u,i}_idx, so no lock is needed to read it.
+ *
+ * To query the number of bytes available, call swb_inc_{u,i} with an
+ * increment of zero.
+ */
+
+static __inline__ unsigned int __swb_inc_u(vwsnd_port_t *port, int inc)
+{
+	if (inc) {
+		port->swb_u_idx += inc;
+		port->swb_u_idx %= port->swbuf_size;
+		port->swb_u_avail -= inc;
+		port->swb_i_avail += inc;
+	}
+	return port->swb_u_avail;
+}
+
+static __inline__ unsigned int swb_inc_u(vwsnd_port_t *port, int inc)
+{
+	unsigned long flags;
+	unsigned int ret;
+
+	spin_lock_irqsave(&port->lock, flags);
+	{
+		ret = __swb_inc_u(port, inc);
+	}
+	spin_unlock_irqrestore(&port->lock, flags);
+	return ret;
+}
+
+static __inline__ unsigned int __swb_inc_i(vwsnd_port_t *port, int inc)
+{
+	if (inc) {
+		port->swb_i_idx += inc;
+		port->swb_i_idx %= port->swbuf_size;
+		port->swb_i_avail -= inc;
+		port->swb_u_avail += inc;
+	}
+	return port->swb_i_avail;
+}
+
+static __inline__ unsigned int swb_inc_i(vwsnd_port_t *port, int inc)
+{
+	unsigned long flags;
+	unsigned int ret;
+
+	spin_lock_irqsave(&port->lock, flags);
+	{
+		ret = __swb_inc_i(port, inc);
+	}
+	spin_unlock_irqrestore(&port->lock, flags);
+	return ret;
+}
+
+/*
+ * pcm_setup - this routine initializes all port state after
+ * mode-setting ioctls have been done, but before the first I/O is
+ * done.
+ *
+ * Locking: called with devc->io_sema held.
+ *
+ * Returns 0 on success, -errno on failure.
+ */
+
+static int pcm_setup(vwsnd_dev_t *devc,
+		     vwsnd_port_t *rport,
+		     vwsnd_port_t *wport)
+{
+	vwsnd_port_t *aport = rport ? rport : wport;
+	int sample_size;
+	unsigned int zero_word;
+
+	DBGEV("(devc=0x%p, rport=0x%p, wport=0x%p)\n", devc, rport, wport);
+
+	ASSERT(aport != NULL);
+	if (aport->swbuf != NULL)
+		return 0;
+	switch (aport->sw_samplefmt) {
+	case AFMT_MU_LAW:
+		sample_size = 1;
+		zero_word = 0xFFFFFFFF ^ 0x80808080;
+		break;
+
+	case AFMT_A_LAW:
+		sample_size = 1;
+		zero_word = 0xD5D5D5D5 ^ 0x80808080;
+		break;
+
+	case AFMT_U8:
+		sample_size = 1;
+		zero_word = 0x80808080;
+		break;
+
+	case AFMT_S8:
+		sample_size = 1;
+		zero_word = 0x00000000;
+		break;
+
+	case AFMT_S16_LE:
+		sample_size = 2;
+		zero_word = 0x00000000;
+		break;
+
+	default:
+		sample_size = 0;	/* prevent compiler warning */
+		zero_word = 0;
+		ASSERT(0);
+	}
+	aport->sample_size  = sample_size;
+	aport->zero_word    = zero_word;
+	aport->frame_size   = aport->sw_channels * aport->sample_size;
+	aport->hw_fragshift = aport->sw_fragshift - aport->sw_subdivshift;
+	aport->hw_fragsize  = 1 << aport->hw_fragshift;
+	aport->hw_fragcount = aport->sw_fragcount << aport->sw_subdivshift;
+	ASSERT(aport->hw_fragsize >= MIN_FRAGSIZE);
+	ASSERT(aport->hw_fragsize <= MAX_FRAGSIZE);
+	ASSERT(aport->hw_fragcount >= MIN_FRAGCOUNT(aport->hw_fragsize));
+	ASSERT(aport->hw_fragcount <= MAX_FRAGCOUNT(aport->hw_fragsize));
+	if (rport) {
+		int hwfrags, swfrags;
+		rport->hwbuf_max = aport->hwbuf_size - DMACHUNK_SIZE;
+		hwfrags = rport->hwbuf_max >> aport->hw_fragshift;
+		swfrags = aport->hw_fragcount - hwfrags;
+		if (swfrags < 2)
+			swfrags = 2;
+		rport->swbuf_size = swfrags * aport->hw_fragsize;
+		DBGPV("hwfrags = %d, swfrags = %d\n", hwfrags, swfrags);
+		DBGPV("read hwbuf_max = %d, swbuf_size = %d\n",
+		     rport->hwbuf_max, rport->swbuf_size);
+	}
+	if (wport) {
+		int hwfrags, swfrags;
+		int total_bytes = aport->hw_fragcount * aport->hw_fragsize;
+		wport->hwbuf_max = aport->hwbuf_size - DMACHUNK_SIZE;
+		if (wport->hwbuf_max > total_bytes)
+			wport->hwbuf_max = total_bytes;
+		hwfrags = wport->hwbuf_max >> aport->hw_fragshift;
+		DBGPV("hwfrags = %d\n", hwfrags);
+		swfrags = aport->hw_fragcount - hwfrags;
+		if (swfrags < 2)
+			swfrags = 2;
+		wport->swbuf_size = swfrags * aport->hw_fragsize;
+		DBGPV("hwfrags = %d, swfrags = %d\n", hwfrags, swfrags);
+		DBGPV("write hwbuf_max = %d, swbuf_size = %d\n",
+		     wport->hwbuf_max, wport->swbuf_size);
+	}
+
+	aport->swb_u_idx    = 0;
+	aport->swb_i_idx    = 0;
+	aport->byte_count   = 0;
+
+	/*
+	 * Is this a Cobalt bug?  We need to make this buffer extend
+	 * one page further than we actually use -- somehow memcpy
+	 * causes an exceptoin otherwise.  I suspect there's a bug in
+	 * Cobalt (or somewhere) where it's generating a fault on a
+	 * speculative load or something.  Obviously, I haven't taken
+	 * the time to track it down.
+	 */
+
+	aport->swbuf        = vmalloc(aport->swbuf_size + PAGE_SIZE);
+	if (!aport->swbuf)
+		return -ENOMEM;
+	if (rport && wport) {
+		ASSERT(aport == rport);
+		ASSERT(wport->swbuf == NULL);
+		/* One extra page - see comment above. */
+		wport->swbuf = vmalloc(aport->swbuf_size + PAGE_SIZE);
+		if (!wport->swbuf) {
+			vfree(aport->swbuf);
+			aport->swbuf = NULL;
+			return -ENOMEM;
+		}
+		wport->sample_size  = rport->sample_size;
+		wport->zero_word    = rport->zero_word;
+		wport->frame_size   = rport->frame_size;
+		wport->hw_fragshift = rport->hw_fragshift;
+		wport->hw_fragsize  = rport->hw_fragsize;
+		wport->hw_fragcount = rport->hw_fragcount;
+		wport->swbuf_size   = rport->swbuf_size;
+		wport->hwbuf_max    = rport->hwbuf_max;
+		wport->swb_u_idx    = rport->swb_u_idx;
+		wport->swb_i_idx    = rport->swb_i_idx;
+		wport->byte_count   = rport->byte_count;
+	}
+	if (rport) {
+		rport->swb_u_avail = 0;
+		rport->swb_i_avail = rport->swbuf_size;
+		rport->swstate = SW_RUN;
+		li_setup_dma(&rport->chan,
+			     &li_comm1,
+			     &devc->lith,
+			     rport->hwbuf_paddr,
+			     HWBUF_SHIFT,
+			     rport->hw_fragshift,
+			     rport->sw_channels,
+			     rport->sample_size);
+		ad1843_setup_adc(&devc->lith,
+				 rport->sw_framerate,
+				 rport->sw_samplefmt,
+				 rport->sw_channels);
+		li_enable_interrupts(&devc->lith, READ_INTR_MASK);
+		if (!(rport->flags & DISABLED)) {
+			ustmsc_t ustmsc;
+			rport->hwstate = HW_RUNNING;
+			li_activate_dma(&rport->chan);
+			li_read_USTMSC(&rport->chan, &ustmsc);
+			rport->MSC_offset = ustmsc.msc;
+		}
+	}
+	if (wport) {
+		if (wport->hwbuf_max > wport->swbuf_size)
+			wport->hwbuf_max = wport->swbuf_size;
+		wport->flags &= ~ERFLOWN;
+		wport->swb_u_avail = wport->swbuf_size;
+		wport->swb_i_avail = 0;
+		wport->swstate = SW_RUN;
+		li_setup_dma(&wport->chan,
+			     &li_comm2,
+			     &devc->lith,
+			     wport->hwbuf_paddr,
+			     HWBUF_SHIFT,
+			     wport->hw_fragshift,
+			     wport->sw_channels,
+			     wport->sample_size);
+		ad1843_setup_dac(&devc->lith,
+				 wport->sw_framerate,
+				 wport->sw_samplefmt,
+				 wport->sw_channels);
+		li_enable_interrupts(&devc->lith, WRITE_INTR_MASK);
+	}
+	DBGRV();
+	return 0;
+}
+
+/*
+ * pcm_shutdown_port - shut down one port (direction) for PCM I/O.
+ * Only called from pcm_shutdown.
+ */
+
+static void pcm_shutdown_port(vwsnd_dev_t *devc,
+			      vwsnd_port_t *aport,
+			      unsigned int mask)
+{
+	unsigned long flags;
+	vwsnd_port_hwstate_t hwstate;
+	DECLARE_WAITQUEUE(wait, current);
+
+	aport->swstate = SW_INITIAL;
+	add_wait_queue(&aport->queue, &wait);
+	while (1) {
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		spin_lock_irqsave(&aport->lock, flags);
+		{
+			hwstate = aport->hwstate;
+		}		
+		spin_unlock_irqrestore(&aport->lock, flags);
+		if (hwstate == HW_STOPPED)
+			break;
+		schedule();
+	}
+	current->state = TASK_RUNNING;
+	remove_wait_queue(&aport->queue, &wait);
+	li_disable_interrupts(&devc->lith, mask);
+	if (aport == &devc->rport)
+		ad1843_shutdown_adc(&devc->lith);
+	else /* aport == &devc->wport) */
+		ad1843_shutdown_dac(&devc->lith);
+	li_shutdown_dma(&aport->chan);
+	vfree(aport->swbuf);
+	aport->swbuf = NULL;
+	aport->byte_count = 0;
+}
+
+/*
+ * pcm_shutdown undoes what pcm_setup did.
+ * Also sets the ports' swstate to newstate.
+ */
+
+static void pcm_shutdown(vwsnd_dev_t *devc,
+			 vwsnd_port_t *rport,
+			 vwsnd_port_t *wport)
+{
+	DBGEV("(devc=0x%p, rport=0x%p, wport=0x%p)\n", devc, rport, wport);
+
+	if (rport && rport->swbuf) {
+		DBGPV("shutting down rport\n");
+		pcm_shutdown_port(devc, rport, READ_INTR_MASK);
+	}
+	if (wport && wport->swbuf) {
+		DBGPV("shutting down wport\n");
+		pcm_shutdown_port(devc, wport, WRITE_INTR_MASK);
+	}
+	DBGRV();
+}
+
+static void pcm_copy_in(vwsnd_port_t *rport, int swidx, int hwidx, int nb)
+{
+	char *src = rport->hwbuf + hwidx;
+	char *dst = rport->swbuf + swidx;
+	int fmt = rport->sw_samplefmt;
+
+	DBGPV("swidx = %d, hwidx = %d\n", swidx, hwidx);
+	ASSERT(rport->hwbuf != NULL);
+	ASSERT(rport->swbuf != NULL);
+	ASSERT(nb > 0 && (nb % 32) == 0);
+	ASSERT(swidx % 32 == 0 && hwidx % 32 == 0);
+	ASSERT(swidx >= 0 && swidx + nb <= rport->swbuf_size);
+	ASSERT(hwidx >= 0 && hwidx + nb <= rport->hwbuf_size);
+
+	if (fmt == AFMT_MU_LAW || fmt == AFMT_A_LAW || fmt == AFMT_S8) {
+
+		/* See Sample Format Notes above. */
+
+		char *end = src + nb;
+		while (src < end)
+			*dst++ = *src++ ^ 0x80;
+	} else
+		memcpy(dst, src, nb);
+}
+
+static void pcm_copy_out(vwsnd_port_t *wport, int swidx, int hwidx, int nb)
+{
+	char *src = wport->swbuf + swidx;
+	char *dst = wport->hwbuf + hwidx;
+	int fmt = wport->sw_samplefmt;
+
+	ASSERT(nb > 0 && (nb % 32) == 0);
+	ASSERT(wport->hwbuf != NULL);
+	ASSERT(wport->swbuf != NULL);
+	ASSERT(swidx % 32 == 0 && hwidx % 32 == 0);
+	ASSERT(swidx >= 0 && swidx + nb <= wport->swbuf_size);
+	ASSERT(hwidx >= 0 && hwidx + nb <= wport->hwbuf_size);
+	if (fmt == AFMT_MU_LAW || fmt == AFMT_A_LAW || fmt == AFMT_S8) {
+
+		/* See Sample Format Notes above. */
+
+		char *end = src + nb;
+		while (src < end)
+			*dst++ = *src++ ^ 0x80;
+	} else
+		memcpy(dst, src, nb);
+}
+
+/*
+ * pcm_output() is called both from baselevel and from interrupt level.
+ * This is where audio frames are copied into the hardware-accessible
+ * ring buffer.
+ *
+ * Locking note: The part of this routine that figures out what to do
+ * holds wport->lock.  The longer part releases wport->lock, but sets
+ * wport->flags & HW_BUSY.  Afterward, it reacquires wport->lock, and
+ * checks for more work to do.
+ *
+ * If another thread calls pcm_output() while HW_BUSY is set, it
+ * returns immediately, knowing that the thread that set HW_BUSY will
+ * look for more work to do before returning.
+ *
+ * This has the advantage that port->lock is held for several short
+ * periods instead of one long period.  Also, when pcm_output is
+ * called from base level, it reenables interrupts.
+ */
+
+static void pcm_output(vwsnd_dev_t *devc, int erflown, int nb)
+{
+	vwsnd_port_t *wport = &devc->wport;
+	const int hwmax  = wport->hwbuf_max;
+	const int hwsize = wport->hwbuf_size;
+	const int swsize = wport->swbuf_size;
+	const int fragsize = wport->hw_fragsize;
+	unsigned long iflags;
+
+	DBGEV("(devc=0x%p, erflown=%d, nb=%d)\n", devc, erflown, nb);
+	spin_lock_irqsave(&wport->lock, iflags);
+	if (erflown)
+		wport->flags |= ERFLOWN;
+	(void) __swb_inc_u(wport, nb);
+	if (wport->flags & HW_BUSY) {
+		spin_unlock_irqrestore(&wport->lock, iflags);
+		DBGPV("returning: HW BUSY\n");
+		return;
+	}
+	if (wport->flags & DISABLED) {
+		spin_unlock_irqrestore(&wport->lock, iflags);
+		DBGPV("returning: DISABLED\n");
+		return;
+	}
+	wport->flags |= HW_BUSY;
+	while (1) {
+		int swptr, hwptr, hw_avail, sw_avail, swidx;
+		vwsnd_port_hwstate_t hwstate = wport->hwstate;
+		vwsnd_port_swstate_t swstate = wport->swstate;
+		int hw_unavail;
+		ustmsc_t ustmsc;
+
+		hwptr = li_read_hwptr(&wport->chan);
+		swptr = li_read_swptr(&wport->chan);
+		hw_unavail = (swptr - hwptr + hwsize) % hwsize;
+		hw_avail = (hwmax - hw_unavail) & -fragsize;
+		sw_avail = wport->swb_i_avail & -fragsize;
+		if (sw_avail && swstate == SW_RUN) {
+			if (wport->flags & ERFLOWN) {
+				wport->flags &= ~ERFLOWN;
+			}
+		} else if (swstate == SW_INITIAL ||
+			 swstate == SW_OFF ||
+			 (swstate == SW_DRAIN &&
+			  !sw_avail &&
+			  (wport->flags & ERFLOWN))) {
+			DBGP("stopping.  hwstate = %d\n", hwstate);
+			if (hwstate != HW_STOPPED) {
+				li_deactivate_dma(&wport->chan);
+				wport->hwstate = HW_STOPPED;
+			}
+			wake_up(&wport->queue);
+			break;
+		}
+		if (!sw_avail || !hw_avail)
+			break;
+		spin_unlock_irqrestore(&wport->lock, iflags);
+
+		/*
+		 * We gave up the port lock, but we have the HW_BUSY flag.
+		 * Proceed without accessing any nonlocal state.
+		 * Do not exit the loop -- must check for more work.
+		 */
+
+		swidx = wport->swb_i_idx;
+		nb = hw_avail;
+		if (nb > sw_avail)
+			nb = sw_avail;
+		if (nb > hwsize - swptr)
+			nb = hwsize - swptr; /* don't overflow hwbuf */
+		if (nb > swsize - swidx)
+			nb = swsize - swidx; /* don't overflow swbuf */
+		ASSERT(nb > 0);
+		if (nb % fragsize) {
+			DBGP("nb = %d, fragsize = %d\n", nb, fragsize);
+			DBGP("hw_avail = %d\n", hw_avail);
+			DBGP("sw_avail = %d\n", sw_avail);
+			DBGP("hwsize = %d, swptr = %d\n", hwsize, swptr);
+			DBGP("swsize = %d, swidx = %d\n", swsize, swidx);
+		}
+		ASSERT(!(nb % fragsize));
+		DBGPV("copying swb[%d..%d] to hwb[%d..%d]\n",
+		      swidx, swidx + nb, swptr, swptr + nb);
+		pcm_copy_out(wport, swidx, swptr, nb);
+		li_write_swptr(&wport->chan, (swptr + nb) % hwsize);
+		spin_lock_irqsave(&wport->lock, iflags);
+		if (hwstate == HW_STOPPED) {
+			DBGPV("starting\n");
+			li_activate_dma(&wport->chan);
+			wport->hwstate = HW_RUNNING;
+			li_read_USTMSC(&wport->chan, &ustmsc);
+			ASSERT(wport->byte_count % wport->frame_size == 0);
+			wport->MSC_offset = ustmsc.msc - wport->byte_count / wport->frame_size;
+		}
+		__swb_inc_i(wport, nb);
+		wport->byte_count += nb;
+		wport->frag_count += nb / fragsize;
+		ASSERT(nb % fragsize == 0);
+		wake_up(&wport->queue);
+	}
+	wport->flags &= ~HW_BUSY;
+	spin_unlock_irqrestore(&wport->lock, iflags);
+	DBGRV();
+}
+
+/*
+ * pcm_input() is called both from baselevel and from interrupt level.
+ * This is where audio frames are copied out of the hardware-accessible
+ * ring buffer.
+ *
+ * Locking note: The part of this routine that figures out what to do
+ * holds rport->lock.  The longer part releases rport->lock, but sets
+ * rport->flags & HW_BUSY.  Afterward, it reacquires rport->lock, and
+ * checks for more work to do.
+ *
+ * If another thread calls pcm_input() while HW_BUSY is set, it
+ * returns immediately, knowing that the thread that set HW_BUSY will
+ * look for more work to do before returning.
+ *
+ * This has the advantage that port->lock is held for several short
+ * periods instead of one long period.  Also, when pcm_input is
+ * called from base level, it reenables interrupts.
+ */
+
+static void pcm_input(vwsnd_dev_t *devc, int erflown, int nb)
+{
+	vwsnd_port_t *rport = &devc->rport;
+	const int hwmax  = rport->hwbuf_max;
+	const int hwsize = rport->hwbuf_size;
+	const int swsize = rport->swbuf_size;
+	const int fragsize = rport->hw_fragsize;
+	unsigned long iflags;
+
+	DBGEV("(devc=0x%p, erflown=%d, nb=%d)\n", devc, erflown, nb);
+
+	spin_lock_irqsave(&rport->lock, iflags);
+	if (erflown)
+		rport->flags |= ERFLOWN;
+	(void) __swb_inc_u(rport, nb);
+	if (rport->flags & HW_BUSY || !rport->swbuf) {
+		spin_unlock_irqrestore(&rport->lock, iflags);
+		DBGPV("returning: HW BUSY or !swbuf\n");
+		return;
+	}
+	if (rport->flags & DISABLED) {
+		spin_unlock_irqrestore(&rport->lock, iflags);
+		DBGPV("returning: DISABLED\n");
+		return;
+	}
+	rport->flags |= HW_BUSY;
+	while (1) {
+		int swptr, hwptr, hw_avail, sw_avail, swidx;
+		vwsnd_port_hwstate_t hwstate = rport->hwstate;
+		vwsnd_port_swstate_t swstate = rport->swstate;
+
+		hwptr = li_read_hwptr(&rport->chan);
+		swptr = li_read_swptr(&rport->chan);
+		hw_avail = (hwptr - swptr + hwsize) % hwsize & -fragsize;
+		if (hw_avail > hwmax)
+			hw_avail = hwmax;
+		sw_avail = rport->swb_i_avail & -fragsize;
+		if (swstate != SW_RUN) {
+			DBGP("stopping.  hwstate = %d\n", hwstate);
+			if (hwstate != HW_STOPPED) {
+				li_deactivate_dma(&rport->chan);
+				rport->hwstate = HW_STOPPED;
+			}
+			wake_up(&rport->queue);
+			break;
+		}
+		if (!sw_avail || !hw_avail)
+			break;
+		spin_unlock_irqrestore(&rport->lock, iflags);
+
+		/*
+		 * We gave up the port lock, but we have the HW_BUSY flag.
+		 * Proceed without accessing any nonlocal state.
+		 * Do not exit the loop -- must check for more work.
+		 */
+
+		swidx = rport->swb_i_idx;
+		nb = hw_avail;
+		if (nb > sw_avail)
+			nb = sw_avail;
+		if (nb > hwsize - swptr)
+			nb = hwsize - swptr; /* don't overflow hwbuf */
+		if (nb > swsize - swidx)
+			nb = swsize - swidx; /* don't overflow swbuf */
+		ASSERT(nb > 0);
+		if (nb % fragsize) {
+			DBGP("nb = %d, fragsize = %d\n", nb, fragsize);
+			DBGP("hw_avail = %d\n", hw_avail);
+			DBGP("sw_avail = %d\n", sw_avail);
+			DBGP("hwsize = %d, swptr = %d\n", hwsize, swptr);
+			DBGP("swsize = %d, swidx = %d\n", swsize, swidx);
+		}
+		ASSERT(!(nb % fragsize));
+		DBGPV("copying hwb[%d..%d] to swb[%d..%d]\n",
+		      swptr, swptr + nb, swidx, swidx + nb);
+		pcm_copy_in(rport, swidx, swptr, nb);
+		li_write_swptr(&rport->chan, (swptr + nb) % hwsize);
+		spin_lock_irqsave(&rport->lock, iflags);
+		__swb_inc_i(rport, nb);
+		rport->byte_count += nb;
+		rport->frag_count += nb / fragsize;
+		ASSERT(nb % fragsize == 0);
+		wake_up(&rport->queue);
+	}
+	rport->flags &= ~HW_BUSY;
+	spin_unlock_irqrestore(&rport->lock, iflags);
+	DBGRV();
+}
+
+/*
+ * pcm_flush_frag() writes zero samples to fill the current fragment,
+ * then flushes it to the hardware.
+ *
+ * It is only meaningful to flush output, not input.
+ */
+
+static void pcm_flush_frag(vwsnd_dev_t *devc)
+{
+	vwsnd_port_t *wport = &devc->wport;
+
+	DBGPV("swstate = %d\n", wport->swstate);
+	if (wport->swstate == SW_RUN) {
+		int idx = wport->swb_u_idx;
+		int end = (idx + wport->hw_fragsize - 1)
+			>> wport->hw_fragshift
+			<< wport->hw_fragshift;
+		int nb = end - idx;
+		DBGPV("clearing %d bytes\n", nb);
+		if (nb)
+			memset(wport->swbuf + idx,
+			       (char) wport->zero_word,
+			       nb);
+		wport->swstate = SW_DRAIN;
+		pcm_output(devc, 0, nb);
+	}
+	DBGRV();
+}
+
+/*
+ * Wait for output to drain.  This sleeps uninterruptibly because
+ * there is nothing intelligent we can do if interrupted.  This
+ * means the process will be delayed in responding to the signal.
+ */
+
+static void pcm_write_sync(vwsnd_dev_t *devc)
+{
+	vwsnd_port_t *wport = &devc->wport;
+	DECLARE_WAITQUEUE(wait, current);
+	unsigned long flags;
+	vwsnd_port_hwstate_t hwstate;
+
+	DBGEV("(devc=0x%p)\n", devc);
+	add_wait_queue(&wport->queue, &wait);
+	while (1) {
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		spin_lock_irqsave(&wport->lock, flags);
+		{
+			hwstate = wport->hwstate;
+		}
+		spin_unlock_irqrestore(&wport->lock, flags);
+		if (hwstate == HW_STOPPED)
+			break;
+		schedule();
+	}
+	current->state = TASK_RUNNING;
+	remove_wait_queue(&wport->queue, &wait);
+	DBGPV("swstate = %d, hwstate = %d\n", wport->swstate, wport->hwstate);
+	DBGRV();
+}
+
+/*****************************************************************************/
+/* audio driver */
+
+/*
+ * seek on an audio device always fails.
+ */
+
+static void vwsnd_audio_read_intr(vwsnd_dev_t *devc, unsigned int status)
+{
+	int overflown = status & LI_INTR_COMM1_OVERFLOW;
+
+	if (status & READ_INTR_MASK)
+		pcm_input(devc, overflown, 0);
+}
+
+static void vwsnd_audio_write_intr(vwsnd_dev_t *devc, unsigned int status)
+{
+	int underflown = status & LI_INTR_COMM2_UNDERFLOW;
+
+	if (status & WRITE_INTR_MASK)
+		pcm_output(devc, underflown, 0);
+}
+
+static irqreturn_t vwsnd_audio_intr(int irq, void *dev_id, struct pt_regs *regs)
+{
+	vwsnd_dev_t *devc = (vwsnd_dev_t *) dev_id;
+	unsigned int status;
+
+	DBGEV("(irq=%d, dev_id=0x%p, regs=0x%p)\n", irq, dev_id, regs);
+
+	status = li_get_clear_intr_status(&devc->lith);
+	vwsnd_audio_read_intr(devc, status);
+	vwsnd_audio_write_intr(devc, status);
+	return IRQ_HANDLED;
+}
+
+static ssize_t vwsnd_audio_do_read(struct file *file,
+				   char *buffer,
+				   size_t count,
+				   loff_t *ppos)
+{
+	vwsnd_dev_t *devc = file->private_data;
+	vwsnd_port_t *rport = ((file->f_mode & FMODE_READ) ?
+			       &devc->rport : NULL);
+	int ret, nb;
+
+	DBGEV("(file=0x%p, buffer=0x%p, count=%d, ppos=0x%p)\n",
+	     file, buffer, count, ppos);
+
+	if (!rport)
+		return -EINVAL;
+
+	if (rport->swbuf == NULL) {
+		vwsnd_port_t *wport = (file->f_mode & FMODE_WRITE) ?
+			&devc->wport : NULL;
+		ret = pcm_setup(devc, rport, wport);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (!access_ok(VERIFY_READ, buffer, count))
+		return -EFAULT;
+	ret = 0;
+	while (count) {
+		DECLARE_WAITQUEUE(wait, current);
+		add_wait_queue(&rport->queue, &wait);
+		while ((nb = swb_inc_u(rport, 0)) == 0) {
+			DBGPV("blocking\n");
+			set_current_state(TASK_INTERRUPTIBLE);
+			if (rport->flags & DISABLED ||
+			    file->f_flags & O_NONBLOCK) {
+				current->state = TASK_RUNNING;
+				remove_wait_queue(&rport->queue, &wait);
+				return ret ? ret : -EAGAIN;
+			}
+			schedule();
+			if (signal_pending(current)) {
+				current->state = TASK_RUNNING;
+				remove_wait_queue(&rport->queue, &wait);
+				return ret ? ret : -ERESTARTSYS;
+			}
+		}
+		current->state = TASK_RUNNING;
+		remove_wait_queue(&rport->queue, &wait);
+		pcm_input(devc, 0, 0);
+		/* nb bytes are available in userbuf. */
+		if (nb > count)
+			nb = count;
+		DBGPV("nb = %d\n", nb);
+		if (copy_to_user(buffer, rport->swbuf + rport->swb_u_idx, nb))
+			return -EFAULT;
+		(void) swb_inc_u(rport, nb);
+		buffer += nb;
+		count -= nb;
+		ret += nb;
+	}
+	DBGPV("returning %d\n", ret);
+	return ret;
+}
+
+static ssize_t vwsnd_audio_read(struct file *file,
+				char *buffer,
+				size_t count,
+				loff_t *ppos)
+{
+	vwsnd_dev_t *devc = file->private_data;
+	ssize_t ret;
+
+	down(&devc->io_sema);
+	ret = vwsnd_audio_do_read(file, buffer, count, ppos);
+	up(&devc->io_sema);
+	return ret;
+}
+
+static ssize_t vwsnd_audio_do_write(struct file *file,
+				    const char *buffer,
+				    size_t count,
+				    loff_t *ppos)
+{
+	vwsnd_dev_t *devc = file->private_data;
+	vwsnd_port_t *wport = ((file->f_mode & FMODE_WRITE) ?
+			       &devc->wport : NULL);
+	int ret, nb;
+
+	DBGEV("(file=0x%p, buffer=0x%p, count=%d, ppos=0x%p)\n",
+	      file, buffer, count, ppos);
+
+	if (!wport)
+		return -EINVAL;
+
+	if (wport->swbuf == NULL) {
+		vwsnd_port_t *rport = (file->f_mode & FMODE_READ) ?
+			&devc->rport : NULL;
+		ret = pcm_setup(devc, rport, wport);
+		if (ret < 0)
+			return ret;
+	}
+	if (!access_ok(VERIFY_WRITE, buffer, count))
+		return -EFAULT;
+	ret = 0;
+	while (count) {
+		DECLARE_WAITQUEUE(wait, current);
+		add_wait_queue(&wport->queue, &wait);
+		while ((nb = swb_inc_u(wport, 0)) == 0) {
+			set_current_state(TASK_INTERRUPTIBLE);
+			if (wport->flags & DISABLED ||
+			    file->f_flags & O_NONBLOCK) {
+				current->state = TASK_RUNNING;
+				remove_wait_queue(&wport->queue, &wait);
+				return ret ? ret : -EAGAIN;
+			}
+			schedule();
+			if (signal_pending(current)) {
+				current->state = TASK_RUNNING;
+				remove_wait_queue(&wport->queue, &wait);
+				return ret ? ret : -ERESTARTSYS;
+			}
+		}
+		current->state = TASK_RUNNING;
+		remove_wait_queue(&wport->queue, &wait);
+		/* nb bytes are available in userbuf. */
+		if (nb > count)
+			nb = count;
+		DBGPV("nb = %d\n", nb);
+		if (copy_from_user(wport->swbuf + wport->swb_u_idx, buffer, nb))
+			return -EFAULT;
+		pcm_output(devc, 0, nb);
+		buffer += nb;
+		count -= nb;
+		ret += nb;
+	}
+	DBGPV("returning %d\n", ret);
+	return ret;
+}
+
+static ssize_t vwsnd_audio_write(struct file *file,
+				 const char *buffer,
+				 size_t count,
+				 loff_t *ppos)
+{
+	vwsnd_dev_t *devc = file->private_data;
+	ssize_t ret;
+
+	down(&devc->io_sema);
+	ret = vwsnd_audio_do_write(file, buffer, count, ppos);
+	up(&devc->io_sema);
+	return ret;
+}
+
+/* No kernel lock - fine */
+static unsigned int vwsnd_audio_poll(struct file *file,
+				     struct poll_table_struct *wait)
+{
+	vwsnd_dev_t *devc = (vwsnd_dev_t *) file->private_data;
+	vwsnd_port_t *rport = (file->f_mode & FMODE_READ) ?
+		&devc->rport : NULL;
+	vwsnd_port_t *wport = (file->f_mode & FMODE_WRITE) ?
+		&devc->wport : NULL;
+	unsigned int mask = 0;
+
+	DBGEV("(file=0x%p, wait=0x%p)\n", file, wait);
+
+	ASSERT(rport || wport);
+	if (rport) {
+		poll_wait(file, &rport->queue, wait);
+		if (swb_inc_u(rport, 0))
+			mask |= (POLLIN | POLLRDNORM);
+	}
+	if (wport) {
+		poll_wait(file, &wport->queue, wait);
+		if (wport->swbuf == NULL || swb_inc_u(wport, 0))
+			mask |= (POLLOUT | POLLWRNORM);
+	}
+
+	DBGPV("returning 0x%x\n", mask);
+	return mask;
+}
+
+static int vwsnd_audio_do_ioctl(struct inode *inode,
+				struct file *file,
+				unsigned int cmd,
+				unsigned long arg)
+{
+	vwsnd_dev_t *devc = (vwsnd_dev_t *) file->private_data;
+	vwsnd_port_t *rport = (file->f_mode & FMODE_READ) ?
+		&devc->rport : NULL;
+	vwsnd_port_t *wport = (file->f_mode & FMODE_WRITE) ?
+		&devc->wport : NULL;
+	vwsnd_port_t *aport = rport ? rport : wport;
+	struct audio_buf_info buf_info;
+	struct count_info info;
+	unsigned long flags;
+	int ival;
+
+	
+	DBGEV("(inode=0x%p, file=0x%p, cmd=0x%x, arg=0x%lx)\n",
+	      inode, file, cmd, arg);
+	switch (cmd) {
+	case OSS_GETVERSION:		/* _SIOR ('M', 118, int) */
+		DBGX("OSS_GETVERSION\n");
+		ival = SOUND_VERSION;
+		return put_user(ival, (int *) arg);
+
+	case SNDCTL_DSP_GETCAPS:	/* _SIOR ('P',15, int) */
+		DBGX("SNDCTL_DSP_GETCAPS\n");
+		ival = DSP_CAP_DUPLEX | DSP_CAP_REALTIME | DSP_CAP_TRIGGER;
+		return put_user(ival, (int *) arg);
+
+	case SNDCTL_DSP_GETFMTS:	/* _SIOR ('P',11, int) */
+		DBGX("SNDCTL_DSP_GETFMTS\n");
+		ival = (AFMT_S16_LE | AFMT_MU_LAW | AFMT_A_LAW |
+			AFMT_U8 | AFMT_S8);
+		return put_user(ival, (int *) arg);
+		break;
+
+	case SOUND_PCM_READ_RATE:	/* _SIOR ('P', 2, int) */
+		DBGX("SOUND_PCM_READ_RATE\n");
+		ival = aport->sw_framerate;
+		return put_user(ival, (int *) arg);
+
+	case SOUND_PCM_READ_CHANNELS:	/* _SIOR ('P', 6, int) */
+		DBGX("SOUND_PCM_READ_CHANNELS\n");
+		ival = aport->sw_channels;
+		return put_user(ival, (int *) arg);
+
+	case SNDCTL_DSP_SPEED:		/* _SIOWR('P', 2, int) */
+		if (get_user(ival, (int *) arg))
+			return -EFAULT;
+		DBGX("SNDCTL_DSP_SPEED %d\n", ival);
+		if (ival) {
+			if (aport->swstate != SW_INITIAL) {
+				DBGX("SNDCTL_DSP_SPEED failed: swstate = %d\n",
+				     aport->swstate);
+				return -EINVAL;
+			}
+			if (ival < MIN_SPEED)
+				ival = MIN_SPEED;
+			if (ival > MAX_SPEED)
+				ival = MAX_SPEED;
+			if (rport)
+				rport->sw_framerate = ival;
+			if (wport)
+				wport->sw_framerate = ival;
+		} else
+			ival = aport->sw_framerate;
+		return put_user(ival, (int *) arg);
+
+	case SNDCTL_DSP_STEREO:		/* _SIOWR('P', 3, int) */
+		if (get_user(ival, (int *) arg))
+			return -EFAULT;
+		DBGX("SNDCTL_DSP_STEREO %d\n", ival);
+		if (ival != 0 && ival != 1)
+			return -EINVAL;
+		if (aport->swstate != SW_INITIAL)
+			return -EINVAL;
+		if (rport)
+			rport->sw_channels = ival + 1;
+		if (wport)
+			wport->sw_channels = ival + 1;
+		return put_user(ival, (int *) arg);
+
+	case SNDCTL_DSP_CHANNELS:	/* _SIOWR('P', 6, int) */
+		if (get_user(ival, (int *) arg))
+			return -EFAULT;
+		DBGX("SNDCTL_DSP_CHANNELS %d\n", ival);
+		if (ival != 1 && ival != 2)
+			return -EINVAL;
+		if (aport->swstate != SW_INITIAL)
+			return -EINVAL;
+		if (rport)
+			rport->sw_channels = ival;
+		if (wport)
+			wport->sw_channels = ival;
+		return put_user(ival, (int *) arg);
+
+	case SNDCTL_DSP_GETBLKSIZE:	/* _SIOWR('P', 4, int) */
+		ival = pcm_setup(devc, rport, wport);
+		if (ival < 0) {
+			DBGX("SNDCTL_DSP_GETBLKSIZE failed, errno %d\n", ival);
+			return ival;
+		}
+		ival = 1 << aport->sw_fragshift;
+		DBGX("SNDCTL_DSP_GETBLKSIZE returning %d\n", ival);
+		return put_user(ival, (int *) arg);
+
+	case SNDCTL_DSP_SETFRAGMENT:	/* _SIOWR('P',10, int) */
+		if (get_user(ival, (int *) arg))
+			return -EFAULT;
+		DBGX("SNDCTL_DSP_SETFRAGMENT %d:%d\n",
+		     ival >> 16, ival & 0xFFFF);
+		if (aport->swstate != SW_INITIAL)
+			return -EINVAL;
+		{
+			int sw_fragshift = ival & 0xFFFF;
+			int sw_subdivshift = aport->sw_subdivshift;
+			int hw_fragshift = sw_fragshift - sw_subdivshift;
+			int sw_fragcount = (ival >> 16) & 0xFFFF;
+			int hw_fragsize;
+			if (hw_fragshift < MIN_FRAGSHIFT)
+				hw_fragshift = MIN_FRAGSHIFT;
+			if (hw_fragshift > MAX_FRAGSHIFT)
+				hw_fragshift = MAX_FRAGSHIFT;
+			sw_fragshift = hw_fragshift + aport->sw_subdivshift;
+			hw_fragsize = 1 << hw_fragshift;
+			if (sw_fragcount < MIN_FRAGCOUNT(hw_fragsize))
+				sw_fragcount = MIN_FRAGCOUNT(hw_fragsize);
+			if (sw_fragcount > MAX_FRAGCOUNT(hw_fragsize))
+				sw_fragcount = MAX_FRAGCOUNT(hw_fragsize);
+			DBGPV("sw_fragshift = %d\n", sw_fragshift);
+			DBGPV("rport = 0x%p, wport = 0x%p\n", rport, wport);
+			if (rport) {
+				rport->sw_fragshift = sw_fragshift;
+				rport->sw_fragcount = sw_fragcount;
+			}
+			if (wport) {
+				wport->sw_fragshift = sw_fragshift;
+				wport->sw_fragcount = sw_fragcount;
+			}
+			ival = sw_fragcount << 16 | sw_fragshift;
+		}
+		DBGX("SNDCTL_DSP_SETFRAGMENT returns %d:%d\n",
+		      ival >> 16, ival & 0xFFFF);
+		return put_user(ival, (int *) arg);
+
+	case SNDCTL_DSP_SUBDIVIDE:	/* _SIOWR('P', 9, int) */
+                if (get_user(ival, (int *) arg))
+			return -EFAULT;
+		DBGX("SNDCTL_DSP_SUBDIVIDE %d\n", ival);
+		if (aport->swstate != SW_INITIAL)
+			return -EINVAL;
+		{
+			int subdivshift;
+			int hw_fragshift, hw_fragsize, hw_fragcount;
+			switch (ival) {
+			case 1: subdivshift = 0; break;
+			case 2: subdivshift = 1; break;
+			case 4: subdivshift = 2; break;
+			default: return -EINVAL;
+			}
+			hw_fragshift = aport->sw_fragshift - subdivshift;
+			if (hw_fragshift < MIN_FRAGSHIFT ||
+			    hw_fragshift > MAX_FRAGSHIFT)
+				return -EINVAL;
+			hw_fragsize = 1 << hw_fragshift;
+			hw_fragcount = aport->sw_fragcount >> subdivshift;
+			if (hw_fragcount < MIN_FRAGCOUNT(hw_fragsize) ||
+			    hw_fragcount > MAX_FRAGCOUNT(hw_fragsize))
+				return -EINVAL;
+			if (rport)
+				rport->sw_subdivshift = subdivshift;
+			if (wport)
+				wport->sw_subdivshift = subdivshift;
+		}
+		return 0;
+
+	case SNDCTL_DSP_SETFMT:		/* _SIOWR('P',5, int) */
+		if (get_user(ival, (int *) arg))
+			return -EFAULT;
+		DBGX("SNDCTL_DSP_SETFMT %d\n", ival);
+		if (ival != AFMT_QUERY) {
+			if (aport->swstate != SW_INITIAL) {
+				DBGP("SETFMT failed, swstate = %d\n",
+				     aport->swstate);
+				return -EINVAL;
+			}
+			switch (ival) {
+			case AFMT_MU_LAW:
+			case AFMT_A_LAW:
+			case AFMT_U8:
+			case AFMT_S8:
+			case AFMT_S16_LE:
+				if (rport)
+					rport->sw_samplefmt = ival;
+				if (wport)
+					wport->sw_samplefmt = ival;
+				break;
+			default:
+				return -EINVAL;
+			}
+		}
+		ival = aport->sw_samplefmt;
+		return put_user(ival, (int *) arg);
+
+	case SNDCTL_DSP_GETOSPACE:	/* _SIOR ('P',12, audio_buf_info) */
+		DBGXV("SNDCTL_DSP_GETOSPACE\n");
+		if (!wport)
+			return -EINVAL;
+		ival = pcm_setup(devc, rport, wport);
+		if (ival < 0)
+			return ival;
+		ival = swb_inc_u(wport, 0);
+		buf_info.fragments = ival >> wport->sw_fragshift;
+		buf_info.fragstotal = wport->sw_fragcount;
+		buf_info.fragsize = 1 << wport->sw_fragshift;
+		buf_info.bytes = ival;
+		DBGXV("SNDCTL_DSP_GETOSPACE returns { %d %d %d %d }\n",
+		     buf_info.fragments, buf_info.fragstotal,
+		     buf_info.fragsize, buf_info.bytes);
+		if (copy_to_user((void *) arg, &buf_info, sizeof buf_info))
+			return -EFAULT;
+		return 0;
+
+	case SNDCTL_DSP_GETISPACE:	/* _SIOR ('P',13, audio_buf_info) */
+		DBGX("SNDCTL_DSP_GETISPACE\n");
+		if (!rport)
+			return -EINVAL;
+		ival = pcm_setup(devc, rport, wport);
+		if (ival < 0)
+			return ival;
+		ival = swb_inc_u(rport, 0);
+		buf_info.fragments = ival >> rport->sw_fragshift;
+		buf_info.fragstotal = rport->sw_fragcount;
+		buf_info.fragsize = 1 << rport->sw_fragshift;
+		buf_info.bytes = ival;
+		DBGX("SNDCTL_DSP_GETISPACE returns { %d %d %d %d }\n",
+		     buf_info.fragments, buf_info.fragstotal,
+		     buf_info.fragsize, buf_info.bytes);
+		if (copy_to_user((void *) arg, &buf_info, sizeof buf_info))
+			return -EFAULT;
+		return 0;
+
+	case SNDCTL_DSP_NONBLOCK:	/* _SIO  ('P',14) */
+		DBGX("SNDCTL_DSP_NONBLOCK\n");
+		file->f_flags |= O_NONBLOCK;
+		return 0;
+
+	case SNDCTL_DSP_RESET:		/* _SIO  ('P', 0) */
+		DBGX("SNDCTL_DSP_RESET\n");
+		/*
+		 * Nothing special needs to be done for input.  Input
+		 * samples sit in swbuf, but it will be reinitialized
+		 * to empty when pcm_setup() is called.
+		 */
+		if (wport && wport->swbuf) {
+			wport->swstate = SW_INITIAL;
+			pcm_output(devc, 0, 0);
+			pcm_write_sync(devc);
+		}
+		pcm_shutdown(devc, rport, wport);
+		return 0;
+
+	case SNDCTL_DSP_SYNC:		/* _SIO  ('P', 1) */
+		DBGX("SNDCTL_DSP_SYNC\n");
+		if (wport) {
+			pcm_flush_frag(devc);
+			pcm_write_sync(devc);
+		}
+		pcm_shutdown(devc, rport, wport);
+		return 0;
+
+	case SNDCTL_DSP_POST:		/* _SIO  ('P', 8) */
+		DBGX("SNDCTL_DSP_POST\n");
+		if (!wport)
+			return -EINVAL;
+		pcm_flush_frag(devc);
+		return 0;
+
+	case SNDCTL_DSP_GETIPTR:	/* _SIOR ('P', 17, count_info) */
+		DBGX("SNDCTL_DSP_GETIPTR\n");
+		if (!rport)
+			return -EINVAL;
+		spin_lock_irqsave(&rport->lock, flags);
+		{
+			ustmsc_t ustmsc;
+			if (rport->hwstate == HW_RUNNING) {
+				ASSERT(rport->swstate == SW_RUN);
+				li_read_USTMSC(&rport->chan, &ustmsc);
+				info.bytes = ustmsc.msc - rport->MSC_offset;
+				info.bytes *= rport->frame_size;
+			} else {
+				info.bytes = rport->byte_count;
+			}
+			info.blocks = rport->frag_count;
+			info.ptr = 0;	/* not implemented */
+			rport->frag_count = 0;
+		}
+		spin_unlock_irqrestore(&rport->lock, flags);
+		if (copy_to_user((void *) arg, &info, sizeof info))
+			return -EFAULT;
+		return 0;
+
+	case SNDCTL_DSP_GETOPTR:	/* _SIOR ('P',18, count_info) */
+		DBGX("SNDCTL_DSP_GETOPTR\n");
+		if (!wport)
+			return -EINVAL;
+		spin_lock_irqsave(&wport->lock, flags);
+		{
+			ustmsc_t ustmsc;
+			if (wport->hwstate == HW_RUNNING) {
+				ASSERT(wport->swstate == SW_RUN);
+				li_read_USTMSC(&wport->chan, &ustmsc);
+				info.bytes = ustmsc.msc - wport->MSC_offset;
+				info.bytes *= wport->frame_size;
+			} else {
+				info.bytes = wport->byte_count;
+			}
+			info.blocks = wport->frag_count;
+			info.ptr = 0;	/* not implemented */
+			wport->frag_count = 0;
+		}
+		spin_unlock_irqrestore(&wport->lock, flags);
+		if (copy_to_user((void *) arg, &info, sizeof info))
+			return -EFAULT;
+		return 0;
+
+	case SNDCTL_DSP_GETODELAY:	/* _SIOR ('P', 23, int) */
+		DBGX("SNDCTL_DSP_GETODELAY\n");
+		if (!wport)
+			return -EINVAL;
+		spin_lock_irqsave(&wport->lock, flags);
+		{
+			int fsize = wport->frame_size;
+			ival = wport->swb_i_avail / fsize;
+			if (wport->hwstate == HW_RUNNING) {
+				int swptr, hwptr, hwframes, hwbytes, hwsize;
+				int totalhwbytes;
+				ustmsc_t ustmsc;
+
+				hwsize = wport->hwbuf_size;
+				swptr = li_read_swptr(&wport->chan);
+				li_read_USTMSC(&wport->chan, &ustmsc);
+				hwframes = ustmsc.msc - wport->MSC_offset;
+				totalhwbytes = hwframes * fsize;
+				hwptr = totalhwbytes % hwsize;
+				hwbytes = (swptr - hwptr + hwsize) % hwsize;
+				ival += hwbytes / fsize;
+			}
+		}
+		spin_unlock_irqrestore(&wport->lock, flags);
+		return put_user(ival, (int *) arg);
+
+	case SNDCTL_DSP_PROFILE:	/* _SIOW ('P', 23, int) */
+		DBGX("SNDCTL_DSP_PROFILE\n");
+
+		/*
+		 * Thomas Sailer explains SNDCTL_DSP_PROFILE
+		 * (private email, March 24, 1999):
+		 *
+		 *     This gives the sound driver a hint on what it
+		 *     should do with partial fragments
+		 *     (i.e. fragments partially filled with write).
+		 *     This can direct the driver to zero them or
+		 *     leave them alone.  But don't ask me what this
+		 *     is good for, my driver just zeroes the last
+		 *     fragment before the receiver stops, no idea
+		 *     what good for any other behaviour could
+		 *     be. Implementing it as NOP seems safe.
+		 */
+
+		break;
+
+	case SNDCTL_DSP_GETTRIGGER:	/* _SIOR ('P',16, int) */
+		DBGX("SNDCTL_DSP_GETTRIGGER\n");
+		ival = 0;
+		if (rport) {
+			spin_lock_irqsave(&rport->lock, flags);
+			{
+				if (!(rport->flags & DISABLED))
+					ival |= PCM_ENABLE_INPUT;
+			}
+			spin_unlock_irqrestore(&rport->lock, flags);
+		}
+		if (wport) {
+			spin_lock_irqsave(&wport->lock, flags);
+			{
+				if (!(wport->flags & DISABLED))
+					ival |= PCM_ENABLE_OUTPUT;
+			}
+			spin_unlock_irqrestore(&wport->lock, flags);
+		}
+		return put_user(ival, (int *) arg);
+
+	case SNDCTL_DSP_SETTRIGGER:	/* _SIOW ('P',16, int) */
+		if (get_user(ival, (int *) arg))
+			return -EFAULT;
+		DBGX("SNDCTL_DSP_SETTRIGGER %d\n", ival);
+
+		/*
+		 * If user is disabling I/O and port is not in initial
+		 * state, fail with EINVAL.
+		 */
+
+		if (((rport && !(ival & PCM_ENABLE_INPUT)) ||
+		     (wport && !(ival & PCM_ENABLE_OUTPUT))) &&
+		    aport->swstate != SW_INITIAL)
+			return -EINVAL;
+
+		if (rport) {
+			vwsnd_port_hwstate_t hwstate;
+			spin_lock_irqsave(&rport->lock, flags);
+			{
+				hwstate = rport->hwstate;
+				if (ival & PCM_ENABLE_INPUT)
+					rport->flags &= ~DISABLED;
+				else
+					rport->flags |= DISABLED;
+			}
+			spin_unlock_irqrestore(&rport->lock, flags);
+			if (hwstate != HW_RUNNING && ival & PCM_ENABLE_INPUT) {
+
+				if (rport->swstate == SW_INITIAL)
+					pcm_setup(devc, rport, wport);
+				else
+					li_activate_dma(&rport->chan);
+			}
+		}
+		if (wport) {
+			vwsnd_port_flags_t pflags;
+			spin_lock_irqsave(&wport->lock, flags);
+			{
+				pflags = wport->flags;
+				if (ival & PCM_ENABLE_OUTPUT)
+					wport->flags &= ~DISABLED;
+				else
+					wport->flags |= DISABLED;
+			}
+			spin_unlock_irqrestore(&wport->lock, flags);
+			if (pflags & DISABLED && ival & PCM_ENABLE_OUTPUT) {
+				if (wport->swstate == SW_RUN)
+					pcm_output(devc, 0, 0);
+			}
+		}
+		return 0;
+
+	default:
+		DBGP("unknown ioctl 0x%x\n", cmd);
+		return -EINVAL;
+	}
+	DBGP("unimplemented ioctl 0x%x\n", cmd);
+	return -EINVAL;
+}
+
+static int vwsnd_audio_ioctl(struct inode *inode,
+				struct file *file,
+				unsigned int cmd,
+				unsigned long arg)
+{
+	vwsnd_dev_t *devc = (vwsnd_dev_t *) file->private_data;
+	int ret;
+
+	down(&devc->io_sema);
+	ret = vwsnd_audio_do_ioctl(inode, file, cmd, arg);
+	up(&devc->io_sema);
+	return ret;
+}
+
+/* No mmap. */
+
+static int vwsnd_audio_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	DBGE("(file=0x%p, vma=0x%p)\n", file, vma);
+	return -ENODEV;
+}
+
+/*
+ * Open the audio device for read and/or write.
+ *
+ * Returns 0 on success, -errno on failure.
+ */
+
+static int vwsnd_audio_open(struct inode *inode, struct file *file)
+{
+	vwsnd_dev_t *devc;
+	int minor = iminor(inode);
+	int sw_samplefmt;
+
+	DBGE("(inode=0x%p, file=0x%p)\n", inode, file);
+
+	INC_USE_COUNT;
+	for (devc = vwsnd_dev_list; devc; devc = devc->next_dev)
+		if ((devc->audio_minor & ~0x0F) == (minor & ~0x0F))
+			break;
+
+	if (devc == NULL) {
+		DEC_USE_COUNT;
+		return -ENODEV;
+	}
+
+	down(&devc->open_sema);
+	while (devc->open_mode & file->f_mode) {
+		up(&devc->open_sema);
+		if (file->f_flags & O_NONBLOCK) {
+			DEC_USE_COUNT;
+			return -EBUSY;
+		}
+		interruptible_sleep_on(&devc->open_wait);
+		if (signal_pending(current)) {
+			DEC_USE_COUNT;
+			return -ERESTARTSYS;
+		}
+		down(&devc->open_sema);
+	}
+	devc->open_mode |= file->f_mode & (FMODE_READ | FMODE_WRITE);
+	up(&devc->open_sema);
+
+	/* get default sample format from minor number. */
+
+	sw_samplefmt = 0;
+	if ((minor & 0xF) == SND_DEV_DSP)
+		sw_samplefmt = AFMT_U8;
+	else if ((minor & 0xF) == SND_DEV_AUDIO)
+		sw_samplefmt = AFMT_MU_LAW;
+	else if ((minor & 0xF) == SND_DEV_DSP16)
+		sw_samplefmt = AFMT_S16_LE;
+	else
+		ASSERT(0);
+
+	/* Initialize vwsnd_ports. */
+
+	down(&devc->io_sema);
+	{
+		if (file->f_mode & FMODE_READ) {
+			devc->rport.swstate        = SW_INITIAL;
+			devc->rport.flags          = 0;
+			devc->rport.sw_channels    = 1;
+			devc->rport.sw_samplefmt   = sw_samplefmt;
+			devc->rport.sw_framerate   = 8000;
+			devc->rport.sw_fragshift   = DEFAULT_FRAGSHIFT;
+			devc->rport.sw_fragcount   = DEFAULT_FRAGCOUNT;
+			devc->rport.sw_subdivshift = DEFAULT_SUBDIVSHIFT;
+			devc->rport.byte_count     = 0;
+			devc->rport.frag_count     = 0;
+		}
+		if (file->f_mode & FMODE_WRITE) {
+			devc->wport.swstate        = SW_INITIAL;
+			devc->wport.flags          = 0;
+			devc->wport.sw_channels    = 1;
+			devc->wport.sw_samplefmt   = sw_samplefmt;
+			devc->wport.sw_framerate   = 8000;
+			devc->wport.sw_fragshift   = DEFAULT_FRAGSHIFT;
+			devc->wport.sw_fragcount   = DEFAULT_FRAGCOUNT;
+			devc->wport.sw_subdivshift = DEFAULT_SUBDIVSHIFT;
+			devc->wport.byte_count     = 0;
+			devc->wport.frag_count     = 0;
+		}
+	}
+	up(&devc->io_sema);
+
+	file->private_data = devc;
+	DBGRV();
+	return 0;
+}
+
+/*
+ * Release (close) the audio device.
+ */
+
+static int vwsnd_audio_release(struct inode *inode, struct file *file)
+{
+	vwsnd_dev_t *devc = (vwsnd_dev_t *) file->private_data;
+	vwsnd_port_t *wport = NULL, *rport = NULL;
+	int err = 0;
+
+	lock_kernel();
+	down(&devc->io_sema);
+	{
+		DBGEV("(inode=0x%p, file=0x%p)\n", inode, file);
+
+		if (file->f_mode & FMODE_READ)
+			rport = &devc->rport;
+		if (file->f_mode & FMODE_WRITE) {
+			wport = &devc->wport;
+			pcm_flush_frag(devc);
+			pcm_write_sync(devc);
+		}
+		pcm_shutdown(devc, rport, wport);
+		if (rport)
+			rport->swstate = SW_OFF;
+		if (wport)
+			wport->swstate = SW_OFF;
+	}
+	up(&devc->io_sema);
+
+	down(&devc->open_sema);
+	{
+		devc->open_mode &= ~file->f_mode;
+	}
+	up(&devc->open_sema);
+	wake_up(&devc->open_wait);
+	DEC_USE_COUNT;
+	DBGR();
+	unlock_kernel();
+	return err;
+}
+
+static struct file_operations vwsnd_audio_fops = {
+	.owner =	THIS_MODULE,
+	.llseek =	no_llseek,
+	.read =		vwsnd_audio_read,
+	.write =	vwsnd_audio_write,
+	.poll =		vwsnd_audio_poll,
+	.ioctl =	vwsnd_audio_ioctl,
+	.mmap =		vwsnd_audio_mmap,
+	.open =		vwsnd_audio_open,
+	.release =	vwsnd_audio_release,
+};
+
+/*****************************************************************************/
+/* mixer driver */
+
+/* open the mixer device. */
+
+static int vwsnd_mixer_open(struct inode *inode, struct file *file)
+{
+	vwsnd_dev_t *devc;
+
+	DBGEV("(inode=0x%p, file=0x%p)\n", inode, file);
+
+	INC_USE_COUNT;
+	for (devc = vwsnd_dev_list; devc; devc = devc->next_dev)
+		if (devc->mixer_minor == iminor(inode))
+			break;
+
+	if (devc == NULL) {
+		DEC_USE_COUNT;
+		return -ENODEV;
+	}
+	file->private_data = devc;
+	return 0;
+}
+
+/* release (close) the mixer device. */
+
+static int vwsnd_mixer_release(struct inode *inode, struct file *file)
+{
+	DBGEV("(inode=0x%p, file=0x%p)\n", inode, file);
+	DEC_USE_COUNT;
+	return 0;
+}
+
+/* mixer_read_ioctl handles all read ioctls on the mixer device. */
+
+static int mixer_read_ioctl(vwsnd_dev_t *devc, unsigned int nr, void __user *arg)
+{
+	int val = -1;
+
+	DBGEV("(devc=0x%p, nr=0x%x, arg=0x%p)\n", devc, nr, arg);
+
+	switch (nr) {
+	case SOUND_MIXER_CAPS:
+		val = SOUND_CAP_EXCL_INPUT;
+		break;
+
+	case SOUND_MIXER_DEVMASK:
+		val = (SOUND_MASK_PCM | SOUND_MASK_LINE |
+		       SOUND_MASK_MIC | SOUND_MASK_CD | SOUND_MASK_RECLEV);
+		break;
+
+	case SOUND_MIXER_STEREODEVS:
+		val = (SOUND_MASK_PCM | SOUND_MASK_LINE |
+		       SOUND_MASK_MIC | SOUND_MASK_CD | SOUND_MASK_RECLEV);
+		break;
+
+	case SOUND_MIXER_OUTMASK:
+		val = (SOUND_MASK_PCM | SOUND_MASK_LINE |
+		       SOUND_MASK_MIC | SOUND_MASK_CD);
+		break;
+
+	case SOUND_MIXER_RECMASK:
+		val = (SOUND_MASK_PCM | SOUND_MASK_LINE |
+		       SOUND_MASK_MIC | SOUND_MASK_CD);
+		break;
+
+	case SOUND_MIXER_PCM:
+		val = ad1843_get_gain(&devc->lith, &ad1843_gain_PCM);
+		break;
+
+	case SOUND_MIXER_LINE:
+		val = ad1843_get_gain(&devc->lith, &ad1843_gain_LINE);
+		break;
+
+	case SOUND_MIXER_MIC:
+		val = ad1843_get_gain(&devc->lith, &ad1843_gain_MIC);
+		break;
+
+	case SOUND_MIXER_CD:
+		val = ad1843_get_gain(&devc->lith, &ad1843_gain_CD);
+		break;
+
+	case SOUND_MIXER_RECLEV:
+		val = ad1843_get_gain(&devc->lith, &ad1843_gain_RECLEV);
+		break;
+
+	case SOUND_MIXER_RECSRC:
+		val = ad1843_get_recsrc(&devc->lith);
+		break;
+
+	case SOUND_MIXER_OUTSRC:
+		val = ad1843_get_outsrc(&devc->lith);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+	return put_user(val, (int __user *) arg);
+}
+
+/* mixer_write_ioctl handles all write ioctls on the mixer device. */
+
+static int mixer_write_ioctl(vwsnd_dev_t *devc, unsigned int nr, void __user *arg)
+{
+	int val;
+	int err;
+
+	DBGEV("(devc=0x%p, nr=0x%x, arg=0x%p)\n", devc, nr, arg);
+
+	err = get_user(val, (int __user *) arg);
+	if (err)
+		return -EFAULT;
+	switch (nr) {
+	case SOUND_MIXER_PCM:
+		val = ad1843_set_gain(&devc->lith, &ad1843_gain_PCM, val);
+		break;
+
+	case SOUND_MIXER_LINE:
+		val = ad1843_set_gain(&devc->lith, &ad1843_gain_LINE, val);
+		break;
+
+	case SOUND_MIXER_MIC:
+		val = ad1843_set_gain(&devc->lith, &ad1843_gain_MIC, val);
+		break;
+
+	case SOUND_MIXER_CD:
+		val = ad1843_set_gain(&devc->lith, &ad1843_gain_CD, val);
+		break;
+
+	case SOUND_MIXER_RECLEV:
+		val = ad1843_set_gain(&devc->lith, &ad1843_gain_RECLEV, val);
+		break;
+
+	case SOUND_MIXER_RECSRC:
+		if (devc->rport.swbuf || devc->wport.swbuf)
+			return -EBUSY;	/* can't change recsrc while running */
+		val = ad1843_set_recsrc(&devc->lith, val);
+		break;
+
+	case SOUND_MIXER_OUTSRC:
+		val = ad1843_set_outsrc(&devc->lith, val);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+	if (val < 0)
+		return val;
+	return put_user(val, (int __user *) arg);
+}
+
+/* This is the ioctl entry to the mixer driver. */
+
+static int vwsnd_mixer_ioctl(struct inode *ioctl,
+			      struct file *file,
+			      unsigned int cmd,
+			      unsigned long arg)
+{
+	vwsnd_dev_t *devc = (vwsnd_dev_t *) file->private_data;
+	const unsigned int nrmask = _IOC_NRMASK << _IOC_NRSHIFT;
+	const unsigned int nr = (cmd & nrmask) >> _IOC_NRSHIFT;
+	int retval;
+
+	DBGEV("(devc=0x%p, cmd=0x%x, arg=0x%lx)\n", devc, cmd, arg);
+
+	down(&devc->mix_sema);
+	{
+		if ((cmd & ~nrmask) == MIXER_READ(0))
+			retval = mixer_read_ioctl(devc, nr, (void __user *) arg);
+		else if ((cmd & ~nrmask) == MIXER_WRITE(0))
+			retval = mixer_write_ioctl(devc, nr, (void __user *) arg);
+		else
+			retval = -EINVAL;
+	}
+	up(&devc->mix_sema);
+	return retval;
+}
+
+static struct file_operations vwsnd_mixer_fops = {
+	.owner =	THIS_MODULE,
+	.llseek =	no_llseek,
+	.ioctl =	vwsnd_mixer_ioctl,
+	.open =		vwsnd_mixer_open,
+	.release =	vwsnd_mixer_release,
+};
+
+/*****************************************************************************/
+/* probe/attach/unload */
+
+/* driver probe routine.  Return nonzero if hardware is found. */
+
+static int __init probe_vwsnd(struct address_info *hw_config)
+{
+	lithium_t lith;
+	int w;
+	unsigned long later;
+
+	DBGEV("(hw_config=0x%p)\n", hw_config);
+
+	/* XXX verify lithium present (to prevent crash on non-vw) */
+
+	if (li_create(&lith, hw_config->io_base) != 0) {
+		printk(KERN_WARNING "probe_vwsnd: can't map lithium\n");
+		return 0;
+	}
+	later = jiffies + 2;
+	li_writel(&lith, LI_HOST_CONTROLLER, LI_HC_LINK_ENABLE);
+	do {
+		w = li_readl(&lith, LI_HOST_CONTROLLER);
+	} while (w == LI_HC_LINK_ENABLE && time_before(jiffies, later));
+	
+	li_destroy(&lith);
+
+	DBGPV("HC = 0x%04x\n", w);
+
+	if ((w == LI_HC_LINK_ENABLE) || (w & LI_HC_LINK_CODEC)) {
+
+		/* This may indicate a beta machine with no audio,
+		 * or a future machine with different audio.
+		 * On beta-release 320 w/ no audio, HC == 0x4000 */
+
+		printk(KERN_WARNING "probe_vwsnd: audio codec not found\n");
+		return 0;
+	}
+
+	if (w & LI_HC_LINK_FAILURE) {
+		printk(KERN_WARNING "probe_vwsnd: can't init audio codec\n");
+		return 0;
+	}
+
+	printk(KERN_INFO "vwsnd: lithium audio at mmio %#x irq %d\n",
+		hw_config->io_base, hw_config->irq);
+
+	return 1;
+}
+
+/*
+ * driver attach routine.  Initialize driver data structures and
+ * initialize hardware.  A new vwsnd_dev_t is allocated and put
+ * onto the global list, vwsnd_dev_list.
+ *
+ * Return +minor_dev on success, -errno on failure.
+ */
+
+static int __init attach_vwsnd(struct address_info *hw_config)
+{
+	vwsnd_dev_t *devc = NULL;
+	int err = -ENOMEM;
+
+	DBGEV("(hw_config=0x%p)\n", hw_config);
+
+	devc = kmalloc(sizeof (vwsnd_dev_t), GFP_KERNEL);
+	if (devc == NULL)
+		goto fail0;
+
+	err = li_create(&devc->lith, hw_config->io_base);
+	if (err)
+		goto fail1;
+
+	init_waitqueue_head(&devc->open_wait);
+
+	devc->rport.hwbuf_size = HWBUF_SIZE;
+	devc->rport.hwbuf_vaddr = __get_free_pages(GFP_KERNEL, HWBUF_ORDER);
+	if (!devc->rport.hwbuf_vaddr)
+		goto fail2;
+	devc->rport.hwbuf = (void *) devc->rport.hwbuf_vaddr;
+	devc->rport.hwbuf_paddr = virt_to_phys(devc->rport.hwbuf);
+
+	/*
+	 * Quote from the NT driver:
+	 *
+	 * // WARNING!!! HACK to setup output dma!!!
+	 * // This is required because even on output there is some data
+	 * // trickling into the input DMA channel.  This is a bug in the
+	 * // Lithium microcode.
+	 * // --sde
+	 *
+	 * We set the input side's DMA base address here.  It will remain
+	 * valid until the driver is unloaded.
+	 */
+
+	li_writel(&devc->lith, LI_COMM1_BASE,
+		  devc->rport.hwbuf_paddr >> 8 | 1 << (37 - 8));
+
+	devc->wport.hwbuf_size = HWBUF_SIZE;
+	devc->wport.hwbuf_vaddr = __get_free_pages(GFP_KERNEL, HWBUF_ORDER);
+	if (!devc->wport.hwbuf_vaddr)
+		goto fail3;
+	devc->wport.hwbuf = (void *) devc->wport.hwbuf_vaddr;
+	devc->wport.hwbuf_paddr = virt_to_phys(devc->wport.hwbuf);
+	DBGP("wport hwbuf = 0x%p\n", devc->wport.hwbuf);
+
+	DBGDO(shut_up++);
+	err = ad1843_init(&devc->lith);
+	DBGDO(shut_up--);
+	if (err)
+		goto fail4;
+
+	/* install interrupt handler */
+
+	err = request_irq(hw_config->irq, vwsnd_audio_intr, 0, "vwsnd", devc);
+	if (err)
+		goto fail5;
+
+	/* register this device's drivers. */
+
+	devc->audio_minor = register_sound_dsp(&vwsnd_audio_fops, -1);
+	if ((err = devc->audio_minor) < 0) {
+		DBGDO(printk(KERN_WARNING
+			     "attach_vwsnd: register_sound_dsp error %d\n",
+			     err));
+		goto fail6;
+	}
+	devc->mixer_minor = register_sound_mixer(&vwsnd_mixer_fops,
+						 devc->audio_minor >> 4);
+	if ((err = devc->mixer_minor) < 0) {
+		DBGDO(printk(KERN_WARNING
+			     "attach_vwsnd: register_sound_mixer error %d\n",
+			     err));
+		goto fail7;
+	}
+
+	/* Squirrel away device indices for unload routine. */
+
+	hw_config->slots[0] = devc->audio_minor;
+
+	/* Initialize as much of *devc as possible */
+
+	init_MUTEX(&devc->open_sema);
+	init_MUTEX(&devc->io_sema);
+	init_MUTEX(&devc->mix_sema);
+	devc->open_mode = 0;
+	spin_lock_init(&devc->rport.lock);
+	init_waitqueue_head(&devc->rport.queue);
+	devc->rport.swstate = SW_OFF;
+	devc->rport.hwstate = HW_STOPPED;
+	devc->rport.flags = 0;
+	devc->rport.swbuf = NULL;
+	spin_lock_init(&devc->wport.lock);
+	init_waitqueue_head(&devc->wport.queue);
+	devc->wport.swstate = SW_OFF;
+	devc->wport.hwstate = HW_STOPPED;
+	devc->wport.flags = 0;
+	devc->wport.swbuf = NULL;
+
+	/* Success.  Link us onto the local device list. */
+
+	devc->next_dev = vwsnd_dev_list;
+	vwsnd_dev_list = devc;
+	return devc->audio_minor;
+
+	/* So many ways to fail.  Undo what we did. */
+
+ fail7:
+	unregister_sound_dsp(devc->audio_minor);
+ fail6:
+	free_irq(hw_config->irq, devc);
+ fail5:
+ fail4:
+	free_pages(devc->wport.hwbuf_vaddr, HWBUF_ORDER);
+ fail3:
+	free_pages(devc->rport.hwbuf_vaddr, HWBUF_ORDER);
+ fail2:
+	li_destroy(&devc->lith);
+ fail1:
+	kfree(devc);
+ fail0:
+	return err;
+}
+
+static int __exit unload_vwsnd(struct address_info *hw_config)
+{
+	vwsnd_dev_t *devc, **devcp;
+
+	DBGE("()\n");
+
+	devcp = &vwsnd_dev_list;
+	while ((devc = *devcp)) {
+		if (devc->audio_minor == hw_config->slots[0]) {
+			*devcp = devc->next_dev;
+			break;
+		}
+		devcp = &devc->next_dev;
+	}
+
+	if (!devc)
+		return -ENODEV;
+
+	unregister_sound_mixer(devc->mixer_minor);
+	unregister_sound_dsp(devc->audio_minor);
+	free_irq(hw_config->irq, devc);
+	free_pages(devc->wport.hwbuf_vaddr, HWBUF_ORDER);
+	free_pages(devc->rport.hwbuf_vaddr, HWBUF_ORDER);
+	li_destroy(&devc->lith);
+	kfree(devc);
+
+	return 0;
+}
+
+/*****************************************************************************/
+/* initialization and loadable kernel module interface */
+
+static struct address_info the_hw_config = {
+	0xFF001000,			/* lithium phys addr  */
+	CO_IRQ(CO_APIC_LI_AUDIO)	/* irq */
+};
+
+MODULE_DESCRIPTION("SGI Visual Workstation sound module");
+MODULE_AUTHOR("Bob Miller <kbob@sgi.com>");
+MODULE_LICENSE("GPL");
+
+static int __init init_vwsnd(void)
+{
+	int err;
+
+	DBGXV("\n");
+	DBGXV("sound::vwsnd::init_module()\n");
+
+	if (!probe_vwsnd(&the_hw_config))
+		return -ENODEV;
+
+	err = attach_vwsnd(&the_hw_config);
+	if (err < 0)
+		return err;
+	return 0;
+}
+
+static void __exit cleanup_vwsnd(void)
+{
+	DBGX("sound::vwsnd::cleanup_module()\n");
+
+	unload_vwsnd(&the_hw_config);
+}
+
+module_init(init_vwsnd);
+module_exit(cleanup_vwsnd);