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, 648 insertions, 0 deletions

diff --git a/arch/m68k/atari/ataints.c b/arch/m68k/atari/ataints.c
new file mode 100644
index 00000000000..076f4791784
--- /dev/null
+++ b/arch/m68k/atari/ataints.c
@@ -0,0 +1,648 @@
+/*
+ * arch/m68k/atari/ataints.c -- Atari Linux interrupt handling code
+ *
+ * 5/2/94 Roman Hodek:
+ *  Added support for TT interrupts; setup for TT SCU (may someone has
+ *  twiddled there and we won't get the right interrupts :-()
+ *
+ *  Major change: The device-independent code in m68k/ints.c didn't know
+ *  about non-autovec ints yet. It hardcoded the number of possible ints to
+ *  7 (IRQ1...IRQ7). But the Atari has lots of non-autovec ints! I made the
+ *  number of possible ints a constant defined in interrupt.h, which is
+ *  47 for the Atari. So we can call request_irq() for all Atari interrupts
+ *  just the normal way. Additionally, all vectors >= 48 are initialized to
+ *  call trap() instead of inthandler(). This must be changed here, too.
+ *
+ * 1995-07-16 Lars Brinkhoff <f93labr@dd.chalmers.se>:
+ *  Corrected a bug in atari_add_isr() which rejected all SCC
+ *  interrupt sources if there were no TT MFP!
+ *
+ * 12/13/95: New interface functions atari_level_triggered_int() and
+ *  atari_register_vme_int() as support for level triggered VME interrupts.
+ *
+ * 02/12/96: (Roman)
+ *  Total rewrite of Atari interrupt handling, for new scheme see comments
+ *  below.
+ *
+ * 1996-09-03 lars brinkhoff <f93labr@dd.chalmers.se>:
+ *  Added new function atari_unregister_vme_int(), and
+ *  modified atari_register_vme_int() as well as IS_VALID_INTNO()
+ *  to work with it.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/kernel_stat.h>
+#include <linux/init.h>
+#include <linux/seq_file.h>
+
+#include <asm/system.h>
+#include <asm/traps.h>
+
+#include <asm/atarihw.h>
+#include <asm/atariints.h>
+#include <asm/atari_stdma.h>
+#include <asm/irq.h>
+#include <asm/entry.h>
+
+
+/*
+ * Atari interrupt handling scheme:
+ * --------------------------------
+ *
+ * All interrupt source have an internal number (defined in
+ * <asm/atariints.h>): Autovector interrupts are 1..7, then follow ST-MFP,
+ * TT-MFP, SCC, and finally VME interrupts. Vector numbers for the latter can
+ * be allocated by atari_register_vme_int().
+ *
+ * Each interrupt can be of three types:
+ *
+ *  - SLOW: The handler runs with all interrupts enabled, except the one it
+ *    was called by (to avoid reentering). This should be the usual method.
+ *    But it is currently possible only for MFP ints, since only the MFP
+ *    offers an easy way to mask interrupts.
+ *
+ *  - FAST: The handler runs with all interrupts disabled. This should be used
+ *    only for really fast handlers, that just do actions immediately
+ *    necessary, and let the rest do a bottom half or task queue.
+ *
+ *  - PRIORITIZED: The handler can be interrupted by higher-level ints
+ *    (greater IPL, no MFP priorities!). This is the method of choice for ints
+ *    which should be slow, but are not from a MFP.
+ *
+ * The feature of more than one handler for one int source is still there, but
+ * only applicable if all handers are of the same type. To not slow down
+ * processing of ints with only one handler by the chaining feature, the list
+ * calling function atari_call_irq_list() is only plugged in at the time the
+ * second handler is registered.
+ *
+ * Implementation notes: For fast-as-possible int handling, there are separate
+ * entry points for each type (slow/fast/prio). The assembler handler calls
+ * the irq directly in the usual case, no C wrapper is involved. In case of
+ * multiple handlers, atari_call_irq_list() is registered as handler and calls
+ * in turn the real irq's. To ease access from assembler level to the irq
+ * function pointer and accompanying data, these two are stored in a separate
+ * array, irq_handler[]. The rest of data (type, name) are put into a second
+ * array, irq_param, that is accessed from C only. For each slow interrupt (32
+ * in all) there are separate handler functions, which makes it possible to
+ * hard-code the MFP register address and value, are necessary to mask the
+ * int. If there'd be only one generic function, lots of calculations would be
+ * needed to determine MFP register and int mask from the vector number :-(
+ *
+ * Furthermore, slow ints may not lower the IPL below its previous value
+ * (before the int happened). This is needed so that an int of class PRIO, on
+ * that this int may be stacked, cannot be reentered. This feature is
+ * implemented as follows: If the stack frame format is 1 (throwaway), the int
+ * is not stacked, and the IPL is anded with 0xfbff, resulting in a new level
+ * 2, which still blocks the HSYNC, but no interrupts of interest. If the
+ * frame format is 0, the int is nested, and the old IPL value can be found in
+ * the sr copy in the frame.
+ */
+
+
+#define	NUM_INT_SOURCES	(8 + NUM_ATARI_SOURCES)
+
+typedef void (*asm_irq_handler)(void);
+
+struct irqhandler {
+	irqreturn_t (*handler)(int, void *, struct pt_regs *);
+	void	*dev_id;
+};
+
+struct irqparam {
+	unsigned long	flags;
+	const char	*devname;
+};
+
+/*
+ * Array with irq's and their parameter data. This array is accessed from low
+ * level assembler code, so an element size of 8 allows usage of index scaling
+ * addressing mode.
+ */
+static struct irqhandler irq_handler[NUM_INT_SOURCES];
+
+/*
+ * This array hold the rest of parameters of int handlers: type
+ * (slow,fast,prio) and the name of the handler. These values are only
+ * accessed from C
+ */
+static struct irqparam irq_param[NUM_INT_SOURCES];
+
+/*
+ * Bitmap for free interrupt vector numbers
+ * (new vectors starting from 0x70 can be allocated by
+ * atari_register_vme_int())
+ */
+static int free_vme_vec_bitmap;
+
+/* check for valid int number (complex, sigh...) */
+#define	IS_VALID_INTNO(n)											\
+	((n) > 0 &&														\
+	 /* autovec and ST-MFP ok anyway */								\
+	 (((n) < TTMFP_SOURCE_BASE) ||									\
+	  /* TT-MFP ok if present */									\
+	  ((n) >= TTMFP_SOURCE_BASE && (n) < SCC_SOURCE_BASE &&			\
+	   ATARIHW_PRESENT(TT_MFP)) ||									\
+	  /* SCC ok if present and number even */						\
+	  ((n) >= SCC_SOURCE_BASE && (n) < VME_SOURCE_BASE &&			\
+	   !((n) & 1) && ATARIHW_PRESENT(SCC)) ||						\
+	  /* greater numbers ok if they are registered VME vectors */		\
+	  ((n) >= VME_SOURCE_BASE && (n) < VME_SOURCE_BASE + VME_MAX_SOURCES && \
+		  free_vme_vec_bitmap & (1 << ((n) - VME_SOURCE_BASE)))))
+
+
+/*
+ * Here start the assembler entry points for interrupts
+ */
+
+#define IRQ_NAME(nr) atari_slow_irq_##nr##_handler(void)
+
+#define	BUILD_SLOW_IRQ(n)						   \
+asmlinkage void IRQ_NAME(n);						   \
+/* Dummy function to allow asm with operands.  */			   \
+void atari_slow_irq_##n##_dummy (void) {				   \
+__asm__ (__ALIGN_STR "\n"						   \
+"atari_slow_irq_" #n "_handler:\t"					   \
+"	addl	%6,%5\n"	/* preempt_count() += HARDIRQ_OFFSET */	   \
+	SAVE_ALL_INT "\n"						   \
+	GET_CURRENT(%%d0) "\n"						   \
+"	andb	#~(1<<(%c3&7)),%a4:w\n"	/* mask this interrupt */	   \
+	/* get old IPL from stack frame */				   \
+"	bfextu	%%sp@(%c2){#5,#3},%%d0\n"				   \
+"	movew	%%sr,%%d1\n"						   \
+"	bfins	%%d0,%%d1{#21,#3}\n"					   \
+"	movew	%%d1,%%sr\n"		/* set IPL = previous value */	   \
+"	addql	#1,%a0\n"						   \
+"	lea	%a1,%%a0\n"						   \
+"	pea	%%sp@\n"		/* push addr of frame */	   \
+"	movel	%%a0@(4),%%sp@-\n"	/* push handler data */		   \
+"	pea	(%c3+8)\n"		/* push int number */		   \
+"	movel	%%a0@,%%a0\n"						   \
+"	jbsr	%%a0@\n"		/* call the handler */		   \
+"	addql	#8,%%sp\n"						   \
+"	addql	#4,%%sp\n"						   \
+"	orw	#0x0600,%%sr\n"						   \
+"	andw	#0xfeff,%%sr\n"		/* set IPL = 6 again */		   \
+"	orb	#(1<<(%c3&7)),%a4:w\n"	/* now unmask the int again */	   \
+"	jbra	ret_from_interrupt\n"					   \
+	 : : "i" (&kstat_cpu(0).irqs[n+8]), "i" (&irq_handler[n+8]),	   \
+	     "n" (PT_OFF_SR), "n" (n),					   \
+	     "i" (n & 8 ? (n & 16 ? &tt_mfp.int_mk_a : &mfp.int_mk_a)	   \
+		        : (n & 16 ? &tt_mfp.int_mk_b : &mfp.int_mk_b)),	   \
+	     "m" (preempt_count()), "di" (HARDIRQ_OFFSET)		   \
+);									   \
+	for (;;);			/* fake noreturn */		   \
+}
+
+BUILD_SLOW_IRQ(0);
+BUILD_SLOW_IRQ(1);
+BUILD_SLOW_IRQ(2);
+BUILD_SLOW_IRQ(3);
+BUILD_SLOW_IRQ(4);
+BUILD_SLOW_IRQ(5);
+BUILD_SLOW_IRQ(6);
+BUILD_SLOW_IRQ(7);
+BUILD_SLOW_IRQ(8);
+BUILD_SLOW_IRQ(9);
+BUILD_SLOW_IRQ(10);
+BUILD_SLOW_IRQ(11);
+BUILD_SLOW_IRQ(12);
+BUILD_SLOW_IRQ(13);
+BUILD_SLOW_IRQ(14);
+BUILD_SLOW_IRQ(15);
+BUILD_SLOW_IRQ(16);
+BUILD_SLOW_IRQ(17);
+BUILD_SLOW_IRQ(18);
+BUILD_SLOW_IRQ(19);
+BUILD_SLOW_IRQ(20);
+BUILD_SLOW_IRQ(21);
+BUILD_SLOW_IRQ(22);
+BUILD_SLOW_IRQ(23);
+BUILD_SLOW_IRQ(24);
+BUILD_SLOW_IRQ(25);
+BUILD_SLOW_IRQ(26);
+BUILD_SLOW_IRQ(27);
+BUILD_SLOW_IRQ(28);
+BUILD_SLOW_IRQ(29);
+BUILD_SLOW_IRQ(30);
+BUILD_SLOW_IRQ(31);
+
+asm_irq_handler slow_handlers[32] = {
+	[0]	= atari_slow_irq_0_handler,
+	[1]	= atari_slow_irq_1_handler,
+	[2]	= atari_slow_irq_2_handler,
+	[3]	= atari_slow_irq_3_handler,
+	[4]	= atari_slow_irq_4_handler,
+	[5]	= atari_slow_irq_5_handler,
+	[6]	= atari_slow_irq_6_handler,
+	[7]	= atari_slow_irq_7_handler,
+	[8]	= atari_slow_irq_8_handler,
+	[9]	= atari_slow_irq_9_handler,
+	[10]	= atari_slow_irq_10_handler,
+	[11]	= atari_slow_irq_11_handler,
+	[12]	= atari_slow_irq_12_handler,
+	[13]	= atari_slow_irq_13_handler,
+	[14]	= atari_slow_irq_14_handler,
+	[15]	= atari_slow_irq_15_handler,
+	[16]	= atari_slow_irq_16_handler,
+	[17]	= atari_slow_irq_17_handler,
+	[18]	= atari_slow_irq_18_handler,
+	[19]	= atari_slow_irq_19_handler,
+	[20]	= atari_slow_irq_20_handler,
+	[21]	= atari_slow_irq_21_handler,
+	[22]	= atari_slow_irq_22_handler,
+	[23]	= atari_slow_irq_23_handler,
+	[24]	= atari_slow_irq_24_handler,
+	[25]	= atari_slow_irq_25_handler,
+	[26]	= atari_slow_irq_26_handler,
+	[27]	= atari_slow_irq_27_handler,
+	[28]	= atari_slow_irq_28_handler,
+	[29]	= atari_slow_irq_29_handler,
+	[30]	= atari_slow_irq_30_handler,
+	[31]	= atari_slow_irq_31_handler
+};
+
+asmlinkage void atari_fast_irq_handler( void );
+asmlinkage void atari_prio_irq_handler( void );
+
+/* Dummy function to allow asm with operands.  */
+void atari_fast_prio_irq_dummy (void) {
+__asm__ (__ALIGN_STR "\n"
+"atari_fast_irq_handler:\n\t"
+	"orw	#0x700,%%sr\n"		/* disable all interrupts */
+"atari_prio_irq_handler:\n\t"
+	"addl	%3,%2\n\t"		/* preempt_count() += HARDIRQ_OFFSET */
+	SAVE_ALL_INT "\n\t"
+	GET_CURRENT(%%d0) "\n\t"
+	/* get vector number from stack frame and convert to source */
+	"bfextu	%%sp@(%c1){#4,#10},%%d0\n\t"
+	"subw	#(0x40-8),%%d0\n\t"
+	"jpl	1f\n\t"
+	"addw	#(0x40-8-0x18),%%d0\n"
+    "1:\tlea	%a0,%%a0\n\t"
+	"addql	#1,%%a0@(%%d0:l:4)\n\t"
+	"lea	irq_handler,%%a0\n\t"
+	"lea	%%a0@(%%d0:l:8),%%a0\n\t"
+	"pea	%%sp@\n\t"		/* push frame address */
+	"movel	%%a0@(4),%%sp@-\n\t"	/* push handler data */
+	"movel	%%d0,%%sp@-\n\t"	/* push int number */
+	"movel	%%a0@,%%a0\n\t"
+	"jsr	%%a0@\n\t"		/* and call the handler */
+	"addql	#8,%%sp\n\t"
+	"addql	#4,%%sp\n\t"
+	"jbra	ret_from_interrupt"
+	 : : "i" (&kstat_cpu(0).irqs), "n" (PT_OFF_FORMATVEC),
+	     "m" (preempt_count()), "di" (HARDIRQ_OFFSET)
+);
+	for (;;);
+}
+
+/* GK:
+ * HBL IRQ handler for Falcon. Nobody needs it :-)
+ * ++andreas: raise ipl to disable further HBLANK interrupts.
+ */
+asmlinkage void falcon_hblhandler(void);
+asm(".text\n"
+__ALIGN_STR "\n\t"
+"falcon_hblhandler:\n\t"
+	"orw	#0x200,%sp@\n\t"	/* set saved ipl to 2 */
+	"rte");
+
+/* Defined in entry.S; only increments 'num_spurious' */
+asmlinkage void bad_interrupt(void);
+
+extern void atari_microwire_cmd( int cmd );
+
+extern int atari_SCC_reset_done;
+
+/*
+ * void atari_init_IRQ (void)
+ *
+ * Parameters:	None
+ *
+ * Returns:	Nothing
+ *
+ * This function should be called during kernel startup to initialize
+ * the atari IRQ handling routines.
+ */
+
+void __init atari_init_IRQ(void)
+{
+	int i;
+
+	/* initialize the vector table */
+	for (i = 0; i < NUM_INT_SOURCES; ++i) {
+		vectors[IRQ_SOURCE_TO_VECTOR(i)] = bad_interrupt;
+	}
+
+	/* Initialize the MFP(s) */
+
+#ifdef ATARI_USE_SOFTWARE_EOI
+	mfp.vec_adr  = 0x48;	/* Software EOI-Mode */
+#else
+	mfp.vec_adr  = 0x40;	/* Automatic EOI-Mode */
+#endif
+	mfp.int_en_a = 0x00;	/* turn off MFP-Ints */
+	mfp.int_en_b = 0x00;
+	mfp.int_mk_a = 0xff;	/* no Masking */
+	mfp.int_mk_b = 0xff;
+
+	if (ATARIHW_PRESENT(TT_MFP)) {
+#ifdef ATARI_USE_SOFTWARE_EOI
+		tt_mfp.vec_adr  = 0x58;		/* Software EOI-Mode */
+#else
+		tt_mfp.vec_adr  = 0x50;		/* Automatic EOI-Mode */
+#endif
+		tt_mfp.int_en_a = 0x00;		/* turn off MFP-Ints */
+		tt_mfp.int_en_b = 0x00;
+		tt_mfp.int_mk_a = 0xff;		/* no Masking */
+		tt_mfp.int_mk_b = 0xff;
+	}
+
+	if (ATARIHW_PRESENT(SCC) && !atari_SCC_reset_done) {
+		scc.cha_a_ctrl = 9;
+		MFPDELAY();
+		scc.cha_a_ctrl = (char) 0xc0; /* hardware reset */
+	}
+
+	if (ATARIHW_PRESENT(SCU)) {
+		/* init the SCU if present */
+		tt_scu.sys_mask = 0x10;		/* enable VBL (for the cursor) and
+									 * disable HSYNC interrupts (who
+									 * needs them?)  MFP and SCC are
+									 * enabled in VME mask
+									 */
+		tt_scu.vme_mask = 0x60;		/* enable MFP and SCC ints */
+	}
+	else {
+		/* If no SCU and no Hades, the HSYNC interrupt needs to be
+		 * disabled this way. (Else _inthandler in kernel/sys_call.S
+		 * gets overruns)
+		 */
+
+		if (!MACH_IS_HADES)
+			vectors[VEC_INT2] = falcon_hblhandler;
+	}
+
+	if (ATARIHW_PRESENT(PCM_8BIT) && ATARIHW_PRESENT(MICROWIRE)) {
+		/* Initialize the LM1992 Sound Controller to enable
+		   the PSG sound.  This is misplaced here, it should
+		   be in an atasound_init(), that doesn't exist yet. */
+		atari_microwire_cmd(MW_LM1992_PSG_HIGH);
+	}
+
+	stdma_init();
+
+	/* Initialize the PSG: all sounds off, both ports output */
+	sound_ym.rd_data_reg_sel = 7;
+	sound_ym.wd_data = 0xff;
+}
+
+
+static irqreturn_t atari_call_irq_list( int irq, void *dev_id, struct pt_regs *fp )
+{
+	irq_node_t *node;
+
+	for (node = (irq_node_t *)dev_id; node; node = node->next)
+		node->handler(irq, node->dev_id, fp);
+	return IRQ_HANDLED;
+}
+
+
+/*
+ * atari_request_irq : add an interrupt service routine for a particular
+ *                     machine specific interrupt source.
+ *                     If the addition was successful, it returns 0.
+ */
+
+int atari_request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *),
+                      unsigned long flags, const char *devname, void *dev_id)
+{
+	int vector;
+	unsigned long oflags = flags;
+
+	/*
+	 * The following is a hack to make some PCI card drivers work,
+	 * which set the SA_SHIRQ flag.
+	 */
+
+	flags &= ~SA_SHIRQ;
+
+	if (flags == SA_INTERRUPT) {
+		printk ("%s: SA_INTERRUPT changed to IRQ_TYPE_SLOW for %s\n",
+			__FUNCTION__, devname);
+		flags = IRQ_TYPE_SLOW;
+	}
+	if (flags < IRQ_TYPE_SLOW || flags > IRQ_TYPE_PRIO) {
+		printk ("%s: Bad irq type 0x%lx <0x%lx> requested from %s\n",
+		        __FUNCTION__, flags, oflags, devname);
+		return -EINVAL;
+	}
+	if (!IS_VALID_INTNO(irq)) {
+		printk ("%s: Unknown irq %d requested from %s\n",
+		        __FUNCTION__, irq, devname);
+		return -ENXIO;
+	}
+	vector = IRQ_SOURCE_TO_VECTOR(irq);
+
+	/*
+	 * Check type/source combination: slow ints are (currently)
+	 * only possible for MFP-interrupts.
+	 */
+	if (flags == IRQ_TYPE_SLOW &&
+		(irq < STMFP_SOURCE_BASE || irq >= SCC_SOURCE_BASE)) {
+		printk ("%s: Slow irq requested for non-MFP source %d from %s\n",
+		        __FUNCTION__, irq, devname);
+		return -EINVAL;
+	}
+
+	if (vectors[vector] == bad_interrupt) {
+		/* int has no handler yet */
+		irq_handler[irq].handler = handler;
+		irq_handler[irq].dev_id  = dev_id;
+		irq_param[irq].flags   = flags;
+		irq_param[irq].devname = devname;
+		vectors[vector] =
+			(flags == IRQ_TYPE_SLOW) ? slow_handlers[irq-STMFP_SOURCE_BASE] :
+			(flags == IRQ_TYPE_FAST) ? atari_fast_irq_handler :
+			                          atari_prio_irq_handler;
+		/* If MFP int, also enable and umask it */
+		atari_turnon_irq(irq);
+		atari_enable_irq(irq);
+
+		return 0;
+	}
+	else if (irq_param[irq].flags == flags) {
+		/* old handler is of same type -> handlers can be chained */
+		irq_node_t *node;
+		unsigned long flags;
+
+		local_irq_save(flags);
+
+		if (irq_handler[irq].handler != atari_call_irq_list) {
+			/* Only one handler yet, make a node for this first one */
+			if (!(node = new_irq_node()))
+				return -ENOMEM;
+			node->handler = irq_handler[irq].handler;
+			node->dev_id  = irq_handler[irq].dev_id;
+			node->devname = irq_param[irq].devname;
+			node->next = NULL;
+
+			irq_handler[irq].handler = atari_call_irq_list;
+			irq_handler[irq].dev_id  = node;
+			irq_param[irq].devname   = "chained";
+		}
+
+		if (!(node = new_irq_node()))
+			return -ENOMEM;
+		node->handler = handler;
+		node->dev_id  = dev_id;
+		node->devname = devname;
+		/* new handlers are put in front of the queue */
+		node->next = irq_handler[irq].dev_id;
+		irq_handler[irq].dev_id = node;
+
+		local_irq_restore(flags);
+		return 0;
+	} else {
+		printk ("%s: Irq %d allocated by other type int (call from %s)\n",
+		        __FUNCTION__, irq, devname);
+		return -EBUSY;
+	}
+}
+
+void atari_free_irq(unsigned int irq, void *dev_id)
+{
+	unsigned long flags;
+	int vector;
+	irq_node_t **list, *node;
+
+	if (!IS_VALID_INTNO(irq)) {
+		printk("%s: Unknown irq %d\n", __FUNCTION__, irq);
+		return;
+	}
+
+	vector = IRQ_SOURCE_TO_VECTOR(irq);
+	if (vectors[vector] == bad_interrupt)
+		goto not_found;
+
+	local_irq_save(flags);
+
+	if (irq_handler[irq].handler != atari_call_irq_list) {
+		/* It's the only handler for the interrupt */
+		if (irq_handler[irq].dev_id != dev_id) {
+			local_irq_restore(flags);
+			goto not_found;
+		}
+		irq_handler[irq].handler = NULL;
+		irq_handler[irq].dev_id  = NULL;
+		irq_param[irq].devname   = NULL;
+		vectors[vector] = bad_interrupt;
+		/* If MFP int, also disable it */
+		atari_disable_irq(irq);
+		atari_turnoff_irq(irq);
+
+		local_irq_restore(flags);
+		return;
+	}
+
+	/* The interrupt is chained, find the irq on the list */
+	for(list = (irq_node_t **)&irq_handler[irq].dev_id; *list; list = &(*list)->next) {
+		if ((*list)->dev_id == dev_id) break;
+	}
+	if (!*list) {
+		local_irq_restore(flags);
+		goto not_found;
+	}
+
+	(*list)->handler = NULL; /* Mark it as free for reallocation */
+	*list = (*list)->next;
+
+	/* If there's now only one handler, unchain the interrupt, i.e. plug in
+	 * the handler directly again and omit atari_call_irq_list */
+	node = (irq_node_t *)irq_handler[irq].dev_id;
+	if (node && !node->next) {
+		irq_handler[irq].handler = node->handler;
+		irq_handler[irq].dev_id  = node->dev_id;
+		irq_param[irq].devname   = node->devname;
+		node->handler = NULL; /* Mark it as free for reallocation */
+	}
+
+	local_irq_restore(flags);
+	return;
+
+not_found:
+	printk("%s: tried to remove invalid irq\n", __FUNCTION__);
+	return;
+}
+
+
+/*
+ * atari_register_vme_int() returns the number of a free interrupt vector for
+ * hardware with a programmable int vector (probably a VME board).
+ */
+
+unsigned long atari_register_vme_int(void)
+{
+	int i;
+
+	for(i = 0; i < 32; i++)
+		if((free_vme_vec_bitmap & (1 << i)) == 0)
+			break;
+
+	if(i == 16)
+		return 0;
+
+	free_vme_vec_bitmap |= 1 << i;
+	return (VME_SOURCE_BASE + i);
+}
+
+
+void atari_unregister_vme_int(unsigned long irq)
+{
+	if(irq >= VME_SOURCE_BASE && irq < VME_SOURCE_BASE + VME_MAX_SOURCES) {
+		irq -= VME_SOURCE_BASE;
+		free_vme_vec_bitmap &= ~(1 << irq);
+	}
+}
+
+
+int show_atari_interrupts(struct seq_file *p, void *v)
+{
+	int i;
+
+	for (i = 0; i < NUM_INT_SOURCES; ++i) {
+		if (vectors[IRQ_SOURCE_TO_VECTOR(i)] == bad_interrupt)
+			continue;
+		if (i < STMFP_SOURCE_BASE)
+			seq_printf(p, "auto %2d: %10u ",
+				       i, kstat_cpu(0).irqs[i]);
+		else
+			seq_printf(p, "vec $%02x: %10u ",
+				       IRQ_SOURCE_TO_VECTOR(i),
+				       kstat_cpu(0).irqs[i]);
+
+		if (irq_handler[i].handler != atari_call_irq_list) {
+			seq_printf(p, "%s\n", irq_param[i].devname);
+		}
+		else {
+			irq_node_t *n;
+			for( n = (irq_node_t *)irq_handler[i].dev_id; n; n = n->next ) {
+				seq_printf(p, "%s\n", n->devname);
+				if (n->next)
+					seq_puts(p, "                    " );
+			}
+		}
+	}
+	if (num_spurious)
+		seq_printf(p, "spurio.: %10u\n", num_spurious);
+
+	return 0;
+}
+
+