Merge branch 'next-s3c-pm' of git://aeryn.fluff.org.uk/bjdooks/linux into devel

4 files changed, 784 insertions, 0 deletions

diff --git a/arch/arm/plat-s3c/Makefile b/arch/arm/plat-s3c/Makefile
index 39195f972d5..8d7815d25a5 100644
--- a/arch/arm/plat-s3c/Makefile
+++ b/arch/arm/plat-s3c/Makefile
@@ -18,6 +18,11 @@ obj-y				+= pwm-clock.o
 obj-y				+= gpio.o
 obj-y				+= gpio-config.o
 
+# PM support
+
+obj-$(CONFIG_PM)		+= pm.o
+obj-$(CONFIG_S3C2410_PM_CHECK)	+= pm-check.o
+
 # devices
 
 obj-$(CONFIG_S3C_DEV_HSMMC)	+= dev-hsmmc.o
diff --git a/arch/arm/plat-s3c/include/plat/pm.h b/arch/arm/plat-s3c/include/plat/pm.h
new file mode 100644
index 00000000000..3779775133a
--- /dev/null
+++ b/arch/arm/plat-s3c/include/plat/pm.h
@@ -0,0 +1,174 @@
+/* linux/include/asm-arm/plat-s3c24xx/pm.h
+ *
+ * Copyright (c) 2004 Simtec Electronics
+ *	http://armlinux.simtec.co.uk/
+ *	Written by Ben Dooks, <ben@simtec.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+/* s3c_pm_init
+ *
+ * called from board at initialisation time to setup the power
+ * management
+*/
+
+#ifdef CONFIG_PM
+
+extern __init int s3c_pm_init(void);
+
+#else
+
+static inline int s3c_pm_init(void)
+{
+	return 0;
+}
+#endif
+
+/* configuration for the IRQ mask over sleep */
+extern unsigned long s3c_irqwake_intmask;
+extern unsigned long s3c_irqwake_eintmask;
+
+/* IRQ masks for IRQs allowed to go to sleep (see irq.c) */
+extern unsigned long s3c_irqwake_intallow;
+extern unsigned long s3c_irqwake_eintallow;
+
+/* per-cpu sleep functions */
+
+extern void (*pm_cpu_prep)(void);
+extern void (*pm_cpu_sleep)(void);
+
+/* Flags for PM Control */
+
+extern unsigned long s3c_pm_flags;
+
+/* from sleep.S */
+
+extern int  s3c_cpu_save(unsigned long *saveblk);
+extern void s3c_cpu_resume(void);
+
+extern void s3c2410_cpu_suspend(void);
+
+extern unsigned long s3c_sleep_save_phys;
+
+/* sleep save info */
+
+/**
+ * struct sleep_save - save information for shared peripherals.
+ * @reg: Pointer to the register to save.
+ * @val: Holder for the value saved from reg.
+ *
+ * This describes a list of registers which is used by the pm core and
+ * other subsystem to save and restore register values over suspend.
+ */
+struct sleep_save {
+	void __iomem	*reg;
+	unsigned long	val;
+};
+
+#define SAVE_ITEM(x) \
+	{ .reg = (x) }
+
+/**
+ * struct pm_uart_save - save block for core UART
+ * @ulcon: Save value for S3C2410_ULCON
+ * @ucon: Save value for S3C2410_UCON
+ * @ufcon: Save value for S3C2410_UFCON
+ * @umcon: Save value for S3C2410_UMCON
+ * @ubrdiv: Save value for S3C2410_UBRDIV
+ *
+ * Save block for UART registers to be held over sleep and restored if they
+ * are needed (say by debug).
+*/
+struct pm_uart_save {
+	u32	ulcon;
+	u32	ucon;
+	u32	ufcon;
+	u32	umcon;
+	u32	ubrdiv;
+};
+
+/* helper functions to save/restore lists of registers. */
+
+extern void s3c_pm_do_save(struct sleep_save *ptr, int count);
+extern void s3c_pm_do_restore(struct sleep_save *ptr, int count);
+extern void s3c_pm_do_restore_core(struct sleep_save *ptr, int count);
+
+#ifdef CONFIG_PM
+extern int s3c_irqext_wake(unsigned int irqno, unsigned int state);
+extern int s3c24xx_irq_suspend(struct sys_device *dev, pm_message_t state);
+extern int s3c24xx_irq_resume(struct sys_device *dev);
+#else
+#define s3c_irqext_wake NULL
+#define s3c24xx_irq_suspend NULL
+#define s3c24xx_irq_resume  NULL
+#endif
+
+/* PM debug functions */
+
+#ifdef CONFIG_S3C2410_PM_DEBUG
+/**
+ * s3c_pm_dbg() - low level debug function for use in suspend/resume.
+ * @msg: The message to print.
+ *
+ * This function is used mainly to debug the resume process before the system
+ * can rely on printk/console output. It uses the low-level debugging output
+ * routine printascii() to do its work.
+ */
+extern void s3c_pm_dbg(const char *msg, ...);
+
+#define S3C_PMDBG(fmt...) s3c_pm_dbg(fmt)
+#else
+#define S3C_PMDBG(fmt...) printk(KERN_DEBUG fmt)
+#endif
+
+/* suspend memory checking */
+
+#ifdef CONFIG_S3C2410_PM_CHECK
+extern void s3c_pm_check_prepare(void);
+extern void s3c_pm_check_restore(void);
+extern void s3c_pm_check_cleanup(void);
+extern void s3c_pm_check_store(void);
+#else
+#define s3c_pm_check_prepare() do { } while(0)
+#define s3c_pm_check_restore() do { } while(0)
+#define s3c_pm_check_cleanup() do { } while(0)
+#define s3c_pm_check_store()   do { } while(0)
+#endif
+
+/**
+ * s3c_pm_configure_extint() - ensure pins are correctly set for IRQ
+ *
+ * Setup all the necessary GPIO pins for waking the system on external
+ * interrupt.
+ */
+extern void s3c_pm_configure_extint(void);
+
+/**
+ * s3c_pm_restore_gpios() - restore the state of the gpios after sleep.
+ *
+ * Restore the state of the GPIO pins after sleep, which may involve ensuring
+ * that we do not glitch the state of the pins from that the bootloader's
+ * resume code has done.
+*/
+extern void s3c_pm_restore_gpios(void);
+
+/**
+ * s3c_pm_save_gpios() - save the state of the GPIOs for restoring after sleep.
+ *
+ * Save the GPIO states for resotration on resume. See s3c_pm_restore_gpios().
+ */
+extern void s3c_pm_save_gpios(void);
+
+/**
+ * s3c_pm_cb_flushcache - callback for assembly code
+ *
+ * Callback to issue flush_cache_all() as this call is
+ * not a directly callable object.
+ */
+extern void s3c_pm_cb_flushcache(void);
+
+extern void s3c_pm_save_core(void);
+extern void s3c_pm_restore_core(void);
diff --git a/arch/arm/plat-s3c/pm-check.c b/arch/arm/plat-s3c/pm-check.c
new file mode 100644
index 00000000000..39f2555564d
--- /dev/null
+++ b/arch/arm/plat-s3c/pm-check.c
@@ -0,0 +1,242 @@
+/* linux/arch/arm/plat-s3c/pm-check.c
+ *  originally in linux/arch/arm/plat-s3c24xx/pm.c
+ *
+ * Copyright (c) 2004,2006,2008 Simtec Electronics
+ *	http://armlinux.simtec.co.uk
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C Power Mangament - suspend/resume memory corruptiuon check.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/kernel.h>
+#include <linux/suspend.h>
+#include <linux/init.h>
+#include <linux/crc32.h>
+#include <linux/ioport.h>
+
+#include <plat/pm.h>
+
+#if CONFIG_S3C2410_PM_CHECK_CHUNKSIZE < 1
+#error CONFIG_S3C2410_PM_CHECK_CHUNKSIZE must be a positive non-zero value
+#endif
+
+/* suspend checking code...
+ *
+ * this next area does a set of crc checks over all the installed
+ * memory, so the system can verify if the resume was ok.
+ *
+ * CONFIG_S3C2410_PM_CHECK_CHUNKSIZE defines the block-size for the CRC,
+ * increasing it will mean that the area corrupted will be less easy to spot,
+ * and reducing the size will cause the CRC save area to grow
+*/
+
+#define CHECK_CHUNKSIZE (CONFIG_S3C2410_PM_CHECK_CHUNKSIZE * 1024)
+
+static u32 crc_size;	/* size needed for the crc block */
+static u32 *crcs;	/* allocated over suspend/resume */
+
+typedef u32 *(run_fn_t)(struct resource *ptr, u32 *arg);
+
+/* s3c_pm_run_res
+ *
+ * go through the given resource list, and look for system ram
+*/
+
+static void s3c_pm_run_res(struct resource *ptr, run_fn_t fn, u32 *arg)
+{
+	while (ptr != NULL) {
+		if (ptr->child != NULL)
+			s3c_pm_run_res(ptr->child, fn, arg);
+
+		if ((ptr->flags & IORESOURCE_MEM) &&
+		    strcmp(ptr->name, "System RAM") == 0) {
+			S3C_PMDBG("Found system RAM at %08lx..%08lx\n",
+				  (unsigned long)ptr->start,
+				  (unsigned long)ptr->end);
+			arg = (fn)(ptr, arg);
+		}
+
+		ptr = ptr->sibling;
+	}
+}
+
+static void s3c_pm_run_sysram(run_fn_t fn, u32 *arg)
+{
+	s3c_pm_run_res(&iomem_resource, fn, arg);
+}
+
+static u32 *s3c_pm_countram(struct resource *res, u32 *val)
+{
+	u32 size = (u32)(res->end - res->start)+1;
+
+	size += CHECK_CHUNKSIZE-1;
+	size /= CHECK_CHUNKSIZE;
+
+	S3C_PMDBG("Area %08lx..%08lx, %d blocks\n",
+		  (unsigned long)res->start, (unsigned long)res->end, size);
+
+	*val += size * sizeof(u32);
+	return val;
+}
+
+/* s3c_pm_prepare_check
+ *
+ * prepare the necessary information for creating the CRCs. This
+ * must be done before the final save, as it will require memory
+ * allocating, and thus touching bits of the kernel we do not
+ * know about.
+*/
+
+void s3c_pm_check_prepare(void)
+{
+	crc_size = 0;
+
+	s3c_pm_run_sysram(s3c_pm_countram, &crc_size);
+
+	S3C_PMDBG("s3c_pm_prepare_check: %u checks needed\n", crc_size);
+
+	crcs = kmalloc(crc_size+4, GFP_KERNEL);
+	if (crcs == NULL)
+		printk(KERN_ERR "Cannot allocated CRC save area\n");
+}
+
+static u32 *s3c_pm_makecheck(struct resource *res, u32 *val)
+{
+	unsigned long addr, left;
+
+	for (addr = res->start; addr < res->end;
+	     addr += CHECK_CHUNKSIZE) {
+		left = res->end - addr;
+
+		if (left > CHECK_CHUNKSIZE)
+			left = CHECK_CHUNKSIZE;
+
+		*val = crc32_le(~0, phys_to_virt(addr), left);
+		val++;
+	}
+
+	return val;
+}
+
+/* s3c_pm_check_store
+ *
+ * compute the CRC values for the memory blocks before the final
+ * sleep.
+*/
+
+void s3c_pm_check_store(void)
+{
+	if (crcs != NULL)
+		s3c_pm_run_sysram(s3c_pm_makecheck, crcs);
+}
+
+/* in_region
+ *
+ * return TRUE if the area defined by ptr..ptr+size contains the
+ * what..what+whatsz
+*/
+
+static inline int in_region(void *ptr, int size, void *what, size_t whatsz)
+{
+	if ((what+whatsz) < ptr)
+		return 0;
+
+	if (what > (ptr+size))
+		return 0;
+
+	return 1;
+}
+
+/**
+ * s3c_pm_runcheck() - helper to check a resource on restore.
+ * @res: The resource to check
+ * @vak: Pointer to list of CRC32 values to check.
+ *
+ * Called from the s3c_pm_check_restore() via s3c_pm_run_sysram(), this
+ * function runs the given memory resource checking it against the stored
+ * CRC to ensure that memory is restored. The function tries to skip as
+ * many of the areas used during the suspend process.
+ */
+static u32 *s3c_pm_runcheck(struct resource *res, u32 *val)
+{
+	void *save_at = phys_to_virt(s3c_sleep_save_phys);
+	unsigned long addr;
+	unsigned long left;
+	void *stkpage;
+	void *ptr;
+	u32 calc;
+
+	stkpage = (void *)((u32)&calc & ~PAGE_MASK);
+
+	for (addr = res->start; addr < res->end;
+	     addr += CHECK_CHUNKSIZE) {
+		left = res->end - addr;
+
+		if (left > CHECK_CHUNKSIZE)
+			left = CHECK_CHUNKSIZE;
+
+		ptr = phys_to_virt(addr);
+
+		if (in_region(ptr, left, stkpage, 4096)) {
+			S3C_PMDBG("skipping %08lx, has stack in\n", addr);
+			goto skip_check;
+		}
+
+		if (in_region(ptr, left, crcs, crc_size)) {
+			S3C_PMDBG("skipping %08lx, has crc block in\n", addr);
+			goto skip_check;
+		}
+
+		if (in_region(ptr, left, save_at, 32*4 )) {
+			S3C_PMDBG("skipping %08lx, has save block in\n", addr);
+			goto skip_check;
+		}
+
+		/* calculate and check the checksum */
+
+		calc = crc32_le(~0, ptr, left);
+		if (calc != *val) {
+			printk(KERN_ERR "Restore CRC error at "
+			       "%08lx (%08x vs %08x)\n", addr, calc, *val);
+
+			S3C_PMDBG("Restore CRC error at %08lx (%08x vs %08x)\n",
+			    addr, calc, *val);
+		}
+
+	skip_check:
+		val++;
+	}
+
+	return val;
+}
+
+/**
+ * s3c_pm_check_restore() - memory check called on resume
+ *
+ * check the CRCs after the restore event and free the memory used
+ * to hold them
+*/
+void s3c_pm_check_restore(void)
+{
+	if (crcs != NULL)
+		s3c_pm_run_sysram(s3c_pm_runcheck, crcs);
+}
+
+/**
+ * s3c_pm_check_cleanup() - free memory resources
+ *
+ * Free the resources that where allocated by the suspend
+ * memory check code. We do this separately from the
+ * s3c_pm_check_restore() function as we cannot call any
+ * functions that might sleep during that resume.
+ */
+void s3c_pm_check_cleanup(void)
+{
+	kfree(crcs);
+	crcs = NULL;
+}
+
diff --git a/arch/arm/plat-s3c/pm.c b/arch/arm/plat-s3c/pm.c
new file mode 100644
index 00000000000..061182ca66e
--- /dev/null
+++ b/arch/arm/plat-s3c/pm.c
@@ -0,0 +1,363 @@
+/* linux/arch/arm/plat-s3c/pm.c
+ *
+ * Copyright 2008 Openmoko, Inc.
+ * Copyright 2004,2006,2008 Simtec Electronics
+ *	Ben Dooks <ben@simtec.co.uk>
+ *	http://armlinux.simtec.co.uk/
+ *
+ * S3C common power management (suspend to ram) support.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/init.h>
+#include <linux/suspend.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/serial_core.h>
+#include <linux/io.h>
+
+#include <asm/cacheflush.h>
+#include <mach/hardware.h>
+
+#include <plat/regs-serial.h>
+#include <mach/regs-clock.h>
+#include <mach/regs-gpio.h>
+#include <mach/regs-mem.h>
+#include <mach/regs-irq.h>
+#include <asm/irq.h>
+
+#include <plat/pm.h>
+#include <plat/pm-core.h>
+
+/* for external use */
+
+unsigned long s3c_pm_flags;
+
+/* Debug code:
+ *
+ * This code supports debug output to the low level UARTs for use on
+ * resume before the console layer is available.
+*/
+
+#ifdef CONFIG_S3C2410_PM_DEBUG
+extern void printascii(const char *);
+
+void s3c_pm_dbg(const char *fmt, ...)
+{
+	va_list va;
+	char buff[256];
+
+	va_start(va, fmt);
+	vsprintf(buff, fmt, va);
+	va_end(va);
+
+	printascii(buff);
+}
+
+static inline void s3c_pm_debug_init(void)
+{
+	/* restart uart clocks so we can use them to output */
+	s3c_pm_debug_init_uart();
+}
+
+#else
+#define s3c_pm_debug_init() do { } while(0)
+
+#endif /* CONFIG_S3C2410_PM_DEBUG */
+
+/* Save the UART configurations if we are configured for debug. */
+
+#ifdef CONFIG_S3C2410_PM_DEBUG
+
+struct pm_uart_save uart_save[CONFIG_SERIAL_SAMSUNG_UARTS];
+
+static void s3c_pm_save_uart(unsigned int uart, struct pm_uart_save *save)
+{
+	void __iomem *regs = S3C_VA_UARTx(uart);
+
+	save->ulcon = __raw_readl(regs + S3C2410_ULCON);
+	save->ucon = __raw_readl(regs + S3C2410_UCON);
+	save->ufcon = __raw_readl(regs + S3C2410_UFCON);
+	save->umcon = __raw_readl(regs + S3C2410_UMCON);
+	save->ubrdiv = __raw_readl(regs + S3C2410_UBRDIV);
+}
+
+static void s3c_pm_save_uarts(void)
+{
+	struct pm_uart_save *save = uart_save;
+	unsigned int uart;
+
+	for (uart = 0; uart < CONFIG_SERIAL_SAMSUNG_UARTS; uart++, save++)
+		s3c_pm_save_uart(uart, save);
+}
+
+static void s3c_pm_restore_uart(unsigned int uart, struct pm_uart_save *save)
+{
+	void __iomem *regs = S3C_VA_UARTx(uart);
+
+	__raw_writel(save->ulcon, regs + S3C2410_ULCON);
+	__raw_writel(save->ucon,  regs + S3C2410_UCON);
+	__raw_writel(save->ufcon, regs + S3C2410_UFCON);
+	__raw_writel(save->umcon, regs + S3C2410_UMCON);
+	__raw_writel(save->ubrdiv, regs + S3C2410_UBRDIV);
+}
+
+static void s3c_pm_restore_uarts(void)
+{
+	struct pm_uart_save *save = uart_save;
+	unsigned int uart;
+
+	for (uart = 0; uart < CONFIG_SERIAL_SAMSUNG_UARTS; uart++, save++)
+		s3c_pm_restore_uart(uart, save);
+}
+#else
+static void s3c_pm_save_uarts(void) { }
+static void s3c_pm_restore_uarts(void) { }
+#endif
+
+/* The IRQ ext-int code goes here, it is too small to currently bother
+ * with its own file. */
+
+unsigned long s3c_irqwake_intmask	= 0xffffffffL;
+unsigned long s3c_irqwake_eintmask	= 0xffffffffL;
+
+int s3c_irqext_wake(unsigned int irqno, unsigned int state)
+{
+	unsigned long bit = 1L << IRQ_EINT_BIT(irqno);
+
+	if (!(s3c_irqwake_eintallow & bit))
+		return -ENOENT;
+
+	printk(KERN_INFO "wake %s for irq %d\n",
+	       state ? "enabled" : "disabled", irqno);
+
+	if (!state)
+		s3c_irqwake_eintmask |= bit;
+	else
+		s3c_irqwake_eintmask &= ~bit;
+
+	return 0;
+}
+
+/* helper functions to save and restore register state */
+
+/**
+ * s3c_pm_do_save() - save a set of registers for restoration on resume.
+ * @ptr: Pointer to an array of registers.
+ * @count: Size of the ptr array.
+ *
+ * Run through the list of registers given, saving their contents in the
+ * array for later restoration when we wakeup.
+ */
+void s3c_pm_do_save(struct sleep_save *ptr, int count)
+{
+	for (; count > 0; count--, ptr++) {
+		ptr->val = __raw_readl(ptr->reg);
+		S3C_PMDBG("saved %p value %08lx\n", ptr->reg, ptr->val);
+	}
+}
+
+/**
+ * s3c_pm_do_restore() - restore register values from the save list.
+ * @ptr: Pointer to an array of registers.
+ * @count: Size of the ptr array.
+ *
+ * Restore the register values saved from s3c_pm_do_save().
+ *
+ * Note, we do not use S3C_PMDBG() in here, as the system may not have
+ * restore the UARTs state yet
+*/
+
+void s3c_pm_do_restore(struct sleep_save *ptr, int count)
+{
+	for (; count > 0; count--, ptr++) {
+		printk(KERN_DEBUG "restore %p (restore %08lx, was %08x)\n",
+		       ptr->reg, ptr->val, __raw_readl(ptr->reg));
+
+		__raw_writel(ptr->val, ptr->reg);
+	}
+}
+
+/**
+ * s3c_pm_do_restore_core() - early restore register values from save list.
+ *
+ * This is similar to s3c_pm_do_restore() except we try and minimise the
+ * side effects of the function in case registers that hardware might need
+ * to work has been restored.
+ *
+ * WARNING: Do not put any debug in here that may effect memory or use
+ * peripherals, as things may be changing!
+*/
+
+void s3c_pm_do_restore_core(struct sleep_save *ptr, int count)
+{
+	for (; count > 0; count--, ptr++)
+		__raw_writel(ptr->val, ptr->reg);
+}
+
+/* s3c2410_pm_show_resume_irqs
+ *
+ * print any IRQs asserted at resume time (ie, we woke from)
+*/
+static void s3c_pm_show_resume_irqs(int start, unsigned long which,
+				    unsigned long mask)
+{
+	int i;
+
+	which &= ~mask;
+
+	for (i = 0; i <= 31; i++) {
+		if (which & (1L<<i)) {
+			S3C_PMDBG("IRQ %d asserted at resume\n", start+i);
+		}
+	}
+}
+
+
+void (*pm_cpu_prep)(void);
+void (*pm_cpu_sleep)(void);
+
+#define any_allowed(mask, allow) (((mask) & (allow)) != (allow))
+
+/* s3c_pm_enter
+ *
+ * central control for sleep/resume process
+*/
+
+static int s3c_pm_enter(suspend_state_t state)
+{
+	static unsigned long regs_save[16];
+
+	/* ensure the debug is initialised (if enabled) */
+
+	s3c_pm_debug_init();
+
+	S3C_PMDBG("%s(%d)\n", __func__, state);
+
+	if (pm_cpu_prep == NULL || pm_cpu_sleep == NULL) {
+		printk(KERN_ERR "%s: error: no cpu sleep function\n", __func__);
+		return -EINVAL;
+	}
+
+	/* check if we have anything to wake-up with... bad things seem
+	 * to happen if you suspend with no wakeup (system will often
+	 * require a full power-cycle)
+	*/
+
+	if (!any_allowed(s3c_irqwake_intmask, s3c_irqwake_intallow) &&
+	    !any_allowed(s3c_irqwake_eintmask, s3c_irqwake_eintallow)) {
+		printk(KERN_ERR "%s: No wake-up sources!\n", __func__);
+		printk(KERN_ERR "%s: Aborting sleep\n", __func__);
+		return -EINVAL;
+	}
+
+	/* store the physical address of the register recovery block */
+
+	s3c_sleep_save_phys = virt_to_phys(regs_save);
+
+	S3C_PMDBG("s3c_sleep_save_phys=0x%08lx\n", s3c_sleep_save_phys);
+
+	/* save all necessary core registers not covered by the drivers */
+
+	s3c_pm_save_gpios();
+	s3c_pm_save_uarts();
+	s3c_pm_save_core();
+
+	/* set the irq configuration for wake */
+
+	s3c_pm_configure_extint();
+
+	S3C_PMDBG("sleep: irq wakeup masks: %08lx,%08lx\n",
+	    s3c_irqwake_intmask, s3c_irqwake_eintmask);
+
+	s3c_pm_arch_prepare_irqs();
+
+	/* call cpu specific preparation */
+
+	pm_cpu_prep();
+
+	/* flush cache back to ram */
+
+	flush_cache_all();
+
+	s3c_pm_check_store();
+
+	/* send the cpu to sleep... */
+
+	s3c_pm_arch_stop_clocks();
+
+	/* s3c_cpu_save will also act as our return point from when
+	 * we resume as it saves its own register state and restores it
+	 * during the resume.  */
+
+	s3c_cpu_save(regs_save);
+
+	/* restore the cpu state using the kernel's cpu init code. */
+
+	cpu_init();
+
+	/* restore the system state */
+
+	s3c_pm_restore_core();
+	s3c_pm_restore_uarts();
+	s3c_pm_restore_gpios();
+
+	s3c_pm_debug_init();
+
+	/* check what irq (if any) restored the system */
+
+	s3c_pm_arch_show_resume_irqs();
+
+	S3C_PMDBG("%s: post sleep, preparing to return\n", __func__);
+
+	s3c_pm_check_restore();
+
+	/* ok, let's return from sleep */
+
+	S3C_PMDBG("S3C PM Resume (post-restore)\n");
+	return 0;
+}
+
+/* callback from assembly code */
+void s3c_pm_cb_flushcache(void)
+{
+	flush_cache_all();
+}
+
+static int s3c_pm_prepare(void)
+{
+	/* prepare check area if configured */
+
+	s3c_pm_check_prepare();
+	return 0;
+}
+
+static void s3c_pm_finish(void)
+{
+	s3c_pm_check_cleanup();
+}
+
+static struct platform_suspend_ops s3c_pm_ops = {
+	.enter		= s3c_pm_enter,
+	.prepare	= s3c_pm_prepare,
+	.finish		= s3c_pm_finish,
+	.valid		= suspend_valid_only_mem,
+};
+
+/* s3c_pm_init
+ *
+ * Attach the power management functions. This should be called
+ * from the board specific initialisation if the board supports
+ * it.
+*/
+
+int __init s3c_pm_init(void)
+{
+	printk("S3C Power Management, Copyright 2004 Simtec Electronics\n");
+
+	suspend_set_ops(&s3c_pm_ops);
+	return 0;
+}