/* 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 <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

#define SAVE_UART(va) \
	SAVE_ITEM((va) + S3C2410_ULCON), \
	SAVE_ITEM((va) + S3C2410_UCON), \
	SAVE_ITEM((va) + S3C2410_UFCON), \
	SAVE_ITEM((va) + S3C2410_UMCON), \
	SAVE_ITEM((va) + S3C2410_UBRDIV)

static struct sleep_save uart_save[] = {
	SAVE_UART(S3C_VA_UART0),
	SAVE_UART(S3C_VA_UART1),
#ifndef CONFIG_CPU_S3C2400
	SAVE_UART(S3C_VA_UART2),
#endif
};

static void s3c_pm_save_uart(void)
{
	s3c_pm_do_save(uart_save, ARRAY_SIZE(uart_save));
}

static void s3c_pm_restore_uart(void)
{
	s3c_pm_do_restore(uart_save, ARRAY_SIZE(uart_save));
}
#else
static void s3c_pm_save_uart(void) { }
static void s3c_pm_restore_uart(void) { }
#endif


/* 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)
{
	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;
	}

	/* prepare check area if configured */

	s3c_pm_check_prepare();

	/* 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_uart();
	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();

	/* s3c2410_cpu_save will also act as our return point from when
	 * we resume as it saves its own register state, so use the return
	 * code to differentiate return from save and return from sleep */

	if (s3c2410_cpu_save(regs_save) == 0) {
		flush_cache_all();
		pm_cpu_sleep();
	}

	/* restore the cpu state using the kernel's cpu init code. */

	cpu_init();

	/* restore the system state */

	s3c_pm_restore_core();
	s3c_pm_restore_uart();
	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;
}

static struct platform_suspend_ops s3c_pm_ops = {
	.enter		= s3c_pm_enter,
	.valid		= suspend_valid_only_mem,
};

/* s3c2410_pm_init
 *
 * Attach the power management functions. This should be called
 * from the board specific initialisation if the board supports
 * it.
*/

int __init s3c2410_pm_init(void)
{
	printk("S3C Power Management, Copyright 2004 Simtec Electronics\n");

	suspend_set_ops(&s3c_pm_ops);
	return 0;
}