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pm.c

/* linux/arch/arm/plat-s3c/pm.c
 *
 * Copyright 2008 Openmoko, Inc.
 * Copyright 2004-2008 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 <mach/map.h>

#include <plat/regs-serial.h>
#include <mach/regs-clock.h>
#include <mach/regs-irq.h>
#include <asm/irq.h>

#include <plat/pm.h>
#include <mach/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_SAMSUNG_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_SAMSUNG_PM_DEBUG */

/* Save the UART configurations if we are configured for debug. */

unsigned char pm_uart_udivslot;

#ifdef CONFIG_SAMSUNG_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);

      if (pm_uart_udivslot)
            save->udivslot = __raw_readl(regs + S3C2443_DIVSLOT);

      S3C_PMDBG("UART[%d]: ULCON=%04x, UCON=%04x, UFCON=%04x, UBRDIV=%04x\n",
              uart, save->ulcon, save->ucon, save->ufcon, save->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);

      s3c_pm_arch_update_uart(regs, save);

      __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);

      if (pm_uart_udivslot)
            __raw_writel(save->udivslot, regs + S3C2443_DIVSLOT);
}

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(struct irq_data *data, unsigned int state)
{
      unsigned long bit = 1L << IRQ_EINT_BIT(data->irq);

      if (!(s3c_irqwake_eintallow & bit))
            return -ENOENT;

      printk(KERN_INFO "wake %s for irq %d\n",
             state ? "enabled" : "disabled", data->irq);

      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__);

      /* LEDs should now be 1110 */
      s3c_pm_debug_smdkled(1 << 1, 0);

      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 const 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;
}

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