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pm.c

/*
 * arch/arm/mach-pnx4008/pm.c
 *
 * Power Management driver for PNX4008
 *
 * Authors: Vitaly Wool, Dmitry Chigirev <source@mvista.com>
 *
 * 2005 (c) MontaVista Software, Inc. This file is licensed under
 * the terms of the GNU General Public License version 2. This program
 * is licensed "as is" without any warranty of any kind, whether express
 * or implied.
 */

#include <linux/pm.h>
#include <linux/rtc.h>
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include <linux/suspend.h>
#include <linux/delay.h>
#include <linux/clk.h>

#include <asm/io.h>
#include <asm/cacheflush.h>
#include <mach/pm.h>
#include <mach/clock.h>

#define SRAM_VA IO_ADDRESS(PNX4008_IRAM_BASE)

static void *saved_sram;

static struct clk *pll4_clk;

static inline void pnx4008_standby(void)
{
      void (*pnx4008_cpu_standby_ptr) (void);

      local_irq_disable();
      local_fiq_disable();

      clk_disable(pll4_clk);

      /*saving portion of SRAM to be used by suspend function. */
      memcpy(saved_sram, (void *)SRAM_VA, pnx4008_cpu_standby_sz);

      /*make sure SRAM copy gets physically written into SDRAM.
         SDRAM will be placed into self-refresh during power down */
      flush_cache_all();

      /*copy suspend function into SRAM */
      memcpy((void *)SRAM_VA, pnx4008_cpu_standby, pnx4008_cpu_standby_sz);

      /*do suspend */
      pnx4008_cpu_standby_ptr = (void *)SRAM_VA;
      pnx4008_cpu_standby_ptr();

      /*restoring portion of SRAM that was used by suspend function */
      memcpy((void *)SRAM_VA, saved_sram, pnx4008_cpu_standby_sz);

      clk_enable(pll4_clk);

      local_fiq_enable();
      local_irq_enable();
}

static inline void pnx4008_suspend(void)
{
      void (*pnx4008_cpu_suspend_ptr) (void);

      local_irq_disable();
      local_fiq_disable();

      clk_disable(pll4_clk);

      __raw_writel(0xffffffff, START_INT_RSR_REG(SE_PIN_BASE_INT));
      __raw_writel(0xffffffff, START_INT_RSR_REG(SE_INT_BASE_INT));

      /*saving portion of SRAM to be used by suspend function. */
      memcpy(saved_sram, (void *)SRAM_VA, pnx4008_cpu_suspend_sz);

      /*make sure SRAM copy gets physically written into SDRAM.
         SDRAM will be placed into self-refresh during power down */
      flush_cache_all();

      /*copy suspend function into SRAM */
      memcpy((void *)SRAM_VA, pnx4008_cpu_suspend, pnx4008_cpu_suspend_sz);

      /*do suspend */
      pnx4008_cpu_suspend_ptr = (void *)SRAM_VA;
      pnx4008_cpu_suspend_ptr();

      /*restoring portion of SRAM that was used by suspend function */
      memcpy((void *)SRAM_VA, saved_sram, pnx4008_cpu_suspend_sz);

      clk_enable(pll4_clk);

      local_fiq_enable();
      local_irq_enable();
}

static int pnx4008_pm_enter(suspend_state_t state)
{
      switch (state) {
      case PM_SUSPEND_STANDBY:
            pnx4008_standby();
            break;
      case PM_SUSPEND_MEM:
            pnx4008_suspend();
            break;
      }
      return 0;
}

static int pnx4008_pm_valid(suspend_state_t state)
{
      return (state == PM_SUSPEND_STANDBY) ||
             (state == PM_SUSPEND_MEM);
}

static struct platform_suspend_ops pnx4008_pm_ops = {
      .enter = pnx4008_pm_enter,
      .valid = pnx4008_pm_valid,
};

static int __init pnx4008_pm_init(void)
{
      u32 sram_size_to_allocate;

      pll4_clk = clk_get(0, "ck_pll4");
      if (IS_ERR(pll4_clk)) {
            printk(KERN_ERR
                   "PM Suspend cannot acquire ARM(PLL4) clock control\n");
            return PTR_ERR(pll4_clk);
      }

      if (pnx4008_cpu_standby_sz > pnx4008_cpu_suspend_sz)
            sram_size_to_allocate = pnx4008_cpu_standby_sz;
      else
            sram_size_to_allocate = pnx4008_cpu_suspend_sz;

      saved_sram = kmalloc(sram_size_to_allocate, GFP_ATOMIC);
      if (!saved_sram) {
            printk(KERN_ERR
                   "PM Suspend: cannot allocate memory to save portion of SRAM\n");
            clk_put(pll4_clk);
            return -ENOMEM;
      }

      suspend_set_ops(&pnx4008_pm_ops);
      return 0;
}

late_initcall(pnx4008_pm_init);

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