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pm_runtime.c

/*
 * arch/arm/mach-shmobile/pm_runtime.c
 *
 * Runtime PM support code for SuperH Mobile ARM
 *
 *  Copyright (C) 2009-2010 Magnus Damm
 *
 * 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/init.h>
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/pm_runtime.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/sh_clk.h>
#include <linux/bitmap.h>

#ifdef CONFIG_PM_RUNTIME
#define BIT_ONCE 0
#define BIT_ACTIVE 1
#define BIT_CLK_ENABLED 2

struct pm_runtime_data {
      unsigned long flags;
      struct clk *clk;
};

static void __devres_release(struct device *dev, void *res)
{
      struct pm_runtime_data *prd = res;

      dev_dbg(dev, "__devres_release()\n");

      if (test_bit(BIT_CLK_ENABLED, &prd->flags))
            clk_disable(prd->clk);

      if (test_bit(BIT_ACTIVE, &prd->flags))
            clk_put(prd->clk);
}

static struct pm_runtime_data *__to_prd(struct device *dev)
{
      return devres_find(dev, __devres_release, NULL, NULL);
}

static void platform_pm_runtime_init(struct device *dev,
                             struct pm_runtime_data *prd)
{
      if (prd && !test_and_set_bit(BIT_ONCE, &prd->flags)) {
            prd->clk = clk_get(dev, NULL);
            if (!IS_ERR(prd->clk)) {
                  set_bit(BIT_ACTIVE, &prd->flags);
                  dev_info(dev, "clocks managed by runtime pm\n");
            }
      }
}

static void platform_pm_runtime_bug(struct device *dev,
                            struct pm_runtime_data *prd)
{
      if (prd && !test_and_set_bit(BIT_ONCE, &prd->flags))
            dev_err(dev, "runtime pm suspend before resume\n");
}

int platform_pm_runtime_suspend(struct device *dev)
{
      struct pm_runtime_data *prd = __to_prd(dev);

      dev_dbg(dev, "platform_pm_runtime_suspend()\n");

      platform_pm_runtime_bug(dev, prd);

      if (prd && test_bit(BIT_ACTIVE, &prd->flags)) {
            clk_disable(prd->clk);
            clear_bit(BIT_CLK_ENABLED, &prd->flags);
      }

      return 0;
}

int platform_pm_runtime_resume(struct device *dev)
{
      struct pm_runtime_data *prd = __to_prd(dev);

      dev_dbg(dev, "platform_pm_runtime_resume()\n");

      platform_pm_runtime_init(dev, prd);

      if (prd && test_bit(BIT_ACTIVE, &prd->flags)) {
            clk_enable(prd->clk);
            set_bit(BIT_CLK_ENABLED, &prd->flags);
      }

      return 0;
}

int platform_pm_runtime_idle(struct device *dev)
{
      /* suspend synchronously to disable clocks immediately */
      return pm_runtime_suspend(dev);
}

static int platform_bus_notify(struct notifier_block *nb,
                         unsigned long action, void *data)
{
      struct device *dev = data;
      struct pm_runtime_data *prd;

      dev_dbg(dev, "platform_bus_notify() %ld !\n", action);

      if (action == BUS_NOTIFY_BIND_DRIVER) {
            prd = devres_alloc(__devres_release, sizeof(*prd), GFP_KERNEL);
            if (prd)
                  devres_add(dev, prd);
            else
                  dev_err(dev, "unable to alloc memory for runtime pm\n");
      }

      return 0;
}

#else /* CONFIG_PM_RUNTIME */

static int platform_bus_notify(struct notifier_block *nb,
                         unsigned long action, void *data)
{
      struct device *dev = data;
      struct clk *clk;

      dev_dbg(dev, "platform_bus_notify() %ld !\n", action);

      switch (action) {
      case BUS_NOTIFY_BIND_DRIVER:
            clk = clk_get(dev, NULL);
            if (!IS_ERR(clk)) {
                  clk_enable(clk);
                  clk_put(clk);
                  dev_info(dev, "runtime pm disabled, clock forced on\n");
            }
            break;
      case BUS_NOTIFY_UNBOUND_DRIVER:
            clk = clk_get(dev, NULL);
            if (!IS_ERR(clk)) {
                  clk_disable(clk);
                  clk_put(clk);
                  dev_info(dev, "runtime pm disabled, clock forced off\n");
            }
            break;
      }

      return 0;
}

#endif /* CONFIG_PM_RUNTIME */

static struct notifier_block platform_bus_notifier = {
      .notifier_call = platform_bus_notify
};

static int __init sh_pm_runtime_init(void)
{
      bus_register_notifier(&platform_bus_type, &platform_bus_notifier);
      return 0;
}
core_initcall(sh_pm_runtime_init);

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