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suspend.c

/*
 * MPC83xx suspend support
 *
 * Author: Scott Wood <scottwood@freescale.com>
 *
 * Copyright (c) 2006-2007 Freescale Semiconductor, Inc.
 *
 * 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/pm.h>
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/suspend.h>
#include <linux/fsl_devices.h>
#include <linux/of_platform.h>

#include <asm/reg.h>
#include <asm/io.h>
#include <asm/time.h>
#include <asm/mpc6xx.h>

#include <sysdev/fsl_soc.h>

#define PMCCR1_NEXT_STATE       0x0C /* Next state for power management */
#define PMCCR1_NEXT_STATE_SHIFT 2
#define PMCCR1_CURR_STATE       0x03 /* Current state for power management*/
#define IMMR_RCW_OFFSET         0x900
#define RCW_PCI_HOST            0x80000000

void mpc83xx_enter_deep_sleep(phys_addr_t immrbase);

struct mpc83xx_pmc {
      u32 config;
#define PMCCR_DLPEN 2 /* DDR SDRAM low power enable */
#define PMCCR_SLPEN 1 /* System low power enable */

      u32 event;
      u32 mask;
/* All but PMCI are deep-sleep only */
#define PMCER_GPIO   0x100
#define PMCER_PCI    0x080
#define PMCER_USB    0x040
#define PMCER_ETSEC1 0x020
#define PMCER_ETSEC2 0x010
#define PMCER_TIMER  0x008
#define PMCER_INT1   0x004
#define PMCER_INT2   0x002
#define PMCER_PMCI   0x001
#define PMCER_ALL    0x1FF

      /* deep-sleep only */
      u32 config1;
#define PMCCR1_USE_STATE  0x80000000
#define PMCCR1_PME_EN     0x00000080
#define PMCCR1_ASSERT_PME 0x00000040
#define PMCCR1_POWER_OFF  0x00000020

      /* deep-sleep only */
      u32 config2;
};

struct mpc83xx_rcw {
      u32 rcwlr;
      u32 rcwhr;
};

struct mpc83xx_clock {
      u32 spmr;
      u32 occr;
      u32 sccr;
};

struct pmc_type {
      int has_deep_sleep;
};

static struct of_device *pmc_dev;
static int has_deep_sleep, deep_sleeping;
static int pmc_irq;
static struct mpc83xx_pmc __iomem *pmc_regs;
static struct mpc83xx_clock __iomem *clock_regs;
static int is_pci_agent, wake_from_pci;
static phys_addr_t immrbase;
static int pci_pm_state;
static DECLARE_WAIT_QUEUE_HEAD(agent_wq);

int fsl_deep_sleep(void)
{
      return deep_sleeping;
}

static int mpc83xx_change_state(void)
{
      u32 curr_state;
      u32 reg_cfg1 = in_be32(&pmc_regs->config1);

      if (is_pci_agent) {
            pci_pm_state = (reg_cfg1 & PMCCR1_NEXT_STATE) >>
                           PMCCR1_NEXT_STATE_SHIFT;
            curr_state = reg_cfg1 & PMCCR1_CURR_STATE;

            if (curr_state != pci_pm_state) {
                  reg_cfg1 &= ~PMCCR1_CURR_STATE;
                  reg_cfg1 |= pci_pm_state;
                  out_be32(&pmc_regs->config1, reg_cfg1);

                  wake_up(&agent_wq);
                  return 1;
            }
      }

      return 0;
}

static irqreturn_t pmc_irq_handler(int irq, void *dev_id)
{
      u32 event = in_be32(&pmc_regs->event);
      int ret = IRQ_NONE;

      if (mpc83xx_change_state())
            ret = IRQ_HANDLED;

      if (event) {
            out_be32(&pmc_regs->event, event);
            ret = IRQ_HANDLED;
      }

      return ret;
}

static int mpc83xx_suspend_enter(suspend_state_t state)
{
      int ret = -EAGAIN;

      /* Don't go to sleep if there's a race where pci_pm_state changes
       * between the agent thread checking it and the PM code disabling
       * interrupts.
       */
      if (wake_from_pci) {
            if (pci_pm_state != (deep_sleeping ? 3 : 2))
                  goto out;

            out_be32(&pmc_regs->config1,
                     in_be32(&pmc_regs->config1) | PMCCR1_PME_EN);
      }

      /* Put the system into low-power mode and the RAM
       * into self-refresh mode once the core goes to
       * sleep.
       */

      out_be32(&pmc_regs->config, PMCCR_SLPEN | PMCCR_DLPEN);

      /* If it has deep sleep (i.e. it's an 831x or compatible),
       * disable power to the core upon entering sleep mode.  This will
       * require going through the boot firmware upon a wakeup event.
       */

      if (deep_sleeping) {
            out_be32(&pmc_regs->mask, PMCER_ALL);

            out_be32(&pmc_regs->config1,
                     in_be32(&pmc_regs->config1) | PMCCR1_POWER_OFF);

            enable_kernel_fp();

            mpc83xx_enter_deep_sleep(immrbase);

            out_be32(&pmc_regs->config1,
                     in_be32(&pmc_regs->config1) & ~PMCCR1_POWER_OFF);

            out_be32(&pmc_regs->mask, PMCER_PMCI);
      } else {
            out_be32(&pmc_regs->mask, PMCER_PMCI);

            mpc6xx_enter_standby();
      }

      ret = 0;

out:
      out_be32(&pmc_regs->config1,
               in_be32(&pmc_regs->config1) & ~PMCCR1_PME_EN);

      return ret;
}

static void mpc83xx_suspend_finish(void)
{
      deep_sleeping = 0;
}

static int mpc83xx_suspend_valid(suspend_state_t state)
{
      return state == PM_SUSPEND_STANDBY || state == PM_SUSPEND_MEM;
}

static int mpc83xx_suspend_begin(suspend_state_t state)
{
      switch (state) {
            case PM_SUSPEND_STANDBY:
                  deep_sleeping = 0;
                  return 0;

            case PM_SUSPEND_MEM:
                  if (has_deep_sleep)
                        deep_sleeping = 1;

                  return 0;

            default:
                  return -EINVAL;
      }
}

static int agent_thread_fn(void *data)
{
      while (1) {
            wait_event_interruptible(agent_wq, pci_pm_state >= 2);
            try_to_freeze();

            if (signal_pending(current) || pci_pm_state < 2)
                  continue;

            /* With a preemptible kernel (or SMP), this could race with
             * a userspace-driven suspend request.  It's probably best
             * to avoid mixing the two with such a configuration (or
             * else fix it by adding a mutex to state_store that we can
             * synchronize with).
             */

            wake_from_pci = 1;

            pm_suspend(pci_pm_state == 3 ? PM_SUSPEND_MEM :
                                           PM_SUSPEND_STANDBY);

            wake_from_pci = 0;
      }

      return 0;
}

static void mpc83xx_set_agent(void)
{
      out_be32(&pmc_regs->config1, PMCCR1_USE_STATE);
      out_be32(&pmc_regs->mask, PMCER_PMCI);

      kthread_run(agent_thread_fn, NULL, "PCI power mgt");
}

static int mpc83xx_is_pci_agent(void)
{
      struct mpc83xx_rcw __iomem *rcw_regs;
      int ret;

      rcw_regs = ioremap(get_immrbase() + IMMR_RCW_OFFSET,
                         sizeof(struct mpc83xx_rcw));

      if (!rcw_regs)
            return -ENOMEM;

      ret = !(in_be32(&rcw_regs->rcwhr) & RCW_PCI_HOST);

      iounmap(rcw_regs);
      return ret;
}

static struct platform_suspend_ops mpc83xx_suspend_ops = {
      .valid = mpc83xx_suspend_valid,
      .begin = mpc83xx_suspend_begin,
      .enter = mpc83xx_suspend_enter,
      .finish = mpc83xx_suspend_finish,
};

static int pmc_probe(struct of_device *ofdev,
                     const struct of_device_id *match)
{
      struct device_node *np = ofdev->node;
      struct resource res;
      struct pmc_type *type = match->data;
      int ret = 0;

      if (!of_device_is_available(np))
            return -ENODEV;

      has_deep_sleep = type->has_deep_sleep;
      immrbase = get_immrbase();
      pmc_dev = ofdev;

      is_pci_agent = mpc83xx_is_pci_agent();
      if (is_pci_agent < 0)
            return is_pci_agent;

      ret = of_address_to_resource(np, 0, &res);
      if (ret)
            return -ENODEV;

      pmc_irq = irq_of_parse_and_map(np, 0);
      if (pmc_irq != NO_IRQ) {
            ret = request_irq(pmc_irq, pmc_irq_handler, IRQF_SHARED,
                              "pmc", ofdev);

            if (ret)
                  return -EBUSY;
      }

      pmc_regs = ioremap(res.start, sizeof(struct mpc83xx_pmc));

      if (!pmc_regs) {
            ret = -ENOMEM;
            goto out;
      }

      ret = of_address_to_resource(np, 1, &res);
      if (ret) {
            ret = -ENODEV;
            goto out_pmc;
      }

      clock_regs = ioremap(res.start, sizeof(struct mpc83xx_pmc));

      if (!clock_regs) {
            ret = -ENOMEM;
            goto out_pmc;
      }

      if (is_pci_agent)
            mpc83xx_set_agent();

      suspend_set_ops(&mpc83xx_suspend_ops);
      return 0;

out_pmc:
      iounmap(pmc_regs);
out:
      if (pmc_irq != NO_IRQ)
            free_irq(pmc_irq, ofdev);

      return ret;
}

static int pmc_remove(struct of_device *ofdev)
{
      return -EPERM;
};

static struct pmc_type pmc_types[] = {
      {
            .has_deep_sleep = 1,
      },
      {
            .has_deep_sleep = 0,
      }
};

static struct of_device_id pmc_match[] = {
      {
            .compatible = "fsl,mpc8313-pmc",
            .data = &pmc_types[0],
      },
      {
            .compatible = "fsl,mpc8349-pmc",
            .data = &pmc_types[1],
      },
      {}
};

static struct of_platform_driver pmc_driver = {
      .name = "mpc83xx-pmc",
      .match_table = pmc_match,
      .probe = pmc_probe,
      .remove = pmc_remove
};

static int pmc_init(void)
{
      return of_register_platform_driver(&pmc_driver);
}

module_init(pmc_init);

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