suspend.c

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/*
 * MPC83xx suspend support
 *
 * Author: Scott Wood <[email protected]>
 *
 * 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 <linux/export.h>

#include <asm/reg.h>
#include <asm/io.h>
#include <asm/time.h>
#include <asm/mpc6xx.h>
#include <asm/switch_to.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_SYSCR_OFFSET       0x100
#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 mpc83xx_syscr {
    __be32 sgprl;
    __be32 sgprh;
    __be32 spridr;
    __be32 :32;
    __be32 spcr;
    __be32 sicrl;
    __be32 sicrh;
};

struct mpc83xx_saved {
    u32 sicrl;
    u32 sicrh;
    u32 sccr;
};

struct pmc_type {
    int has_deep_sleep;
};

static struct platform_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 struct mpc83xx_syscr __iomem *syscr_regs;
static struct mpc83xx_saved saved_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;
}
EXPORT_SYMBOL(fsl_deep_sleep);

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 void mpc83xx_suspend_restore_regs(void)
{
    out_be32(&syscr_regs->sicrl, saved_regs.sicrl);
    out_be32(&syscr_regs->sicrh, saved_regs.sicrh);
    out_be32(&clock_regs->sccr, saved_regs.sccr);
}

static void mpc83xx_suspend_save_regs(void)
{
    saved_regs.sicrl = in_be32(&syscr_regs->sicrl);
    saved_regs.sicrh = in_be32(&syscr_regs->sicrh);
    saved_regs.sccr = in_be32(&clock_regs->sccr);
}

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) {
        mpc83xx_suspend_save_regs();

        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);

        mpc83xx_suspend_restore_regs();
    } 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_end(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 const struct platform_suspend_ops mpc83xx_suspend_ops = {
    .valid = mpc83xx_suspend_valid,
    .begin = mpc83xx_suspend_begin,
    .enter = mpc83xx_suspend_enter,
    .end = mpc83xx_suspend_end,
};

static struct of_device_id pmc_match[];
static int pmc_probe(struct platform_device *ofdev)
{
    const struct of_device_id *match;
    struct device_node *np = ofdev->dev.of_node;
    struct resource res;
    const struct pmc_type *type;
    int ret = 0;

    match = of_match_device(pmc_match, &ofdev->dev);
    if (!match)
        return -EINVAL;

    type = match->data;

    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 (has_deep_sleep) {
        syscr_regs = ioremap(immrbase + IMMR_SYSCR_OFFSET,
                     sizeof(*syscr_regs));
        if (!syscr_regs) {
            ret = -ENOMEM;
            goto out_syscr;
        }
    }

    if (is_pci_agent)
        mpc83xx_set_agent();

    suspend_set_ops(&mpc83xx_suspend_ops);
    return 0;

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

    return ret;
}

static int pmc_remove(struct platform_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 platform_driver pmc_driver = {
    .driver = {
        .name = "mpc83xx-pmc",
        .owner = THIS_MODULE,
        .of_match_table = pmc_match,
    },
    .probe = pmc_probe,
    .remove = pmc_remove
};

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

module_init(pmc_init);