// SPDX-License-Identifier: GPL-2.0-only
/*
 * MPC83xx suspend support
 *
 * Author: Scott Wood <scottwood@freescale.com>
 *
 * Copyright (c) 2006-2007 Freescale Semiconductor, Inc.
 */

#include <linux/pm.h>
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/sched/signal.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/suspend.h>
#include <linux/fsl_devices.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.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 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);

                if (IS_ENABLED(CONFIG_PPC_FPU))
                        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)
{
        set_freezable();

        while (1) {
                wait_event_freezable(agent_wq, pci_pm_state >= 2);

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

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

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

        type = of_device_get_match_data(&ofdev->dev);
        if (!type)
                return -EINVAL;

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

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

        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) {
                ret = request_irq(pmc_irq, pmc_irq_handler, IRQF_SHARED,
                                  "pmc", ofdev);

                if (ret)
                        return -EBUSY;
        }

        pmc_regs = ioremap(res.start, sizeof(*pmc_regs));

        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(*clock_regs));

        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)
                free_irq(pmc_irq, ofdev);

        return ret;
}

static struct platform_driver pmc_driver = {
        .driver = {
                .name = "mpc83xx-pmc",
                .of_match_table = pmc_match,
                .suppress_bind_attrs = true,
        },
        .probe = pmc_probe,
};

builtin_platform_driver(pmc_driver);