// SPDX-License-Identifier: GPL-2.0
#include <linux/init.h>
#include <linux/suspend.h>
#include <linux/io.h>
#include <asm/time.h>
#include <asm/cacheflush.h>
#include <asm/mpc52xx.h>

/* these are defined in mpc52xx_sleep.S, and only used here */
extern void mpc52xx_deep_sleep(void __iomem *sram, void __iomem *sdram_regs,
                struct mpc52xx_cdm __iomem *, struct mpc52xx_intr __iomem*);
extern void mpc52xx_ds_sram(void);
extern const long mpc52xx_ds_sram_size;
extern void mpc52xx_ds_cached(void);
extern const long mpc52xx_ds_cached_size;

static void __iomem *mbar;
static void __iomem *sdram;
static struct mpc52xx_cdm __iomem *cdm;
static struct mpc52xx_intr __iomem *intr;
static struct mpc52xx_gpio_wkup __iomem *gpiow;
static void __iomem *sram;
static int sram_size;

struct mpc52xx_suspend mpc52xx_suspend;

static int mpc52xx_pm_valid(suspend_state_t state)
{
        switch (state) {
        case PM_SUSPEND_STANDBY:
                return 1;
        default:
                return 0;
        }
}

int mpc52xx_set_wakeup_gpio(u8 pin, u8 level)
{
        u16 tmp;

        /* enable gpio */
        out_8(&gpiow->wkup_gpioe, in_8(&gpiow->wkup_gpioe) | (1 << pin));
        /* set as input */
        out_8(&gpiow->wkup_ddr, in_8(&gpiow->wkup_ddr) & ~(1 << pin));
        /* enable deep sleep interrupt */
        out_8(&gpiow->wkup_inten, in_8(&gpiow->wkup_inten) | (1 << pin));
        /* low/high level creates wakeup interrupt */
        tmp = in_be16(&gpiow->wkup_itype);
        tmp &= ~(0x3 << (pin * 2));
        tmp |= (!level + 1) << (pin * 2);
        out_be16(&gpiow->wkup_itype, tmp);
        /* master enable */
        out_8(&gpiow->wkup_maste, 1);

        return 0;
}

int mpc52xx_pm_prepare(void)
{
        struct device_node *np;
        const struct of_device_id immr_ids[] = {
                { .compatible = "fsl,mpc5200-immr", },
                { .compatible = "fsl,mpc5200b-immr", },
                { .type = "soc", .compatible = "mpc5200", }, /* lite5200 */
                { .type = "builtin", .compatible = "mpc5200", }, /* efika */
                {}
        };
        struct resource res;

        /* map the whole register space */
        np = of_find_matching_node(NULL, immr_ids);

        if (of_address_to_resource(np, 0, &res)) {
                pr_err("mpc52xx_pm_prepare(): could not get IMMR address\n");
                of_node_put(np);
                return -ENOSYS;
        }

        mbar = ioremap(res.start, 0xc000); /* we should map whole region including SRAM */

        of_node_put(np);
        if (!mbar) {
                pr_err("mpc52xx_pm_prepare(): could not map registers\n");
                return -ENOSYS;
        }
        /* these offsets are from mpc5200 users manual */
        sdram   = mbar + 0x100;
        cdm     = mbar + 0x200;
        intr    = mbar + 0x500;
        gpiow   = mbar + 0xc00;
        sram    = mbar + 0x8000;        /* Those will be handled by the */
        sram_size = 0x4000;             /* bestcomm driver soon */

        /* call board suspend code, if applicable */
        if (mpc52xx_suspend.board_suspend_prepare)
                mpc52xx_suspend.board_suspend_prepare(mbar);
        else {
                printk(KERN_ALERT "%s: %i don't know how to wake up the board\n",
                                __func__, __LINE__);
                goto out_unmap;
        }

        return 0;

 out_unmap:
        iounmap(mbar);
        return -ENOSYS;
}


char saved_sram[0x4000];

int mpc52xx_pm_enter(suspend_state_t state)
{
        u32 clk_enables;
        u32 msr, hid0;
        u32 intr_main_mask;
        void __iomem * irq_0x500 = (void __iomem *)CONFIG_KERNEL_START + 0x500;
        unsigned long irq_0x500_stop = (unsigned long)irq_0x500 + mpc52xx_ds_cached_size;
        char saved_0x500[0x600-0x500];

        if (WARN_ON(mpc52xx_ds_cached_size > sizeof(saved_0x500)))
                return -ENOMEM;

        /* disable all interrupts in PIC */
        intr_main_mask = in_be32(&intr->main_mask);
        out_be32(&intr->main_mask, intr_main_mask | 0x1ffff);

        /* don't let DEC expire any time soon */
        mtspr(SPRN_DEC, 0x7fffffff);

        /* save SRAM */
        memcpy(saved_sram, sram, sram_size);

        /* copy low level suspend code to sram */
        memcpy(sram, mpc52xx_ds_sram, mpc52xx_ds_sram_size);

        out_8(&cdm->ccs_sleep_enable, 1);
        out_8(&cdm->osc_sleep_enable, 1);
        out_8(&cdm->ccs_qreq_test, 1);

        /* disable all but SDRAM and bestcomm (SRAM) clocks */
        clk_enables = in_be32(&cdm->clk_enables);
        out_be32(&cdm->clk_enables, clk_enables & 0x00088000);

        /* disable power management */
        msr = mfmsr();
        mtmsr(msr & ~MSR_POW);

        /* enable sleep mode, disable others */
        hid0 = mfspr(SPRN_HID0);
        mtspr(SPRN_HID0, (hid0 & ~(HID0_DOZE | HID0_NAP | HID0_DPM)) | HID0_SLEEP);

        /* save original, copy our irq handler, flush from dcache and invalidate icache */
        memcpy(saved_0x500, irq_0x500, mpc52xx_ds_cached_size);
        memcpy(irq_0x500, mpc52xx_ds_cached, mpc52xx_ds_cached_size);
        flush_icache_range((unsigned long)irq_0x500, irq_0x500_stop);

        /* call low-level sleep code */
        mpc52xx_deep_sleep(sram, sdram, cdm, intr);

        /* restore original irq handler */
        memcpy(irq_0x500, saved_0x500, mpc52xx_ds_cached_size);
        flush_icache_range((unsigned long)irq_0x500, irq_0x500_stop);

        /* restore old power mode */
        mtmsr(msr & ~MSR_POW);
        mtspr(SPRN_HID0, hid0);
        mtmsr(msr);

        out_be32(&cdm->clk_enables, clk_enables);
        out_8(&cdm->ccs_sleep_enable, 0);
        out_8(&cdm->osc_sleep_enable, 0);

        /* restore SRAM */
        memcpy(sram, saved_sram, sram_size);

        /* reenable interrupts in PIC */
        out_be32(&intr->main_mask, intr_main_mask);

        return 0;
}

void mpc52xx_pm_finish(void)
{
        /* call board resume code */
        if (mpc52xx_suspend.board_resume_finish)
                mpc52xx_suspend.board_resume_finish(mbar);

        iounmap(mbar);
}

static const struct platform_suspend_ops mpc52xx_pm_ops = {
        .valid          = mpc52xx_pm_valid,
        .prepare        = mpc52xx_pm_prepare,
        .enter          = mpc52xx_pm_enter,
        .finish         = mpc52xx_pm_finish,
};

int __init mpc52xx_pm_init(void)
{
        suspend_set_ops(&mpc52xx_pm_ops);
        return 0;
}