// SPDX-License-Identifier: GPL-2.0
#include <linux/io.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/export.h>
#include <linux/of.h>
#include <linux/platform_device.h>

static unsigned long acpi_iobase;

#define ACPI_PM_EVT_BLK         (acpi_iobase + 0x00) /* 4 bytes */
#define ACPI_PM_CNT_BLK         (acpi_iobase + 0x04) /* 2 bytes */
#define ACPI_PMA_CNT_BLK        (acpi_iobase + 0x0F) /* 1 byte */
#define ACPI_PM_TMR_BLK         (acpi_iobase + 0x18) /* 4 bytes */
#define ACPI_GPE0_BLK           (acpi_iobase + 0x10) /* 8 bytes */
#define ACPI_END                (acpi_iobase + 0x80)

#define PM_INDEX        0xCD6
#define PM_DATA         0xCD7
#define PM2_INDEX       0xCD0
#define PM2_DATA        0xCD1

static void pmio_write_index(u16 index, u8 reg, u8 value)
{
        outb(reg, index);
        outb(value, index + 1);
}

static u8 pmio_read_index(u16 index, u8 reg)
{
        outb(reg, index);
        return inb(index + 1);
}

static void pm_iowrite(u8 reg, u8 value)
{
        pmio_write_index(PM_INDEX, reg, value);
}

static u8 pm_ioread(u8 reg)
{
        return pmio_read_index(PM_INDEX, reg);
}

static void pm2_iowrite(u8 reg, u8 value)
{
        pmio_write_index(PM2_INDEX, reg, value);
}

static u8 pm2_ioread(u8 reg)
{
        return pmio_read_index(PM2_INDEX, reg);
}

static void acpi_hw_clear_status(void)
{
        u16 value;

        /* PMStatus: Clear WakeStatus/PwrBtnStatus */
        value = inw(ACPI_PM_EVT_BLK);
        value |= (1 << 8 | 1 << 15);
        outw(value, ACPI_PM_EVT_BLK);

        /* GPEStatus: Clear all generated events */
        outl(inl(ACPI_GPE0_BLK), ACPI_GPE0_BLK);
}

static void acpi_registers_setup(void)
{
        u32 value;

        /* PM Status Base */
        pm_iowrite(0x20, ACPI_PM_EVT_BLK & 0xff);
        pm_iowrite(0x21, ACPI_PM_EVT_BLK >> 8);

        /* PM Control Base */
        pm_iowrite(0x22, ACPI_PM_CNT_BLK & 0xff);
        pm_iowrite(0x23, ACPI_PM_CNT_BLK >> 8);

        /* GPM Base */
        pm_iowrite(0x28, ACPI_GPE0_BLK & 0xff);
        pm_iowrite(0x29, ACPI_GPE0_BLK >> 8);

        /* ACPI End */
        pm_iowrite(0x2e, ACPI_END & 0xff);
        pm_iowrite(0x2f, ACPI_END >> 8);

        /* IO Decode: When AcpiDecodeEnable set, South-Bridge uses the contents
         * of the PM registers at index 0x20~0x2B to decode ACPI I/O address. */
        pm_iowrite(0x0e, 1 << 3);

        /* SCI_EN set */
        outw(1, ACPI_PM_CNT_BLK);

        /* Enable to generate SCI */
        pm_iowrite(0x10, pm_ioread(0x10) | 1);

        /* GPM3/GPM9 enable */
        value = inl(ACPI_GPE0_BLK + 4);
        outl(value | (1 << 14) | (1 << 22), ACPI_GPE0_BLK + 4);

        /* Set GPM9 as input */
        pm_iowrite(0x8d, pm_ioread(0x8d) & (~(1 << 1)));

        /* Set GPM9 as non-output */
        pm_iowrite(0x94, pm_ioread(0x94) | (1 << 3));

        /* GPM3 config ACPI trigger SCIOUT */
        pm_iowrite(0x33, pm_ioread(0x33) & (~(3 << 4)));

        /* GPM9 config ACPI trigger SCIOUT */
        pm_iowrite(0x3d, pm_ioread(0x3d) & (~(3 << 2)));

        /* GPM3 config falling edge trigger */
        pm_iowrite(0x37, pm_ioread(0x37) & (~(1 << 6)));

        /* No wait for STPGNT# in ACPI Sx state */
        pm_iowrite(0x7c, pm_ioread(0x7c) | (1 << 6));

        /* Set GPM3 pull-down enable */
        value = pm2_ioread(0xf6);
        value |= ((1 << 7) | (1 << 3));
        pm2_iowrite(0xf6, value);

        /* Set GPM9 pull-down enable */
        value = pm2_ioread(0xf8);
        value |= ((1 << 5) | (1 << 1));
        pm2_iowrite(0xf8, value);
}

static int rs780e_acpi_probe(struct platform_device *pdev)
{
        struct resource *res;

        res = platform_get_resource(pdev, IORESOURCE_IO, 0);
        if (!res)
                return -ENODEV;

        /* SCI interrupt need acpi space, allocate here */
        if (!request_region(res->start, resource_size(res), "acpi")) {
                pr_err("RS780E-ACPI: Failed to request IO Region\n");
                return -EBUSY;
        }

        acpi_iobase = res->start;

        acpi_registers_setup();
        acpi_hw_clear_status();

        return 0;
}

static const struct of_device_id rs780e_acpi_match[] = {
        { .compatible = "loongson,rs780e-acpi" },
        {},
};

static struct platform_driver rs780e_acpi_driver = {
        .probe = rs780e_acpi_probe,
        .driver = {
                .name = "RS780E-ACPI",
                .of_match_table = rs780e_acpi_match,
        },
};
builtin_platform_driver(rs780e_acpi_driver);