// SPDX-License-Identifier: GPL-2.0
/*
 * Driver for the Intel P-Unit Mailbox IPC mechanism
 *
 * (C) Copyright 2015 Intel Corporation
 *
 * The heart of the P-Unit is the Foxton microcontroller and its firmware,
 * which provide mailbox interface for power management usage.
 */

#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>

#include <asm/intel_punit_ipc.h>

/* IPC Mailbox registers */
#define OFFSET_DATA_LOW         0x0
#define OFFSET_DATA_HIGH        0x4
/* bit field of interface register */
#define CMD_RUN                 BIT(31)
#define CMD_ERRCODE_MASK        GENMASK(7, 0)
#define CMD_PARA1_SHIFT         8
#define CMD_PARA2_SHIFT         16

#define CMD_TIMEOUT_SECONDS     1

enum {
        BASE_DATA = 0,
        BASE_IFACE,
        BASE_MAX,
};

typedef struct {
        struct device *dev;
        struct mutex lock;
        int irq;
        struct completion cmd_complete;
        /* base of interface and data registers */
        void __iomem *base[RESERVED_IPC][BASE_MAX];
        IPC_TYPE type;
} IPC_DEV;

static IPC_DEV *punit_ipcdev;

static inline u32 ipc_read_status(IPC_DEV *ipcdev, IPC_TYPE type)
{
        return readl(ipcdev->base[type][BASE_IFACE]);
}

static inline void ipc_write_cmd(IPC_DEV *ipcdev, IPC_TYPE type, u32 cmd)
{
        writel(cmd, ipcdev->base[type][BASE_IFACE]);
}

static inline u32 ipc_read_data_low(IPC_DEV *ipcdev, IPC_TYPE type)
{
        return readl(ipcdev->base[type][BASE_DATA] + OFFSET_DATA_LOW);
}

static inline u32 ipc_read_data_high(IPC_DEV *ipcdev, IPC_TYPE type)
{
        return readl(ipcdev->base[type][BASE_DATA] + OFFSET_DATA_HIGH);
}

static inline void ipc_write_data_low(IPC_DEV *ipcdev, IPC_TYPE type, u32 data)
{
        writel(data, ipcdev->base[type][BASE_DATA] + OFFSET_DATA_LOW);
}

static inline void ipc_write_data_high(IPC_DEV *ipcdev, IPC_TYPE type, u32 data)
{
        writel(data, ipcdev->base[type][BASE_DATA] + OFFSET_DATA_HIGH);
}

static const char *ipc_err_string(int error)
{
        if (error == IPC_PUNIT_ERR_SUCCESS)
                return "no error";
        else if (error == IPC_PUNIT_ERR_INVALID_CMD)
                return "invalid command";
        else if (error == IPC_PUNIT_ERR_INVALID_PARAMETER)
                return "invalid parameter";
        else if (error == IPC_PUNIT_ERR_CMD_TIMEOUT)
                return "command timeout";
        else if (error == IPC_PUNIT_ERR_CMD_LOCKED)
                return "command locked";
        else if (error == IPC_PUNIT_ERR_INVALID_VR_ID)
                return "invalid vr id";
        else if (error == IPC_PUNIT_ERR_VR_ERR)
                return "vr error";
        else
                return "unknown error";
}

static int intel_punit_ipc_check_status(IPC_DEV *ipcdev, IPC_TYPE type)
{
        int loops = CMD_TIMEOUT_SECONDS * USEC_PER_SEC;
        int errcode;
        int status;

        if (ipcdev->irq) {
                if (!wait_for_completion_timeout(&ipcdev->cmd_complete,
                                                 CMD_TIMEOUT_SECONDS * HZ)) {
                        dev_err(ipcdev->dev, "IPC timed out\n");
                        return -ETIMEDOUT;
                }
        } else {
                while ((ipc_read_status(ipcdev, type) & CMD_RUN) && --loops)
                        udelay(1);
                if (!loops) {
                        dev_err(ipcdev->dev, "IPC timed out\n");
                        return -ETIMEDOUT;
                }
        }

        status = ipc_read_status(ipcdev, type);
        errcode = status & CMD_ERRCODE_MASK;
        if (errcode) {
                dev_err(ipcdev->dev, "IPC failed: %s, IPC_STS=0x%x\n",
                        ipc_err_string(errcode), status);
                return -EIO;
        }

        return 0;
}

/**
 * intel_punit_ipc_command() - IPC command with data and pointers
 * @cmd:        IPC command code.
 * @para1:      First 8bit parameter, set 0 if not used.
 * @para2:      Second 8bit parameter, set 0 if not used.
 * @in:         Input data, 32bit for BIOS cmd, two 32bit for GTD and ISPD.
 * @out:        Output data.
 *
 * Send a IPC command to P-Unit with data transaction
 *
 * Return:      IPC error code or 0 on success.
 */
int intel_punit_ipc_command(u32 cmd, u32 para1, u32 para2, u32 *in, u32 *out)
{
        IPC_DEV *ipcdev = punit_ipcdev;
        IPC_TYPE type;
        u32 val;
        int ret;

        mutex_lock(&ipcdev->lock);

        reinit_completion(&ipcdev->cmd_complete);
        type = (cmd & IPC_PUNIT_CMD_TYPE_MASK) >> IPC_TYPE_OFFSET;

        if (in) {
                ipc_write_data_low(ipcdev, type, *in);
                if (type == GTDRIVER_IPC || type == ISPDRIVER_IPC)
                        ipc_write_data_high(ipcdev, type, *++in);
        }

        val = cmd & ~IPC_PUNIT_CMD_TYPE_MASK;
        val |= CMD_RUN | para2 << CMD_PARA2_SHIFT | para1 << CMD_PARA1_SHIFT;
        ipc_write_cmd(ipcdev, type, val);

        ret = intel_punit_ipc_check_status(ipcdev, type);
        if (ret)
                goto out;

        if (out) {
                *out = ipc_read_data_low(ipcdev, type);
                if (type == GTDRIVER_IPC || type == ISPDRIVER_IPC)
                        *++out = ipc_read_data_high(ipcdev, type);
        }

out:
        mutex_unlock(&ipcdev->lock);
        return ret;
}
EXPORT_SYMBOL_GPL(intel_punit_ipc_command);

static irqreturn_t intel_punit_ioc(int irq, void *dev_id)
{
        IPC_DEV *ipcdev = dev_id;

        complete(&ipcdev->cmd_complete);
        return IRQ_HANDLED;
}

static int intel_punit_get_bars(struct platform_device *pdev)
{
        void __iomem *addr;

        /*
         * The following resources are required
         * - BIOS_IPC BASE_DATA
         * - BIOS_IPC BASE_IFACE
         */
        addr = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(addr))
                return PTR_ERR(addr);
        punit_ipcdev->base[BIOS_IPC][BASE_DATA] = addr;

        addr = devm_platform_ioremap_resource(pdev, 1);
        if (IS_ERR(addr))
                return PTR_ERR(addr);
        punit_ipcdev->base[BIOS_IPC][BASE_IFACE] = addr;

        /*
         * The following resources are optional
         * - ISPDRIVER_IPC BASE_DATA
         * - ISPDRIVER_IPC BASE_IFACE
         * - GTDRIVER_IPC BASE_DATA
         * - GTDRIVER_IPC BASE_IFACE
         */
        addr = devm_platform_ioremap_resource(pdev, 2);
        if (!IS_ERR(addr))
                punit_ipcdev->base[ISPDRIVER_IPC][BASE_DATA] = addr;

        addr = devm_platform_ioremap_resource(pdev, 3);
        if (!IS_ERR(addr))
                punit_ipcdev->base[ISPDRIVER_IPC][BASE_IFACE] = addr;

        addr = devm_platform_ioremap_resource(pdev, 4);
        if (!IS_ERR(addr))
                punit_ipcdev->base[GTDRIVER_IPC][BASE_DATA] = addr;

        addr = devm_platform_ioremap_resource(pdev, 5);
        if (!IS_ERR(addr))
                punit_ipcdev->base[GTDRIVER_IPC][BASE_IFACE] = addr;

        return 0;
}

static int intel_punit_ipc_probe(struct platform_device *pdev)
{
        int irq, ret;

        punit_ipcdev = devm_kzalloc(&pdev->dev,
                                    sizeof(*punit_ipcdev), GFP_KERNEL);
        if (!punit_ipcdev)
                return -ENOMEM;

        platform_set_drvdata(pdev, punit_ipcdev);

        irq = platform_get_irq_optional(pdev, 0);
        if (irq < 0) {
                dev_warn(&pdev->dev, "Invalid IRQ, using polling mode\n");
        } else {
                ret = devm_request_irq(&pdev->dev, irq, intel_punit_ioc,
                                       IRQF_NO_SUSPEND, "intel_punit_ipc",
                                       punit_ipcdev);
                if (ret) {
                        dev_err(&pdev->dev, "Failed to request irq: %d\n", irq);
                        return ret;
                }
                punit_ipcdev->irq = irq;
        }

        ret = intel_punit_get_bars(pdev);
        if (ret)
                return ret;

        punit_ipcdev->dev = &pdev->dev;
        mutex_init(&punit_ipcdev->lock);
        init_completion(&punit_ipcdev->cmd_complete);

        return 0;
}

static const struct acpi_device_id punit_ipc_acpi_ids[] = {
        { "INT34D4", 0 },
        { }
};
MODULE_DEVICE_TABLE(acpi, punit_ipc_acpi_ids);

static struct platform_driver intel_punit_ipc_driver = {
        .probe = intel_punit_ipc_probe,
        .driver = {
                .name = "intel_punit_ipc",
                .acpi_match_table = punit_ipc_acpi_ids,
        },
};

static int __init intel_punit_ipc_init(void)
{
        return platform_driver_register(&intel_punit_ipc_driver);
}

static void __exit intel_punit_ipc_exit(void)
{
        platform_driver_unregister(&intel_punit_ipc_driver);
}

MODULE_AUTHOR("Zha Qipeng <qipeng.zha@intel.com>");
MODULE_DESCRIPTION("Intel P-Unit IPC driver");
MODULE_LICENSE("GPL v2");

/* Some modules are dependent on this, so init earlier */
fs_initcall(intel_punit_ipc_init);
module_exit(intel_punit_ipc_exit);