// SPDX-License-Identifier: GPL-2.0+
/*
 * rcar-fcp.c  --  R-Car Frame Compression Processor Driver
 *
 * Copyright (C) 2016 Renesas Electronics Corporation
 *
 * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 */

#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>

#include <media/rcar-fcp.h>

#define RCAR_FCP_REG_RST                0x0010
#define RCAR_FCP_REG_RST_SOFTRST        BIT(0)
#define RCAR_FCP_REG_STA                0x0018
#define RCAR_FCP_REG_STA_ACT            BIT(0)

struct rcar_fcp_device {
        struct list_head list;
        struct device *dev;
        void __iomem *base;
};

static LIST_HEAD(fcp_devices);
static DEFINE_MUTEX(fcp_lock);

static inline void rcar_fcp_write(struct rcar_fcp_device *fcp, u32 reg, u32 val)
{
        iowrite32(val, fcp->base + reg);
}

/* -----------------------------------------------------------------------------
 * Public API
 */

/**
 * rcar_fcp_get - Find and acquire a reference to an FCP instance
 * @np: Device node of the FCP instance
 *
 * Search the list of registered FCP instances for the instance corresponding to
 * the given device node.
 *
 * Return a pointer to the FCP instance, or an ERR_PTR if the instance can't be
 * found.
 */
struct rcar_fcp_device *rcar_fcp_get(const struct device_node *np)
{
        struct rcar_fcp_device *fcp;

        mutex_lock(&fcp_lock);

        list_for_each_entry(fcp, &fcp_devices, list) {
                if (fcp->dev->of_node != np)
                        continue;

                get_device(fcp->dev);
                goto done;
        }

        fcp = ERR_PTR(-EPROBE_DEFER);

done:
        mutex_unlock(&fcp_lock);
        return fcp;
}
EXPORT_SYMBOL_GPL(rcar_fcp_get);

/**
 * rcar_fcp_put - Release a reference to an FCP instance
 * @fcp: The FCP instance
 *
 * Release the FCP instance acquired by a call to rcar_fcp_get().
 */
void rcar_fcp_put(struct rcar_fcp_device *fcp)
{
        if (fcp)
                put_device(fcp->dev);
}
EXPORT_SYMBOL_GPL(rcar_fcp_put);

struct device *rcar_fcp_get_device(struct rcar_fcp_device *fcp)
{
        return fcp->dev;
}
EXPORT_SYMBOL_GPL(rcar_fcp_get_device);

/**
 * rcar_fcp_enable - Enable an FCP
 * @fcp: The FCP instance
 *
 * Before any memory access through an FCP is performed by a module, the FCP
 * must be enabled by a call to this function. The enable calls are reference
 * counted, each successful call must be followed by one rcar_fcp_disable()
 * call when no more memory transfer can occur through the FCP.
 *
 * Return 0 on success or a negative error code if an error occurs. The enable
 * reference count isn't increased when this function returns an error.
 */
int rcar_fcp_enable(struct rcar_fcp_device *fcp)
{
        if (!fcp)
                return 0;

        return pm_runtime_resume_and_get(fcp->dev);
}
EXPORT_SYMBOL_GPL(rcar_fcp_enable);

/**
 * rcar_fcp_disable - Disable an FCP
 * @fcp: The FCP instance
 *
 * This function is the counterpart of rcar_fcp_enable(). As enable calls are
 * reference counted a disable call may not disable the FCP synchronously.
 */
void rcar_fcp_disable(struct rcar_fcp_device *fcp)
{
        if (fcp)
                pm_runtime_put(fcp->dev);
}
EXPORT_SYMBOL_GPL(rcar_fcp_disable);

int rcar_fcp_soft_reset(struct rcar_fcp_device *fcp)
{
        u32 value;
        int ret;

        if (!fcp)
                return 0;

        rcar_fcp_write(fcp, RCAR_FCP_REG_RST, RCAR_FCP_REG_RST_SOFTRST);
        ret = readl_poll_timeout(fcp->base + RCAR_FCP_REG_STA,
                                 value, !(value & RCAR_FCP_REG_STA_ACT),
                                 1, 100);
        if (ret)
                dev_err(fcp->dev, "Failed to soft-reset\n");

        return ret;
}
EXPORT_SYMBOL_GPL(rcar_fcp_soft_reset);

/* -----------------------------------------------------------------------------
 * Platform Driver
 */

static int rcar_fcp_probe(struct platform_device *pdev)
{
        struct rcar_fcp_device *fcp;

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

        fcp->dev = &pdev->dev;

        fcp->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(fcp->base))
                return PTR_ERR(fcp->base);

        dma_set_max_seg_size(fcp->dev, UINT_MAX);

        pm_runtime_enable(&pdev->dev);

        mutex_lock(&fcp_lock);
        list_add_tail(&fcp->list, &fcp_devices);
        mutex_unlock(&fcp_lock);

        platform_set_drvdata(pdev, fcp);

        return 0;
}

static void rcar_fcp_remove(struct platform_device *pdev)
{
        struct rcar_fcp_device *fcp = platform_get_drvdata(pdev);

        mutex_lock(&fcp_lock);
        list_del(&fcp->list);
        mutex_unlock(&fcp_lock);

        pm_runtime_disable(&pdev->dev);
}

static const struct of_device_id rcar_fcp_of_match[] = {
        { .compatible = "renesas,fcpf" },
        { .compatible = "renesas,fcpv" },
        { },
};
MODULE_DEVICE_TABLE(of, rcar_fcp_of_match);

static struct platform_driver rcar_fcp_platform_driver = {
        .probe          = rcar_fcp_probe,
        .remove         = rcar_fcp_remove,
        .driver         = {
                .name   = "rcar-fcp",
                .of_match_table = rcar_fcp_of_match,
                .suppress_bind_attrs = true,
        },
};

module_platform_driver(rcar_fcp_platform_driver);

MODULE_ALIAS("rcar-fcp");
MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
MODULE_DESCRIPTION("Renesas FCP Driver");
MODULE_LICENSE("GPL");