// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2017, National Instruments Corp.
 * Copyright (c) 2017, Xilinx Inc
 *
 * FPGA Bridge Driver for the Xilinx LogiCORE Partial Reconfiguration
 * Decoupler IP Core.
 */

#include <linux/clk.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/fpga/fpga-bridge.h>

#define CTRL_CMD_DECOUPLE       BIT(0)
#define CTRL_CMD_COUPLE         0
#define CTRL_OFFSET             0

struct xlnx_config_data {
        const char *name;
};

struct xlnx_pr_decoupler_data {
        const struct xlnx_config_data *ipconfig;
        void __iomem *io_base;
        struct clk *clk;
};

static inline void xlnx_pr_decoupler_write(struct xlnx_pr_decoupler_data *d,
                                           u32 offset, u32 val)
{
        writel(val, d->io_base + offset);
}

static inline u32 xlnx_pr_decouple_read(const struct xlnx_pr_decoupler_data *d,
                                        u32 offset)
{
        return readl(d->io_base + offset);
}

static int xlnx_pr_decoupler_enable_set(struct fpga_bridge *bridge, bool enable)
{
        int err;
        struct xlnx_pr_decoupler_data *priv = bridge->priv;

        err = clk_enable(priv->clk);
        if (err)
                return err;

        if (enable)
                xlnx_pr_decoupler_write(priv, CTRL_OFFSET, CTRL_CMD_COUPLE);
        else
                xlnx_pr_decoupler_write(priv, CTRL_OFFSET, CTRL_CMD_DECOUPLE);

        clk_disable(priv->clk);

        return 0;
}

static int xlnx_pr_decoupler_enable_show(struct fpga_bridge *bridge)
{
        const struct xlnx_pr_decoupler_data *priv = bridge->priv;
        u32 status;
        int err;

        err = clk_enable(priv->clk);
        if (err)
                return err;

        status = xlnx_pr_decouple_read(priv, CTRL_OFFSET);

        clk_disable(priv->clk);

        return !status;
}

static const struct fpga_bridge_ops xlnx_pr_decoupler_br_ops = {
        .enable_set = xlnx_pr_decoupler_enable_set,
        .enable_show = xlnx_pr_decoupler_enable_show,
};

static const struct xlnx_config_data decoupler_config = {
        .name = "Xilinx PR Decoupler",
};

static const struct xlnx_config_data shutdown_config = {
        .name = "Xilinx DFX AXI Shutdown Manager",
};

static const struct of_device_id xlnx_pr_decoupler_of_match[] = {
        { .compatible = "xlnx,pr-decoupler-1.00", .data = &decoupler_config },
        { .compatible = "xlnx,pr-decoupler", .data = &decoupler_config },
        { .compatible = "xlnx,dfx-axi-shutdown-manager-1.00",
                                        .data = &shutdown_config },
        { .compatible = "xlnx,dfx-axi-shutdown-manager",
                                        .data = &shutdown_config },
        {},
};
MODULE_DEVICE_TABLE(of, xlnx_pr_decoupler_of_match);

static int xlnx_pr_decoupler_probe(struct platform_device *pdev)
{
        struct xlnx_pr_decoupler_data *priv;
        struct fpga_bridge *br;
        int err;

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

        priv->ipconfig = device_get_match_data(&pdev->dev);

        priv->io_base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(priv->io_base))
                return PTR_ERR(priv->io_base);

        priv->clk = devm_clk_get(&pdev->dev, "aclk");
        if (IS_ERR(priv->clk))
                return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk),
                                     "input clock not found\n");

        err = clk_prepare_enable(priv->clk);
        if (err) {
                dev_err(&pdev->dev, "unable to enable clock\n");
                return err;
        }

        clk_disable(priv->clk);

        br = fpga_bridge_register(&pdev->dev, priv->ipconfig->name,
                                  &xlnx_pr_decoupler_br_ops, priv);
        if (IS_ERR(br)) {
                err = PTR_ERR(br);
                dev_err(&pdev->dev, "unable to register %s",
                        priv->ipconfig->name);
                goto err_clk;
        }

        platform_set_drvdata(pdev, br);

        return 0;

err_clk:
        clk_unprepare(priv->clk);

        return err;
}

static void xlnx_pr_decoupler_remove(struct platform_device *pdev)
{
        struct fpga_bridge *bridge = platform_get_drvdata(pdev);
        struct xlnx_pr_decoupler_data *p = bridge->priv;

        fpga_bridge_unregister(bridge);

        clk_unprepare(p->clk);
}

static struct platform_driver xlnx_pr_decoupler_driver = {
        .probe = xlnx_pr_decoupler_probe,
        .remove = xlnx_pr_decoupler_remove,
        .driver = {
                .name = "xlnx_pr_decoupler",
                .of_match_table = xlnx_pr_decoupler_of_match,
        },
};

module_platform_driver(xlnx_pr_decoupler_driver);

MODULE_DESCRIPTION("Xilinx Partial Reconfiguration Decoupler");
MODULE_AUTHOR("Moritz Fischer <mdf@kernel.org>");
MODULE_AUTHOR("Michal Simek <michal.simek@amd.com>");
MODULE_LICENSE("GPL v2");