linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * FPGA Freeze Bridge Controller

 *

 *  Copyright (C) 2016 Altera Corporation. All rights reserved.

 */

#include <linux/delay.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/of_device.h>

#include <linux/module.h>

#include <linux/fpga/fpga-bridge.h>

​

#define FREEZE_CSR_STATUS_OFFSET        0

#define FREEZE_CSR_CTRL_OFFSET          4

#define FREEZE_CSR_ILLEGAL_REQ_OFFSET       8

#define FREEZE_CSR_REG_VERSION          12

​

#define FREEZE_CSR_SUPPORTED_VERSION        2

#define FREEZE_CSR_OFFICIAL_VERSION     0xad000003

​

#define FREEZE_CSR_STATUS_FREEZE_REQ_DONE   BIT(0)

#define FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE BIT(1)

​

#define FREEZE_CSR_CTRL_FREEZE_REQ      BIT(0)

#define FREEZE_CSR_CTRL_RESET_REQ       BIT(1)

#define FREEZE_CSR_CTRL_UNFREEZE_REQ        BIT(2)

​

#define FREEZE_BRIDGE_NAME          "freeze"

​

struct altera_freeze_br_data {

    struct device *dev;

    void __iomem *base_addr;

    bool enable;

};

​

/*

 * Poll status until status bit is set or we have a timeout.

 */

static int altera_freeze_br_req_ack(struct altera_freeze_br_data *priv,

                    u32 timeout, u32 req_ack)

{

    struct device *dev = priv->dev;

    void __iomem *csr_illegal_req_addr = priv->base_addr +

                         FREEZE_CSR_ILLEGAL_REQ_OFFSET;

    u32 status, illegal, ctrl;

    int ret = -ETIMEDOUT;

​

    do {

        illegal = readl(csr_illegal_req_addr);

        if (illegal) {

            dev_err(dev, "illegal request detected 0x%x", illegal);

​

            writel(1, csr_illegal_req_addr);

​

            illegal = readl(csr_illegal_req_addr);

            if (illegal)

                dev_err(dev, "illegal request not cleared 0x%x",

                    illegal);

​

            ret = -EINVAL;

            break;

        }

​

        status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET);

        dev_dbg(dev, "%s %x %x\n", __func__, status, req_ack);

        status &= req_ack;

        if (status) {

            ctrl = readl(priv->base_addr + FREEZE_CSR_CTRL_OFFSET);

            dev_dbg(dev, "%s request %x acknowledged %x %x\n",

                __func__, req_ack, status, ctrl);

            ret = 0;

            break;

        }

​

        udelay(1);

    } while (timeout--);

​

    if (ret == -ETIMEDOUT)

        dev_err(dev, "%s timeout waiting for 0x%x\n",

            __func__, req_ack);

​

    return ret;

}

​

static int altera_freeze_br_do_freeze(struct altera_freeze_br_data *priv,

                      u32 timeout)

{

    struct device *dev = priv->dev;

    void __iomem *csr_ctrl_addr = priv->base_addr +

                      FREEZE_CSR_CTRL_OFFSET;

    u32 status;