// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2011 Google, Inc.
 */

#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/usb.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/usb/otg.h>
#include <linux/usb/ulpi.h>

#define ULPI_VIEW_WAKEUP        (1 << 31)
#define ULPI_VIEW_RUN           (1 << 30)
#define ULPI_VIEW_WRITE         (1 << 29)
#define ULPI_VIEW_READ          (0 << 29)
#define ULPI_VIEW_ADDR(x)       (((x) & 0xff) << 16)
#define ULPI_VIEW_DATA_READ(x)  (((x) >> 8) & 0xff)
#define ULPI_VIEW_DATA_WRITE(x) ((x) & 0xff)

static int ulpi_viewport_wait(void __iomem *view, u32 mask)
{
        u32 val;

        return readl_poll_timeout_atomic(view, val, !(val & mask), 1, 2000);
}

static int ulpi_viewport_read(struct usb_phy *otg, u32 reg)
{
        int ret;
        void __iomem *view = otg->io_priv;

        writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
        ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
        if (ret)
                return ret;

        writel(ULPI_VIEW_RUN | ULPI_VIEW_READ | ULPI_VIEW_ADDR(reg), view);
        ret = ulpi_viewport_wait(view, ULPI_VIEW_RUN);
        if (ret)
                return ret;

        return ULPI_VIEW_DATA_READ(readl(view));
}

static int ulpi_viewport_write(struct usb_phy *otg, u32 val, u32 reg)
{
        int ret;
        void __iomem *view = otg->io_priv;

        writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
        ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
        if (ret)
                return ret;

        writel(ULPI_VIEW_RUN | ULPI_VIEW_WRITE | ULPI_VIEW_DATA_WRITE(val) |
                                                 ULPI_VIEW_ADDR(reg), view);

        return ulpi_viewport_wait(view, ULPI_VIEW_RUN);
}

struct usb_phy_io_ops ulpi_viewport_access_ops = {
        .read   = ulpi_viewport_read,
        .write  = ulpi_viewport_write,
};
EXPORT_SYMBOL_GPL(ulpi_viewport_access_ops);