// SPDX-License-Identifier: GPL-2.0
/*
 * ulpi.c - DesignWare USB3 Controller's ULPI PHY interface
 *
 * Copyright (C) 2015 Intel Corporation
 *
 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
 */

#include <linux/delay.h>
#include <linux/time64.h>
#include <linux/ulpi/regs.h>

#include "core.h"
#include "io.h"

#define DWC3_ULPI_ADDR(a) \
                ((a >= ULPI_EXT_VENDOR_SPECIFIC) ? \
                DWC3_GUSB2PHYACC_ADDR(ULPI_ACCESS_EXTENDED) | \
                DWC3_GUSB2PHYACC_EXTEND_ADDR(a) : DWC3_GUSB2PHYACC_ADDR(a))

#define DWC3_ULPI_BASE_DELAY    DIV_ROUND_UP(NSEC_PER_SEC, 60000000L)

static int dwc3_ulpi_busyloop(struct dwc3 *dwc, u8 addr, bool read)
{
        unsigned long ns = 5L * DWC3_ULPI_BASE_DELAY;
        unsigned int count = 10000;
        u32 reg;

        if (addr >= ULPI_EXT_VENDOR_SPECIFIC)
                ns += DWC3_ULPI_BASE_DELAY;

        if (read)
                ns += DWC3_ULPI_BASE_DELAY;

        reg = dwc3_readl(dwc, DWC3_GUSB2PHYCFG(0));
        if (reg & DWC3_GUSB2PHYCFG_SUSPHY)
                usleep_range(1000, 1200);

        while (count--) {
                ndelay(ns);
                reg = dwc3_readl(dwc, DWC3_GUSB2PHYACC(0));
                if (reg & DWC3_GUSB2PHYACC_DONE)
                        return 0;
                cpu_relax();
        }

        return -ETIMEDOUT;
}

static int dwc3_ulpi_read(struct device *dev, u8 addr)
{
        struct dwc3 *dwc = dev_get_drvdata(dev);
        u32 reg;
        int ret;

        reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
        dwc3_writel(dwc, DWC3_GUSB2PHYACC(0), reg);

        ret = dwc3_ulpi_busyloop(dwc, addr, true);
        if (ret)
                return ret;

        reg = dwc3_readl(dwc, DWC3_GUSB2PHYACC(0));

        return DWC3_GUSB2PHYACC_DATA(reg);
}

static int dwc3_ulpi_write(struct device *dev, u8 addr, u8 val)
{
        struct dwc3 *dwc = dev_get_drvdata(dev);
        u32 reg;

        reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
        reg |= DWC3_GUSB2PHYACC_WRITE | val;
        dwc3_writel(dwc, DWC3_GUSB2PHYACC(0), reg);

        return dwc3_ulpi_busyloop(dwc, addr, false);
}

static const struct ulpi_ops dwc3_ulpi_ops = {
        .read = dwc3_ulpi_read,
        .write = dwc3_ulpi_write,
};

int dwc3_ulpi_init(struct dwc3 *dwc)
{
        /* Register the interface */
        dwc->ulpi = ulpi_register_interface(dwc->dev, &dwc3_ulpi_ops);
        if (IS_ERR(dwc->ulpi)) {
                dev_err(dwc->dev, "failed to register ULPI interface");
                return PTR_ERR(dwc->ulpi);
        }

        return 0;
}

void dwc3_ulpi_exit(struct dwc3 *dwc)
{
        if (dwc->ulpi) {
                ulpi_unregister_interface(dwc->ulpi);
                dwc->ulpi = NULL;
        }
}