// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020, Broadcom */

#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>
#include <linux/iopoll.h>

#include "ehci.h"

#define hcd_to_ehci_priv(h) ((struct brcm_priv *)hcd_to_ehci(h)->priv)

struct brcm_priv {
        struct clk *clk;
};

/*
 * ehci_brcm_wait_for_sof
 * Wait for start of next microframe, then wait extra delay microseconds
 */
static inline void ehci_brcm_wait_for_sof(struct ehci_hcd *ehci, u32 delay)
{
        u32 frame_idx = ehci_readl(ehci, &ehci->regs->frame_index);
        u32 val;
        int res;

        /* Wait for next microframe (every 125 usecs) */
        res = readl_relaxed_poll_timeout_atomic(&ehci->regs->frame_index,
                                                val, val != frame_idx, 1, 130);
        if (res)
                ehci_err(ehci, "Error waiting for SOF\n");
        udelay(delay);
}

/*
 * ehci_brcm_hub_control
 * The EHCI controller has a bug where it can violate the SOF
 * interval between the first two SOF's transmitted after resume
 * if the resume occurs near the end of the microframe. This causees
 * the controller to detect babble on the suspended port and
 * will eventually cause the controller to reset the port.
 * The fix is to Intercept the echi-hcd request to complete RESUME and
 * align it to the start of the next microframe.
 * See SWLINUX-1909 for more details
 */
static int ehci_brcm_hub_control(
        struct usb_hcd  *hcd,
        u16             typeReq,
        u16             wValue,
        u16             wIndex,
        char            *buf,
        u16             wLength)
{
        struct ehci_hcd *ehci = hcd_to_ehci(hcd);
        int             ports = HCS_N_PORTS(ehci->hcs_params);
        u32 __iomem     *status_reg;
        unsigned long flags;
        int retval, irq_disabled = 0;
        u32 temp;

        temp = (wIndex & 0xff) - 1;
        if (temp >= HCS_N_PORTS_MAX)    /* Avoid index-out-of-bounds warning */
                temp = 0;
        status_reg = &ehci->regs->port_status[temp];

        /*
         * RESUME is cleared when GetPortStatus() is called 20ms after start
         * of RESUME
         */
        if ((typeReq == GetPortStatus) &&
            (wIndex && wIndex <= ports) &&
            ehci->reset_done[wIndex-1] &&
            time_after_eq(jiffies, ehci->reset_done[wIndex-1]) &&
            (ehci_readl(ehci, status_reg) & PORT_RESUME)) {

                /*
                 * to make sure we are not interrupted until RESUME bit
                 * is cleared, disable interrupts on current CPU
                 */
                ehci_dbg(ehci, "SOF alignment workaround\n");
                irq_disabled = 1;
                local_irq_save(flags);
                ehci_brcm_wait_for_sof(ehci, 5);
        }
        retval = ehci_hub_control(hcd, typeReq, wValue, wIndex, buf, wLength);
        if (irq_disabled)
                local_irq_restore(flags);
        return retval;
}

static int ehci_brcm_reset(struct usb_hcd *hcd)
{
        struct ehci_hcd *ehci = hcd_to_ehci(hcd);
        int len;

        ehci->big_endian_mmio = 1;

        ehci->caps = (void __iomem *)hcd->regs;
        len = HC_LENGTH(ehci, ehci_readl(ehci, &ehci->caps->hc_capbase));
        ehci->regs = (void __iomem *)(hcd->regs + len);

        /* This fixes the lockup during reboot due to prior interrupts */
        ehci_writel(ehci, CMD_RESET, &ehci->regs->command);
        mdelay(10);

        /*
         * SWLINUX-1705: Avoid OUT packet underflows during high memory
         *   bus usage
         */
        ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[1]);
        ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[3]);

        return ehci_setup(hcd);
}

static struct hc_driver __read_mostly ehci_brcm_hc_driver;

static const struct ehci_driver_overrides brcm_overrides __initconst = {
        .reset = ehci_brcm_reset,
        .extra_priv_size = sizeof(struct brcm_priv),
};

static int ehci_brcm_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct resource *res_mem;
        struct brcm_priv *priv;
        struct usb_hcd *hcd;
        int irq;
        int err;

        err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
        if (err)
                return err;

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        /* Hook the hub control routine to work around a bug */
        ehci_brcm_hc_driver.hub_control = ehci_brcm_hub_control;

        /* initialize hcd */
        hcd = usb_create_hcd(&ehci_brcm_hc_driver, dev, dev_name(dev));
        if (!hcd)
                return -ENOMEM;

        platform_set_drvdata(pdev, hcd);
        priv = hcd_to_ehci_priv(hcd);

        priv->clk = devm_clk_get_optional(dev, NULL);
        if (IS_ERR(priv->clk)) {
                err = PTR_ERR(priv->clk);
                goto err_hcd;
        }

        err = clk_prepare_enable(priv->clk);
        if (err)
                goto err_hcd;

        hcd->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res_mem);
        if (IS_ERR(hcd->regs)) {
                err = PTR_ERR(hcd->regs);
                goto err_clk;
        }
        hcd->rsrc_start = res_mem->start;
        hcd->rsrc_len = resource_size(res_mem);
        err = usb_add_hcd(hcd, irq, IRQF_SHARED);
        if (err)
                goto err_clk;

        device_wakeup_enable(hcd->self.controller);
        device_enable_async_suspend(hcd->self.controller);

        return 0;

err_clk:
        clk_disable_unprepare(priv->clk);
err_hcd:
        usb_put_hcd(hcd);

        return err;
}

static void ehci_brcm_remove(struct platform_device *dev)
{
        struct usb_hcd *hcd = platform_get_drvdata(dev);
        struct brcm_priv *priv = hcd_to_ehci_priv(hcd);

        usb_remove_hcd(hcd);
        clk_disable_unprepare(priv->clk);
        usb_put_hcd(hcd);
}

static int __maybe_unused ehci_brcm_suspend(struct device *dev)
{
        int ret;
        struct usb_hcd *hcd = dev_get_drvdata(dev);
        struct brcm_priv *priv = hcd_to_ehci_priv(hcd);
        bool do_wakeup = device_may_wakeup(dev);

        ret = ehci_suspend(hcd, do_wakeup);
        if (ret)
                return ret;
        clk_disable_unprepare(priv->clk);
        return 0;
}

static int __maybe_unused ehci_brcm_resume(struct device *dev)
{
        struct usb_hcd *hcd = dev_get_drvdata(dev);
        struct ehci_hcd *ehci = hcd_to_ehci(hcd);
        struct brcm_priv *priv = hcd_to_ehci_priv(hcd);
        int err;

        err = clk_prepare_enable(priv->clk);
        if (err)
                return err;
        /*
         * SWLINUX-1705: Avoid OUT packet underflows during high memory
         *   bus usage
         */
        ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[1]);
        ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[3]);

        ehci_resume(hcd, false);

        pm_runtime_disable(dev);
        pm_runtime_set_active(dev);
        pm_runtime_enable(dev);

        return 0;
}

static SIMPLE_DEV_PM_OPS(ehci_brcm_pm_ops, ehci_brcm_suspend,
                ehci_brcm_resume);

static const struct of_device_id brcm_ehci_of_match[] = {
        { .compatible = "brcm,ehci-brcm-v2", },
        { .compatible = "brcm,bcm7445-ehci", },
        {}
};
MODULE_DEVICE_TABLE(of, brcm_ehci_of_match);

static struct platform_driver ehci_brcm_driver = {
        .probe          = ehci_brcm_probe,
        .remove         = ehci_brcm_remove,
        .shutdown       = usb_hcd_platform_shutdown,
        .driver         = {
                .name   = "ehci-brcm",
                .pm     = &ehci_brcm_pm_ops,
                .of_match_table = brcm_ehci_of_match,
        }
};

static int __init ehci_brcm_init(void)
{
        if (usb_disabled())
                return -ENODEV;

        ehci_init_driver(&ehci_brcm_hc_driver, &brcm_overrides);
        return platform_driver_register(&ehci_brcm_driver);
}
module_init(ehci_brcm_init);

static void __exit ehci_brcm_exit(void)
{
        platform_driver_unregister(&ehci_brcm_driver);
}
module_exit(ehci_brcm_exit);

MODULE_ALIAS("platform:ehci-brcm");
MODULE_DESCRIPTION("EHCI Broadcom STB driver");
MODULE_AUTHOR("Al Cooper");
MODULE_LICENSE("GPL");