/*
 * EHCI-compliant USB host controller driver for NVIDIA Tegra SoCs
 *
 * Copyright (C) 2010 Google, Inc.
 * Copyright (C) 2009 - 2013 NVIDIA Corporation
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 */

#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>
#include <linux/slab.h>
#include <linux/usb/ehci_def.h>
#include <linux/usb/tegra_usb_phy.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>
#include <linux/usb/otg.h>

#include "ehci.h"

#define PORT_WAKE_BITS (PORT_WKOC_E|PORT_WKDISC_E|PORT_WKCONN_E)

#define TEGRA_USB_DMA_ALIGN 32

#define DRIVER_DESC "Tegra EHCI driver"
#define DRV_NAME "tegra-ehci"

static struct hc_driver __read_mostly tegra_ehci_hc_driver;
static bool usb1_reset_attempted;

struct tegra_ehci_soc_config {
        bool has_hostpc;
};

struct tegra_ehci_hcd {
        struct tegra_usb_phy *phy;
        struct clk *clk;
        struct reset_control *rst;
        int port_resuming;
        bool needs_double_reset;
        enum tegra_usb_phy_port_speed port_speed;
};

/*
 * The 1st USB controller contains some UTMI pad registers that are global for
 * all the controllers on the chip. Those registers are also cleared when
 * reset is asserted to the 1st controller. This means that the 1st controller
 * can only be reset when no other controlled has finished probing. So we'll
 * reset the 1st controller before doing any other setup on any of the
 * controllers, and then never again.
 *
 * Since this is a PHY issue, the Tegra PHY driver should probably be doing
 * the resetting of the USB controllers. But to keep compatibility with old
 * device trees that don't have reset phandles in the PHYs, do it here.
 * Those old DTs will be vulnerable to total USB breakage if the 1st EHCI
 * device isn't the first one to finish probing, so warn them.
 */
static int tegra_reset_usb_controller(struct platform_device *pdev)
{
        struct device_node *phy_np;
        struct usb_hcd *hcd = platform_get_drvdata(pdev);
        struct tegra_ehci_hcd *tegra =
                (struct tegra_ehci_hcd *)hcd_to_ehci(hcd)->priv;
        bool has_utmi_pad_registers = false;

        phy_np = of_parse_phandle(pdev->dev.of_node, "nvidia,phy", 0);
        if (!phy_np)
                return -ENOENT;

        if (of_property_read_bool(phy_np, "nvidia,has-utmi-pad-registers"))
                has_utmi_pad_registers = true;

        if (!usb1_reset_attempted) {
                struct reset_control *usb1_reset;

                if (!has_utmi_pad_registers)
                        usb1_reset = of_reset_control_get(phy_np, "utmi-pads");
                else
                        usb1_reset = tegra->rst;

                if (IS_ERR(usb1_reset)) {
                        dev_warn(&pdev->dev,
                                 "can't get utmi-pads reset from the PHY\n");
                        dev_warn(&pdev->dev,
                                 "continuing, but please update your DT\n");
                } else {
                        reset_control_assert(usb1_reset);
                        udelay(1);
                        reset_control_deassert(usb1_reset);

                        if (!has_utmi_pad_registers)
                                reset_control_put(usb1_reset);
                }

                usb1_reset_attempted = true;
        }

        if (!has_utmi_pad_registers) {
                reset_control_assert(tegra->rst);
                udelay(1);
                reset_control_deassert(tegra->rst);
        }

        of_node_put(phy_np);

        return 0;
}

static int tegra_ehci_internal_port_reset(
        struct ehci_hcd *ehci,
        u32 __iomem     *portsc_reg
)
{
        u32             temp;
        unsigned long   flags;
        int             retval = 0;
        int             i, tries;
        u32             saved_usbintr;

        spin_lock_irqsave(&ehci->lock, flags);
        saved_usbintr = ehci_readl(ehci, &ehci->regs->intr_enable);
        /* disable USB interrupt */
        ehci_writel(ehci, 0, &ehci->regs->intr_enable);
        spin_unlock_irqrestore(&ehci->lock, flags);

        /*
         * Here we have to do Port Reset at most twice for
         * Port Enable bit to be set.
         */
        for (i = 0; i < 2; i++) {
                temp = ehci_readl(ehci, portsc_reg);
                temp |= PORT_RESET;
                ehci_writel(ehci, temp, portsc_reg);
                mdelay(10);
                temp &= ~PORT_RESET;
                ehci_writel(ehci, temp, portsc_reg);
                mdelay(1);
                tries = 100;
                do {
                        mdelay(1);
                        /*
                         * Up to this point, Port Enable bit is
                         * expected to be set after 2 ms waiting.
                         * USB1 usually takes extra 45 ms, for safety,
                         * we take 100 ms as timeout.
                         */
                        temp = ehci_readl(ehci, portsc_reg);
                } while (!(temp & PORT_PE) && tries--);
                if (temp & PORT_PE)
                        break;
        }
        if (i == 2)
                retval = -ETIMEDOUT;

        /*
         * Clear Connect Status Change bit if it's set.
         * We can't clear PORT_PEC. It will also cause PORT_PE to be cleared.
         */
        if (temp & PORT_CSC)
                ehci_writel(ehci, PORT_CSC, portsc_reg);

        /*
         * Write to clear any interrupt status bits that might be set
         * during port reset.
         */
        temp = ehci_readl(ehci, &ehci->regs->status);
        ehci_writel(ehci, temp, &ehci->regs->status);

        /* restore original interrupt enable bits */
        ehci_writel(ehci, saved_usbintr, &ehci->regs->intr_enable);
        return retval;
}

static int tegra_ehci_hub_control(
        struct usb_hcd  *hcd,
        u16             typeReq,
        u16             wValue,
        u16             wIndex,
        char            *buf,
        u16             wLength
)
{
        struct ehci_hcd *ehci = hcd_to_ehci(hcd);
        struct tegra_ehci_hcd *tegra = (struct tegra_ehci_hcd *)ehci->priv;
        u32 __iomem     *status_reg;
        u32             temp;
        unsigned long   flags;
        int             retval = 0;

        status_reg = &ehci->regs->port_status[(wIndex & 0xff) - 1];

        spin_lock_irqsave(&ehci->lock, flags);

        if (typeReq == GetPortStatus) {
                temp = ehci_readl(ehci, status_reg);
                if (tegra->port_resuming && !(temp & PORT_SUSPEND)) {
                        /* Resume completed, re-enable disconnect detection */
                        tegra->port_resuming = 0;
                        tegra_usb_phy_postresume(hcd->usb_phy);
                }
        }

        else if (typeReq == SetPortFeature && wValue == USB_PORT_FEAT_SUSPEND) {
                temp = ehci_readl(ehci, status_reg);
                if ((temp & PORT_PE) == 0 || (temp & PORT_RESET) != 0) {
                        retval = -EPIPE;
                        goto done;
                }

                temp &= ~(PORT_RWC_BITS | PORT_WKCONN_E);
                temp |= PORT_WKDISC_E | PORT_WKOC_E;
                ehci_writel(ehci, temp | PORT_SUSPEND, status_reg);

                /*
                 * If a transaction is in progress, there may be a delay in
                 * suspending the port. Poll until the port is suspended.
                 */
                if (ehci_handshake(ehci, status_reg, PORT_SUSPEND,
                                                PORT_SUSPEND, 5000))
                        pr_err("%s: timeout waiting for SUSPEND\n", __func__);

                set_bit((wIndex & 0xff) - 1, &ehci->suspended_ports);
                goto done;
        }

        /* For USB1 port we need to issue Port Reset twice internally */
        if (tegra->needs_double_reset &&
           (typeReq == SetPortFeature && wValue == USB_PORT_FEAT_RESET)) {
                spin_unlock_irqrestore(&ehci->lock, flags);
                return tegra_ehci_internal_port_reset(ehci, status_reg);
        }

        /*
         * Tegra host controller will time the resume operation to clear the bit
         * when the port control state switches to HS or FS Idle. This behavior
         * is different from EHCI where the host controller driver is required
         * to set this bit to a zero after the resume duration is timed in the
         * driver.
         */
        else if (typeReq == ClearPortFeature &&
                                        wValue == USB_PORT_FEAT_SUSPEND) {
                temp = ehci_readl(ehci, status_reg);
                if ((temp & PORT_RESET) || !(temp & PORT_PE)) {
                        retval = -EPIPE;
                        goto done;
                }

                if (!(temp & PORT_SUSPEND))
                        goto done;

                /* Disable disconnect detection during port resume */
                tegra_usb_phy_preresume(hcd->usb_phy);

                ehci->reset_done[wIndex-1] = jiffies + msecs_to_jiffies(25);

                temp &= ~(PORT_RWC_BITS | PORT_WAKE_BITS);
                /* start resume signalling */
                ehci_writel(ehci, temp | PORT_RESUME, status_reg);
                set_bit(wIndex-1, &ehci->resuming_ports);

                spin_unlock_irqrestore(&ehci->lock, flags);
                msleep(20);
                spin_lock_irqsave(&ehci->lock, flags);

                /* Poll until the controller clears RESUME and SUSPEND */
                if (ehci_handshake(ehci, status_reg, PORT_RESUME, 0, 2000))
                        pr_err("%s: timeout waiting for RESUME\n", __func__);
                if (ehci_handshake(ehci, status_reg, PORT_SUSPEND, 0, 2000))
                        pr_err("%s: timeout waiting for SUSPEND\n", __func__);

                ehci->reset_done[wIndex-1] = 0;
                clear_bit(wIndex-1, &ehci->resuming_ports);

                tegra->port_resuming = 1;
                goto done;
        }

        spin_unlock_irqrestore(&ehci->lock, flags);

        /* Handle the hub control events here */
        return ehci_hub_control(hcd, typeReq, wValue, wIndex, buf, wLength);

done:
        spin_unlock_irqrestore(&ehci->lock, flags);
        return retval;
}

struct dma_aligned_buffer {
        void *kmalloc_ptr;
        void *old_xfer_buffer;
        u8 data[0];
};

static void free_dma_aligned_buffer(struct urb *urb)
{
        struct dma_aligned_buffer *temp;
        size_t length;

        if (!(urb->transfer_flags & URB_ALIGNED_TEMP_BUFFER))
                return;

        temp = container_of(urb->transfer_buffer,
                struct dma_aligned_buffer, data);

        if (usb_urb_dir_in(urb)) {
                if (usb_pipeisoc(urb->pipe))
                        length = urb->transfer_buffer_length;
                else
                        length = urb->actual_length;

                memcpy(temp->old_xfer_buffer, temp->data, length);
        }
        urb->transfer_buffer = temp->old_xfer_buffer;
        kfree(temp->kmalloc_ptr);

        urb->transfer_flags &= ~URB_ALIGNED_TEMP_BUFFER;
}

static int alloc_dma_aligned_buffer(struct urb *urb, gfp_t mem_flags)
{
        struct dma_aligned_buffer *temp, *kmalloc_ptr;
        size_t kmalloc_size;

        if (urb->num_sgs || urb->sg ||
            urb->transfer_buffer_length == 0 ||
            !((uintptr_t)urb->transfer_buffer & (TEGRA_USB_DMA_ALIGN - 1)))
                return 0;

        /* Allocate a buffer with enough padding for alignment */
        kmalloc_size = urb->transfer_buffer_length +
                sizeof(struct dma_aligned_buffer) + TEGRA_USB_DMA_ALIGN - 1;

        kmalloc_ptr = kmalloc(kmalloc_size, mem_flags);
        if (!kmalloc_ptr)
                return -ENOMEM;

        /* Position our struct dma_aligned_buffer such that data is aligned */
        temp = PTR_ALIGN(kmalloc_ptr + 1, TEGRA_USB_DMA_ALIGN) - 1;
        temp->kmalloc_ptr = kmalloc_ptr;
        temp->old_xfer_buffer = urb->transfer_buffer;
        if (usb_urb_dir_out(urb))
                memcpy(temp->data, urb->transfer_buffer,
                       urb->transfer_buffer_length);
        urb->transfer_buffer = temp->data;

        urb->transfer_flags |= URB_ALIGNED_TEMP_BUFFER;

        return 0;
}

static int tegra_ehci_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
                                      gfp_t mem_flags)
{
        int ret;

        ret = alloc_dma_aligned_buffer(urb, mem_flags);
        if (ret)
                return ret;

        ret = usb_hcd_map_urb_for_dma(hcd, urb, mem_flags);
        if (ret)
                free_dma_aligned_buffer(urb);

        return ret;
}

static void tegra_ehci_unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
{
        usb_hcd_unmap_urb_for_dma(hcd, urb);
        free_dma_aligned_buffer(urb);
}

static const struct tegra_ehci_soc_config tegra30_soc_config = {
        .has_hostpc = true,
};

static const struct tegra_ehci_soc_config tegra20_soc_config = {
        .has_hostpc = false,
};

static const struct of_device_id tegra_ehci_of_match[] = {
        { .compatible = "nvidia,tegra30-ehci", .data = &tegra30_soc_config },
        { .compatible = "nvidia,tegra20-ehci", .data = &tegra20_soc_config },
        { },
};

static int tegra_ehci_probe(struct platform_device *pdev)
{
        const struct of_device_id *match;
        const struct tegra_ehci_soc_config *soc_config;
        struct resource *res;
        struct usb_hcd *hcd;
        struct ehci_hcd *ehci;
        struct tegra_ehci_hcd *tegra;
        int err = 0;
        int irq;
        struct usb_phy *u_phy;

        match = of_match_device(tegra_ehci_of_match, &pdev->dev);
        if (!match) {
                dev_err(&pdev->dev, "Error: No device match found\n");
                return -ENODEV;
        }
        soc_config = match->data;

        /* Right now device-tree probed devices don't get dma_mask set.
         * Since shared usb code relies on it, set it here for now.
         * Once we have dma capability bindings this can go away.
         */
        err = dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
        if (err)
                return err;

        hcd = usb_create_hcd(&tegra_ehci_hc_driver, &pdev->dev,
                                        dev_name(&pdev->dev));
        if (!hcd) {
                dev_err(&pdev->dev, "Unable to create HCD\n");
                return -ENOMEM;
        }
        platform_set_drvdata(pdev, hcd);
        ehci = hcd_to_ehci(hcd);
        tegra = (struct tegra_ehci_hcd *)ehci->priv;

        hcd->has_tt = 1;

        tegra->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(tegra->clk)) {
                dev_err(&pdev->dev, "Can't get ehci clock\n");
                err = PTR_ERR(tegra->clk);
                goto cleanup_hcd_create;
        }

        tegra->rst = devm_reset_control_get(&pdev->dev, "usb");
        if (IS_ERR(tegra->rst)) {
                dev_err(&pdev->dev, "Can't get ehci reset\n");
                err = PTR_ERR(tegra->rst);
                goto cleanup_hcd_create;
        }

        err = clk_prepare_enable(tegra->clk);
        if (err)
                goto cleanup_hcd_create;

        err = tegra_reset_usb_controller(pdev);
        if (err)
                goto cleanup_clk_en;

        u_phy = devm_usb_get_phy_by_phandle(&pdev->dev, "nvidia,phy", 0);
        if (IS_ERR(u_phy)) {
                err = -EPROBE_DEFER;
                goto cleanup_clk_en;
        }
        hcd->usb_phy = u_phy;

        tegra->needs_double_reset = of_property_read_bool(pdev->dev.of_node,
                "nvidia,needs-double-reset");

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        hcd->regs = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(hcd->regs)) {
                err = PTR_ERR(hcd->regs);
                goto cleanup_clk_en;
        }
        hcd->rsrc_start = res->start;
        hcd->rsrc_len = resource_size(res);

        ehci->caps = hcd->regs + 0x100;
        ehci->has_hostpc = soc_config->has_hostpc;

        err = usb_phy_init(hcd->usb_phy);
        if (err) {
                dev_err(&pdev->dev, "Failed to initialize phy\n");
                goto cleanup_clk_en;
        }

        u_phy->otg = devm_kzalloc(&pdev->dev, sizeof(struct usb_otg),
                             GFP_KERNEL);
        if (!u_phy->otg) {
                err = -ENOMEM;
                goto cleanup_phy;
        }
        u_phy->otg->host = hcd_to_bus(hcd);

        err = usb_phy_set_suspend(hcd->usb_phy, 0);
        if (err) {
                dev_err(&pdev->dev, "Failed to power on the phy\n");
                goto cleanup_phy;
        }

        irq = platform_get_irq(pdev, 0);
        if (!irq) {
                dev_err(&pdev->dev, "Failed to get IRQ\n");
                err = -ENODEV;
                goto cleanup_phy;
        }

        otg_set_host(u_phy->otg, &hcd->self);

        err = usb_add_hcd(hcd, irq, IRQF_SHARED);
        if (err) {
                dev_err(&pdev->dev, "Failed to add USB HCD\n");
                goto cleanup_otg_set_host;
        }
        device_wakeup_enable(hcd->self.controller);

        return err;

cleanup_otg_set_host:
        otg_set_host(u_phy->otg, NULL);
cleanup_phy:
        usb_phy_shutdown(hcd->usb_phy);
cleanup_clk_en:
        clk_disable_unprepare(tegra->clk);
cleanup_hcd_create:
        usb_put_hcd(hcd);
        return err;
}

static int tegra_ehci_remove(struct platform_device *pdev)
{
        struct usb_hcd *hcd = platform_get_drvdata(pdev);
        struct tegra_ehci_hcd *tegra =
                (struct tegra_ehci_hcd *)hcd_to_ehci(hcd)->priv;

        otg_set_host(hcd->usb_phy->otg, NULL);

        usb_phy_shutdown(hcd->usb_phy);
        usb_remove_hcd(hcd);

        clk_disable_unprepare(tegra->clk);

        usb_put_hcd(hcd);

        return 0;
}

static void tegra_ehci_hcd_shutdown(struct platform_device *pdev)
{
        struct usb_hcd *hcd = platform_get_drvdata(pdev);

        if (hcd->driver->shutdown)
                hcd->driver->shutdown(hcd);
}

static struct platform_driver tegra_ehci_driver = {
        .probe          = tegra_ehci_probe,
        .remove         = tegra_ehci_remove,
        .shutdown       = tegra_ehci_hcd_shutdown,
        .driver         = {
                .name   = DRV_NAME,
                .of_match_table = tegra_ehci_of_match,
        }
};

static int tegra_ehci_reset(struct usb_hcd *hcd)
{
        struct ehci_hcd *ehci = hcd_to_ehci(hcd);
        int retval;
        int txfifothresh;

        retval = ehci_setup(hcd);
        if (retval)
                return retval;

        /*
         * We should really pull this value out of tegra_ehci_soc_config, but
         * to avoid needing access to it, make use of the fact that Tegra20 is
         * the only one so far that needs a value of 10, and Tegra20 is the
         * only one which doesn't set has_hostpc.
         */
        txfifothresh = ehci->has_hostpc ? 0x10 : 10;
        ehci_writel(ehci, txfifothresh << 16, &ehci->regs->txfill_tuning);

        return 0;
}

static const struct ehci_driver_overrides tegra_overrides __initconst = {
        .extra_priv_size        = sizeof(struct tegra_ehci_hcd),
        .reset                  = tegra_ehci_reset,
};

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

        pr_info(DRV_NAME ": " DRIVER_DESC "\n");

        ehci_init_driver(&tegra_ehci_hc_driver, &tegra_overrides);

        /*
         * The Tegra HW has some unusual quirks, which require Tegra-specific
         * workarounds. We override certain hc_driver functions here to
         * achieve that. We explicitly do not enhance ehci_driver_overrides to
         * allow this more easily, since this is an unusual case, and we don't
         * want to encourage others to override these functions by making it
         * too easy.
         */

        tegra_ehci_hc_driver.map_urb_for_dma = tegra_ehci_map_urb_for_dma;
        tegra_ehci_hc_driver.unmap_urb_for_dma = tegra_ehci_unmap_urb_for_dma;
        tegra_ehci_hc_driver.hub_control = tegra_ehci_hub_control;

        return platform_driver_register(&tegra_ehci_driver);
}
module_init(ehci_tegra_init);

static void __exit ehci_tegra_cleanup(void)
{
        platform_driver_unregister(&tegra_ehci_driver);
}
module_exit(ehci_tegra_cleanup);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);
MODULE_DEVICE_TABLE(of, tegra_ehci_of_match);