/**
 * core.c - DesignWare USB3 DRD Controller Core file
 *
 * Copyright (C) 2010-2011 Texas Instruments Incorporated - http://www.ti.com
 *
 * Authors: Felipe Balbi <balbi@ti.com>,
 *          Sebastian Andrzej Siewior <bigeasy@linutronix.de>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The names of the above-listed copyright holders may not be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * ALTERNATIVELY, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2, as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/list.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/of.h>

#include <linux/usb/otg.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>

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

#include "debug.h"

static char *maximum_speed = "super";
module_param(maximum_speed, charp, 0);
MODULE_PARM_DESC(maximum_speed, "Maximum supported speed.");

/* -------------------------------------------------------------------------- */

void dwc3_set_mode(struct dwc3 *dwc, u32 mode)
{
        u32 reg;

        reg = dwc3_readl(dwc->regs, DWC3_GCTL);
        reg &= ~(DWC3_GCTL_PRTCAPDIR(DWC3_GCTL_PRTCAP_OTG));
        reg |= DWC3_GCTL_PRTCAPDIR(mode);
        dwc3_writel(dwc->regs, DWC3_GCTL, reg);
}

/**
 * dwc3_core_soft_reset - Issues core soft reset and PHY reset
 * @dwc: pointer to our context structure
 */
static void dwc3_core_soft_reset(struct dwc3 *dwc)
{
        u32             reg;

        /* Before Resetting PHY, put Core in Reset */
        reg = dwc3_readl(dwc->regs, DWC3_GCTL);
        reg |= DWC3_GCTL_CORESOFTRESET;
        dwc3_writel(dwc->regs, DWC3_GCTL, reg);

        /* Assert USB3 PHY reset */
        reg = dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0));
        reg |= DWC3_GUSB3PIPECTL_PHYSOFTRST;
        dwc3_writel(dwc->regs, DWC3_GUSB3PIPECTL(0), reg);

        /* Assert USB2 PHY reset */
        reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
        reg |= DWC3_GUSB2PHYCFG_PHYSOFTRST;
        dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);

        usb_phy_init(dwc->usb2_phy);
        usb_phy_init(dwc->usb3_phy);
        mdelay(100);

        /* Clear USB3 PHY reset */
        reg = dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0));
        reg &= ~DWC3_GUSB3PIPECTL_PHYSOFTRST;
        dwc3_writel(dwc->regs, DWC3_GUSB3PIPECTL(0), reg);

        /* Clear USB2 PHY reset */
        reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
        reg &= ~DWC3_GUSB2PHYCFG_PHYSOFTRST;
        dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);

        mdelay(100);

        /* After PHYs are stable we can take Core out of reset state */
        reg = dwc3_readl(dwc->regs, DWC3_GCTL);
        reg &= ~DWC3_GCTL_CORESOFTRESET;
        dwc3_writel(dwc->regs, DWC3_GCTL, reg);
}

/**
 * dwc3_free_one_event_buffer - Frees one event buffer
 * @dwc: Pointer to our controller context structure
 * @evt: Pointer to event buffer to be freed
 */
static void dwc3_free_one_event_buffer(struct dwc3 *dwc,
                struct dwc3_event_buffer *evt)
{
        dma_free_coherent(dwc->dev, evt->length, evt->buf, evt->dma);
}

/**
 * dwc3_alloc_one_event_buffer - Allocates one event buffer structure
 * @dwc: Pointer to our controller context structure
 * @length: size of the event buffer
 *
 * Returns a pointer to the allocated event buffer structure on success
 * otherwise ERR_PTR(errno).
 */
static struct dwc3_event_buffer *dwc3_alloc_one_event_buffer(struct dwc3 *dwc, unsigned length)
{
        struct dwc3_event_buffer        *evt;

        evt = devm_kzalloc(dwc->dev, sizeof(*evt), GFP_KERNEL);
        if (!evt)
                return ERR_PTR(-ENOMEM);

        evt->dwc        = dwc;
        evt->length     = length;
        evt->buf        = dma_alloc_coherent(dwc->dev, length,
                        &evt->dma, GFP_KERNEL);
        if (!evt->buf)
                return ERR_PTR(-ENOMEM);

        return evt;
}

/**
 * dwc3_free_event_buffers - frees all allocated event buffers
 * @dwc: Pointer to our controller context structure
 */
static void dwc3_free_event_buffers(struct dwc3 *dwc)
{
        struct dwc3_event_buffer        *evt;
        int i;

        for (i = 0; i < dwc->num_event_buffers; i++) {
                evt = dwc->ev_buffs[i];
                if (evt)
                        dwc3_free_one_event_buffer(dwc, evt);
        }
}

/**
 * dwc3_alloc_event_buffers - Allocates @num event buffers of size @length
 * @dwc: pointer to our controller context structure
 * @length: size of event buffer
 *
 * Returns 0 on success otherwise negative errno. In the error case, dwc
 * may contain some buffers allocated but not all which were requested.
 */
static int dwc3_alloc_event_buffers(struct dwc3 *dwc, unsigned length)
{
        int                     num;
        int                     i;

        num = DWC3_NUM_INT(dwc->hwparams.hwparams1);
        dwc->num_event_buffers = num;

        dwc->ev_buffs = devm_kzalloc(dwc->dev, sizeof(*dwc->ev_buffs) * num,
                        GFP_KERNEL);
        if (!dwc->ev_buffs) {
                dev_err(dwc->dev, "can't allocate event buffers array\n");
                return -ENOMEM;
        }

        for (i = 0; i < num; i++) {
                struct dwc3_event_buffer        *evt;

                evt = dwc3_alloc_one_event_buffer(dwc, length);
                if (IS_ERR(evt)) {
                        dev_err(dwc->dev, "can't allocate event buffer\n");
                        return PTR_ERR(evt);
                }
                dwc->ev_buffs[i] = evt;
        }

        return 0;
}

/**
 * dwc3_event_buffers_setup - setup our allocated event buffers
 * @dwc: pointer to our controller context structure
 *
 * Returns 0 on success otherwise negative errno.
 */
static int dwc3_event_buffers_setup(struct dwc3 *dwc)
{
        struct dwc3_event_buffer        *evt;
        int                             n;

        for (n = 0; n < dwc->num_event_buffers; n++) {
                evt = dwc->ev_buffs[n];
                dev_dbg(dwc->dev, "Event buf %p dma %08llx length %d\n",
                                evt->buf, (unsigned long long) evt->dma,
                                evt->length);

                evt->lpos = 0;

                dwc3_writel(dwc->regs, DWC3_GEVNTADRLO(n),
                                lower_32_bits(evt->dma));
                dwc3_writel(dwc->regs, DWC3_GEVNTADRHI(n),
                                upper_32_bits(evt->dma));
                dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(n),
                                evt->length & 0xffff);
                dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(n), 0);
        }

        return 0;
}

static void dwc3_event_buffers_cleanup(struct dwc3 *dwc)
{
        struct dwc3_event_buffer        *evt;
        int                             n;

        for (n = 0; n < dwc->num_event_buffers; n++) {
                evt = dwc->ev_buffs[n];

                evt->lpos = 0;

                dwc3_writel(dwc->regs, DWC3_GEVNTADRLO(n), 0);
                dwc3_writel(dwc->regs, DWC3_GEVNTADRHI(n), 0);
                dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(n), 0);
                dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(n), 0);
        }
}

static void dwc3_cache_hwparams(struct dwc3 *dwc)
{
        struct dwc3_hwparams    *parms = &dwc->hwparams;

        parms->hwparams0 = dwc3_readl(dwc->regs, DWC3_GHWPARAMS0);
        parms->hwparams1 = dwc3_readl(dwc->regs, DWC3_GHWPARAMS1);
        parms->hwparams2 = dwc3_readl(dwc->regs, DWC3_GHWPARAMS2);
        parms->hwparams3 = dwc3_readl(dwc->regs, DWC3_GHWPARAMS3);
        parms->hwparams4 = dwc3_readl(dwc->regs, DWC3_GHWPARAMS4);
        parms->hwparams5 = dwc3_readl(dwc->regs, DWC3_GHWPARAMS5);
        parms->hwparams6 = dwc3_readl(dwc->regs, DWC3_GHWPARAMS6);
        parms->hwparams7 = dwc3_readl(dwc->regs, DWC3_GHWPARAMS7);
        parms->hwparams8 = dwc3_readl(dwc->regs, DWC3_GHWPARAMS8);
}

/**
 * dwc3_core_init - Low-level initialization of DWC3 Core
 * @dwc: Pointer to our controller context structure
 *
 * Returns 0 on success otherwise negative errno.
 */
static int dwc3_core_init(struct dwc3 *dwc)
{
        unsigned long           timeout;
        u32                     reg;
        int                     ret;

        reg = dwc3_readl(dwc->regs, DWC3_GSNPSID);
        /* This should read as U3 followed by revision number */
        if ((reg & DWC3_GSNPSID_MASK) != 0x55330000) {
                dev_err(dwc->dev, "this is not a DesignWare USB3 DRD Core\n");
                ret = -ENODEV;
                goto err0;
        }
        dwc->revision = reg;

        /* issue device SoftReset too */
        timeout = jiffies + msecs_to_jiffies(500);
        dwc3_writel(dwc->regs, DWC3_DCTL, DWC3_DCTL_CSFTRST);
        do {
                reg = dwc3_readl(dwc->regs, DWC3_DCTL);
                if (!(reg & DWC3_DCTL_CSFTRST))
                        break;

                if (time_after(jiffies, timeout)) {
                        dev_err(dwc->dev, "Reset Timed Out\n");
                        ret = -ETIMEDOUT;
                        goto err0;
                }

                cpu_relax();
        } while (true);

        dwc3_core_soft_reset(dwc);

        reg = dwc3_readl(dwc->regs, DWC3_GCTL);
        reg &= ~DWC3_GCTL_SCALEDOWN_MASK;
        reg &= ~DWC3_GCTL_DISSCRAMBLE;

        switch (DWC3_GHWPARAMS1_EN_PWROPT(dwc->hwparams.hwparams1)) {
        case DWC3_GHWPARAMS1_EN_PWROPT_CLK:
                reg &= ~DWC3_GCTL_DSBLCLKGTNG;
                break;
        default:
                dev_dbg(dwc->dev, "No power optimization available\n");
        }

        /*
         * WORKAROUND: DWC3 revisions <1.90a have a bug
         * where the device can fail to connect at SuperSpeed
         * and falls back to high-speed mode which causes
         * the device to enter a Connect/Disconnect loop
         */
        if (dwc->revision < DWC3_REVISION_190A)
                reg |= DWC3_GCTL_U2RSTECN;

        dwc3_writel(dwc->regs, DWC3_GCTL, reg);

        ret = dwc3_event_buffers_setup(dwc);
        if (ret) {
                dev_err(dwc->dev, "failed to setup event buffers\n");
                goto err0;
        }

        return 0;

err0:
        return ret;
}

static void dwc3_core_exit(struct dwc3 *dwc)
{
        dwc3_event_buffers_cleanup(dwc);

        usb_phy_shutdown(dwc->usb2_phy);
        usb_phy_shutdown(dwc->usb3_phy);
}

#define DWC3_ALIGN_MASK         (16 - 1)

static int dwc3_probe(struct platform_device *pdev)
{
        struct device_node      *node = pdev->dev.of_node;
        struct resource         *res;
        struct dwc3             *dwc;
        struct device           *dev = &pdev->dev;

        int                     ret = -ENOMEM;

        void __iomem            *regs;
        void                    *mem;

        u8                      mode;

        mem = devm_kzalloc(dev, sizeof(*dwc) + DWC3_ALIGN_MASK, GFP_KERNEL);
        if (!mem) {
                dev_err(dev, "not enough memory\n");
                return -ENOMEM;
        }
        dwc = PTR_ALIGN(mem, DWC3_ALIGN_MASK + 1);
        dwc->mem = mem;

        res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
        if (!res) {
                dev_err(dev, "missing IRQ\n");
                return -ENODEV;
        }
        dwc->xhci_resources[1].start = res->start;
        dwc->xhci_resources[1].end = res->end;
        dwc->xhci_resources[1].flags = res->flags;
        dwc->xhci_resources[1].name = res->name;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                dev_err(dev, "missing memory resource\n");
                return -ENODEV;
        }
        dwc->xhci_resources[0].start = res->start;
        dwc->xhci_resources[0].end = dwc->xhci_resources[0].start +
                                        DWC3_XHCI_REGS_END;
        dwc->xhci_resources[0].flags = res->flags;
        dwc->xhci_resources[0].name = res->name;

         /*
          * Request memory region but exclude xHCI regs,
          * since it will be requested by the xhci-plat driver.
          */
        res = devm_request_mem_region(dev, res->start + DWC3_GLOBALS_REGS_START,
                        resource_size(res) - DWC3_GLOBALS_REGS_START,
                        dev_name(dev));
        if (!res) {
                dev_err(dev, "can't request mem region\n");
                return -ENOMEM;
        }

        regs = devm_ioremap_nocache(dev, res->start, resource_size(res));
        if (!regs) {
                dev_err(dev, "ioremap failed\n");
                return -ENOMEM;
        }

        if (node) {
                dwc->usb2_phy = devm_usb_get_phy_by_phandle(dev, "usb-phy", 0);
                dwc->usb3_phy = devm_usb_get_phy_by_phandle(dev, "usb-phy", 1);
        } else {
                dwc->usb2_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB2);
                dwc->usb3_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB3);
        }

        if (IS_ERR_OR_NULL(dwc->usb2_phy)) {
                dev_err(dev, "no usb2 phy configured\n");
                return -EPROBE_DEFER;
        }

        if (IS_ERR_OR_NULL(dwc->usb3_phy)) {
                dev_err(dev, "no usb3 phy configured\n");
                return -EPROBE_DEFER;
        }

        usb_phy_set_suspend(dwc->usb2_phy, 0);
        usb_phy_set_suspend(dwc->usb3_phy, 0);

        spin_lock_init(&dwc->lock);
        platform_set_drvdata(pdev, dwc);

        dwc->regs       = regs;
        dwc->regs_size  = resource_size(res);
        dwc->dev        = dev;

        if (!strncmp("super", maximum_speed, 5))
                dwc->maximum_speed = DWC3_DCFG_SUPERSPEED;
        else if (!strncmp("high", maximum_speed, 4))
                dwc->maximum_speed = DWC3_DCFG_HIGHSPEED;
        else if (!strncmp("full", maximum_speed, 4))
                dwc->maximum_speed = DWC3_DCFG_FULLSPEED1;
        else if (!strncmp("low", maximum_speed, 3))
                dwc->maximum_speed = DWC3_DCFG_LOWSPEED;
        else
                dwc->maximum_speed = DWC3_DCFG_SUPERSPEED;

        dwc->needs_fifo_resize = of_property_read_bool(node, "tx-fifo-resize");

        pm_runtime_enable(dev);
        pm_runtime_get_sync(dev);
        pm_runtime_forbid(dev);

        dwc3_cache_hwparams(dwc);

        ret = dwc3_alloc_event_buffers(dwc, DWC3_EVENT_BUFFERS_SIZE);
        if (ret) {
                dev_err(dwc->dev, "failed to allocate event buffers\n");
                ret = -ENOMEM;
                goto err0;
        }

        ret = dwc3_core_init(dwc);
        if (ret) {
                dev_err(dev, "failed to initialize core\n");
                goto err0;
        }

        mode = DWC3_MODE(dwc->hwparams.hwparams0);

        switch (mode) {
        case DWC3_MODE_DEVICE:
                dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
                ret = dwc3_gadget_init(dwc);
                if (ret) {
                        dev_err(dev, "failed to initialize gadget\n");
                        goto err1;
                }
                break;
        case DWC3_MODE_HOST:
                dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_HOST);
                ret = dwc3_host_init(dwc);
                if (ret) {
                        dev_err(dev, "failed to initialize host\n");
                        goto err1;
                }
                break;
        case DWC3_MODE_DRD:
                dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG);
                ret = dwc3_host_init(dwc);
                if (ret) {
                        dev_err(dev, "failed to initialize host\n");
                        goto err1;
                }

                ret = dwc3_gadget_init(dwc);
                if (ret) {
                        dev_err(dev, "failed to initialize gadget\n");
                        goto err1;
                }
                break;
        default:
                dev_err(dev, "Unsupported mode of operation %d\n", mode);
                goto err1;
        }
        dwc->mode = mode;

        ret = dwc3_debugfs_init(dwc);
        if (ret) {
                dev_err(dev, "failed to initialize debugfs\n");
                goto err2;
        }

        pm_runtime_allow(dev);

        return 0;

err2:
        switch (mode) {
        case DWC3_MODE_DEVICE:
                dwc3_gadget_exit(dwc);
                break;
        case DWC3_MODE_HOST:
                dwc3_host_exit(dwc);
                break;
        case DWC3_MODE_DRD:
                dwc3_host_exit(dwc);
                dwc3_gadget_exit(dwc);
                break;
        default:
                /* do nothing */
                break;
        }

err1:
        dwc3_core_exit(dwc);

err0:
        dwc3_free_event_buffers(dwc);

        return ret;
}

static int dwc3_remove(struct platform_device *pdev)
{
        struct dwc3     *dwc = platform_get_drvdata(pdev);

        usb_phy_set_suspend(dwc->usb2_phy, 1);
        usb_phy_set_suspend(dwc->usb3_phy, 1);

        pm_runtime_put(&pdev->dev);
        pm_runtime_disable(&pdev->dev);

        dwc3_debugfs_exit(dwc);

        switch (dwc->mode) {
        case DWC3_MODE_DEVICE:
                dwc3_gadget_exit(dwc);
                break;
        case DWC3_MODE_HOST:
                dwc3_host_exit(dwc);
                break;
        case DWC3_MODE_DRD:
                dwc3_host_exit(dwc);
                dwc3_gadget_exit(dwc);
                break;
        default:
                /* do nothing */
                break;
        }

        dwc3_free_event_buffers(dwc);
        dwc3_core_exit(dwc);

        return 0;
}

#ifdef CONFIG_OF
static const struct of_device_id of_dwc3_match[] = {
        {
                .compatible = "synopsys,dwc3"
        },
        { },
};
MODULE_DEVICE_TABLE(of, of_dwc3_match);
#endif

static struct platform_driver dwc3_driver = {
        .probe          = dwc3_probe,
        .remove         = dwc3_remove,
        .driver         = {
                .name   = "dwc3",
                .of_match_table = of_match_ptr(of_dwc3_match),
        },
};

module_platform_driver(dwc3_driver);

MODULE_ALIAS("platform:dwc3");
MODULE_AUTHOR("Felipe Balbi <balbi@ti.com>");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("DesignWare USB3 DRD Controller Driver");