/*
 * Texas Instruments DA8xx/OMAP-L1x "glue layer"
 *
 * Copyright (c) 2008-2009 MontaVista Software, Inc. <source@mvista.com>
 *
 * Based on the DaVinci "glue layer" code.
 * Copyright (C) 2005-2006 by Texas Instruments
 *
 * This file is part of the Inventra Controller Driver for Linux.
 *
 * The Inventra Controller Driver for Linux is free software; you
 * can redistribute it and/or modify it under the terms of the GNU
 * General Public License version 2 as published by the Free Software
 * Foundation.
 *
 * The Inventra Controller Driver for Linux 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with The Inventra Controller Driver for Linux ; if not,
 * write to the Free Software Foundation, Inc., 59 Temple Place,
 * Suite 330, Boston, MA  02111-1307  USA
 *
 */

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

#include <mach/da8xx.h>
#include <linux/platform_data/usb-davinci.h>

#include "musb_core.h"

/*
 * DA8XX specific definitions
 */

/* USB 2.0 OTG module registers */
#define DA8XX_USB_REVISION_REG  0x00
#define DA8XX_USB_CTRL_REG      0x04
#define DA8XX_USB_STAT_REG      0x08
#define DA8XX_USB_EMULATION_REG 0x0c
#define DA8XX_USB_MODE_REG      0x10    /* Transparent, CDC, [Generic] RNDIS */
#define DA8XX_USB_AUTOREQ_REG   0x14
#define DA8XX_USB_SRP_FIX_TIME_REG 0x18
#define DA8XX_USB_TEARDOWN_REG  0x1c
#define DA8XX_USB_INTR_SRC_REG  0x20
#define DA8XX_USB_INTR_SRC_SET_REG 0x24
#define DA8XX_USB_INTR_SRC_CLEAR_REG 0x28
#define DA8XX_USB_INTR_MASK_REG 0x2c
#define DA8XX_USB_INTR_MASK_SET_REG 0x30
#define DA8XX_USB_INTR_MASK_CLEAR_REG 0x34
#define DA8XX_USB_INTR_SRC_MASKED_REG 0x38
#define DA8XX_USB_END_OF_INTR_REG 0x3c
#define DA8XX_USB_GENERIC_RNDIS_EP_SIZE_REG(n) (0x50 + (((n) - 1) << 2))

/* Control register bits */
#define DA8XX_SOFT_RESET_MASK   1

#define DA8XX_USB_TX_EP_MASK    0x1f            /* EP0 + 4 Tx EPs */
#define DA8XX_USB_RX_EP_MASK    0x1e            /* 4 Rx EPs */

/* USB interrupt register bits */
#define DA8XX_INTR_USB_SHIFT    16
#define DA8XX_INTR_USB_MASK     (0x1ff << DA8XX_INTR_USB_SHIFT) /* 8 Mentor */
                                        /* interrupts and DRVVBUS interrupt */
#define DA8XX_INTR_DRVVBUS      0x100
#define DA8XX_INTR_RX_SHIFT     8
#define DA8XX_INTR_RX_MASK      (DA8XX_USB_RX_EP_MASK << DA8XX_INTR_RX_SHIFT)
#define DA8XX_INTR_TX_SHIFT     0
#define DA8XX_INTR_TX_MASK      (DA8XX_USB_TX_EP_MASK << DA8XX_INTR_TX_SHIFT)

#define DA8XX_MENTOR_CORE_OFFSET 0x400

#define CFGCHIP2        IO_ADDRESS(DA8XX_SYSCFG0_BASE + DA8XX_CFGCHIP2_REG)

struct da8xx_glue {
        struct device           *dev;
        struct platform_device  *musb;
        struct clk              *clk;
};

/*
 * REVISIT (PM): we should be able to keep the PHY in low power mode most
 * of the time (24 MHz oscillator and PLL off, etc.) by setting POWER.D0
 * and, when in host mode, autosuspending idle root ports... PHY_PLLON
 * (overriding SUSPENDM?) then likely needs to stay off.
 */

static inline void phy_on(void)
{
        u32 cfgchip2 = __raw_readl(CFGCHIP2);

        /*
         * Start the on-chip PHY and its PLL.
         */
        cfgchip2 &= ~(CFGCHIP2_RESET | CFGCHIP2_PHYPWRDN | CFGCHIP2_OTGPWRDN);
        cfgchip2 |= CFGCHIP2_PHY_PLLON;
        __raw_writel(cfgchip2, CFGCHIP2);

        pr_info("Waiting for USB PHY clock good...\n");
        while (!(__raw_readl(CFGCHIP2) & CFGCHIP2_PHYCLKGD))
                cpu_relax();
}

static inline void phy_off(void)
{
        u32 cfgchip2 = __raw_readl(CFGCHIP2);

        /*
         * Ensure that USB 1.1 reference clock is not being sourced from
         * USB 2.0 PHY.  Otherwise do not power down the PHY.
         */
        if (!(cfgchip2 & CFGCHIP2_USB1PHYCLKMUX) &&
             (cfgchip2 & CFGCHIP2_USB1SUSPENDM)) {
                pr_warning("USB 1.1 clocked from USB 2.0 PHY -- "
                           "can't power it down\n");
                return;
        }

        /*
         * Power down the on-chip PHY.
         */
        cfgchip2 |= CFGCHIP2_PHYPWRDN | CFGCHIP2_OTGPWRDN;
        __raw_writel(cfgchip2, CFGCHIP2);
}

/*
 * Because we don't set CTRL.UINT, it's "important" to:
 *      - not read/write INTRUSB/INTRUSBE (except during
 *        initial setup, as a workaround);
 *      - use INTSET/INTCLR instead.
 */

/**
 * da8xx_musb_enable - enable interrupts
 */
static void da8xx_musb_enable(struct musb *musb)
{
        void __iomem *reg_base = musb->ctrl_base;
        u32 mask;

        /* Workaround: setup IRQs through both register sets. */
        mask = ((musb->epmask & DA8XX_USB_TX_EP_MASK) << DA8XX_INTR_TX_SHIFT) |
               ((musb->epmask & DA8XX_USB_RX_EP_MASK) << DA8XX_INTR_RX_SHIFT) |
               DA8XX_INTR_USB_MASK;
        musb_writel(reg_base, DA8XX_USB_INTR_MASK_SET_REG, mask);

        /* Force the DRVVBUS IRQ so we can start polling for ID change. */
        musb_writel(reg_base, DA8XX_USB_INTR_SRC_SET_REG,
                        DA8XX_INTR_DRVVBUS << DA8XX_INTR_USB_SHIFT);
}

/**
 * da8xx_musb_disable - disable HDRC and flush interrupts
 */
static void da8xx_musb_disable(struct musb *musb)
{
        void __iomem *reg_base = musb->ctrl_base;

        musb_writel(reg_base, DA8XX_USB_INTR_MASK_CLEAR_REG,
                    DA8XX_INTR_USB_MASK |
                    DA8XX_INTR_TX_MASK | DA8XX_INTR_RX_MASK);
        musb_writeb(musb->mregs, MUSB_DEVCTL, 0);
        musb_writel(reg_base, DA8XX_USB_END_OF_INTR_REG, 0);
}

#define portstate(stmt)         stmt

static void da8xx_musb_set_vbus(struct musb *musb, int is_on)
{
        WARN_ON(is_on && is_peripheral_active(musb));
}

#define POLL_SECONDS    2

static struct timer_list otg_workaround;

static void otg_timer(unsigned long _musb)
{
        struct musb             *musb = (void *)_musb;
        void __iomem            *mregs = musb->mregs;
        u8                      devctl;
        unsigned long           flags;

        /*
         * We poll because DaVinci's won't expose several OTG-critical
         * status change events (from the transceiver) otherwise.
         */
        devctl = musb_readb(mregs, MUSB_DEVCTL);
        dev_dbg(musb->controller, "Poll devctl %02x (%s)\n", devctl,
                usb_otg_state_string(musb->xceiv->state));

        spin_lock_irqsave(&musb->lock, flags);
        switch (musb->xceiv->state) {
        case OTG_STATE_A_WAIT_BCON:
                devctl &= ~MUSB_DEVCTL_SESSION;
                musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);

                devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
                if (devctl & MUSB_DEVCTL_BDEVICE) {
                        musb->xceiv->state = OTG_STATE_B_IDLE;
                        MUSB_DEV_MODE(musb);
                } else {
                        musb->xceiv->state = OTG_STATE_A_IDLE;
                        MUSB_HST_MODE(musb);
                }
                break;
        case OTG_STATE_A_WAIT_VFALL:
                /*
                 * Wait till VBUS falls below SessionEnd (~0.2 V); the 1.3
                 * RTL seems to mis-handle session "start" otherwise (or in
                 * our case "recover"), in routine "VBUS was valid by the time
                 * VBUSERR got reported during enumeration" cases.
                 */
                if (devctl & MUSB_DEVCTL_VBUS) {
                        mod_timer(&otg_workaround, jiffies + POLL_SECONDS * HZ);
                        break;
                }
                musb->xceiv->state = OTG_STATE_A_WAIT_VRISE;
                musb_writel(musb->ctrl_base, DA8XX_USB_INTR_SRC_SET_REG,
                            MUSB_INTR_VBUSERROR << DA8XX_INTR_USB_SHIFT);
                break;
        case OTG_STATE_B_IDLE:
                /*
                 * There's no ID-changed IRQ, so we have no good way to tell
                 * when to switch to the A-Default state machine (by setting
                 * the DEVCTL.Session bit).
                 *
                 * Workaround:  whenever we're in B_IDLE, try setting the
                 * session flag every few seconds.  If it works, ID was
                 * grounded and we're now in the A-Default state machine.
                 *
                 * NOTE: setting the session flag is _supposed_ to trigger
                 * SRP but clearly it doesn't.
                 */
                musb_writeb(mregs, MUSB_DEVCTL, devctl | MUSB_DEVCTL_SESSION);
                devctl = musb_readb(mregs, MUSB_DEVCTL);
                if (devctl & MUSB_DEVCTL_BDEVICE)
                        mod_timer(&otg_workaround, jiffies + POLL_SECONDS * HZ);
                else
                        musb->xceiv->state = OTG_STATE_A_IDLE;
                break;
        default:
                break;
        }
        spin_unlock_irqrestore(&musb->lock, flags);
}

static void da8xx_musb_try_idle(struct musb *musb, unsigned long timeout)
{
        static unsigned long last_timer;

        if (timeout == 0)
                timeout = jiffies + msecs_to_jiffies(3);

        /* Never idle if active, or when VBUS timeout is not set as host */
        if (musb->is_active || (musb->a_wait_bcon == 0 &&
                                musb->xceiv->state == OTG_STATE_A_WAIT_BCON)) {
                dev_dbg(musb->controller, "%s active, deleting timer\n",
                        usb_otg_state_string(musb->xceiv->state));
                del_timer(&otg_workaround);
                last_timer = jiffies;
                return;
        }

        if (time_after(last_timer, timeout) && timer_pending(&otg_workaround)) {
                dev_dbg(musb->controller, "Longer idle timer already pending, ignoring...\n");
                return;
        }
        last_timer = timeout;

        dev_dbg(musb->controller, "%s inactive, starting idle timer for %u ms\n",
                usb_otg_state_string(musb->xceiv->state),
                jiffies_to_msecs(timeout - jiffies));
        mod_timer(&otg_workaround, timeout);
}

static irqreturn_t da8xx_musb_interrupt(int irq, void *hci)
{
        struct musb             *musb = hci;
        void __iomem            *reg_base = musb->ctrl_base;
        struct usb_otg          *otg = musb->xceiv->otg;
        unsigned long           flags;
        irqreturn_t             ret = IRQ_NONE;
        u32                     status;

        spin_lock_irqsave(&musb->lock, flags);

        /*
         * NOTE: DA8XX shadows the Mentor IRQs.  Don't manage them through
         * the Mentor registers (except for setup), use the TI ones and EOI.
         */

        /* Acknowledge and handle non-CPPI interrupts */
        status = musb_readl(reg_base, DA8XX_USB_INTR_SRC_MASKED_REG);
        if (!status)
                goto eoi;

        musb_writel(reg_base, DA8XX_USB_INTR_SRC_CLEAR_REG, status);
        dev_dbg(musb->controller, "USB IRQ %08x\n", status);

        musb->int_rx = (status & DA8XX_INTR_RX_MASK) >> DA8XX_INTR_RX_SHIFT;
        musb->int_tx = (status & DA8XX_INTR_TX_MASK) >> DA8XX_INTR_TX_SHIFT;
        musb->int_usb = (status & DA8XX_INTR_USB_MASK) >> DA8XX_INTR_USB_SHIFT;

        /*
         * DRVVBUS IRQs are the only proxy we have (a very poor one!) for
         * DA8xx's missing ID change IRQ.  We need an ID change IRQ to
         * switch appropriately between halves of the OTG state machine.
         * Managing DEVCTL.Session per Mentor docs requires that we know its
         * value but DEVCTL.BDevice is invalid without DEVCTL.Session set.
         * Also, DRVVBUS pulses for SRP (but not at 5 V)...
         */
        if (status & (DA8XX_INTR_DRVVBUS << DA8XX_INTR_USB_SHIFT)) {
                int drvvbus = musb_readl(reg_base, DA8XX_USB_STAT_REG);
                void __iomem *mregs = musb->mregs;
                u8 devctl = musb_readb(mregs, MUSB_DEVCTL);
                int err;

                err = musb->int_usb & MUSB_INTR_VBUSERROR;
                if (err) {
                        /*
                         * The Mentor core doesn't debounce VBUS as needed
                         * to cope with device connect current spikes. This
                         * means it's not uncommon for bus-powered devices
                         * to get VBUS errors during enumeration.
                         *
                         * This is a workaround, but newer RTL from Mentor
                         * seems to allow a better one: "re"-starting sessions
                         * without waiting for VBUS to stop registering in
                         * devctl.
                         */
                        musb->int_usb &= ~MUSB_INTR_VBUSERROR;
                        musb->xceiv->state = OTG_STATE_A_WAIT_VFALL;
                        mod_timer(&otg_workaround, jiffies + POLL_SECONDS * HZ);
                        WARNING("VBUS error workaround (delay coming)\n");
                } else if (drvvbus) {
                        MUSB_HST_MODE(musb);
                        otg->default_a = 1;
                        musb->xceiv->state = OTG_STATE_A_WAIT_VRISE;
                        portstate(musb->port1_status |= USB_PORT_STAT_POWER);
                        del_timer(&otg_workaround);
                } else {
                        musb->is_active = 0;
                        MUSB_DEV_MODE(musb);
                        otg->default_a = 0;
                        musb->xceiv->state = OTG_STATE_B_IDLE;
                        portstate(musb->port1_status &= ~USB_PORT_STAT_POWER);
                }

                dev_dbg(musb->controller, "VBUS %s (%s)%s, devctl %02x\n",
                                drvvbus ? "on" : "off",
                                usb_otg_state_string(musb->xceiv->state),
                                err ? " ERROR" : "",
                                devctl);
                ret = IRQ_HANDLED;
        }

        if (musb->int_tx || musb->int_rx || musb->int_usb)
                ret |= musb_interrupt(musb);

 eoi:
        /* EOI needs to be written for the IRQ to be re-asserted. */
        if (ret == IRQ_HANDLED || status)
                musb_writel(reg_base, DA8XX_USB_END_OF_INTR_REG, 0);

        /* Poll for ID change */
        if (musb->xceiv->state == OTG_STATE_B_IDLE)
                mod_timer(&otg_workaround, jiffies + POLL_SECONDS * HZ);

        spin_unlock_irqrestore(&musb->lock, flags);

        return ret;
}

static int da8xx_musb_set_mode(struct musb *musb, u8 musb_mode)
{
        u32 cfgchip2 = __raw_readl(CFGCHIP2);

        cfgchip2 &= ~CFGCHIP2_OTGMODE;
        switch (musb_mode) {
        case MUSB_HOST:         /* Force VBUS valid, ID = 0 */
                cfgchip2 |= CFGCHIP2_FORCE_HOST;
                break;
        case MUSB_PERIPHERAL:   /* Force VBUS valid, ID = 1 */
                cfgchip2 |= CFGCHIP2_FORCE_DEVICE;
                break;
        case MUSB_OTG:          /* Don't override the VBUS/ID comparators */
                cfgchip2 |= CFGCHIP2_NO_OVERRIDE;
                break;
        default:
                dev_dbg(musb->controller, "Trying to set unsupported mode %u\n", musb_mode);
        }

        __raw_writel(cfgchip2, CFGCHIP2);
        return 0;
}

static int da8xx_musb_init(struct musb *musb)
{
        void __iomem *reg_base = musb->ctrl_base;
        u32 rev;
        int ret = -ENODEV;

        musb->mregs += DA8XX_MENTOR_CORE_OFFSET;

        /* Returns zero if e.g. not clocked */
        rev = musb_readl(reg_base, DA8XX_USB_REVISION_REG);
        if (!rev)
                goto fail;

        usb_nop_xceiv_register();
        musb->xceiv = usb_get_phy(USB_PHY_TYPE_USB2);
        if (IS_ERR_OR_NULL(musb->xceiv)) {
                ret = -EPROBE_DEFER;
                goto fail;
        }

        setup_timer(&otg_workaround, otg_timer, (unsigned long)musb);

        /* Reset the controller */
        musb_writel(reg_base, DA8XX_USB_CTRL_REG, DA8XX_SOFT_RESET_MASK);

        /* Start the on-chip PHY and its PLL. */
        phy_on();

        msleep(5);

        /* NOTE: IRQs are in mixed mode, not bypass to pure MUSB */
        pr_debug("DA8xx OTG revision %08x, PHY %03x, control %02x\n",
                 rev, __raw_readl(CFGCHIP2),
                 musb_readb(reg_base, DA8XX_USB_CTRL_REG));

        musb->isr = da8xx_musb_interrupt;
        return 0;
fail:
        return ret;
}

static int da8xx_musb_exit(struct musb *musb)
{
        del_timer_sync(&otg_workaround);

        phy_off();

        usb_put_phy(musb->xceiv);
        usb_nop_xceiv_unregister();

        return 0;
}

static const struct musb_platform_ops da8xx_ops = {
        .init           = da8xx_musb_init,
        .exit           = da8xx_musb_exit,

        .enable         = da8xx_musb_enable,
        .disable        = da8xx_musb_disable,

        .set_mode       = da8xx_musb_set_mode,
        .try_idle       = da8xx_musb_try_idle,

        .set_vbus       = da8xx_musb_set_vbus,
};

static const struct platform_device_info da8xx_dev_info = {
        .name           = "musb-hdrc",
        .id             = PLATFORM_DEVID_AUTO,
        .dma_mask       = DMA_BIT_MASK(32),
};

static int da8xx_probe(struct platform_device *pdev)
{
        struct resource musb_resources[2];
        struct musb_hdrc_platform_data  *pdata = dev_get_platdata(&pdev->dev);
        struct platform_device          *musb;
        struct da8xx_glue               *glue;
        struct platform_device_info     pinfo;
        struct clk                      *clk;

        int                             ret = -ENOMEM;

        glue = kzalloc(sizeof(*glue), GFP_KERNEL);
        if (!glue) {
                dev_err(&pdev->dev, "failed to allocate glue context\n");
                goto err0;
        }

        clk = clk_get(&pdev->dev, "usb20");
        if (IS_ERR(clk)) {
                dev_err(&pdev->dev, "failed to get clock\n");
                ret = PTR_ERR(clk);
                goto err3;
        }

        ret = clk_enable(clk);
        if (ret) {
                dev_err(&pdev->dev, "failed to enable clock\n");
                goto err4;
        }

        glue->dev                       = &pdev->dev;
        glue->clk                       = clk;

        pdata->platform_ops             = &da8xx_ops;

        platform_set_drvdata(pdev, glue);

        memset(musb_resources, 0x00, sizeof(*musb_resources) *
                        ARRAY_SIZE(musb_resources));

        musb_resources[0].name = pdev->resource[0].name;
        musb_resources[0].start = pdev->resource[0].start;
        musb_resources[0].end = pdev->resource[0].end;
        musb_resources[0].flags = pdev->resource[0].flags;

        musb_resources[1].name = pdev->resource[1].name;
        musb_resources[1].start = pdev->resource[1].start;
        musb_resources[1].end = pdev->resource[1].end;
        musb_resources[1].flags = pdev->resource[1].flags;

        pinfo = da8xx_dev_info;
        pinfo.parent = &pdev->dev;
        pinfo.res = musb_resources;
        pinfo.num_res = ARRAY_SIZE(musb_resources);
        pinfo.data = pdata;
        pinfo.size_data = sizeof(*pdata);

        glue->musb = musb = platform_device_register_full(&pinfo);
        if (IS_ERR(musb)) {
                ret = PTR_ERR(musb);
                dev_err(&pdev->dev, "failed to register musb device: %d\n", ret);
                goto err5;
        }

        return 0;

err5:
        clk_disable(clk);

err4:
        clk_put(clk);

err3:
        kfree(glue);

err0:
        return ret;
}

static int da8xx_remove(struct platform_device *pdev)
{
        struct da8xx_glue               *glue = platform_get_drvdata(pdev);

        platform_device_unregister(glue->musb);
        clk_disable(glue->clk);
        clk_put(glue->clk);
        kfree(glue);

        return 0;
}

static struct platform_driver da8xx_driver = {
        .probe          = da8xx_probe,
        .remove         = da8xx_remove,
        .driver         = {
                .name   = "musb-da8xx",
        },
};

MODULE_DESCRIPTION("DA8xx/OMAP-L1x MUSB Glue Layer");
MODULE_AUTHOR("Sergei Shtylyov <sshtylyov@ru.mvista.com>");
MODULE_LICENSE("GPL v2");
module_platform_driver(da8xx_driver);