/*
 * 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/kernel.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/usb/nop-usb-xceiv.h>

#include <mach/cputype.h>
#include <mach/hardware.h>

#include <asm/mach-types.h>

#include "musb_core.h"

#ifdef CONFIG_MACH_DAVINCI_EVM
#define GPIO_nVBUS_DRV          160
#endif

#include "davinci.h"
#include "cppi_dma.h"


#define USB_PHY_CTRL    IO_ADDRESS(USBPHY_CTL_PADDR)
#define DM355_DEEPSLEEP IO_ADDRESS(DM355_DEEPSLEEP_PADDR)

struct davinci_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... PHYPLLON
 * (overriding SUSPENDM?) then likely needs to stay off.
 */

static inline void phy_on(void)
{
        u32     phy_ctrl = __raw_readl(USB_PHY_CTRL);

        /* power everything up; start the on-chip PHY and its PLL */
        phy_ctrl &= ~(USBPHY_OSCPDWN | USBPHY_OTGPDWN | USBPHY_PHYPDWN);
        phy_ctrl |= USBPHY_SESNDEN | USBPHY_VBDTCTEN | USBPHY_PHYPLLON;
        __raw_writel(phy_ctrl, USB_PHY_CTRL);

        /* wait for PLL to lock before proceeding */
        while ((__raw_readl(USB_PHY_CTRL) & USBPHY_PHYCLKGD) == 0)
                cpu_relax();
}

static inline void phy_off(void)
{
        u32     phy_ctrl = __raw_readl(USB_PHY_CTRL);

        /* powerdown the on-chip PHY, its PLL, and the OTG block */
        phy_ctrl &= ~(USBPHY_SESNDEN | USBPHY_VBDTCTEN | USBPHY_PHYPLLON);
        phy_ctrl |= USBPHY_OSCPDWN | USBPHY_OTGPDWN | USBPHY_PHYPDWN;
        __raw_writel(phy_ctrl, USB_PHY_CTRL);
}

static int dma_off = 1;

static void davinci_musb_enable(struct musb *musb)
{
        u32     tmp, old, val;

        /* workaround:  setup irqs through both register sets */
        tmp = (musb->epmask & DAVINCI_USB_TX_ENDPTS_MASK)
                        << DAVINCI_USB_TXINT_SHIFT;
        musb_writel(musb->ctrl_base, DAVINCI_USB_INT_MASK_SET_REG, tmp);
        old = tmp;
        tmp = (musb->epmask & (0xfffe & DAVINCI_USB_RX_ENDPTS_MASK))
                        << DAVINCI_USB_RXINT_SHIFT;
        musb_writel(musb->ctrl_base, DAVINCI_USB_INT_MASK_SET_REG, tmp);
        tmp |= old;

        val = ~MUSB_INTR_SOF;
        tmp |= ((val & 0x01ff) << DAVINCI_USB_USBINT_SHIFT);
        musb_writel(musb->ctrl_base, DAVINCI_USB_INT_MASK_SET_REG, tmp);

        if (is_dma_capable() && !dma_off)
                printk(KERN_WARNING "%s %s: dma not reactivated\n",
                                __FILE__, __func__);
        else
                dma_off = 0;

        /* force a DRVVBUS irq so we can start polling for ID change */
        musb_writel(musb->ctrl_base, DAVINCI_USB_INT_SET_REG,
                        DAVINCI_INTR_DRVVBUS << DAVINCI_USB_USBINT_SHIFT);
}

/*
 * Disable the HDRC and flush interrupts
 */
static void davinci_musb_disable(struct musb *musb)
{
        /* because we don't set CTRLR.UINT, "important" to:
         *  - not read/write INTRUSB/INTRUSBE
         *  - (except during initial setup, as workaround)
         *  - use INTSETR/INTCLRR instead
         */
        musb_writel(musb->ctrl_base, DAVINCI_USB_INT_MASK_CLR_REG,
                          DAVINCI_USB_USBINT_MASK
                        | DAVINCI_USB_TXINT_MASK
                        | DAVINCI_USB_RXINT_MASK);
        musb_writeb(musb->mregs, MUSB_DEVCTL, 0);
        musb_writel(musb->ctrl_base, DAVINCI_USB_EOI_REG, 0);

        if (is_dma_capable() && !dma_off)
                WARNING("dma still active\n");
}


#define portstate(stmt)         stmt

/*
 * VBUS SWITCHING IS BOARD-SPECIFIC ... at least for the DM6446 EVM,
 * which doesn't wire DRVVBUS to the FET that switches it.  Unclear
 * if that's a problem with the DM6446 chip or just with that board.
 *
 * In either case, the DM355 EVM automates DRVVBUS the normal way,
 * when J10 is out, and TI documents it as handling OTG.
 */

#ifdef CONFIG_MACH_DAVINCI_EVM

static int vbus_state = -1;

/* I2C operations are always synchronous, and require a task context.
 * With unloaded systems, using the shared workqueue seems to suffice
 * to satisfy the 100msec A_WAIT_VRISE timeout...
 */
static void evm_deferred_drvvbus(struct work_struct *ignored)
{
        gpio_set_value_cansleep(GPIO_nVBUS_DRV, vbus_state);
        vbus_state = !vbus_state;
}

#endif  /* EVM */

static void davinci_musb_source_power(struct musb *musb, int is_on, int immediate)
{
#ifdef CONFIG_MACH_DAVINCI_EVM
        if (is_on)
                is_on = 1;

        if (vbus_state == is_on)
                return;
        vbus_state = !is_on;            /* 0/1 vs "-1 == unknown/init" */

        if (machine_is_davinci_evm()) {
                static DECLARE_WORK(evm_vbus_work, evm_deferred_drvvbus);

                if (immediate)
                        gpio_set_value_cansleep(GPIO_nVBUS_DRV, vbus_state);
                else
                        schedule_work(&evm_vbus_work);
        }
        if (immediate)
                vbus_state = is_on;
#endif
}

static void davinci_musb_set_vbus(struct musb *musb, int is_on)
{
        WARN_ON(is_on && is_peripheral_active(musb));
        davinci_musb_source_power(musb, is_on, 0);
}


#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_VFALL:
                /* Wait till VBUS falls below SessionEnd (~0.2V); 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, DAVINCI_USB_INT_SET_REG,
                        MUSB_INTR_VBUSERROR << DAVINCI_USB_USBINT_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 flag).
                 *
                 * 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 irqreturn_t davinci_musb_interrupt(int irq, void *__hci)
{
        unsigned long   flags;
        irqreturn_t     retval = IRQ_NONE;
        struct musb     *musb = __hci;
        struct usb_otg  *otg = musb->xceiv->otg;
        void __iomem    *tibase = musb->ctrl_base;
        struct cppi     *cppi;
        u32             tmp;

        spin_lock_irqsave(&musb->lock, flags);

        /* NOTE: DaVinci shadows the Mentor IRQs.  Don't manage them through
         * the Mentor registers (except for setup), use the TI ones and EOI.
         *
         * Docs describe irq "vector" registers associated with the CPPI and
         * USB EOI registers.  These hold a bitmask corresponding to the
         * current IRQ, not an irq handler address.  Would using those bits
         * resolve some of the races observed in this dispatch code??
         */

        /* CPPI interrupts share the same IRQ line, but have their own
         * mask, state, "vector", and EOI registers.
         */
        cppi = container_of(musb->dma_controller, struct cppi, controller);
        if (is_cppi_enabled() && musb->dma_controller && !cppi->irq)
                retval = cppi_interrupt(irq, __hci);

        /* ack and handle non-CPPI interrupts */
        tmp = musb_readl(tibase, DAVINCI_USB_INT_SRC_MASKED_REG);
        musb_writel(tibase, DAVINCI_USB_INT_SRC_CLR_REG, tmp);
        dev_dbg(musb->controller, "IRQ %08x\n", tmp);

        musb->int_rx = (tmp & DAVINCI_USB_RXINT_MASK)
                        >> DAVINCI_USB_RXINT_SHIFT;
        musb->int_tx = (tmp & DAVINCI_USB_TXINT_MASK)
                        >> DAVINCI_USB_TXINT_SHIFT;
        musb->int_usb = (tmp & DAVINCI_USB_USBINT_MASK)
                        >> DAVINCI_USB_USBINT_SHIFT;

        /* DRVVBUS irqs are the only proxy we have (a very poor one!) for
         * DaVinci'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 we know its
         * value, but DEVCTL.BDEVICE is invalid without DEVCTL.SESSION set.
         * Also, DRVVBUS pulses for SRP (but not at 5V) ...
         */
        if (tmp & (DAVINCI_INTR_DRVVBUS << DAVINCI_USB_USBINT_SHIFT)) {
                int     drvvbus = musb_readl(tibase, DAVINCI_USB_STAT_REG);
                void __iomem *mregs = musb->mregs;
                u8      devctl = musb_readb(mregs, MUSB_DEVCTL);
                int     err = musb->int_usb & MUSB_INTR_VBUSERROR;

                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 (on EVM, a **long** time) 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);
                }

                /* NOTE:  this must complete poweron within 100 msec
                 * (OTG_TIME_A_WAIT_VRISE) but we don't check for that.
                 */
                davinci_musb_source_power(musb, drvvbus, 0);
                dev_dbg(musb->controller, "VBUS %s (%s)%s, devctl %02x\n",
                                drvvbus ? "on" : "off",
                                usb_otg_state_string(musb->xceiv->state),
                                err ? " ERROR" : "",
                                devctl);
                retval = IRQ_HANDLED;
        }

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

        /* irq stays asserted until EOI is written */
        musb_writel(tibase, DAVINCI_USB_EOI_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 retval;
}

static int davinci_musb_set_mode(struct musb *musb, u8 mode)
{
        /* EVM can't do this (right?) */
        return -EIO;
}

static int davinci_musb_init(struct musb *musb)
{
        void __iomem    *tibase = musb->ctrl_base;
        u32             revision;
        int             ret = -ENODEV;

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

        musb->mregs += DAVINCI_BASE_OFFSET;

        /* returns zero if e.g. not clocked */
        revision = musb_readl(tibase, DAVINCI_USB_VERSION_REG);
        if (revision == 0)
                goto fail;

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

        davinci_musb_source_power(musb, 0, 1);

        /* dm355 EVM swaps D+/D- for signal integrity, and
         * is clocked from the main 24 MHz crystal.
         */
        if (machine_is_davinci_dm355_evm()) {
                u32     phy_ctrl = __raw_readl(USB_PHY_CTRL);

                phy_ctrl &= ~(3 << 9);
                phy_ctrl |= USBPHY_DATAPOL;
                __raw_writel(phy_ctrl, USB_PHY_CTRL);
        }

        /* On dm355, the default-A state machine needs DRVVBUS control.
         * If we won't be a host, there's no need to turn it on.
         */
        if (cpu_is_davinci_dm355()) {
                u32     deepsleep = __raw_readl(DM355_DEEPSLEEP);

                deepsleep &= ~DRVVBUS_FORCE;
                __raw_writel(deepsleep, DM355_DEEPSLEEP);
        }

        /* reset the controller */
        musb_writel(tibase, DAVINCI_USB_CTRL_REG, 0x1);

        /* 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("DaVinci OTG revision %08x phy %03x control %02x\n",
                revision, __raw_readl(USB_PHY_CTRL),
                musb_readb(tibase, DAVINCI_USB_CTRL_REG));

        musb->isr = davinci_musb_interrupt;
        return 0;

fail:
        usb_put_phy(musb->xceiv);
unregister:
        usb_nop_xceiv_unregister();
        return ret;
}

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

        /* force VBUS off */
        if (cpu_is_davinci_dm355()) {
                u32     deepsleep = __raw_readl(DM355_DEEPSLEEP);

                deepsleep &= ~DRVVBUS_FORCE;
                deepsleep |= DRVVBUS_OVERRIDE;
                __raw_writel(deepsleep, DM355_DEEPSLEEP);
        }

        davinci_musb_source_power(musb, 0 /*off*/, 1);

        /* delay, to avoid problems with module reload */
        if (musb->xceiv->otg->default_a) {
                int     maxdelay = 30;
                u8      devctl, warn = 0;

                /* if there's no peripheral connected, this can take a
                 * long time to fall, especially on EVM with huge C133.
                 */
                do {
                        devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
                        if (!(devctl & MUSB_DEVCTL_VBUS))
                                break;
                        if ((devctl & MUSB_DEVCTL_VBUS) != warn) {
                                warn = devctl & MUSB_DEVCTL_VBUS;
                                dev_dbg(musb->controller, "VBUS %d\n",
                                        warn >> MUSB_DEVCTL_VBUS_SHIFT);
                        }
                        msleep(1000);
                        maxdelay--;
                } while (maxdelay > 0);

                /* in OTG mode, another host might be connected */
                if (devctl & MUSB_DEVCTL_VBUS)
                        dev_dbg(musb->controller, "VBUS off timeout (devctl %02x)\n", devctl);
        }

        phy_off();

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

        return 0;
}

static const struct musb_platform_ops davinci_ops = {
        .init           = davinci_musb_init,
        .exit           = davinci_musb_exit,

        .enable         = davinci_musb_enable,
        .disable        = davinci_musb_disable,

        .set_mode       = davinci_musb_set_mode,

        .set_vbus       = davinci_musb_set_vbus,
};

static u64 davinci_dmamask = DMA_BIT_MASK(32);

static int davinci_probe(struct platform_device *pdev)
{
        struct musb_hdrc_platform_data  *pdata = pdev->dev.platform_data;
        struct platform_device          *musb;
        struct davinci_glue             *glue;
        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;
        }

        musb = platform_device_alloc("musb-hdrc", PLATFORM_DEVID_AUTO);
        if (!musb) {
                dev_err(&pdev->dev, "failed to allocate musb device\n");
                goto err1;
        }

        clk = clk_get(&pdev->dev, "usb");
        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;
        }

        musb->dev.parent                = &pdev->dev;
        musb->dev.dma_mask              = &davinci_dmamask;
        musb->dev.coherent_dma_mask     = davinci_dmamask;

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

        pdata->platform_ops             = &davinci_ops;

        platform_set_drvdata(pdev, glue);

        ret = platform_device_add_resources(musb, pdev->resource,
                        pdev->num_resources);
        if (ret) {
                dev_err(&pdev->dev, "failed to add resources\n");
                goto err5;
        }

        ret = platform_device_add_data(musb, pdata, sizeof(*pdata));
        if (ret) {
                dev_err(&pdev->dev, "failed to add platform_data\n");
                goto err5;
        }

        ret = platform_device_add(musb);
        if (ret) {
                dev_err(&pdev->dev, "failed to register musb device\n");
                goto err5;
        }

        return 0;

err5:
        clk_disable(clk);

err4:
        clk_put(clk);

err3:
        platform_device_put(musb);

err1:
        kfree(glue);

err0:
        return ret;
}

static int davinci_remove(struct platform_device *pdev)
{
        struct davinci_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 davinci_driver = {
        .probe          = davinci_probe,
        .remove         = davinci_remove,
        .driver         = {
                .name   = "musb-davinci",
        },
};

MODULE_DESCRIPTION("DaVinci MUSB Glue Layer");
MODULE_AUTHOR("Felipe Balbi <balbi@ti.com>");
MODULE_LICENSE("GPL v2");
module_platform_driver(davinci_driver);