/*
 * Texas Instruments AM35x "glue layer"
 *
 * Copyright (c) 2010, by Texas Instruments
 *
 * Based on the DA8xx "glue layer" code.
 * Copyright (c) 2008-2009, MontaVista Software, Inc. <source@mvista.com>
 *
 * 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/init.h>
#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 <linux/platform_data/usb-omap.h>

#include "musb_core.h"

/*
 * AM35x specific definitions
 */
/* USB 2.0 OTG module registers */
#define USB_REVISION_REG        0x00
#define USB_CTRL_REG            0x04
#define USB_STAT_REG            0x08
#define USB_EMULATION_REG       0x0c
/* 0x10 Reserved */
#define USB_AUTOREQ_REG         0x14
#define USB_SRP_FIX_TIME_REG    0x18
#define USB_TEARDOWN_REG        0x1c
#define EP_INTR_SRC_REG         0x20
#define EP_INTR_SRC_SET_REG     0x24
#define EP_INTR_SRC_CLEAR_REG   0x28
#define EP_INTR_MASK_REG        0x2c
#define EP_INTR_MASK_SET_REG    0x30
#define EP_INTR_MASK_CLEAR_REG  0x34
#define EP_INTR_SRC_MASKED_REG  0x38
#define CORE_INTR_SRC_REG       0x40
#define CORE_INTR_SRC_SET_REG   0x44
#define CORE_INTR_SRC_CLEAR_REG 0x48
#define CORE_INTR_MASK_REG      0x4c
#define CORE_INTR_MASK_SET_REG  0x50
#define CORE_INTR_MASK_CLEAR_REG 0x54
#define CORE_INTR_SRC_MASKED_REG 0x58
/* 0x5c Reserved */
#define USB_END_OF_INTR_REG     0x60

/* Control register bits */
#define AM35X_SOFT_RESET_MASK   1

/* USB interrupt register bits */
#define AM35X_INTR_USB_SHIFT    16
#define AM35X_INTR_USB_MASK     (0x1ff << AM35X_INTR_USB_SHIFT)
#define AM35X_INTR_DRVVBUS      0x100
#define AM35X_INTR_RX_SHIFT     16
#define AM35X_INTR_TX_SHIFT     0
#define AM35X_TX_EP_MASK        0xffff          /* EP0 + 15 Tx EPs */
#define AM35X_RX_EP_MASK        0xfffe          /* 15 Rx EPs */
#define AM35X_TX_INTR_MASK      (AM35X_TX_EP_MASK << AM35X_INTR_TX_SHIFT)
#define AM35X_RX_INTR_MASK      (AM35X_RX_EP_MASK << AM35X_INTR_RX_SHIFT)

#define USB_MENTOR_CORE_OFFSET  0x400

struct am35x_glue {
        struct device           *dev;
        struct platform_device  *musb;
        struct clk              *phy_clk;
        struct clk              *clk;
};
#define glue_to_musb(g)         platform_get_drvdata(g->musb)

/*
 * am35x_musb_enable - enable interrupts
 */
static void am35x_musb_enable(struct musb *musb)
{
        void __iomem *reg_base = musb->ctrl_base;
        u32 epmask;

        /* Workaround: setup IRQs through both register sets. */
        epmask = ((musb->epmask & AM35X_TX_EP_MASK) << AM35X_INTR_TX_SHIFT) |
               ((musb->epmask & AM35X_RX_EP_MASK) << AM35X_INTR_RX_SHIFT);

        musb_writel(reg_base, EP_INTR_MASK_SET_REG, epmask);
        musb_writel(reg_base, CORE_INTR_MASK_SET_REG, AM35X_INTR_USB_MASK);

        /* Force the DRVVBUS IRQ so we can start polling for ID change. */
        musb_writel(reg_base, CORE_INTR_SRC_SET_REG,
                        AM35X_INTR_DRVVBUS << AM35X_INTR_USB_SHIFT);
}

/*
 * am35x_musb_disable - disable HDRC and flush interrupts
 */
static void am35x_musb_disable(struct musb *musb)
{
        void __iomem *reg_base = musb->ctrl_base;

        musb_writel(reg_base, CORE_INTR_MASK_CLEAR_REG, AM35X_INTR_USB_MASK);
        musb_writel(reg_base, EP_INTR_MASK_CLEAR_REG,
                         AM35X_TX_INTR_MASK | AM35X_RX_INTR_MASK);
        musb_writeb(musb->mregs, MUSB_DEVCTL, 0);
        musb_writel(reg_base, USB_END_OF_INTR_REG, 0);
}

#define portstate(stmt)         stmt

static void am35x_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 AM35x'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:
                musb->xceiv->state = OTG_STATE_A_WAIT_VRISE;
                musb_writel(musb->ctrl_base, CORE_INTR_SRC_SET_REG,
                            MUSB_INTR_VBUSERROR << AM35X_INTR_USB_SHIFT);
                break;
        case OTG_STATE_B_IDLE:
                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 am35x_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 am35x_musb_interrupt(int irq, void *hci)
{
        struct musb  *musb = hci;
        void __iomem *reg_base = musb->ctrl_base;
        struct device *dev = musb->controller;
        struct musb_hdrc_platform_data *plat = dev_get_platdata(dev);
        struct omap_musb_board_data *data = plat->board_data;
        struct usb_otg *otg = musb->xceiv->otg;
        unsigned long flags;
        irqreturn_t ret = IRQ_NONE;
        u32 epintr, usbintr;

        spin_lock_irqsave(&musb->lock, flags);

        /* Get endpoint interrupts */
        epintr = musb_readl(reg_base, EP_INTR_SRC_MASKED_REG);

        if (epintr) {
                musb_writel(reg_base, EP_INTR_SRC_CLEAR_REG, epintr);

                musb->int_rx =
                        (epintr & AM35X_RX_INTR_MASK) >> AM35X_INTR_RX_SHIFT;
                musb->int_tx =
                        (epintr & AM35X_TX_INTR_MASK) >> AM35X_INTR_TX_SHIFT;
        }

        /* Get usb core interrupts */
        usbintr = musb_readl(reg_base, CORE_INTR_SRC_MASKED_REG);
        if (!usbintr && !epintr)
                goto eoi;

        if (usbintr) {
                musb_writel(reg_base, CORE_INTR_SRC_CLEAR_REG, usbintr);

                musb->int_usb =
                        (usbintr & AM35X_INTR_USB_MASK) >> AM35X_INTR_USB_SHIFT;
        }
        /*
         * DRVVBUS IRQs are the only proxy we have (a very poor one!) for
         * AM35x'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 5V) ...
         */
        if (usbintr & (AM35X_INTR_DRVVBUS << AM35X_INTR_USB_SHIFT)) {
                int drvvbus = musb_readl(reg_base, 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);
                }

                /* NOTE: this must complete power-on within 100 ms. */
                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;
        }

        /* Drop spurious RX and TX if device is disconnected */
        if (musb->int_usb & MUSB_INTR_DISCONNECT) {
                musb->int_tx = 0;
                musb->int_rx = 0;
        }

        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 || epintr || usbintr) {
                /* clear level interrupt */
                if (data->clear_irq)
                        data->clear_irq();
                /* write EOI */
                musb_writel(reg_base, 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 am35x_musb_set_mode(struct musb *musb, u8 musb_mode)
{
        struct device *dev = musb->controller;
        struct musb_hdrc_platform_data *plat = dev_get_platdata(dev);
        struct omap_musb_board_data *data = plat->board_data;
        int     retval = 0;

        if (data->set_mode)
                data->set_mode(musb_mode);
        else
                retval = -EIO;

        return retval;
}

static int am35x_musb_init(struct musb *musb)
{
        struct device *dev = musb->controller;
        struct musb_hdrc_platform_data *plat = dev_get_platdata(dev);
        struct omap_musb_board_data *data = plat->board_data;
        void __iomem *reg_base = musb->ctrl_base;
        u32 rev;

        musb->mregs += USB_MENTOR_CORE_OFFSET;

        /* Returns zero if e.g. not clocked */
        rev = musb_readl(reg_base, USB_REVISION_REG);
        if (!rev)
                return -ENODEV;

        usb_nop_xceiv_register();
        musb->xceiv = usb_get_phy(USB_PHY_TYPE_USB2);
        if (IS_ERR_OR_NULL(musb->xceiv))
                return -EPROBE_DEFER;

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

        /* Reset the musb */
        if (data->reset)
                data->reset();

        /* Reset the controller */
        musb_writel(reg_base, USB_CTRL_REG, AM35X_SOFT_RESET_MASK);

        /* Start the on-chip PHY and its PLL. */
        if (data->set_phy_power)
                data->set_phy_power(1);

        msleep(5);

        musb->isr = am35x_musb_interrupt;

        /* clear level interrupt */
        if (data->clear_irq)
                data->clear_irq();

        return 0;
}

static int am35x_musb_exit(struct musb *musb)
{
        struct device *dev = musb->controller;
        struct musb_hdrc_platform_data *plat = dev_get_platdata(dev);
        struct omap_musb_board_data *data = plat->board_data;

        del_timer_sync(&otg_workaround);

        /* Shutdown the on-chip PHY and its PLL. */
        if (data->set_phy_power)
                data->set_phy_power(0);

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

        return 0;
}

/* AM35x supports only 32bit read operation */
void musb_read_fifo(struct musb_hw_ep *hw_ep, u16 len, u8 *dst)
{
        void __iomem *fifo = hw_ep->fifo;
        u32             val;
        int             i;

        /* Read for 32bit-aligned destination address */
        if (likely((0x03 & (unsigned long) dst) == 0) && len >= 4) {
                readsl(fifo, dst, len >> 2);
                dst += len & ~0x03;
                len &= 0x03;
        }
        /*
         * Now read the remaining 1 to 3 byte or complete length if
         * unaligned address.
         */
        if (len > 4) {
                for (i = 0; i < (len >> 2); i++) {
                        *(u32 *) dst = musb_readl(fifo, 0);
                        dst += 4;
                }
                len &= 0x03;
        }
        if (len > 0) {
                val = musb_readl(fifo, 0);
                memcpy(dst, &val, len);
        }
}

static const struct musb_platform_ops am35x_ops = {
        .init           = am35x_musb_init,
        .exit           = am35x_musb_exit,

        .enable         = am35x_musb_enable,
        .disable        = am35x_musb_disable,

        .set_mode       = am35x_musb_set_mode,
        .try_idle       = am35x_musb_try_idle,

        .set_vbus       = am35x_musb_set_vbus,
};

static u64 am35x_dmamask = DMA_BIT_MASK(32);

static int am35x_probe(struct platform_device *pdev)
{
        struct musb_hdrc_platform_data  *pdata = dev_get_platdata(&pdev->dev);
        struct platform_device          *musb;
        struct am35x_glue               *glue;

        struct clk                      *phy_clk;
        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;
        }

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

        clk = clk_get(&pdev->dev, "ick");
        if (IS_ERR(clk)) {
                dev_err(&pdev->dev, "failed to get clock\n");
                ret = PTR_ERR(clk);
                goto err4;
        }

        ret = clk_enable(phy_clk);
        if (ret) {
                dev_err(&pdev->dev, "failed to enable PHY clock\n");
                goto err5;
        }

        ret = clk_enable(clk);
        if (ret) {
                dev_err(&pdev->dev, "failed to enable clock\n");
                goto err6;
        }

        musb->dev.parent                = &pdev->dev;
        musb->dev.dma_mask              = &am35x_dmamask;
        musb->dev.coherent_dma_mask     = am35x_dmamask;

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

        pdata->platform_ops             = &am35x_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 err7;
        }

        ret = platform_device_add_data(musb, pdata, sizeof(*pdata));
        if (ret) {
                dev_err(&pdev->dev, "failed to add platform_data\n");
                goto err7;
        }

        ret = platform_device_add(musb);
        if (ret) {
                dev_err(&pdev->dev, "failed to register musb device\n");
                goto err7;
        }

        return 0;

err7:
        clk_disable(clk);

err6:
        clk_disable(phy_clk);

err5:
        clk_put(clk);

err4:
        clk_put(phy_clk);

err3:
        platform_device_put(musb);

err1:
        kfree(glue);

err0:
        return ret;
}

static int am35x_remove(struct platform_device *pdev)
{
        struct am35x_glue       *glue = platform_get_drvdata(pdev);

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

        return 0;
}

#ifdef CONFIG_PM
static int am35x_suspend(struct device *dev)
{
        struct am35x_glue       *glue = dev_get_drvdata(dev);
        struct musb_hdrc_platform_data *plat = dev_get_platdata(dev);
        struct omap_musb_board_data *data = plat->board_data;

        /* Shutdown the on-chip PHY and its PLL. */
        if (data->set_phy_power)
                data->set_phy_power(0);

        clk_disable(glue->phy_clk);
        clk_disable(glue->clk);

        return 0;
}

static int am35x_resume(struct device *dev)
{
        struct am35x_glue       *glue = dev_get_drvdata(dev);
        struct musb_hdrc_platform_data *plat = dev_get_platdata(dev);
        struct omap_musb_board_data *data = plat->board_data;
        int                     ret;

        /* Start the on-chip PHY and its PLL. */
        if (data->set_phy_power)
                data->set_phy_power(1);

        ret = clk_enable(glue->phy_clk);
        if (ret) {
                dev_err(dev, "failed to enable PHY clock\n");
                return ret;
        }

        ret = clk_enable(glue->clk);
        if (ret) {
                dev_err(dev, "failed to enable clock\n");
                return ret;
        }

        return 0;
}

static struct dev_pm_ops am35x_pm_ops = {
        .suspend        = am35x_suspend,
        .resume         = am35x_resume,
};

#define DEV_PM_OPS      &am35x_pm_ops
#else
#define DEV_PM_OPS      NULL
#endif

static struct platform_driver am35x_driver = {
        .probe          = am35x_probe,
        .remove         = am35x_remove,
        .driver         = {
                .name   = "musb-am35x",
                .pm     = DEV_PM_OPS,
        },
};

MODULE_DESCRIPTION("AM35x MUSB Glue Layer");
MODULE_AUTHOR("Ajay Kumar Gupta <ajay.gupta@ti.com>");
MODULE_LICENSE("GPL v2");
module_platform_driver(am35x_driver);