// SPDX-License-Identifier: GPL-2.0
/*
 * 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
 *
 * DT support
 * Copyright (c) 2016 Petr Kulhavy <petr@barix.com>
 *
 * This file is part of the Inventra Controller Driver for Linux.
 */

#include <linux/module.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/of_platform.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/usb/usb_phy_generic.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_SRP_FIX_TIME_REG 0x18
#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

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

/*
 * 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_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 void otg_timer(struct timer_list *t)
{
        struct musb             *musb = from_timer(musb, t, dev_timer);
        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->otg->state));

        spin_lock_irqsave(&musb->lock, flags);
        switch (musb->xceiv->otg->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->otg->state = OTG_STATE_B_IDLE;
                        MUSB_DEV_MODE(musb);
                } else {
                        musb->xceiv->otg->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(&musb->dev_timer, jiffies + POLL_SECONDS * HZ);
                        break;
                }
                musb->xceiv->otg->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(&musb->dev_timer, jiffies + POLL_SECONDS * HZ);
                else
                        musb->xceiv->otg->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->otg->state == OTG_STATE_A_WAIT_BCON)) {
                dev_dbg(musb->controller, "%s active, deleting timer\n",
                        usb_otg_state_string(musb->xceiv->otg->state));
                del_timer(&musb->dev_timer);
                last_timer = jiffies;
                return;
        }

        if (time_after(last_timer, timeout) && timer_pending(&musb->dev_timer)) {
                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->otg->state),
                jiffies_to_msecs(timeout - jiffies));
        mod_timer(&musb->dev_timer, timeout);
}

static irqreturn_t da8xx_musb_interrupt(int irq, void *hci)
{
        struct musb             *musb = hci;
        void __iomem            *reg_base = musb->ctrl_base;
        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->otg->state = OTG_STATE_A_WAIT_VFALL;
                        mod_timer(&musb->dev_timer, jiffies + POLL_SECONDS * HZ);
                        WARNING("VBUS error workaround (delay coming)\n");
                } else if (drvvbus) {
                        MUSB_HST_MODE(musb);
                        musb->xceiv->otg->state = OTG_STATE_A_WAIT_VRISE;
                        portstate(musb->port1_status |= USB_PORT_STAT_POWER);
                        del_timer(&musb->dev_timer);
                } else if (!(musb->int_usb & MUSB_INTR_BABBLE)) {
                        /*
                         * When babble condition happens, drvvbus interrupt
                         * is also generated. Ignore this drvvbus interrupt
                         * and let babble interrupt handler recovers the
                         * controller; otherwise, the host-mode flag is lost
                         * due to the MUSB_DEV_MODE() call below and babble
                         * recovery logic will not be called.
                         */
                        musb->is_active = 0;
                        MUSB_DEV_MODE(musb);
                        musb->xceiv->otg->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->otg->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->otg->state == OTG_STATE_B_IDLE)
                mod_timer(&musb->dev_timer, jiffies + POLL_SECONDS * HZ);

        spin_unlock_irqrestore(&musb->lock, flags);

        return ret;
}

static int da8xx_musb_set_mode(struct musb *musb, u8 musb_mode)
{
        struct da8xx_glue *glue = dev_get_drvdata(musb->controller->parent);
        enum phy_mode phy_mode;

        /*
         * The PHY has some issues when it is forced in device or host mode.
         * Unless the user request another mode, configure the PHY in OTG mode.
         */
        if (!musb->is_initialized)
                return phy_set_mode(glue->phy, PHY_MODE_USB_OTG);

        switch (musb_mode) {
        case MUSB_HOST:         /* Force VBUS valid, ID = 0 */
                phy_mode = PHY_MODE_USB_HOST;
                break;
        case MUSB_PERIPHERAL:   /* Force VBUS valid, ID = 1 */
                phy_mode = PHY_MODE_USB_DEVICE;
                break;
        case MUSB_OTG:          /* Don't override the VBUS/ID comparators */
                phy_mode = PHY_MODE_USB_OTG;
                break;
        default:
                return -EINVAL;
        }

        return phy_set_mode(glue->phy, phy_mode);
}

static int da8xx_musb_init(struct musb *musb)
{
        struct da8xx_glue *glue = dev_get_drvdata(musb->controller->parent);
        void __iomem *reg_base = musb->ctrl_base;
        u32 rev;
        int ret = -ENODEV;

        musb->mregs += DA8XX_MENTOR_CORE_OFFSET;

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

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

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

        timer_setup(&musb->dev_timer, otg_timer, 0);

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

        /* Start the on-chip PHY and its PLL. */
        ret = phy_init(glue->phy);
        if (ret) {
                dev_err(glue->dev, "Failed to init phy.\n");
                goto fail;
        }

        ret = phy_power_on(glue->phy);
        if (ret) {
                dev_err(glue->dev, "Failed to power on phy.\n");
                goto err_phy_power_on;
        }

        msleep(5);

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

        musb->isr = da8xx_musb_interrupt;
        return 0;

err_phy_power_on:
        phy_exit(glue->phy);
fail:
        clk_disable_unprepare(glue->clk);
        return ret;
}

static int da8xx_musb_exit(struct musb *musb)
{
        struct da8xx_glue *glue = dev_get_drvdata(musb->controller->parent);

        del_timer_sync(&musb->dev_timer);

        phy_power_off(glue->phy);
        phy_exit(glue->phy);
        clk_disable_unprepare(glue->clk);

        usb_put_phy(musb->xceiv);

        return 0;
}

static inline u8 get_vbus_power(struct device *dev)
{
        struct regulator *vbus_supply;
        int current_uA;

        vbus_supply = regulator_get_optional(dev, "vbus");
        if (IS_ERR(vbus_supply))
                return 255;
        current_uA = regulator_get_current_limit(vbus_supply);
        regulator_put(vbus_supply);
        if (current_uA <= 0 || current_uA > 510000)
                return 255;
        return current_uA / 1000 / 2;
}

#ifdef CONFIG_USB_TI_CPPI41_DMA
static void da8xx_dma_controller_callback(struct dma_controller *c)
{
        struct musb *musb = c->musb;
        void __iomem *reg_base = musb->ctrl_base;

        musb_writel(reg_base, DA8XX_USB_END_OF_INTR_REG, 0);
}

static struct dma_controller *
da8xx_dma_controller_create(struct musb *musb, void __iomem *base)
{
        struct dma_controller *controller;

        controller = cppi41_dma_controller_create(musb, base);
        if (IS_ERR_OR_NULL(controller))
                return controller;

        controller->dma_callback = da8xx_dma_controller_callback;

        return controller;
}
#endif

static const struct musb_platform_ops da8xx_ops = {
        .quirks         = MUSB_INDEXED_EP | MUSB_PRESERVE_SESSION |
                          MUSB_DMA_CPPI41 | MUSB_DA8XX,
        .init           = da8xx_musb_init,
        .exit           = da8xx_musb_exit,

        .fifo_mode      = 2,
#ifdef CONFIG_USB_TI_CPPI41_DMA
        .dma_init       = da8xx_dma_controller_create,
        .dma_exit       = cppi41_dma_controller_destroy,
#endif
        .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 const struct musb_hdrc_config da8xx_config = {
        .ram_bits = 10,
        .num_eps = 5,
        .multipoint = 1,
};

static struct of_dev_auxdata da8xx_auxdata_lookup[] = {
        OF_DEV_AUXDATA("ti,da830-cppi41", 0x01e01000, "cppi41-dmaengine",
                       NULL),
        {}
};

static int da8xx_probe(struct platform_device *pdev)
{
        struct musb_hdrc_platform_data  *pdata = dev_get_platdata(&pdev->dev);
        struct da8xx_glue               *glue;
        struct platform_device_info     pinfo;
        struct clk                      *clk;
        struct device_node              *np = pdev->dev.of_node;
        int                             ret;

        glue = devm_kzalloc(&pdev->dev, sizeof(*glue), GFP_KERNEL);
        if (!glue)
                return -ENOMEM;

        clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(clk)) {
                dev_err(&pdev->dev, "failed to get clock\n");
                return PTR_ERR(clk);
        }

        glue->phy = devm_phy_get(&pdev->dev, "usb-phy");
        if (IS_ERR(glue->phy)) {
                if (PTR_ERR(glue->phy) != -EPROBE_DEFER)
                        dev_err(&pdev->dev, "failed to get phy\n");
                return PTR_ERR(glue->phy);
        }

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

        if (IS_ENABLED(CONFIG_OF) && np) {
                pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
                if (!pdata)
                        return -ENOMEM;

                pdata->config   = &da8xx_config;
                pdata->mode     = musb_get_mode(&pdev->dev);
                pdata->power    = get_vbus_power(&pdev->dev);
        }

        pdata->platform_ops             = &da8xx_ops;

        glue->usb_phy = usb_phy_generic_register();
        ret = PTR_ERR_OR_ZERO(glue->usb_phy);
        if (ret) {
                dev_err(&pdev->dev, "failed to register usb_phy\n");
                return ret;
        }
        platform_set_drvdata(pdev, glue);

        ret = of_platform_populate(pdev->dev.of_node, NULL,
                                   da8xx_auxdata_lookup, &pdev->dev);
        if (ret)
                return ret;

        pinfo = da8xx_dev_info;
        pinfo.parent = &pdev->dev;
        pinfo.res = pdev->resource;
        pinfo.num_res = pdev->num_resources;
        pinfo.data = pdata;
        pinfo.size_data = sizeof(*pdata);
        pinfo.fwnode = of_fwnode_handle(np);
        pinfo.of_node_reused = true;

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

        return ret;
}

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

        platform_device_unregister(glue->musb);
        usb_phy_generic_unregister(glue->usb_phy);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int da8xx_suspend(struct device *dev)
{
        int ret;
        struct da8xx_glue *glue = dev_get_drvdata(dev);

        ret = phy_power_off(glue->phy);
        if (ret)
                return ret;
        clk_disable_unprepare(glue->clk);

        return 0;
}

static int da8xx_resume(struct device *dev)
{
        int ret;
        struct da8xx_glue *glue = dev_get_drvdata(dev);

        ret = clk_prepare_enable(glue->clk);
        if (ret)
                return ret;
        return phy_power_on(glue->phy);
}
#endif

static SIMPLE_DEV_PM_OPS(da8xx_pm_ops, da8xx_suspend, da8xx_resume);

#ifdef CONFIG_OF
static const struct of_device_id da8xx_id_table[] = {
        {
                .compatible = "ti,da830-musb",
        },
        {},
};
MODULE_DEVICE_TABLE(of, da8xx_id_table);
#endif

static struct platform_driver da8xx_driver = {
        .probe          = da8xx_probe,
        .remove         = da8xx_remove,
        .driver         = {
                .name   = "musb-da8xx",
                .pm = &da8xx_pm_ops,
                .of_match_table = of_match_ptr(da8xx_id_table),
        },
};

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);