/*
 * Texas Instruments DSPS platforms "glue layer"
 *
 * Copyright (C) 2012, by Texas Instruments
 *
 * Based on the am35x "glue layer" code.
 *
 * 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
 *
 * musb_dsps.c will be a common file for all the TI DSPS platforms
 * such as dm64x, dm36x, dm35x, da8x, am35x and ti81x.
 * For now only ti81x is using this and in future davinci.c, am35x.c
 * da8xx.c would be merged to this file after testing.
 */

#include <linux/init.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/pm_runtime.h>
#include <linux/module.h>
#include <linux/usb/usb_phy_gen_xceiv.h>
#include <linux/platform_data/usb-omap.h>
#include <linux/sizes.h>

#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/usb/of.h>

#include "musb_core.h"

static const struct of_device_id musb_dsps_of_match[];

/**
 * avoid using musb_readx()/musb_writex() as glue layer should not be
 * dependent on musb core layer symbols.
 */
static inline u8 dsps_readb(const void __iomem *addr, unsigned offset)
	{ return __raw_readb(addr + offset); }

static inline u32 dsps_readl(const void __iomem *addr, unsigned offset)
	{ return __raw_readl(addr + offset); }

static inline void dsps_writeb(void __iomem *addr, unsigned offset, u8 data)
	{ __raw_writeb(data, addr + offset); }

static inline void dsps_writel(void __iomem *addr, unsigned offset, u32 data)
	{ __raw_writel(data, addr + offset); }

/**
 * DSPS musb wrapper register offset.
 * FIXME: This should be expanded to have all the wrapper registers from TI DSPS
 * musb ips.
 */
struct dsps_musb_wrapper {
	u16	revision;
	u16	control;
	u16	status;
	u16	epintr_set;
	u16	epintr_clear;
	u16	epintr_status;
	u16	coreintr_set;
	u16	coreintr_clear;
	u16	coreintr_status;
	u16	phy_utmi;
	u16	mode;

	/* bit positions for control */
	unsigned	reset:5;

	/* bit positions for interrupt */
	unsigned	usb_shift:5;
	u32		usb_mask;
	u32		usb_bitmap;
	unsigned	drvvbus:5;

	unsigned	txep_shift:5;
	u32		txep_mask;
	u32		txep_bitmap;

	unsigned	rxep_shift:5;
	u32		rxep_mask;
	u32		rxep_bitmap;

	/* bit positions for phy_utmi */
	unsigned	otg_disable:5;

	/* bit positions for mode */
	unsigned	iddig:5;
	/* miscellaneous stuff */
	u8		poll_seconds;
};

/**
 * DSPS glue structure.
 */
struct dsps_glue {
	struct device *dev;
	struct platform_device *musb;	/* child musb pdev */
	const struct dsps_musb_wrapper *wrp; /* wrapper register offsets */
	struct timer_list timer;	/* otg_workaround timer */
	unsigned long last_timer;    /* last timer data for each instance */
};

/**
 * dsps_musb_enable - enable interrupts
 */
static void dsps_musb_enable(struct musb *musb)
{
	struct device *dev = musb->controller;
	struct platform_device *pdev = to_platform_device(dev->parent);
	struct dsps_glue *glue = platform_get_drvdata(pdev);
	const struct dsps_musb_wrapper *wrp = glue->wrp;
	void __iomem *reg_base = musb->ctrl_base;
	u32 epmask, coremask;

	/* Workaround: setup IRQs through both register sets. */
	epmask = ((musb->epmask & wrp->txep_mask) << wrp->txep_shift) |
	       ((musb->epmask & wrp->rxep_mask) << wrp->rxep_shift);
	coremask = (wrp->usb_bitmap & ~MUSB_INTR_SOF);

	dsps_writel(reg_base, wrp->epintr_set, epmask);
	dsps_writel(reg_base, wrp->coreintr_set, coremask);
	/* Force the DRVVBUS IRQ so we can start polling for ID change. */
	dsps_writel(reg_base, wrp->coreintr_set,
		    (1 << wrp->drvvbus) << wrp->usb_shift);
}

/**
 * dsps_musb_disable - disable HDRC and flush interrupts
 */
static void dsps_musb_disable(struct musb *musb)
{
	struct device *dev = musb->controller;
	struct platform_device *pdev = to_platform_device(dev->parent);
	struct dsps_glue *glue = platform_get_drvdata(pdev);
	const struct dsps_musb_wrapper *wrp = glue->wrp;
	void __iomem *reg_base = musb->ctrl_base;

	dsps_writel(reg_base, wrp->coreintr_clear, wrp->usb_bitmap);
	dsps_writel(reg_base, wrp->epintr_clear,
			 wrp->txep_bitmap | wrp->rxep_bitmap);
	dsps_writeb(musb->mregs, MUSB_DEVCTL, 0);
}

static void otg_timer(unsigned long _musb)
{
	struct musb *musb = (void *)_musb;
	void __iomem *mregs = musb->mregs;
	struct device *dev = musb->controller;
	struct dsps_glue *glue = dev_get_drvdata(dev->parent);
	const struct dsps_musb_wrapper *wrp = glue->wrp;
	u8 devctl;
	unsigned long flags;

	/*
	 * We poll because DSPS IP's won't expose several OTG-critical
	 * status change events (from the transceiver) otherwise.
	 */
	devctl = dsps_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;
		dsps_writeb(musb->mregs, MUSB_DEVCTL, devctl);

		devctl = dsps_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;
		dsps_writel(musb->ctrl_base, wrp->coreintr_set,
			    MUSB_INTR_VBUSERROR << wrp->usb_shift);
		break;
	case OTG_STATE_B_IDLE:
		devctl = dsps_readb(mregs, MUSB_DEVCTL);
		if (devctl & MUSB_DEVCTL_BDEVICE)
			mod_timer(&glue->timer,
					jiffies + wrp->poll_seconds * HZ);
		else
			musb->xceiv->state = OTG_STATE_A_IDLE;
		break;
	default:
		break;
	}
	spin_unlock_irqrestore(&musb->lock, flags);
}

static void dsps_musb_try_idle(struct musb *musb, unsigned long timeout)
{
	struct device *dev = musb->controller;
	struct dsps_glue *glue = dev_get_drvdata(dev->parent);

	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(&glue->timer);
		glue->last_timer = jiffies;
		return;
	}

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

static irqreturn_t dsps_interrupt(int irq, void *hci)
{
	struct musb  *musb = hci;
	void __iomem *reg_base = musb->ctrl_base;
	struct device *dev = musb->controller;
	struct dsps_glue *glue = dev_get_drvdata(dev->parent);
	const struct dsps_musb_wrapper *wrp = glue->wrp;
	unsigned long flags;
	irqreturn_t ret = IRQ_NONE;
	u32 epintr, usbintr;

	spin_lock_irqsave(&musb->lock, flags);

	/* Get endpoint interrupts */
	epintr = dsps_readl(reg_base, wrp->epintr_status);
	musb->int_rx = (epintr & wrp->rxep_bitmap) >> wrp->rxep_shift;
	musb->int_tx = (epintr & wrp->txep_bitmap) >> wrp->txep_shift;

	if (epintr)
		dsps_writel(reg_base, wrp->epintr_status, epintr);

	/* Get usb core interrupts */
	usbintr = dsps_readl(reg_base, wrp->coreintr_status);
	if (!usbintr && !epintr)
		goto out;

	musb->int_usb =	(usbintr & wrp->usb_bitmap) >> wrp->usb_shift;
	if (usbintr)
		dsps_writel(reg_base, wrp->coreintr_status, usbintr);

	dev_dbg(musb->controller, "usbintr (%x) epintr(%x)\n",
			usbintr, epintr);
	/*
	 * DRVVBUS IRQs are the only proxy we have (a very poor one!) for
	 * DSPS IP'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 (is_host_active(musb) && usbintr & MUSB_INTR_BABBLE)
		pr_info("CAUTION: musb: Babble Interrupt Occurred\n");

	if (usbintr & ((1 << wrp->drvvbus) << wrp->usb_shift)) {
		int drvvbus = dsps_readl(reg_base, wrp->status);
		void __iomem *mregs = musb->mregs;
		u8 devctl = dsps_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(&glue->timer,
					jiffies + wrp->poll_seconds * HZ);
			WARNING("VBUS error workaround (delay coming)\n");
		} else if (drvvbus) {
			MUSB_HST_MODE(musb);
			musb->xceiv->otg->default_a = 1;
			musb->xceiv->state = OTG_STATE_A_WAIT_VRISE;
			del_timer(&glue->timer);
		} else {
			musb->is_active = 0;
			MUSB_DEV_MODE(musb);
			musb->xceiv->otg->default_a = 0;
			musb->xceiv->state = OTG_STATE_B_IDLE;
		}

		/* 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;
	}

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

	/* Poll for ID change */
	if (musb->xceiv->state == OTG_STATE_B_IDLE)
		mod_timer(&glue->timer, jiffies + wrp->poll_seconds * HZ);
out:
	spin_unlock_irqrestore(&musb->lock, flags);

	return ret;
}

static int dsps_musb_init(struct musb *musb)
{
	struct device *dev = musb->controller;
	struct dsps_glue *glue = dev_get_drvdata(dev->parent);
	struct platform_device *parent = to_platform_device(dev->parent);
	const struct dsps_musb_wrapper *wrp = glue->wrp;
	void __iomem *reg_base;
	struct resource *r;
	u32 rev, val;

	r = platform_get_resource_byname(parent, IORESOURCE_MEM, "control");
	if (!r)
		return -EINVAL;

	reg_base = devm_ioremap_resource(dev, r);
	if (IS_ERR(reg_base))
		return PTR_ERR(reg_base);
	musb->ctrl_base = reg_base;

	/* NOP driver needs change if supporting dual instance */
	musb->xceiv = devm_usb_get_phy_by_phandle(dev, "phys", 0);
	if (IS_ERR(musb->xceiv))
		return PTR_ERR(musb->xceiv);

	/* Returns zero if e.g. not clocked */
	rev = dsps_readl(reg_base, wrp->revision);
	if (!rev)
		return -ENODEV;

	usb_phy_init(musb->xceiv);
	setup_timer(&glue->timer, otg_timer, (unsigned long) musb);

	/* Reset the musb */
	dsps_writel(reg_base, wrp->control, (1 << wrp->reset));

	musb->isr = dsps_interrupt;

	/* reset the otgdisable bit, needed for host mode to work */
	val = dsps_readl(reg_base, wrp->phy_utmi);
	val &= ~(1 << wrp->otg_disable);
	dsps_writel(musb->ctrl_base, wrp->phy_utmi, val);

	return 0;
}

static int dsps_musb_exit(struct musb *musb)
{
	struct device *dev = musb->controller;
	struct dsps_glue *glue = dev_get_drvdata(dev->parent);

	del_timer_sync(&glue->timer);

	usb_phy_shutdown(musb->xceiv);
	return 0;
}

static struct musb_platform_ops dsps_ops = {
	.init		= dsps_musb_init,
	.exit		= dsps_musb_exit,

	.enable		= dsps_musb_enable,
	.disable	= dsps_musb_disable,

	.try_idle	= dsps_musb_try_idle,
};

static u64 musb_dmamask = DMA_BIT_MASK(32);

static int get_int_prop(struct device_node *dn, const char *s)
{
	int ret;
	u32 val;

	ret = of_property_read_u32(dn, s, &val);
	if (ret)
		return 0;
	return val;
}

static int get_musb_port_mode(struct device *dev)
{
	enum usb_dr_mode mode;

	mode = of_usb_get_dr_mode(dev->of_node);
	switch (mode) {
	case USB_DR_MODE_HOST:
		return MUSB_PORT_MODE_HOST;

	case USB_DR_MODE_PERIPHERAL:
		return MUSB_PORT_MODE_GADGET;

	case USB_DR_MODE_UNKNOWN:
	case USB_DR_MODE_OTG:
	default:
		return MUSB_PORT_MODE_DUAL_ROLE;
	};
}

static int dsps_create_musb_pdev(struct dsps_glue *glue,
		struct platform_device *parent)
{
	struct musb_hdrc_platform_data pdata;
	struct resource	resources[2];
	struct resource	*res;
	struct device *dev = &parent->dev;
	struct musb_hdrc_config	*config;
	struct platform_device *musb;
	struct device_node *dn = parent->dev.of_node;
	int ret;

	memset(resources, 0, sizeof(resources));
	res = platform_get_resource_byname(parent, IORESOURCE_MEM, "mc");
	if (!res) {
		dev_err(dev, "failed to get memory.\n");
		return -EINVAL;
	}
	resources[0] = *res;

	res = platform_get_resource_byname(parent, IORESOURCE_IRQ, "mc");
	if (!res) {
		dev_err(dev, "failed to get irq.\n");
		return -EINVAL;
	}
	resources[1] = *res;

	/* allocate the child platform device */
	musb = platform_device_alloc("musb-hdrc", PLATFORM_DEVID_AUTO);
	if (!musb) {
		dev_err(dev, "failed to allocate musb device\n");
		return -ENOMEM;
	}

	musb->dev.parent		= dev;
	musb->dev.dma_mask		= &musb_dmamask;
	musb->dev.coherent_dma_mask	= musb_dmamask;
	musb->dev.of_node		= of_node_get(dn);

	glue->musb = musb;

	ret = platform_device_add_resources(musb, resources,
			ARRAY_SIZE(resources));
	if (ret) {
		dev_err(dev, "failed to add resources\n");
		goto err;
	}

	config = devm_kzalloc(&parent->dev, sizeof(*config), GFP_KERNEL);
	if (!config) {
		dev_err(dev, "failed to allocate musb hdrc config\n");
		ret = -ENOMEM;
		goto err;
	}
	pdata.config = config;
	pdata.platform_ops = &dsps_ops;

	config->num_eps = get_int_prop(dn, "mentor,num-eps");
	config->ram_bits = get_int_prop(dn, "mentor,ram-bits");
	pdata.mode = get_musb_port_mode(dev);
	/* DT keeps this entry in mA, musb expects it as per USB spec */
	pdata.power = get_int_prop(dn, "mentor,power") / 2;
	config->multipoint = of_property_read_bool(dn, "mentor,multipoint");

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

	ret = platform_device_add(musb);
	if (ret) {
		dev_err(dev, "failed to register musb device\n");
		goto err;
	}
	return 0;

err:
	platform_device_put(musb);
	return ret;
}

static int dsps_probe(struct platform_device *pdev)
{
	const struct of_device_id *match;
	const struct dsps_musb_wrapper *wrp;
	struct dsps_glue *glue;
	int ret;

	match = of_match_node(musb_dsps_of_match, pdev->dev.of_node);
	if (!match) {
		dev_err(&pdev->dev, "fail to get matching of_match struct\n");
		return -EINVAL;
	}
	wrp = match->data;

	/* allocate glue */
	glue = kzalloc(sizeof(*glue), GFP_KERNEL);
	if (!glue) {
		dev_err(&pdev->dev, "unable to allocate glue memory\n");
		return -ENOMEM;
	}

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

	platform_set_drvdata(pdev, glue);
	pm_runtime_enable(&pdev->dev);

	ret = pm_runtime_get_sync(&pdev->dev);
	if (ret < 0) {
		dev_err(&pdev->dev, "pm_runtime_get_sync FAILED");
		goto err2;
	}

	ret = dsps_create_musb_pdev(glue, pdev);
	if (ret)
		goto err3;

	return 0;

err3:
	pm_runtime_put(&pdev->dev);
err2:
	pm_runtime_disable(&pdev->dev);
	kfree(glue);
	return ret;
}

static int dsps_remove(struct platform_device *pdev)
{
	struct dsps_glue *glue = platform_get_drvdata(pdev);

	platform_device_unregister(glue->musb);

	/* disable usbss clocks */
	pm_runtime_put(&pdev->dev);
	pm_runtime_disable(&pdev->dev);
	kfree(glue);
	return 0;
}

static const struct dsps_musb_wrapper am33xx_driver_data = {
	.revision		= 0x00,
	.control		= 0x14,
	.status			= 0x18,
	.epintr_set		= 0x38,
	.epintr_clear		= 0x40,
	.epintr_status		= 0x30,
	.coreintr_set		= 0x3c,
	.coreintr_clear		= 0x44,
	.coreintr_status	= 0x34,
	.phy_utmi		= 0xe0,
	.mode			= 0xe8,
	.reset			= 0,
	.otg_disable		= 21,
	.iddig			= 8,
	.usb_shift		= 0,
	.usb_mask		= 0x1ff,
	.usb_bitmap		= (0x1ff << 0),
	.drvvbus		= 8,
	.txep_shift		= 0,
	.txep_mask		= 0xffff,
	.txep_bitmap		= (0xffff << 0),
	.rxep_shift		= 16,
	.rxep_mask		= 0xfffe,
	.rxep_bitmap		= (0xfffe << 16),
	.poll_seconds		= 2,
};

static const struct of_device_id musb_dsps_of_match[] = {
	{ .compatible = "ti,musb-am33xx",
		.data = (void *) &am33xx_driver_data, },
	{  },
};
MODULE_DEVICE_TABLE(of, musb_dsps_of_match);

static struct platform_driver dsps_usbss_driver = {
	.probe		= dsps_probe,
	.remove         = dsps_remove,
	.driver         = {
		.name   = "musb-dsps",
		.of_match_table	= of_match_ptr(musb_dsps_of_match),
	},
};

MODULE_DESCRIPTION("TI DSPS MUSB Glue Layer");
MODULE_AUTHOR("Ravi B <ravibabu@ti.com>");
MODULE_AUTHOR("Ajay Kumar Gupta <ajay.gupta@ti.com>");
MODULE_LICENSE("GPL v2");

module_platform_driver(dsps_usbss_driver);