USB: musb: add musb support for AM35x

AM35x has musb interface and uses CPPI4.1 DMA engine.
Current patch supports only PIO mode. DMA support can be
added later once basic CPPI4.1 DMA patch is accepted.

Also added USB_MUSB_AM35X which is required to differentiate musb ips
between OMAP3x and AM35x. This config would be used to for below
purposes,
        - Select am35x.c instead of omap2430.c for compilation
          at drivers/usb/musb directory. Please note there are
          significant differneces in these two files as musb ip
          in quite different on AM35x.

	  Please note that in multi omap configuration only omap2430.c
	  file will get compiled and we would require to select only
	  AM35x based board config to compile am35x.c

        - Select workaround codes applicable for AM35x musb issues.
          one such workaround is for bytewise read issue on AM35x.

Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 494 insertions, 0 deletions

diff --git a/drivers/usb/musb/am35x.c b/drivers/usb/musb/am35x.c
new file mode 100644
index 000000000000..53962a0389eb
--- /dev/null
+++ b/drivers/usb/musb/am35x.c
@@ -0,0 +1,494 @@
+/*
+ * 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/clk.h>
+#include <linux/io.h>
+
+#include <plat/control.h>
+#include <plat/usb.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
+
+static inline void phy_on(void)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(100);
+	u32 devconf2;
+
+	/*
+	 * Start the on-chip PHY and its PLL.
+	 */
+	devconf2 = omap_ctrl_readl(AM35XX_CONTROL_DEVCONF2);
+
+	devconf2 &= ~(CONF2_RESET | CONF2_PHYPWRDN | CONF2_OTGPWRDN);
+	devconf2 |= CONF2_PHY_PLLON;
+
+	omap_ctrl_writel(devconf2, AM35XX_CONTROL_DEVCONF2);
+
+	DBG(1, "Waiting for PHY clock good...\n");
+	while (!(omap_ctrl_readl(AM35XX_CONTROL_DEVCONF2)
+			& CONF2_PHYCLKGD)) {
+		cpu_relax();
+
+		if (time_after(jiffies, timeout)) {
+			DBG(1, "musb PHY clock good timed out\n");
+			break;
+		}
+	}
+}
+
+static inline void phy_off(void)
+{
+	u32 devconf2;
+
+	/*
+	 * Power down the on-chip PHY.
+	 */
+	devconf2 = omap_ctrl_readl(AM35XX_CONTROL_DEVCONF2);
+
+	devconf2 &= ~CONF2_PHY_PLLON;
+	devconf2 |=  CONF2_PHYPWRDN | CONF2_OTGPWRDN;
+	omap_ctrl_writel(devconf2, AM35XX_CONTROL_DEVCONF2);
+}
+
+/*
+ * musb_platform_enable - enable interrupts
+ */
+void musb_platform_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. */
+	if (is_otg_enabled(musb))
+		musb_writel(reg_base, CORE_INTR_SRC_SET_REG,
+			    AM35X_INTR_DRVVBUS << AM35X_INTR_USB_SHIFT);
+}
+
+/*
+ * musb_platform_disable - disable HDRC and flush interrupts
+ */
+void musb_platform_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);
+}
+
+#ifdef CONFIG_USB_MUSB_HDRC_HCD
+#define portstate(stmt)		stmt
+#else
+#define portstate(stmt)
+#endif
+
+static void am35x_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);
+	DBG(7, "Poll devctl %02x (%s)\n", devctl, otg_state_string(musb));
+
+	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:
+		if (!is_peripheral_enabled(musb))
+			break;
+
+		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);
+}
+
+void musb_platform_try_idle(struct musb *musb, unsigned long timeout)
+{
+	static unsigned long last_timer;
+
+	if (!is_otg_enabled(musb))
+		return;
+
+	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)) {
+		DBG(4, "%s active, deleting timer\n", otg_state_string(musb));
+		del_timer(&otg_workaround);
+		last_timer = jiffies;
+		return;
+	}
+
+	if (time_after(last_timer, timeout) && timer_pending(&otg_workaround)) {
+		DBG(4, "Longer idle timer already pending, ignoring...\n");
+		return;
+	}
+	last_timer = timeout;
+
+	DBG(4, "%s inactive, starting idle timer for %u ms\n",
+	    otg_state_string(musb), jiffies_to_msecs(timeout - jiffies));
+	mod_timer(&otg_workaround, timeout);
+}
+
+static irqreturn_t am35x_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 epintr, usbintr, lvl_intr;
+
+	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 = is_host_enabled(musb) && (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 (is_host_enabled(musb) && drvvbus) {
+			MUSB_HST_MODE(musb);
+			musb->xceiv->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);
+			musb->xceiv->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. */
+		DBG(2, "VBUS %s (%s)%s, devctl %02x\n",
+				drvvbus ? "on" : "off",
+				otg_state_string(musb),
+				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 || epintr || usbintr) {
+		/* clear level interrupt */
+		lvl_intr = omap_ctrl_readl(AM35XX_CONTROL_LVL_INTR_CLEAR);
+		lvl_intr |= AM35XX_USBOTGSS_INT_CLR;
+		omap_ctrl_writel(lvl_intr, AM35XX_CONTROL_LVL_INTR_CLEAR);
+		/* write EOI */
+		musb_writel(reg_base, USB_END_OF_INTR_REG, 0);
+	}
+
+	/* Poll for ID change */
+	if (is_otg_enabled(musb) && musb->xceiv->state == OTG_STATE_B_IDLE)
+		mod_timer(&otg_workaround, jiffies + POLL_SECONDS * HZ);
+
+	spin_unlock_irqrestore(&musb->lock, flags);
+
+	return ret;
+}
+
+int musb_platform_set_mode(struct musb *musb, u8 musb_mode)
+{
+	u32 devconf2 = omap_ctrl_readl(AM35XX_CONTROL_DEVCONF2);
+
+	devconf2 &= ~CONF2_OTGMODE;
+	switch (musb_mode) {
+#ifdef	CONFIG_USB_MUSB_HDRC_HCD
+	case MUSB_HOST:		/* Force VBUS valid, ID = 0 */
+		devconf2 |= CONF2_FORCE_HOST;
+		break;
+#endif
+#ifdef	CONFIG_USB_GADGET_MUSB_HDRC
+	case MUSB_PERIPHERAL:	/* Force VBUS valid, ID = 1 */
+		devconf2 |= CONF2_FORCE_DEVICE;
+		break;
+#endif
+#ifdef	CONFIG_USB_MUSB_OTG
+	case MUSB_OTG:		/* Don't override the VBUS/ID comparators */
+		devconf2 |= CONF2_NO_OVERRIDE;
+		break;
+#endif
+	default:
+		DBG(2, "Trying to set unsupported mode %u\n", musb_mode);
+	}
+
+	omap_ctrl_writel(devconf2, AM35XX_CONTROL_DEVCONF2);
+	return 0;
+}
+
+int __init musb_platform_init(struct musb *musb, void *board_data)
+{
+	void __iomem *reg_base = musb->ctrl_base;
+	u32 rev, lvl_intr, sw_reset;
+	int status;
+
+	musb->mregs += USB_MENTOR_CORE_OFFSET;
+
+	clk_enable(musb->clock);
+	DBG(2, "musb->clock=%lud\n", clk_get_rate(musb->clock));
+
+	musb->phy_clock = clk_get(musb->controller, "fck");
+	if (IS_ERR(musb->phy_clock)) {
+		status = PTR_ERR(musb->phy_clock);
+		goto exit0;
+	}
+	clk_enable(musb->phy_clock);
+	DBG(2, "musb->phy_clock=%lud\n", clk_get_rate(musb->phy_clock));
+
+	/* Returns zero if e.g. not clocked */
+	rev = musb_readl(reg_base, USB_REVISION_REG);
+	if (!rev) {
+		status = -ENODEV;
+		goto exit1;
+	}
+
+	usb_nop_xceiv_register();
+	musb->xceiv = otg_get_transceiver();
+	if (!musb->xceiv) {
+		status = -ENODEV;
+		goto exit1;
+	}
+
+	if (is_host_enabled(musb))
+		setup_timer(&otg_workaround, otg_timer, (unsigned long) musb);
+
+	musb->board_set_vbus = am35x_set_vbus;
+
+	/* Global reset */
+	sw_reset = omap_ctrl_readl(AM35XX_CONTROL_IP_SW_RESET);
+
+	sw_reset |= AM35XX_USBOTGSS_SW_RST;
+	omap_ctrl_writel(sw_reset, AM35XX_CONTROL_IP_SW_RESET);
+
+	sw_reset &= ~AM35XX_USBOTGSS_SW_RST;
+	omap_ctrl_writel(sw_reset, AM35XX_CONTROL_IP_SW_RESET);
+
+	/* Reset the controller */
+	musb_writel(reg_base, USB_CTRL_REG, AM35X_SOFT_RESET_MASK);
+
+	/* Start the on-chip PHY and its PLL. */
+	phy_on();
+
+	msleep(5);
+
+	musb->isr = am35x_interrupt;
+
+	/* clear level interrupt */
+	lvl_intr = omap_ctrl_readl(AM35XX_CONTROL_LVL_INTR_CLEAR);
+	lvl_intr |= AM35XX_USBOTGSS_INT_CLR;
+	omap_ctrl_writel(lvl_intr, AM35XX_CONTROL_LVL_INTR_CLEAR);
+	return 0;
+exit1:
+	clk_disable(musb->phy_clock);
+	clk_put(musb->phy_clock);
+exit0:
+	clk_disable(musb->clock);
+	return status;
+}
+
+int musb_platform_exit(struct musb *musb)
+{
+	if (is_host_enabled(musb))
+		del_timer_sync(&otg_workaround);
+
+	phy_off();
+
+	otg_put_transceiver(musb->xceiv);
+	usb_nop_xceiv_unregister();
+
+	clk_disable(musb->clock);
+
+	clk_disable(musb->phy_clock);
+	clk_put(musb->phy_clock);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+void musb_platform_save_context(struct musb *musb,
+	struct musb_context_registers *musb_context)
+{
+	phy_off();
+}
+
+void musb_platform_restore_context(struct musb *musb,
+	struct musb_context_registers *musb_context)
+{
+	phy_on();
+}
+#endif