Fix OMAP EHCI suspend/resume failure (i693)

Its observed with some PHY, the 60Mhz clock gets
cut too soon for OMAP EHCI, leaving OMAP-EHCI in a bad state.

So on starting port suspend, make sure the 60Mhz clock to EHCI
is kept alive using an internal clock, so that EHCi can cleanly
transition its hw state machine on a port suspend.

Its not proven if this is the issue hit on USB3333,
but the symptoms look very similar.

Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Volodymyr Mieshkov <x0182794@ti.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-omap.c

@@ -43,6 +43,7 @@
 #include <linux/regulator/consumer.h>
 #include <linux/pm_runtime.h>
 #include <linux/gpio.h>
+#include <linux/clk.h>
 
 /* EHCI Register Set */
 #define EHCI_INSNREG04					(0xA0)
@@ -55,6 +56,15 @@
 #define	EHCI_INSNREG05_ULPI_EXTREGADD_SHIFT		8
 #define	EHCI_INSNREG05_ULPI_WRDATA_SHIFT		0
 
+/* Errata i693 */
+static struct clk	*utmi_p1_fck;
+static struct clk	*utmi_p2_fck;
+static struct clk	*xclk60mhsp1_ck;
+static struct clk	*xclk60mhsp2_ck;
+static struct clk	*usbhost_p1_fck;
+static struct clk	*usbhost_p2_fck;
+static struct clk	*init_60m_fclk;
+
 /*-------------------------------------------------------------------------*/
 
 static const struct hc_driver ehci_omap_hc_driver;
@@ -70,6 +80,41 @@ static inline u32 ehci_read(void __iomem *base, u32 reg)
 	return __raw_readl(base + reg);
 }
 
+/* Erratum i693 workaround sequence */
+static void omap_ehci_erratum_i693(struct ehci_hcd *ehci)
+{
+	int ret = 0;
+
+	/* Switch to the internal 60 MHz clock */
+	ret = clk_set_parent(utmi_p1_fck, init_60m_fclk);
+	if (ret != 0)
+		ehci_err(ehci, "init_60m_fclk set parent"
+			"failed error:%d\n", ret);
+
+	ret = clk_set_parent(utmi_p2_fck, init_60m_fclk);
+	if (ret != 0)
+		ehci_err(ehci, "init_60m_fclk set parent"
+			"failed error:%d\n", ret);
+
+	clk_enable(usbhost_p1_fck);
+	clk_enable(usbhost_p2_fck);
+
+	/* Wait 1ms and switch back to the external clock */
+	mdelay(1);
+	ret = clk_set_parent(utmi_p1_fck, xclk60mhsp1_ck);
+	if (ret != 0)
+		ehci_err(ehci, "xclk60mhsp1_ck set parent"
+			"failed error:%d\n", ret);
+
+	ret = clk_set_parent(utmi_p2_fck, xclk60mhsp2_ck);
+	if (ret != 0)
+		ehci_err(ehci, "xclk60mhsp2_ck set parent"
+			"failed error:%d\n", ret);
+
+	clk_disable(usbhost_p1_fck);
+	clk_disable(usbhost_p2_fck);
+}
+
 static void omap_ehci_soft_phy_reset(struct platform_device *pdev, u8 port)
 {
 	struct usb_hcd	*hcd = dev_get_drvdata(&pdev->dev);
@@ -100,6 +145,50 @@ static void omap_ehci_soft_phy_reset(struct platform_device *pdev, u8 port)
 	}
 }
 
+static int omap_ehci_hub_control(
+	struct usb_hcd	*hcd,
+	u16		typeReq,
+	u16		wValue,
+	u16		wIndex,
+	char		*buf,
+	u16		wLength
+)
+{
+	struct ehci_hcd	*ehci = hcd_to_ehci(hcd);
+	u32 __iomem *status_reg = &ehci->regs->port_status[
+				(wIndex & 0xff) - 1];
+	u32		temp;
+	unsigned long	flags;
+	int		retval = 0;
+
+	spin_lock_irqsave(&ehci->lock, flags);
+
+	if (typeReq == SetPortFeature && wValue == USB_PORT_FEAT_SUSPEND) {
+		temp = ehci_readl(ehci, status_reg);
+		if ((temp & PORT_PE) == 0 || (temp & PORT_RESET) != 0) {
+			retval = -EPIPE;
+			goto done;
+		}
+
+		temp &= ~PORT_WKCONN_E;
+		temp |= PORT_WKDISC_E | PORT_WKOC_E;
+		ehci_writel(ehci, temp | PORT_SUSPEND, status_reg);
+
+		omap_ehci_erratum_i693(ehci);
+
+		set_bit((wIndex & 0xff) - 1, &ehci->suspended_ports);
+		goto done;
+	}
+
+	spin_unlock_irqrestore(&ehci->lock, flags);
+
+	/* Handle the hub control events here */
+	return ehci_hub_control(hcd, typeReq, wValue, wIndex, buf, wLength);
+done:
+	spin_unlock_irqrestore(&ehci->lock, flags);
+	return retval;
+}
+
 static void disable_put_regulator(
 		struct ehci_hcd_omap_platform_data *pdata)
 {
@@ -264,8 +353,76 @@ static int ehci_hcd_omap_probe(struct platform_device *pdev)
 	/* root ports should always stay powered */
 	ehci_port_power(omap_ehci, 1);
 
+	/* get clocks */
+	utmi_p1_fck = clk_get(dev, "utmi_p1_gfclk");
+	if (IS_ERR(utmi_p1_fck)) {
+		ret = PTR_ERR(utmi_p1_fck);
+		dev_err(dev, "utmi_p1_gfclk failed error:%d\n",	ret);
+		goto err_add_hcd;
+	}
+
+	xclk60mhsp1_ck = clk_get(dev, "xclk60mhsp1_ck");
+	if (IS_ERR(xclk60mhsp1_ck)) {
+		ret = PTR_ERR(xclk60mhsp1_ck);
+		dev_err(dev, "xclk60mhsp1_ck failed error:%d\n", ret);
+		goto err_utmi_p1_fck;
+	}
+
+	utmi_p2_fck = clk_get(dev, "utmi_p2_gfclk");
+	if (IS_ERR(utmi_p2_fck)) {
+		ret = PTR_ERR(utmi_p2_fck);
+		dev_err(dev, "utmi_p2_gfclk failed error:%d\n", ret);
+		goto err_xclk60mhsp1_ck;
+	}
+
+	xclk60mhsp2_ck = clk_get(dev, "xclk60mhsp2_ck");
+	if (IS_ERR(xclk60mhsp2_ck)) {
+		ret = PTR_ERR(xclk60mhsp2_ck);
+		dev_err(dev, "xclk60mhsp2_ck failed error:%d\n", ret);
+		goto err_utmi_p2_fck;
+	}
+
+	usbhost_p1_fck = clk_get(dev, "usb_host_hs_utmi_p1_clk");
+	if (IS_ERR(usbhost_p1_fck)) {
+		ret = PTR_ERR(usbhost_p1_fck);
+		dev_err(dev, "usbhost_p1_fck failed error:%d\n", ret);
+		goto err_xclk60mhsp2_ck;
+	}
+
+	usbhost_p2_fck = clk_get(dev, "usb_host_hs_utmi_p2_clk");
+	if (IS_ERR(usbhost_p2_fck)) {
+		ret = PTR_ERR(usbhost_p2_fck);
+		dev_err(dev, "usbhost_p2_fck failed error:%d\n", ret);
+		goto err_usbhost_p1_fck;
+	}
+
+	init_60m_fclk = clk_get(dev, "init_60m_fclk");
+	if (IS_ERR(init_60m_fclk)) {
+		ret = PTR_ERR(init_60m_fclk);
+		dev_err(dev, "init_60m_fclk failed error:%d\n", ret);
+		goto err_usbhost_p2_fck;
+	}
+
 	return 0;
 
+err_usbhost_p2_fck:
+	clk_put(usbhost_p2_fck);
+
+err_usbhost_p1_fck:
+	clk_put(usbhost_p1_fck);
+
+err_xclk60mhsp2_ck:
+	clk_put(xclk60mhsp2_ck);
+
+err_utmi_p2_fck:
+	clk_put(utmi_p2_fck);
+
+err_xclk60mhsp1_ck:
+	clk_put(xclk60mhsp1_ck);
+
+err_utmi_p1_fck:
+	clk_put(utmi_p1_fck);
+
 err_add_hcd:
 	disable_put_regulator(pdata);
 	pm_runtime_put_sync(dev);
@@ -294,6 +451,15 @@ static int ehci_hcd_omap_remove(struct platform_device *pdev)
 	disable_put_regulator(dev->platform_data);
 	iounmap(hcd->regs);
 	usb_put_hcd(hcd);
+
+	clk_put(utmi_p1_fck);
+	clk_put(utmi_p2_fck);
+	clk_put(xclk60mhsp1_ck);
+	clk_put(xclk60mhsp2_ck);
+	clk_put(usbhost_p1_fck);
+	clk_put(usbhost_p2_fck);
+	clk_put(init_60m_fclk);
+
 	pm_runtime_put_sync(dev);
 	pm_runtime_disable(dev);
 
@@ -364,7 +530,7 @@ static const struct hc_driver ehci_omap_hc_driver = {
 	 * root hub support
 	 */
 	.hub_status_data	= ehci_hub_status_data,
-	.hub_control		= ehci_hub_control,
+	.hub_control		= omap_ehci_hub_control,
 	.bus_suspend		= ehci_bus_suspend,
 	.bus_resume		= ehci_bus_resume,