USB: ehci: tegra: fix USB1 port reset issue

Tegra USB1 port needs to issue Port Reset twice internally, otherwise it
fails to enumerate devices attached to it

Signed-off-by: Jim Lin <jilin@nvidia.com>
Signed-off-by: Olof Johansson <olofj@chromium.org>
[ squash two patches into one and minor style cleanups ]
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c
index a516af2..7359bcb 100644 (file)
--- a/drivers/usb/host/ehci-tegra.c
+++ b/drivers/usb/host/ehci-tegra.c
@@ -58,6 +58,71 @@ static void tegra_ehci_power_down(struct usb_hcd *hcd)
        clk_disable(tegra->emc_clk);
 }
 
+static int tegra_ehci_internal_port_reset(
+       struct ehci_hcd *ehci,
+       u32 __iomem     *portsc_reg
+)
+{
+       u32             temp;
+       unsigned long   flags;
+       int             retval = 0;
+       int             i, tries;
+       u32             saved_usbintr;
+
+       spin_lock_irqsave(&ehci->lock, flags);
+       saved_usbintr = ehci_readl(ehci, &ehci->regs->intr_enable);
+       /* disable USB interrupt */
+       ehci_writel(ehci, 0, &ehci->regs->intr_enable);
+       spin_unlock_irqrestore(&ehci->lock, flags);
+
+       /*
+        * Here we have to do Port Reset at most twice for
+        * Port Enable bit to be set.
+        */
+       for (i = 0; i < 2; i++) {
+               temp = ehci_readl(ehci, portsc_reg);
+               temp |= PORT_RESET;
+               ehci_writel(ehci, temp, portsc_reg);
+               mdelay(10);
+               temp &= ~PORT_RESET;
+               ehci_writel(ehci, temp, portsc_reg);
+               mdelay(1);
+               tries = 100;
+               do {
+                       mdelay(1);
+                       /*
+                        * Up to this point, Port Enable bit is
+                        * expected to be set after 2 ms waiting.
+                        * USB1 usually takes extra 45 ms, for safety,
+                        * we take 100 ms as timeout.
+                        */
+                       temp = ehci_readl(ehci, portsc_reg);
+               } while (!(temp & PORT_PE) && tries--);
+               if (temp & PORT_PE)
+                       break;
+       }
+       if (i == 2)
+               retval = -ETIMEDOUT;
+
+       /*
+        * Clear Connect Status Change bit if it's set.
+        * We can't clear PORT_PEC. It will also cause PORT_PE to be cleared.
+        */
+       if (temp & PORT_CSC)
+               ehci_writel(ehci, PORT_CSC, portsc_reg);
+
+       /*
+        * Write to clear any interrupt status bits that might be set
+        * during port reset.
+        */
+       temp = ehci_readl(ehci, &ehci->regs->status);
+       ehci_writel(ehci, temp, &ehci->regs->status);
+
+       /* restore original interrupt enable bits */
+       ehci_writel(ehci, saved_usbintr, &ehci->regs->intr_enable);
+       return retval;
+}
+
 static int tegra_ehci_hub_control(
        struct usb_hcd  *hcd,
        u16             typeReq,
@@ -121,6 +186,13 @@ static int tegra_ehci_hub_control(
                goto done;
        }
 
+       /* For USB1 port we need to issue Port Reset twice internally */
+       if (tegra->phy->instance == 0 &&
+          (typeReq == SetPortFeature && wValue == USB_PORT_FEAT_RESET)) {
+               spin_unlock_irqrestore(&ehci->lock, flags);
+               return tegra_ehci_internal_port_reset(ehci, status_reg);
+       }
+
        /*
         * Tegra host controller will time the resume operation to clear the bit
         * when the port control state switches to HS or FS Idle. This behavior