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>

1 files changed, 72 insertions, 0 deletions

diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c
index a516af28c29..7359bcbe417 100644
--- 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