USB: ehci-omap: Fix resume failures after bus suspend

[safe/jmp/linux-2.6] / drivers / usb / host / ehci-omap.c

diff --git a/drivers/usb/host/ehci-omap.c b/drivers/usb/host/ehci-omap.c
index 992d963..8905ba4 100644 (file)
--- a/drivers/usb/host/ehci-omap.c
+++ b/drivers/usb/host/ehci-omap.c
@@ -116,6 +116,8 @@
 #define        OMAP_UHH_DEBUG_CSR                              (0x44)
 
 /* EHCI Register Set */
+#define EHCI_INSNREG04                                 (0xA0)
+#define EHCI_INSNREG04_DISABLE_UNSUSPEND               (1 << 5)
 #define        EHCI_INSNREG05_ULPI                             (0xA4)
 #define        EHCI_INSNREG05_ULPI_CONTROL_SHIFT               31
 #define        EHCI_INSNREG05_ULPI_PORTSEL_SHIFT               24
@@ -382,6 +384,18 @@ static int omap_start_ehc(struct ehci_hcd_omap *omap, struct usb_hcd *hcd)
        dev_dbg(omap->dev, "UHH setup done, uhh_hostconfig=%x\n", reg);
 
 
+       /*
+        * An undocumented "feature" in the OMAP3 EHCI controller,
+        * causes suspended ports to be taken out of suspend when
+        * the USBCMD.Run/Stop bit is cleared (for example when
+        * we do ehci_bus_suspend).
+        * This breaks suspend-resume if the root-hub is allowed
+        * to suspend. Writing 1 to this undocumented register bit
+        * disables this feature and restores normal behavior.
+        */
+       ehci_omap_writel(omap->ehci_base, EHCI_INSNREG04,
+                               EHCI_INSNREG04_DISABLE_UNSUSPEND);
+
        if ((omap->port_mode[0] == EHCI_HCD_OMAP_MODE_TLL) ||
                (omap->port_mode[1] == EHCI_HCD_OMAP_MODE_TLL) ||
                        (omap->port_mode[2] == EHCI_HCD_OMAP_MODE_TLL)) {