USB: EHCI: clear PHCD before resuming
Alek Du [Mon, 10 May 2010 03:17:49 +0000 (11:17 +0800)]
This is a bug fix for PHCD (phy clock disable) low power feature:
After PHCD is set, any write to PORTSC register is illegal, so when
resume ports, clear PHCD bit first.

Signed-off-by: Alek Du <alek.du@intel.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/ehci-hub.c

index c440181..ef95622 100644 (file)
@@ -294,6 +294,16 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
        /* manually resume the ports we suspended during bus_suspend() */
        i = HCS_N_PORTS (ehci->hcs_params);
        while (i--) {
+               /* clear phy low power mode before resume */
+               if (ehci->has_hostpc) {
+                       u32 __iomem     *hostpc_reg =
+                               (u32 __iomem *)((u8 *)ehci->regs
+                               + HOSTPC0 + 4 * (i & 0xff));
+                       temp = ehci_readl(ehci, hostpc_reg);
+                       ehci_writel(ehci, temp & ~HOSTPC_PHCD,
+                               hostpc_reg);
+                       mdelay(5);
+               }
                temp = ehci_readl(ehci, &ehci->regs->port_status [i]);
                temp &= ~(PORT_RWC_BITS | PORT_WAKE_BITS);
                if (test_bit(i, &ehci->bus_suspended) &&
@@ -678,6 +688,13 @@ static int ehci_hub_control (
                        if (temp & PORT_SUSPEND) {
                                if ((temp & PORT_PE) == 0)
                                        goto error;
+                               /* clear phy low power mode before resume */
+                               if (hostpc_reg) {
+                                       temp1 = ehci_readl(ehci, hostpc_reg);
+                                       ehci_writel(ehci, temp1 & ~HOSTPC_PHCD,
+                                               hostpc_reg);
+                                       mdelay(5);
+                               }
                                /* resume signaling for 20 msec */
                                temp &= ~(PORT_RWC_BITS | PORT_WAKE_BITS);
                                ehci_writel(ehci, temp | PORT_RESUME,