ehci-hub: improved over-current recovery

According to the USB Specification Revision 2.0 chapter 11.12.5
a hub experiencing an over-current condition must place all
affected ports in the powered-off state. It seems that some root
hubs need port power to be cycled by software in order to get back
to normal functionality after an over-current condition ... like
the EHCI implementation on an MPC8343E.

Signed-off-by: Christian Engelmayer <christian.engelmayer@frequentis.com>
Signed-off-by: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 27291f5..71aeca0 100644 (file)
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -647,9 +647,24 @@ static int ehci_hub_control (
                        status |= 1 << USB_PORT_FEAT_C_CONNECTION;
                if (temp & PORT_PEC)
                        status |= 1 << USB_PORT_FEAT_C_ENABLE;
-               if ((temp & PORT_OCC) && !ignore_oc)
+
+               if ((temp & PORT_OCC) && !ignore_oc){
                        status |= 1 << USB_PORT_FEAT_C_OVER_CURRENT;
 
+                       /*
+                        * Hubs should disable port power on over-current.
+                        * However, not all EHCI implementations do this
+                        * automatically, even if they _do_ support per-port
+                        * power switching; they're allowed to just limit the
+                        * current.  khubd will turn the power back on.
+                        */
+                       if (HCS_PPC (ehci->hcs_params)){
+                               ehci_writel(ehci,
+                                       temp & ~(PORT_RWC_BITS | PORT_POWER),
+                                       status_reg);
+                       }
+               }
+
                /* whoever resumes must GetPortStatus to complete it!! */
                if (temp & PORT_RESUME) {