ENGR00155880 USB device: Fix RNDIS Full Speed hang during initialization

When setup irq is received, the status phase of the transfer is primed
on ep0 before the data phase. The usb requests are added to the list
of transfer descriptors (maintained by driver) in reverse of their
expected completion order. Completion order is data followed by status,
however the list of tds contains status followed by data.

Upon completion of the data request, the irq handler proceeds to check
the 1st td in the list -- the status request. In full speed mode,
the status phase has not yet completed at this time, so the td's
ACTIVE bit is still set. This leads irq handler to ignore the completion
interrupt without checking the actual td for the data request that caused
the interrupt.

In high speed mode, this issue does not bear itself out because the status
request also completes by the time the irq handler goes to process the data
completion interrupt.

The simple fix for this issue is to prime the status request AFTER the data
request, so that the list of tds maintained by the driver contains the tds
in the order of expected completion.

Signed-off-by: Anish Trivedi <anish@freescale.com>

diff --git a/drivers/usb/gadget/arcotg_udc.c b/drivers/usb/gadget/arcotg_udc.c
index f33ba52f288ef2e3e9f6d8dbce254df985d9a845..ccd8591134a670e26ad18530eb4054380b876848 100755 (executable)
--- a/drivers/usb/gadget/arcotg_udc.c
+++ b/drivers/usb/gadget/arcotg_udc.c
@@ -1577,17 +1577,6 @@ static void setup_received_irq(struct fsl_udc *udc,
        unsigned mA = 500;
        udc_reset_ep_queue(udc, 0);
 
-       if (wLength) {
-               int dir;
-               dir = EP_DIR_IN;
-               if (setup->bRequestType & USB_DIR_IN) {
-                       dir = EP_DIR_OUT;
-               }
-               spin_unlock(&udc->lock);
-               if (ep0_prime_status(udc, dir))
-                       ep0stall(udc);
-               spin_lock(&udc->lock);
-       }
        /* We process some stardard setup requests here */
        switch (setup->bRequest) {
        case USB_REQ_GET_STATUS:
@@ -1689,9 +1678,16 @@ static void setup_received_irq(struct fsl_udc *udc,
                spin_unlock(&udc->lock);
                if (udc->driver->setup(&udc->gadget,
                                &udc->local_setup_buff) < 0) {
-                       /* cancel status phase */
+                       /* cancel all requests on ep0 */
                        udc_reset_ep_queue(udc, 0);
                        ep0stall(udc);
+               } else {
+                       /* prime the status phase */
+                       int dir = EP_DIR_IN;
+                       if (setup->bRequestType & USB_DIR_IN)
+                               dir = EP_DIR_OUT;
+                       if (ep0_prime_status(udc, dir))
+                               ep0stall(udc);
                }
        } else {
                /* No data phase, IN status from gadget */