usb: dwc3: gadget: don't wrap around the TRB poll on non-ISOC
If we have a non-ISOC endpoint, we will not have a Link TRB
pointing to the beginning of the TRB pool. On such endpoints,
we don't want to let the driver wrap around the TRB pool
otherwise controller will hang waiting for a valid TRB.
Cc: stable@vger.kernel.org
Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index d121e73..48b2d0d 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -826,6 +826,7 @@
{
struct dwc3_request *req, *n;
u32 trbs_left;
+ u32 max;
unsigned int last_one = 0;
BUILD_BUG_ON_NOT_POWER_OF_2(DWC3_TRB_NUM);
@@ -833,6 +834,13 @@
/* the first request must not be queued */
trbs_left = (dep->busy_slot - dep->free_slot) & DWC3_TRB_MASK;
+ /* Can't wrap around on a non-isoc EP since there's no link TRB */
+ if (!usb_endpoint_xfer_isoc(dep->desc)) {
+ max = DWC3_TRB_NUM - (dep->free_slot & DWC3_TRB_MASK);
+ if (trbs_left > max)
+ trbs_left = max;
+ }
+
/*
* If busy & slot are equal than it is either full or empty. If we are
* starting to process requests then we are empty. Otherwise we are