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usb: dwc3: gadget: fix for short pkts during chained xfers 

DWC3 has one interesting peculiarity with chained
transfers. If we setup N chained transfers and we
get a short packet before processing all N TRBs,
DWC3 will (conditionally) issue a XferComplete or
XferInProgress event and retire all TRBs from the
one which got a short packet to the last without
clearing their HWO bits.

This means SW must clear HWO bit manually, which
this patch is doing.

Cc: <stable@vger.kernel.org>
Cc: Brian E Rogers <brian.e.rogers@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This commit is contained in:
Felipe Balbi 2016-08-10 11:13:26 +03:00
parent c7de573471
commit e5b36ae2f8
1 changed files with 20 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
drivers/usb/dwc3/gadget.c
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@ -1955,7 +1955,8 @@ static void dwc3_gadget_free_endpoints(struct dwc3 *dwc)
static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep, static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
struct dwc3_request *req, struct dwc3_trb *trb, struct dwc3_request *req, struct dwc3_trb *trb,
const struct dwc3_event_depevt *event, int status) const struct dwc3_event_depevt *event, int status,
int chain)
{ {
unsigned int count; unsigned int count;
unsigned int s_pkt = 0; unsigned int s_pkt = 0;
@ -1964,6 +1965,19 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
dep->queued_requests--; dep->queued_requests--;
trace_dwc3_complete_trb(dep, trb); trace_dwc3_complete_trb(dep, trb);
/*
* If we're in the middle of series of chained TRBs and we
* receive a short transfer along the way, DWC3 will skip
* through all TRBs including the last TRB in the chain (the
* where CHN bit is zero. DWC3 will also avoid clearing HWO
* bit and SW has to do it manually.
*
* We're going to do that here to avoid problems of HW trying
* to use bogus TRBs for transfers.
*/
if (chain && (trb->ctrl & DWC3_TRB_CTRL_HWO))
trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
if ((trb->ctrl & DWC3_TRB_CTRL_HWO) && status != -ESHUTDOWN) if ((trb->ctrl & DWC3_TRB_CTRL_HWO) && status != -ESHUTDOWN)
/* /*
* We continue despite the error. There is not much we * We continue despite the error. There is not much we
@ -1975,6 +1989,7 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
*/ */
dev_err(dwc->dev, "%s's TRB (%p) still owned by HW\n", dev_err(dwc->dev, "%s's TRB (%p) still owned by HW\n",
dep->name, trb); dep->name, trb);
count = trb->size & DWC3_TRB_SIZE_MASK; count = trb->size & DWC3_TRB_SIZE_MASK;
if (dep->direction) { if (dep->direction) {
@ -2036,10 +2051,13 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
int ret; int ret;
do { do {
int chain;
req = next_request(&dep->started_list); req = next_request(&dep->started_list);
if (WARN_ON_ONCE(!req)) if (WARN_ON_ONCE(!req))
return 1; return 1;
chain = req->request.num_mapped_sgs > 0;
i = 0; i = 0;
do { do {
slot = req->first_trb_index + i; slot = req->first_trb_index + i;
@ -2049,9 +2067,8 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
trb = &dep->trb_pool[slot]; trb = &dep->trb_pool[slot];
count += trb->size & DWC3_TRB_SIZE_MASK; count += trb->size & DWC3_TRB_SIZE_MASK;
ret = __dwc3_cleanup_done_trbs(dwc, dep, req, trb, ret = __dwc3_cleanup_done_trbs(dwc, dep, req, trb,
event, status); event, status, chain);
if (ret) if (ret)
break; break;
} while (++i < req->request.num_mapped_sgs); } while (++i < req->request.num_mapped_sgs);