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usb: dwc3: gadget: check if dep->frame_number is still valid

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Gadget driver may take an unbounded amount of time to queue requests
after XferNotReady. This is important for isochronous endpoints which
need to be started for a specific (micro-)frame.

If we fail to start a transfer for isochronous endpoint, let's try
queueing to a future interval and see if that helps. We will stop trying
if we fail a start transfer for 5 intervals in the future.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This commit is contained in:
Felipe Balbi 2018-08-14 10:42:43 +03:00
parent 3451f6affa
commit d53701067f
2 changed files with 13 additions and 3 deletions
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1
drivers/usb/dwc3/core.h
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@ -37,6 +37,7 @@
#define DWC3_EP0_SETUP_SIZE 512
#define DWC3_ENDPOINTS_NUM 32
#define DWC3_XHCI_RESOURCES_NUM 2
#define DWC3_ISOC_MAX_RETRIES 5
#define DWC3_SCRATCHBUF_SIZE 4096 /* each buffer is assumed to be 4KiB */
#define DWC3_EVENT_BUFFERS_SIZE 4096

15
drivers/usb/dwc3/gadget.c
View File

@ -27,7 +27,7 @@
#include "gadget.h"
#include "io.h"
#define DWC3_ALIGN_FRAME(d) (((d)->frame_number + (d)->interval) \
#define DWC3_ALIGN_FRAME(d, n) (((d)->frame_number + ((d)->interval * (n))) \
& ~((d)->interval - 1))
/**
@ -1384,6 +1384,8 @@ static int dwc3_gadget_start_isoc_quirk(struct dwc3_ep *dep)
static int __dwc3_gadget_start_isoc(struct dwc3_ep *dep)
{
struct dwc3 *dwc = dep->dwc;
int ret;
int i;
if (list_empty(&dep->pending_list)) {
dep->flags |= DWC3_EP_PENDING_REQUEST;
@ -1400,8 +1402,15 @@ static int __dwc3_gadget_start_isoc(struct dwc3_ep *dep)
return dwc3_gadget_start_isoc_quirk(dep);
}
dep->frame_number = DWC3_ALIGN_FRAME(dep);
return __dwc3_gadget_kick_transfer(dep);
for (i = 0; i < DWC3_ISOC_MAX_RETRIES; i++) {
dep->frame_number = DWC3_ALIGN_FRAME(dep, i + 1);
ret = __dwc3_gadget_kick_transfer(dep);
if (ret != -EAGAIN)
break;
}
return ret;
}
static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)