On 3/29/2012 7:42 AM, Paul Zimmerman wrote:
From: Paul Zimmerman
Sent: Wednesday, March 28, 2012 3:55 PM
From: Paul Zimmerman
Sent: Wednesday, March 28, 2012 1:52 PM
So the Update Transfer command is required.
< snip>
The reason for this is that the core will cache a certain number
of TRBs in its internal memory. If it already has a TRB in its
cache, then even though the software updates that TRB and sets
its HWO bit, the core won't see that unless an Update Transfer
command is issued to tell it to flush its TRB cache and reload
it.
Now, it's possible that if the TRB list is big enough, and
software stays far enough ahead of the hardware, this situation
won't arise. But I don't think you can depend on that always
being the case. So for reliable operation, you should issue an
Update Transfer command whenever you update one or more TRBs
that are part of an active transfer.
Something like the attached patch, I think. Warning: this has
been compile-tested only! Pratyush, maybe you can use this as
a starting point?
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 5255fe9..6529a81 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -930,10 +930,12 @@ static int __dwc3_gadget_kick_transfer(struct dwc3_ep *dep, u16 cmd_param,
}
dep->flags |= DWC3_EP_BUSY;
- dep->res_trans_idx = dwc3_gadget_ep_get_transfer_index(dwc,
- dep->number);
- WARN_ON_ONCE(!dep->res_trans_idx);
+ if (start_new) {
+ dep->res_trans_idx = dwc3_gadget_ep_get_transfer_index(dwc,
+ dep->number);
+ WARN_ON_ONCE(!dep->res_trans_idx);
+ }
return 0;
}
@@ -979,16 +981,22 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
* until the next request is queued. The following
* code is handling exactly that.
*/
- if (dep->flags& DWC3_EP_PENDING_REQUEST) {
+ if ((dep->flags& DWC3_EP_PENDING_REQUEST) ||
+ (usb_endpoint_xfer_isoc(dep->desc)&&
+ (dep->flags& DWC3_EP_BUSY))) {
int ret;
- int start_trans;
+ int start_trans = 1;
+ int trans_idx = dep->res_trans_idx;
- start_trans = 1;
if (usb_endpoint_xfer_isoc(dep->desc)&&
- (dep->flags& DWC3_EP_BUSY))
+ (dep->flags& DWC3_EP_BUSY)) {
start_trans = 0;
+ WARN_ON_ONCE(!trans_idx);
+ } else {
+ trans_idx = 0;
+ }
- ret = __dwc3_gadget_kick_transfer(dep, 0, start_trans);
+ ret = __dwc3_gadget_kick_transfer(dep, trans_idx, start_trans);
if (ret&& ret != -EBUSY) {
struct dwc3 *dwc = dep->dwc;
Hi Pratyush,
I tried my "isoc support for gadget zero and usbtest" patches with
the dwc3 driver with the above patch, and the isoc IN tests from
usbtest still didn't work. I discovered that I needed to queue up
8 requests in source_sink_start_ep(), or else the transfer would
stop after the first 4 packets were sent.
Yes exactly, I had also works on the similar line.
Thanks a lot for all these patches. I will apply them and will test.
Regards
Pratyush
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