Issue an Update Transfer command after queuing a request to an isoc
EP with an active transfer. This is required according to the dwc3
databook. Pratyush Anand reports that this fixes a problem he was
having with Isoc IN transfers.
Signed-off-by: Paul Zimmerman <paulz@xxxxxxxxxxxx>
---
Pratyush, this is a cleaned-up version of the original patch, which
also updates the comment in __dwc3_gadget_ep_queue() to describe
this case. If you could, please test this version and give your
tested-by if it works OK.
drivers/usb/dwc3/gadget.c | 45 ++++++++++++++++++++++++++++-----------------
1 files changed, 28 insertions(+), 17 deletions(-)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 5255fe9..cee4e45 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;
}
@@ -967,28 +969,37 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
list_add_tail(&req->list, &dep->request_list);
+ if (usb_endpoint_xfer_isoc(dep->desc) && (dep->flags & DWC3_EP_BUSY))
+ dep->flags |= DWC3_EP_PENDING_REQUEST;
+
/*
- * There is one special case: XferNotReady with
- * empty list of requests. We need to kick the
- * transfer here in that situation, otherwise
- * we will be NAKing forever.
+ * There are two special cases:
*
- * If we get XferNotReady before gadget driver
- * has a chance to queue a request, we will ACK
- * the IRQ but won't be able to receive the data
- * until the next request is queued. The following
- * code is handling exactly that.
+ * 1. XferNotReady with empty list of requests. We need to kick the
+ * transfer here in that situation, otherwise we will be NAKing
+ * forever. If we get XferNotReady before gadget driver has a
+ * chance to queue a request, we will ACK the IRQ but won't be
+ * able to receive the data until the next request is queued.
+ * The following code is handling exactly that.
+ *
+ * 2. XferInProgress on Isoc EP with an active transfer. We need to
+ * kick the transfer here after queuing a request, otherwise the
+ * core may not see the modified TRB(s).
*/
if (dep->flags & DWC3_EP_PENDING_REQUEST) {
- int ret;
- int start_trans;
+ int ret;
+ int start_trans = 1;
+ u8 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;
--
Paul
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