From: Konrad Leszczynski <konrad.leszczynski@xxxxxxxxx>
if Start Transfer command fails, let's try a little
harder to figure out why the command failed and give
slightly better return codes. This will be usefulf
or isochronous endpoints, at least, which could
decide to retry a given request.
Signed-off-by: Konrad Leszczynski <konrad.leszczynski@xxxxxxxxx>
Signed-off-by: Rafal Redzimski <rafal.f.redzimski@xxxxxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
---
drivers/usb/dwc3/core.h | 4 ++++
drivers/usb/dwc3/gadget.c | 33 ++++++++++++++++++++++++++++++---
2 files changed, 34 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index bbbd1789596e..87df6dd20d23 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -970,6 +970,10 @@ struct dwc3_event_depevt {
#define DEPEVT_STATUS_CONTROL_DATA 1
#define DEPEVT_STATUS_CONTROL_STATUS 2
+/* In response to Start Transfer */
+#define DEPEVT_TRANSFER_NO_RESOURCE 1
+#define DEPEVT_TRANSFER_BUS_EXPIRY 2
+
u32 parameters:16;
} __packed;
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 6929775bde57..498a79870c8c 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -287,12 +287,39 @@ int dwc3_send_gadget_ep_cmd(struct dwc3 *dwc, unsigned ep,
do {
reg = dwc3_readl(dwc->regs, DWC3_DEPCMD(ep));
if (!(reg & DWC3_DEPCMD_CMDACT)) {
+ int cmd_status = DWC3_DEPCMD_STATUS(reg);
+
dwc3_trace(trace_dwc3_gadget,
"Command Complete --> %d",
- DWC3_DEPCMD_STATUS(reg));
- if (DWC3_DEPCMD_STATUS(reg))
+ cmd_status);
+
+ switch (cmd_status) {
+ case 0:
+ ret = 0;
+ break;
+ case DEPEVT_TRANSFER_NO_RESOURCE:
+ dwc3_trace(trace_dwc3_gadget, "%s: no resource available");
+ ret = -EINVAL;
break;
- ret = 0;
+ case DEPEVT_TRANSFER_BUS_EXPIRY:
+ /*
+ * SW issues START TRANSFER command to
+ * isochronous ep with future frame interval. If
+ * future interval time has already passed when
+ * core receives the command, it will respond
+ * with an error status of 'Bus Expiry'.
+ *
+ * Instead of always returning -EINVAL, let's
+ * give a hint to the gadget driver that this is
+ * the case by returning -EAGAIN.
+ */
+ dwc3_trace(trace_dwc3_gadget, "%s: bus expiry");
+ ret = -EAGAIN;
+ break;
+ default:
+ dev_WARN(dwc->dev, "UNKNOWN cmd status\n");
+ }
+
break;
}
--
2.8.1
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
