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authorPratyush Anand <pratyush.anand@st.com>2012-07-06 15:19:10 +0530
committerFelipe Balbi <balbi@ti.com>2012-08-09 14:18:39 +0300
commit57911504a93909034ba5b90c20f3e6df8409ebd8 (patch)
tree439a00a1a9991217dcb36d4acf9aa7e6e04d47ca /drivers/usb/dwc3
parent79c9046ec52b5aaa9f055e3d928d676dd37a6f9d (diff)
usb: dwc3: gadget: Fix dwc3_stop_active_transfer for synchronization delay
dwc3_stop_active_transfer has been called from two places. After each calling of this function , we should allow 100 us delay to synchronize with interconnect. It would be better if we put this delay in that function only, rather than into calling routine of this function. Signed-off-by: Pratyush Anand <pratyush.anand@st.com> Reported-by: Michel Sanches <michel.sanches@st.com> Signed-off-by: Felipe Balbi <balbi@ti.com>
Diffstat (limited to 'drivers/usb/dwc3')
-rw-r--r--drivers/usb/dwc3/gadget.c43
1 files changed, 22 insertions, 21 deletions
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index fc059107c05..dd5945ca9c8 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -563,27 +563,7 @@ static void dwc3_remove_requests(struct dwc3 *dwc, struct dwc3_ep *dep)
if (!list_empty(&dep->req_queued)) {
dwc3_stop_active_transfer(dwc, dep->number);
- /*
- * NOTICE: We are violating what the Databook says about the
- * EndTransfer command. Ideally we would _always_ wait for the
- * EndTransfer Command Completion IRQ, but that's causing too
- * much trouble synchronizing between us and gadget driver.
- *
- * We have discussed this with the IP Provider and it was
- * suggested to giveback all requests here, but give HW some
- * extra time to synchronize with the interconnect. We're using
- * an arbitraty 100us delay for that.
- *
- * Note also that a similar handling was tested by Synopsys
- * (thanks a lot Paul) and nothing bad has come out of it.
- * In short, what we're doing is:
- *
- * - Issue EndTransfer WITH CMDIOC bit set
- * - Wait 100us
- * - giveback all requests to gadget driver
- */
- udelay(100);
-
+ /* - giveback all requests to gadget driver */
while (!list_empty(&dep->req_queued)) {
req = next_request(&dep->req_queued);
@@ -1875,6 +1855,25 @@ static void dwc3_stop_active_transfer(struct dwc3 *dwc, u32 epnum)
if (!dep->resource_index)
return;
+ /*
+ * NOTICE: We are violating what the Databook says about the
+ * EndTransfer command. Ideally we would _always_ wait for the
+ * EndTransfer Command Completion IRQ, but that's causing too
+ * much trouble synchronizing between us and gadget driver.
+ *
+ * We have discussed this with the IP Provider and it was
+ * suggested to giveback all requests here, but give HW some
+ * extra time to synchronize with the interconnect. We're using
+ * an arbitraty 100us delay for that.
+ *
+ * Note also that a similar handling was tested by Synopsys
+ * (thanks a lot Paul) and nothing bad has come out of it.
+ * In short, what we're doing is:
+ *
+ * - Issue EndTransfer WITH CMDIOC bit set
+ * - Wait 100us
+ */
+
cmd = DWC3_DEPCMD_ENDTRANSFER;
cmd |= DWC3_DEPCMD_HIPRI_FORCERM | DWC3_DEPCMD_CMDIOC;
cmd |= DWC3_DEPCMD_PARAM(dep->resource_index);
@@ -1882,6 +1881,8 @@ static void dwc3_stop_active_transfer(struct dwc3 *dwc, u32 epnum)
ret = dwc3_send_gadget_ep_cmd(dwc, dep->number, cmd, &params);
WARN_ON_ONCE(ret);
dep->resource_index = 0;
+
+ udelay(100);
}
static void dwc3_stop_active_transfers(struct dwc3 *dwc)