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usb: dwc3: gadget: Remove END_TRANSFER delay

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We had a 100us delay to synchronize the END_TRANSFER command completion
before giving back requests to the function drivers. Now, the controller
driver can handle cancelled TRBs with the requests' cancelled_list and
it can also wait until the END_TRANSFER completion before starting new
transfers. Synchronization can simply base on the controller's command
completion interrupt. The 100us delay is no longer needed. Remove this
arbitrary delay.

Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thinh Nguyen 2019-12-18 18:14:56 -08:00 committed by Greg Kroah-Hartman
parent da10bcdd6f
commit cf2f8b63f7
1 changed files with 5 additions and 13 deletions
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18
drivers/usb/dwc3/gadget.c
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@ -2693,7 +2693,6 @@ static void dwc3_reset_gadget(struct dwc3 *dwc)
static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
bool interrupt)
{
struct dwc3 *dwc = dep->dwc;
struct dwc3_gadget_ep_cmd_params params;
u32 cmd;
int ret;
@ -2709,16 +2708,13 @@ static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
* 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 arbitrary 100us delay for that.
* suggested to giveback all requests here.
*
* 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
* In short, what we're doing is issuing EndTransfer with
* CMDIOC bit set and delay kicking transfer until the
* EndTransfer command had completed.
*
* As of IP version 3.10a of the DWC_usb3 IP, the controller
* supports a mode to work around the above limitation. The
@ -2727,8 +2723,7 @@ static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
* by writing GUCTL2[14]. This polling is already done in the
* dwc3_send_gadget_ep_cmd() function so if the mode is
* enabled, the EndTransfer command will have completed upon
* returning from this function and we don't need to delay for
* 100us.
* returning from this function.
*
* This mode is NOT available on the DWC_usb31 IP.
*/
@ -2746,9 +2741,6 @@ static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
else
dep->flags |= DWC3_EP_END_TRANSFER_PENDING;
if (dwc3_is_usb31(dwc) || dwc->revision < DWC3_REVISION_310A)
udelay(100);
}
static void dwc3_clear_stall_all_ep(struct dwc3 *dwc)