From: Wesley Cheng quic_wcheng@quicinc.com
commit d8a2bb4eb75866275b5cf7de2e593ac3449643e2 upstream.
Previously, there was a 100uS delay inserted after issuing an end transfer command for specific controller revisions. This was due to the fact that there was a GUCTL2 bit field which enabled synchronous completion of the end transfer command once the CMDACT bit was cleared in the DEPCMD register. Since this bit does not exist for all controller revisions and the current implementation heavily relies on utizling the EndTransfer command completion interrupt, add the delay back in for uses where the interrupt on completion bit is not set, and increase the duration to 1ms for the controller to complete the command.
An issue was seen where the USB request buffer was unmapped while the DWC3 controller was still accessing the TRB. However, it was confirmed that the end transfer command was successfully submitted. (no end transfer timeout) In situations, such as dwc3_gadget_soft_disconnect() and __dwc3_gadget_ep_disable(), the dwc3_remove_request() is utilized, which will issue the end transfer command, and follow up with dwc3_gadget_giveback(). At least for the USB ep disable path, it is required for any pending and started requests to be completed and returned to the function driver in the same context of the disable call. Without the GUCTL2 bit, it is not ensured that the end transfer is completed before the buffers are unmapped.
Fixes: cf2f8b63f7f1 ("usb: dwc3: gadget: Remove END_TRANSFER delay") Cc: stable stable@kernel.org Signed-off-by: Wesley Cheng quic_wcheng@quicinc.com Acked-by: Thinh Nguyen Thinh.Nguyen@synopsys.com Link: https://lore.kernel.org/r/20230306200557.29387-1-quic_wcheng@quicinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/dwc3/gadget.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)
--- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -1689,6 +1689,7 @@ static int __dwc3_gadget_get_frame(struc */ static int __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; @@ -1712,10 +1713,13 @@ static int __dwc3_stop_active_transfer(s WARN_ON_ONCE(ret); dep->resource_index = 0;
- if (!interrupt) + if (!interrupt) { + if (!DWC3_IP_IS(DWC3) || DWC3_VER_IS_PRIOR(DWC3, 310A)) + mdelay(1); dep->flags &= ~DWC3_EP_TRANSFER_STARTED; - else if (!ret) + } else if (!ret) { dep->flags |= DWC3_EP_END_TRANSFER_PENDING; + }
dep->flags &= ~DWC3_EP_DELAY_STOP; return ret; @@ -3764,7 +3768,11 @@ void dwc3_stop_active_transfer(struct dw * enabled, the EndTransfer command will have completed upon * returning from this function. * - * This mode is NOT available on the DWC_usb31 IP. + * This mode is NOT available on the DWC_usb31 IP. In this + * case, if the IOC bit is not set, then delay by 1ms + * after issuing the EndTransfer command. This allows for the + * controller to handle the command completely before DWC3 + * remove requests attempts to unmap USB request buffers. */
__dwc3_stop_active_transfer(dep, force, interrupt);