[PATCH AUTOSEL 4.19 032/100] usb: dwc3: gadget: clear DWC3_EP_TRANSFER_STARTED on cmd complete

[Sasha Levin]

From: Felipe Balbi <felipe.ba...@linux.intel.com>

[ Upstream commit acbfa6c26f21a18830ee064b588c92334305b6af ]

We must wait until End Transfer completes in order to clear
DWC3_EP_TRANSFER_STARTED, otherwise we may confuse the driver.

This patch is in preparation to fix a rare race condition that happens
upon Disconnect Interrupt.

Tested-by: Thinh Nguyen <thi...@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.ba...@linux.intel.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/usb/dwc3/gadget.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 7b0957c530485..54de732550648 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -375,19 +375,9 @@ int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned 
cmd,
 
        trace_dwc3_gadget_ep_cmd(dep, cmd, params, cmd_status);
 
-       if (ret == 0) {
-               switch (DWC3_DEPCMD_CMD(cmd)) {
-               case DWC3_DEPCMD_STARTTRANSFER:
-                       dep->flags |= DWC3_EP_TRANSFER_STARTED;
-                       dwc3_gadget_ep_get_transfer_index(dep);
-                       break;
-               case DWC3_DEPCMD_ENDTRANSFER:
-                       dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
-                       break;
-               default:
-                       /* nothing */
-                       break;
-               }
+       if (ret == 0 && DWC3_DEPCMD_CMD(cmd) == DWC3_DEPCMD_STARTTRANSFER) {
+               dep->flags |= DWC3_EP_TRANSFER_STARTED;
+               dwc3_gadget_ep_get_transfer_index(dep);
        }
 
        if (unlikely(susphy)) {
@@ -2417,7 +2407,8 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
                cmd = DEPEVT_PARAMETER_CMD(event->parameters);
 
                if (cmd == DWC3_DEPCMD_ENDTRANSFER) {
-                       dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING;
+                       dep->flags &= ~(DWC3_EP_END_TRANSFER_PENDING |
+                                       DWC3_EP_TRANSFER_STARTED);
                        dwc3_gadget_ep_cleanup_cancelled_requests(dep);
                }
                break;
-- 
2.20.1