MdeModulePkg/XhciDxe:1ms delay before access MMIO reg during reset

Some XHCI host controllers require to have extra 1ms delay before
accessing any MMIO register during HC reset.

As this delay is not defined by XHCI spec, we use this workaround
to fix the issue.

Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>

diff --git a/MdeModulePkg/Bus/Pci/XhciDxe/XhciReg.c b/MdeModulePkg/Bus/Pci/XhciDxe/XhciReg.c
index d0f22050addb07817c06e3b75bc378dea9d52c6d..0e1c86cc16f4b7f2464b3e2e69bc44842c353713 100644 (file)
--- a/MdeModulePkg/Bus/Pci/XhciDxe/XhciReg.c
+++ b/MdeModulePkg/Bus/Pci/XhciDxe/XhciReg.c
@@ -2,7 +2,7 @@
 \r
   The XHCI register operation routines.\r
 \r
-Copyright (c) 2011 - 2015, Intel Corporation. All rights reserved.<BR>\r
+Copyright (c) 2011 - 2016, Intel Corporation. All rights reserved.<BR>\r
 This program and the accompanying materials\r
 are licensed and made available under the terms and conditions of the BSD License\r
 which accompanies this distribution.  The full text of the license may be found at\r
@@ -687,6 +687,12 @@ XhcResetHC (
   if ((Xhc->DebugCapSupOffset == 0xFFFFFFFF) || ((XhcReadExtCapReg (Xhc, Xhc->DebugCapSupOffset) & 0xFF) != XHC_CAP_USB_DEBUG) ||\r
       ((XhcReadExtCapReg (Xhc, Xhc->DebugCapSupOffset + XHC_DC_DCCTRL) & BIT0) == 0)) {\r
     XhcSetOpRegBit (Xhc, XHC_USBCMD_OFFSET, XHC_USBCMD_RESET);\r
+    //\r
+    // Some XHCI host controllers require to have extra 1ms delay before accessing any MMIO register during reset.\r
+    // Otherwise there may have the timeout case happened.\r
+    // The below is a workaround to solve such problem.\r
+    //\r
+    gBS->Stall (XHC_1_MILLISECOND);\r
     Status = XhcWaitOpRegBit (Xhc, XHC_USBCMD_OFFSET, XHC_USBCMD_RESET, FALSE, Timeout);\r
   }\r
 \r