Fixed unexpected timeout in Usb MassStorage Driver.

Fixed unexpected timeout in Uhci/Ehci driver.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@4038 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/Bus/Pci/EhciDxe/Ehci.c

@@ -126,7 +126,7 @@ EhcReset (
     // Host Controller must be Halt when Reset it
     //
     if (!EhcIsHalt (Ehc)) {
-      Status = EhcHaltHC (Ehc, EHC_GENERIC_TIME);
+      Status = EhcHaltHC (Ehc, EHC_GENERIC_TIMEOUT);
 
       if (EFI_ERROR (Status)) {
         Status = EFI_DEVICE_ERROR;
@@ -142,7 +142,7 @@ EhcReset (
     EhcAckAllInterrupt (Ehc);
     EhcFreeSched (Ehc);
 
-    Status = EhcResetHC (Ehc, EHC_STALL_1_SECOND);
+    Status = EhcResetHC (Ehc, EHC_RESET_TIMEOUT);
 
     if (EFI_ERROR (Status)) {
       goto ON_EXIT;
@@ -251,7 +251,7 @@ EhcSetState (
 
   switch (State) {
   case EfiUsbHcStateHalt:
-    Status = EhcHaltHC (Ehc, EHC_GENERIC_TIME);
+    Status = EhcHaltHC (Ehc, EHC_GENERIC_TIMEOUT);
     break;
 
   case EfiUsbHcStateOperational:
@@ -260,7 +260,17 @@ EhcSetState (
       break;
     }
 
-    Status = EhcRunHC (Ehc, EHC_GENERIC_TIME);
+    //
+    // Software must not write a one to this field unless the host controller
+    // is in the Halted state. Doing so will yield undefined results. 
+    // refers to Spec[EHCI1.0-2.3.1]
+    // 
+    if (!EHC_REG_BIT_IS_SET (Ehc, EHC_USBSTS_OFFSET, USBSTS_HALT)) {
+      Status = EFI_DEVICE_ERROR;
+      break;
+    }
+
+    Status = EhcRunHC (Ehc, EHC_GENERIC_TIMEOUT);
     break;
 
   case EfiUsbHcStateSuspend:
@@ -437,7 +447,7 @@ EhcSetRootHubPortFeature (
     // Make sure Host Controller not halt before reset it
     //
     if (EhcIsHalt (Ehc)) {
-      Status = EhcRunHC (Ehc, EHC_GENERIC_TIME);
+      Status = EhcRunHC (Ehc, EHC_GENERIC_TIMEOUT);
 
       if (EFI_ERROR (Status)) {
         EHC_DEBUG (("EhcSetRootHubPortFeature :failed to start HC - %r\n", Status));
@@ -1539,7 +1549,7 @@ EhcDriverBindingStart (
   // Robustnesss improvement such as for UoL
   //
   EhcClearLegacySupport (Ehc);
-  EhcResetHC (Ehc, EHC_STALL_1_SECOND);
+  EhcResetHC (Ehc, EHC_RESET_TIMEOUT);
 
   Status = EhcInitHC (Ehc);
 
@@ -1551,12 +1561,12 @@ EhcDriverBindingStart (
   //
   // Start the asynchronous interrupt monitor
   //
-  Status = gBS->SetTimer (Ehc->PollTimer, TimerPeriodic, EHC_ASYNC_POLL_TIME);
+  Status = gBS->SetTimer (Ehc->PollTimer, TimerPeriodic, EHC_ASYNC_POLL_INTERVAL);
 
   if (EFI_ERROR (Status)) {
     EHC_ERROR (("EhcDriverBindingStart: failed to start async interrupt monitor\n"));
 
-    EhcHaltHC (Ehc, EHC_GENERIC_TIME);
+    EhcHaltHC (Ehc, EHC_GENERIC_TIMEOUT);
     goto UNINSTALL_USBHC;
   }
 
@@ -1659,8 +1669,8 @@ EhcDriverBindingStop (
   // Stop AsyncRequest Polling timer then stop the EHCI driver
   // and uninstall the EHCI protocl.
   //
-  gBS->SetTimer (Ehc->PollTimer, TimerCancel, EHC_ASYNC_POLL_TIME);
+  gBS->SetTimer (Ehc->PollTimer, TimerCancel, EHC_ASYNC_POLL_INTERVAL);
-  EhcHaltHC (Ehc, EHC_GENERIC_TIME);
+  EhcHaltHC (Ehc, EHC_GENERIC_TIMEOUT);
 
   Status = gBS->UninstallProtocolInterface (
                   Controller,

MdeModulePkg/Bus/Pci/EhciDxe/Ehci.h

@@ -49,18 +49,35 @@ typedef struct _USB2_HC_DEV  USB2_HC_DEV;
 #include "EhciDebug.h"
 
 enum {
+  EHC_1_MICROSECOND            = 1,
+  EHC_1_MILLISECOND            = 1000 * EHC_1_MICROSECOND,
+  EHC_1_SECOND                 = 1000 * EHC_1_MILLISECOND,
+
+  //
+  // EHCI register operation timeout, set by experience
+  //
+  EHC_RESET_TIMEOUT            = 1 * EHC_1_SECOND,
+  EHC_GENERIC_TIMEOUT          = 10 * EHC_1_MILLISECOND,
+
+  //
+  // Wait for roothub port power stable, refers to Spec[EHCI1.0-2.3.9]
+  //
+  EHC_ROOT_PORT_RECOVERY_STALL = 20 * EHC_1_MILLISECOND,
+
+  //
+  // Sync and Async transfer polling interval, set by experience, 
+  // and the unit of Async is 100us, means 50ms as interval.
+  //
+  EHC_SYNC_POLL_INTERVAL       = 20 * EHC_1_MICROSECOND,
+  EHC_ASYNC_POLL_INTERVAL      = 50 * 10000U,                  
+
+  //
+  // EHC raises TPL to TPL_NOTIFY to serialize all its operations
+  // to protect shared data structures.
+  //
+  EHC_TPL                      = TPL_NOTIFY,
+
   USB2_HC_DEV_SIGNATURE        = EFI_SIGNATURE_32 ('e', 'h', 'c', 'i'),
-  EHC_STALL_1_MICROSECOND   = 1,
-  EHC_STALL_1_MILLISECOND   = 1000 * EHC_STALL_1_MICROSECOND,
-  EHC_STALL_1_SECOND        = 1000 * EHC_STALL_1_MILLISECOND,
-
-  EHC_SET_PORT_RESET_TIME   = 50 * EHC_STALL_1_MILLISECOND,
-  EHC_CLEAR_PORT_RESET_TIME = EHC_STALL_1_MILLISECOND,
-  EHC_GENERIC_TIME          = 10 * EHC_STALL_1_MILLISECOND,
-  EHC_SYNC_POLL_TIME        = 20 * EHC_STALL_1_MICROSECOND,
-  EHC_ASYNC_POLL_TIME       = 50 * 10000UL,                 // The unit of time is 100us
-
-  EHC_TPL                   = TPL_NOTIFY
 };
 
 //

MdeModulePkg/Bus/Pci/EhciDxe/EhciReg.c

@@ -214,12 +214,12 @@ EhcWaitOpRegBit (
 {
   UINT32                  Index;
 
-  for (Index = 0; Index < Timeout / EHC_SYNC_POLL_TIME + 1; Index++) {
+  for (Index = 0; Index < Timeout / EHC_SYNC_POLL_INTERVAL + 1; Index++) {
     if (EHC_REG_BIT_IS_SET (Ehc, Offset, Bit) == WaitToSet) {
       return EFI_SUCCESS;
     }
 
-    gBS->Stall (EHC_SYNC_POLL_TIME);
+    gBS->Stall (EHC_SYNC_POLL_INTERVAL);
   }
 
   return EFI_TIMEOUT;
@@ -614,14 +614,19 @@ EhcInitHC (
   //
   EhcSetOpRegBit (Ehc, EHC_CONFIG_FLAG_OFFSET, CONFIGFLAG_ROUTE_EHC);
 
-  Status = EhcEnablePeriodSchd (Ehc, EHC_GENERIC_TIME);
+  //
+  // Wait roothub port power stable
+  //
+  gBS->Stall (EHC_ROOT_PORT_RECOVERY_STALL);
+
+  Status = EhcEnablePeriodSchd (Ehc, EHC_GENERIC_TIMEOUT);
 
   if (EFI_ERROR (Status)) {
     EHC_ERROR (("EhcInitHC: failed to enable period schedule\n"));
     return Status;
   }
 
-  Status = EhcEnableAsyncSchd (Ehc, EHC_GENERIC_TIME);
+  Status = EhcEnableAsyncSchd (Ehc, EHC_GENERIC_TIMEOUT);
 
   if (EFI_ERROR (Status)) {
     EHC_ERROR (("EhcInitHC: failed to enable async schedule\n"));

MdeModulePkg/Bus/Pci/EhciDxe/EhciSched.c

@@ -342,7 +342,7 @@ EhcUnlinkQhFromAsync (
   //
   // Set and wait the door bell to synchronize with the hardware
   //
-  Status = EhcSetAndWaitDoorBell (Ehc, EHC_GENERIC_TIME);
+  Status = EhcSetAndWaitDoorBell (Ehc, EHC_GENERIC_TIMEOUT);
 
   if (EFI_ERROR (Status)) {
     EHC_ERROR (("EhcUnlinkQhFromAsync: Failed to synchronize with doorbell\n"));
@@ -659,7 +659,7 @@ EhcExecTransfer (
   BOOLEAN                 Finished;
 
   Status    = EFI_SUCCESS;
-  Loop      = (TimeOut * EHC_STALL_1_MILLISECOND / EHC_SYNC_POLL_TIME) + 1;
+  Loop      = (TimeOut * EHC_1_MILLISECOND / EHC_SYNC_POLL_INTERVAL) + 1;
   Finished  = FALSE;
 
   for (Index = 0; Index < Loop; Index++) {
@@ -669,7 +669,7 @@ EhcExecTransfer (
       break;
     }
 
-    gBS->Stall (EHC_SYNC_POLL_TIME);
+    gBS->Stall (EHC_SYNC_POLL_INTERVAL);
   }
 
   if (!Finished) {

MdeModulePkg/Bus/Pci/UhciDxe/Uhci.c

@@ -56,38 +56,27 @@ UhciReset (
     //
     // Stop schedule and set the Global Reset bit in the command register
     //
-    UhciStopHc (Uhc, STALL_1_SECOND);
+    UhciStopHc (Uhc, UHC_GENERIC_TIMEOUT);
     UhciSetRegBit (Uhc->PciIo, USBCMD_OFFSET, USBCMD_GRESET);
 
-    //
+    gBS->Stall (UHC_ROOT_PORT_RESET_STALL);
-    // Wait 50ms for root port to let reset complete
-    // See UHCI spec page122 Reset signaling
-    //
-    gBS->Stall (ROOT_PORT_REST_TIME);
 
     //
     // Clear the Global Reset bit to zero.
     //
     UhciClearRegBit (Uhc->PciIo, USBCMD_OFFSET, USBCMD_GRESET);
 
-    //
+    gBS->Stall (UHC_ROOT_PORT_RECOVERY_STALL);
-    // UHCI spec page120 reset recovery time
-    //
-    gBS->Stall (PORT_RESET_RECOVERY_TIME);
     break;
 
   case EFI_USB_HC_RESET_HOST_CONTROLLER:
     //
     // Stop schedule and set Host Controller Reset bit to 1
     //
-    UhciStopHc (Uhc, STALL_1_SECOND);
+    UhciStopHc (Uhc, UHC_GENERIC_TIMEOUT);
     UhciSetRegBit (Uhc->PciIo, USBCMD_OFFSET, USBCMD_HCRESET);
 
-    //
+    gBS->Stall (UHC_ROOT_PORT_RECOVERY_STALL);
-    // this bit will be reset by Host Controller when reset is completed.
-    // wait 10ms to let reset complete
-    //
-    gBS->Stall (PORT_RESET_RECOVERY_TIME);
     break;
 
   default:
@@ -202,7 +191,7 @@ UhciSetState (
 
   switch (State) {
   case EfiUsbHcStateHalt:
-    Status = UhciStopHc (Uhc, STALL_1_SECOND);
+    Status = UhciStopHc (Uhc, UHC_GENERIC_TIMEOUT);
     break;
 
   case EfiUsbHcStateOperational:
@@ -228,7 +217,7 @@ UhciSetState (
       //
       // wait 20ms to let resume complete (20ms is specified by UHCI spec)
       //
-      gBS->Stall (FORCE_GLOBAL_RESUME_TIME);
+      gBS->Stall (UHC_FORCE_GLOBAL_RESUME_STALL);
 
       //
       // Write FGR bit to 0 and EGSM(Enter Global Suspend Mode) bit to 0
@@ -2084,7 +2073,7 @@ UhciCleanDevUp (
   // Uninstall the USB_HC and USB_HC2 protocol, then disable the controller
   //
   Uhc = UHC_FROM_USB_HC_PROTO (This);
-  UhciStopHc (Uhc, STALL_1_SECOND);
+  UhciStopHc (Uhc, UHC_GENERIC_TIMEOUT);
 
   gBS->UninstallProtocolInterface (
         Controller,
@@ -2188,7 +2177,7 @@ UhciDriverBindingStart (
   Status = gBS->SetTimer (
                   Uhc->AsyncIntMonitor,
                   TimerPeriodic,
-                  INTERRUPT_POLLING_TIME
+                  UHC_ASYNC_POLL_INTERVAL
                   );
 
   if (EFI_ERROR (Status)) {

MdeModulePkg/Bus/Pci/UhciDxe/Uhci.h

@@ -51,17 +51,35 @@ typedef struct _USB_HC_DEV  USB_HC_DEV;
 #include "UhciDebug.h"
 
 enum {
-  //
+  UHC_1_MICROSECOND             = 1,
-  // Stall times
+  UHC_1_MILLISECOND             = 1000 * UHC_1_MICROSECOND,
-  //
+  UHC_1_SECOND                  = 1000 * UHC_1_MILLISECOND,
-  STALL_1_MS               = 1000,
-  STALL_1_SECOND           = 1000 *STALL_1_MS,
 
-  UHC_SYN_POLL             = 50,
+  //
-  FORCE_GLOBAL_RESUME_TIME = 20 *STALL_1_MS,
+  // UHCI register operation timeout, set by experience
-  ROOT_PORT_REST_TIME      = 50 *STALL_1_MS,
+  //
-  PORT_RESET_RECOVERY_TIME = 10 *STALL_1_MS,
+  UHC_GENERIC_TIMEOUT           = UHC_1_SECOND,
-  INTERRUPT_POLLING_TIME   = 50 * 10000UL,
+  
+  //
+  // Wait for force global resume(FGR) complete, refers to
+  // specification[UHCI11-2.1.1]
+  // 
+  UHC_FORCE_GLOBAL_RESUME_STALL = 20 * UHC_1_MILLISECOND,
+
+  //
+  // Wait for roothub port reset and recovery, reset stall
+  // is set by experience, and recovery stall refers to 
+  // specification[UHCI11-2.1.1]
+  //
+  UHC_ROOT_PORT_RESET_STALL     = 50 * UHC_1_MILLISECOND,
+  UHC_ROOT_PORT_RECOVERY_STALL  = 10 * UHC_1_MILLISECOND,
+
+  //
+  // Sync and Async transfer polling interval, set by experience, 
+  // and the unit of Async is 100us.
+  //
+  UHC_SYNC_POLL_INTERVAL        = 50 * UHC_1_MICROSECOND,
+  UHC_ASYNC_POLL_INTERVAL       = 50 * 10000UL,
   
   //
   // UHC raises TPL to TPL_NOTIFY to serialize all its operations
@@ -69,7 +87,7 @@ enum {
   //
   UHCI_TPL                 = TPL_NOTIFY,
 
-  USB_HC_DEV_SIGNATURE     = EFI_SIGNATURE_32 ('u', 'h', 'c', 'i')
+  USB_HC_DEV_SIGNATURE          = EFI_SIGNATURE_32 ('u', 'h', 'c', 'i'),
 };
 
 #pragma pack(1)

MdeModulePkg/Bus/Pci/UhciDxe/UhciSched.c

@@ -575,7 +575,7 @@ UhciExecuteTransfer (
 
   Finished = FALSE;
   Status   = EFI_SUCCESS;
-  Delay    = (TimeOut * STALL_1_MS / UHC_SYN_POLL) + 1;
+  Delay    = (TimeOut * UHC_1_MILLISECOND / UHC_SYNC_POLL_INTERVAL) + 1;
   
   for (Index = 0; Index < Delay; Index++) {
     Finished = UhciCheckTdStatus (Uhc, Td, IsLow, QhResult);
@@ -587,7 +587,7 @@ UhciExecuteTransfer (
       break;
     }
 
-    gBS->Stall (UHC_SYN_POLL);
+    gBS->Stall (UHC_SYNC_POLL_INTERVAL);
   }
 
   if (!Finished) {

MdeModulePkg/Bus/Usb/UsbBusDxe/UsbDesc.c

@@ -464,7 +464,7 @@ UsbCtrlRequest (
              Direction,
              Buf,
              &Len,
-             50 * USB_STALL_1_MS,
+             USB_GENERAL_DEVICE_REQUEST_TIMEOUT,
              &UsbDev->Translator,
              &Result
              );
@@ -554,7 +554,7 @@ UsbGetMaxPacketSize0 (
       return EFI_SUCCESS;
     }
 
-    gBS->Stall (100 * USB_STALL_1_MS);
+    gBS->Stall (USB_RETRY_MAX_PACK_SIZE_STALL);
   }
 
   return EFI_DEVICE_ERROR;
@@ -981,7 +981,7 @@ UsbIoClearFeature (
                     UsbIo,
                     &DevReq,
                     EfiUsbNoData,
-                    10 * USB_STALL_1_MS,
+                    USB_CLEAR_FEATURE_REQUEST_TIMEOUT,
                     NULL,
                     0,
                     &UsbResult

MdeModulePkg/Bus/Usb/UsbBusDxe/UsbEnumer.c

@@ -657,11 +657,7 @@ UsbEnumerateNewDev (
   Bus     = Parent->Bus;
   HubApi  = HubIf->HubApi;
   
-
+  gBS->Stall (USB_WAIT_PORT_STABLE_STALL);
-  //
-  // Wait at least 100 ms for the power on port to stable
-  //
-  gBS->Stall (100 * USB_STALL_1_MS);
   
   //
   // Hub resets the device for at least 10 milliseconds.
@@ -775,10 +771,7 @@ UsbEnumerateNewDev (
     goto ON_ERROR;
   }
   
-  //
+  gBS->Stall (USB_SET_DEVICE_ADDRESS_STALL);
-  // Wait 20ms for set address to complete
-  //
-  gBS->Stall (20 * USB_STALL_1_MS);
 
   DEBUG ((EFI_D_INFO, "UsbEnumerateNewDev: device is now ADDRESSED at %d\n", Address));
 
@@ -886,6 +879,7 @@ UsbEnumeratePort (
 
     if (USB_BIT_IS_SET (PortState.PortStatus, USB_PORT_STAT_OVERCURRENT)) {
       //
+      // Case1:
       //   Both OverCurrent and OverCurrentChange set, means over current occurs, 
       //   which probably is caused by short circuit. It has to wait system hardware
       //   to perform recovery.
@@ -893,40 +887,36 @@ UsbEnumeratePort (
       DEBUG (( EFI_D_ERROR, "UsbEnumeratePort: Critical Over Current\n", Port));
       return EFI_DEVICE_ERROR;
       
-    } else {
+    } 
     //
+    // Case2:
     //   Only OverCurrentChange set, means system has been recoveried from 
     //   over current. As a result, all ports are nearly power-off, so
     //   it's necessary to detach and enumerate all ports again. 
     //
     DEBUG (( EFI_D_ERROR, "UsbEnumeratePort: 2.0 device Recovery Over Current\n", Port)); 
-      goto ON_ENUMERATE;
-      
-    }
   }
 
   if (USB_BIT_IS_SET (PortState.PortChangeStatus, USB_PORT_STAT_C_ENABLE)) {  
     //
+    // Case3:
     //   1.1 roothub port reg doesn't reflect over-current state, while its counterpart
     //   on 2.0 roothub does. When over-current has influence on 1.1 device, the port 
     //   would be disabled, so it's also necessary to detach and enumerate again.
     //
     DEBUG (( EFI_D_ERROR, "UsbEnumeratePort: 1.1 device Recovery Over Current\n", Port));
-    goto ON_ENUMERATE;
   }
   
   if (USB_BIT_IS_SET (PortState.PortChangeStatus, USB_PORT_STAT_C_CONNECTION)) {
     //
+    // Case4:
     //   Device connected or disconnected normally. 
     //
-    goto ON_ENUMERATE;
+    DEBUG ((EFI_D_ERROR, "UsbEnumeratePort: Device Connect/Discount Normally\n", Port));
   }
 
-ON_ENUMERATE:
-
   // 
-  // In case there is already a device on this port logically, it's safety to remove
+  // Following as the above cases, it's safety to remove and create again.
-  // and enumerate again.
   //
   Child = UsbFindChild (HubIf, Port);
   

MdeModulePkg/Bus/Usb/UsbBusDxe/UsbHub.c

@@ -745,7 +745,7 @@ UsbHubInit (
     UsbHubCtrlSetPortFeature (HubIf->Device, Index, (EFI_USB_PORT_FEATURE) USB_HUB_PORT_POWER);
   }
 
-  gBS->Stall (HubDesc.PwrOn2PwrGood * 2 * USB_STALL_1_MS);
+  gBS->Stall (HubDesc.PwrOn2PwrGood * USB_SET_PORT_POWER_STALL);
   UsbHubAckHubStatus (HubIf->Device);
 
   DEBUG (( EFI_D_INFO, "UsbHubInit: hub %d initialized\n", HubDev->Address));
@@ -915,14 +915,14 @@ UsbHubResetPort (
   // Drive the reset signal for at least 10ms. Check USB 2.0 Spec
   // section 7.1.7.5 for timing requirements.
   //
-  gBS->Stall (20 * USB_STALL_1_MS);
+  gBS->Stall (USB_SET_PORT_RESET_STALL);
 
   //
   // USB hub will clear RESET bit if reset is actually finished.
   //
   ZeroMem (&PortState, sizeof (EFI_USB_PORT_STATUS));
 
-  for (Index = 0; Index < 20; Index++) {
+  for (Index = 0; Index < USB_WAIT_PORT_STS_CHANGE_LOOP; Index++) {
     Status = UsbHubGetPortStatus (HubIf, Port, &PortState);
 
     if (!EFI_ERROR (Status) &&
@@ -931,7 +931,7 @@ UsbHubResetPort (
       return EFI_SUCCESS;
     }
 
-    gBS->Stall (5 * USB_STALL_1_MS);
+    gBS->Stall (USB_WAIT_PORT_STS_CHANGE_STALL);
   }
 
   return EFI_TIMEOUT;
@@ -1228,7 +1228,7 @@ UsbRootHubResetPort (
   // Drive the reset signal for at least 50ms. Check USB 2.0 Spec
   // section 7.1.7.5 for timing requirements.
   //
-  gBS->Stall (50 * USB_STALL_1_MS);
+  gBS->Stall (USB_SET_ROOT_PORT_RESET_STALL);
 
   Status = UsbHcClearRootHubPortFeature (Bus, Port, EfiUsbPortReset);
 
@@ -1237,7 +1237,7 @@ UsbRootHubResetPort (
     return Status;
   }
 
-  gBS->Stall (USB_STALL_1_MS);
+  gBS->Stall (USB_CLR_ROOT_PORT_RESET_STALL);
 
   //
   // USB host controller won't clear the RESET bit until
@@ -1245,7 +1245,7 @@ UsbRootHubResetPort (
   //
   ZeroMem (&PortState, sizeof (EFI_USB_PORT_STATUS));
 
-  for (Index = 0; Index < USB_HUB_LOOP; Index++) {
+  for (Index = 0; Index < USB_WAIT_PORT_STS_CHANGE_LOOP; Index++) {
     Status = UsbHcGetRootHubPortStatus (Bus, Port, &PortState);
 
     if (EFI_ERROR (Status)) {
@@ -1256,10 +1256,10 @@ UsbRootHubResetPort (
       break;
     }
 
-    gBS->Stall (10 * USB_STALL_1_MS);
+    gBS->Stall (USB_WAIT_PORT_STS_CHANGE_STALL);
   }
 
-  if (Index == USB_HUB_LOOP) {
+  if (Index == USB_WAIT_PORT_STS_CHANGE_LOOP) {
     DEBUG ((EFI_D_ERROR, "UsbRootHubResetPort: reset not finished in time on port %d\n", Port));
     return EFI_TIMEOUT;
   }
@@ -1286,7 +1286,7 @@ UsbRootHubResetPort (
         return Status;
       }
 
-      gBS->Stall (20 * USB_STALL_1_MS);
+      gBS->Stall (USB_SET_ROOT_PORT_ENABLE_STALL);
     }
   }
 

MdeModulePkg/Bus/Usb/UsbBusDxe/UsbHub.h

@@ -90,8 +90,11 @@ enum {
   USB_HUB_CLASS_CODE          = 0x09,
   USB_HUB_SUBCLASS_CODE       = 0x00,
 
-
+  //
-  USB_HUB_LOOP                = 50
+  // Host software return timeout if port status doesn't change 
+  // after 500ms(LOOP * STALL = 100 * 5ms), set by experience
+  //
+  USB_WAIT_PORT_STS_CHANGE_LOOP   = 100,
 };
 
 #pragma pack(1)
@@ -112,7 +115,7 @@ typedef struct {
 
 typedef struct {
   UINT16                ChangedBit;
-  UINT8                 Feature;
+  EFI_USB_PORT_FEATURE  Feature;
 } USB_CHANGE_FEATURE_MAP;
 
 

MdeModulePkg/Bus/Usb/UsbBusDxe/usbbus.c

@@ -1142,44 +1142,9 @@ UsbBusControllerDriverStart (
     goto CLOSE_HC;
   }
 
-  //
-  // Create a fake usb device for root hub
-  //
-  RootHub = AllocateZeroPool (sizeof (USB_DEVICE));
-
-  if (RootHub == NULL) {
-    Status = EFI_OUT_OF_RESOURCES;
-    goto CLOSE_HC;
-  }
-
-  RootIf = AllocateZeroPool (sizeof (USB_INTERFACE));
-
-  if (RootIf == NULL) {
-    gBS->FreePool (RootHub);
-    Status = EFI_OUT_OF_RESOURCES;
-    goto CLOSE_HC;
-  }
-
-  RootHub->Bus            = UsbBus;
-  RootHub->NumOfInterface = 1;
-  RootHub->Interfaces[0]  = RootIf;
-  RootIf->Signature       = USB_INTERFACE_SIGNATURE;
-  RootIf->Device          = RootHub;
-  RootIf->DevicePath      = UsbBus->DevicePath;
-
-  
   UsbHcReset (UsbBus, EFI_USB_HC_RESET_GLOBAL);
   UsbHcSetState (UsbBus, EfiUsbHcStateOperational);
 
-  Status                  = mUsbRootHubApi.Init (RootIf);
-
-  if (EFI_ERROR (Status)) {
-    DEBUG (( EFI_D_ERROR, "UsbBusStart: Failed to init root hub %r\n", Status));
-    goto FREE_ROOTHUB;
-  }
-
-  UsbBus->Devices[0] = RootHub;
-
   //
   // Install an EFI_USB_BUS_PROTOCOL to host controler to identify it.
   //
@@ -1192,18 +1157,56 @@ UsbBusControllerDriverStart (
 
   if (EFI_ERROR (Status)) {
     DEBUG ((EFI_D_ERROR, "UsbBusStart: Failed to install bus protocol %r\n", Status));
+    goto CLOSE_HC;
+  }
 
-    mUsbRootHubApi.Release (RootIf);
+  //
+  // Create a fake usb device for root hub
+  //
+  RootHub = AllocateZeroPool (sizeof (USB_DEVICE));
+
+  if (RootHub == NULL) {
+    Status = EFI_OUT_OF_RESOURCES;
+    goto UNINSTALL_USBBUS;
+  }
+
+  RootIf = AllocateZeroPool (sizeof (USB_INTERFACE));
+
+  if (RootIf == NULL) {
+    gBS->FreePool (RootHub);
+    Status = EFI_OUT_OF_RESOURCES;
     goto FREE_ROOTHUB;
   }
 
+  RootHub->Bus            = UsbBus;
+  RootHub->NumOfInterface = 1;
+  RootHub->Interfaces[0]  = RootIf;
+  RootIf->Signature       = USB_INTERFACE_SIGNATURE;
+  RootIf->Device          = RootHub;
+  RootIf->DevicePath      = UsbBus->DevicePath;
+  
+  Status                  = mUsbRootHubApi.Init (RootIf);
+
+  if (EFI_ERROR (Status)) {
+    DEBUG (( EFI_D_ERROR, "UsbBusStart: Failed to init root hub %r\n", Status));
+    goto FREE_ROOTHUB;
+  }
+
+  UsbBus->Devices[0] = RootHub;
 
   DEBUG (( EFI_D_INFO, "UsbBusStart: usb bus started on %x, root hub %x\n", Controller, RootIf));
   return EFI_SUCCESS;
   
 FREE_ROOTHUB:
+  if (RootIf != NULL) {
     gBS->FreePool (RootIf);
+  }
+  if (RootHub != NULL) {
     gBS->FreePool (RootHub);
+  }
+  
+UNINSTALL_USBBUS:
+  gBS->UninstallProtocolInterface (Controller, &mUsbBusProtocolGuid, &UsbBus->BusId);
   
 CLOSE_HC:
   if (UsbBus->Usb2Hc != NULL) {
@@ -1214,7 +1217,6 @@ CLOSE_HC:
           Controller
           );
   }
-
   if (UsbBus->UsbHc != NULL) {
     gBS->CloseProtocol (
           Controller,
@@ -1223,14 +1225,12 @@ CLOSE_HC:
           Controller
           );
   }
-
   gBS->CloseProtocol (
          Controller,
          &gEfiDevicePathProtocolGuid,
          This->DriverBindingHandle,
          Controller
          );
-
   gBS->FreePool (UsbBus);
 
   DEBUG (( EFI_D_ERROR, "UsbBusStart: Failed to start bus driver %r\n", Status));

MdeModulePkg/Bus/Usb/UsbBusDxe/usbbus.h

@@ -55,21 +55,77 @@ typedef struct _USB_HUB_API    USB_HUB_API;
 #include "UsbEnumer.h"
 
 enum {
-  //
-  // Time definition
-  //
-  USB_STALL_1_MS            = 1000,
-  TICKS_PER_MS              = 10000U,
-  USB_ROOTHUB_POLL_INTERVAL = 1000 * TICKS_PER_MS,
-  USB_HUB_POLL_INTERVAL     = 64,
-
-  //
-  // Maximum definition
-  //
   USB_MAX_LANG_ID           = 16,
   USB_MAX_INTERFACE         = 16,
   USB_MAX_DEVICES           = 128,
 
+  USB_BUS_1_MILLISECOND     = 1000,
+
+  //
+  // Roothub and hub's polling interval, set by experience,
+  // The unit of roothub is 100us, means 1s as interval, and
+  // the unit of hub is 1ms, means 64ms as interval.
+  //
+  USB_ROOTHUB_POLL_INTERVAL = 1000 * 10000U,
+  USB_HUB_POLL_INTERVAL     = 64,
+
+  //
+  // Wait for port stable to work, refers to specification
+  // [USB20-9.1.2]
+  //
+  USB_WAIT_PORT_STABLE_STALL     = 100 * USB_BUS_1_MILLISECOND,
+
+  // 
+  // Wait for port statue reg change, set by experience
+  //
+  USB_WAIT_PORT_STS_CHANGE_STALL = 5 * USB_BUS_1_MILLISECOND,
+
+  //
+  // Wait for set device address, refers to specification
+  // [USB20-9.2.6.3, it says 2ms]
+  //
+  USB_SET_DEVICE_ADDRESS_STALL   = 20 * USB_BUS_1_MILLISECOND,
+
+  //
+  // Wait for retry max packet size, set by experience
+  //
+  USB_RETRY_MAX_PACK_SIZE_STALL  = 100 * USB_BUS_1_MILLISECOND,
+
+  //
+  // Wait for hub port power-on, refers to specification
+  // [USB20-11.23.2]
+  //
+  USB_SET_PORT_POWER_STALL       = 2 * USB_BUS_1_MILLISECOND,
+
+  //
+  // Wait for port reset, refers to specification 
+  // [USB20-7.1.7.5, it says 10ms for hub and 50ms for 
+  // root hub]
+  //
+  USB_SET_PORT_RESET_STALL       = 20 * USB_BUS_1_MILLISECOND,
+  USB_SET_ROOT_PORT_RESET_STALL  = 50 * USB_BUS_1_MILLISECOND,
+
+  //
+  // Wait for clear roothub port reset, set by experience
+  //
+  USB_CLR_ROOT_PORT_RESET_STALL  = 1 * USB_BUS_1_MILLISECOND,
+
+  //
+  // Wait for set roothub port enable, set by experience
+  // 
+  USB_SET_ROOT_PORT_ENABLE_STALL = 20 * USB_BUS_1_MILLISECOND,
+
+  //
+  // Send general device request timeout, refers to 
+  // specification[USB20-11.24.1]
+  //
+  USB_GENERAL_DEVICE_REQUEST_TIMEOUT = 50 * USB_BUS_1_MILLISECOND,
+
+  //
+  // Send clear feature request timeout, set by experience
+  //
+  USB_CLEAR_FEATURE_REQUEST_TIMEOUT  = 10 * USB_BUS_1_MILLISECOND,
+  
   //
   // Bus raises TPL to TPL_NOTIFY to serialize all its operations
   // to protect shared data structures.

MdeModulePkg/Bus/Usb/UsbMassStorageDxe/UsbMass.h

@@ -73,8 +73,8 @@ enum {
   USB_MASS_STORE_CBI1     = 0x01, // CBI protocol without command completion interrupt
   USB_MASS_STORE_BOT      = 0x50, // Bulk-Only Transport
 
-  USB_MASS_STALL_1_MS     = 1000,
+  USB_MASS_1_MILLISECOND  = 1000,
-  USB_MASS_STALL_1_S      = 1000 * USB_MASS_STALL_1_MS,
+  USB_MASS_1_SECOND       = 1000 * USB_MASS_1_MILLISECOND,
 
   USB_MASS_CMD_SUCCESS    = 0,
   USB_MASS_CMD_FAIL,

MdeModulePkg/Bus/Usb/UsbMassStorageDxe/UsbMassBoot.c

@@ -935,7 +935,7 @@ UsbClearEndpointStall (
   Request.Value       = USB_FEATURE_ENDPOINT_HALT;
   Request.Index       = EndpointAddr;
   Request.Length      = 0;
-  Timeout             = USB_BOOT_GENERAL_CMD_TIMEOUT / USB_MASS_STALL_1_MS;
+  Timeout             = USB_BOOT_GENERAL_CMD_TIMEOUT / USB_MASS_1_MILLISECOND;
 
   Status = UsbIo->UsbControlTransfer (
                     UsbIo,

MdeModulePkg/Bus/Usb/UsbMassStorageDxe/UsbMassBoot.h

@@ -38,7 +38,6 @@ enum {
   //
   USB_BOOT_INQUIRY_OPCODE         = 0x12,
   USB_BOOT_REQUEST_SENSE_OPCODE   = 0x03,
-
   USB_BOOT_MODE_SENSE10_OPCODE    = 0x5A,
   USB_BOOT_READ_CAPACITY_OPCODE   = 0x25,
   USB_BOOT_TEST_UNIT_READY_OPCODE = 0x00,
@@ -70,38 +69,38 @@ enum {
   USB_BOOT_ASC_MEDIA_CHANGE       = 0x28,
 
   //
-  // Other parameters
+  // Supported PDT codes, or Peripheral Device Type
   //
-  USB_BOOT_IO_BLOCKS              = 64,
+  USB_PDT_DIRECT_ACCESS           = 0x00,       // Direct access device
+  USB_PDT_CDROM                   = 0x05,       // CDROM
+  USB_PDT_OPTICAL                 = 0x07,       // Non-CD optical disks
+  USB_PDT_SIMPLE_DIRECT           = 0x0E,       // Simplified direct access device
   
   //
-  // Boot Retry times
+  // Other parameters, Max carried size is 512B * 128 = 64KB
+  //
+  USB_BOOT_IO_BLOCKS              = 128,
+
+  //
+  // Retry mass command times, set by experience
   //
   USB_BOOT_COMMAND_RETRY          = 5,
-  USB_BOOT_WAIT_RETRY             = 5,
+  USB_BOOT_INIT_MEDIA_RETRY       = 5,
 
   //
-  // Boot Stall time
+  // Wait for unit ready command, set by experience
   //
-  USB_BOOT_UNIT_READY_STALL       = 50 * USB_MASS_STALL_1_MS,
+  USB_BOOT_RETRY_UNIT_READY_STALL = 500 * USB_MASS_1_MILLISECOND,
 
   //
-  // Boot Transfer timeout
+  // Mass command timeout, refers to specification[USB20-9.2.6.1]
   //
   // USB2.0 Spec define the up-limit timeout 5s for all command. USB floppy, 
   // USB CD-Rom and iPod devices are much slower than USB key when reponse 
   // most of commands, So we set 5s as timeout here.
   // 
   //
-  USB_BOOT_GENERAL_CMD_TIMEOUT    = 5 * USB_MASS_STALL_1_S,
+  USB_BOOT_GENERAL_CMD_TIMEOUT    = 5 * USB_MASS_1_SECOND,
-  
-  //
-  // Supported PDT codes, or Peripheral Device Type
-  //
-  USB_PDT_DIRECT_ACCESS           = 0x00,       // Direct access device
-  USB_PDT_CDROM                   = 0x05,       // CDROM
-  USB_PDT_OPTICAL                 = 0x07,       // Non-CD optical disks
-  USB_PDT_SIMPLE_DIRECT           = 0x0E        // Simplified direct access device
 };
 
 //

MdeModulePkg/Bus/Usb/UsbMassStorageDxe/UsbMassBot.c

@@ -191,7 +191,7 @@ UsbBotSendCommand (
 
   Result        = 0;
   DataLen       = sizeof (USB_BOT_CBW);
-  Timeout       = USB_BOT_CBW_TIMEOUT / USB_MASS_STALL_1_MS;
+  Timeout       = USB_BOT_SEND_CBW_TIMEOUT / USB_MASS_1_MILLISECOND;
 
   //
   // Use the UsbIo to send the command to the device. The default
@@ -266,7 +266,7 @@ UsbBotDataTransfer (
   }
 
   Result  = 0;
-  Timeout = Timeout / USB_MASS_STALL_1_MS;
+  Timeout = Timeout / USB_MASS_1_MILLISECOND;
 
   Status = UsbBot->UsbIo->UsbBulkTransfer (
                             UsbBot->UsbIo,
@@ -328,9 +328,9 @@ UsbBotGetStatus (
   Status     = EFI_DEVICE_ERROR;
   Endpoint   = UsbBot->BulkInEndpoint->EndpointAddress;
   UsbIo      = UsbBot->UsbIo;
-  Timeout    = USB_BOT_CSW_TIMEOUT / USB_MASS_STALL_1_MS;
+  Timeout    = USB_BOT_RECV_CSW_TIMEOUT / USB_MASS_1_MILLISECOND;
 
-  for (Index = 0; Index < USB_BOT_GET_STATUS_RETRY; Index++) {
+  for (Index = 0; Index < USB_BOT_RECV_CSW_RETRY; Index++) {
     //
     // Attemp to the read CSW from bulk in endpoint
     //
@@ -499,7 +499,7 @@ UsbBotResetDevice (
   Request.Value       = 0;
   Request.Index       = UsbBot->Interface.InterfaceNumber;
   Request.Length      = 0;
-  Timeout             = USB_BOT_RESET_TIMEOUT / USB_MASS_STALL_1_MS;
+  Timeout             = USB_BOT_RESET_DEVICE_TIMEOUT / USB_MASS_1_MILLISECOND;
 
   Status = UsbBot->UsbIo->UsbControlTransfer (
                             UsbBot->UsbIo,
@@ -521,7 +521,7 @@ UsbBotResetDevice (
   // complete. We can use this to sync the device and host. For
   // now just stall 100ms to wait the device.
   //
-  gBS->Stall (USB_BOT_RESET_STALL);
+  gBS->Stall (USB_BOT_RESET_DEVICE_STALL);
 
   //
   // Clear the Bulk-In and Bulk-Out stall condition.

MdeModulePkg/Bus/Usb/UsbMassStorageDxe/UsbMassBot.h

@@ -46,21 +46,21 @@ enum {
   USB_BOT_COMMAND_ERROR    = 0x02, // Phase error, need to reset the device
 
   //
-  // Usb Bot retry times
+  // Usb Bot retry to get CSW, refers to specification[BOT10-5.3, it says 2 times]
   //
-  USB_BOT_GET_STATUS_RETRY = 3,
+  USB_BOT_RECV_CSW_RETRY       = 3,
 
   //
-  // Usb Bot stall time
+  // Usb Bot wait device reset complete, set by experience
   //  
-  USB_BOT_RESET_STALL      = 100 * USB_MASS_STALL_1_MS,
+  USB_BOT_RESET_DEVICE_STALL   = 100 * USB_MASS_1_MILLISECOND,
   
   //
-  // Usb Bot transfer timeout
+  // Usb Bot transport timeout, set by experience
   //
-  USB_BOT_CBW_TIMEOUT      = 1 * USB_MASS_STALL_1_S,
+  USB_BOT_SEND_CBW_TIMEOUT     = 3 * USB_MASS_1_SECOND,
-  USB_BOT_CSW_TIMEOUT      = 1 * USB_MASS_STALL_1_S,
+  USB_BOT_RECV_CSW_TIMEOUT     = 3 * USB_MASS_1_SECOND,
-  USB_BOT_RESET_TIMEOUT    = 3 * USB_MASS_STALL_1_S
+  USB_BOT_RESET_DEVICE_TIMEOUT = 3 * USB_MASS_1_SECOND,
 };
 
 //

MdeModulePkg/Bus/Usb/UsbMassStorageDxe/UsbMassCbi.c

@@ -194,7 +194,7 @@ UsbCbiSendCommand (
   Request.Length      = CmdLen;
 
   Status              = EFI_SUCCESS;
-  Timeout             = Timeout / USB_MASS_STALL_1_MS;
+  Timeout             = Timeout / USB_MASS_1_MILLISECOND;
 
   for (Retry = 0; Retry < USB_CBI_MAX_RETRY; Retry++) {
     //
@@ -281,7 +281,7 @@ UsbCbiDataTransfer (
   Remain  = *TransLen;
   Retry   = 0;
   Status  = EFI_SUCCESS;
-  Timeout = Timeout / USB_MASS_STALL_1_MS;
+  Timeout = Timeout / USB_MASS_1_MILLISECOND;
 
   //
   // Transfer the data, if the device returns NAK, retry it.
@@ -376,7 +376,7 @@ UsbCbiGetStatus (
 
   Endpoint  = UsbCbi->InterruptEndpoint->EndpointAddress;
   Status    = EFI_SUCCESS;
-  Timeout   = Timeout / USB_MASS_STALL_1_MS;
+  Timeout   = Timeout / USB_MASS_1_MILLISECOND;
 
   //
   // Attemp to the read the result from interrupt endpoint
@@ -555,7 +555,7 @@ UsbCbiResetDevice (
 
   ResetCmd[0] = 0x1D;
   ResetCmd[1] = 0x04;
-  Timeout     = USB_CBI_RESET_TIMEOUT / USB_MASS_STALL_1_MS;
+  Timeout     = USB_CBI_RESET_DEVICE_TIMEOUT / USB_MASS_1_MILLISECOND;
 
   //
   // Send the command to the device. Don't use UsbCbiExecCommand here.
@@ -570,7 +570,7 @@ UsbCbiResetDevice (
   // 50ms to wait it complete
   //
   UsbCbiGetStatus (UsbCbi, Timeout, &Result);
-  gBS->Stall (50 * 1000);
+  gBS->Stall (USB_CBI_RESET_DEVICE_STALL);
 
   //
   // Clear the Bulk-In and Bulk-Out stall condition and

MdeModulePkg/Bus/Usb/UsbMassStorageDxe/UsbMassCbi.h

@@ -30,14 +30,19 @@ enum {
   USB_CBI_RESET_CMD_LEN         = 12,
 
   //
-  // Usb CBI retry times
+  // Usb Cbi retry C/B/I transport times, set by experience
   //
   USB_CBI_MAX_RETRY             = 3,
 
   //
-  // Usb Cbi transfer timeout
+  // Usb Cbi wait device reset complete, set by experience
   //  
-  USB_CBI_RESET_TIMEOUT         = 1 * USB_MASS_STALL_1_S
+  USB_CBI_RESET_DEVICE_STALL    = 50 * USB_MASS_1_MILLISECOND,
+
+  //
+  // Usb Cbi transport timeout, set by experience
+  //
+  USB_CBI_RESET_DEVICE_TIMEOUT  = 1 * USB_MASS_1_SECOND,
 };
 
 //

MdeModulePkg/Bus/Usb/UsbMassStorageDxe/UsbMassImpl.c

@@ -91,7 +91,7 @@ UsbMassInitMedia (
   //
   Status = EFI_SUCCESS;
 
-  for (Index = 0; Index < USB_BOOT_WAIT_RETRY; Index++) {
+  for (Index = 0; Index < USB_BOOT_INIT_MEDIA_RETRY; Index++) {
 
     Status = UsbBootGetParams (UsbMass);
     if ((Status != EFI_MEDIA_CHANGED)
@@ -102,7 +102,7 @@ UsbMassInitMedia (
 
     Status = UsbBootIsUnitReady (UsbMass);
     if (EFI_ERROR (Status)) {
-      gBS->Stall (USB_BOOT_UNIT_READY_STALL * (Index + 1));
+      gBS->Stall (USB_BOOT_RETRY_UNIT_READY_STALL * (Index + 1)); 
     }
 
   }
@@ -128,9 +128,17 @@ UsbMassReset (
   )
 {
   USB_MASS_DEVICE *UsbMass;
+  EFI_TPL         OldTpl;
+  EFI_STATUS      Status;
+
+  OldTpl  = gBS->RaiseTPL (USB_MASS_TPL);
 
   UsbMass = USB_MASS_DEVICE_FROM_BLOCKIO (This);
-  return UsbMass->Transport->Reset (UsbMass->Context, ExtendedVerification);
+  Status  = UsbMass->Transport->Reset (UsbMass->Context, ExtendedVerification);
+
+  gBS->RestoreTPL (OldTpl);
+
+  return Status;
 }
 
 
@@ -165,8 +173,10 @@ UsbMassReadBlocks (
   USB_MASS_DEVICE     *UsbMass;
   EFI_BLOCK_IO_MEDIA  *Media;
   EFI_STATUS          Status;
+  EFI_TPL             OldTpl;
   UINTN               TotalBlock;
   
+  OldTpl  = gBS->RaiseTPL (USB_MASS_TPL);
   UsbMass = USB_MASS_DEVICE_FROM_BLOCKIO (This);
   Media   = &UsbMass->BlockIoMedia;
 
@@ -174,32 +184,37 @@ UsbMassReadBlocks (
   // First, validate the parameters
   //
   if ((Buffer == NULL) || (BufferSize == 0)) {
-    return EFI_INVALID_PARAMETER;
+    Status = EFI_INVALID_PARAMETER;
+    goto ON_EXIT;
   }
   
   //
-  // If it is a remoable media, such as CD-Rom or Usb-Floppy,
+  // If it is a removable media, such as CD-Rom or Usb-Floppy,
-  // if, need to detect the media before each rw, while Usb-Flash
+  // need to detect the media before each rw. While some of 
-  // needn't. However, it's hard to identify Usb-Floppy between
+  // Usb-Flash is marked as removable media.
-  // Usb-Flash by now, so detect media every time.
   // 
+  // 
+  if (Media->RemovableMedia == TRUE) {
     Status = UsbBootDetectMedia (UsbMass);
     if (EFI_ERROR (Status)) {
       DEBUG ((mUsbMscError, "UsbMassReadBlocks: UsbBootDetectMedia (%r)\n", Status));
-    return Status;
+      goto ON_EXIT;
+    } 
   }
   
   //
   // Make sure BlockSize and LBA is consistent with BufferSize
   //
   if ((BufferSize % Media->BlockSize) != 0) {
-    return EFI_BAD_BUFFER_SIZE;
+    Status = EFI_BAD_BUFFER_SIZE;
+    goto ON_EXIT;
   }
 
   TotalBlock = BufferSize / Media->BlockSize;
 
   if (Lba + TotalBlock - 1 > Media->LastBlock) {
-    return EFI_BAD_BUFFER_SIZE;
+    Status = EFI_BAD_BUFFER_SIZE;
+    goto ON_EXIT;
   }
   
   Status = UsbBootReadBlocks (UsbMass, (UINT32) Lba, TotalBlock, Buffer);
@@ -208,6 +223,8 @@ UsbMassReadBlocks (
     UsbMassReset (This, TRUE);
   }
 
+ON_EXIT:
+  gBS->RestoreTPL (OldTpl);
   return Status;
 }
 
@@ -243,8 +260,10 @@ UsbMassWriteBlocks (
   USB_MASS_DEVICE     *UsbMass;
   EFI_BLOCK_IO_MEDIA  *Media;
   EFI_STATUS          Status;
+  EFI_TPL             OldTpl;
   UINTN               TotalBlock;
 
+  OldTpl  = gBS->RaiseTPL (USB_MASS_TPL);
   UsbMass = USB_MASS_DEVICE_FROM_BLOCKIO (This);
   Media   = &UsbMass->BlockIoMedia;
 
@@ -252,32 +271,37 @@ UsbMassWriteBlocks (
   // First, validate the parameters
   //
   if ((Buffer == NULL) || (BufferSize == 0)) {
-    return EFI_INVALID_PARAMETER;
+    Status = EFI_INVALID_PARAMETER;
+    goto ON_EXIT;
   }
   
   //
-  // If it is a remoable media, such as CD-Rom or Usb-Floppy,
+  // If it is a removable media, such as CD-Rom or Usb-Floppy,
-  // if, need to detect the media before each rw, while Usb-Flash
+  // need to detect the media before each rw. While some of 
-  // needn't. However, it's hard to identify Usb-Floppy between
+  // Usb-Flash is marked as removable media.
-  // Usb-Flash by now, so detect media every time.
   // 
+  // 
+  if (Media->RemovableMedia == TRUE) {
     Status = UsbBootDetectMedia (UsbMass);
     if (EFI_ERROR (Status)) {
       DEBUG ((mUsbMscError, "UsbMassWriteBlocks: UsbBootDetectMedia (%r)\n", Status));
-    return Status;
+      goto ON_EXIT;
+    } 
   }
   
   //
   // Make sure BlockSize and LBA is consistent with BufferSize
   //
   if ((BufferSize % Media->BlockSize) != 0) {
-    return EFI_BAD_BUFFER_SIZE;
+    Status = EFI_BAD_BUFFER_SIZE;
+    goto ON_EXIT;
   }
 
   TotalBlock = BufferSize / Media->BlockSize;
 
   if (Lba + TotalBlock - 1 > Media->LastBlock) {
-    return EFI_BAD_BUFFER_SIZE;
+    Status = EFI_BAD_BUFFER_SIZE;
+    goto ON_EXIT;
   }
   
   //
@@ -290,6 +314,8 @@ UsbMassWriteBlocks (
     UsbMassReset (This, TRUE);
   }
   
+ON_EXIT:
+  gBS->RestoreTPL (OldTpl);
   return Status;
 }
 

MdeModulePkg/Bus/Usb/UsbMassStorageDxe/UsbMassImpl.h

@@ -33,7 +33,13 @@ typedef struct _USB_MASS_DEVICE USB_MASS_DEVICE;
 #include "UsbMassBoot.h"
 
 enum {
-  USB_MASS_SIGNATURE= EFI_SIGNATURE_32 ('U', 's', 'b', 'K')
+  //
+  // MassStorage raises TPL to TPL_NOTIFY to serialize all its operations
+  // to protect shared data structures.
+  //
+  USB_MASS_TPL          = TPL_NOTIFY,
+  
+  USB_MASS_SIGNATURE    = EFI_SIGNATURE_32 ('U', 's', 'b', 'M'),
 };
 
 struct _USB_MASS_DEVICE {