From 6f4e10d6db316c279ed90036c9a206a1b89f0878 Mon Sep 17 00:00:00 2001
From: Qi Zhang <qi1.zhang@intel.com>
Date: Fri, 29 Jul 2022 09:02:21 +0800
Subject: SecurityPkg: Add retry mechanism for tpm command

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3980

As per TCG PC Client Device Driver Design Principle document,
if tpm commands fails due to timeout condition, then it should
have retry mechanism (3 retry attempts).
Existing implementation of PtpCrbTpmCommand does not have retry
mechanism if it fails with EFI_TIMEOUT.

See TCG PC Client Device Driver Design Principles for TPM 2.0
https://trustedcomputinggroup.org/wp-content/uploads/TCG_PCClient_Device_Driver_Design_Principles_TPM2p0_v1p1_r4_211104_final.pdf
Vision 1.1, Revision 0.04
Section 7.2.1

Signed-off-by: Qi Zhang <qi1.zhang@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Tested-by: Swapnil Patil <S.Keshavrao.Patil@dell.com>
---
 SecurityPkg/Library/Tpm2DeviceLibDTpm/Tpm2Ptp.c | 108 +++++++++++++++---------
 1 file changed, 69 insertions(+), 39 deletions(-)

(limited to 'SecurityPkg')

diff --git a/SecurityPkg/Library/Tpm2DeviceLibDTpm/Tpm2Ptp.c b/SecurityPkg/Library/Tpm2DeviceLibDTpm/Tpm2Ptp.c
index 1d99bea..8402652 100644
--- a/SecurityPkg/Library/Tpm2DeviceLibDTpm/Tpm2Ptp.c
+++ b/SecurityPkg/Library/Tpm2DeviceLibDTpm/Tpm2Ptp.c
@@ -33,6 +33,12 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 //
 #define TPMCMDBUFLENGTH  0x500
 
+//
+// Max retry count according to Spec TCG PC Client Device Driver Design Principles
+// for TPM2.0, Version 1.1, Revision 0.04, Section 7.2.1
+//
+#define RETRY_CNT_MAX  3
+
 /**
   Check whether TPM PTP register exist.
 
@@ -153,6 +159,7 @@ PtpCrbTpmCommand (
   UINT32      TpmOutSize;
   UINT16      Data16;
   UINT32      Data32;
+  UINT8       RetryCnt;
 
   DEBUG_CODE_BEGIN ();
   UINTN  DebugSize;
@@ -179,53 +186,76 @@ PtpCrbTpmCommand (
   DEBUG_CODE_END ();
   TpmOutSize = 0;
 
-  //
-  // STEP 0:
-  // if CapCRbIdelByPass == 0, enforce Idle state before sending command
-  //
-  if ((GetCachedIdleByPass () == 0) && ((MmioRead32 ((UINTN)&CrbReg->CrbControlStatus) & PTP_CRB_CONTROL_AREA_STATUS_TPM_IDLE) == 0)) {
+  RetryCnt = 0;
+  while (TRUE) {
+    //
+    // STEP 0:
+    // if CapCRbIdelByPass == 0, enforce Idle state before sending command
+    //
+    if ((GetCachedIdleByPass () == 0) && ((MmioRead32 ((UINTN)&CrbReg->CrbControlStatus) & PTP_CRB_CONTROL_AREA_STATUS_TPM_IDLE) == 0)) {
+      Status = PtpCrbWaitRegisterBits (
+                 &CrbReg->CrbControlStatus,
+                 PTP_CRB_CONTROL_AREA_STATUS_TPM_IDLE,
+                 0,
+                 PTP_TIMEOUT_C
+                 );
+      if (EFI_ERROR (Status)) {
+        RetryCnt++;
+        if (RetryCnt < RETRY_CNT_MAX) {
+          MmioWrite32 ((UINTN)&CrbReg->CrbControlRequest, PTP_CRB_CONTROL_AREA_REQUEST_GO_IDLE);
+          continue;
+        } else {
+          //
+          // Try to goIdle to recover TPM
+          //
+          Status = EFI_DEVICE_ERROR;
+          goto GoIdle_Exit;
+        }
+      }
+    }
+
+    //
+    // STEP 1:
+    // Ready is any time the TPM is ready to receive a command, following a write
+    // of 1 by software to Request.cmdReady, as indicated by the Status field
+    // being cleared to 0.
+    //
+    MmioWrite32 ((UINTN)&CrbReg->CrbControlRequest, PTP_CRB_CONTROL_AREA_REQUEST_COMMAND_READY);
     Status = PtpCrbWaitRegisterBits (
-               &CrbReg->CrbControlStatus,
-               PTP_CRB_CONTROL_AREA_STATUS_TPM_IDLE,
+               &CrbReg->CrbControlRequest,
                0,
+               PTP_CRB_CONTROL_AREA_REQUEST_COMMAND_READY,
                PTP_TIMEOUT_C
                );
     if (EFI_ERROR (Status)) {
-      //
-      // Try to goIdle to recover TPM
-      //
-      Status = EFI_DEVICE_ERROR;
-      goto GoIdle_Exit;
+      RetryCnt++;
+      if (RetryCnt < RETRY_CNT_MAX) {
+        MmioWrite32 ((UINTN)&CrbReg->CrbControlRequest, PTP_CRB_CONTROL_AREA_REQUEST_GO_IDLE);
+        continue;
+      } else {
+        Status = EFI_DEVICE_ERROR;
+        goto GoIdle_Exit;
+      }
     }
-  }
 
-  //
-  // STEP 1:
-  // Ready is any time the TPM is ready to receive a command, following a write
-  // of 1 by software to Request.cmdReady, as indicated by the Status field
-  // being cleared to 0.
-  //
-  MmioWrite32 ((UINTN)&CrbReg->CrbControlRequest, PTP_CRB_CONTROL_AREA_REQUEST_COMMAND_READY);
-  Status = PtpCrbWaitRegisterBits (
-             &CrbReg->CrbControlRequest,
-             0,
-             PTP_CRB_CONTROL_AREA_REQUEST_COMMAND_READY,
-             PTP_TIMEOUT_C
-             );
-  if (EFI_ERROR (Status)) {
-    Status = EFI_DEVICE_ERROR;
-    goto GoIdle_Exit;
-  }
+    Status = PtpCrbWaitRegisterBits (
+               &CrbReg->CrbControlStatus,
+               0,
+               PTP_CRB_CONTROL_AREA_STATUS_TPM_IDLE,
+               PTP_TIMEOUT_C
+               );
+    if (EFI_ERROR (Status)) {
+      RetryCnt++;
+      if (RetryCnt < RETRY_CNT_MAX) {
+        MmioWrite32 ((UINTN)&CrbReg->CrbControlRequest, PTP_CRB_CONTROL_AREA_REQUEST_GO_IDLE);
+        continue;
+      } else {
+        Status = EFI_DEVICE_ERROR;
+        goto GoIdle_Exit;
+      }
+    }
 
-  Status = PtpCrbWaitRegisterBits (
-             &CrbReg->CrbControlStatus,
-             0,
-             PTP_CRB_CONTROL_AREA_STATUS_TPM_IDLE,
-             PTP_TIMEOUT_C
-             );
-  if (EFI_ERROR (Status)) {
-    Status = EFI_DEVICE_ERROR;
-    goto GoIdle_Exit;
+    break;
   }
 
   //
-- 
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