UefiCpuPkg/CpuDxe: Fix hard code actual TimerPeriod value

[mirror_edk2.git] / UefiCpuPkg / CpuDxe / CpuDxe.c

diff --git a/UefiCpuPkg/CpuDxe/CpuDxe.c b/UefiCpuPkg/CpuDxe/CpuDxe.c
index c5be1ff124bb5fd49e0f60d3b029b4f993b72791..1a5a725c6dce03450ee3097bb7c928b1fc25d06c 100644 (file)
--- a/UefiCpuPkg/CpuDxe/CpuDxe.c
+++ b/UefiCpuPkg/CpuDxe/CpuDxe.c
@@ -27,6 +27,7 @@ EFI_HANDLE                mCpuHandle = NULL;
 BOOLEAN                   mIsFlushingGCD;\r
 UINT64                    mValidMtrrAddressMask = MTRR_LIB_CACHE_VALID_ADDRESS;\r
 UINT64                    mValidMtrrBitsMask    = MTRR_LIB_MSR_VALID_MASK;\r
+UINT64                    mTimerPeriod = 0;\r
 \r
 FIXED_MTRR    mFixedMtrrTable[] = {\r
   {\r
@@ -297,6 +298,9 @@ CpuGetTimerValue (
   OUT UINT64                    *TimerPeriod OPTIONAL\r
   )\r
 {\r
+  UINT64          BeginValue;\r
+  UINT64          EndValue;\r
+\r
   if (TimerValue == NULL) {\r
     return EFI_INVALID_PARAMETER;\r
   }\r
@@ -308,10 +312,26 @@ CpuGetTimerValue (
   *TimerValue = AsmReadTsc ();\r
 \r
   if (TimerPeriod != NULL) {\r
+    if (mTimerPeriod == 0) {\r
+      //\r
+      // Read time stamp counter before and after delay of 100 microseconds\r
       //\r
-      // BugBug: Hard coded. Don't know how to do this generically\r
+      BeginValue = AsmReadTsc ();\r
+      MicroSecondDelay (100);\r
+      EndValue   = AsmReadTsc ();\r
       //\r
-      *TimerPeriod = 1000000000;\r
+      // Calculate the actual frequency\r
+      //\r
+      mTimerPeriod = DivU64x64Remainder (\r
+                       MultU64x32 (\r
+                         1000 * 1000 * 1000,\r
+                         100\r
+                         ),\r
+                       EndValue - BeginValue,\r
+                       NULL\r
+                       );\r
+    }\r
+    *TimerPeriod = mTimerPeriod;\r
   }\r
 \r
   return EFI_SUCCESS;\r