[edk2-devel] [PATCH v3 12/13] ArmPkg/ArmLib: Add ArmHasTrbe () helper function

["Sami Mujawar" <sami.mujawar@arm.com>]

Create a helper function to query whether ID_AA64MFR1_EL1 indicates
presence of the Trace Buffer Extension (TRBE). This feature is only
visible in AARCH64 state.

Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Pierre Gondois <pierre.gondois@arm.com>
---

Notes:
    v3:
     - New patch in this series that introduces a helper      [SAMI]
       function for platforms to query if TRBE feature is
       supported.
       Ref: https://edk2.groups.io/g/devel/message/108986

 ArmPkg/Include/Chipset/AArch64.h           |  3 +++
 ArmPkg/Include/Library/ArmLib.h            | 13 +++++++++++++
 ArmPkg/Library/ArmLib/AArch64/AArch64Lib.c | 15 +++++++++++++++
 3 files changed, 31 insertions(+)

diff --git a/ArmPkg/Include/Chipset/AArch64.h b/ArmPkg/Include/Chipset/AArch64.h
index 2e87917049f9c50af9bf674a5ca32d1ae6f072c3..d8711ad7112f1f983d22d98bdf8ff8607bf2ff98 100644
--- a/ArmPkg/Include/Chipset/AArch64.h
+++ b/ArmPkg/Include/Chipset/AArch64.h
@@ -31,6 +31,9 @@
 #define AARCH64_PFR0_FP   (0xF << 16)
 #define AARCH64_PFR0_GIC  (0xF << 24)
 
+// ID_AA64DFR0 - AArch64 Debug Feature Register 0 definitions
+#define AARCH64_DFR0_TRBE  (0xFULL << 44)
+
 // SCR - Secure Configuration Register definitions
 #define SCR_NS   (1 << 0)
 #define SCR_IRQ  (1 << 1)
diff --git a/ArmPkg/Include/Library/ArmLib.h b/ArmPkg/Include/Library/ArmLib.h
index 0169dbc1092cddae684362c07c8d5fe3d8809b91..c2d738c06e27a3599b79c7bd83c72f8a696b4aef 100644
--- a/ArmPkg/Include/Library/ArmLib.h
+++ b/ArmPkg/Include/Library/ArmLib.h
@@ -780,6 +780,19 @@ EFIAPI
 ArmHasVhe (
   VOID
   );
+
+/**
+  Checks whether the CPU implements the Trace Buffer Extension.
+
+  @retval TRUE  FEAT_TRBE is implemented.
+  @retval FALSE FEAT_TRBE is not mplemented.
+**/
+BOOLEAN
+EFIAPI
+ArmHasTrbe (
+  VOID
+  );
+
 #endif // MDE_CPU_AARCH64
 
 #ifdef MDE_CPU_ARM
diff --git a/ArmPkg/Library/ArmLib/AArch64/AArch64Lib.c b/ArmPkg/Library/ArmLib/AArch64/AArch64Lib.c
index da5755106e623da92be8455af7159e66e5c48661..3a46f360ef512ed68f9ec80fc486551ff7440009 100644
--- a/ArmPkg/Library/ArmLib/AArch64/AArch64Lib.c
+++ b/ArmPkg/Library/ArmLib/AArch64/AArch64Lib.c
@@ -119,3 +119,18 @@ ArmHasVhe (
 {
   return ((ArmReadIdAA64Mmfr1 () & AARCH64_MMFR1_VH) != 0);
 }
+
+/**
+  Checks whether the CPU implements the Trace Buffer Extension.
+
+  @retval TRUE  FEAT_TRBE is implemented.
+  @retval FALSE FEAT_TRBE is not mplemented.
+**/
+BOOLEAN
+EFIAPI
+ArmHasTrbe (
+  VOID
+  )
+{
+  return ((ArmReadIdAA64Dfr0 () & AARCH64_DFR0_TRBE) != 0);
+}
-- 
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'



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