Re: [PATCH v6 11/22] ArmPkg: Add helper to read the CCSIDR2 register

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

Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>

Regards,

Sami Mujawar

-----Original Message-----
From: Rebecca Cran <rebecca@nuviainc.com> 
Sent: 14 January 2021 04:36 PM
To: devel@edk2.groups.io
Cc: Rebecca Cran <rebecca@nuviainc.com>; Leif Lindholm <leif@nuviainc.com>; Ard Biesheuvel <Ard.Biesheuvel@arm.com>; nd <nd@arm.com>; Sami Mujawar <Sami.Mujawar@arm.com>; Liming Gao <gaoliming@byosoft.com.cn>; Michael D Kinney <michael.d.kinney@intel.com>; Zhiguang Liu <zhiguang.liu@intel.com>
Subject: [PATCH v6 11/22] ArmPkg: Add helper to read the CCSIDR2 register

Add helper function to read the CCSIDR2 register.
This is used when CCIDX is supported in AARCH32 mode.

Signed-off-by: Rebecca Cran <rebecca@nuviainc.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
---
 ArmPkg/Library/ArmLib/ArmLibPrivate.h         | 11 +++++++++++
 ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.S   | 10 ++++++++++
 ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.asm | 10 ++++++++++
 3 files changed, 31 insertions(+)

diff --git a/ArmPkg/Library/ArmLib/ArmLibPrivate.h b/ArmPkg/Library/ArmLib/ArmLibPrivate.h
index 77e592a99def..4b72827a6522 100644
--- a/ArmPkg/Library/ArmLib/ArmLibPrivate.h
+++ b/ArmPkg/Library/ArmLib/ArmLibPrivate.h
@@ -170,6 +170,17 @@ ReadCCSIDR (
   IN UINT32 CSSELR
   );
 
+/** Reads the CCSIDR2 for the specified cache.
+
+  @param CSSELR The CSSELR cache selection register value
+
+  @return The contents of the CCSIDR2 register for the specified cache.
+**/
+UINT32
+ReadCCSIDR2 (
+  IN UINT32 CSSELR
+  );
+
 UINT32
 ReadCLIDR (
   VOID
diff --git a/ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.S b/ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.S
index af61dbee5261..d843f91dfca8 100644
--- a/ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.S
+++ b/ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.S
@@ -74,6 +74,16 @@ ASM_FUNC(ReadCCSIDR)
   mrc p15,1,r0,c0,c0,0   @ Read current CP15 Cache Size ID Register (CCSIDR)
   bx  lr
 
+// UINT32
+// ReadCCSIDR2 (
+//   IN UINT32 CSSELR
+//   )
+ASM_FUNC(ReadCCSIDR2)
+  mcr p15,2,r0,c0,c0,0   @ Write Cache Size Selection Register (CSSELR)
+  isb
+  mrc p15,1,r0,c0,c0,2   @ Read current CP15 Cache Size ID Register (CCSIDR2)
+  bx  lr
+
 // UINT32
 // ReadCLIDR (
 //   IN UINT32 CSSELR
diff --git a/ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.asm b/ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.asm
index 81f3cb79994c..e14f1566258c 100644
--- a/ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.asm
+++ b/ArmPkg/Library/ArmLib/Arm/ArmLibSupportV7.asm
@@ -78,6 +78,16 @@
   mrc p15,1,r0,c0,c0,0 ; Read current CP15 Cache Size ID Register (CCSIDR)
   bx  lr
 
+// UINT32
+// ReadCCSIDR2 (
+//   IN UINT32 CSSELR
+//   )
+ RVCT_ASM_EXPORT ReadCCSIDR2
+  mcr p15,2,r0,c0,c0,0 ; Write Cache Size Selection Register (CSSELR)
+  isb
+  mrc p15,1,r0,c0,c0,2 ; Read current CP15 Cache Size ID Register (CCSIDR2)
+  bx  lr
+
 // UINT32
 // ReadCLIDR (
 //   IN UINT32 CSSELR
-- 
2.26.2