[PATCH v2 01/13] arm64: kernel: add MPIDR_EL1 accessors macros

On Tue, Oct 15, 2013 at 11:11:30AM +0100, Will Deacon wrote:

On Mon, Oct 14, 2013 at 12:02:58PM +0100, Lorenzo Pieralisi wrote:

quoted

In order to simplify access to different affinity levels within the
MPIDR_EL1 register values, this patch implements some preprocessor
macros that allow to retrieve the MPIDR_EL1 affinity level value according
to the level passed as input parameter.

Signed-off-by: Lorenzo Pieralisi <redacted>
---
 arch/arm64/include/asm/cputype.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h
index 5fe138e..2c9e295 100644
--- a/arch/arm64/include/asm/cputype.h
+++ b/arch/arm64/include/asm/cputype.h

@@ -30,6 +30,16 @@
 
 #define MPIDR_HWID_BITMASK	0xff00ffffff
 
+#define MPIDR_LEVEL_BITS 8
+#define MPIDR_LEVEL_MASK ((1 << MPIDR_LEVEL_BITS) - 1)
+
+#define MPIDR_LEVEL_SHIFT(level) ({					\
+	(level == 3) ? 32 : MPIDR_LEVEL_BITS * level;			\

You can avoid the check if you do:

  ((1 << level) >> 1) << 3)

where that '3' is log2 MPIDR_LEVEL_BITS, so you could factor that out and
redefine MPIDR_LEVEL_BITS in terms of a shift.

Yes, that's ways neater, thank you.

Lorenzo