Function for revised cpuid format

PATCH Bahadir Balban 1 participant 1 message May 21, 2010

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Bahadir Balban

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2010-05-21 12:14 UTC #0 lore raw

Below is a patch for this. What do you think?

From 30ed7d843d61a9663b7fe8d2f8c67ede3d819e50 Mon Sep 17 00:00:00 2001
From: Bahadir Balban <[email protected]>
Date: Fri, 21 May 2010 14:39:56 +0300
Subject: [PATCH] Define revised cpuid function and convert assembler to use that.

This patch defines a minor function to read the revised cpuid format and converts an assembler statement to use this function.

Signed-off-by Bahadir Balban <[email protected]>

---
  arch/codezero/include/asm/cputype.h |    5 +++++
  arch/codezero/kernel/setup.c        |    5 ++---
  2 files changed, 7 insertions(+), 3 deletions(-)

arch/codezero/include/asm/cputype.h +5 -0

index 20ae96c..60071d8 100644
@@ -58,6 +58,11 @@ static inline unsigned int __attribute_const__ read_cpuid_id(void)
  	return read_cpuid(CPUID_ID);
  }
 
+static inline unsigned int __attribute_const__ read_cpuid_revised_id(void)
+{
+	return read_cpuid_ext(CPUID_EXT_MMFR0);
+}
+
  static inline unsigned int __attribute_const__ read_cpuid_cachetype(void)
  {
  	return read_cpuid(CPUID_CACHETYPE);

arch/codezero/kernel/setup.c +2 -3

index c91c77b..c64b029 100644
@@ -213,12 +213,11 @@ int cpu_architecture(void)
  		if (cpu_arch)
  			cpu_arch += CPU_ARCH_ARMv3;
  	} else if ((read_cpuid_id() & 0x000f0000) == 0x000f0000) {
-		unsigned int mmfr0;
 
  		/* Revised CPUID format. Read the Memory Model Feature
  		 * Register 0 and check for VMSAv7 or PMSAv7 */
-		asm("mrc	p15, 0, %0, c0, c1, 4"
-		    : "=r" (mmfr0));
+		unsigned int mmfr0 = read_cpuid_revised_id();
+
  		if ((mmfr0 & 0x0000000f) == 0x00000003 ||
  		    (mmfr0 & 0x000000f0) == 0x00000030)
  			cpu_arch = CPU_ARCH_ARMv7;

Signature · 4 lines

1.6.3.3

-- 
Bahadir