ARM: 8604/1: V7M: Add support for reading the CTR with read_cpuid_cachetype()

With the addition of caches to the V7M Architecture a new Cache Type
Register (CTR) is defined at 0xE000ED7C. This register serves the same
purpose as the V7A/R version and accessed via the read_cpuid_cachetype.

Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Tested-by: Andras Szemzo <sza@esh.hu>
Tested-by: Joachim Eastwood <manabian@gmail.com>
Tested-by: Alexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 30 insertions, 9 deletions

diff --git a/arch/arm/include/asm/cachetype.h b/arch/arm/include/asm/cachetype.h
index 8609de8e313a..01509ae0bbec 100644
--- a/arch/arm/include/asm/cachetype.h
+++ b/arch/arm/include/asm/cachetype.h
@@ -67,6 +67,7 @@ static inline unsigned int __attribute__((pure)) cacheid_is(unsigned int mask)
 #define CSSELR_L6       (5 << 1)
 #define CSSELR_L7       (6 << 1)
 
+#ifndef CONFIG_CPU_V7M
 static inline void set_csselr(unsigned int cache_selector)
 {
         asm volatile("mcr p15, 2, %0, c0, c0, 0" : : "r" (cache_selector));
@@ -79,5 +80,19 @@ static inline unsigned int read_ccsidr(void)
         asm volatile("mrc p15, 1, %0, c0, c0, 0" : "=r" (val));
         return val;
 }
+#else /* CONFIG_CPU_V7M */
+#include <linux/io.h>
+#include "asm/v7m.h"
+
+static inline void set_csselr(unsigned int cache_selector)
+{
+        writel(cache_selector, BASEADDR_V7M_SCB + V7M_SCB_CTR);
+}
+
+static inline unsigned int read_ccsidr(void)
+{
+        return readl(BASEADDR_V7M_SCB + V7M_SCB_CCSIDR);
+}
+#endif
 
 #endif
diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h
index d6a4902a75d7..754f86f667d4 100644
--- a/arch/arm/include/asm/cputype.h
+++ b/arch/arm/include/asm/cputype.h
@@ -164,6 +164,11 @@ static inline unsigned int __attribute_const__ read_cpuid_id(void)
         return read_cpuid(CPUID_ID);
 }
 
+static inline unsigned int __attribute_const__ read_cpuid_cachetype(void)
+{
+        return read_cpuid(CPUID_CACHETYPE);
+}
+
 #elif defined(CONFIG_CPU_V7M)
 
 static inline unsigned int __attribute_const__ read_cpuid_id(void)
@@ -171,6 +176,11 @@ static inline unsigned int __attribute_const__ read_cpuid_id(void)
         return readl(BASEADDR_V7M_SCB + V7M_SCB_CPUID);
 }
 
+static inline unsigned int __attribute_const__ read_cpuid_cachetype(void)
+{
+        return readl(BASEADDR_V7M_SCB + V7M_SCB_CTR);
+}
+
 #else /* ifdef CONFIG_CPU_CP15 / elif defined(CONFIG_CPU_V7M) */
 
 static inline unsigned int __attribute_const__ read_cpuid_id(void)
@@ -210,11 +220,6 @@ static inline unsigned int __attribute_const__ xscale_cpu_arch_version(void)
         return read_cpuid_id() & ARM_CPU_XSCALE_ARCH_MASK;
 }
 
-static inline unsigned int __attribute_const__ read_cpuid_cachetype(void)
-{
-        return read_cpuid(CPUID_CACHETYPE);
-}
-
 static inline unsigned int __attribute_const__ read_cpuid_tcmstatus(void)
 {
         return read_cpuid(CPUID_TCM);
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index d7568808eb7b..34e3f3c45634 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -312,11 +312,12 @@ static void __init cacheid_init(void)
 {
         unsigned int arch = cpu_architecture();
 
-        if (arch == CPU_ARCH_ARMv7M) {
-                cacheid = 0;
-        } else if (arch >= CPU_ARCH_ARMv6) {
+        if (arch >= CPU_ARCH_ARMv6) {
                 unsigned int cachetype = read_cpuid_cachetype();
-                if ((cachetype & (7 << 29)) == 4 << 29) {
+
+                if ((arch == CPU_ARCH_ARMv7M) && !cachetype) {
+                        cacheid = 0;
+                } else if ((cachetype & (7 << 29)) == 4 << 29) {
                         /* ARMv7 register format */
                         arch = CPU_ARCH_ARMv7;
                         cacheid = CACHEID_VIPT_NONALIASING;