ARM: 8602/1: factor out CSSELR/CCSIDR operations that use cp15 directly

Currently we use raw cp15 operations to access the cache setup data.

This patch abstracts the CSSELR and CCSIDR accessors out to a header so
that the implementation for them can be switched out as we do with other
cpu/cachetype operations.

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>

arch/arm/include/asm/cachetype.h

@@ -56,4 +56,28 @@ static inline unsigned int __attribute__((pure)) cacheid_is(unsigned int mask)
 	       (~__CACHEID_NEVER & __CACHEID_ARCH_MIN & mask & cacheid);
 }
 
+#define CSSELR_ICACHE	1
+#define CSSELR_DCACHE	0
+
+#define CSSELR_L1	(0 << 1)
+#define CSSELR_L2	(1 << 1)
+#define CSSELR_L3	(2 << 1)
+#define CSSELR_L4	(3 << 1)
+#define CSSELR_L5	(4 << 1)
+#define CSSELR_L6	(5 << 1)
+#define CSSELR_L7	(6 << 1)
+
+static inline void set_csselr(unsigned int cache_selector)
+{
+	asm volatile("mcr p15, 2, %0, c0, c0, 0" : : "r" (cache_selector));
+}
+
+static inline unsigned int read_ccsidr(void)
+{
+	unsigned int val;
+
+	asm volatile("mrc p15, 1, %0, c0, c0, 0" : "=r" (val));
+	return val;
+}
+
 #endif

arch/arm/kernel/setup.c

@@ -290,12 +290,9 @@ static int cpu_has_aliasing_icache(unsigned int arch)
 	/* arch specifies the register format */
 	switch (arch) {
 	case CPU_ARCH_ARMv7:
-		asm("mcr	p15, 2, %0, c0, c0, 0 @ set CSSELR"
-		    : /* No output operands */
-		    : "r" (1));
+		set_csselr(CSSELR_ICACHE | CSSELR_L1);
 		isb();
-		asm("mrc	p15, 1, %0, c0, c0, 0 @ read CCSIDR"
-		    : "=r" (id_reg));
+		id_reg = read_ccsidr();
 		line_size = 4 << ((id_reg & 0x7) + 2);
 		num_sets = ((id_reg >> 13) & 0x7fff) + 1;
 		aliasing_icache = (line_size * num_sets) > PAGE_SIZE;