[ARM] 5488/1: ARM errata: Invalidation of the Instruction Cache operation can fail

This patch implements the recommended workaround for erratum 411920
(ARM1136, ARM1156, ARM1176).
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig

@@ -740,6 +740,15 @@ if !MMU
 source "arch/arm/Kconfig-nommu"
 endif
 
+config ARM_ERRATA_411920
+	bool "ARM errata: Invalidation of the Instruction Cache operation can fail"
+	depends on CPU_V6 && !SMP
+	help
+	  Invalidation of the Instruction Cache operation can
+	  fail. This erratum is present in 1136 (before r1p4), 1156 and 1176.
+	  It does not affect the MPCore. This option enables the ARM Ltd.
+	  recommended workaround.
+
 endmenu
 
 source "arch/arm/common/Kconfig"

arch/arm/mm/cache-v6.S

@@ -20,6 +20,31 @@
 #define D_CACHE_LINE_SIZE	32
 #define BTB_FLUSH_SIZE		8
 
+#ifdef CONFIG_ARM_ERRATA_411920
+/*
+ * Invalidate the entire I cache (this code is a workaround for the ARM1136
+ * erratum 411920 - Invalidate Instruction Cache operation can fail. This
+ * erratum is present in 1136, 1156 and 1176. It does not affect the MPCore.
+ *
+ * Registers:
+ *   r0 - set to 0
+ *   r1 - corrupted
+ */
+ENTRY(v6_icache_inval_all)
+	mov	r0, #0
+	mrs	r1, cpsr
+	cpsid	ifa				@ disable interrupts
+	mcr	p15, 0, r0, c7, c5, 0		@ invalidate entire I-cache
+	mcr	p15, 0, r0, c7, c5, 0		@ invalidate entire I-cache
+	mcr	p15, 0, r0, c7, c5, 0		@ invalidate entire I-cache
+	mcr	p15, 0, r0, c7, c5, 0		@ invalidate entire I-cache
+	msr	cpsr_cx, r1			@ restore interrupts
+	.rept	11				@ ARM Ltd recommends at least
+	nop					@ 11 NOPs
+	.endr
+	mov	pc, lr
+#endif
+
 /*
  *	v6_flush_cache_all()
  *
@@ -31,7 +56,11 @@ ENTRY(v6_flush_kern_cache_all)
 	mov	r0, #0
 #ifdef HARVARD_CACHE
 	mcr	p15, 0, r0, c7, c14, 0		@ D cache clean+invalidate
+#ifndef CONFIG_ARM_ERRATA_411920
 	mcr	p15, 0, r0, c7, c5, 0		@ I+BTB cache invalidate
+#else
+	b	v6_icache_inval_all
+#endif
 #else
 	mcr	p15, 0, r0, c7, c15, 0		@ Cache clean+invalidate
 #endif
@@ -103,7 +132,11 @@ ENTRY(v6_coherent_user_range)
 	mov	r0, #0
 #ifdef HARVARD_CACHE
 	mcr	p15, 0, r0, c7, c10, 4		@ drain write buffer
+#ifndef CONFIG_ARM_ERRATA_411920
 	mcr	p15, 0, r0, c7, c5, 0		@ I+BTB cache invalidate
+#else
+	b	v6_icache_inval_all
+#endif
 #else
 	mcr	p15, 0, r0, c7, c5, 6		@ invalidate BTB
 #endif

arch/arm/mm/flush.c

@@ -18,6 +18,10 @@
 
 #include "mm.h"
 
+#ifdef CONFIG_ARM_ERRATA_411920
+extern void v6_icache_inval_all(void);
+#endif
+
 #ifdef CONFIG_CPU_CACHE_VIPT
 
 #define ALIAS_FLUSH_START	0xffff4000
@@ -32,10 +36,15 @@ static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
 
 	asm(	"mcrr	p15, 0, %1, %0, c14\n"
 	"	mcr	p15, 0, %2, c7, c10, 4\n"
+#ifndef CONFIG_ARM_ERRATA_411920
 	"	mcr	p15, 0, %2, c7, c5, 0\n"
+#endif
 	    :
 	    : "r" (to), "r" (to + PAGE_SIZE - L1_CACHE_BYTES), "r" (zero)
 	    : "cc");
+#ifdef CONFIG_ARM_ERRATA_411920
+	v6_icache_inval_all();
+#endif
 }
 
 void flush_cache_mm(struct mm_struct *mm)
@@ -48,11 +57,16 @@ void flush_cache_mm(struct mm_struct *mm)
 
 	if (cache_is_vipt_aliasing()) {
 		asm(	"mcr	p15, 0, %0, c7, c14, 0\n"
+		"	mcr	p15, 0, %0, c7, c10, 4\n"
+#ifndef CONFIG_ARM_ERRATA_411920
 		"	mcr	p15, 0, %0, c7, c5, 0\n"
-		"	mcr	p15, 0, %0, c7, c10, 4"
+#endif
 		    :
 		    : "r" (0)
 		    : "cc");
+#ifdef CONFIG_ARM_ERRATA_411920
+		v6_icache_inval_all();
+#endif
 	}
 }
 
@@ -67,11 +81,16 @@ void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned
 
 	if (cache_is_vipt_aliasing()) {
 		asm(	"mcr	p15, 0, %0, c7, c14, 0\n"
+		"	mcr	p15, 0, %0, c7, c10, 4\n"
+#ifndef CONFIG_ARM_ERRATA_411920
 		"	mcr	p15, 0, %0, c7, c5, 0\n"
-		"	mcr	p15, 0, %0, c7, c10, 4"
+#endif
 		    :
 		    : "r" (0)
 		    : "cc");
+#ifdef CONFIG_ARM_ERRATA_411920
+		v6_icache_inval_all();
+#endif
 	}
 }