From 28278839116d9e29132a61c2c0c612900c244708 Mon Sep 17 00:00:00 2001
From: Sascha Hauer <s.hauer@pengutronix.de>
Date: Wed, 15 May 2013 21:11:47 +0200
Subject: [PATCH] ARM: invalidate data caches during early init

Some SoCs come up with invalid entries in the data cache. This can
lead to memory corruption when we enable them later, so invalidate
the caches early.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Lucas Stach <l.stach@pengutronix.de>
---
 arch/arm/cpu/cache.c         | 21 +++++++++++++++++++++
 arch/arm/cpu/start-pbl.c     |  2 ++
 arch/arm/cpu/start.c         |  2 ++
 arch/arm/include/asm/cache.h |  5 +++++
 4 files changed, 30 insertions(+)

diff --git a/arch/arm/cpu/cache.c b/arch/arm/cpu/cache.c
index 95c833825..7aab55b6b 100644
--- a/arch/arm/cpu/cache.c
+++ b/arch/arm/cpu/cache.c
@@ -134,3 +134,24 @@ void arm_early_mmu_cache_flush(void)
 #endif
 	}
 }
+
+void v7_mmu_cache_invalidate(void);
+
+void arm_early_mmu_cache_invalidate(void)
+{
+	switch (arm_early_get_cpu_architecture()) {
+	case CPU_ARCH_ARMv4T:
+	case CPU_ARCH_ARMv5:
+	case CPU_ARCH_ARMv5T:
+	case CPU_ARCH_ARMv5TE:
+	case CPU_ARCH_ARMv5TEJ:
+	case CPU_ARCH_ARMv6:
+		asm volatile("mcr p15, 0, %0, c7, c6, 0\n" : : "r"(0));
+		return;
+#ifdef CONFIG_CPU_32v7
+	case CPU_ARCH_ARMv7:
+		v7_mmu_cache_invalidate();
+		return;
+#endif
+	}
+}
diff --git a/arch/arm/cpu/start-pbl.c b/arch/arm/cpu/start-pbl.c
index 6f03c4a7d..3ef011852 100644
--- a/arch/arm/cpu/start-pbl.c
+++ b/arch/arm/cpu/start-pbl.c
@@ -59,6 +59,8 @@ static noinline __noreturn void __barebox_arm_entry(uint32_t membase,
 
 	endmem -= STACK_SIZE; /* stack */
 
+	arm_early_mmu_cache_invalidate();
+
 	if (IS_ENABLED(CONFIG_PBL_RELOCATABLE))
 		relocate_to_current_adr();
 
diff --git a/arch/arm/cpu/start.c b/arch/arm/cpu/start.c
index 580c1fed2..5a3c629c7 100644
--- a/arch/arm/cpu/start.c
+++ b/arch/arm/cpu/start.c
@@ -124,6 +124,8 @@ void __naked __noreturn barebox_arm_entry(uint32_t membase, uint32_t memsize,
 {
 	arm_setup_stack(membase + memsize - 16);
 
+	arm_early_mmu_cache_invalidate();
+
 	__start(membase, memsize, boarddata);
 }
 #else
diff --git a/arch/arm/include/asm/cache.h b/arch/arm/include/asm/cache.h
index e5621ebbc..f5f8bf387 100644
--- a/arch/arm/include/asm/cache.h
+++ b/arch/arm/include/asm/cache.h
@@ -10,10 +10,15 @@ int arm_set_cache_functions(void);
 
 #ifdef CONFIG_MMU
 void arm_early_mmu_cache_flush(void);
+void arm_early_mmu_cache_invalidate(void);
 #else
 static inline void arm_early_mmu_cache_flush(void)
 {
 }
+
+static inline void arm_early_mmu_cache_invalidate(void)
+{
+}
 #endif
 
 #endif