[PATCH 2/6] ARM: add early mmu cache flush function and use it in setup_c

[Sascha Hauer]

Since recently with MMU_EARLY support it may happen that setup_c
runs with data caches enabled, so we have to make sure the caches
are flushed before we jump to the new binary.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 arch/arm/cpu/cache.c         | 33 +++++++++++++++++++++++++++++++++
 arch/arm/cpu/setupc.S        |  3 +++
 arch/arm/include/asm/cache.h |  8 ++++++++
 3 files changed, 44 insertions(+)

diff --git a/arch/arm/cpu/cache.c b/arch/arm/cpu/cache.c
index 1254609..95c8338 100644
--- a/arch/arm/cpu/cache.c
+++ b/arch/arm/cpu/cache.c
@@ -101,3 +101,36 @@ int arm_set_cache_functions(void)
 
 	return 0;
 }
+
+/*
+ * Early function to flush the caches. This is for use when the
+ * C environment is not yet fully initialized.
+ */
+void arm_early_mmu_cache_flush(void)
+{
+	switch (arm_early_get_cpu_architecture()) {
+#ifdef CONFIG_CPU_32v4T
+	case CPU_ARCH_ARMv4T:
+		v4_mmu_cache_flush();
+		return;
+#endif
+#ifdef CONFIG_CPU_32v5
+	case CPU_ARCH_ARMv5:
+	case CPU_ARCH_ARMv5T:
+	case CPU_ARCH_ARMv5TE:
+	case CPU_ARCH_ARMv5TEJ:
+		v5_mmu_cache_flush();
+		return;
+#endif
+#ifdef CONFIG_CPU_32v6
+	case CPU_ARCH_ARMv6:
+		v6_mmu_cache_flush();
+		return;
+#endif
+#ifdef CONFIG_CPU_32v7
+	case CPU_ARCH_ARMv7:
+		v7_mmu_cache_flush();
+		return;
+#endif
+	}
+}
diff --git a/arch/arm/cpu/setupc.S b/arch/arm/cpu/setupc.S
index 9a8d54c..d0de87d 100644
--- a/arch/arm/cpu/setupc.S
+++ b/arch/arm/cpu/setupc.S
@@ -26,6 +26,9 @@ ENTRY(setup_c)
 	ldr	r2, =__bss_stop
 	sub	r2, r2, r0
 	bl	memset			/* clear bss */
+#ifdef CONFIG_MMU
+	bl	arm_early_mmu_cache_flush
+#endif
 	mov	r0, #0
 	mcr	p15, 0, r0, c7, c5, 0	/* flush icache */
 	add	lr, r5, r4		/* adjust return address to new location */
diff --git a/arch/arm/include/asm/cache.h b/arch/arm/include/asm/cache.h
index d5877ff..e5621eb 100644
--- a/arch/arm/include/asm/cache.h
+++ b/arch/arm/include/asm/cache.h
@@ -8,4 +8,12 @@ static inline void flush_icache(void)
 
 int arm_set_cache_functions(void);
 
+#ifdef CONFIG_MMU
+void arm_early_mmu_cache_flush(void);
+#else
+static inline void arm_early_mmu_cache_flush(void)
+{
+}
+#endif
+
 #endif
-- 
1.8.2.rc2