[PATCH 05/20] nommu_v7_vectors_init: disable for r5

[Sascha Hauer]

Some ARMv7 cores like the Cortex-R5 do not have a VBAR register for
setting up the vector table. This patch disables the vector table
setup specifically for the Cortex-R5.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 arch/arm/cpu/no-mmu.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/arm/cpu/no-mmu.c b/arch/arm/cpu/no-mmu.c
index be3cfaf12b..c4ef5d1f9d 100644
--- a/arch/arm/cpu/no-mmu.c
+++ b/arch/arm/cpu/no-mmu.c
@@ -19,9 +19,26 @@
 #include <asm/system_info.h>
 #include <debug_ll.h>
 #include <asm/sections.h>
+#include <asm/cputype.h>
 
 #define __exceptions_size (__exceptions_stop - __exceptions_start)
 
+static bool has_vbar(void)
+{
+	u32 mainid;
+
+	__asm__ __volatile__(
+		"mrc    p15, 0, %0, c0, c0, 0   @ read control reg\n"
+		: "=r" (mainid)
+		:
+		: "memory");
+
+	if ((mainid & 0xfff0) == ARM_CPU_PART_CORTEX_R5)
+		return false;
+
+	return true;
+}
+
 static int nommu_v7_vectors_init(void)
 {
 	void *vectors;
@@ -30,6 +47,9 @@ static int nommu_v7_vectors_init(void)
 	if (cpu_architecture() < CPU_ARCH_ARMv7)
 		return 0;
 
+	if (!has_vbar())
+		return 0;
+
 	/*
 	 * High vectors cannot be re-mapped, so we have to use normal
 	 * vectors

-- 
2.39.5