[PATCH v3] arm/xilinx_zynq: Disable the MMU and the data and instruction cache on boot.

[Chris Johns]

The u-boot loader can enable the MMU plus the data and instruction caches.
Disable them and if the data cache is enabled clear it before turn the caches off.

Closes #2774.
---
 c/src/lib/libbsp/arm/shared/include/arm-cp15-start.h   | 4 ++++
 c/src/lib/libbsp/arm/xilinx-zynq/startup/bspstartmmu.c | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/c/src/lib/libbsp/arm/shared/include/arm-cp15-start.h b/c/src/lib/libbsp/arm/shared/include/arm-cp15-start.h
index 01fdbb3..7734ddc 100644
--- a/c/src/lib/libbsp/arm/shared/include/arm-cp15-start.h
+++ b/c/src/lib/libbsp/arm/shared/include/arm-cp15-start.h
@@ -166,6 +166,10 @@ arm_cp15_start_setup_mmu_and_cache(uint32_t ctrl_clear, uint32_t ctrl_set)
 {
   uint32_t ctrl = arm_cp15_get_control();
 
+  if ((ctrl & ARM_CP15_CTRL_C) != 0) {
+    arm_cp15_data_cache_clean_all_levels();
+  }
+
   ctrl &= ~ctrl_clear;
   ctrl |= ctrl_set;
 
diff --git a/c/src/lib/libbsp/arm/xilinx-zynq/startup/bspstartmmu.c b/c/src/lib/libbsp/arm/xilinx-zynq/startup/bspstartmmu.c
index c7a1089..0918588 100644
--- a/c/src/lib/libbsp/arm/xilinx-zynq/startup/bspstartmmu.c
+++ b/c/src/lib/libbsp/arm/xilinx-zynq/startup/bspstartmmu.c
@@ -41,7 +41,7 @@ BSP_START_TEXT_SECTION void zynq_setup_mmu_and_cache(void) __attribute__ ((weak)
 BSP_START_TEXT_SECTION void zynq_setup_mmu_and_cache(void)
 {
   uint32_t ctrl = arm_cp15_start_setup_mmu_and_cache(
-    ARM_CP15_CTRL_A,
+    ARM_CP15_CTRL_A | ARM_CP15_CTRL_C | ARM_CP15_CTRL_I | ARM_CP15_CTRL_M,
     ARM_CP15_CTRL_AFE | ARM_CP15_CTRL_Z
   );
 
-- 
2.4.6