[PATCH v4 2/2] arm: stm32mp: activate data cache on DDR in SPL

[Patrick Delaunay <patrick.delaunay@st.com>]

Activate cache on DDR to improve the accesses to DDR used by SPL:
- CONFIG_SPL_BSS_START_ADDR
- CONFIG_SYS_SPL_MALLOC_START

Cache is configured only when DDR is fully initialized,
to avoid speculative access and issue in get_ram_size().
Data cache is deactivated at the end of SPL, to flush the data cache
and the TLB.

Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
---

Changes in v4:
- fix commit message and add Patrice Chotard reviewed-by

Changes in v3:
- remove debug message "bye"

Changes in v2:
- new

 arch/arm/mach-stm32mp/spl.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/arch/arm/mach-stm32mp/spl.c b/arch/arm/mach-stm32mp/spl.c
index f85391c6af..e50a21c3b7 100644
--- a/arch/arm/mach-stm32mp/spl.c
+++ b/arch/arm/mach-stm32mp/spl.c
@@ -4,6 +4,7 @@
  */
 
 #include <common.h>
+#include <cpu_func.h>
 #include <dm.h>
 #include <hang.h>
 #include <spl.h>
@@ -115,4 +116,22 @@ void board_init_f(ulong dummy)
 		printf("DRAM init failed: %d\n", ret);
 		hang();
 	}
+
+	/*
+	 * activate cache on DDR only when DDR is fully initialized
+	 * to avoid speculative access and issue in get_ram_size()
+	 */
+	if (!CONFIG_IS_ENABLED(SYS_DCACHE_OFF))
+		mmu_set_region_dcache_behaviour(STM32_DDR_BASE, STM32_DDR_SIZE,
+						DCACHE_DEFAULT_OPTION);
+}
+
+void spl_board_prepare_for_boot(void)
+{
+	dcache_disable();
+}
+
+void spl_board_prepare_for_boot_linux(void)
+{
+	dcache_disable();
 }
-- 
2.17.1