From: Vikas Manocha <vikas.manocha@st.com>
Date: Wed, 3 May 2017 22:48:26 +0000 (-0700)
Subject: arvm7m: add cleanup before linux booting
X-Git-Tag: v2017.07-rc1~333
X-Git-Url: https://git.sur5r.net/?a=commitdiff_plain;h=4098d2061ff57b731e195abe03a0b73ac69c8689;p=u-boot

arvm7m: add cleanup before linux booting

Data cache memory needs to be disabled before handing over control to
linux kernel. This patch populates the cleanup_before_linux stub.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
---

diff --git a/arch/arm/cpu/armv7m/cpu.c b/arch/arm/cpu/armv7m/cpu.c
index 58cde9391f..a424babde5 100644
--- a/arch/arm/cpu/armv7m/cpu.c
+++ b/arch/arm/cpu/armv7m/cpu.c
@@ -18,6 +18,25 @@
  */
 int cleanup_before_linux(void)
 {
+	/*
+	 * this function is called just before we call linux
+	 * it prepares the processor for linux
+	 *
+	 * disable interrupt and turn off caches etc ...
+	 */
+	disable_interrupts();
+	/*
+	 * turn off D-cache
+	 * dcache_disable() in turn flushes the d-cache
+	 * MPU is still enabled & can't be disabled as the u-boot
+	 * code might be running in sdram which by default is not
+	 * executable area.
+	 */
+	dcache_disable();
+	/* invalidate to make sure no cache line gets dirty between
+	 * dcache flushing and disabling dcache */
+	invalidate_dcache_all();
+
 	return 0;
 }