[U-Boot] [PATCH v2] mx25: Fix boot hang by avoiding vector relocation

[Fabio Estevam <festevam@gmail.com>]

From: Fabio Estevam <fabio.estevam@freescale.com>

Since commit 3ff46cc42b9d73d0 ("arm: relocate the exception vectors") mx25pdk
hangs like this:

CPU:   Freescale i.MX25 rev1.2 at 399 MHz
Reset cause: WDOG
Board: MX25PDK
I2C:   ready
DRAM:  64 MiB
(hangs)

Add a specific relocate_vectors macro that skips the vector relocation, as the 
i.MX25 SoC does not provide RAM at the high vectors address (0xFFFF0000), and
(0x00000000) maps to ROM.

This allows mx25 to boot again.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
Changes since v1:
- Skip the vector relocation on mx25

 arch/arm/cpu/arm926ejs/mx25/Makefile   |  4 ++++
 arch/arm/cpu/arm926ejs/mx25/relocate.S | 23 +++++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 arch/arm/cpu/arm926ejs/mx25/relocate.S

diff --git a/arch/arm/cpu/arm926ejs/mx25/Makefile b/arch/arm/cpu/arm926ejs/mx25/Makefile
index 134c69d..ebc0407 100644
--- a/arch/arm/cpu/arm926ejs/mx25/Makefile
+++ b/arch/arm/cpu/arm926ejs/mx25/Makefile
@@ -5,3 +5,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 
 obj-y	= generic.o timer.o reset.o
+
+ifndef CONFIG_SPL_BUILD
+obj-y	+= relocate.o
+endif
diff --git a/arch/arm/cpu/arm926ejs/mx25/relocate.S b/arch/arm/cpu/arm926ejs/mx25/relocate.S
new file mode 100644
index 0000000..8ebb81f
--- /dev/null
+++ b/arch/arm/cpu/arm926ejs/mx25/relocate.S
@@ -0,0 +1,23 @@
+/*
+ *  relocate - i.MX25-specific vector relocation
+ *
+ *  Copyright (c) 2013  Albert ARIBAUD <albert.u.boot@aribaud.net>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <linux/linkage.h>
+
+/*
+ * The i.MX25 SoC is very specific with respect to exceptions: it
+ * does not provide RAM at the high vectors address (0xFFFF0000),
+ * thus only the low address (0x00000000) is useable; but that is
+ * in ROM, so let's avoid relocating the vectors.
+ */
+	.section	.text.relocate_vectors,"ax",%progbits
+
+ENTRY(relocate_vectors)
+
+	bx	lr
+
+ENDPROC(relocate_vectors)
-- 
1.9.1