ARM: give boards control of the reset entry point

On some SoCs (for example AM35xx), the ROM bootloader passes useful
information in r0 when jumping to barebox.

To avoid overwriting this in the generic reset code, we introduce
common_reset as a C function and as an assembler macro. This is then
called form the reset entry point (either in common or in board code).

This patch is based on code by Sascha Hauer <s.hauer@pengutronix.de>.

Signed-off-by: Jan Luebbe <jlu@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 12 insertions, 0 deletions

diff --git a/arch/arm/cpu/start-pbl.c b/arch/arm/cpu/start-pbl.c
index 932a3da9e2..823b9ccebc 100644
--- a/arch/arm/cpu/start-pbl.c
+++ b/arch/arm/cpu/start-pbl.c
@@ -41,6 +41,18 @@ void __naked __section(.text_head_entry) pbl_start(void)
 	barebox_arm_head();
 }
 
+/*
+ * The actual reset vector. This code is position independent and usually
+ * does not run at the address it's linked at.
+ */
+#ifndef CONFIG_MACH_DO_LOWLEVEL_INIT
+void __naked __bare_init reset(void)
+{
+	common_reset();
+	board_init_lowlevel_return();
+}
+#endif
+
 extern void *input_data;
 extern void *input_data_end;