omap3: Reboot mode support

Reboot mode is written in scratchpad memory before reboot in the form of a
single char, that is the first letter of the reboot mode string as passed to the
reboot function.

This mechanism is supported on OMAP3 both my the upstream kernel and by various
TI kernels.

It is up to each board to make use of this mechanism or not.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Reviewed-by: Tom Rini <trini@konsulko.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/arch/arm/cpu/armv7/omap3/boot.c b/arch/arm/cpu/armv7/omap3/boot.c
index 66576b26c5..44d7c30662 100644
--- a/arch/arm/cpu/armv7/omap3/boot.c
+++ b/arch/arm/cpu/armv7/omap3/boot.c
@@ -56,3 +56,41 @@ u32 omap_sys_boot_device(void)
 
 	return boot_devices[sys_boot];
 }
+
+char omap_reboot_mode(void)
+{
+	u32 reboot_mode;
+	char c;
+
+	reboot_mode = readl((u32 *)(OMAP34XX_SCRATCHPAD + 4));
+
+	c = (reboot_mode >> 24) & 0xff;
+	if (c != 'B')
+		return -1;
+
+	c = (reboot_mode >> 16) & 0xff;
+	if (c != 'M')
+		return -1;
+
+	c = reboot_mode & 0xff;
+
+	return c;
+}
+
+int omap_reboot_mode_clear(void)
+{
+	writel(0, (u32 *)(OMAP34XX_SCRATCHPAD + 4));
+
+	return 0;
+}
+
+int omap_reboot_mode_store(char c)
+{
+	u32 reboot_mode;
+
+	reboot_mode = 'B' << 24 | 'M' << 16 | c;
+
+	writel(reboot_mode, (u32 *)(OMAP34XX_SCRATCHPAD + 4));
+
+	return 0;
+}