OMAP: Store reboot mode in scratchpad on OMAP34xx

The reboot mode can be communicated to a bootloader (or the
kernel itself) with a scratchpad register. This functionality
is especially useful, if userspace is allowed to change
the reboot mode.

Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

arch/arm/mach-omap2/prcm.c

@@ -135,9 +135,18 @@ void omap_prcm_arch_reset(char mode)
 
 	if (cpu_is_omap24xx())
 		prcm_offs = WKUP_MOD;
-	else if (cpu_is_omap34xx())
+	else if (cpu_is_omap34xx()) {
+		u32 l;
+
 		prcm_offs = OMAP3430_GR_MOD;
-	else
+		l = ('B' << 24) | ('M' << 16) | mode;
+		/* Reserve the first word in scratchpad for communicating
+		 * with the boot ROM. A pointer to a data structure
+		 * describing the boot process can be stored there,
+		 * cf. OMAP34xx TRM, Initialization / Software Booting
+		 * Configuration. */
+		omap_writel(l, OMAP343X_SCRATCHPAD + 4);
+	} else
 		WARN_ON(1);
 
 	prm_set_mod_reg_bits(OMAP_RST_DPLL3, prcm_offs, RM_RSTCTRL);