ARM: 8496/1: OMAP: RX51: save ATAGS data in the early boot stage

This fixes a regression with device tree based booting compared to legacy booting for n900 to make the n900 legacy user space to also work with device tree based booting
Signed-off-by: NIvaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-omap2/board-generic.c

@@ -16,6 +16,7 @@
 #include <linux/of_platform.h>
 #include <linux/irqdomain.h>
 
+#include <asm/setup.h>
 #include <asm/mach/arch.h>
 
 #include "common.h"
@@ -76,8 +77,17 @@ static const char *const n900_boards_compat[] __initconst = {
 	NULL,
 };
 
+/* Legacy userspace on Nokia N900 needs ATAGS exported in /proc/atags,
+ * save them while the data is still not overwritten
+ */
+static void __init rx51_reserve(void)
+{
+	save_atags((const struct tag *)(PAGE_OFFSET + 0x100));
+	omap_reserve();
+}
+
 DT_MACHINE_START(OMAP3_N900_DT, "Nokia RX-51 board")
-	.reserve	= omap_reserve,
+	.reserve	= rx51_reserve,
 	.map_io		= omap3_map_io,
 	.init_early	= omap3430_init_early,
 	.init_machine	= omap_generic_init,