ARM: rmobile: Convert Porter to SPL

Due to size limitations of the MERAM, switch U-Boot to SPL.
The SPL is loaded by the SPI_LOADER into MERAM and then loads
U-Boot proper into DRAM. This way U-Boot can freely grow in
size in DRAM, as there is plenty of it.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
---
NOTE: To update U-Boot, first install u-boot.img to 0x140000 in SPI NOR,
      then use the Minimon to flash u-boot-spl.srec using ls,2,e6304000.
      To generate u-boot-spl.srec, use objcopy:
        arm-linux-gnueabi-objcopy -O srec spl/u-boot-spl u-boot-spl.srec
diff --git a/include/configs/porter.h b/include/configs/porter.h
index b4a317f..758ed21 100644
--- a/include/configs/porter.h
+++ b/include/configs/porter.h
@@ -16,12 +16,8 @@
 
 #include "rcar-gen2-common.h"
 
-#if defined(CONFIG_ARCH_RMOBILE_EXTRAM_BOOT)
-#define CONFIG_SYS_INIT_SP_ADDR		0x7023FFFC
-#else
-#define CONFIG_SYS_INIT_SP_ADDR		0xE633fffC
-#endif
-#define STACK_AREA_SIZE			0xC000
+#define CONFIG_SYS_INIT_SP_ADDR		0x4f000000
+#define STACK_AREA_SIZE			0x00100000
 #define LOW_LEVEL_MERAM_STACK \
 		(CONFIG_SYS_INIT_SP_ADDR + STACK_AREA_SIZE - 4)
 
@@ -67,4 +63,11 @@
 
 #define CONFIG_SYS_I2C_POWERIC_ADDR	0x58 /* da9063 */
 
+/* SPL support */
+#define CONFIG_SPL_TEXT_BASE		0xe6304000
+#define CONFIG_SPL_STACK		0xe6340000
+#define CONFIG_SPL_MAX_SIZE		0x40000
+#define CONFIG_SPL_SPI_LOAD
+#define CONFIG_SYS_SPI_U_BOOT_OFFS	0x140000
+
 #endif /* __PORTER_H */