refactor(plat/allwinner): allow custom BL31 offset

Not all Allwinner SoCs have the same arrangement to SRAM A2.

Allow to specify a offset at which BL31 will stay in SRAM A2.

Change-Id: I574140ffd704a796fae0a5c2d0976e85c7fcbdf9
Signed-off-by: Icenowy Zheng <icenowy@sipeed.com>

plat/allwinner/common/include/platform_def.h

@@ -25,7 +25,8 @@
 
 #else	/* !SUNXI_BL31_IN_DRAM */
 
-#define BL31_BASE			(SUNXI_SRAM_A2_BASE + 0x4000)
+#define BL31_BASE			(SUNXI_SRAM_A2_BASE + \
+					 SUNXI_SRAM_A2_BL31_OFFSET)
 #define BL31_LIMIT			(SUNXI_SRAM_A2_BASE + \
 					 SUNXI_SRAM_A2_SIZE - SUNXI_SCP_SIZE)
 

plat/allwinner/sun50i_a64/include/sunxi_mmap.h

@@ -15,6 +15,7 @@
 #define SUNXI_SRAM_A1_BASE		0x00010000
 #define SUNXI_SRAM_A1_SIZE		0x00008000
 #define SUNXI_SRAM_A2_BASE		0x00040000
+#define SUNXI_SRAM_A2_BL31_OFFSET	0x00004000
 #define SUNXI_SRAM_A2_SIZE		0x00014000
 #define SUNXI_SRAM_C_BASE		0x00018000
 #define SUNXI_SRAM_C_SIZE		0x0001c000

plat/allwinner/sun50i_h6/include/sunxi_mmap.h

@@ -15,6 +15,7 @@
 #define SUNXI_SRAM_A1_BASE		0x00020000
 #define SUNXI_SRAM_A1_SIZE		0x00008000
 #define SUNXI_SRAM_A2_BASE		0x00100000
+#define SUNXI_SRAM_A2_BL31_OFFSET	0x00004000
 #define SUNXI_SRAM_A2_SIZE		0x00018000
 #define SUNXI_SRAM_C_BASE		0x00028000
 #define SUNXI_SRAM_C_SIZE		0x0001e000