omap5: Expand CONFIG_SPL_MAX_SIZE and comment upon SRAM_SCRATCH_SPACE_ADDR

After examining both TRMs and doing some experimentation, we can rely on
using the start of the download area for CONFIG_SPL_TEXT_BASE and then
move SRAM_SCRATCH_SPACE_ADDR up, just like am335x.  This is required for
peripheral boot modes such as UART.

Signed-off-by: Tom Rini <trini@ti.com>

arch/arm/include/asm/arch-omap5/omap.h

@@ -153,6 +153,15 @@ struct s32ktimer {
 #define EFUSE_4 0x45145100
 #endif /* __ASSEMBLY__ */
 
+/*
+ * In all cases, the TRM defines the RAM Memory Map for the processor
+ * and indicates the area for the downloaded image.  We use all of that
+ * space for download and once up and running may use other parts of the
+ * map for our needs.  We set a scratch space that is at the end of the
+ * OMAP5 download area, but within the DRA7xx download area (as it is
+ * much larger) and do not, at this time, make use of the additional
+ * space.
+ */
 #ifdef CONFIG_DRA7XX
 #define NON_SECURE_SRAM_START	0x40300000
 #define NON_SECURE_SRAM_END	0x40380000	/* Not inclusive */
@@ -160,7 +169,7 @@ struct s32ktimer {
 #define NON_SECURE_SRAM_START	0x40300000
 #define NON_SECURE_SRAM_END	0x40320000	/* Not inclusive */
 #endif
-#define SRAM_SCRATCH_SPACE_ADDR	NON_SECURE_SRAM_START
+#define SRAM_SCRATCH_SPACE_ADDR	0x4031E000
 
 /* base address for indirect vectors (internal boot mode) */
 #define SRAM_ROM_VECT_BASE	0x4031F000

include/configs/omap5_common.h

@@ -128,8 +128,8 @@
 
 
 /* Defines for SPL */
-#define CONFIG_SPL_TEXT_BASE		0x40300350
-#define CONFIG_SPL_MAX_SIZE		0x19000	/* 100K */
+#define CONFIG_SPL_TEXT_BASE		0x40300000
+#define CONFIG_SPL_MAX_SIZE		(0x4031E000 - CONFIG_SPL_TEXT_BASE)
 #define CONFIG_SPL_DISPLAY_PRINT
 #define CONFIG_SPL_LDSCRIPT "$(CPUDIR)/omap-common/u-boot-spl.lds"