powerpc: mpc85xx: Support booting from SD Card with SPL
The code from the internal on-chip ROM. It loads the final uboot image
into DDR, then jump to it to begin execution.
The SPL's size is sizeable, the maximum size must not exceed the size of L2
SRAM. It initializes the DDR through SPD code, and copys final uboot image
to DDR. So there are two stage uboot images:
* spl_boot, 96KB size. The env variables are copied to L2 SRAM, so that
ddr spd code can get the interleaving mode setting in env. It loads
final uboot image from offset 96KB.
* final uboot image, size is variable depends on the functions enabled.
Signed-off-by: Ying Zhang <b40530@freescale.com>
Acked-by: York Sun <yorksun@freescale.com>
diff --git a/README b/README
index 953ff17..301d1a9 100644
--- a/README
+++ b/README
@@ -3090,6 +3090,10 @@
Support for NAND boot using simple NAND drivers that
expose the cmd_ctrl() interface.
+ CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
+ Set for the SPL on PPC mpc8xxx targets, support for
+ arch/powerpc/cpu/mpc8xxx/ddr/libddr.o in SPL binary.
+
CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,