rockchip: add sdram_common for common functions
There are some functions like sdram_size_mb can be re-used for
different rockchip SoCs, just put them into common file.
Add board_get_usable_ram_top() for ram_top init base on
SDRAM_MAX_SIZE.
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Added SDRAM_MAX_SIZE definition for RK3036:
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
fixup: 3036 fix for sdram_common
diff --git a/include/configs/rk3399_common.h b/include/configs/rk3399_common.h
index 44dad57..54ea97b 100644
--- a/include/configs/rk3399_common.h
+++ b/include/configs/rk3399_common.h
@@ -51,6 +51,7 @@
/* FAT sd card locations. */
#define CONFIG_SYS_MMCSD_FS_BOOT_PARTITION 1
#define CONFIG_SYS_SDRAM_BASE 0
+#define SDRAM_MAX_SIZE 0xf8000000
#define CONFIG_NR_DRAM_BANKS 1
#define CONFIG_SF_DEFAULT_SPEED 20000000