Add eMMC support.

Author: dgarske

config/examples/polarfire_mpfs250.config

@@ -31,6 +31,10 @@ NO_ARM_ASM?=0
 # Optional: Use smaller SHA512
 #CFLAGS_EXTRA+=-DUSE_SLOW_SHA512
 
+# SDCard (default)
+# Optionally use eMMC
+#CFLAGS+=-DUSE_EMMC
+
 # DDR Address for wolfBoot to start from
 WOLFBOOT_ORIGIN?=0x80000000
 
@@ -45,20 +49,23 @@ WOLFBOOT_LOAD_ADDRESS?=0x8E000000
 WOLFBOOT_NO_PARTITIONS=1
 CFLAGS_EXTRA+=-DBOOT_PART_A=1
 CFLAGS_EXTRA+=-DBOOT_PART_B=2
-# Speed up disk partition read (512KB chunks)
+# Speed up disk partition read (512KB chunks - max DMA size)
 CFLAGS_EXTRA+=-DDISK_BLOCK_SIZE=0x80000
 
 # DTS (Device Tree)
 WOLFBOOT_LOAD_DTS_ADDRESS?=0x8A000000
 
 # Optional Encryption
+#CUSTOM_ENCRYPT_KEY=1
 #ENCRYPT=1
 #ENCRYPT_WITH_AES256=1
+#OBJS_EXTRA=src/my_custom_encrypt_key.o
 
 # Optional EMMC_SD debugging logs
 #CFLAGS_EXTRA+=-DDEBUG_MMC
 # Optional disk debugging logs
 #CFLAGS_EXTRA+=-DDEBUG_DISK
+#CFLAGS_EXTRA+=-DDISK_TEST
 
 # Used by test-application for ELF
 WOLFBOOT_PARTITION_BOOT_ADDRESS=0x80200000