mmc, ARM: Add zboot from eSD support for SuperH Mobile ARM

new file mode 100644
index 0000000..061f22d
@@ -0,0 +1,43 @@
+ROM-able zImage boot from eSD
+-----------------------------
+
+An ROM-able zImage compiled with ZBOOT_ROM_SDHI may be written to eSD and
+SuperH Mobile ARM will to boot directly from the SDHI hardware block.
+
+This is achieved by the mask ROM loading the first portion of the image into
+MERAM and then jumping to it. This portion contains loader code which
+copies the entire image to SDRAM and jumps to it. From there the zImage
+boot code proceeds as normal, uncompressing the image into its final
+location and then jumping to it.
+
+This code has been tested on an mackerel board using the developer 1A eSD
+boot mode which is configured using the following jumper settings.
+
+   8 7 6 5 4 3 2 1
+   x|x|x|x| |x|x|
+S4 -+-+-+-+-+-+-+-
+    | | | |x| | |x on
+
+The eSD card needs to be present in SDHI slot 1 (CN7).
+As such S1 and S33 also need to be configured as per
+the notes in arch/arm/mach-shmobile/board-mackerel.c.
+
+A partial zImage must be written to physical partition #1 (boot)
+of the eSD at sector 0 in vrl4 format. A utility vrl4 is supplied to
+accomplish this.
+
+e.g.
+	vrl4 < zImage | dd of=/dev/sdX bs=512 count=17
+
+A full copy of _the same_ zImage should be written to physical partition #1
+(boot) of the eSD@sector 0. This should _not_ be in vrl4 format.
+
+	vrl4 < zImage | dd of=/dev/sdX bs=512
+
+Note: The commands above assume that the physical partition has been
+switched. No such facility currently exists in the Linux Kernel.
+
+Physical partitions are described in the eSD specification.  At the time of
+writing they are not the same as partitions that are typically configured
+using fdisk and visible through /proc/partitions
+

index 7c0effb..96eb949 100644
@@ -1720,17 +1720,34 @@ config ZBOOT_ROM
 	  Say Y here if you intend to execute your compressed kernel image
 	  (zImage) directly from ROM or flash.  If unsure, say N.
 
+choice
+	prompt "Include SD/MMC loader in zImage (EXPERIMENTAL)"
+	depends on ZBOOT_ROM && ARCH_SH7372 && EXPERIMENTAL
+	default ZBOOT_ROM_NONE
+	help
+	  Include experimental SD/MMC loading code in the ROM-able zImage.
+	  With this enabled it is possible to write the the ROM-able zImage
+	  kernel image to an MMC or SD card and boot the kernel straight
+	  from the reset vector. At reset the processor Mask ROM will load
+	  the first part of the the ROM-able zImage which in turn loads the
+	  rest the kernel image to RAM.
+
+config ZBOOT_ROM_NONE
+	bool "No SD/MMC loader in zImage (EXPERIMENTAL)"
+	help
+	  Do not load image from SD or MMC
+
 config ZBOOT_ROM_MMCIF
 	bool "Include MMCIF loader in zImage (EXPERIMENTAL)"
-	depends on ZBOOT_ROM && ARCH_SH7372 && EXPERIMENTAL
 	help
-	  Say Y here to include experimental MMCIF loading code in the
-	  ROM-able zImage. With this enabled it is possible to write the
-	  the ROM-able zImage kernel image to an MMC card and boot the
-	  kernel straight from the reset vector. At reset the processor
-	  Mask ROM will load the first part of the the ROM-able zImage
-	  which in turn loads the rest the kernel image to RAM using the
-	  MMCIF hardware block.
+	  Load image from MMCIF hardware block.
+
+config ZBOOT_ROM_SH_MOBILE_SDHI
+	bool "Include SuperH Mobile SDHI loader in zImage (EXPERIMENTAL)"
+	help
+	  Load image from SDHI hardware block
+
+endchoice
 
 config CMDLINE
 	string "Default kernel command string"

index 8ebbb51..5249d50 100644
@@ -6,13 +6,19 @@
 
 OBJS		=
 
-# Ensure that mmcif loader code appears early in the image
+# Ensure that MMCIF loader code appears early in the image
 # to minimise that number of bocks that have to be read in
 # order to load it.
 ifeq ($(CONFIG_ZBOOT_ROM_MMCIF),y)
-ifeq ($(CONFIG_ARCH_SH7372),y)
 OBJS		+= mmcif-sh7372.o
 endif
+
+# Ensure that SDHI loader code appears early in the image
+# to minimise that number of bocks that have to be read in
+# order to load it.
+ifeq ($(CONFIG_ZBOOT_ROM_SH_MOBILE_SDHI),y)
+OBJS		+= sdhi-shmobile.o
+OBJS		+= sdhi-sh7372.o
 endif
 
 AFLAGS_head.o += -DTEXT_OFFSET=$(TEXT_OFFSET)

index c943d2e..fe3719b 100644
@@ -25,14 +25,14 @@
 	/* load board-specific initialization code */
 #include <mach/zboot.h>
 
-#ifdef CONFIG_ZBOOT_ROM_MMCIF
-	/* Load image from MMC */
-	adr	sp, __tmp_stack + 128
+#if defined(CONFIG_ZBOOT_ROM_MMCIF) || defined(CONFIG_ZBOOT_ROM_SH_MOBILE_SDHI)
+	/* Load image from MMC/SD */
+	adr	sp, __tmp_stack + 256
 	ldr	r0, __image_start
 	ldr	r1, __image_end
 	subs	r1, r1, r0
 	ldr	r0, __load_base
-	bl	mmcif_loader
+	bl	mmc_loader
 
 	/* Jump to loaded code */
 	ldr	r0, __loaded

@@ -51,9 +51,9 @@ __loaded:
 	.long	__continue
 	.align
 __tmp_stack:
-	.space	128
+	.space	256
 __continue:
-#endif /* CONFIG_ZBOOT_ROM_MMCIF */
+#endif /* CONFIG_ZBOOT_ROM_MMC || CONFIG_ZBOOT_ROM_SH_MOBILE_SDHI */
 
 	b	1f
 __atags:@ tag #1