ARM: 6886/1: mmc, Add zboot from eSD support for SuperH Mobile ARM

This allows a ROM-able zImage to be written to eSD and for SuperH Mobile
ARM to boot directly from the SDHI hardware block.

This is achieved by the MaskROM 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.

Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: Magnus Damm <magnus.damm@gmail.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 21 insertions, 0 deletions

diff --git a/arch/arm/mach-shmobile/include/mach/sdhi-sh7372.h b/arch/arm/mach-shmobile/include/mach/sdhi-sh7372.h
new file mode 100644
index 000000000000..4a81b01f1e8f
--- /dev/null
+++ b/arch/arm/mach-shmobile/include/mach/sdhi-sh7372.h
@@ -0,0 +1,21 @@
+#ifndef SDHI_SH7372_H
+#define SDHI_SH7372_H
+
+#define SDGENCNTA       0xfe40009c
+
+/* The countdown of SDGENCNTA is controlled by
+ * ZB3D2CLK which runs at 149.5MHz.
+ * That is 149.5ticks/us. Approximate this as 150ticks/us.
+ */
+static void udelay(int us)
+{
+	__raw_writel(us * 150, SDGENCNTA);
+	while(__raw_readl(SDGENCNTA)) ;
+}
+
+static void msleep(int ms)
+{
+	udelay(ms * 1000);
+}
+
+#endif