1ROM-able zImage boot from MMC 2----------------------------- 3 4An ROM-able zImage compiled with ZBOOT_ROM_MMCIF may be written to MMC and 5SuperH Mobile ARM will to boot directly from the MMCIF hardware block. 6 7This is achieved by the mask ROM loading the first portion of the image into 8MERAM and then jumping to it. This portion contains loader code which 9copies the entire image to SDRAM and jumps to it. From there the zImage 10boot code proceeds as normal, uncompressing the image into its final 11location and then jumping to it. 12 13This code has been tested on an AP4EB board using the developer 1A eMMC 14boot mode which is configured using the following jumper settings. 15The board used for testing required a patched mask ROM in order for 16this mode to function. 17 18 8 7 6 5 4 3 2 1 19 x|x|x|x|x| |x| 20S4 -+-+-+-+-+-+-+- 21 | | | | |x| |x on 22 23The zImage must be written to the MMC card at sector 1 (512 bytes) in 24vrl4 format. A utility vrl4 is supplied to accomplish this. 25 26e.g. 27 vrl4 < zImage | dd of=/dev/sdX bs=512 seek=1 28 29A dual-voltage MMC 4.0 card was used for testing. 30