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- ROM-able zImage boot from MMC
- -----------------------------
- An ROM-able zImage compiled with ZBOOT_ROM_MMCIF may be written to MMC and
- SuperH Mobile ARM will to boot directly from the MMCIF 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 AP4EB board using the developer 1A eMMC
- boot mode which is configured using the following jumper settings.
- The board used for testing required a patched mask ROM in order for
- this mode to function.
- 8 7 6 5 4 3 2 1
- x|x|x|x|x| |x|
- S4 -+-+-+-+-+-+-+-
- | | | | |x| |x on
- The zImage must be written to the MMC card at sector 1 (512 bytes) in
- vrl4 format. A utility vrl4 is supplied to accomplish this.
- e.g.
- vrl4 < zImage | dd of=/dev/sdX bs=512 seek=1
- A dual-voltage MMC 4.0 card was used for testing.
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