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Commit | Line | Data |
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f45b1149 SH |
1 | ROM-able zImage boot from MMC |
2 | ----------------------------- | |
3 | ||
4 | An ROM-able zImage compiled with ZBOOT_ROM_MMCIF may be written to MMC and | |
5 | SuperH Mobile ARM will to boot directly from the MMCIF hardware block. | |
6 | ||
7 | This is achieved by the mask ROM loading the first portion of the image into | |
8 | MERAM and then jumping to it. This portion contains loader code which | |
9 | copies the entire image to SDRAM and jumps to it. From there the zImage | |
10 | boot code proceeds as normal, uncompressing the image into its final | |
11 | location and then jumping to it. | |
12 | ||
13 | This code has been tested on an AP4EB board using the developer 1A eMMC | |
14 | boot mode which is configured using the following jumper settings. | |
15 | The board used for testing required a patched mask ROM in order for | |
16 | this mode to function. | |
17 | ||
18 | 8 7 6 5 4 3 2 1 | |
19 | x|x|x|x|x| |x| | |
20 | S4 -+-+-+-+-+-+-+- | |
21 | | | | | |x| |x on | |
22 | ||
23 | The zImage must be written to the MMC card at sector 1 (512 bytes) in | |
24 | vrl4 format. A utility vrl4 is supplied to accomplish this. | |
25 | ||
26 | e.g. | |
27 | vrl4 < zImage | dd of=/dev/sdX bs=512 seek=1 | |
28 | ||
29 | A dual-voltage MMC 4.0 card was used for testing. |