SDHC driver of RTEMS

[芮正新]

Hi all,
I want to use SDHC SD card on my MPC8309SOM board.
RTEMS not include the SDHC driver, so I try to port the SDHC driver from u-boot code, but it seem to have too many problems.
When I set CONFIGURE_BDBUF_MAX_READ_AHEAD_BLOCKS >1, the driver can't work well.
The BRDA task looks like be blocked after read the number of CONFIGURE_BDBUF_BUFFER_MAX_SIZE blocks, and some seconds later, the fread function return error.
The fwrite function often failed.
I searched the web and know that P1020 also has SDHC,
http://www.rtems.com/wiki/index.php/QorIQ.

Anyone can give me some help for the SDHC driver? Very thanks to you.