SDHC driver of RTEMS

[ruizx]

>> 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.
>> 
>> 
>> 
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>> rtems-users mailing list
>> rtems-users at rtems.org
>> http://www.rtems.org/mailman/listinfo/rtems-users
> 
> Hi, I had played with SDHC with AT91RM9200 some time ago.
> I port (see attachment) mixed source code from Linux and U-Boot and
> it works very well with RTEMS FAT filesystem. To use this code you
> need implement device support structure mmc_device and replace
> mci_mmc_device with it. Unfortunately this code is under GPLv2 and
> can't be included in RTEMS.  
> If someone need help for native MMC stack implementation for RTEMS I
> can spend some time. 

Thanks Andrey, the driver looks like a mixer of Linux and U-Boot :)
I'll try to find the differece between the driver and my code.
I find that this driver not using multi-block access, just single block access.
Do you notice this? Or issue in it?