SDHC driver of RTEMS

Mozzhuhin Andrey amozzhuhin at
Mon Aug 5 12:51:12 UTC 2013

On 03.08.2013 05:41, 芮正新 wrote:
> 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,
> Anyone can give me some help for the SDHC driver? Very thanks to you.
> _______________________________________________
> rtems-users mailing list
> rtems-users at

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.
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