Hi Paco. Problem is because of mmc_over_gpio loads mmc_spi when installing. So mmc_over_gpio does not work.

Good news everyone It is not exactly what we have been expecting, but still some progress. We managed to deal with M25P64 8MB SPI flash connected to hardware SPI interface. Check this link

Good news indeed! This shouldn't be much different from an SD/MMC card, right? How is the performance? And is there any way we can help to improve the implementation?

So far driver has some issues and speed is very low (~50kb/s). But at least it works.

Hi Saulius

I saw some discussions on other threads ( viewtopic.php?f=7&t=31 ) regarding other versions of Carambola (one with RT 3352 ) and eventually booting from SD.

While these are great news, we'd really keen to know if there have any advances in terms of enabling SD card support on Carambola.

We're really keen to start porting our projects to Carambola but the absence of microSD with reasonable performance (let's say ~1mbps) is unfortunately a big show stopper for us.

Can you share some more technical details about the current solution so far?
- What was modified in the files specifically for Carambola?
- Is this the Real mode driver or is it still the Emulated driver?

Thanks
Pedro

Robosavvy, we are a bit stuck where SPI/SD module tries communicating with card. Card even responds back but looks like Carambola does not understands it. If we are lucky I hope to get my hands on this issue this weekend.

Some key files:
build_dir/linux-ramips_rt305x/linux-2.6.39.4/arch/mips/ralink/rt305x/mach-carambola.c
target/linux/ramips/files/arch/mips/ralink/rt305x/rt305x.c
build_dir/linux-ramips_rt305x/linux-2.6.39.4/drivers/mmc/host/mmc_spi.c
build_dir/linux-ramips_rt305x/linux-2.6.39.4/drivers/mmc/core/core.c
build_dir/linux-ramips_rt305x/linux-2.6.39.4/drivers/spi/ramips_spi.c
build_dir/linux-ramips_rt305x/linux-2.6.39.4/drivers/spi/spi.c

And yes, it is hardware driver, not emulation.

And one more note - Carambola does not have any possibility to boot from SD card.

Worst case scenario, if you really really must have SD card, you can temporary use USB-SD card reader.

--
Saulius

Hi there,

is there any news on using an SD card through the SPI? I know there have been some work and success with a FLASH chip but 8 or even 16Mb are not enough for my application.

Good work.

I soldered a SD adapter to use a micro-SD and succeeded using mmc-over-gpio and also it can be configured using LUCI just including the module in the LUCI section of the menuconfig.
I haven't checked CPU usage but throughput is slow, not unusable but slow.
I'm looking into the code of the mmc-over-gpio source to find if there's any room for improvement. I doubt it but...
I haven't formatted the card, it's a 4GB SDHC kingston recognized as VFAT, I suppose it's FAT32.

I mount it and also copy some files in it.
/dev/mmcblk0p1 /mnt/mmc 3.63 GB / 3.63 GB 0% (32.00 KB)

these are the kernel messages

[ 38.350000] gpio-mmc: Failed to request mmc_spi module.
[ 38.380000] mmc_spi spi32766.0: ASSUMING 3.2-3.4 V slot power
[ 38.390000] mmc_spi spi32766.0: SD/MMC host mmc0, no DMA, no WP, no poweroff
[ 38.390000] gpio-mmc: MMC-Card "default" attached to GPIO pins di=11, do=9, clk=12, cs=13
[ 41.430000] mmc_spi spi32766.0: setup: unsupported mode bits 4
[ 41.430000] mmc_spi spi32766.0: can't change chip-select polarity
[ 41.580000] mmc0: host does not support reading read-only switch. assuming write-enable.
[ 41.590000] mmc0: new SDHC card on SPI
[ 41.600000] mmcblk0: mmc0:0000 SA04G 3.63 GiB
[ 41.650000] mmcblk0: p1