26 Mar
2017
26 Mar
'17
1:06 a.m.
It turns out that all linux images we've used so far had no support yet for UHS or HS200 or such in the MMC driver, hence the primary SD slot and eMMC were artificially speed-limited.
It turned out patches to fix that had been made but have not yet reached upstream. I've rebased them on top of mainline 4.10.1: https://github.com/mvduin/linux/commits/ti/omap-hsmmc
All you then need to do is declare supported functionality in DT: https://github.com/mvduin/linux/commit/925d93d4e22a
As a bonus they also enhanced DMA support.
Read speed on the eMMC of the uEVM about 60-65 MB/s.
Enjoy!
Matthijs