We're working on a custom board using the iMX287 processor and are having trouble getting the SD/MMC card to be recognized by the Linux kernel at higher MMC clock rates. We started with the hardware design from the HEG and are trying to atapt the software from the EVK, duplicating the settings for SSP2 from SSP0 and SSP1. U-Boot sees the card and seems to display the correct device and partition information. However once the kernel is booted entries for the MMC partions only show up in the /Dev directory if we slow the interface clock rate down to ~1MHz. At 1MHz the card operates in both 1 and 4 bit modes, at 2MHz only the 1 bit mode operates, and at 4MHz nothing functions. The first suspicion is that there is a hardware timing issue but everything seems to be consistent with that of the EVK.
Has anyone sucessfully implmented a SD/MMC card on SSP2?
Is SSP2 treated differently from SSP0 or SSP1 with repsect to the SD/MMC interface?
Is there something in the EVK configuration that might, inadvertantly, be causing our problems, i.e. incorrect DMA settings?
Any thoughts would be appreciated, thanks in advance,