HI,

 

I am working on linux kernel MMC layer which is responsible for supporting SD/MMC cards on ARM platform. I am stuck with an issue related to TI OMAP driver in this layer.

Background of Problem - OMAP is not SDHCI compliant

In the mmc linux kernel driver stack, most of the drivers are sdhci compilant.

All sdhci compliant drivers have a common code which is written in sdhci.c and a specific hardware dependent code which are present is files like tegra-sdhci.c for NVIDIA Tegra and sdhci-esdhc for Freescale iMX. 

For NVIDIA Tegra -

For Freescale iMX –

Since the present omap_hsmmc driver as of now is not sdhci complaint, it does all these tasks by itself as shown in the below link –

I need to get memory mapping of registers right. What I found was that the memory mapping defined in the SDHCI was not same as that of omap.

So I wrote to TI but he said the registers are mapping, even the offsets are same.

He gave me the example of these two registers from am335x TRM here-

From 18.5.1.10 in AM335x TRM:

SD_CMD[31:16] = the command register. SD_CMD[15:0] = the transfer mode

From 18.5.1.17

 SD_HCTL[23:16] = Block gap control.

In the SDHCI spec given here -

https://www.sdcard.org/downloads/pls/simplified_specs/archive/partA2_300.pdf

 these registers are having these memory address/offsets -

 

I am not able to figure out how these offsets are same. Can someone help me regarding this.

Regards,

Saket Sinha