On 21 July 2016 at 13:17, Haojian Zhuang <haojian.zhu...@linaro.org> wrote: > On 2016/7/21 9:52, Haojian Zhuang wrote: >> >> >> >> 在 07/21/2016 09:51 AM, Haojian Zhuang 写道: >>> >>> Hi Feng, >>> >>> I think the main difference is who to handle the CRC bits. In the >>> designware emmc/sd controller, the whole 128-bit value is loaded into >>> the four response registers. There's no any shift on the 128-bit value >>> to remove CRC. (Refer to: drivers/mmc/host/dw_mmc.c). >> >> >> I mean the implementation in linux. $Linux/drivers/mmc/host/dw_mmc.c >> >>> >>> In the eMMC spec, it only mentions R2 response in table. >>> >>> Bit position [127:1] >>> Width (bits) 127 >>> Value x >>> Description CID or CSD register incl. >>> internal CRC7 >>> It also doesn't mention that we need to shift response value for CSD >>> register. >>> >>> So I did this fixing patch. I think that shifting isn't common to >>> support all eMMC/SD controller IP. Without this patch, the eMMC stack >>> will only get shifted CSD register value. >>> It results in parse error. > > > As I checked the SDHC driver in linux, there's the same logic as you > implemented in EmmcDxe. > > Now the question is whether EmmcDxe is designed for common code of all > vendor's IP. If so, we need to provide a GetCsd() callback to handle > different implementations for different vendor. Do you mind that I append > the GetCsd() callback in EFI_SD_MMC_PASS_THRU_PROTOCOL to fix this issue? >
Unfortunately, you cannot simply add methods to protocols that are defined by the UEFI spec. If the passthru protocol is lacking in functionality, we should work with the UEFI forum to get it amended. _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
