Hi, Lukasz, >>>>>> For the current u-boot codes, only 4bit/1bit SD/SDHC bus width is >>>>> >>>>> support. >>>>> >>>>>> So for MMC card, we also support 4bit bus width, otherwiase, we >>>>>> will >>>>> >>>>>> get the 12bit bus width, which is not correct: >>>>> Andy ... can you please explain? I don't quite understand the >>>>> problem, I thought we had no problem supporting 8bit mmc (esp. if >>>>> the controller handles that for us mostly). >>>> >>>> Yes, the controller support 8bit MMC. >>>> >>>> FSL ESDHC driver set the host_caps = MMC_MODE_4BIT | MMC_MODE_8BIT; >>>> But, the current codes for MMC card has been changed to: >>>> >>>> } else { >>>> width = ((mmc->host_caps & MMC_MODE_MASK_WIDTH_BITS) >> >>>> MMC_MODE_WIDTH_BITS_SHIFT); > > Hmm... looks like it is code done by me :-) > So little explanation shall be given. > > This code is necessary for some targets (like Samsung's Goni) which can > only support 4 bit MMC mode. > >>>> for (; width >= 0; width--) { >>>> .... >>>> >>>> So for FSL ESDHC, the width = 3, after implement mmc_switch >>>> successfully, will set the bus to 4 * width. Therefore, I will get >>>> the 12bit (4 x 3) bus width. >> This problem is MMC subsystem's bug. >> I think good that will modify the code in mmc.c. >> If caps is set to MMC_MODE_4BIT | MMC_MODE_8BIT, >> we can see the 12bit support with using "mmcinfo" command >> > > The mmc_set_bus_width(mmc, 4 * width) in conjunction to above code > causes the problem. then how about using the width[idx] like kernel?
Best Regards, Jaehoon Chung > > I agree, that this code shall be refactored. > Lei, what do you think? > > >> Best Regards, >> Jaehoon Chung >> >>>> >>>> Below is the old codes (width = 2): >>>> } else { >>>> for (width = EXT_CSD_BUS_WIDTH_8; width >= 0; >>>> width--) { >>> [...] >>> >>> >>> Uh, so it's a bug in the MMC subsystem? >>> Best regards, >>> Marek Vasut >>> _______________________________________________ >>> U-Boot mailing list >>> U-Boot@lists.denx.de >>> http://lists.denx.de/mailman/listinfo/u-boot >>> >> >> _______________________________________________ >> U-Boot mailing list >> U-Boot@lists.denx.de >> http://lists.denx.de/mailman/listinfo/u-boot > > > _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot