Hi Macpaul, On Mon, Nov 14, 2011 at 2:36 PM, Macpaul Lin <macp...@gmail.com> wrote: > Hi Lei Wen, > > 2011/11/14 Lei Wen <adrian.w...@gmail.com>: >> Hi Macpaul, >> >> I see... >> It seems some socs always treat cmd8 as failed...? >> I think it is reasonable to add a quirk configuration surround the judgement >> of cmd8 execution, so that even it is failed anyway, it could still go on >> with >> the following cmd sequence. If this quirk is not defined, and return behavior >> is still kept. >> >> What do you think for this? >> >> Thanks, >> Lei >> > > I've not check this with the SD phy specification. > The command process should be backward compatible between 3.0 and 1.0. > > Could you please provide this more detail with the specification? > For example, could you please provide what section in the specification > and how the state machine in MMC card should be operated. > Then we can check it more detail and see if the solution is reasonable.
The 74 clock requirement is mentioned in both sd[1] and mmc spec[2]. [1] page 91, section 6.4.1 power up, SD specification, part 1, Physical layer Simplificated Specification, version 2.0 [2] page 54, section 7.3.1 Card reset to pre-idle state, JESD84-A44 > > Moreover, if you could provide where the Linux code is related to the problem > and how dose Linux deal with this problem will be good, also. For linux, it would direcly clear the HIGH SPEED flag for following mmc_send_app_op_cond(). Linux v3.2-rc1: drivers/mmc/core/sd.c: line 712 > > As you said in patch, "some card strictly obey the 74 clocks rule", > could you provide the information of the card that you're using? The card we met trouble on is SanDisk 8GB class4 sd card. > > Add #ifdef to the code is a quick solution, but I think the we need to > figure out if there is other method > to help on 74 clock adoptable on more general case. > > -- > Best regards, > Macpaul Lin > Best regards, Lei _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
