Hi Wolfgang, On Wed, Apr 13, 2011 at 3:31 AM, Wolfgang Denk <w...@denx.de> wrote: > Dear Lei Wen, > > In message <AANLkTikH_5rXgFsWbNRnBQtB6WFjT=2k8pd8cbxak...@mail.gmail.com> you > wrote: >> >> Further refine this idea, don't need to call mmc_register multi-times. >> For the purpose is to switch partition when needed, we really do want to one >> real device. So I propose a new solution as: >> >> Assume there is two sd/mmc controller on the board, named as mmc0&mmc1. >> The mmc0 attach with a sd card, and mmc1 attach with a emmc that has >> partition >> supported. Then we would have mmc(2, 3, 4, 5, 6, 7, 8) faked device map to >> mmc0 >> , mmc(9, 10, 11, 12, 13, 14, 15) map to mmc1. >> >> Give the command as "mmc read 9 0x1000000 0 0x10", uboot would get the >> real device >> num by 9/7, while hardware part num is (9-1-7*real_dev_num) that is 1. >> So we need >> to make mmc1 send the switch part 1 command to the emmc, then perform the >> read >> operation. >> >> If we want to run "mmc read 5 0x10000 0x10 0x5", the sd attach on mmc0 has no >> hardware partition suppport, it would simply refuse to execute that command. >> Or if we want to be more gracefully handled, we could let the read 5 >> perform like the >> read 0 command. > > This is ugly and error prone. > > Why don't you follow the existing examples from other storage devices, > where we have a "dev" subcommand that allows to select one of the > existing devices as "active" device? Similarly, you could here select > an active device/partition pair.
dev subcommand to act as "sw_part" in my first patch? > > This makes the access commands easier, and the user has much less > problems to figure out which number he has to use to specify the - > wrong - partition. > How about this solution? Like if want to access the dev 0 and hardware partition 1, we could use the command as "mmc read 0:1 ***". If not pass the :[part] parameter to the dev number, like "mmc read 0 ***", that would means the partition is 0 by default. For this case, if that device has no capabilty of multi hardware partition, it would act like normal, or switch to the default 0 before any further action. Best regads, Lei _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
