On Tue, Jan 28, 2014 at 12:25:02PM -0500, Tom Rini wrote: > Hey guys, > > I've posted a patch to support the eMMC boot partitions found on the TI > DRA7xx EVM the other day, and I've been looking at what exactly happens > with the 'mmc open ...' and 'mmc close ...' commands the > CONFIG_SUPPORT_EMMC_BOOT enables. I've got a few questions about how > exactly the support works on the SMDK5250 and what your platform > requirements are, so we can re-work the code to be a bit more generic. > > Why do we have it as "open" and "close" ? Is this because it's a > version 4.2[1] style device? I'm working with 4.3-compatible (it's > actually 4.41, but same method just larger partitions) one and that can > be done with setting EXT_CSD[179] (BOOT_CONFIG / Boot configuration) _and_ > EXT_CSD[177] to a specific and different value than we've hard-coded > now. > > I would like to change things to be: > "mmc open <device>" - Note required for eMMC 4.2 boot method. > "mmc close <device>" - Same > "mmc bootpart <device> <partition>" - Used for eMMC 4.3 and later boot > sequence option 1/2 > "mmc bootbus <device> <value>" - Note used in all boot sequences > > This would make the SMDK5250 sequence be (based on how I think it works > today): > mmc dev ... > mmc open > mmc write ... > mmc bootpart ... > mmc bootbus ... > mmc close > > And the DRA7xx sequence be: > mmc dev ... > mmc write ... > mmc bootpart ... > mmc bootbus ...
Oh! And I forgot the current 'bootpart' which appears to be a resize operation would become 'bootpart-resize'. -- Tom
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