[U-Boot] accessing eMMC boot partitions from U-Boot

Tim Harvey tharvey at gateworks.com
Tue Mar 14 12:55:30 UTC 2017


On Mon, Mar 13, 2017 at 2:49 PM, Stephen Warren <swarren at wwwdotorg.org> wrote:
> On 03/13/2017 03:34 PM, Tim Harvey wrote:
>>
>> Greetings,
>>
>> I'm working with some boards with eMMC FLASH and understand that I can
>> set the fields of the PARTITION_CONFIG with the 'mmc partconf' command
>> to specify what partition is used for boot. Once I do that to set the
>> boot0 partition for example, how can I access that  partition from
>> within u-boot via mmc read/write? In Linux the kernel provides access
>> to user/boot0/boot1/rpmb via different devices, but I don't see u-boot
>> doing that.
>
>
> The "mmc dev" command can be used to select which MMC device to operate on.
> The "typical" command "mmc dev 0" selects the main partition on MMC device 0
> for later MMC-specific commands such as "mmc read". You can add an extra
> parameter to that command to request a specific HW partition, e.g. "mmc dev
> 0 1" selects boo0 of MMC device 0 and "mmc dev 0 2" selects boot1.
>
> A similar naming scheme exists for commands that take a complete device
> specification each time. For example, "part list mmc 0" to list partitions
> in the main partition on MMC device 0, or "part list mmc 0.1" to list
> partitions on boot0 of MMC device 0.

Stephen,

Thanks - I wasn't aware of this usage and this was exactly what I was
looking for.

Tim


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