Dear Otavio,
On 01/03/2014 06:35 PM, Otavio Salvador wrote:
On Thu, Jan 2, 2014 at 9:36 PM, Marek Vasut <ma...@denx.de> wrote:
On Thursday, January 02, 2014 at 05:53:00 PM, Hector Palacios wrote:
Hi,
I saw commit 2a91c9134675140853577b565210458b5774e6cf that introduces mmc
subcommands 'open' and 'close' to access eMMC boot partitions and was
wondering if they are really needed. Can't the same be achieved with
already existing 'mmc dev [dev] [part]' command?
mmc open <dev> <boot_partition>
is the same as
mmc dev <dev> <part>
where <part> is the boot partition
mmc close <dev> <boot_partition>
is the same as
mmc dev <dev> 0
as a 0 will switch to partition 0 (user data).
Best regards,
--
Hector Palacios
+CC Panto
No; this is for different use.
The open and close are to open the Boot partitions part of eMMC 4; by
default those eMMC will be using the user partitions, not the boot
area.
The nice, and confusing thing, is that those boot partitions also
start in address 0 as a 'virtual disk'.
I don't think they are different commands that do the same by coincidence. The 'mmc
dev' command, when passed a fourth argument for the partition is calling the function
'mmc_switch_part()'.
This function executes the CMD6 command to write the Extended CSD register
PARTITION_CONFIG field that gives you access to any MMC partition (user data area,
boot partitions 1 and 2, RPMB, General Purpose 1-4 partitions).
It doesn't look like specific eMMC commands are needed to access the boot partitions,
but maybe I'm misinterpreting the code.
Best regards,
--
Hector Palacios
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