[U-Boot] Are mmc open/close subcommands needed?
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
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
Best regards, Marek Vasut
On Thu, Jan 2, 2014 at 9:36 PM, Marek Vasut marex@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'.
Dear Otavio,
On 01/03/2014 06:35 PM, Otavio Salvador wrote:
On Thu, Jan 2, 2014 at 9:36 PM, Marek Vasut marex@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
On 01/07/2014 04:47 PM, Hector Palacios wrote:
Dear Otavio,
On 01/03/2014 06:35 PM, Otavio Salvador wrote:
On Thu, Jan 2, 2014 at 9:36 PM, Marek Vasut marex@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.
Well, I think also your opinion. This code is the same behavior. I didn't find any difference...
Best Regard, Jaehoon Chung
Best regards,
Hector Palacios _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
participants (4)
-
Hector Palacios -
Jaehoon Chung -
Marek Vasut -
Otavio Salvador