Are mmc open/close subcommands needed?

U-Boot Hector Palacios 4 participants 5 messages Jan 2, 2014 – Jan 9, 2014

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Hector Palacios

author

2014-01-02 16:53 UTC #0 lore raw

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

Marek Vasut

2014-01-02 23:36 UTC #1 lore raw

Quoted 12 lines · Hector Palacios

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

Quoted 8 lines

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

Otavio Salvador

2014-01-03 17:35 UTC #2 lore raw

Quoted 18 lines · Marek Vasut

Quoted 17 lines · Hector Palacios
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).

Quoted 5 lines

Quoted 3 lines
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'.

Signature · 3 lines

Otavio Salvador                             O.S. Systems
http://www.ossystems.com.br        http://code.ossystems.com.br
Mobile: +55 (53) 9981-7854            Mobile: +1 (347) 903-9750

Hector Palacios

author

2014-01-07 07:47 UTC #3 lore raw

Dear Otavio,

Quoted 25 lines · Otavio Salvador

Quoted 18 lines · Marek Vasut
Quoted 17 lines · Hector Palacios
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).
Quoted 5 lines
Quoted 3 lines
Best regards,
--
Hector Palacios
+CC Panto

Quoted 8 lines

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

Jaehoon Chung

2014-01-09 08:45 UTC #4 lore raw

Quoted 34 lines · Hector Palacios

Dear Otavio,
Quoted 31 lines · Otavio Salvador
Quoted 18 lines · Marek Vasut
Quoted 17 lines · Hector Palacios
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).
Quoted 5 lines
Quoted 3 lines
Best regards,
Signature · 1 line
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.

Quoted 7 lines

Quoted 2 lines
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

Quoted 9 lines

Best regards,

Signature · 5 lines

Hector Palacios
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