[U-Boot] Saving environment variables in MMC
Hi!
I want to save and retrieve environment variables from a file in MMC. Can I get some pointers towards this?
Whether env_relocate_spec() and other such functions, has some implementation for MMC also?
regards -Nitin
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On Monday 29 March 2010 11:21:22 Nitin Mahajan wrote:
I want to save and retrieve environment variables from a file in MMC. Can I get some pointers towards this?
Whether env_relocate_spec() and other such functions, has some implementation for MMC also?
search the archives. some people have posted some patches recently. -mike
Hello,
--- On Mon, 29/3/10, Mike Frysinger vapier@gentoo.org wrote:
From: Mike Frysinger vapier@gentoo.org Subject: Re: [U-Boot] Saving environment variables in MMC To: u-boot@lists.denx.de, nitinm76@yahoo.com Date: Monday, 29 March, 2010, 11:12 PM On Monday 29 March 2010 11:21:22 Nitin Mahajan wrote:
I want to save and retrieve environment variables from
a file in MMC. Can I
get some pointers towards this?
Whether env_relocate_spec() and other such functions,
has some
implementation for MMC also?
search the archives. some people have posted some patches recently. -mike
I checked the mails and I would go through the patches. In addition to this, I need to modify the environment variables(stored in a file) from Linux userland.
Whether it is OK to follow such an approach?
For this whether tools\fw_env.c is the right option?
regards
-Nitin
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2010/3/30 Nitin Mahajan nitinm76@yahoo.com:
Hello,
--- On Mon, 29/3/10, Mike Frysinger vapier@gentoo.org wrote:
From: Mike Frysinger vapier@gentoo.org Subject: Re: [U-Boot] Saving environment variables in MMC To: u-boot@lists.denx.de, nitinm76@yahoo.com Date: Monday, 29 March, 2010, 11:12 PM On Monday 29 March 2010 11:21:22 Nitin Mahajan wrote:
I want to save and retrieve environment variables from
a file in MMC. Can I
get some pointers towards this?
Found this in the past: http://bitshrine.org/gpp/u-boot-200910-cd77dd10-save-the-env-var-to-SDcard-a... might be a useful starter.
Have fun! Frans
Frans Meulenbroeks wrote:
2010/3/30 Nitin Mahajan nitinm76@yahoo.com:
Hi,
Found this in the past: http://bitshrine.org/gpp/u-boot-200910-cd77dd10-save-the-env-var-to-SDcard-a...
You can take a look at this one, too:
http://lists.denx.de/pipermail/u-boot/2009-November/063775.html
The patch has open comments, but the developer stated he will send an updated version for review.
Regards, Stefano Babic
Hello, --- On Wed, 31/3/10, Stefano Babic sbabic@denx.de wrote:
From: Stefano Babic sbabic@denx.de Subject: Re: [U-Boot] Saving environment variables in MMC To: nitinm76@yahoo.com Cc: "Frans Meulenbroeks" fransmeulenbroeks@gmail.com, "U-Boot user list" u-boot@lists.denx.de Date: Wednesday, 31 March, 2010, 4:17 PM Frans Meulenbroeks wrote:
2010/3/30 Nitin Mahajan nitinm76@yahoo.com:
Hi,
Found this in the past: http://bitshrine.org/gpp/u-boot-200910-cd77dd10-save-the-env-var-to-SDcard-a...
You can take a look at this one, too:
http://lists.denx.de/pipermail/u-boot/2009-November/063775.html
Thanks for the information. I just wanted to have a feedback, whether having a use-case of writing env variables from Linux User space is a good idea or is not recommended?
regards
-Nitin
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Nitin Mahajan wrote:
Hello, --- On Wed, 31/3/10, Stefano Babic sbabic@denx.de wrote:
Thanks for the information. I just wanted to have a feedback, whether having a use-case of writing env variables from Linux User space is a good idea or is not recommended?
Yes, it is possible to share info between Linux and u-boot. Take a look at the tools/env directory to see how.
Regards, Stefano Babic
Hi Nitin,
Thanks for the information. I just wanted to have a feedback, whether having a use-case of writing env variables from Linux User space is a good idea or is not recommended?
You found tools/env/fw_env.c showing that this functionality is indeed foreseen and used.
It is rather common to write to the U-Boot environment in projects for example to switch to a new set of kernel+file system after an update from within linux for the next boot.
Is this feedback enough?
Cheers Detlev
Thanks Detlev,
--- On Wed, 31/3/10, Detlev Zundel dzu@denx.de wrote:
From: Detlev Zundel dzu@denx.de Subject: Re: [U-Boot] Saving environment variables in MMC To: nitinm76@yahoo.com Cc: "U-Boot user list" u-boot@lists.denx.de Date: Wednesday, 31 March, 2010, 8:04 PM Hi Nitin,
Thanks for the information. I just wanted to have a
feedback, whether
having a use-case of writing env variables from Linux
User space is a
good idea or is not recommended?
You found tools/env/fw_env.c showing that this functionality is indeed foreseen and used.
It is rather common to write to the U-Boot environment in projects for example to switch to a new set of kernel+file system after an update from within linux for the next boot.
My use case is exactly same, to switch to a new set of kernel+fs after an update for the next boot.
I also have another usecase of updating the env variable 'bootargs' if required in the field. So this use-case combined with fw_env, what is your feedback?
Could you give me some pointers on upgrading u-boot itself, but I don't have a spare partition for that. I would have to replace working copy itself?
I would wanted to have more info(in addition to what I have implemented) regarding the failsafe upgrade mechanisms for embedded-linux apps and kernel? Could you please point me to right forums regarding this. I understand that this is not specific to u-boot, but just give me some pointers.
regards -Nitin
Is this feedback enough?
Cheers Detlev
-- The structure of a system reflects the structure of the organization that built it. -- Richard E. Fairley -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu@denx.de
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Hi Nitin,
It is rather common to write to the U-Boot environment in projects for example to switch to a new set of kernel+file system after an update from within linux for the next boot.
My use case is exactly same, to switch to a new set of kernel+fs after an update for the next boot.
I also have another usecase of updating the env variable 'bootargs' if required in the field. So this use-case combined with fw_env, what is your feedback?
It is doable of course. Maybe if I did not mention it before, I advise using a redundant environment for such procedures so that even a powerloss during this upgrade will not brick the device.
Could you give me some pointers on upgrading u-boot itself, but I don't have a spare partition for that. I would have to replace working copy itself?
I would not recommend upgrading U-Boot in the field. As it is not possible to build in redundancy for U-Boot (on most systems I know), there is always the possibility to kill the device with such an update.
I would wanted to have more info(in addition to what I have implemented) regarding the failsafe upgrade mechanisms for embedded-linux apps and kernel? Could you please point me to right forums regarding this. I understand that this is not specific to u-boot, but just give me some pointers.
I'm sorry that I cannot point you to a ready to use recipe here, as this really depends on your strategy regarding upgrades, i.e. will you do the upgrade from within Linux? (judging by your questions, you will...) Do you have enough ressources to keep two self-contained "program images" (at least kernel+dtb+rootfs) so you can always update "the other half"? If not, you will probably want to build a non-upgradeable fallback system which is only capable to update "the other part".
As you see, solving your problem really requires you to define your problem more rigorously first.
In order to protoect against interrupts during the update, you may very well want to have a watchdog on your system and use the "bootcount" (grep the documentation for it) feature of U-Boot to detect failing boot attempts.
I hope this is enough to get you started.
Cheers Detlev
Hello, thanks for your valuable inputs. --- On Thu, 1/4/10, Detlev Zundel dzu@denx.de wrote:
From: Detlev Zundel dzu@denx.de Subject: Re: [U-Boot] Saving environment variables in MMC To: nitinm76@yahoo.com Cc: "U-Boot user list" u-boot@lists.denx.de Date: Thursday, 1 April, 2010, 5:35 PM Hi Nitin,
It is rather common to write to the U-Boot
environment in projects
for example to switch to a new set of kernel+file
system after an
update from within linux for the next boot.
My use case is exactly same, to switch to a new set of
kernel+fs after
an update for the next boot.
I also have another usecase of updating the env
variable 'bootargs' if
required in the field. So this use-case combined with
fw_env, what is
your feedback?
It is doable of course. Maybe if I did not mention it before, I advise using a redundant environment for such procedures so that even a powerloss during this upgrade will not brick the device.
I will grep the mailing list archives for more info on the redundant environment technique.
Could you give me some pointers on upgrading u-boot
itself, but I
don't have a spare partition for that. I would have to
replace working
copy itself?
I would not recommend upgrading U-Boot in the field. As it is not possible to build in redundancy for U-Boot (on most systems I know), there is always the possibility to kill the device with such an update.
I would wanted to have more info(in addition to what I
have
implemented) regarding the failsafe upgrade mechanisms
for
embedded-linux apps and kernel? Could you please point
me to right
forums regarding this. I understand that this is not
specific to
u-boot, but just give me some pointers.
I'm sorry that I cannot point you to a ready to use recipe here, as this really depends on your strategy regarding upgrades, i.e. will you do the upgrade from within Linux? (judging by your questions, you will...) Do you have enough ressources to keep two self-contained "program images" (at least kernel+dtb+rootfs) so you can always update "the other half"? If not, you will probably want to build a non-upgradeable fallback system which is only capable to update "the other part".
As you see, solving your problem really requires you to define your problem more rigorously first.
In order to protoect against interrupts during the update, you may very well want to have a watchdog on your system and use the "bootcount" (grep the documentation for it) feature of U-Boot to detect failing boot attempts.
Ya I did that, implemented the store bootcount and load bootcount routines for OMAP 35x.
regards
-Nitin
I hope this is enough to get you started.
Cheers Detlev
-- Thanks so much for Emacs. What a wondrous system -- one of the real seven wonders of the world. Forced to choose between Emacs and, say, any pyramid, I'd take Emacs. -- Robert Boyer -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu@denx.de
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Hello,
--- On Thu, 1/4/10, Detlev Zundel dzu@denx.de wrote:
From: Detlev Zundel dzu@denx.de Subject: Re: [U-Boot] Saving environment variables in MMC To: nitinm76@yahoo.com Cc: "U-Boot user list" u-boot@lists.denx.de Date: Thursday, 1 April, 2010, 5:35 PM Hi Nitin,
It is rather common to write to the U-Boot
environment in projects
for example to switch to a new set of kernel+file
system after an
update from within linux for the next boot.
My use case is exactly same, to switch to a new set of
kernel+fs after
an update for the next boot.
I also have another usecase of updating the env
variable 'bootargs' if
required in the field. So this use-case combined with
fw_env, what is
your feedback?
It is doable of course. Maybe if I did not mention it before, I advise using a redundant environment for such procedures so that even a powerloss during this upgrade will not brick the device.
Can I get some pointers to some example implementation of a redundant environment. I mean how does a switching between the environments happen? Who clears or sets the obsolete flag for the redundant env?
-Nitin
Could you give me some pointers on upgrading u-boot
itself, but I
don't have a spare partition for that. I would have to
replace working
copy itself?
I would not recommend upgrading U-Boot in the field. As it is not possible to build in redundancy for U-Boot (on most systems I know), there is always the possibility to kill the device with such an update.
I would wanted to have more info(in addition to what I
have
implemented) regarding the failsafe upgrade mechanisms
for
embedded-linux apps and kernel? Could you please point
me to right
forums regarding this. I understand that this is not
specific to
u-boot, but just give me some pointers.
I'm sorry that I cannot point you to a ready to use recipe here, as this really depends on your strategy regarding upgrades, i.e. will you do the upgrade from within Linux? (judging by your questions, you will...) Do you have enough ressources to keep two self-contained "program images" (at least kernel+dtb+rootfs) so you can always update "the other half"? If not, you will probably want to build a non-upgradeable fallback system which is only capable to update "the other part".
As you see, solving your problem really requires you to define your problem more rigorously first.
In order to protoect against interrupts during the update, you may very well want to have a watchdog on your system and use the "bootcount" (grep the documentation for it) feature of U-Boot to detect failing boot attempts.
I hope this is enough to get you started.
Cheers Detlev
-- Thanks so much for Emacs. What a wondrous system -- one of the real seven wonders of the world. Forced to choose between Emacs and, say, any pyramid, I'd take Emacs. -- Robert Boyer -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu@denx.de
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participants (5)
-
Detlev Zundel -
Frans Meulenbroeks -
Mike Frysinger -
Nitin Mahajan -
Stefano Babic