[U-Boot] uboot redundancy.

[Joakim Tjernlund]

Sagar Heroorkar <sagar.heroorkar at gmail.com> wrote on 2010/07/21 19:09:50:
>
> Hi,
>
> Is there a other way that without building the 2 different linking address for
> the uboot to make the 2 uboots PIC in the same nor flash.

The only other way is to modify gcc so you don't need so many link_offs() calls.

 Jocke

> On Wed, Jul 21, 2010 at 12:27 PM, Joakim Tjernlund <joakim.tjernlund at transmode.se
> > wrote:
> Sagar Heroorkar <sagar.heroorkar at gmail.com> wrote on 2010/07/21 17:21:31:
> >
> > Hi All,
> >
> > Before i start using your ( Joakim )approach. I would like to get some tips
> > from Wolfgang or someone who can assist me here.
> >
> > I am working on nor flash which is 128 mb flash for the PPC4XX.
> >
> > My  goal is to make uboot redundant. having other copy of uboot if one fails to boot.
> > Architechure follows like this.
> >
> > Totally there will be 3 uboots. Golden uboot is the one which has basic logic
> > to pick which uboot from uboot 1 or uboot 2 (different copy).
> > uboot 1 and uboot 2 is flashed into some location of 16mb nor flash.

> Seems sane.
>
> >
> > Steps follows like this.
> >
> > 1)G-boot picks up uboot1/uboot2 based on environment variable. Basically we
> > jumps to that uboot and start booting it from there.

> Doesn't need to be an env var. I image one could mark each image (uboot 1 or
> uboot 2) with a flag instead. That way you don't need to parse the env.
>
> >
> > When i analysed the approach what Joakim implemented in http://www.mail-
> > archive.com/u-boot at lists.denx.de/msg26918.html.
> > He uses something like link_off() for each of the global data.
> >
> > * There will be too many link_offs() i have to use in uboot to make sure each
> > of the global data.

> There are a few link_offs() but not too many IMHO. Remember that my patches
> were complete for my board.
>
> > * As i will have 2 uboots which resides into seperate partitions. This requies
> > to build 2 uboots with different relotate_code logic/something .

> Yes, this is the other way, you need to build two images linked to different
> addresses and select the right one at install.
>
> >
> > I have read comments about this approach in the link what i pasted above.
> >
> > I would really appriciate if anyone replies (especially Wolfgang ) about
> > whether to go head with this approach before i spent much time on this.
> > Also if anyone has already done similar implentation for any of the boards
> let me know.
> >
> > -Sagar
> > On Mon, Jul 19, 2010 at 4:36 PM, Joakim Tjernlund <joakim.tjernlund at transmode.se
> > wrote:
> >
> >
> > Sagar Heroorkar <sagar.heroorkar at gmail.com> wrote on 2010/07/19 15:26:20:
> > >
> > > Hi Wlfgang,
> > >
> > > resending this.
> > >
> > > Please do reply
> > >
> > > -Sagar
> >
> > > On Fri, Jul 16, 2010 at 3:12 PM, Sagar Heroorkar <sagar.heroorkar at gmail.com> wrote:
> > > Hi Joakim,
> > >
> > > Graeme referred me to contact you for this.
> > >
> > > I am working on U-boot making it PIC for ppc 405ex based boards.
> > > I see in the following link http://www.mail-archive.com/u-boot@lists.denx.de/
> > > msg26918.html
> > > that you have implemented similar thing on 83xx board.
> > >
> > > I have downloaded latest u-boot from ftp server of denx. I dont see the
> > > functions what you have modified like LINKF_OFF() etc.
> > > I would like to know where is the source code for that. Also is there any
> > > document other than the mail thread that explains what you have chagned.
>
> > Hi Sagar
> >
> > The source isn't in u-boot. It is only available as the patches I sent at the time.
> > I don't have the patches handy as I am on vacation for 2 more weeks.
> >
> > >
> > > Thanks in advance.
> > >
> > > -Sagar
> > >