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Re: AW: cat zImage >/dev/mtd1 does not work
- From: Weiguang Shi <wgshizz at yahoo dot com>
- To: Gary Thomas <gary at mlbassoc dot com>
- Cc: ecos-discuss <ecos-discuss at ecos dot sourceware dot org>
- Date: Mon, 22 Jan 2007 18:08:10 -0800 (PST)
- Subject: Re: AW: [ECOS] cat zImage >/dev/mtd1 does not work
Thanks again.
My system is 2.4.x under snapgear-3.4.0 and I applied only the following part of the patch
since this only seems to be relevant.
#else
if (!memcmp(names, "FIS directory", 14)) {
// Special hack to let directory be read/write
if ((fl->img->size & (master->erasesize - 1)) != 0) {
parts[i].size = (fl->img->size + (master->erasesize - 1)) &
~(master->erasesize - 1);
}
}
When I tried to cat the modified ram image for the FIS partition back to /dev/mtd4
I still get
cat: Write Error: Read-only file system
Wei
--- Gary Thomas <gary@mlbassoc.com> wrote:
> Weiguang Shi wrote:
> > Gary,
> >
> > I'm at the point to flash the modified partition back but can't erase the
> > FIS partition /dev/mtd4
> >
> > # cat /proc/mtd
> > dev: size erasesize name
> > mtd0: 00080000 00020000 "RedBoot"
> > mtd1: 00100000 00020000 "kernel"
> > mtd2: 00200000 00020000 "ramdisk"
> > mtd3: 00020000 00020000 "kiyon_config"
> > mtd4: 0001f000 00020000 "FIS directory"
> > mtd5: 00001000 00020000 "RedBoot config"
> > # eraseall /dev/mtd4
> > eraseall: /dev/mtd4: Permission denied
> >
> > I realized that I may need to "unlock" it but both my attempts to do that
> > in RedBoot and Linux failed. In the former, "fis unlock" worked fine in
> > Redboot but after Linux boots up I still get the same "Permission denied"
> > error. In linux, my unlock resulted in
> > # unlock /dev/mtd4
> > Could not open mtd device: /dev/mtd4
> > # unlock /dev/mtd5
> > Could not open mtd device: /dev/mtd5
> >
> > Any ideas on how shall I proceed?
>
> The problem is that if you use combined FIS directory and FCONFIG data
> (which you are based on the map above), then the MTD layer makes both of
> those images read only. The attached patch can let you override this.
> It's based on the public 2.6.18 kernel.
>
> Note: you need to be careful doing these changes to your FLASH. If you
> simply erase the partition, RedBoot will lose everything. MTD is pretty
> cool and if you simply open /dev/mtd4 read/write, read the current contents,
> update them and then rewrite them, the MTD layer will take care of erasing
> and updating the appropriate portions.
>
> > --- Gary Thomas <gary@mlbassoc.com> wrote:
> >
> >> Weiguang Shi wrote:
> >>> That's even better and was the solution that I was looking for.
> >>> The question is how, from the OS, can I update the FIS. Obviously
> >>> I need to know the structure of the "FIS directory" partition and
> >>> find the offset of that checksum and insert a '0' there by
> >>> - reading the whole partition into ram,
> >>> - changing the bit, erasing the partition on the flash,
> >>> - and finally flashing the modified partition in the ram back.
> >>>
> >>> Any suggestions as to where to start?
> >> <redboot/fis.h>
> >>
> >> Also, drivers/mtd has some RedBoot FIS parsing code in it. You could
> >> look at it for pointers.
> >>
> >>> --- Gary Thomas <gary@mlbassoc.com> wrote:
> >>>
> >>>> Note: you don't really need to change RedBoot. Just update the
> >>>> FIS [directory] entry for the image you are changing, either with
> >>>> the corrected checksum, or the value 0. RedBoot ignores the checksum
> >>>> when the stored value is 0.
>
> --
> ------------------------------------------------------------
> Gary Thomas | Consulting for the
> MLB Associates | Embedded world
> ------------------------------------------------------------
> > diff -ubNr --exclude=.gitignore linux-2.6.18/drivers/mtd/redboot.c
> /tmp/fc_base/opt/amltd/develop/linuxppc-2.6/drivers/mtd/redboot.c
> --- linux-2.6.18/drivers/mtd/redboot.c 2006-09-19 21:42:06.000000000 -0600
> +++ /tmp/fc_base/opt/amltd/develop/linuxppc-2.6/drivers/mtd/redboot.c 2006-10-24
> 11:59:32.000000000 -0600
> @@ -85,6 +85,10 @@
>
> numslots = (master->erasesize / sizeof(struct fis_image_desc));
> for (i = 0; i < numslots; i++) {
> + if (buf[i].name[0] == 0xff) {
> + i = numslots;
> + break;
> + }
> if (!memcmp(buf[i].name, "FIS directory", 14)) {
> /* This is apparently the FIS directory entry for the
> * FIS directory itself. The FIS directory size is
> @@ -124,7 +128,7 @@
> struct fis_list *new_fl, **prev;
>
> if (buf[i].name[0] == 0xff)
> - continue;
> + break;
> if (!redboot_checksum(&buf[i]))
> break;
>
> @@ -196,14 +200,22 @@
> parts[i].size = fl->img->size;
> parts[i].offset = fl->img->flash_base;
> parts[i].name = names;
> -
> strcpy(names, fl->img->name);
> +
> #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
> if (!memcmp(names, "RedBoot", 8) ||
> !memcmp(names, "RedBoot config", 15) ||
> !memcmp(names, "FIS directory", 14)) {
> parts[i].mask_flags = MTD_WRITEABLE;
> }
> +#else
> + if (!memcmp(names, "FIS directory", 14)) {
> + // Special hack to let directory be read/write
> + if ((fl->img->size & (master->erasesize - 1)) != 0) {
> + parts[i].size = (fl->img->size + (master->erasesize - 1)) &
> ~(master->erasesize - 1);
> + }
> + }
> +
> #endif
> names += strlen(names)+1;
>
>
> > --
> Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
> and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
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