Re: AW: [ECOS] cat zImage >/dev/mtd1 does not work

[Weiguang Shi <wgshizz at yahoo dot com>]

I was finally able to update the FIS directory which coexists with another 
partition on the same erase block.

- First, apply your patch to redboot.c
- Second, remove the code in mtdpart.c that marks partitions not 
  starting/ending on an erase block readonly
- Third, unlock (a utility in mtd-utils) the partition before 
  writing anything onto it.

Thanks and Cheers!
Wei

--- Gary Thomas <gary@mlbassoc.com> wrote:

> Weiguang Shi wrote:
> > I have to make it work, old or new ;-) So I've been trying to apply your patch
> > to 2.6.18 in a way that makes sense in uClinux-2.4.x.
> > 
> > The patch consists three parts and, besides the one I tried, there 
> > are (I patched and diff'ed them)
> > 
> >    87a88,91
> >    >                 if (buf[i].name[0] == 0xff) {
> >    >                         i = numslots;
> >    >                         break;
> >    >                 }
> > 
> > and
> >    127c131
> >    <                       continue;
> >    ---
> >    >                         break;
> >  
> > 
> > It appears to me that 0xff is significant in both parts. What does it mean?
> > I haven't been able to figure out how either will enable writing.
> > 
> > As my node starts up, I saw in the sequence 
> >         0x003e0000-0x003ff000 : "FIS directory"
> >         mtd: partition "FIS directory" doesn't end on an erase block -- force read-only
> >         0x003ff000-0x00400000 : "RedBoot config"
> >         mtd: partition "RedBoot config" doesn't start on an erase block boundary -- force
> > read-only
> > 
> > can I remove the code that forced read-only (in mtdpart.c) at start up as an alternative to
> > applying your patch?
> > 
> > Thanks!
> > Wei
> > 
> > 
> > In addition, I found this piece of code in redboot.c confusing.
> >    #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;
> >                 }
> > 
> > That is, if CONFIG_MTD_REDBOOT_PARTS_READONLY is defined, the partitions, "RedBoot",
> > "RedBoot config", and "FIS directory", are set writeable! Can you shed some light?
> 
> It looks like a bug; I'm not interested in pursuing it at the moment.
> 
> Replace the section bounded by
> 
> #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
> #endif
> 
> with
> 
> #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
> 
> Make sure you disable MTD_REDBOOT_PARTS_READONLY in your configuration.
> 
> > 
> > 
> >> image for the FIS partition back to /dev/mtd4
> >>> I still get 
> >>>       
> >>>     cat: Write Error: Read-only file system
> >> You missed the part of the patch that allows the FIS directory to be
> >> writable even if you have combined FIS & FCONFIG.  I don't have such an
> >> old system, so you'll need to figure out how to get that code in.
> >>
> >>> --- 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
> 
=== message truncated ===



 
____________________________________________________________________________________
Be a PS3 game guru.
Get your game face on with the latest PS3 news and previews at Yahoo! Games.
http://videogames.yahoo.com/platform?platform=120121

-- 
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss