Which way to store log in flash on mpc8xx?

Wolfgang Denk wd at denx.de
Tue Sep 20 01:37:47 EST 2005

In message <200509191155.36540.david.jander at protonic.nl> you wrote:
> Kernel of choice seems to be denx linuxppc_2_4_devel, but I cannot trust the 
> version of jffs2 used in that kernel anymore. Somtimes gc.c crashes with a 
> BUG() in line 139, and sometimes processes are frozen for a looong time 

Can you provide a little more details? The MTD / JFFS2 code  in  this
kernel  is  not too old, andwe use it in a couple of projects without
such problems.

> waiting for GC. I have debugged that problem a little bit, and definitely, 
> the FLASH access works ok, and the chip is new. No CRC- or read-errors, but 
> still gc.c crashes.

Can you provide soem more information for debugging?

> The version of mtd/jffs2 drivers in that kernel seem to be from march/2005 cvs 
> code, but when I read the following, I get even more scared:
> http://www.linux-mtd.infradead.org/source.html#kernelversions

Don't worry. We backported the MTD / JFFS2 code. See the  history  of
changes on our CVS or git server.

> This must be a very common task (to store logfiles in flash), but I just can't 
> seem to find the right way to do it.

Note that log files may cause a lot of trouble  when  using  a  JFFS2
file  system. Youmay want to addd a buffering layer, like pramfs in a
dedicated RAM area (SRAM ideally).

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Never underestimate the bandwidth of a station wagon full of tapes.
                                -- Dr. Warren Jackson, Director, UTCS

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