[PATCH v2 1/2] commands: change Y-Modem implementation

Jean-Christophe PLAGNIOL-VILLARD plagnioj at jcrosoft.com
Mon Nov 5 14:49:07 EST 2012


On 19:49 Mon 05 Nov     , Robert Jarzmik wrote:
> Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com> writes:
> > On 19:07 Mon 05 Nov     , Robert Jarzmik wrote:
> >> Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com> writes:
> >> No timeout indeed, on purpose.
> >> 
> >> The short explanation is that in a purge situation, all incoming data must be
> >> flushed, regardless of the time it takes.
> >> 
> >> The long explantion is :
> >>  - suppose the while(cdev->tstc(cdev)) takes a lot of time
> >>  - this implies that :
> >>    => the sender is sending data as fast as the reader can consume (not quite
> >>    probable, but why not ...)
> >>    => the sender has gone crazy, as in *-Modem protocol when this function is
> >>    called, no more than 1029 bytes can be sent by a *sane* sender
> >> 
> >> So let's take as granted that the sender has gone crazy (or hardware is brain
> >> dead). What will happen if I place a timeout here ?
> >>  - first, I'll obviously get out of xy_flush()
> >>  - then, as I receive garbage, xy_handle() will exit with either -EBADMSG or
> >>  -EILSEQ. So far so good.
> >>  - then the loady command will finish on error. Still good.
> >>  - then the input console will take over, and execute all the garbage sent to
> >>  it.
> >>    This is definitely something we don't want. Imagine in the garbage you have
> >>    something like "erase /dev/mtd0" ... Therefore, no timeout.
> > my issue is how can I interrupt it from barebox
> You can't, how could you ? Your console is overwhelmed by garbage input, what
> could you possibly do to interrupt it apart from cutting down the sender ?
this is an issue if we have more than one we need be able to do so and I may
want to use it on an other console_device not necessarely the current one

I have often hw that have more than one uart
> 
> > can you put the v3 on a tree somewhere so I can pull it
> I'll try. I have no external git I can push to. If you have a hint ...
https://git.wiki.kernel.org/index.php/GitHosting

Best Regards,
J.
> 
> -- 
> Robert



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