[U-Boot] common/xyzmodem.c, ymodem, slow behavior receiving bytes

[Marek Vasut]

Dear Angelo Dureghello,

> Hi all,
> 
> seems that mcf5307, working at 90Mhz, is not fast enough when "-Os -g"
> compile options are set.
> 
> I changed for test config.mk from
> 
> DBGFLAGS= -g # -DDEBUG
> OPTFLAGS= -Os #-fomit-frame-pointer
> 
> into
> 
> DBGFLAGS= #-g # -DDEBUG
> OPTFLAGS= -O2 #-Os #-fomit-frame-pointer
> 
> common compiles now with -O2 and ymodem works fine again at 115200.
> 
> Also, i don't understand why "-g" is set by default.
> Is there a way to override/customize this options for this cpu ?
> Or i have to definitely step down to 57600 ?

You can set up the CFLAGS in config.mk for your CPU.

btw. read RFC1855 please.

> Best Regards,
> Angelo Dureghello
> 
> On Sat, Nov 10, 2012 at 02:40:07PM +0100, Angelo Dureghello wrote:
> > Dear all,
> > 
> > i am experiencing a strange behavior on the u-boot ymodem protocol.
> > I am running u-boot, (pulled from origin/head yesterday) on a mcf5307
> > based board. I am currently working to include this board/cpu as
> > supported into u-boot.
> > 
> > cpu runs at 90Mhz (bus clock at 45), baud rate 115200.
> > 
> > On an older u-boot (2011.09.00122), i was able to upload files through
> > ymodem at 115200 without any issue.
> > 
> > Once pulled yesterday head, and installed on the board, i am no more able
> > to upload files. U-boot times out when the first 128 bytes block is
> > sent, and sends SYN (C) again, so i started some debugging on
> > xyzmodem.c:
> > 
> > Protocol times-out here, from line 434
> > 
> >   ....
> >   xyz.len = (c == SOH) ? 128 : 1024;
> >   xyz.bufp = xyz.pkt;
> >   for (i = 0; i < xyz.len; i++)
> >   
> >     {
> >     
> >       res = CYGACC_COMM_IF_GETC_TIMEOUT (*xyz.__chan, &c);
> >       ZM_DEBUG (zm_save (c));
> >       if (res)
> > 	
> > 	{
> > 	
> > 	  xyz.pkt[i] = c;
> > 	
> > 	}
> > 	
> >       else
> > 	
> > 	{
> > 	
> > 	  ZM_DEBUG (zm_dump (__LINE__));
> > 
> > ---->>    return xyzModem_timeout;
> > 
> > 	}
> > 	
> >     }
> > 
> > Echoing received char back to PC, i see about 1 every 3 received chars
> > seems lost somewhere, so the first 128bytes block is never completely
> > received (time out).
> > 
> > I measured baudrate through oscilloscope,
> > from PC to u-boot board, i have 115600
> > from u-boot board to PC, i have 117180 (still inside 2% tolerance)
> > 
> > Also verified timer/delay functions works properly in new u-boot build.
> > As clients i used minicom and other, and have the same result.
> > 
> > So from a first look, seems the receive routine from line 434 is no more
> > fast enough to receive the whole block. I moved speed down to 57600,
> > upload works fine again.
> > 
> > What do you think about ?
> > 
> > Best Regards,
> > Angelo Dureghello
> 
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