Re: cfi_cmdset_0001.c: do_write_buffer: wrong length

["D. Vrabel" <dv207@cam.ac.uk>]

Hi,

Nicolas Pitre wrote:
> 
> On Fri, 8 Dec 2000, David Vrabel wrote:
> >
> > In cfi_cmdset_0001.c do_write_buffer writes an incorrect length to the
> > chip
> >
> >     cfi_write(map, CMD((len/(cfi->device_type*CFIDEV_INTERLEAVE))-1),
> >         cmd_adr);
> >
> > Should it it be?
> >     cfi_write(map, CMD(len/map->buswidth-1), cmd_adr);
> 
> No.  This will break the case where the interleave isn't 1.
> 
> Hmmm... Will it?
> 
> Euh...  Each time I get around this question I get confused...
> 
> Does someone have the data sheet nearby? (I don't ATM)...  What should the
> lenght be if a x16 chip is used in x8 mode?  bytes/sizeof(char) or
> bytes/sizeof(short)?
> 
> On a 2 x16 arrangement you have buswidth=4, interleave=2, devicetype=2.  In
> that case it should be len/4 - 1.
> 
> Maybe you are right after all.

Time to compile a big list of all the arrangements of chips and the
resultant buffer write length...

So far we have:

device type  interleave  bus width    buf write len
2 (x16)      1           1 (x8)       len/1-1
2 (x16)      1           2 (x16)      len/2-1
2 (x16)      2           4 (x32)      len/4-1

So far it len/buswidth-1...

David Vrabel


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