[U-Boot] [PATCH] cmd_sf: add handler for +len arg for all commands

[Marek Vasut]

On Sunday, October 05, 2014 at 09:51:27 PM, Maxime Hadjinlian wrote:
> On Sun, Oct 5, 2014 at 9:45 PM, Marek Vasut <marex at denx.de> wrote:
> > On Sunday, October 05, 2014 at 09:27:00 PM, Maxime Hadjinlian wrote:
> >> On Sun, Oct 5, 2014 at 9:19 PM,  <thomas.langer at lantiq.com> wrote:
> >> >> On Sunday, October 05, 2014 at 08:40:26 PM, Maxime Hadjinlian wrote:
> >> >> > Hi Thomas, all,
> >> >> > 
> >> >> > On Sun, Oct 5, 2014 at 7:43 PM,  <thomas.langer at lantiq.com> wrote:
> >> >> > > Hello Maxime,
> >> >> > > 
> >> >> > > can you explain the usecase?
> >> >> > > I think, only the erase is executed per sector, all other
> >> >> > > commands are working fine with a byte oriented length.
> >> >> > 
> >> >> > I need to write a file that is downloaded through TFTP. So I can
> >> >> > get the filesize through the variable of the same name, but if
> >> >> > it's not rounded, the write command may fail.
> >> >> > I can save the filesize in another variable, but at next boot, when
> >> >> > I need to read this file, I can't read the file, since I only know
> >> >> > it's size in byte, I need to be able to round it again.
> >> >> 
> >> >> I wonder, do all SPI flashes need to do sector-aligned writes ?
> >> > 
> >> > All the serial flashes I have seen so far do support reading and
> >> > writing with any length, independent from the erase size.
> >> > Otherwise the current implementation of env_sf.c would also not work.
> >> 
> >> Well the QSPI, I used, does not. Every read and write has to be
> >> aligned. That's why I needed that in the first place.
> > 
> > Aligned how exactly?
> 
> sector-aligned.
> If I write anything that is not sector aligned, the 'sf' command will fail.

Is that really a property of the SPI flash or the SPI controller ? And if the 
later, is it a property of a particular one or is that a common thing ?

Which SPI flash are you talking about and which controller ?

Best regards,
Marek Vasut