Re: [PATCH 2/2] mtd: rawnand: Add timings for Kioxia TH58NVG2S3HBAI4

[Miquel Raynal <miquel.raynal@xxxxxxxxxxx>]

Hi Boris,

Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> wrote on Wed, 20 May
2020 16:50:22 +0200:

> On Wed, 20 May 2020 14:42:31 +0000
> Rickard X Andersson <Rickard.Andersson@xxxxxxxx> wrote:
> 
> > > > If I understand you correctly you want me to use onfi_find_equivalent_sdr_mode in order to find the corresponding onfi mode. Then you want me to use onfi_fill_data_interface and loop towards mode 0 checking which mode the controller accepts? I just thought it was a "messy" to duplicate this code in all vendor drivers.
> > > > Or do you mean that I should just use onfi_find_equivalent_sdr_mode to set ."timings.mode" and let nand_base to do the looping in case error is returned from th58nvg2s3hbai4_choose_data_interface (i.e specialized timings not accepted by the controller).    
> > >
> > > Sorry for the misunderstanding. What I think you should try is:
> > > 1/ call onfi_find_equivalent_sdr_mode() to set the timings.mode field.
> > > 2/ call nand_controller_supports_data_interface()
> > > 3/ if the controller supports the timings, set
> > > chip->default_timing_mode accordingly and return 0.  
> 
> Why do we have to set the default_timing_mode field? Can't we just set
> timings.mode directly?
> 
> > > 4/ if the controller does not support the timings, you may want to
> > > propose other standard timings to test by setting
> > > chip->default_timing_mode anyway but returning an error which means
> > > "best interface has not been found yet" so the rest of the
> > > choose_data_interface() helper will try the remaining ONFI modes
> > > automatically (fallbacks to 0 anyway).  
> 
> Again, I don't see why setting chip->default_timing_mode is needed here,
> and I'm not sure trying remaining ONFI modes is useful, I guess we can
> just fall back on mode 0 in that case.

It is needed because of the logic in nand_reset() which does not apply
the data interface after a reset if this field is null.

Otherwise I also wondered if falling back to regular ONFI mode was
useful. If this is not, we can just return after the call to
chip->ops.choose_data_interface().

Thanks,
Miquèl

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/