Re: [RESEND v5 09/21] mtd: rawnand: Create a new enumeration to describe properly ECC types

[Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>]

On Wed, 27 May 2020 10:44:30 +0200
Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> wrote:

> On Wed, 27 May 2020 10:33:56 +0200
> Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:
> 
> > Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> wrote on Wed, 27 May
> > 2020 00:59:28 +0200:
> >   
> > > On Tue, 26 May 2020 21:56:21 +0200
> > > Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:
> > >     
> > > > Now that the misleading mix between ECC engine type and OOB placement
> > > > has been addressed, add a new enumeration to properly define ECC types
> > > > (also called provider or mode).
> > > > 
> > > > Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
> > > > Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
> > > > ---
> > > >  drivers/mtd/nand/raw/nand_base.c |  7 +++++++
> > > >  include/linux/mtd/rawnand.h      | 16 ++++++++++++++++
> > > >  2 files changed, 23 insertions(+)
> > > > 
> > > > diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> > > > index 515cd4681660..5c6ab5b93270 100644
> > > > --- a/drivers/mtd/nand/raw/nand_base.c
> > > > +++ b/drivers/mtd/nand/raw/nand_base.c
> > > > @@ -5018,6 +5018,13 @@ static const char * const nand_ecc_modes[] = {
> > > >  	[NAND_ECC_ON_DIE]	= "on-die",
> > > >  };
> > > >  
> > > > +static const char * const nand_ecc_engine_providers[] = {      
> > > 
> > > This table is not used here, are you sure it should be introduced now?
> > >     
> > > > +	[NAND_ECC_ENGINE_NONE] = "none",
> > > > +	[NAND_ECC_ENGINE_SOFT] = "soft",
> > > > +	[NAND_ECC_ENGINE_CONTROLLER] = "hw",      
> > > 
> > > 					^ "on-controller" ?    
> > 
> > This would break DT backward compatibility, I am afraid I cannot do
> > that.  
> 
> You can always keep a translation table for the old prop
> (nand-ecc-mode) and have a new one for the new prop
> (nand-ecc-engine-type). But maybe you're not introducing a new property
> in this series, in which case the translation table here is just fine.

BTW, this DT prop is more a way to select among several ECC engines when
you have a choice, so maybe it should be named
nand-use-ecc-engine-type/nand-select-ecc-engine-type instead of
nand-ecc-provider/nand-ecc-engine-type.

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