Re: [PATCH v2 09/11] mtd: rawnand: Expose monolithic read/write_page_raw() helpers

From: Boris Brezillon <boris.brezillon@collabora.com>
To: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Michal Simek <monstr@monstr.eu>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Tudor Ambarus <Tudor.Ambarus@microchip.com>,
	Richard Weinberger <richard@nod.at>,
	linux-mtd@lists.infradead.org,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Naga Sureshkumar Relli <nagasure@xilinx.com>
Subject: Re: [PATCH v2 09/11] mtd: rawnand: Expose monolithic read/write_page_raw() helpers
Date: Wed, 29 Apr 2020 21:03:23 +0200	[thread overview]
Message-ID: <20200429210323.41eca2b5@collabora.com> (raw)
In-Reply-To: <20200429185252.1b81a3ea@xps13>

On Wed, 29 Apr 2020 18:52:52 +0200
Miquel Raynal <miquel.raynal@bootlin.com> wrote:

> Hi Boris,
> 
> Boris Brezillon <boris.brezillon@collabora.com> wrote on Wed, 29 Apr
> 2020 18:31:37 +0200:
> 
> > On Wed, 29 Apr 2020 18:26:31 +0200
> > Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> >   
> > > Hi Boris,
> > > 
> > > Boris Brezillon <boris.brezillon@collabora.com> wrote on Wed, 29 Apr
> > > 2020 18:15:09 +0200:
> > >     
> > > > On Wed, 29 Apr 2020 17:55:38 +0200
> > > > Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> > > >       
> > > > > The current nand_read/write_page_raw() helpers are already widely used
> > > > > but do not fit the purpose of "constrained" controllers which cannot,
> > > > > for instance, separate command/address cycles with data cycles.
> > > > > 
> > > > > Workaround this issue by proposing alternative helpers that cannot be
> > > > > used by controller drivers instead.
> > > > > 
> > > > > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > > > > ---
> > > > >  drivers/mtd/nand/raw/nand_base.c | 60 ++++++++++++++++++++++++++++++++
> > > > >  include/linux/mtd/rawnand.h      |  8 +++--
> > > > >  2 files changed, 66 insertions(+), 2 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> > > > > index 15a9189b2307..2e525cb5a4e4 100644
> > > > > --- a/drivers/mtd/nand/raw/nand_base.c
> > > > > +++ b/drivers/mtd/nand/raw/nand_base.c
> > > > > @@ -2629,6 +2629,39 @@ int nand_read_page_raw(struct nand_chip *chip, uint8_t *buf, int oob_required,
> > > > >  }
> > > > >  EXPORT_SYMBOL(nand_read_page_raw);
> > > > >  
> > > > > +/**
> > > > > + * nand_monolithic_read_page_raw - Read raw page data without ECC in one go        
> > > > 
> > > > Maybe
> > > > 
> > > > "Read the full page (data + OOB) with ECC engine disabled"
> > > > 
> > > > ?      
> > > 
> > > This is not accurate as we don't enforce OOB read.    
> > 
> > Right
> >   
> > > 
> > > Don't you find "in one go" explicit enough?    
> > 
> > Well, "raw" and "without ECC" is redundant, that's the part I wanted to
> > see addressed. And the 'in one go' refers to the data/OOB split, which
> > is not clear here.
> >   
> 
> 
> What about
> 
>     "Send a single request to the controller driver to read raw data"
> 
> the end of the sentence might also be
> 
>     "...to read a page plus eventually the OOB area"

I think we should stick to something shorter here, like "Do a monolithic
page read in raw mode" and have a detailed description (basically
defining what 'raw' and 'monolithic' mean in this context) after the
arguments.

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