Re: [PATCH 6/8] mtd: rawnand: onfi: Simplify the NAND operations during detection

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Boris,

Boris Brezillon <boris.brezillon@collabora.com> wrote on Wed, 22 Apr
2020 09:00:52 +0200:

> On Tue, 21 Apr 2020 18:46:35 +0200
> Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> 
> > There is no need for separate parameter page reads, the delay penalty
> > is negligible so let's do read the three copies in one go.  
> 
> 		    ^let's read
> 
> In theory that's correct, but I fear this was done because some
> controllers couldn't read 768 bytes in one go. Could we do that only if
> the controller implements exec_op() and exec_op(check_only) returns true?

Thanks for reviewing all the patches. You are right that it might break
drivers so I'll find a more appropriate way to do it (same for JEDEC).

> 
> > 
> > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > ---
> >  drivers/mtd/nand/raw/nand_onfi.c | 8 +-------
> >  1 file changed, 1 insertion(+), 7 deletions(-)
> > 
> > diff --git a/drivers/mtd/nand/raw/nand_onfi.c b/drivers/mtd/nand/raw/nand_onfi.c
> > index d6124180b47b..b76772666b82 100644
> > --- a/drivers/mtd/nand/raw/nand_onfi.c
> > +++ b/drivers/mtd/nand/raw/nand_onfi.c
> > @@ -160,19 +160,13 @@ int nand_onfi_detect(struct nand_chip *chip)
> >  	if (!pbuf)
> >  		return -ENOMEM;
> >  
> > -	ret = nand_read_param_page_op(chip, 0, NULL, 0);
> > +	ret = nand_read_param_page_op(chip, 0, pbuf, 3 * sizeof(*pbuf));
> >  	if (ret) {
> >  		ret = 0;
> >  		goto free_onfi_param_page;
> >  	}
> >  
> >  	for (i = 0; i < 3; i++) {
> > -		ret = nand_read_data_op(chip, &pbuf[i], sizeof(*pbuf), true);
> > -		if (ret) {
> > -			ret = 0;
> > -			goto free_onfi_param_page;
> > -		}
> > -
> >  		crc = onfi_crc16(ONFI_CRC_BASE, (u8 *)&pbuf[i], 254);
> >  		if (crc == le16_to_cpu(pbuf[i].crc)) {
> >  			p = &pbuf[i];  
> 

Thanks,
Miquèl

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