Subject: Re: [PATCH v2 14/15] mtd: rawnand: Get rid of chip->numchips

From: Boris Brezillon <[email-masked]>
Date: Tue, 21 May 2019 09:33:02 +0200

On Tue, 21 May 2019 08:59:48 +0200
Sascha Hauer <[email-masked]> wrote:

> Hi,
> 
> On Mon, Mar 04, 2019 at 09:15:21PM +0100, Miquel Raynal wrote:
> > diff --git a/drivers/mtd/nand/raw/internals.h b/drivers/mtd/nand/raw/internals.h
> > index fbf6ca015cd7..a204f9d7e123 100644
> > --- a/drivers/mtd/nand/raw/internals.h
> > +++ b/drivers/mtd/nand/raw/internals.h
> > @@ -110,7 +110,7 @@ static inline int nand_exec_op(struct nand_chip *chip,
> >  	if (!nand_has_exec_op(chip))
> >  		return -ENOTSUPP;
> >  
> > -	if (WARN_ON(op->cs >= chip->numchips))
> > +	if (WARN_ON(op->cs >= nanddev_ntargets(&chip->base)))
> >  		return -EINVAL;  
> 
> This warning triggers when I apply my gpmi nand exec_op series.
> 
> The gpmi driver calls:
> 
> 	ret = nand_scan(chip, GPMI_IS_MX6(this) ? 2 : 1);
> 
> This ends up in nand_scan_ident() with maxchips = 2. Here nand_detect()
> is called which sets memorg->ntargets = 1; Later in nand_scan_ident() we
> have:
> 
> 	for (i = 1; i < maxchips; i++) {

This loop should be fixed to test against nanddev_ntargets() instead of
maxchips.

> 		u8 id[2];
> 
> 		/* See comment in nand_get_flash_type for reset */
> 		ret = nand_reset(chip, i);
> 		if (ret)
> 			break;
> 		....
> 
> this nand_reset() calls nand_exec_op() with op->cs = 1, nanddev_ntargets() = 1
> and boom.
> 
> I can't see how this can work with anything else but maxchips = 1. Do you
> have an idea how this is supposed to work?
> 
> Sascha
> 
> 

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