Re: [PATCH] mtd: rawnand: initialize ntargets with maxchips

From: Boris Brezillon <boris.brezillon@collabora.com>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Richard Weinberger <richard@nod.at>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	linux-mtd@lists.infradead.org, kernel@pengutronix.de,
	Boris Brezillon <bbrezillon@kernel.org>
Subject: Re: [PATCH] mtd: rawnand: initialize ntargets with maxchips
Date: Tue, 21 May 2019 10:29:21 +0200	[thread overview]
Message-ID: <20190521102921.65353085@collabora.com> (raw)
In-Reply-To: <20190521081721.541-1-s.hauer@pengutronix.de>

On Tue, 21 May 2019 10:17:21 +0200
Sascha Hauer <s.hauer@pengutronix.de> wrote:

> memorg->ntargets is initialized with '1'. It should be initialized with
> the maxchips argument from nand_scan() instead. Otherwise multi chip
> support errors out on the secondary chip selects when trying to call
> nand_reset() on them:
> 
> WARNING: CPU: 0 PID: 1 at drivers/mtd/nand/raw/internals.h:114
> nand_reset_op+0x194/0x1c4
> 
> With this memorg->ntargets is initialized with the maximum number of
> chip selects supported by the driver. After having detected the number
> of actually connected chips memory->ntargets is updated with that
> number.
> 
> Fixes: 2813e288414 ("mtd: rawnand: Get rid of chip->numchips")
> 

You an get rid of this blank line.

> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  drivers/mtd/nand/raw/nand_base.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> index 7db0f04cf52b..0c717f3fb906 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -4621,7 +4621,8 @@ nand_manufacturer_name(const struct nand_manufacturer *manufacturer)
>  /*
>   * Get the flash and manufacturer id and lookup if the type is supported.
>   */
> -static int nand_detect(struct nand_chip *chip, struct nand_flash_dev *type)
> +static int nand_detect(struct nand_chip *chip, unsigned int maxchips,
> +		       struct nand_flash_dev *type)
>  {
>  	const struct nand_manufacturer *manufacturer;
>  	struct mtd_info *mtd = nand_to_mtd(chip);
> @@ -4638,7 +4639,7 @@ static int nand_detect(struct nand_chip *chip, struct nand_flash_dev *type)
>  	memorg = nanddev_get_memorg(&chip->base);
>  	memorg->planes_per_lun = 1;
>  	memorg->luns_per_target = 1;
> -	memorg->ntargets = 1;
> +	memorg->ntargets = maxchips;

I'd rather move this initialization to nand_scan_ident() as I don't like
the idea of passing maxchips to nand_detect(), but if you want to
keep it like that, can we at least rename the argument num_cs.

>  
>  	/*
>  	 * Reset the chip, required by some chips (e.g. Micron MT29FxGxxxxx)
> @@ -5004,7 +5005,7 @@ static int nand_scan_ident(struct nand_chip *chip, unsigned int maxchips,
>  		return ret;
>  
>  	/* Read the flash type */
> -	ret = nand_detect(chip, table);
> +	ret = nand_detect(chip, maxchips, table);
>  	if (ret) {
>  		if (!(chip->options & NAND_SCAN_SILENT_NODEV))
>  			pr_warn("No NAND device found\n");

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