Re: Using nand_change_read_column_op() in nand_onfi_detect()

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: linux-mtd@lists.infradead.org
Subject: Re: Using nand_change_read_column_op() in nand_onfi_detect()
Date: Tue, 14 May 2024 13:53:16 +0200	[thread overview]
Message-ID: <20240514135316.4940a7b6@xps-13> (raw)
In-Reply-To: <ZkNPkzKmwMWzbyWJ@pengutronix.de>

Hi Sascha,

s.hauer@pengutronix.de wrote on Tue, 14 May 2024 13:48:35 +0200:

> Hi all,
> 
> I am currently stumbling over this in nand_onfi_detect():
> 
> 	for (i = 0; i < ONFI_PARAM_PAGES; i++) {
> 		if (!i)
> 			ret = nand_read_param_page_op(chip, 0, &pbuf[i],
> 						      sizeof(*pbuf));
> 		else if (use_datain)
> 			ret = nand_read_data_op(chip, &pbuf[i], sizeof(*pbuf),
> 						true, false);
> 		else
> 			ret = nand_change_read_column_op(chip, sizeof(*pbuf) * i,
> 							 &pbuf[i], sizeof(*pbuf),
> 							 true);
> 		...
> 	}
> 
> nand_change_read_column_op() heavily uses mtd->writesize and bails out
> with an error when the writesize is 0. mtd->writesize is still
> uninitialised at that point, it's initialized a few lines further down
> in the same function. It looks like this code never worked as expected.
> 
> Also it seems use_datain is always 0, see 1), so existing code only ever
> reads the first parameter page.
> 
> The same pattern is in nand_jedec_detect() as well.
> 
> Not sure what we make from this.
> 
> Sascha
> 
> 1) https://lore.kernel.org/linux-mtd/20240514103355.817056-1-s.hauer@pengutronix.de/T/#u
> 

Sorry for not mentioning that before, I sent two fixes about that:
https://lore.kernel.org/linux-mtd/20240507160546.130255-1-miquel.raynal@bootlin.com/T/#t

Thanks,
Miquèl

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