Using nand_change_read_column_op() in nand_onfi_detect()

[Sascha Hauer]

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

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