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mtd: rawnand: Clarify conditions to enable continuous reads

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The current logic is probably fine but is a bit convoluted. Plus, we
don't want partial pages to be part of the sequential operation just in
case the core would optimize the page read with a subpage read (which
would break the sequence). This may happen on the first and last page
only, so if the start offset or the end offset is not aligned with a
page boundary, better avoid them to prevent any risk.

Cc: stable@vger.kernel.org
Fixes: 003fe4b954 ("mtd: rawnand: Support for sequential cache reads")
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Tested-by: Martin Hundebøll <martin@geanix.com>
Link: https://lore.kernel.org/linux-mtd/20231215123208.516590-5-miquel.raynal@bootlin.com
This commit is contained in:
Miquel Raynal 2023-12-15 13:32:08 +01:00
parent a62c459795
commit 828f6df1bc
1 changed files with 17 additions and 9 deletions
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26
drivers/mtd/nand/raw/nand_base.c
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@ -3460,21 +3460,29 @@ static void rawnand_enable_cont_reads(struct nand_chip *chip, unsigned int page,
u32 readlen, int col)
{
struct mtd_info *mtd = nand_to_mtd(chip);
unsigned int end_page, end_col;
chip->cont_read.ongoing = false;
if (!chip->controller->supported_op.cont_read)
return;
if ((col && col + readlen < (3 * mtd->writesize)) ||
(!col && readlen < (2 * mtd->writesize))) {
chip->cont_read.ongoing = false;
return;
}
end_page = DIV_ROUND_UP(col + readlen, mtd->writesize);
end_col = (col + readlen) % mtd->writesize;
chip->cont_read.ongoing = true;
chip->cont_read.first_page = page;
if (col)
chip->cont_read.first_page++;
chip->cont_read.last_page = page + ((readlen >> chip->page_shift) & chip->pagemask);
page++;
if (end_col && end_page)
end_page--;
if (page + 1 > end_page)
return;
chip->cont_read.first_page = page;
chip->cont_read.last_page = end_page;
chip->cont_read.ongoing = true;
rawnand_cap_cont_reads(chip);
}