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Commit fe82ccef authored by Boris Brezillon's avatar Boris Brezillon
Browse files

mtd: nand: sunxi: implement ->read_subpage() 



Being able to read subpages can greatly improve read performances if the
MTD user is only interested in a small section of a NAND page.
This is particularly true with large pages (>= 8k).

Signed-off-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
parent 1c1bdd6f

drivers/mtd/nand/sunxi_nand.c

+36 −0
Original line number Diff line number Diff line
@@ -973,6 +973,39 @@ static int sunxi_nfc_hw_ecc_read_page(struct mtd_info *mtd, 
	return max_bitflips;

}



static int sunxi_nfc_hw_ecc_read_subpage(struct mtd_info *mtd,

					 struct nand_chip *chip,

					 u32 data_offs, u32 readlen,

					 u8 *bufpoi, int page)

{

	struct nand_ecc_ctrl *ecc = &chip->ecc;

	int ret, i, cur_off = 0;

	unsigned int max_bitflips = 0;



	sunxi_nfc_hw_ecc_enable(mtd);



	chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);

	for (i = data_offs / ecc->size;

	     i < DIV_ROUND_UP(data_offs + readlen, ecc->size); i++) {

		int data_off = i * ecc->size;

		int oob_off = i * (ecc->bytes + 4);

		u8 *data = bufpoi + data_off;

		u8 *oob = chip->oob_poi + oob_off;



		ret = sunxi_nfc_hw_ecc_read_chunk(mtd, data, data_off,

						  oob,

						  oob_off + mtd->writesize,

						  &cur_off, &max_bitflips,

						  !i, page);

		if (ret < 0)

			return ret;

	}



	sunxi_nfc_hw_ecc_disable(mtd);



	return max_bitflips;

}



static int sunxi_nfc_hw_ecc_write_page(struct mtd_info *mtd,

				       struct nand_chip *chip,

				       const uint8_t *buf, int oob_required,
@@ -1389,6 +1422,7 @@ static int sunxi_nand_hw_ecc_ctrl_init(struct mtd_info *mtd, 
	ecc->write_page = sunxi_nfc_hw_ecc_write_page;

	ecc->read_oob_raw = nand_read_oob_std;

	ecc->write_oob_raw = nand_write_oob_std;

	ecc->read_subpage = sunxi_nfc_hw_ecc_read_subpage;

	layout = ecc->layout;

	nsectors = mtd->writesize / ecc->size;
@@ -1635,6 +1669,8 @@ static int sunxi_nand_chip_init(struct device *dev, struct sunxi_nfc *nfc, 
	if (nand->options & NAND_NEED_SCRAMBLING)

		nand->options |= NAND_NO_SUBPAGE_WRITE;



	nand->options |= NAND_SUBPAGE_READ;



	ret = sunxi_nand_chip_init_timings(chip, np);

	if (ret) {

		dev_err(dev, "could not configure chip timings: %d\n", ret);