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Commit 35d5d20e authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Brian Norris
Browse files

mtd: mxc_nand: cleanup copy_spare function 



To give people without the reference manual at hand a chance to
understand how spare area is handled in the i.MX nand controller,
improve commenting, naming of variables and coding style.

No functional change intended.

Reviewed-by: default avatarSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
[baruch: declare oob_chunk_size; update comments; reword commit log]
Signed-off-by: default avatarBaruch Siach <baruch@tkos.co.il>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
parent bcb83a19

drivers/mtd/nand/mxc_nand.c

+31 −15
Original line number Diff line number Diff line
@@ -807,32 +807,48 @@ static void mxc_nand_select_chip_v2(struct mtd_info *mtd, int chip) 
}



/*

 * Function to transfer data to/from spare area.

 * The controller splits a page into data chunks of 512 bytes + partial oob.

 * There are writesize / 512 such chunks, the size of the partial oob parts is

 * oobsize / #chunks rounded down to a multiple of 2. The last oob chunk then

 * contains additionally the byte lost by rounding (if any).

 * This function handles the needed shuffling between host->data_buf (which

 * holds a page in natural order, i.e. writesize bytes data + oobsize bytes

 * spare) and the NFC buffer.

 */

static void copy_spare(struct mtd_info *mtd, bool bfrom)

{

	struct nand_chip *this = mtd->priv;

	struct mxc_nand_host *host = this->priv;

	u16 i, j;

	u16 n = mtd->writesize >> 9;

	u16 i, oob_chunk_size;

	u16 num_chunks = mtd->writesize / 512;



	u8 *d = host->data_buf + mtd->writesize;

	u8 __iomem *s = host->spare0;

	u16 t = host->devtype_data->spare_len;

	u16 sparebuf_size = host->devtype_data->spare_len;



	j = (mtd->oobsize / n >> 1) << 1;

	/* size of oob chunk for all but possibly the last one */

	oob_chunk_size = (mtd->oobsize / num_chunks) & ~1;



	if (bfrom) {

		for (i = 0; i < n - 1; i++)

			memcpy32_fromio(d + i * j, s + i * t, j);



		/* the last section */

		memcpy32_fromio(d + i * j, s + i * t, mtd->oobsize - i * j);

		for (i = 0; i < num_chunks - 1; i++)

			memcpy32_fromio(d + i * oob_chunk_size,

					s + i * sparebuf_size,

					oob_chunk_size);



		/* the last chunk */

		memcpy32_fromio(d + i * oob_chunk_size,

				s + i * sparebuf_size,

				mtd->oobsize - i * oob_chunk_size);

	} else {

		for (i = 0; i < n - 1; i++)

			memcpy32_toio(&s[i * t], &d[i * j], j);



		/* the last section */

		memcpy32_toio(&s[i * t], &d[i * j], mtd->oobsize - i * j);

		for (i = 0; i < num_chunks - 1; i++)

			memcpy32_toio(&s[i * sparebuf_size],

				      &d[i * oob_chunk_size],

				      oob_chunk_size);



		/* the last chunk */

		memcpy32_toio(&s[oob_chunk_size * sparebuf_size],

			      &d[i * oob_chunk_size],

			      mtd->oobsize - i * oob_chunk_size);

	}

}