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Commit 7dcdcbef authored by David Woodhouse's avatar David Woodhouse
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[MTD] NAND: Combined oob buffer so it's contiguous with data 



Ditch the separate oobrbuf and oobwbuf fields from the chip buffers,
and use only a single buffer immediately after the data. This accommodates
NAND controllers such as the OLPC CAFÉ chip, which can't do scatter/gather
DMA so needs the OOB buffer to be contiguous with the data, for both read
and write.

Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent 513b046c

drivers/mtd/nand/nand_base.c

+5 −10
Original line number Diff line number Diff line
@@ -971,7 +971,6 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from, 
	page = realpage & chip->pagemask;



	col = (int)(from & (mtd->writesize - 1));

	chip->oob_poi = chip->buffers->oobrbuf;



	buf = ops->datbuf;

	oob = ops->oobbuf;
@@ -1270,8 +1269,6 @@ static int nand_do_read_oob(struct mtd_info *mtd, loff_t from, 
	realpage = (int)(from >> chip->page_shift);

	page = realpage & chip->pagemask;



	chip->oob_poi = chip->buffers->oobrbuf;



	while(1) {

		sndcmd = chip->ecc.read_oob(mtd, chip, page, sndcmd);

		buf = nand_transfer_oob(chip, buf, ops);
@@ -1625,7 +1622,9 @@ static int nand_do_write_ops(struct mtd_info *mtd, loff_t to, 
	    (chip->pagebuf << chip->page_shift) < (to + ops->len))

		chip->pagebuf = -1;



	chip->oob_poi = chip->buffers->oobwbuf;

	/* If we're not given explicit OOB data, let it be 0xFF */

	if (likely(!oob))

		memset(chip->oob_poi, 0xff, mtd->oobsize);



	while(1) {

		int cached = writelen > bytes && page != blockmask;
@@ -1654,9 +1653,6 @@ static int nand_do_write_ops(struct mtd_info *mtd, loff_t to, 
		}

	}



	if (unlikely(oob))

		memset(chip->oob_poi, 0xff, mtd->oobsize);



	ops->retlen = ops->len - writelen;

	return ret;

}
@@ -1744,7 +1740,6 @@ static int nand_do_write_oob(struct mtd_info *mtd, loff_t to, 
	if (page == chip->pagebuf)

		chip->pagebuf = -1;



	chip->oob_poi = chip->buffers->oobwbuf;

	memset(chip->oob_poi, 0xff, mtd->oobsize);

	nand_fill_oob(chip, ops->oobbuf, ops);

	status = chip->ecc.write_oob(mtd, chip, page & chip->pagemask);
@@ -2348,8 +2343,8 @@ int nand_scan_tail(struct mtd_info *mtd) 
	if (!chip->buffers)

		return -ENOMEM;



	/* Preset the internal oob write buffer */

	memset(chip->buffers->oobwbuf, 0xff, mtd->oobsize);

	/* Set the internal oob buffer location, just after the page data */

	chip->oob_poi = chip->buffers + mtd->writesize;



	/*

	 * If no default placement scheme is given, select an appropriate one

include/linux/mtd/nand.h

+1 −5
Original line number Diff line number Diff line
@@ -286,9 +286,7 @@ struct nand_ecc_ctrl { 
 * struct nand_buffers - buffer structure for read/write

 * @ecccalc:	buffer for calculated ecc

 * @ecccode:	buffer for ecc read from flash

 * @oobwbuf:	buffer for write oob data

 * @databuf:	buffer for data - dynamically sized

 * @oobrbuf:	buffer to read oob data

 *

 * Do not change the order of buffers. databuf and oobrbuf must be in

 * consecutive order.
@@ -296,9 +294,7 @@ struct nand_ecc_ctrl { 
struct nand_buffers {

	uint8_t	ecccalc[NAND_MAX_OOBSIZE];

	uint8_t	ecccode[NAND_MAX_OOBSIZE];

	uint8_t	oobwbuf[NAND_MAX_OOBSIZE];

	uint8_t databuf[NAND_MAX_PAGESIZE];

	uint8_t	oobrbuf[NAND_MAX_OOBSIZE];

	uint8_t databuf[NAND_MAX_PAGESIZE + NAND_MAX_OOBSIZE];

};



/**