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Commit aa6d01fa authored by Mike Dunn's avatar Mike Dunn Committed by David Woodhouse
Browse files

mtd: docg4: fix oob reads 



This patch does two closely related things:

(1) Currently the ecc.read_page() method does not fill the nand->oob_poi buffer
with the oob data, but instead reads oob into a local buffer.  Fix this by
filling the oob_poi buffer instead of a local buffer.  The 'oob_required'
argument is quietly ignored; the device must always read oob after the page
data, and it is presumed that there's no harm in filling oob_poi, even when not
explicitly requested.

(2) Always read oob from the device in ecc.read_oob(), instead of copying it
from a local buffer under some circumstances.

Signed-off-by: default avatarMike Dunn <mikedunn@newsguy.com>
Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 036a1ac1

drivers/mtd/nand/docg4.c

+6 −27
Original line number Diff line number Diff line
@@ -378,9 +378,9 @@ static int correct_data(struct mtd_info *mtd, uint8_t *buf, int page) 
		 * bit flips(s) are not reported in stats.

		 */



		if (doc->oob_buf[15]) {

		if (nand->oob_poi[15]) {

			int bit, numsetbits = 0;

			unsigned long written_flag = doc->oob_buf[15];

			unsigned long written_flag = nand->oob_poi[15];

			for_each_set_bit(bit, &written_flag, 8)

				numsetbits++;

			if (numsetbits > 4) { /* assume blank */
@@ -428,7 +428,7 @@ static int correct_data(struct mtd_info *mtd, uint8_t *buf, int page) 
		/* if error within oob area preceeding ecc bytes... */

		if (errpos[i] > DOCG4_PAGE_SIZE * 8)

			change_bit(errpos[i] - DOCG4_PAGE_SIZE * 8,

				   (unsigned long *)doc->oob_buf);

				   (unsigned long *)nand->oob_poi);



		else    /* error in page data */

			change_bit(errpos[i], (unsigned long *)buf);
@@ -748,18 +748,12 @@ static int read_page(struct mtd_info *mtd, struct nand_chip *nand, 


	docg4_read_buf(mtd, buf, DOCG4_PAGE_SIZE); /* read the page data */



	/*

	 * Diskonchips read oob immediately after a page read.  Mtd

	 * infrastructure issues a separate command for reading oob after the

	 * page is read.  So we save the oob bytes in a local buffer and just

	 * copy it if the next command reads oob from the same page.

	 */



	/* this device always reads oob after page data */

	/* first 14 oob bytes read from I/O reg */

	docg4_read_buf(mtd, doc->oob_buf, 14);

	docg4_read_buf(mtd, nand->oob_poi, 14);



	/* last 2 read from another reg */

	buf16 = (uint16_t *)(doc->oob_buf + 14);

	buf16 = (uint16_t *)(nand->oob_poi + 14);

	*buf16 = readw(docptr + DOCG4_MYSTERY_REG);



	write_nop(docptr);
@@ -807,21 +801,6 @@ static int docg4_read_oob(struct mtd_info *mtd, struct nand_chip *nand, 


	dev_dbg(doc->dev, "%s: page %x\n", __func__, page);



	/*

	 * Oob bytes are read as part of a normal page read.  If the previous

	 * nand command was a read of the page whose oob is now being read, just

	 * copy the oob bytes that we saved in a local buffer and avoid a

	 * separate oob read.

	 */

	if (doc->last_command.command == NAND_CMD_READ0 &&

	    doc->last_command.page == page) {

		memcpy(nand->oob_poi, doc->oob_buf, 16);

		return 0;

	}



	/*

	 * Separate read of oob data only.

	 */

	docg4_command(mtd, NAND_CMD_READ0, nand->ecc.size, page);



	writew(DOC_ECCCONF0_READ_MODE | DOCG4_OOB_SIZE, docptr + DOC_ECCCONF0);