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From 98d33db1c87e2447b9b203399d2f995e05ecdb52 Mon Sep 17 00:00:00 2001
From: Lars-Peter Clausen <lars@metafoo.de>
Date: Sat, 26 Feb 2011 15:30:07 +0100
Subject: [PATCH 2/7] NAND: Optimize NAND_ECC_HW_OOB_FIRST read
Avoid sending unnecessary READ commands to the chip.
---
drivers/mtd/nand/nand_base.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -1360,9 +1360,16 @@ static int nand_read_page_hwecc_oob_firs
unsigned int max_bitflips = 0;
/* Read the OOB area first */
- chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
- chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
- chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
+ /* Read the OOB area first */
+ if (mtd->writesize > 512) {
+ chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page);
+ chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
+ chip->cmdfunc(mtd, NAND_CMD_RNDOUT, 0, -1);
+ } else {
+ chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
+ chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
+ chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
+ }
for (i = 0; i < chip->ecc.total; i++)
ecc_code[i] = chip->oob_poi[eccpos[i]];
@@ -1575,7 +1582,9 @@ static int nand_do_read_ops(struct mtd_i
__func__, buf);
read_retry:
- chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
+ if (chip->ecc.mode != NAND_ECC_HW_OOB_FIRST) {
+ chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
+ }
/*
* Now read the page into the buffer. Absent an error,
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