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openwrt-xburst/target/linux/xburst/patches-2.6.32/902-NAND-Optimize-NAND_ECC_HW_OOB_FIRST-read.patch
Lars-Peter Clausen 5629baf0c4 [xburst] Improve mounttime.
This patchset optimizes nand read access and reduces the ubi attach time by ~2/3
Credits go to dvdk for having the idea.
2011-05-10 06:59:58 -08:00

42 lines
1.5 KiB
Diff

From 93ad1a19872dfa2f4b9aa7b8d20581bda3057622 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 2/4] NAND: Optimize NAND_ECC_HW_OOB_FIRST read
Avoid sending unnecessary READ commands to the chip.
---
drivers/mtd/nand/nand_base.c | 15 +++++++++++----
1 files changed, 11 insertions(+), 4 deletions(-)
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -1008,9 +1008,16 @@ static int nand_read_page_hwecc_oob_firs
uint8_t *ecc_calc = chip->buffers->ecccalc;
/* 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]];
@@ -1177,7 +1184,7 @@ static int nand_do_read_ops(struct mtd_i
if (realpage != chip->pagebuf || oob) {
bufpoi = aligned ? buf : chip->buffers->databuf;
- if (likely(sndcmd)) {
+ if (likely(sndcmd) && chip->ecc.mode != NAND_ECC_HW_OOB_FIRST) {
chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
sndcmd = 0;
}