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5629baf0c4
This patchset optimizes nand read access and reduces the ubi attach time by ~2/3 Credits go to dvdk for having the idea.
59 lines
2.2 KiB
Diff
59 lines
2.2 KiB
Diff
From 3eeeee7302a9b25de1eeabd901d3bb678d9983d9 Mon Sep 17 00:00:00 2001
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From: Lars-Peter Clausen <lars@metafoo.de>
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Date: Sat, 26 Feb 2011 15:32:30 +0100
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Subject: [PATCH 4/4] NAND: Optimize reading the eec data for the JZ4740 (evil hack)
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We know that the ecc data is continuous, this allows us to only read the ecc
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data instead of the whole oob section, which slightly improves performance.
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Note that this is an evil hack, which will break platforms where the ecc data is
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non-continuous.
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---
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drivers/mtd/nand/nand_base.c | 16 +++++-----------
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1 files changed, 5 insertions(+), 11 deletions(-)
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--- a/drivers/mtd/nand/nand_base.c
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+++ b/drivers/mtd/nand/nand_base.c
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@@ -1011,8 +1011,8 @@ static int nand_read_page_hwecc_oob_firs
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/* Read the OOB area first */
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/* Read the OOB area first */
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if (mtd->writesize > 512) {
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- chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page);
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- chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
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+ chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize + eccpos[0], page);
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+ chip->read_buf(mtd, ecc_code, chip->ecc.total);
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chip->cmdfunc(mtd, NAND_CMD_RNDOUT, 0, -1);
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} else {
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chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
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@@ -1020,9 +1020,6 @@ static int nand_read_page_hwecc_oob_firs
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chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
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}
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- for (i = 0; i < chip->ecc.total; i++)
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- ecc_code[i] = chip->oob_poi[eccpos[i]];
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-
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for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
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int stat;
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@@ -1077,8 +1074,8 @@ static int nand_read_subpage_hwecc_oob_f
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/* Read the OOB area first */
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if (mtd->writesize > 512) {
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- chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page);
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- chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
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+ chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize + eccpos[0], page);
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+ chip->read_buf(mtd, ecc_code, chip->ecc.total);
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chip->cmdfunc(mtd, NAND_CMD_RNDOUT, data_col_addr, -1);
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} else {
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chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
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@@ -1086,9 +1083,6 @@ static int nand_read_subpage_hwecc_oob_f
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chip->cmdfunc(mtd, NAND_CMD_READ0, data_col_addr, page);
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}
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- for (i = 0; i < chip->ecc.total; i++)
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- ecc_code[i] = chip->oob_poi[eccpos[i]];
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-
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p = bufpoi + data_col_addr;
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for (i = eccbytes * start_step; num_steps; num_steps--, i += eccbytes, p += eccsize) {
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