| 1 | From 3eeeee7302a9b25de1eeabd901d3bb678d9983d9 Mon Sep 17 00:00:00 2001 |
| 2 | From: Lars-Peter Clausen <lars@metafoo.de> |
| 3 | Date: Sat, 26 Feb 2011 15:32:30 +0100 |
| 4 | Subject: [PATCH 4/4] NAND: Optimize reading the eec data for the JZ4740 (evil hack) |
| 5 | |
| 6 | We know that the ecc data is continuous, this allows us to only read the ecc |
| 7 | data instead of the whole oob section, which slightly improves performance. |
| 8 | |
| 9 | Note that this is an evil hack, which will break platforms where the ecc data is |
| 10 | non-continuous. |
| 11 | --- |
| 12 | drivers/mtd/nand/nand_base.c | 16 +++++----------- |
| 13 | 1 files changed, 5 insertions(+), 11 deletions(-) |
| 14 | |
| 15 | --- a/drivers/mtd/nand/nand_base.c |
| 16 | +++ b/drivers/mtd/nand/nand_base.c |
| 17 | @@ -1011,8 +1011,8 @@ static int nand_read_page_hwecc_oob_firs |
| 18 | /* Read the OOB area first */ |
| 19 | /* Read the OOB area first */ |
| 20 | if (mtd->writesize > 512) { |
| 21 | - chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page); |
| 22 | - chip->read_buf(mtd, chip->oob_poi, mtd->oobsize); |
| 23 | + chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize + eccpos[0], page); |
| 24 | + chip->read_buf(mtd, ecc_code, chip->ecc.total); |
| 25 | chip->cmdfunc(mtd, NAND_CMD_RNDOUT, 0, -1); |
| 26 | } else { |
| 27 | chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page); |
| 28 | @@ -1020,9 +1020,6 @@ static int nand_read_page_hwecc_oob_firs |
| 29 | chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page); |
| 30 | } |
| 31 | |
| 32 | - for (i = 0; i < chip->ecc.total; i++) |
| 33 | - ecc_code[i] = chip->oob_poi[eccpos[i]]; |
| 34 | - |
| 35 | for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) { |
| 36 | int stat; |
| 37 | |
| 38 | @@ -1077,8 +1074,8 @@ static int nand_read_subpage_hwecc_oob_f |
| 39 | |
| 40 | /* Read the OOB area first */ |
| 41 | if (mtd->writesize > 512) { |
| 42 | - chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page); |
| 43 | - chip->read_buf(mtd, chip->oob_poi, mtd->oobsize); |
| 44 | + chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize + eccpos[0], page); |
| 45 | + chip->read_buf(mtd, ecc_code, chip->ecc.total); |
| 46 | chip->cmdfunc(mtd, NAND_CMD_RNDOUT, data_col_addr, -1); |
| 47 | } else { |
| 48 | chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page); |
| 49 | @@ -1086,9 +1083,6 @@ static int nand_read_subpage_hwecc_oob_f |
| 50 | chip->cmdfunc(mtd, NAND_CMD_READ0, data_col_addr, page); |
| 51 | } |
| 52 | |
| 53 | - for (i = 0; i < chip->ecc.total; i++) |
| 54 | - ecc_code[i] = chip->oob_poi[eccpos[i]]; |
| 55 | - |
| 56 | p = bufpoi + data_col_addr; |
| 57 | |
| 58 | for (i = eccbytes * start_step; num_steps; num_steps--, i += eccbytes, p += eccsize) { |
| 59 | |
