Re: [PATCH 04/10] Add yaffs2 file system: Flash interfacing and ECChandling code

From: Ryan Mallon
Date: Wed Jan 19 2011 - 18:27:39 EST

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cOn 01/14/2011 04:06 PM, Charles Manning wrote:
> Signed-off-by: Charles Manning <cdhmanning@xxxxxxxxx>

Hi Charles,

Is it possible to make features like yaffs doing its own ecc, ecc wrong
order and 9 byte tags mount options? It would reduce the number of
Kconfig options and the amount of ifdefery in these files.

More comments below.

~Ryan

> ---
> fs/yaffs2/yaffs_ecc.c | 296 +++++++++++++++++++++++++++++++++++++++++
> fs/yaffs2/yaffs_ecc.h | 44 ++++++
> fs/yaffs2/yaffs_mtdif.c | 53 ++++++++
> fs/yaffs2/yaffs_mtdif.h | 23 ++++
> fs/yaffs2/yaffs_mtdif1.c | 329 ++++++++++++++++++++++++++++++++++++++++++++++
> fs/yaffs2/yaffs_mtdif1.h | 29 ++++
> fs/yaffs2/yaffs_mtdif2.c | 215 ++++++++++++++++++++++++++++++
> fs/yaffs2/yaffs_mtdif2.h | 29 ++++
> fs/yaffs2/yaffs_nand.c | 120 +++++++++++++++++
> fs/yaffs2/yaffs_nand.h | 38 ++++++
> 10 files changed, 1176 insertions(+), 0 deletions(-)
> create mode 100644 fs/yaffs2/yaffs_ecc.c
> create mode 100644 fs/yaffs2/yaffs_ecc.h
> create mode 100644 fs/yaffs2/yaffs_mtdif.c
> create mode 100644 fs/yaffs2/yaffs_mtdif.h
> create mode 100644 fs/yaffs2/yaffs_mtdif1.c
> create mode 100644 fs/yaffs2/yaffs_mtdif1.h
> create mode 100644 fs/yaffs2/yaffs_mtdif2.c
> create mode 100644 fs/yaffs2/yaffs_mtdif2.h
> create mode 100644 fs/yaffs2/yaffs_nand.c
> create mode 100644 fs/yaffs2/yaffs_nand.h
>
> diff --git a/fs/yaffs2/yaffs_ecc.c b/fs/yaffs2/yaffs_ecc.c
> new file mode 100644
> index 0000000..4f29b80
> --- /dev/null
> +++ b/fs/yaffs2/yaffs_ecc.c
> @@ -0,0 +1,296 @@
> +/*
> + * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
> + *
> + * Copyright (C) 2002-2010 Aleph One Ltd.
> + * for Toby Churchill Ltd and Brightstar Engineering
> + *
> + * Created by Charles Manning <charles@xxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +/*
> + * This code implements the ECC algorithm used in SmartMedia.
> + *
> + * The ECC comprises 22 bits of parity information and is stuffed into 3 bytes.
> + * The two unused bit are set to 1.
> + * The ECC can correct single bit errors in a 256-byte page of data. Thus, two
> + * such ECC blocks are used on a 512-byte NAND page.
> + *
> + */
> +
> +/* Table generated by gen-ecc.c
> + * Using a table means we do not have to calculate p1..p4 and p1'..p4'
> + * for each byte of data. These are instead provided in a table in bits7..2.
> + * Bit 0 of each entry indicates whether the entry has an odd or even parity,
> + * and therefore this bytes influence on the line parity.
> + */
> +
> +#include "yportenv.h"
> +
> +#include "yaffs_ecc.h"
> +
> +static const unsigned char column_parity_table[] = {
> + 0x00, 0x55, 0x59, 0x0c, 0x65, 0x30, 0x3c, 0x69,
> + 0x69, 0x3c, 0x30, 0x65, 0x0c, 0x59, 0x55, 0x00,
> + 0x95, 0xc0, 0xcc, 0x99, 0xf0, 0xa5, 0xa9, 0xfc,
> + 0xfc, 0xa9, 0xa5, 0xf0, 0x99, 0xcc, 0xc0, 0x95,
> + 0x99, 0xcc, 0xc0, 0x95, 0xfc, 0xa9, 0xa5, 0xf0,
> + 0xf0, 0xa5, 0xa9, 0xfc, 0x95, 0xc0, 0xcc, 0x99,
> + 0x0c, 0x59, 0x55, 0x00, 0x69, 0x3c, 0x30, 0x65,
> + 0x65, 0x30, 0x3c, 0x69, 0x00, 0x55, 0x59, 0x0c,
> + 0xa5, 0xf0, 0xfc, 0xa9, 0xc0, 0x95, 0x99, 0xcc,
> + 0xcc, 0x99, 0x95, 0xc0, 0xa9, 0xfc, 0xf0, 0xa5,
> + 0x30, 0x65, 0x69, 0x3c, 0x55, 0x00, 0x0c, 0x59,
> + 0x59, 0x0c, 0x00, 0x55, 0x3c, 0x69, 0x65, 0x30,
> + 0x3c, 0x69, 0x65, 0x30, 0x59, 0x0c, 0x00, 0x55,
> + 0x55, 0x00, 0x0c, 0x59, 0x30, 0x65, 0x69, 0x3c,
> + 0xa9, 0xfc, 0xf0, 0xa5, 0xcc, 0x99, 0x95, 0xc0,
> + 0xc0, 0x95, 0x99, 0xcc, 0xa5, 0xf0, 0xfc, 0xa9,
> + 0xa9, 0xfc, 0xf0, 0xa5, 0xcc, 0x99, 0x95, 0xc0,
> + 0xc0, 0x95, 0x99, 0xcc, 0xa5, 0xf0, 0xfc, 0xa9,
> + 0x3c, 0x69, 0x65, 0x30, 0x59, 0x0c, 0x00, 0x55,
> + 0x55, 0x00, 0x0c, 0x59, 0x30, 0x65, 0x69, 0x3c,
> + 0x30, 0x65, 0x69, 0x3c, 0x55, 0x00, 0x0c, 0x59,
> + 0x59, 0x0c, 0x00, 0x55, 0x3c, 0x69, 0x65, 0x30,
> + 0xa5, 0xf0, 0xfc, 0xa9, 0xc0, 0x95, 0x99, 0xcc,
> + 0xcc, 0x99, 0x95, 0xc0, 0xa9, 0xfc, 0xf0, 0xa5,
> + 0x0c, 0x59, 0x55, 0x00, 0x69, 0x3c, 0x30, 0x65,
> + 0x65, 0x30, 0x3c, 0x69, 0x00, 0x55, 0x59, 0x0c,
> + 0x99, 0xcc, 0xc0, 0x95, 0xfc, 0xa9, 0xa5, 0xf0,
> + 0xf0, 0xa5, 0xa9, 0xfc, 0x95, 0xc0, 0xcc, 0x99,
> + 0x95, 0xc0, 0xcc, 0x99, 0xf0, 0xa5, 0xa9, 0xfc,
> + 0xfc, 0xa9, 0xa5, 0xf0, 0x99, 0xcc, 0xc0, 0x95,
> + 0x00, 0x55, 0x59, 0x0c, 0x65, 0x30, 0x3c, 0x69,
> + 0x69, 0x3c, 0x30, 0x65, 0x0c, 0x59, 0x55, 0x00,
> +};
> +
> +
> +/* Calculate the ECC for a 256-byte block of data */
> +void yaffs_ecc_cacl(const unsigned char *data, unsigned char *ecc)
> +{
> + unsigned int i;
> + unsigned char col_parity = 0;
> + unsigned char line_parity = 0;
> + unsigned char line_parity_prime = 0;
> + unsigned char t;
> + unsigned char b;
> +
> + for (i = 0; i < 256; i++) {
> + b = column_parity_table[*data++];
> + col_parity ^= b;
> +
> + if (b & 0x01) { /* odd number of bits in the byte */
> + line_parity ^= i;
> + line_parity_prime ^= ~i;
> + }
> + }
> +
> + ecc[2] = (~col_parity) | 0x03;
> +
> + t = 0;
> + if (line_parity & 0x80)
> + t |= 0x80;
> + if (line_parity_prime & 0x80)
> + t |= 0x40;
> + if (line_parity & 0x40)
> + t |= 0x20;
> + if (line_parity_prime & 0x40)
> + t |= 0x10;
> + if (line_parity & 0x20)
> + t |= 0x08;
> + if (line_parity_prime & 0x20)
> + t |= 0x04;
> + if (line_parity & 0x10)
> + t |= 0x02;
> + if (line_parity_prime & 0x10)
> + t |= 0x01;
> + ecc[1] = ~t;
> +
> + t = 0;
> + if (line_parity & 0x08)
> + t |= 0x80;
> + if (line_parity_prime & 0x08)
> + t |= 0x40;
> + if (line_parity & 0x04)
> + t |= 0x20;
> + if (line_parity_prime & 0x04)
> + t |= 0x10;
> + if (line_parity & 0x02)
> + t |= 0x08;
> + if (line_parity_prime & 0x02)
> + t |= 0x04;
> + if (line_parity & 0x01)
> + t |= 0x02;
> + if (line_parity_prime & 0x01)
> + t |= 0x01;
> + ecc[0] = ~t;
> +
> +#ifdef CONFIG_YAFFS_ECC_WRONG_ORDER
> + /* Swap the bytes into the wrong order */
> + t = ecc[0];
> + ecc[0] = ecc[1];
> + ecc[1] = t;
> +#endif
> +}
> +
> +/* Correct the ECC on a 256 byte block of data */
> +
> +int yaffs_ecc_correct(unsigned char *data, unsigned char *read_ecc,
> + const unsigned char *test_ecc)
> +{
> + unsigned char d0, d1, d2; /* deltas */
> +
> + d0 = read_ecc[0] ^ test_ecc[0];
> + d1 = read_ecc[1] ^ test_ecc[1];
> + d2 = read_ecc[2] ^ test_ecc[2];
> +
> + if ((d0 | d1 | d2) == 0)
> + return 0; /* no error */
> +
> + if (((d0 ^ (d0 >> 1)) & 0x55) == 0x55 &&
> + ((d1 ^ (d1 >> 1)) & 0x55) == 0x55 &&
> + ((d2 ^ (d2 >> 1)) & 0x54) == 0x54) {
> + /* Single bit (recoverable) error in data */
> +
> + unsigned byte;
> + unsigned bit;
> +
> +#ifdef CONFIG_YAFFS_ECC_WRONG_ORDER
> + /* swap the bytes to correct for the wrong order */
> + unsigned char t;
> +
> + t = d0;
> + d0 = d1;
> + d1 = t;
> +#endif
> +
> + bit = byte = 0;
> +
> + if (d1 & 0x80)
> + byte |= 0x80;
> + if (d1 & 0x20)
> + byte |= 0x40;
> + if (d1 & 0x08)
> + byte |= 0x20;
> + if (d1 & 0x02)
> + byte |= 0x10;
> + if (d0 & 0x80)
> + byte |= 0x08;
> + if (d0 & 0x20)
> + byte |= 0x04;
> + if (d0 & 0x08)
> + byte |= 0x02;
> + if (d0 & 0x02)
> + byte |= 0x01;
> +
> + if (d2 & 0x80)
> + bit |= 0x04;
> + if (d2 & 0x20)
> + bit |= 0x02;
> + if (d2 & 0x08)
> + bit |= 0x01;
> +
> + data[byte] ^= (1 << bit);
> +
> + return 1; /* Corrected the error */
> + }
> +
> + if ((hweight8(d0) + hweight8(d1) + hweight8(d2)) == 1) {
> + /* Reccoverable error in ecc */
> +
> + read_ecc[0] = test_ecc[0];
> + read_ecc[1] = test_ecc[1];
> + read_ecc[2] = test_ecc[2];
> +
> + return 1; /* Corrected the error */
> + }
> +
> + /* Unrecoverable error */
> +
> + return -1;

errno value?

> +}
> +
> +/*
> + * ECCxxxOther does ECC calcs on arbitrary n bytes of data
> + */
> +void yaffs_ecc_calc_other(const unsigned char *data, unsigned n_bytes,
> + struct yaffs_ecc_other *ecc_other)
> +{
> + unsigned int i;
> + unsigned char col_parity = 0;
> + unsigned line_parity = 0;
> + unsigned line_parity_prime = 0;
> + unsigned char b;
> +
> + for (i = 0; i < n_bytes; i++) {
> + b = column_parity_table[*data++];
> + col_parity ^= b;
> +
> + if (b & 0x01) {
> + /* odd number of bits in the byte */
> + line_parity ^= i;
> + line_parity_prime ^= ~i;
> + }
> +
> + }
> +
> + ecc_other->col_parity = (col_parity >> 2) & 0x3f;
> + ecc_other->line_parity = line_parity;
> + ecc_other->line_parity_prime = line_parity_prime;
> +}
> +
> +int yaffs_ecc_correct_other(unsigned char *data, unsigned n_bytes,
> + struct yaffs_ecc_other *read_ecc,
> + const struct yaffs_ecc_other *test_ecc)
> +{
> + unsigned char delta_col; /* column parity delta */
> + unsigned delta_line; /* line parity delta */
> + unsigned delta_line_prime; /* line parity delta */
> + unsigned bit;
> +
> + delta_col = read_ecc->col_parity ^ test_ecc->col_parity;
> + delta_line = read_ecc->line_parity ^ test_ecc->line_parity;
> + delta_line_prime =
> + read_ecc->line_parity_prime ^ test_ecc->line_parity_prime;
> +
> + if ((delta_col | delta_line | delta_line_prime) == 0)
> + return 0; /* no error */
> +
> + if (delta_line == ~delta_line_prime &&
> + (((delta_col ^ (delta_col >> 1)) & 0x15) == 0x15)) {
> + /* Single bit (recoverable) error in data */
> +
> + bit = 0;
> +
> + if (delta_col & 0x20)
> + bit |= 0x04;
> + if (delta_col & 0x08)
> + bit |= 0x02;
> + if (delta_col & 0x02)
> + bit |= 0x01;
> +
> + if (delta_line >= n_bytes)
> + return -1;
> +
> + data[delta_line] ^= (1 << bit);
> +
> + return 1; /* corrected */
> + }
> +
> + if ((hweight32(delta_line) +
> + hweight32(delta_line_prime) +
> + hweight8(delta_col)) == 1) {
> + /* Reccoverable error in ecc */
> +
> + *read_ecc = *test_ecc;
> + return 1; /* corrected */
> + }
> +
> + /* Unrecoverable error */
> +
> + return -1;

errno value?

> +}
> diff --git a/fs/yaffs2/yaffs_ecc.h b/fs/yaffs2/yaffs_ecc.h
> new file mode 100644
> index 0000000..a84e801
> --- /dev/null
> +++ b/fs/yaffs2/yaffs_ecc.h
> @@ -0,0 +1,44 @@
> +/*
> + * YAFFS: Yet another Flash File System . A NAND-flash specific file system.
> + *
> + * Copyright (C) 2002-2010 Aleph One Ltd.
> + * for Toby Churchill Ltd and Brightstar Engineering
> + *
> + * Created by Charles Manning <charles@xxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU Lesser General Public License version 2.1 as
> + * published by the Free Software Foundation.
> + *
> + * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
> + */
> +
> +/*
> + * This code implements the ECC algorithm used in SmartMedia.
> + *
> + * The ECC comprises 22 bits of parity information and is stuffed into 3 bytes.
> + * The two unused bit are set to 1.
> + * The ECC can correct single bit errors in a 256-byte page of data.
> + * Thus, two such ECC blocks are used on a 512-byte NAND page.
> + *
> + */
> +
> +#ifndef __YAFFS_ECC_H__
> +#define __YAFFS_ECC_H__
> +
> +struct yaffs_ecc_other {
> + unsigned char col_parity;
> + unsigned line_parity;
> + unsigned line_parity_prime;
> +};
> +
> +void yaffs_ecc_cacl(const unsigned char *data, unsigned char *ecc);
> +int yaffs_ecc_correct(unsigned char *data, unsigned char *read_ecc,
> + const unsigned char *test_ecc);
> +
> +void yaffs_ecc_calc_other(const unsigned char *data, unsigned n_bytes,
> + struct yaffs_ecc_other *ecc);
> +int yaffs_ecc_correct_other(unsigned char *data, unsigned n_bytes,
> + struct yaffs_ecc_other *read_ecc,
> + const struct yaffs_ecc_other *test_ecc);
> +#endif
> diff --git a/fs/yaffs2/yaffs_mtdif.c b/fs/yaffs2/yaffs_mtdif.c
> new file mode 100644
> index 0000000..b36a8be
> --- /dev/null
> +++ b/fs/yaffs2/yaffs_mtdif.c
> @@ -0,0 +1,53 @@
> +/*
> + * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
> + *
> + * Copyright (C) 2002-2010 Aleph One Ltd.
> + * for Toby Churchill Ltd and Brightstar Engineering
> + *
> + * Created by Charles Manning <charles@xxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include "yportenv.h"
> +
> +#include "yaffs_mtdif.h"
> +
> +#include "linux/mtd/mtd.h"
> +#include "linux/types.h"
> +#include "linux/time.h"
> +#include "linux/mtd/nand.h"
> +
> +#include "yaffs_linux.h"
> +
> +int nandmtd_erase_block(struct yaffs_dev *dev, int block_no)
> +{
> + struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
> + u32 addr =
> + ((loff_t) block_no) * dev->param.total_bytes_per_chunk
> + * dev->param.chunks_per_block;
> + struct erase_info ei;
> + int retval = 0;
> +
> + ei.mtd = mtd;
> + ei.addr = addr;
> + ei.len = dev->param.total_bytes_per_chunk * dev->param.chunks_per_block;
> + ei.time = 1000;
> + ei.retries = 2;
> + ei.callback = NULL;
> + ei.priv = (u_long) dev;

Nitpick: Casts should be written like this:

ei.prov = (u_long)dev;

This applies across the whole patch series.

> +
> + retval = mtd->erase(mtd, &ei);
> +
> + if (retval == 0)
> + return YAFFS_OK;
> + else
> + return YAFFS_FAIL;
> +}
> +
> +int nandmtd_initialise(struct yaffs_dev *dev)
> +{
> + return YAFFS_OK;
> +}
> diff --git a/fs/yaffs2/yaffs_mtdif.h b/fs/yaffs2/yaffs_mtdif.h
> new file mode 100644
> index 0000000..6665074
> --- /dev/null
> +++ b/fs/yaffs2/yaffs_mtdif.h
> @@ -0,0 +1,23 @@
> +/*
> + * YAFFS: Yet another Flash File System . A NAND-flash specific file system.
> + *
> + * Copyright (C) 2002-2010 Aleph One Ltd.
> + * for Toby Churchill Ltd and Brightstar Engineering
> + *
> + * Created by Charles Manning <charles@xxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU Lesser General Public License version 2.1 as
> + * published by the Free Software Foundation.
> + *
> + * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
> + */
> +
> +#ifndef __YAFFS_MTDIF_H__
> +#define __YAFFS_MTDIF_H__
> +
> +#include "yaffs_guts.h"
> +
> +int nandmtd_erase_block(struct yaffs_dev *dev, int block_no);
> +int nandmtd_initialise(struct yaffs_dev *dev);
> +#endif
> diff --git a/fs/yaffs2/yaffs_mtdif1.c b/fs/yaffs2/yaffs_mtdif1.c
> new file mode 100644
> index 0000000..182870c
> --- /dev/null
> +++ b/fs/yaffs2/yaffs_mtdif1.c
> @@ -0,0 +1,329 @@
> +/*
> + * YAFFS: Yet another FFS. A NAND-flash specific file system.
> + *
> + * Copyright (C) 2002-2010 Aleph One Ltd.
> + * for Toby Churchill Ltd and Brightstar Engineering
> + *
> + * Created by Charles Manning <charles@xxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +/*
> + * This module provides the interface between yaffs_nand.c and the
> + * MTD API. This version is used when the MTD interface supports the
> + * 'mtd_oob_ops' style calls to read_oob and write_oob, circa 2.6.17,
> + * and we have small-page NAND device.
> + *
> + * These functions are invoked via function pointers in yaffs_nand.c.
> + * This replaces functionality provided by functions in yaffs_mtdif.c
> + * and the yaffs_tags compatability functions in yaffs_tagscompat.c that are
> + * called in yaffs_mtdif.c when the function pointers are NULL.
> + * We assume the MTD layer is performing ECC (use_nand_ecc is true).
> + */
> +
> +#include "yportenv.h"
> +#include "yaffs_trace.h"
> +#include "yaffs_guts.h"
> +#include "yaffs_packedtags1.h"
> +#include "yaffs_tagscompat.h" /* for yaffs_calc_tags_ecc */
> +#include "yaffs_linux.h"
> +#include "linux/kernel.h"
> +#include "linux/version.h"
> +#include "linux/types.h"
> +#include "linux/mtd/mtd.h"
> +
> +#ifndef CONFIG_YAFFS_9BYTE_TAGS
> +# define YTAG1_SIZE 8
> +#else
> +# define YTAG1_SIZE 9
> +#endif
> +
> +/* Write a chunk (page) of data to NAND.
> + *
> + * Caller always provides ExtendedTags data which are converted to a more
> + * compact (packed) form for storage in NAND. A mini-ECC runs over the
> + * contents of the tags meta-data; used to valid the tags when read.
> + *
> + * - Pack ExtendedTags to packed_tags1 form
> + * - Compute mini-ECC for packed_tags1
> + * - Write data and packed tags to NAND.
> + *
> + * Note: Due to the use of the packed_tags1 meta-data which does not include
> + * a full sequence number (as found in the larger packed_tags2 form) it is
> + * necessary for Yaffs to re-write a chunk/page (just once) to mark it as
> + * discarded and dirty. This is not ideal: newer NAND parts are supposed
> + * to be written just once. When Yaffs performs this operation, this
> + * function is called with a NULL data pointer -- calling MTD write_oob
> + * without data is valid usage (2.6.17).
> + *
> + * Any underlying MTD error results in YAFFS_FAIL.
> + * Returns YAFFS_OK or YAFFS_FAIL.
> + */
> +int nandmtd1_write_chunk_tags(struct yaffs_dev *dev,
> + int nand_chunk, const u8 *data,
> + const struct yaffs_ext_tags *etags)
> +{
> + struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
> + int chunk_bytes = dev->data_bytes_per_chunk;
> + loff_t addr = ((loff_t) nand_chunk) * chunk_bytes;
> + struct mtd_oob_ops ops;
> + struct yaffs_packed_tags1 pt1;
> + int retval;
> +
> + /* we assume that packed_tags1 and struct yaffs_tags are compatible */
> + compile_time_assertion(sizeof(struct yaffs_packed_tags1) == 12);
> + compile_time_assertion(sizeof(struct yaffs_tags) == 8);

Can use one of the BUILD_BUG_ON macros rather than rolling your own?

> +
> + yaffs_pack_tags1(&pt1, etags);
> + yaffs_calc_tags_ecc((struct yaffs_tags *)&pt1);
> +
> + /* When deleting a chunk, the upper layer provides only skeletal
> + * etags, one with is_deleted set. However, we need to update the
> + * tags, not erase them completely. So we use the NAND write property
> + * that only zeroed-bits stick and set tag bytes to all-ones and
> + * zero just the (not) deleted bit.
> + */
> +#ifndef CONFIG_YAFFS_9BYTE_TAGS
> + if (etags->is_deleted) {
> + memset(&pt1, 0xff, 8);
> + /* clear delete status bit to indicate deleted */
> + pt1.deleted = 0;
> + }
> +#else
> + ((u8 *) &pt1)[8] = 0xff;
> + if (etags->is_deleted) {
> + memset(&pt1, 0xff, 8);
> + /* zero page_status byte to indicate deleted */
> + ((u8 *) &pt1)[8] = 0;
> + }
> +#endif
> +
> + memset(&ops, 0, sizeof(ops));
> + ops.mode = MTD_OOB_AUTO;
> + ops.len = (data) ? chunk_bytes : 0;
> + ops.ooblen = YTAG1_SIZE;
> + ops.datbuf = (u8 *) data;
> + ops.oobbuf = (u8 *) &pt1;
> +
> + retval = mtd->write_oob(mtd, addr, &ops);
> + if (retval) {
> + yaffs_trace(YAFFS_TRACE_MTD,
> + "write_oob failed, chunk %d, mtd error %d",
> + nand_chunk, retval);
> + }
> + return retval ? YAFFS_FAIL : YAFFS_OK;
> +}
> +
> +/* Return with empty ExtendedTags but add ecc_result.
> + */
> +static int rettags(struct yaffs_ext_tags *etags, int ecc_result, int retval)
> +{
> + if (etags) {
> + memset(etags, 0, sizeof(*etags));
> + etags->ecc_result = ecc_result;
> + }
> + return retval;
> +}
> +
> +/* Read a chunk (page) from NAND.
> + *
> + * Caller expects ExtendedTags data to be usable even on error; that is,
> + * all members except ecc_result and block_bad are zeroed.
> + *
> + * - Check ECC results for data (if applicable)
> + * - Check for blank/erased block (return empty ExtendedTags if blank)
> + * - Check the packed_tags1 mini-ECC (correct if necessary/possible)
> + * - Convert packed_tags1 to ExtendedTags
> + * - Update ecc_result and block_bad members to refect state.
> + *
> + * Returns YAFFS_OK or YAFFS_FAIL.
> + */
> +int nandmtd1_read_chunk_tags(struct yaffs_dev *dev,
> + int nand_chunk, u8 *data,
> + struct yaffs_ext_tags *etags)
> +{
> + struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
> + int chunk_bytes = dev->data_bytes_per_chunk;
> + loff_t addr = ((loff_t) nand_chunk) * chunk_bytes;
> + int eccres = YAFFS_ECC_RESULT_NO_ERROR;
> + struct mtd_oob_ops ops;

Change this to:

struct mtd_oob_ops ops = {0};

> + struct yaffs_packed_tags1 pt1;
> + int retval;
> + int deleted;
> +
> + memset(&ops, 0, sizeof(ops));

and then remove this memset.

> + ops.mode = MTD_OOB_AUTO;
> + ops.len = (data) ? chunk_bytes : 0;
> + ops.ooblen = YTAG1_SIZE;
> + ops.datbuf = data;
> + ops.oobbuf = (u8 *) &pt1;
> +
> + /* Read page and oob using MTD.
> + * Check status and determine ECC result.
> + */
> + retval = mtd->read_oob(mtd, addr, &ops);
> + if (retval) {
> + yaffs_trace(YAFFS_TRACE_MTD,
> + "read_oob failed, chunk %d, mtd error %d",
> + nand_chunk, retval);
> + }
> +
> + switch (retval) {
> + case 0:
> + /* no error */
> + break;
> +
> + case -EUCLEAN:
> + /* MTD's ECC fixed the data */
> + eccres = YAFFS_ECC_RESULT_FIXED;
> + dev->n_ecc_fixed++;
> + break;
> +
> + case -EBADMSG:
> + /* MTD's ECC could not fix the data */
> + dev->n_ecc_unfixed++;
> + /* fall into... */
> + default:
> + rettags(etags, YAFFS_ECC_RESULT_UNFIXED, 0);
> + etags->block_bad = (mtd->block_isbad) (mtd, addr);
> + return YAFFS_FAIL;
> + }
> +
> + /* Check for a blank/erased chunk.
> + */
> + if (yaffs_check_ff((u8 *) &pt1, 8)) {
> + /* when blank, upper layers want ecc_result to be <= NO_ERROR */
> + return rettags(etags, YAFFS_ECC_RESULT_NO_ERROR, YAFFS_OK);
> + }
> +#ifndef CONFIG_YAFFS_9BYTE_TAGS
> + /* Read deleted status (bit) then return it to it's non-deleted
> + * state before performing tags mini-ECC check. pt1.deleted is
> + * inverted.
> + */
> + deleted = !pt1.deleted;
> + pt1.deleted = 1;
> +#else
> + deleted = (hweight8(((u8 *) &pt1)[8]) < 7);
> +#endif
> +
> + /* Check the packed tags mini-ECC and correct if necessary/possible.
> + */
> + retval = yaffs_check_tags_ecc((struct yaffs_tags *)&pt1);
> + switch (retval) {
> + case 0:
> + /* no tags error, use MTD result */
> + break;
> + case 1:
> + /* recovered tags-ECC error */
> + dev->n_tags_ecc_fixed++;
> + if (eccres == YAFFS_ECC_RESULT_NO_ERROR)
> + eccres = YAFFS_ECC_RESULT_FIXED;
> + break;
> + default:
> + /* unrecovered tags-ECC error */
> + dev->n_tags_ecc_unfixed++;
> + return rettags(etags, YAFFS_ECC_RESULT_UNFIXED, YAFFS_FAIL);
> + }
> +
> + /* Unpack the tags to extended form and set ECC result.
> + * [set should_be_ff just to keep yaffs_unpack_tags1 happy]
> + */
> + pt1.should_be_ff = 0xFFFFFFFF;
> + yaffs_unpack_tags1(etags, &pt1);
> + etags->ecc_result = eccres;
> +
> + /* Set deleted state */
> + etags->is_deleted = deleted;
> + return YAFFS_OK;
> +}
> +
> +/* Mark a block bad.
> + *
> + * This is a persistant state.
> + * Use of this function should be rare.
> + *
> + * Returns YAFFS_OK or YAFFS_FAIL.
> + */
> +int nandmtd1_mark_block_bad(struct yaffs_dev *dev, int block_no)
> +{
> + struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
> + int blocksize = dev->param.chunks_per_block * dev->data_bytes_per_chunk;
> + int retval;
> +
> + yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
> + "marking block %d bad", block_no);
> +
> + retval = mtd->block_markbad(mtd, (loff_t) blocksize * block_no);
> + return (retval) ? YAFFS_FAIL : YAFFS_OK;
> +}
> +
> +/* Check any MTD prerequists.
> + *
> + * Returns YAFFS_OK or YAFFS_FAIL.
> + */
> +static int nandmtd1_test_prerequists(struct mtd_info *mtd)
> +{
> + /* 2.6.18 has mtd->ecclayout->oobavail */
> + /* 2.6.21 has mtd->ecclayout->oobavail and mtd->oobavail */

This comment is not applicable for mainline.

> + int oobavail = mtd->ecclayout->oobavail;
> +
> + if (oobavail < YTAG1_SIZE) {
> + yaffs_trace(YAFFS_TRACE_ERROR,
> + "mtd device has only %d bytes for tags, need %d",
> + oobavail, YTAG1_SIZE);
> + return YAFFS_FAIL;
> + }
> + return YAFFS_OK;
> +}
> +
> +/* Query for the current state of a specific block.
> + *
> + * Examine the tags of the first chunk of the block and return the state:
> + * - YAFFS_BLOCK_STATE_DEAD, the block is marked bad
> + * - YAFFS_BLOCK_STATE_NEEDS_SCANNING, the block is in use
> + * - YAFFS_BLOCK_STATE_EMPTY, the block is clean
> + *
> + * Always returns YAFFS_OK.
> + */
> +int nandmtd1_query_block(struct yaffs_dev *dev, int block_no,
> + enum yaffs_block_state *state_ptr, u32 * seq_ptr)
> +{
> + struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
> + int chunk_num = block_no * dev->param.chunks_per_block;
> + loff_t addr = (loff_t) chunk_num * dev->data_bytes_per_chunk;
> + struct yaffs_ext_tags etags;
> + int state = YAFFS_BLOCK_STATE_DEAD;
> + int seqnum = 0;
> + int retval;
> +
> + /* We don't yet have a good place to test for MTD config prerequists.
> + * Do it here as we are called during the initial scan.
> + */
> + if (nandmtd1_test_prerequists(mtd) != YAFFS_OK)
> + return YAFFS_FAIL;
> +
> + retval = nandmtd1_read_chunk_tags(dev, chunk_num, NULL, &etags);
> + etags.block_bad = (mtd->block_isbad) (mtd, addr);
> + if (etags.block_bad) {
> + yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
> + "block %d is marked bad", block_no);
> + state = YAFFS_BLOCK_STATE_DEAD;
> + } else if (etags.ecc_result != YAFFS_ECC_RESULT_NO_ERROR) {
> + /* bad tags, need to look more closely */
> + state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
> + } else if (etags.chunk_used) {
> + state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
> + seqnum = etags.seq_number;
> + } else {
> + state = YAFFS_BLOCK_STATE_EMPTY;
> + }
> +
> + *state_ptr = state;
> + *seq_ptr = seqnum;
> +
> + /* query always succeeds */
> + return YAFFS_OK;
> +}
> diff --git a/fs/yaffs2/yaffs_mtdif1.h b/fs/yaffs2/yaffs_mtdif1.h
> new file mode 100644
> index 0000000..034c680
> --- /dev/null
> +++ b/fs/yaffs2/yaffs_mtdif1.h
> @@ -0,0 +1,29 @@
> +/*
> + * YAFFS: Yet another Flash File System. A NAND-flash specific file system.
> + *
> + * Copyright (C) 2002-2010 Aleph One Ltd.
> + * for Toby Churchill Ltd and Brightstar Engineering
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU Lesser General Public License version 2.1 as
> + * published by the Free Software Foundation.
> + *
> + * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
> + */
> +
> +#ifndef __YAFFS_MTDIF1_H__
> +#define __YAFFS_MTDIF1_H__
> +
> +int nandmtd1_write_chunk_tags(struct yaffs_dev *dev, int nand_chunk,
> + const u8 *data,
> + const struct yaffs_ext_tags *tags);
> +
> +int nandmtd1_read_chunk_tags(struct yaffs_dev *dev, int nand_chunk,
> + u8 *data, struct yaffs_ext_tags *tags);
> +
> +int nandmtd1_mark_block_bad(struct yaffs_dev *dev, int block_no);
> +
> +int nandmtd1_query_block(struct yaffs_dev *dev, int block_no,
> + enum yaffs_block_state *state, u32 *seq_number);
> +
> +#endif
> diff --git a/fs/yaffs2/yaffs_mtdif2.c b/fs/yaffs2/yaffs_mtdif2.c
> new file mode 100644
> index 0000000..18340bd
> --- /dev/null
> +++ b/fs/yaffs2/yaffs_mtdif2.c
> @@ -0,0 +1,215 @@
> +/*
> + * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
> + *
> + * Copyright (C) 2002-2010 Aleph One Ltd.
> + * for Toby Churchill Ltd and Brightstar Engineering
> + *
> + * Created by Charles Manning <charles@xxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +/* mtd interface for YAFFS2 */
> +
> +#include "yportenv.h"
> +#include "yaffs_trace.h"
> +#include "yaffs_mtdif2.h"
> +#include "yaffs_packedtags2.h"
> +#include "yaffs_linux.h"
> +#include "linux/mtd/mtd.h"
> +#include "linux/types.h"
> +#include "linux/time.h"
> +
> +
> +/* NB For use with inband tags....
> + * We assume that the data buffer is of size total_bytes_per_chunk so that
> + * we can also use it to load the tags.
> + */
> +int nandmtd2_write_chunk_tags(struct yaffs_dev *dev, int nand_chunk,
> + const u8 *data,
> + const struct yaffs_ext_tags *tags)
> +{
> + struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
> + struct mtd_oob_ops ops;
> + int retval = 0;
> + loff_t addr;
> + struct yaffs_packed_tags2 pt;
> + int packed_tags_size =
> + dev->param.no_tags_ecc ? sizeof(pt.t) : sizeof(pt);
> + void *packed_tags_ptr =
> + dev->param.no_tags_ecc ? (void *)&pt.t : (void *)&pt;

Shouldn't need void * casts.

> +
> + yaffs_trace(YAFFS_TRACE_MTD,
> + "nandmtd2_write_chunk_tags chunk %d data %p tags %p",
> + nand_chunk, data, tags);
> +
> + addr = ((loff_t) nand_chunk) * dev->param.total_bytes_per_chunk;
> +
> + /* For yaffs2 writing there must be both data and tags.
> + * If we're using inband tags, then the tags are stuffed into
> + * the end of the data buffer.
> + */
> + if (!data || !tags)
> + BUG();
> + else if (dev->param.inband_tags) {

This should be a separate if statement to the one for BUG. If you don't
want fall through when BUG is not enabled, then just have:

if (!data || !tags) {
BUG();
return YAFFS_FAILED;
}

> + struct yaffs_packed_tags2_tags_only *pt2tp;
> +
> + pt2tp =
> + (struct yaffs_packed_tags2_tags_only *)(data +
> + dev->
> + data_bytes_per_chunk);
> + yaffs_pack_tags2_tags_only(pt2tp, tags);
> + } else {
> + yaffs_pack_tags2(&pt, tags, !dev->param.no_tags_ecc);
> + }
> +
> + ops.mode = MTD_OOB_AUTO;
> + ops.ooblen = (dev->param.inband_tags) ? 0 : packed_tags_size;
> + ops.len = dev->param.total_bytes_per_chunk;
> + ops.ooboffs = 0;
> + ops.datbuf = (u8 *) data;
> + ops.oobbuf = (dev->param.inband_tags) ? NULL : packed_tags_ptr;
> + retval = mtd->write_oob(mtd, addr, &ops);
> +
> + if (retval == 0)
> + return YAFFS_OK;
> + else
> + return YAFFS_FAIL;
> +}
> +
> +int nandmtd2_read_chunk_tags(struct yaffs_dev *dev, int nand_chunk,
> + u8 *data, struct yaffs_ext_tags *tags)
> +{
> + struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
> + struct mtd_oob_ops ops;
> + size_t dummy;
> + int retval = 0;
> + int local_data = 0;
> + loff_t addr = ((loff_t) nand_chunk) * dev->param.total_bytes_per_chunk;
> + struct yaffs_packed_tags2 pt;
> + int packed_tags_size =
> + dev->param.no_tags_ecc ? sizeof(pt.t) : sizeof(pt);
> + void *packed_tags_ptr =
> + dev->param.no_tags_ecc ? (void *)&pt.t : (void *)&pt;

Shouldn't need void * casts.

> + yaffs_trace(YAFFS_TRACE_MTD,
> + "nandmtd2_read_chunk_tags chunk %d data %p tags %p",
> + nand_chunk, data, tags);
> +
> + if (dev->param.inband_tags) {
> +
> + if (!data) {

if (dev->param.inband_tags && !data) ?

> + local_data = 1;
> + data = yaffs_get_temp_buffer(dev, __LINE__);
> + }
> + }
> +
> + if (dev->param.inband_tags || (data && !tags))
> + retval = mtd->read(mtd, addr, dev->param.total_bytes_per_chunk,
> + &dummy, data);
> + else if (tags) {
> + ops.mode = MTD_OOB_AUTO;
> + ops.ooblen = packed_tags_size;
> + ops.len = data ? dev->data_bytes_per_chunk : packed_tags_size;
> + ops.ooboffs = 0;
> + ops.datbuf = data;
> + ops.oobbuf = yaffs_dev_to_lc(dev)->spare_buffer;
> + retval = mtd->read_oob(mtd, addr, &ops);
> + }
> +
> + if (dev->param.inband_tags) {
> + if (tags) {
> + struct yaffs_packed_tags2_tags_only *pt2tp;
> + pt2tp =
> + (struct yaffs_packed_tags2_tags_only *)
> + &data[dev->data_bytes_per_chunk];
> + yaffs_unpack_tags2_tags_only(tags, pt2tp);
> + }
> + } else {
> + if (tags) {
> + memcpy(packed_tags_ptr,
> + yaffs_dev_to_lc(dev)->spare_buffer,
> + packed_tags_size);
> + yaffs_unpack_tags2(tags, &pt, !dev->param.no_tags_ecc);
> + }
> + }
> +
> + if (local_data)
> + yaffs_release_temp_buffer(dev, data, __LINE__);
> +
> + if (tags && retval == -EBADMSG
> + && tags->ecc_result == YAFFS_ECC_RESULT_NO_ERROR) {
> + tags->ecc_result = YAFFS_ECC_RESULT_UNFIXED;
> + dev->n_ecc_unfixed++;
> + }
> + if (tags && retval == -EUCLEAN
> + && tags->ecc_result == YAFFS_ECC_RESULT_NO_ERROR) {
> + tags->ecc_result = YAFFS_ECC_RESULT_FIXED;
> + dev->n_ecc_fixed++;
> + }
> + if (retval == 0)
> + return YAFFS_OK;
> + else
> + return YAFFS_FAIL;
> +}
> +
> +int nandmtd2_mark_block_bad(struct yaffs_dev *dev, int block_no)
> +{
> + struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
> + int retval;
> +
> + yaffs_trace(YAFFS_TRACE_MTD,
> + "nandmtd2_mark_block_bad %d", block_no);
> +
> + retval =
> + mtd->block_markbad(mtd,
> + block_no * dev->param.chunks_per_block *
> + dev->param.total_bytes_per_chunk);
> +
> + if (retval == 0)
> + return YAFFS_OK;
> + else
> + return YAFFS_FAIL;
> +}
> +
> +int nandmtd2_query_block(struct yaffs_dev *dev, int block_no,
> + enum yaffs_block_state *state, u32 * seq_number)
> +{
> + struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
> + int retval;
> +
> + yaffs_trace(YAFFS_TRACE_MTD, "nandmtd2_query_block %d", block_no);
> + retval =
> + mtd->block_isbad(mtd,
> + block_no * dev->param.chunks_per_block *
> + dev->param.total_bytes_per_chunk);
> +
> + if (retval) {
> + yaffs_trace(YAFFS_TRACE_MTD, "block is bad");
> +
> + *state = YAFFS_BLOCK_STATE_DEAD;
> + *seq_number = 0;
> + } else {
> + struct yaffs_ext_tags t;
> + nandmtd2_read_chunk_tags(dev, block_no *
> + dev->param.chunks_per_block, NULL, &t);
> +
> + if (t.chunk_used) {
> + *seq_number = t.seq_number;
> + *state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
> + } else {
> + *seq_number = 0;
> + *state = YAFFS_BLOCK_STATE_EMPTY;
> + }
> + }
> + yaffs_trace(YAFFS_TRACE_MTD,
> + "block is bad seq %d state %d", *seq_number, *state);
> +
> + if (retval == 0)
> + return YAFFS_OK;
> + else
> + return YAFFS_FAIL;
> +}
> +
> diff --git a/fs/yaffs2/yaffs_mtdif2.h b/fs/yaffs2/yaffs_mtdif2.h
> new file mode 100644
> index 0000000..78babf5
> --- /dev/null
> +++ b/fs/yaffs2/yaffs_mtdif2.h
> @@ -0,0 +1,29 @@
> +/*
> + * YAFFS: Yet another Flash File System . A NAND-flash specific file system.
> + *
> + * Copyright (C) 2002-2010 Aleph One Ltd.
> + * for Toby Churchill Ltd and Brightstar Engineering
> + *
> + * Created by Charles Manning <charles@xxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU Lesser General Public License version 2.1 as
> + * published by the Free Software Foundation.
> + *
> + * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
> + */
> +
> +#ifndef __YAFFS_MTDIF2_H__
> +#define __YAFFS_MTDIF2_H__
> +
> +#include "yaffs_guts.h"
> +int nandmtd2_write_chunk_tags(struct yaffs_dev *dev, int nand_chunk,
> + const u8 *data,
> + const struct yaffs_ext_tags *tags);
> +int nandmtd2_read_chunk_tags(struct yaffs_dev *dev, int nand_chunk,
> + u8 *data, struct yaffs_ext_tags *tags);
> +int nandmtd2_mark_block_bad(struct yaffs_dev *dev, int block_no);
> +int nandmtd2_query_block(struct yaffs_dev *dev, int block_no,
> + enum yaffs_block_state *state, u32 *seq_number);
> +
> +#endif
> diff --git a/fs/yaffs2/yaffs_nand.c b/fs/yaffs2/yaffs_nand.c
> new file mode 100644
> index 0000000..ee061a8
> --- /dev/null
> +++ b/fs/yaffs2/yaffs_nand.c
> @@ -0,0 +1,120 @@
> +/*
> + * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
> + *
> + * Copyright (C) 2002-2010 Aleph One Ltd.
> + * for Toby Churchill Ltd and Brightstar Engineering
> + *
> + * Created by Charles Manning <charles@xxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include "yaffs_nand.h"
> +#include "yaffs_tagscompat.h"
> +#include "yaffs_tagsvalidity.h"
> +
> +#include "yaffs_getblockinfo.h"
> +
> +int yaffs_rd_chunk_tags_nand(struct yaffs_dev *dev, int nand_chunk,
> + u8 *buffer, struct yaffs_ext_tags *tags)
> +{
> + int result;
> + struct yaffs_ext_tags local_tags;
> + int realigned_chunk = nand_chunk - dev->chunk_offset;
> +
> + dev->n_page_reads++;
> +
> + /* If there are no tags provided use local tags. */
> + if (!tags)
> + tags = &local_tags;
> +
> + if (dev->param.read_chunk_tags_fn)
> + result =
> + dev->param.read_chunk_tags_fn(dev, realigned_chunk, buffer,
> + tags);
> + else
> + result = yaffs_tags_compat_rd(dev,
> + realigned_chunk, buffer, tags);
> + if (tags && tags->ecc_result > YAFFS_ECC_RESULT_NO_ERROR) {
> +
> + struct yaffs_block_info *bi;
> + bi = yaffs_get_block_info(dev,
> + nand_chunk /
> + dev->param.chunks_per_block);
> + yaffs_handle_chunk_error(dev, bi);
> + }
> + return result;
> +}
> +
> +int yaffs_wr_chunk_tags_nand(struct yaffs_dev *dev,
> + int nand_chunk,
> + const u8 *buffer, struct yaffs_ext_tags *tags)
> +{
> + dev->n_page_writes++;
> + nand_chunk -= dev->chunk_offset;
> +
> + if (tags) {
> + tags->seq_number = dev->seq_number;
> + tags->chunk_used = 1;
> + if (!yaffs_validate_tags(tags)) {
> + yaffs_trace(YAFFS_TRACE_ERROR,
> + "Writing uninitialised tags");
> + YBUG();
> + }
> + yaffs_trace(YAFFS_TRACE_WRITE,
> + "Writing chunk %d tags %d %d",
> + nand_chunk, tags->obj_id, tags->chunk_id);
> + } else {
> + yaffs_trace(YAFFS_TRACE_ERROR, "Writing with no tags");
> + YBUG();
> + return YAFFS_FAIL;
> + }

I would rearrange this to make the BUG case prominent and then drop the
indentation for the case where tags is valid, ie:

if (!tags) {
yaffs_trace(YAFFS_TRACE_ERROR, "Writing with no tags");
YBUG();
return YAFFS_FAIL;
}

tags->seq_number = dev->seq_number;
...

> +
> + if (dev->param.write_chunk_tags_fn)
> + return dev->param.write_chunk_tags_fn(dev, nand_chunk, buffer,
> + tags);
> + else
> + return yaffs_tags_compat_wr(dev, nand_chunk, buffer, tags);
> +}
> +
> +int yaffs_mark_bad(struct yaffs_dev *dev, int block_no)
> +{
> + block_no -= dev->block_offset;
> + if (dev->param.bad_block_fn)
> + return dev->param.bad_block_fn(dev, block_no);
> + else
> + return yaffs_tags_compat_mark_bad(dev, block_no);
> +}
> +
> +int yaffs_query_init_block_state(struct yaffs_dev *dev,
> + int block_no,
> + enum yaffs_block_state *state,
> + u32 *seq_number)
> +{
> + block_no -= dev->block_offset;
> + if (dev->param.query_block_fn)
> + return dev->param.query_block_fn(dev, block_no, state,
> + seq_number);
> + else
> + return yaffs_tags_compat_query_block(dev, block_no,
> + state, seq_number);
> +}
> +
> +int yaffs_erase_block(struct yaffs_dev *dev, int flash_block)
> +{
> + int result;
> +
> + flash_block -= dev->block_offset;
> + dev->n_erasures++;
> + result = dev->param.erase_fn(dev, flash_block);
> + return result;

Just:
return dev->param.erase_fn(dev, flash_block);

> +}
> +
> +int yaffs_init_nand(struct yaffs_dev *dev)
> +{
> + if (dev->param.initialise_flash_fn)
> + return dev->param.initialise_flash_fn(dev);
> + return YAFFS_OK;
> +}
> diff --git a/fs/yaffs2/yaffs_nand.h b/fs/yaffs2/yaffs_nand.h
> new file mode 100644
> index 0000000..a36498a
> --- /dev/null
> +++ b/fs/yaffs2/yaffs_nand.h
> @@ -0,0 +1,38 @@
> +/*
> + * YAFFS: Yet another Flash File System . A NAND-flash specific file system.
> + *
> + * Copyright (C) 2002-2010 Aleph One Ltd.
> + * for Toby Churchill Ltd and Brightstar Engineering
> + *
> + * Created by Charles Manning <charles@xxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU Lesser General Public License version 2.1 as
> + * published by the Free Software Foundation.
> + *
> + * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
> + */
> +
> +#ifndef __YAFFS_NAND_H__
> +#define __YAFFS_NAND_H__
> +#include "yaffs_guts.h"
> +
> +int yaffs_rd_chunk_tags_nand(struct yaffs_dev *dev, int nand_chunk,
> + u8 *buffer, struct yaffs_ext_tags *tags);
> +
> +int yaffs_wr_chunk_tags_nand(struct yaffs_dev *dev,
> + int nand_chunk,
> + const u8 *buffer, struct yaffs_ext_tags *tags);
> +
> +int yaffs_mark_bad(struct yaffs_dev *dev, int block_no);
> +
> +int yaffs_query_init_block_state(struct yaffs_dev *dev,
> + int block_no,
> + enum yaffs_block_state *state,
> + unsigned *seq_number);
> +
> +int yaffs_erase_block(struct yaffs_dev *dev, int flash_block);
> +
> +int yaffs_init_nand(struct yaffs_dev *dev);
> +
> +#endif

--
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ryan@xxxxxxxxxxxxxxxx PO Box 13 889, Christchurch 8013
http://www.bluewatersys.com New Zealand
Phone: +64 3 3779127 Freecall: Australia 1800 148 751
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