2 * YAFFS: Yet another FFS. A NAND-flash specific file system.
4 * Copyright (C) 2002-2011 Aleph One Ltd.
5 * for Toby Churchill Ltd and Brightstar Engineering
7 * Created by Charles Manning <charles@aleph1.co.uk>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
15 * This module provides the interface between yaffs_nand.c and the
16 * MTD API. This version is used when the MTD interface supports the
17 * 'mtd_oob_ops' style calls to read_oob and write_oob, circa 2.6.17,
18 * and we have small-page NAND device.
20 * These functions are invoked via function pointers in yaffs_nand.c.
21 * This replaces functionality provided by functions in yaffs_mtdif.c
22 * and the yaffs_tags compatability functions in yaffs_tagscompat.c that are
23 * called in yaffs_mtdif.c when the function pointers are NULL.
24 * We assume the MTD layer is performing ECC (use_nand_ecc is true).
28 #include "yaffs_trace.h"
29 #include "yaffs_guts.h"
30 #include "yaffs_packedtags1.h"
31 #include "yaffs_tagscompat.h" /* for yaffs_calc_tags_ecc */
32 #include "yaffs_linux.h"
34 #include "linux/kernel.h"
35 #include "linux/version.h"
36 #include "linux/types.h"
37 #include "linux/mtd/mtd.h"
39 /* Don't compile this module if we don't have MTD's mtd_oob_ops interface */
40 #if (MTD_VERSION_CODE > MTD_VERSION(2, 6, 17))
44 /* Use the following nand_ecclayout with MTD when using
45 * 9 byte tags and the older on-NAND tags layout.
46 * If you have existing Yaffs images and the byte order differs from this,
47 * adjust 'oobfree' to match your existing Yaffs data.
49 * This nand_ecclayout scatters/gathers to/from the old-yaffs layout with the
50 * page_status byte (at NAND spare offset 4) scattered/gathered from/to
53 * Old-style on-NAND format: T0,T1,T2,T3,P,B,T4,T5,E0,E1,E2,T6,T7,E3,E4,E5
54 * We have/need packed_tags1 plus page_status: T0,T1,T2,T3,T4,T5,T6,T7,P
55 * where Tn are the tag bytes, En are MTD's ECC bytes, P is the page_status
56 * byte and B is the small-page bad-block indicator byte.
58 static struct nand_ecclayout nand_oob_16 = {
60 .eccpos = {8, 9, 10, 13, 14, 15},
62 .oobfree = {{0, 4}, {6, 2}, {11, 2}, {4, 1} }
66 /* Write a chunk (page) of data to NAND.
68 * Caller always provides ExtendedTags data which are converted to a more
69 * compact (packed) form for storage in NAND. A mini-ECC runs over the
70 * contents of the tags meta-data; used to valid the tags when read.
72 * - Pack ExtendedTags to packed_tags1 form
73 * - Compute mini-ECC for packed_tags1
74 * - Write data and packed tags to NAND.
76 * Note: Due to the use of the packed_tags1 meta-data which does not include
77 * a full sequence number (as found in the larger packed_tags2 form) it is
78 * necessary for Yaffs to re-write a chunk/page (just once) to mark it as
79 * discarded and dirty. This is not ideal: newer NAND parts are supposed
80 * to be written just once. When Yaffs performs this operation, this
81 * function is called with a NULL data pointer -- calling MTD write_oob
82 * without data is valid usage (2.6.17).
84 * Any underlying MTD error results in YAFFS_FAIL.
85 * Returns YAFFS_OK or YAFFS_FAIL.
87 int nandmtd1_write_chunk_tags(struct yaffs_dev *dev,
88 int nand_chunk, const u8 *data,
89 const struct yaffs_ext_tags *etags)
91 struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
92 int chunk_bytes = dev->data_bytes_per_chunk;
93 loff_t addr = ((loff_t) nand_chunk) * chunk_bytes;
94 struct mtd_oob_ops ops;
95 struct yaffs_packed_tags1 pt1;
98 /* we assume that packed_tags1 and struct yaffs_tags are compatible */
99 compile_time_assertion(sizeof(struct yaffs_packed_tags1) == 12);
100 compile_time_assertion(sizeof(struct yaffs_tags) == 8);
102 yaffs_pack_tags1(&pt1, etags);
103 yaffs_calc_tags_ecc((struct yaffs_tags *)&pt1);
105 /* When deleting a chunk, the upper layer provides only skeletal
106 * etags, one with is_deleted set. However, we need to update the
107 * tags, not erase them completely. So we use the NAND write property
108 * that only zeroed-bits stick and set tag bytes to all-ones and
109 * zero just the (not) deleted bit.
111 if(dev->param.tags_9bytes) {
112 ((u8 *) &pt1)[8] = 0xff;
113 if (etags->is_deleted) {
114 memset(&pt1, 0xff, 8);
115 /* zero page_status byte to indicate deleted */
116 ((u8 *) &pt1)[8] = 0;
119 if (etags->is_deleted) {
120 memset(&pt1, 0xff, 8);
121 /* clear delete status bit to indicate deleted */
126 memset(&ops, 0, sizeof(ops));
127 ops.mode = MTD_OOB_AUTO;
128 ops.len = (data) ? chunk_bytes : 0;
129 ops.ooblen = dev->param.tags_9bytes ? 9 : 8;
130 ops.datbuf = (u8 *) data;
131 ops.oobbuf = (u8 *) &pt1;
133 retval = mtd->write_oob(mtd, addr, &ops);
135 yaffs_trace(YAFFS_TRACE_MTD,
136 "write_oob failed, chunk %d, mtd error %d",
139 return retval ? YAFFS_FAIL : YAFFS_OK;
142 /* Return with empty ExtendedTags but add ecc_result.
144 static int rettags(struct yaffs_ext_tags *etags, int ecc_result, int retval)
147 memset(etags, 0, sizeof(*etags));
148 etags->ecc_result = ecc_result;
153 /* Read a chunk (page) from NAND.
155 * Caller expects ExtendedTags data to be usable even on error; that is,
156 * all members except ecc_result and block_bad are zeroed.
158 * - Check ECC results for data (if applicable)
159 * - Check for blank/erased block (return empty ExtendedTags if blank)
160 * - Check the packed_tags1 mini-ECC (correct if necessary/possible)
161 * - Convert packed_tags1 to ExtendedTags
162 * - Update ecc_result and block_bad members to refect state.
164 * Returns YAFFS_OK or YAFFS_FAIL.
166 int nandmtd1_read_chunk_tags(struct yaffs_dev *dev,
167 int nand_chunk, u8 *data,
168 struct yaffs_ext_tags *etags)
170 struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
171 int chunk_bytes = dev->data_bytes_per_chunk;
172 loff_t addr = ((loff_t) nand_chunk) * chunk_bytes;
173 int eccres = YAFFS_ECC_RESULT_NO_ERROR;
174 struct mtd_oob_ops ops;
175 struct yaffs_packed_tags1 pt1;
179 memset(&ops, 0, sizeof(ops));
180 ops.mode = MTD_OOB_AUTO;
181 ops.len = (data) ? chunk_bytes : 0;
182 ops.ooblen = dev->param.tags_9bytes ? 9 : 8;
184 ops.oobbuf = (u8 *) &pt1;
186 #if (MTD_VERSION_CODE < MTD_VERSION(2, 6, 20))
187 /* In MTD 2.6.18 to 2.6.19 nand_base.c:nand_do_read_oob() has a bug;
188 * help it out with ops.len = ops.ooblen when ops.datbuf == NULL.
190 ops.len = (ops.datbuf) ? ops.len : ops.ooblen;
192 /* Read page and oob using MTD.
193 * Check status and determine ECC result.
195 retval = mtd->read_oob(mtd, addr, &ops);
197 yaffs_trace(YAFFS_TRACE_MTD,
198 "read_oob failed, chunk %d, mtd error %d",
207 /* MTD's ECC fixed the data */
208 eccres = YAFFS_ECC_RESULT_FIXED;
213 /* MTD's ECC could not fix the data */
214 dev->n_ecc_unfixed++;
217 rettags(etags, YAFFS_ECC_RESULT_UNFIXED, 0);
218 etags->block_bad = (mtd->block_isbad) (mtd, addr);
222 /* Check for a blank/erased chunk.
224 if (yaffs_check_ff((u8 *) &pt1, 8)) {
225 /* when blank, upper layers want ecc_result to be <= NO_ERROR */
226 return rettags(etags, YAFFS_ECC_RESULT_NO_ERROR, YAFFS_OK);
229 if(dev->param.tags_9bytes) {
230 deleted = (hweight8(((u8 *) &pt1)[8]) < 7);
232 /* Read deleted status (bit) then return it to it's non-deleted
233 * state before performing tags mini-ECC check. pt1.deleted is
236 deleted = !pt1.deleted;
240 /* Check the packed tags mini-ECC and correct if necessary/possible.
242 retval = yaffs_check_tags_ecc((struct yaffs_tags *)&pt1);
245 /* no tags error, use MTD result */
248 /* recovered tags-ECC error */
249 dev->n_tags_ecc_fixed++;
250 if (eccres == YAFFS_ECC_RESULT_NO_ERROR)
251 eccres = YAFFS_ECC_RESULT_FIXED;
254 /* unrecovered tags-ECC error */
255 dev->n_tags_ecc_unfixed++;
256 return rettags(etags, YAFFS_ECC_RESULT_UNFIXED, YAFFS_FAIL);
259 /* Unpack the tags to extended form and set ECC result.
260 * [set should_be_ff just to keep yaffs_unpack_tags1 happy]
262 pt1.should_be_ff = 0xffffffff;
263 yaffs_unpack_tags1(etags, &pt1);
264 etags->ecc_result = eccres;
266 /* Set deleted state */
267 etags->is_deleted = deleted;
273 * This is a persistant state.
274 * Use of this function should be rare.
276 * Returns YAFFS_OK or YAFFS_FAIL.
278 int nandmtd1_mark_block_bad(struct yaffs_dev *dev, int block_no)
280 struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
281 int blocksize = dev->param.chunks_per_block * dev->data_bytes_per_chunk;
284 yaffs_trace(YAFFS_TRACE_BAD_BLOCKS, "marking block %d bad", block_no);
286 retval = mtd->block_markbad(mtd, (loff_t) blocksize * block_no);
287 return (retval) ? YAFFS_FAIL : YAFFS_OK;
290 /* Check any MTD prerequists.
292 * Returns YAFFS_OK or YAFFS_FAIL.
294 static int nandmtd1_test_prerequists(struct yaffs_dev *dev, struct mtd_info *mtd)
296 /* 2.6.18 has mtd->ecclayout->oobavail */
297 /* 2.6.21 has mtd->ecclayout->oobavail and mtd->oobavail */
298 int oobavail = mtd->ecclayout->oobavail;
300 if (oobavail < (dev->param.tags_9bytes ? 9 : 8)) {
301 yaffs_trace(YAFFS_TRACE_ERROR,
302 "mtd device has only %d bytes for tags, need %d",
303 oobavail, dev->param.tags_9bytes ? 9 : 8);
309 /* Query for the current state of a specific block.
311 * Examine the tags of the first chunk of the block and return the state:
312 * - YAFFS_BLOCK_STATE_DEAD, the block is marked bad
313 * - YAFFS_BLOCK_STATE_NEEDS_SCAN, the block is in use
314 * - YAFFS_BLOCK_STATE_EMPTY, the block is clean
316 * Always returns YAFFS_OK.
318 int nandmtd1_query_block(struct yaffs_dev *dev, int block_no,
319 enum yaffs_block_state *state_ptr, u32 * seq_ptr)
321 struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
322 int chunk_num = block_no * dev->param.chunks_per_block;
323 loff_t addr = (loff_t) chunk_num * dev->data_bytes_per_chunk;
324 struct yaffs_ext_tags etags;
325 int state = YAFFS_BLOCK_STATE_DEAD;
329 /* We don't yet have a good place to test for MTD config prerequists.
330 * Do it here as we are called during the initial scan.
332 if (nandmtd1_test_prerequists(dev, mtd) != YAFFS_OK)
335 retval = nandmtd1_read_chunk_tags(dev, chunk_num, NULL, &etags);
336 etags.block_bad = (mtd->block_isbad) (mtd, addr);
337 if (etags.block_bad) {
338 yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
339 "block %d is marked bad",
341 state = YAFFS_BLOCK_STATE_DEAD;
342 } else if (etags.ecc_result != YAFFS_ECC_RESULT_NO_ERROR) {
343 /* bad tags, need to look more closely */
344 state = YAFFS_BLOCK_STATE_NEEDS_SCAN;
345 } else if (etags.chunk_used) {
346 state = YAFFS_BLOCK_STATE_NEEDS_SCAN;
347 seqnum = etags.seq_number;
349 state = YAFFS_BLOCK_STATE_EMPTY;
355 /* query always succeeds */
359 #endif /*MTD_VERSION */