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"
33 #include "linux/kernel.h"
34 #include "linux/version.h"
35 #include "linux/types.h"
36 #include "linux/mtd/mtd.h"
38 /* Write a chunk (page) of data to NAND.
40 * Caller always provides ExtendedTags data which are converted to a more
41 * compact (packed) form for storage in NAND. A mini-ECC runs over the
42 * contents of the tags meta-data; used to valid the tags when read.
44 * - Pack ExtendedTags to packed_tags1 form
45 * - Compute mini-ECC for packed_tags1
46 * - Write data and packed tags to NAND.
48 * Note: Due to the use of the packed_tags1 meta-data which does not include
49 * a full sequence number (as found in the larger packed_tags2 form) it is
50 * necessary for Yaffs to re-write a chunk/page (just once) to mark it as
51 * discarded and dirty. This is not ideal: newer NAND parts are supposed
52 * to be written just once. When Yaffs performs this operation, this
53 * function is called with a NULL data pointer -- calling MTD write_oob
54 * without data is valid usage (2.6.17).
56 * Any underlying MTD error results in YAFFS_FAIL.
57 * Returns YAFFS_OK or YAFFS_FAIL.
59 int nandmtd1_write_chunk_tags(struct yaffs_dev *dev,
60 int nand_chunk, const u8 *data,
61 const struct yaffs_ext_tags *etags)
63 struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
64 int chunk_bytes = dev->data_bytes_per_chunk;
65 loff_t addr = ((loff_t) nand_chunk) * chunk_bytes;
66 struct mtd_oob_ops ops;
67 struct yaffs_packed_tags1 pt1;
70 /* we assume that packed_tags1 and struct yaffs_tags are compatible */
71 compile_time_assertion(sizeof(struct yaffs_packed_tags1) == 12);
72 compile_time_assertion(sizeof(struct yaffs_tags) == 8);
74 yaffs_pack_tags1(&pt1, etags);
75 yaffs_calc_tags_ecc((struct yaffs_tags *)&pt1);
77 /* When deleting a chunk, the upper layer provides only skeletal
78 * etags, one with is_deleted set. However, we need to update the
79 * tags, not erase them completely. So we use the NAND write property
80 * that only zeroed-bits stick and set tag bytes to all-ones and
81 * zero just the (not) deleted bit.
84 if(dev->param.tags_9bytes) {
85 ((u8 *) &pt1)[8] = 0xff;
86 if (etags->is_deleted) {
87 memset(&pt1, 0xff, 8);
88 /* zero page_status byte to indicate deleted */
92 if (etags->is_deleted) {
93 memset(&pt1, 0xff, 8);
94 /* clear delete status bit to indicate deleted */
99 memset(&ops, 0, sizeof(ops));
100 ops.mode = MTD_OPS_AUTO_OOB;
101 ops.len = (data) ? chunk_bytes : 0;
102 ops.ooblen = dev->param.tags_9bytes ? 9 : 8;
103 ops.datbuf = (u8 *) data;
104 ops.oobbuf = (u8 *) &pt1;
106 retval = mtd->write_oob(mtd, addr, &ops);
108 yaffs_trace(YAFFS_TRACE_MTD,
109 "write_oob failed, chunk %d, mtd error %d",
112 return retval ? YAFFS_FAIL : YAFFS_OK;
115 /* Return with empty ExtendedTags but add ecc_result.
117 static int rettags(struct yaffs_ext_tags *etags, int ecc_result, int retval)
120 memset(etags, 0, sizeof(*etags));
121 etags->ecc_result = ecc_result;
126 /* Read a chunk (page) from NAND.
128 * Caller expects ExtendedTags data to be usable even on error; that is,
129 * all members except ecc_result and block_bad are zeroed.
131 * - Check ECC results for data (if applicable)
132 * - Check for blank/erased block (return empty ExtendedTags if blank)
133 * - Check the packed_tags1 mini-ECC (correct if necessary/possible)
134 * - Convert packed_tags1 to ExtendedTags
135 * - Update ecc_result and block_bad members to refect state.
137 * Returns YAFFS_OK or YAFFS_FAIL.
139 int nandmtd1_read_chunk_tags(struct yaffs_dev *dev,
140 int nand_chunk, u8 *data,
141 struct yaffs_ext_tags *etags)
143 struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
144 int chunk_bytes = dev->data_bytes_per_chunk;
145 loff_t addr = ((loff_t) nand_chunk) * chunk_bytes;
146 int eccres = YAFFS_ECC_RESULT_NO_ERROR;
147 struct mtd_oob_ops ops;
148 struct yaffs_packed_tags1 pt1;
152 memset(&ops, 0, sizeof(ops));
153 ops.mode = MTD_OPS_AUTO_OOB;
154 ops.len = (data) ? chunk_bytes : 0;
155 ops.ooblen = dev->param.tags_9bytes ? 9 : 8;
157 ops.oobbuf = (u8 *) &pt1;
159 /* Read page and oob using MTD.
160 * Check status and determine ECC result.
162 retval = mtd->read_oob(mtd, addr, &ops);
164 yaffs_trace(YAFFS_TRACE_MTD,
165 "read_oob failed, chunk %d, mtd error %d",
175 /* MTD's ECC fixed the data */
176 eccres = YAFFS_ECC_RESULT_FIXED;
181 /* MTD's ECC could not fix the data */
182 dev->n_ecc_unfixed++;
185 rettags(etags, YAFFS_ECC_RESULT_UNFIXED, 0);
186 etags->block_bad = (mtd->block_isbad) (mtd, addr);
190 /* Check for a blank/erased chunk.
192 if (yaffs_check_ff((u8 *) &pt1, 8)) {
193 /* when blank, upper layers want ecc_result to be <= NO_ERROR */
194 return rettags(etags, YAFFS_ECC_RESULT_NO_ERROR, YAFFS_OK);
196 #ifndef CONFIG_YAFFS_9BYTE_TAGS
197 /* Read deleted status (bit) then return it to it's non-deleted
198 * state before performing tags mini-ECC check. pt1.deleted is
201 deleted = !pt1.deleted;
204 deleted = (hweight8(((u8 *) &pt1)[8]) < 7);
207 /* Check the packed tags mini-ECC and correct if necessary/possible.
209 retval = yaffs_check_tags_ecc((struct yaffs_tags *)&pt1);
212 /* no tags error, use MTD result */
215 /* recovered tags-ECC error */
216 dev->n_tags_ecc_fixed++;
217 if (eccres == YAFFS_ECC_RESULT_NO_ERROR)
218 eccres = YAFFS_ECC_RESULT_FIXED;
221 /* unrecovered tags-ECC error */
222 dev->n_tags_ecc_unfixed++;
223 return rettags(etags, YAFFS_ECC_RESULT_UNFIXED, YAFFS_FAIL);
226 /* Unpack the tags to extended form and set ECC result.
227 * [set should_be_ff just to keep yaffs_unpack_tags1 happy]
229 pt1.should_be_ff = 0xffffffff;
230 yaffs_unpack_tags1(etags, &pt1);
231 etags->ecc_result = eccres;
233 /* Set deleted state */
234 etags->is_deleted = deleted;
240 * This is a persistant state.
241 * Use of this function should be rare.
243 * Returns YAFFS_OK or YAFFS_FAIL.
245 int nandmtd1_mark_block_bad(struct yaffs_dev *dev, int block_no)
247 struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
248 int blocksize = dev->param.chunks_per_block * dev->data_bytes_per_chunk;
251 yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
252 "marking block %d bad", block_no);
254 retval = mtd->block_markbad(mtd, (loff_t) blocksize * block_no);
255 return (retval) ? YAFFS_FAIL : YAFFS_OK;
258 /* Check any MTD prerequists.
260 * Returns YAFFS_OK or YAFFS_FAIL.
262 static int nandmtd1_test_prerequists(struct yaffs_dev *dev, struct mtd_info *mtd)
264 /* 2.6.18 has mtd->ecclayout->oobavail */
265 /* 2.6.21 has mtd->ecclayout->oobavail and mtd->oobavail */
266 int oobavail = mtd->ecclayout->oobavail;
268 if (oobavail < (dev->param.tags_9bytes ? 9 : 8)) {
269 yaffs_trace(YAFFS_TRACE_ERROR,
270 "mtd device has only %d bytes for tags, need %d",
271 oobavail, (dev->param.tags_9bytes ? 9 : 8));
277 /* Query for the current state of a specific block.
279 * Examine the tags of the first chunk of the block and return the state:
280 * - YAFFS_BLOCK_STATE_DEAD, the block is marked bad
281 * - YAFFS_BLOCK_STATE_NEEDS_SCAN, the block is in use
282 * - YAFFS_BLOCK_STATE_EMPTY, the block is clean
284 * Always returns YAFFS_OK.
286 int nandmtd1_query_block(struct yaffs_dev *dev, int block_no,
287 enum yaffs_block_state *state_ptr, u32 * seq_ptr)
289 struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
290 int chunk_num = block_no * dev->param.chunks_per_block;
291 loff_t addr = (loff_t) chunk_num * dev->data_bytes_per_chunk;
292 struct yaffs_ext_tags etags;
293 int state = YAFFS_BLOCK_STATE_DEAD;
297 /* We don't yet have a good place to test for MTD config prerequists.
298 * Do it here as we are called during the initial scan.
300 if (nandmtd1_test_prerequists(dev, mtd) != YAFFS_OK)
303 retval = nandmtd1_read_chunk_tags(dev, chunk_num, NULL, &etags);
304 etags.block_bad = (mtd->block_isbad) (mtd, addr);
305 if (etags.block_bad) {
306 yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
307 "block %d is marked bad", block_no);
308 state = YAFFS_BLOCK_STATE_DEAD;
309 } else if (etags.ecc_result != YAFFS_ECC_RESULT_NO_ERROR) {
310 /* bad tags, need to look more closely */
311 state = YAFFS_BLOCK_STATE_NEEDS_SCAN;
312 } else if (etags.chunk_used) {
313 state = YAFFS_BLOCK_STATE_NEEDS_SCAN;
314 seqnum = etags.seq_number;
316 state = YAFFS_BLOCK_STATE_EMPTY;
322 /* query always succeeds */