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 #if (LINUX_VERSION_CODE < KERNEL_VERSION(3, 2, 0))
40 #define MTD_OPS_AUTO_OOB MTD_OOB_AUTO
44 /* Don't compile this module if we don't have MTD's mtd_oob_ops interface */
45 #if (MTD_VERSION_CODE > MTD_VERSION(2, 6, 17))
49 /* Use the following nand_ecclayout with MTD when using
50 * 9 byte tags and the older on-NAND tags layout.
51 * If you have existing Yaffs images and the byte order differs from this,
52 * adjust 'oobfree' to match your existing Yaffs data.
54 * This nand_ecclayout scatters/gathers to/from the old-yaffs layout with the
55 * page_status byte (at NAND spare offset 4) scattered/gathered from/to
58 * Old-style on-NAND format: T0,T1,T2,T3,P,B,T4,T5,E0,E1,E2,T6,T7,E3,E4,E5
59 * We have/need packed_tags1 plus page_status: T0,T1,T2,T3,T4,T5,T6,T7,P
60 * where Tn are the tag bytes, En are MTD's ECC bytes, P is the page_status
61 * byte and B is the small-page bad-block indicator byte.
63 static struct nand_ecclayout nand_oob_16 = {
65 .eccpos = {8, 9, 10, 13, 14, 15},
67 .oobfree = {{0, 4}, {6, 2}, {11, 2}, {4, 1} }
71 /* Write a chunk (page) of data to NAND.
73 * Caller always provides ExtendedTags data which are converted to a more
74 * compact (packed) form for storage in NAND. A mini-ECC runs over the
75 * contents of the tags meta-data; used to valid the tags when read.
77 * - Pack ExtendedTags to packed_tags1 form
78 * - Compute mini-ECC for packed_tags1
79 * - Write data and packed tags to NAND.
81 * Note: Due to the use of the packed_tags1 meta-data which does not include
82 * a full sequence number (as found in the larger packed_tags2 form) it is
83 * necessary for Yaffs to re-write a chunk/page (just once) to mark it as
84 * discarded and dirty. This is not ideal: newer NAND parts are supposed
85 * to be written just once. When Yaffs performs this operation, this
86 * function is called with a NULL data pointer -- calling MTD write_oob
87 * without data is valid usage (2.6.17).
89 * Any underlying MTD error results in YAFFS_FAIL.
90 * Returns YAFFS_OK or YAFFS_FAIL.
92 int nandmtd1_write_chunk_tags(struct yaffs_dev *dev,
93 int nand_chunk, const u8 *data,
94 const struct yaffs_ext_tags *etags)
96 struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
97 int chunk_bytes = dev->data_bytes_per_chunk;
98 loff_t addr = ((loff_t) nand_chunk) * chunk_bytes;
99 struct mtd_oob_ops ops;
100 struct yaffs_packed_tags1 pt1;
103 /* we assume that packed_tags1 and struct yaffs_tags are compatible */
104 compile_time_assertion(sizeof(struct yaffs_packed_tags1) == 12);
105 compile_time_assertion(sizeof(struct yaffs_tags) == 8);
107 yaffs_pack_tags1(&pt1, etags);
108 yaffs_calc_tags_ecc((struct yaffs_tags *)&pt1);
110 /* When deleting a chunk, the upper layer provides only skeletal
111 * etags, one with is_deleted set. However, we need to update the
112 * tags, not erase them completely. So we use the NAND write property
113 * that only zeroed-bits stick and set tag bytes to all-ones and
114 * zero just the (not) deleted bit.
116 if(dev->param.tags_9bytes) {
117 ((u8 *) &pt1)[8] = 0xff;
118 if (etags->is_deleted) {
119 memset(&pt1, 0xff, 8);
120 /* zero page_status byte to indicate deleted */
121 ((u8 *) &pt1)[8] = 0;
124 if (etags->is_deleted) {
125 memset(&pt1, 0xff, 8);
126 /* clear delete status bit to indicate deleted */
131 memset(&ops, 0, sizeof(ops));
132 ops.mode = MTD_OPS_AUTO_OOB;
133 ops.len = (data) ? chunk_bytes : 0;
134 ops.ooblen = dev->param.tags_9bytes ? 9 : 8;
135 ops.datbuf = (u8 *) data;
136 ops.oobbuf = (u8 *) &pt1;
138 retval = mtd->write_oob(mtd, addr, &ops);
140 yaffs_trace(YAFFS_TRACE_MTD,
141 "write_oob failed, chunk %d, mtd error %d",
144 return retval ? YAFFS_FAIL : YAFFS_OK;
147 /* Return with empty ExtendedTags but add ecc_result.
149 static int rettags(struct yaffs_ext_tags *etags, int ecc_result, int retval)
152 memset(etags, 0, sizeof(*etags));
153 etags->ecc_result = ecc_result;
158 /* Read a chunk (page) from NAND.
160 * Caller expects ExtendedTags data to be usable even on error; that is,
161 * all members except ecc_result and block_bad are zeroed.
163 * - Check ECC results for data (if applicable)
164 * - Check for blank/erased block (return empty ExtendedTags if blank)
165 * - Check the packed_tags1 mini-ECC (correct if necessary/possible)
166 * - Convert packed_tags1 to ExtendedTags
167 * - Update ecc_result and block_bad members to refect state.
169 * Returns YAFFS_OK or YAFFS_FAIL.
171 int nandmtd1_read_chunk_tags(struct yaffs_dev *dev,
172 int nand_chunk, u8 *data,
173 struct yaffs_ext_tags *etags)
175 struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
176 int chunk_bytes = dev->data_bytes_per_chunk;
177 loff_t addr = ((loff_t) nand_chunk) * chunk_bytes;
178 int eccres = YAFFS_ECC_RESULT_NO_ERROR;
179 struct mtd_oob_ops ops;
180 struct yaffs_packed_tags1 pt1;
184 memset(&ops, 0, sizeof(ops));
185 ops.mode = MTD_OPS_AUTO_OOB;
186 ops.len = (data) ? chunk_bytes : 0;
187 ops.ooblen = dev->param.tags_9bytes ? 9 : 8;
189 ops.oobbuf = (u8 *) &pt1;
191 #if (MTD_VERSION_CODE < MTD_VERSION(2, 6, 20))
192 /* In MTD 2.6.18 to 2.6.19 nand_base.c:nand_do_read_oob() has a bug;
193 * help it out with ops.len = ops.ooblen when ops.datbuf == NULL.
195 ops.len = (ops.datbuf) ? ops.len : ops.ooblen;
197 /* Read page and oob using MTD.
198 * Check status and determine ECC result.
200 retval = mtd->read_oob(mtd, addr, &ops);
202 yaffs_trace(YAFFS_TRACE_MTD,
203 "read_oob failed, chunk %d, mtd error %d",
212 /* MTD's ECC fixed the data */
213 eccres = YAFFS_ECC_RESULT_FIXED;
218 /* MTD's ECC could not fix the data */
219 dev->n_ecc_unfixed++;
222 rettags(etags, YAFFS_ECC_RESULT_UNFIXED, 0);
223 etags->block_bad = (mtd->block_isbad) (mtd, addr);
227 /* Check for a blank/erased chunk.
229 if (yaffs_check_ff((u8 *) &pt1, 8)) {
230 /* when blank, upper layers want ecc_result to be <= NO_ERROR */
231 return rettags(etags, YAFFS_ECC_RESULT_NO_ERROR, YAFFS_OK);
234 if(dev->param.tags_9bytes) {
235 deleted = (hweight8(((u8 *) &pt1)[8]) < 7);
237 /* Read deleted status (bit) then return it to it's non-deleted
238 * state before performing tags mini-ECC check. pt1.deleted is
241 deleted = !pt1.deleted;
245 /* Check the packed tags mini-ECC and correct if necessary/possible.
247 retval = yaffs_check_tags_ecc((struct yaffs_tags *)&pt1);
250 /* no tags error, use MTD result */
253 /* recovered tags-ECC error */
254 dev->n_tags_ecc_fixed++;
255 if (eccres == YAFFS_ECC_RESULT_NO_ERROR)
256 eccres = YAFFS_ECC_RESULT_FIXED;
259 /* unrecovered tags-ECC error */
260 dev->n_tags_ecc_unfixed++;
261 return rettags(etags, YAFFS_ECC_RESULT_UNFIXED, YAFFS_FAIL);
264 /* Unpack the tags to extended form and set ECC result.
265 * [set should_be_ff just to keep yaffs_unpack_tags1 happy]
267 pt1.should_be_ff = 0xffffffff;
268 yaffs_unpack_tags1(etags, &pt1);
269 etags->ecc_result = eccres;
271 /* Set deleted state */
272 etags->is_deleted = deleted;
278 * This is a persistant state.
279 * Use of this function should be rare.
281 * Returns YAFFS_OK or YAFFS_FAIL.
283 int nandmtd1_mark_block_bad(struct yaffs_dev *dev, int block_no)
285 struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
286 int blocksize = dev->param.chunks_per_block * dev->data_bytes_per_chunk;
289 yaffs_trace(YAFFS_TRACE_BAD_BLOCKS, "marking block %d bad", block_no);
291 retval = mtd->block_markbad(mtd, (loff_t) blocksize * block_no);
292 return (retval) ? YAFFS_FAIL : YAFFS_OK;
295 /* Check any MTD prerequists.
297 * Returns YAFFS_OK or YAFFS_FAIL.
299 static int nandmtd1_test_prerequists(struct yaffs_dev *dev, struct mtd_info *mtd)
301 /* 2.6.18 has mtd->ecclayout->oobavail */
302 /* 2.6.21 has mtd->ecclayout->oobavail and mtd->oobavail */
303 int oobavail = mtd->ecclayout->oobavail;
305 if (oobavail < (dev->param.tags_9bytes ? 9 : 8)) {
306 yaffs_trace(YAFFS_TRACE_ERROR,
307 "mtd device has only %d bytes for tags, need %d",
308 oobavail, dev->param.tags_9bytes ? 9 : 8);
314 /* Query for the current state of a specific block.
316 * Examine the tags of the first chunk of the block and return the state:
317 * - YAFFS_BLOCK_STATE_DEAD, the block is marked bad
318 * - YAFFS_BLOCK_STATE_NEEDS_SCAN, the block is in use
319 * - YAFFS_BLOCK_STATE_EMPTY, the block is clean
321 * Always returns YAFFS_OK.
323 int nandmtd1_query_block(struct yaffs_dev *dev, int block_no,
324 enum yaffs_block_state *state_ptr, u32 * seq_ptr)
326 struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
327 int chunk_num = block_no * dev->param.chunks_per_block;
328 loff_t addr = (loff_t) chunk_num * dev->data_bytes_per_chunk;
329 struct yaffs_ext_tags etags;
330 int state = YAFFS_BLOCK_STATE_DEAD;
334 /* We don't yet have a good place to test for MTD config prerequists.
335 * Do it here as we are called during the initial scan.
337 if (nandmtd1_test_prerequists(dev, mtd) != YAFFS_OK)
340 retval = nandmtd1_read_chunk_tags(dev, chunk_num, NULL, &etags);
341 etags.block_bad = (mtd->block_isbad) (mtd, addr);
342 if (etags.block_bad) {
343 yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
344 "block %d is marked bad",
346 state = YAFFS_BLOCK_STATE_DEAD;
347 } else if (etags.ecc_result != YAFFS_ECC_RESULT_NO_ERROR) {
348 /* bad tags, need to look more closely */
349 state = YAFFS_BLOCK_STATE_NEEDS_SCAN;
350 } else if (etags.chunk_used) {
351 state = YAFFS_BLOCK_STATE_NEEDS_SCAN;
352 seqnum = etags.seq_number;
354 state = YAFFS_BLOCK_STATE_EMPTY;
360 /* query always succeeds */
364 #endif /*MTD_VERSION */