--- /dev/null
+/*
+ * 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@aleph1.co.uk>
+ *
+ * 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;
+ yaffs_packed_tags1 pt1;
+ int retval;
+
+ /* we assume that packed_tags1 and struct yaffs_tags are compatible */
+ compile_time_assertion(sizeof(yaffs_packed_tags1) == 12);
+ compile_time_assertion(sizeof(struct yaffs_tags) == 8);
+
+ 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) {
+ T(YAFFS_TRACE_MTD,
+ (TSTR("write_oob failed, chunk %d, mtd error %d"TENDSTR),
+ 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;
+ yaffs_packed_tags1 pt1;
+ int retval;
+ int deleted;
+
+ memset(&ops, 0, sizeof(ops));
+ 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) {
+ T(YAFFS_TRACE_MTD,
+ (TSTR("read_oob failed, chunk %d, mtd error %d"TENDSTR),
+ 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 = (yaffs_count_bits(((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;
+
+ T(YAFFS_TRACE_BAD_BLOCKS,(TSTR("marking block %d bad"TENDSTR), 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 */
+ int oobavail = mtd->ecclayout->oobavail;
+
+ if (oobavail < YTAG1_SIZE) {
+ T(YAFFS_TRACE_ERROR,
+ (TSTR("mtd device has only %d bytes for tags, need %d"TENDSTR),
+ 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) {
+ T(YAFFS_TRACE_BAD_BLOCKS,
+ (TSTR("block %d is marked bad"TENDSTR), 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;
+}
projects / yaffs2.git / blobdiff