+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system.
+ * yaffs_mtdif1.c NAND mtd interface functions for small-page NAND.
+ *
+ * Copyright (C) 2002 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 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_TagsCompatability 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 (useNANDECC is true).
+ */
+
+#include "yportenv.h"
+#include "yaffs_guts.h"
+#include "yaffs_packedtags1.h"
+#include "yaffs_tagscompat.h" // for yaffs_CalcTagsECC
+
+#include "linux/kernel.h"
+#include "linux/version.h"
+#include "linux/types.h"
+#include "linux/mtd/mtd.h"
+
+/* Don't compile this module if we don't have MTD's mtd_oob_ops interface */
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,6,17))
+
+const char *yaffs_mtdif1_c_version = "$Id: yaffs_mtdif1.c,v 1.1 2007-07-18 19:40:38 charles Exp $";
+
+#ifndef CONFIG_YAFFS_9BYTE_TAGS
+# define YTAG1_SIZE 8
+#else
+# define YTAG1_SIZE 9
+#endif
+
+#if 0
+/* Use the following nand_ecclayout with MTD when using
+ * CONFIG_YAFFS_9BYTE_TAGS and the older on-NAND tags layout.
+ * If you have existing Yaffs images and the byte order differs from this,
+ * adjust 'oobfree' to match your existing Yaffs data.
+ *
+ * This nand_ecclayout scatters/gathers to/from the old-yaffs layout with the
+ * pageStatus byte (at NAND spare offset 4) scattered/gathered from/to
+ * the 9th byte.
+ *
+ * Old-style on-NAND format: T0,T1,T2,T3,P,B,T4,T5,E0,E1,E2,T6,T7,E3,E4,E5
+ * We have/need PackedTags1 plus pageStatus: T0,T1,T2,T3,T4,T5,T6,T7,P
+ * where Tn are the tag bytes, En are MTD's ECC bytes, P is the pageStatus
+ * byte and B is the small-page bad-block indicator byte.
+ */
+static struct nand_ecclayout nand_oob_16 = {
+ .eccbytes = 6,
+ .eccpos = { 8, 9, 10, 13, 14, 15 },
+ .oobavail = 9,
+ .oobfree = { { 0, 4 }, { 6, 2 }, { 11, 2 }, { 4, 1 } }
+};
+#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 PackedTags1 form
+ * - Compute mini-ECC for PackedTags1
+ * - Write data and packed tags to NAND.
+ *
+ * Note: Due to the use of the PackedTags1 meta-data which does not include
+ * a full sequence number (as found in the larger PackedTags2 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_WriteChunkWithTagsToNAND(yaffs_Device *dev,
+ int chunkInNAND, const __u8 * data, const yaffs_ExtendedTags * etags)
+{
+ struct mtd_info * mtd = dev->genericDevice;
+ int chunkBytes = dev->nDataBytesPerChunk;
+ loff_t addr = ((loff_t)chunkInNAND) * chunkBytes;
+ struct mtd_oob_ops ops;
+ yaffs_PackedTags1 pt1;
+ int retval;
+
+ /* we assume that PackedTags1 and yaffs_Tags are compatible */
+ compile_time_assertion(sizeof(yaffs_PackedTags1) == 12);
+ compile_time_assertion(sizeof(yaffs_Tags) == 8);
+
+ yaffs_PackTags1(&pt1, etags);
+ yaffs_CalcTagsECC((yaffs_Tags *)&pt1);
+
+ /* When deleting a chunk, the upper layer provides only skeletal
+ * etags, one with chunkDeleted 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->chunkDeleted) {
+ memset(&pt1, 0xff, 8);
+ /* clear delete status bit to indicate deleted */
+ pt1.deleted = 0;
+ }
+#else
+ ((__u8 *)&pt1)[8] = 0xff;
+ if (etags->chunkDeleted) {
+ memset(&pt1, 0xff, 8);
+ /* zero pageStatus byte to indicate deleted */
+ ((__u8 *)&pt1)[8] = 0;
+ }
+#endif
+
+ memset(&ops, 0, sizeof(ops));
+ ops.mode = MTD_OOB_AUTO;
+ ops.len = (data) ? chunkBytes : 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\n",
+ chunkInNAND, retval);
+ }
+ return retval ? YAFFS_FAIL : YAFFS_OK;
+}
+
+/* Return with empty ExtendedTags but add eccResult.
+ */
+static int rettags(yaffs_ExtendedTags * etags, int eccResult, int retval)
+{
+ if (etags) {
+ memset(etags, 0, sizeof(*etags));
+ etags->eccResult = eccResult;
+ }
+ return retval;
+}
+
+/* Read a chunk (page) from NAND.
+ *
+ * Caller expects ExtendedTags data to be usable even on error; that is,
+ * all members except eccResult and blockBad are zeroed.
+ *
+ * - Check ECC results for data (if applicable)
+ * - Check for blank/erased block (return empty ExtendedTags if blank)
+ * - Check the PackedTags1 mini-ECC (correct if necessary/possible)
+ * - Convert PackedTags1 to ExtendedTags
+ * - Update eccResult and blockBad members to refect state.
+ *
+ * Returns YAFFS_OK or YAFFS_FAIL.
+ */
+int nandmtd1_ReadChunkWithTagsFromNAND(yaffs_Device *dev,
+ int chunkInNAND, __u8 * data, yaffs_ExtendedTags * etags)
+{
+ struct mtd_info * mtd = dev->genericDevice;
+ int chunkBytes = dev->nDataBytesPerChunk;
+ loff_t addr = ((loff_t)chunkInNAND) * chunkBytes;
+ int eccres = YAFFS_ECC_RESULT_NO_ERROR;
+ struct mtd_oob_ops ops;
+ yaffs_PackedTags1 pt1;
+ int retval;
+ int deleted;
+
+ memset(&ops, 0, sizeof(ops));
+ ops.mode = MTD_OOB_AUTO;
+ ops.len = (data) ? chunkBytes : 0;
+ ops.ooblen = YTAG1_SIZE;
+ ops.datbuf = data;
+ ops.oobbuf = (__u8 *)&pt1;
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20))
+ /* In MTD 2.6.18 to 2.6.19 nand_base.c:nand_do_read_oob() has a bug;
+ * help it out with ops.len = ops.ooblen when ops.datbuf == NULL.
+ */
+ ops.len = (ops.datbuf) ? ops.len : ops.ooblen;
+#endif
+ /* 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\n",
+ chunkInNAND, retval);
+ }
+
+ switch (retval) {
+ case 0:
+ /* no error */
+ break;
+
+ case -EUCLEAN:
+ /* MTD's ECC fixed the data */
+ eccres = YAFFS_ECC_RESULT_FIXED;
+ dev->eccFixed++;
+ break;
+
+ case -EBADMSG:
+ /* MTD's ECC could not fix the data */
+ dev->eccUnfixed++;
+ /* fall into... */
+ default:
+ rettags(etags, YAFFS_ECC_RESULT_UNFIXED, 0);
+ etags->blockBad = (mtd->block_isbad)(mtd, addr);
+ return YAFFS_FAIL;
+ }
+
+ /* Check for a blank/erased chunk.
+ */
+ if (yaffs_CheckFF((__u8 *)&pt1, 8)) {
+ /* when blank, upper layers want eccResult 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
+ (void) deleted; /* not used */
+#endif
+
+ /* Check the packed tags mini-ECC and correct if necessary/possible.
+ */
+ retval = yaffs_CheckECCOnTags((yaffs_Tags *)&pt1);
+ switch (retval) {
+ case 0:
+ /* no tags error, use MTD result */
+ break;
+ case 1:
+ /* recovered tags-ECC error */
+ dev->tagsEccFixed++;
+ eccres = YAFFS_ECC_RESULT_FIXED;
+ break;
+ default:
+ /* unrecovered tags-ECC error */
+ dev->tagsEccUnfixed++;
+ return rettags(etags, YAFFS_ECC_RESULT_UNFIXED, YAFFS_FAIL);
+ }
+
+ /* Unpack the tags to extended form and set ECC result.
+ * [set shouldBeFF just to keep yaffs_UnpackTags1 happy]
+ */
+ pt1.shouldBeFF = 0xFFFFFFFF;
+ yaffs_UnpackTags1(etags, &pt1);
+ etags->eccResult = eccres;
+
+ /* Set deleted state.
+ */
+#ifndef CONFIG_YAFFS_9BYTE_TAGS
+ etags->chunkDeleted = deleted;
+#else
+ etags->chunkDeleted = (yaffs_CountBits(((__u8 *)&pt1)[8]) < 7);
+#endif
+ 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_MarkNANDBlockBad(struct yaffs_DeviceStruct *dev, int blockNo)
+{
+ struct mtd_info * mtd = dev->genericDevice;
+ int blocksize = dev->nChunksPerBlock * dev->nDataBytesPerChunk;
+ int retval;
+
+ yaffs_trace(YAFFS_TRACE_BAD_BLOCKS, "marking block %d bad", blockNo);
+
+ retval = mtd->block_markbad(mtd, (loff_t)blocksize * blockNo);
+ return (retval) ? YAFFS_FAIL : YAFFS_OK;
+}
+
+/* Check any MTD prerequists.
+ *
+ * Returns YAFFS_OK or YAFFS_FAIL.
+ */
+static int nandmtd1_TestPrerequists(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) {
+ 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_QueryNANDBlock(struct yaffs_DeviceStruct *dev, int blockNo,
+ yaffs_BlockState * pState, int *pSequenceNumber)
+{
+ struct mtd_info * mtd = dev->genericDevice;
+ int chunkNo = blockNo * dev->nChunksPerBlock;
+ yaffs_ExtendedTags 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_TestPrerequists(mtd) != YAFFS_OK) {
+ return YAFFS_FAIL;
+ }
+
+ retval = nandmtd1_ReadChunkWithTagsFromNAND(dev, chunkNo, NULL, &etags);
+ if (etags.blockBad) {
+ yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
+ "block %d is marked bad", blockNo);
+ state = YAFFS_BLOCK_STATE_DEAD;
+ }
+ else if (etags.chunkUsed) {
+ state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
+ seqnum = etags.sequenceNumber;
+ }
+ else {
+ state = YAFFS_BLOCK_STATE_EMPTY;
+ }
+
+ *pState = state;
+ *pSequenceNumber = seqnum;
+
+ /* query always succeeds */
+ return YAFFS_OK;
+}
+
+#endif /*KERNEL_VERSION*/
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