1 files changed, 536 insertions, 0 deletions
diff --git a/drivers/mtd/nand/core.c b/drivers/mtd/nand/core.c
new file mode 100644
index 000000000000..3e76d127715f
--- /dev/null
+++ b/drivers/mtd/nand/core.c
@@ -0,0 +1,536 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2017 Free Electrons
+ *
+ * Authors:
+ *	Boris Brezillon <boris.brezillon@free-electrons.com>
+ *	Peter Pan <peterpandong@micron.com>
+ */
+
+#define pr_fmt(fmt)	"nand: " fmt
+
+#include <linux/module.h>
+#include <linux/mtd/nand.h>
+
+/**
+ * nand_check_erased_buf - check if a buffer contains (almost) only 0xff data
+ * @buf: buffer to test
+ * @len: buffer length
+ * @bitflips_threshold: maximum number of bitflips
+ *
+ * Check if a buffer contains only 0xff, which means the underlying region
+ * has been erased and is ready to be programmed.
+ * The bitflips_threshold specify the maximum number of bitflips before
+ * considering the region is not erased.
+ * Note: The logic of this function has been extracted from the memweight
+ * implementation, except that nand_check_erased_buf function exit before
+ * testing the whole buffer if the number of bitflips exceed the
+ * bitflips_threshold value.
+ *
+ * Returns a positive number of bitflips less than or equal to
+ * bitflips_threshold, or -ERROR_CODE for bitflips in excess of the
+ * threshold.
+ */
+static int nand_check_erased_buf(void *buf, int len, int bitflips_threshold)
+{
+	const unsigned char *bitmap = buf;
+	int bitflips = 0;
+	int weight;
+
+	for (; len && ((uintptr_t)bitmap) % sizeof(long);
+	     len--, bitmap++) {
+		weight = hweight8(*bitmap);
+		bitflips += BITS_PER_BYTE - weight;
+		if (unlikely(bitflips > bitflips_threshold))
+			return -EBADMSG;
+	}
+
+	for (; len >= sizeof(long);
+	     len -= sizeof(long), bitmap += sizeof(long)) {
+		unsigned long d = *((unsigned long *)bitmap);
+		if (d == ~0UL)
+			continue;
+		weight = hweight_long(d);
+		bitflips += BITS_PER_LONG - weight;
+		if (unlikely(bitflips > bitflips_threshold))
+			return -EBADMSG;
+	}
+
+	for (; len > 0; len--, bitmap++) {
+		weight = hweight8(*bitmap);
+		bitflips += BITS_PER_BYTE - weight;
+		if (unlikely(bitflips > bitflips_threshold))
+			return -EBADMSG;
+	}
+
+	return bitflips;
+}
+
+/**
+ * nand_check_erased_ecc_chunk - check if an ECC chunk contains (almost) only
+ *				 0xff data
+ * @data: data buffer to test
+ * @datalen: data length
+ * @ecc: ECC buffer
+ * @ecclen: ECC length
+ * @extraoob: extra OOB buffer
+ * @extraooblen: extra OOB length
+ * @bitflips_threshold: maximum number of bitflips
+ *
+ * Check if a data buffer and its associated ECC and OOB data contains only
+ * 0xff pattern, which means the underlying region has been erased and is
+ * ready to be programmed.
+ * The bitflips_threshold specify the maximum number of bitflips before
+ * considering the region as not erased.
+ *
+ * Note:
+ * 1/ ECC algorithms are working on pre-defined block sizes which are usually
+ *    different from the NAND page size. When fixing bitflips, ECC engines will
+ *    report the number of errors per chunk, and the NAND core infrastructure
+ *    expect you to return the maximum number of bitflips for the whole page.
+ *    This is why you should always use this function on a single chunk and
+ *    not on the whole page. After checking each chunk you should update your
+ *    max_bitflips value accordingly.
+ * 2/ When checking for bitflips in erased pages you should not only check
+ *    the payload data but also their associated ECC data, because a user might
+ *    have programmed almost all bits to 1 but a few. In this case, we
+ *    shouldn't consider the chunk as erased, and checking ECC bytes prevent
+ *    this case.
+ * 3/ The extraoob argument is optional, and should be used if some of your OOB
+ *    data are protected by the ECC engine.
+ *    It could also be used if you support subpages and want to attach some
+ *    extra OOB data to an ECC chunk.
+ *
+ * Returns a positive number of bitflips less than or equal to
+ * bitflips_threshold, or -ERROR_CODE for bitflips in excess of the
+ * threshold. In case of success, the passed buffers are filled with 0xff.
+ */
+int nand_check_erased_ecc_chunk(void *data, int datalen,
+				void *ecc, int ecclen,
+				void *extraoob, int extraooblen,
+				int bitflips_threshold)
+{
+	int data_bitflips = 0, ecc_bitflips = 0, extraoob_bitflips = 0;
+
+	data_bitflips = nand_check_erased_buf(data, datalen,
+					      bitflips_threshold);
+	if (data_bitflips < 0)
+		return data_bitflips;
+
+	bitflips_threshold -= data_bitflips;
+
+	ecc_bitflips = nand_check_erased_buf(ecc, ecclen, bitflips_threshold);
+	if (ecc_bitflips < 0)
+		return ecc_bitflips;
+
+	bitflips_threshold -= ecc_bitflips;
+
+	extraoob_bitflips = nand_check_erased_buf(extraoob, extraooblen,
+						  bitflips_threshold);
+	if (extraoob_bitflips < 0)
+		return extraoob_bitflips;
+
+	if (data_bitflips)
+		memset(data, 0xff, datalen);
+
+	if (ecc_bitflips)
+		memset(ecc, 0xff, ecclen);
+
+	if (extraoob_bitflips)
+		memset(extraoob, 0xff, extraooblen);
+
+	return data_bitflips + ecc_bitflips + extraoob_bitflips;
+}
+EXPORT_SYMBOL(nand_check_erased_ecc_chunk);
+
+/**
+ * nanddev_isbad() - Check if a block is bad
+ * @nand: NAND device
+ * @pos: position pointing to the block we want to check
+ *
+ * Return: true if the block is bad, false otherwise.
+ */
+bool nanddev_isbad(struct nand_device *nand, const struct nand_pos *pos)
+{
+	if (mtd_check_expert_analysis_mode())
+		return false;
+
+	if (nanddev_bbt_is_initialized(nand)) {
+		unsigned int entry;
+		int status;
+
+		entry = nanddev_bbt_pos_to_entry(nand, pos);
+		status = nanddev_bbt_get_block_status(nand, entry);
+		/* Lazy block status retrieval */
+		if (status == NAND_BBT_BLOCK_STATUS_UNKNOWN) {
+			if (nand->ops->isbad(nand, pos))
+				status = NAND_BBT_BLOCK_FACTORY_BAD;
+			else
+				status = NAND_BBT_BLOCK_GOOD;
+
+			nanddev_bbt_set_block_status(nand, entry, status);
+		}
+
+		if (status == NAND_BBT_BLOCK_WORN ||
+		    status == NAND_BBT_BLOCK_FACTORY_BAD)
+			return true;
+
+		return false;
+	}
+
+	return nand->ops->isbad(nand, pos);
+}
+EXPORT_SYMBOL_GPL(nanddev_isbad);
+
+/**
+ * nanddev_markbad() - Mark a block as bad
+ * @nand: NAND device
+ * @pos: position of the block to mark bad
+ *
+ * Mark a block bad. This function is updating the BBT if available and
+ * calls the low-level markbad hook (nand->ops->markbad()).
+ *
+ * Return: 0 in case of success, a negative error code otherwise.
+ */
+int nanddev_markbad(struct nand_device *nand, const struct nand_pos *pos)
+{
+	struct mtd_info *mtd = nanddev_to_mtd(nand);
+	unsigned int entry;
+	int ret = 0;
+
+	if (nanddev_isbad(nand, pos))
+		return 0;
+
+	ret = nand->ops->markbad(nand, pos);
+	if (ret)
+		pr_warn("failed to write BBM to block @%llx (err = %d)\n",
+			nanddev_pos_to_offs(nand, pos), ret);
+
+	if (!nanddev_bbt_is_initialized(nand))
+		goto out;
+
+	entry = nanddev_bbt_pos_to_entry(nand, pos);
+	ret = nanddev_bbt_set_block_status(nand, entry, NAND_BBT_BLOCK_WORN);
+	if (ret)
+		goto out;
+
+	ret = nanddev_bbt_update(nand);
+
+out:
+	if (!ret)
+		mtd->ecc_stats.badblocks++;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nanddev_markbad);
+
+/**
+ * nanddev_isreserved() - Check whether an eraseblock is reserved or not
+ * @nand: NAND device
+ * @pos: NAND position to test
+ *
+ * Checks whether the eraseblock pointed by @pos is reserved or not.
+ *
+ * Return: true if the eraseblock is reserved, false otherwise.
+ */
+bool nanddev_isreserved(struct nand_device *nand, const struct nand_pos *pos)
+{
+	unsigned int entry;
+	int status;
+
+	if (!nanddev_bbt_is_initialized(nand))
+		return false;
+
+	/* Return info from the table */
+	entry = nanddev_bbt_pos_to_entry(nand, pos);
+	status = nanddev_bbt_get_block_status(nand, entry);
+	return status == NAND_BBT_BLOCK_RESERVED;
+}
+EXPORT_SYMBOL_GPL(nanddev_isreserved);
+
+/**
+ * nanddev_erase() - Erase a NAND portion
+ * @nand: NAND device
+ * @pos: position of the block to erase
+ *
+ * Erases the block if it's not bad.
+ *
+ * Return: 0 in case of success, a negative error code otherwise.
+ */
+static int nanddev_erase(struct nand_device *nand, const struct nand_pos *pos)
+{
+	if (nanddev_isbad(nand, pos) || nanddev_isreserved(nand, pos)) {
+		pr_warn("attempt to erase a bad/reserved block @%llx\n",
+			nanddev_pos_to_offs(nand, pos));
+		return -EIO;
+	}
+
+	return nand->ops->erase(nand, pos);
+}
+
+/**
+ * nanddev_mtd_erase() - Generic mtd->_erase() implementation for NAND devices
+ * @mtd: MTD device
+ * @einfo: erase request
+ *
+ * This is a simple mtd->_erase() implementation iterating over all blocks
+ * concerned by @einfo and calling nand->ops->erase() on each of them.
+ *
+ * Note that mtd->_erase should not be directly assigned to this helper,
+ * because there's no locking here. NAND specialized layers should instead
+ * implement there own wrapper around nanddev_mtd_erase() taking the
+ * appropriate lock before calling nanddev_mtd_erase().
+ *
+ * Return: 0 in case of success, a negative error code otherwise.
+ */
+int nanddev_mtd_erase(struct mtd_info *mtd, struct erase_info *einfo)
+{
+	struct nand_device *nand = mtd_to_nanddev(mtd);
+	struct nand_pos pos, last;
+	int ret;
+
+	nanddev_offs_to_pos(nand, einfo->addr, &pos);
+	nanddev_offs_to_pos(nand, einfo->addr + einfo->len - 1, &last);
+	while (nanddev_pos_cmp(&pos, &last) <= 0) {
+		ret = nanddev_erase(nand, &pos);
+		if (ret) {
+			einfo->fail_addr = nanddev_pos_to_offs(nand, &pos);
+
+			return ret;
+		}
+
+		nanddev_pos_next_eraseblock(nand, &pos);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nanddev_mtd_erase);
+
+/**
+ * nanddev_mtd_max_bad_blocks() - Get the maximum number of bad eraseblock on
+ *				  a specific region of the NAND device
+ * @mtd: MTD device
+ * @offs: offset of the NAND region
+ * @len: length of the NAND region
+ *
+ * Default implementation for mtd->_max_bad_blocks(). Only works if
+ * nand->memorg.max_bad_eraseblocks_per_lun is > 0.
+ *
+ * Return: a positive number encoding the maximum number of eraseblocks on a
+ * portion of memory, a negative error code otherwise.
+ */
+int nanddev_mtd_max_bad_blocks(struct mtd_info *mtd, loff_t offs, size_t len)
+{
+	struct nand_device *nand = mtd_to_nanddev(mtd);
+	struct nand_pos pos, end;
+	unsigned int max_bb = 0;
+
+	if (!nand->memorg.max_bad_eraseblocks_per_lun)
+		return -ENOTSUPP;
+
+	nanddev_offs_to_pos(nand, offs, &pos);
+	nanddev_offs_to_pos(nand, offs + len, &end);
+
+	for (nanddev_offs_to_pos(nand, offs, &pos);
+	     nanddev_pos_cmp(&pos, &end) < 0;
+	     nanddev_pos_next_lun(nand, &pos))
+		max_bb += nand->memorg.max_bad_eraseblocks_per_lun;
+
+	return max_bb;
+}
+EXPORT_SYMBOL_GPL(nanddev_mtd_max_bad_blocks);
+
+/**
+ * nanddev_get_ecc_engine() - Find and get a suitable ECC engine
+ * @nand: NAND device
+ */
+static int nanddev_get_ecc_engine(struct nand_device *nand)
+{
+	int engine_type;
+
+	/* Read the user desires in terms of ECC engine/configuration */
+	of_get_nand_ecc_user_config(nand);
+
+	engine_type = nand->ecc.user_conf.engine_type;
+	if (engine_type == NAND_ECC_ENGINE_TYPE_INVALID)
+		engine_type = nand->ecc.defaults.engine_type;
+
+	switch (engine_type) {
+	case NAND_ECC_ENGINE_TYPE_NONE:
+		return 0;
+	case NAND_ECC_ENGINE_TYPE_SOFT:
+		nand->ecc.engine = nand_ecc_get_sw_engine(nand);
+		break;
+	case NAND_ECC_ENGINE_TYPE_ON_DIE:
+		nand->ecc.engine = nand_ecc_get_on_die_hw_engine(nand);
+		break;
+	case NAND_ECC_ENGINE_TYPE_ON_HOST:
+		nand->ecc.engine = nand_ecc_get_on_host_hw_engine(nand);
+		if (PTR_ERR(nand->ecc.engine) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+		break;
+	default:
+		pr_err("Missing ECC engine type\n");
+	}
+
+	if (!nand->ecc.engine)
+		return  -EINVAL;
+
+	return 0;
+}
+
+/**
+ * nanddev_put_ecc_engine() - Dettach and put the in-use ECC engine
+ * @nand: NAND device
+ */
+static int nanddev_put_ecc_engine(struct nand_device *nand)
+{
+	switch (nand->ecc.ctx.conf.engine_type) {
+	case NAND_ECC_ENGINE_TYPE_ON_HOST:
+		nand_ecc_put_on_host_hw_engine(nand);
+		break;
+	case NAND_ECC_ENGINE_TYPE_NONE:
+	case NAND_ECC_ENGINE_TYPE_SOFT:
+	case NAND_ECC_ENGINE_TYPE_ON_DIE:
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/**
+ * nanddev_find_ecc_configuration() - Find a suitable ECC configuration
+ * @nand: NAND device
+ */
+static int nanddev_find_ecc_configuration(struct nand_device *nand)
+{
+	int ret;
+
+	if (!nand->ecc.engine)
+		return -ENOTSUPP;
+
+	ret = nand_ecc_init_ctx(nand);
+	if (ret)
+		return ret;
+
+	if (!nand_ecc_is_strong_enough(nand))
+		pr_warn("WARNING: %s: the ECC used on your system is too weak compared to the one required by the NAND chip\n",
+			nand->mtd.name);
+
+	return 0;
+}
+
+/**
+ * nanddev_ecc_engine_init() - Initialize an ECC engine for the chip
+ * @nand: NAND device
+ */
+int nanddev_ecc_engine_init(struct nand_device *nand)
+{
+	int ret;
+
+	/* Look for the ECC engine to use */
+	ret = nanddev_get_ecc_engine(nand);
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			pr_err("No ECC engine found\n");
+
+		return ret;
+	}
+
+	/* No ECC engine requested */
+	if (!nand->ecc.engine)
+		return 0;
+
+	/* Configure the engine: balance user input and chip requirements */
+	ret = nanddev_find_ecc_configuration(nand);
+	if (ret) {
+		pr_err("No suitable ECC configuration\n");
+		nanddev_put_ecc_engine(nand);
+
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nanddev_ecc_engine_init);
+
+/**
+ * nanddev_ecc_engine_cleanup() - Cleanup ECC engine initializations
+ * @nand: NAND device
+ */
+void nanddev_ecc_engine_cleanup(struct nand_device *nand)
+{
+	if (nand->ecc.engine)
+		nand_ecc_cleanup_ctx(nand);
+
+	nanddev_put_ecc_engine(nand);
+}
+EXPORT_SYMBOL_GPL(nanddev_ecc_engine_cleanup);
+
+/**
+ * nanddev_init() - Initialize a NAND device
+ * @nand: NAND device
+ * @ops: NAND device operations
+ * @owner: NAND device owner
+ *
+ * Initializes a NAND device object. Consistency checks are done on @ops and
+ * @nand->memorg. Also takes care of initializing the BBT.
+ *
+ * Return: 0 in case of success, a negative error code otherwise.
+ */
+int nanddev_init(struct nand_device *nand, const struct nand_ops *ops,
+		 struct module *owner)
+{
+	struct mtd_info *mtd = nanddev_to_mtd(nand);
+	struct nand_memory_organization *memorg = nanddev_get_memorg(nand);
+
+	if (!nand || !ops)
+		return -EINVAL;
+
+	if (!ops->erase || !ops->markbad || !ops->isbad)
+		return -EINVAL;
+
+	if (!memorg->bits_per_cell || !memorg->pagesize ||
+	    !memorg->pages_per_eraseblock || !memorg->eraseblocks_per_lun ||
+	    !memorg->planes_per_lun || !memorg->luns_per_target ||
+	    !memorg->ntargets)
+		return -EINVAL;
+
+	nand->rowconv.eraseblock_addr_shift =
+					fls(memorg->pages_per_eraseblock - 1);
+	nand->rowconv.lun_addr_shift = fls(memorg->eraseblocks_per_lun - 1) +
+				       nand->rowconv.eraseblock_addr_shift;
+
+	nand->ops = ops;
+
+	mtd->type = memorg->bits_per_cell == 1 ?
+		    MTD_NANDFLASH : MTD_MLCNANDFLASH;
+	mtd->flags = MTD_CAP_NANDFLASH;
+	mtd->erasesize = memorg->pagesize * memorg->pages_per_eraseblock;
+	mtd->writesize = memorg->pagesize;
+	mtd->writebufsize = memorg->pagesize;
+	mtd->oobsize = memorg->oobsize;
+	mtd->size = nanddev_size(nand);
+	mtd->owner = owner;
+
+	return nanddev_bbt_init(nand);
+}
+EXPORT_SYMBOL_GPL(nanddev_init);
+
+/**
+ * nanddev_cleanup() - Release resources allocated in nanddev_init()
+ * @nand: NAND device
+ *
+ * Basically undoes what has been done in nanddev_init().
+ */
+void nanddev_cleanup(struct nand_device *nand)
+{
+	if (nanddev_bbt_is_initialized(nand))
+		nanddev_bbt_cleanup(nand);
+}
+EXPORT_SYMBOL_GPL(nanddev_cleanup);
+
+MODULE_DESCRIPTION("Generic NAND framework");
+MODULE_AUTHOR("Boris Brezillon <boris.brezillon@free-electrons.com>");
+MODULE_LICENSE("GPL v2");