1 files changed, 599 insertions, 0 deletions

diff --git a/drivers/mtd/nand/raw/nand_micron.c b/drivers/mtd/nand/raw/nand_micron.c
new file mode 100644
index 000000000..c01928819
--- /dev/null
+++ b/drivers/mtd/nand/raw/nand_micron.c
@@ -0,0 +1,599 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2017 Free Electrons
+ * Copyright (C) 2017 NextThing Co
+ *
+ * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
+ */
+
+#include <linux/slab.h>
+
+#include "internals.h"
+
+/*
+ * Special Micron status bit 3 indicates that the block has been
+ * corrected by on-die ECC and should be rewritten.
+ */
+#define NAND_ECC_STATUS_WRITE_RECOMMENDED	BIT(3)
+
+/*
+ * On chips with 8-bit ECC and additional bit can be used to distinguish
+ * cases where a errors were corrected without needing a rewrite
+ *
+ * Bit 4 Bit 3 Bit 0 Description
+ * ----- ----- ----- -----------
+ * 0     0     0     No Errors
+ * 0     0     1     Multiple uncorrected errors
+ * 0     1     0     4 - 6 errors corrected, recommend rewrite
+ * 0     1     1     Reserved
+ * 1     0     0     1 - 3 errors corrected
+ * 1     0     1     Reserved
+ * 1     1     0     7 - 8 errors corrected, recommend rewrite
+ */
+#define NAND_ECC_STATUS_MASK		(BIT(4) | BIT(3) | BIT(0))
+#define NAND_ECC_STATUS_UNCORRECTABLE	BIT(0)
+#define NAND_ECC_STATUS_4_6_CORRECTED	BIT(3)
+#define NAND_ECC_STATUS_1_3_CORRECTED	BIT(4)
+#define NAND_ECC_STATUS_7_8_CORRECTED	(BIT(4) | BIT(3))
+
+struct nand_onfi_vendor_micron {
+	u8 two_plane_read;
+	u8 read_cache;
+	u8 read_unique_id;
+	u8 dq_imped;
+	u8 dq_imped_num_settings;
+	u8 dq_imped_feat_addr;
+	u8 rb_pulldown_strength;
+	u8 rb_pulldown_strength_feat_addr;
+	u8 rb_pulldown_strength_num_settings;
+	u8 otp_mode;
+	u8 otp_page_start;
+	u8 otp_data_prot_addr;
+	u8 otp_num_pages;
+	u8 otp_feat_addr;
+	u8 read_retry_options;
+	u8 reserved[72];
+	u8 param_revision;
+} __packed;
+
+struct micron_on_die_ecc {
+	bool forced;
+	bool enabled;
+	void *rawbuf;
+};
+
+struct micron_nand {
+	struct micron_on_die_ecc ecc;
+};
+
+static int micron_nand_setup_read_retry(struct nand_chip *chip, int retry_mode)
+{
+	u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = {retry_mode};
+
+	return nand_set_features(chip, ONFI_FEATURE_ADDR_READ_RETRY, feature);
+}
+
+/*
+ * Configure chip properties from Micron vendor-specific ONFI table
+ */
+static int micron_nand_onfi_init(struct nand_chip *chip)
+{
+	struct nand_parameters *p = &chip->parameters;
+
+	if (p->onfi) {
+		struct nand_onfi_vendor_micron *micron = (void *)p->onfi->vendor;
+
+		chip->read_retries = micron->read_retry_options;
+		chip->ops.setup_read_retry = micron_nand_setup_read_retry;
+	}
+
+	if (p->supports_set_get_features) {
+		set_bit(ONFI_FEATURE_ADDR_READ_RETRY, p->set_feature_list);
+		set_bit(ONFI_FEATURE_ON_DIE_ECC, p->set_feature_list);
+		set_bit(ONFI_FEATURE_ADDR_READ_RETRY, p->get_feature_list);
+		set_bit(ONFI_FEATURE_ON_DIE_ECC, p->get_feature_list);
+	}
+
+	return 0;
+}
+
+static int micron_nand_on_die_4_ooblayout_ecc(struct mtd_info *mtd,
+					      int section,
+					      struct mtd_oob_region *oobregion)
+{
+	if (section >= 4)
+		return -ERANGE;
+
+	oobregion->offset = (section * 16) + 8;
+	oobregion->length = 8;
+
+	return 0;
+}
+
+static int micron_nand_on_die_4_ooblayout_free(struct mtd_info *mtd,
+					       int section,
+					       struct mtd_oob_region *oobregion)
+{
+	if (section >= 4)
+		return -ERANGE;
+
+	oobregion->offset = (section * 16) + 2;
+	oobregion->length = 6;
+
+	return 0;
+}
+
+static const struct mtd_ooblayout_ops micron_nand_on_die_4_ooblayout_ops = {
+	.ecc = micron_nand_on_die_4_ooblayout_ecc,
+	.free = micron_nand_on_die_4_ooblayout_free,
+};
+
+static int micron_nand_on_die_8_ooblayout_ecc(struct mtd_info *mtd,
+					      int section,
+					      struct mtd_oob_region *oobregion)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+
+	if (section)
+		return -ERANGE;
+
+	oobregion->offset = mtd->oobsize - chip->ecc.total;
+	oobregion->length = chip->ecc.total;
+
+	return 0;
+}
+
+static int micron_nand_on_die_8_ooblayout_free(struct mtd_info *mtd,
+					       int section,
+					       struct mtd_oob_region *oobregion)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+
+	if (section)
+		return -ERANGE;
+
+	oobregion->offset = 2;
+	oobregion->length = mtd->oobsize - chip->ecc.total - 2;
+
+	return 0;
+}
+
+static const struct mtd_ooblayout_ops micron_nand_on_die_8_ooblayout_ops = {
+	.ecc = micron_nand_on_die_8_ooblayout_ecc,
+	.free = micron_nand_on_die_8_ooblayout_free,
+};
+
+static int micron_nand_on_die_ecc_setup(struct nand_chip *chip, bool enable)
+{
+	struct micron_nand *micron = nand_get_manufacturer_data(chip);
+	u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = { 0, };
+	int ret;
+
+	if (micron->ecc.forced)
+		return 0;
+
+	if (micron->ecc.enabled == enable)
+		return 0;
+
+	if (enable)
+		feature[0] |= ONFI_FEATURE_ON_DIE_ECC_EN;
+
+	ret = nand_set_features(chip, ONFI_FEATURE_ON_DIE_ECC, feature);
+	if (!ret)
+		micron->ecc.enabled = enable;
+
+	return ret;
+}
+
+static int micron_nand_on_die_ecc_status_4(struct nand_chip *chip, u8 status,
+					   void *buf, int page,
+					   int oob_required)
+{
+	struct micron_nand *micron = nand_get_manufacturer_data(chip);
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	unsigned int step, max_bitflips = 0;
+	bool use_datain = false;
+	int ret;
+
+	if (!(status & NAND_ECC_STATUS_WRITE_RECOMMENDED)) {
+		if (status & NAND_STATUS_FAIL)
+			mtd->ecc_stats.failed++;
+
+		return 0;
+	}
+
+	/*
+	 * The internal ECC doesn't tell us the number of bitflips that have
+	 * been corrected, but tells us if it recommends to rewrite the block.
+	 * If it's the case, we need to read the page in raw mode and compare
+	 * its content to the corrected version to extract the actual number of
+	 * bitflips.
+	 * But before we do that, we must make sure we have all OOB bytes read
+	 * in non-raw mode, even if the user did not request those bytes.
+	 */
+	if (!oob_required) {
+		/*
+		 * We first check which operation is supported by the controller
+		 * before running it. This trick makes it possible to support
+		 * all controllers, even the most constraints, without almost
+		 * any performance hit.
+		 *
+		 * TODO: could be enhanced to avoid repeating the same check
+		 * over and over in the fast path.
+		 */
+		if (!nand_has_exec_op(chip) ||
+		    !nand_read_data_op(chip, chip->oob_poi, mtd->oobsize, false,
+				       true))
+			use_datain = true;
+
+		if (use_datain)
+			ret = nand_read_data_op(chip, chip->oob_poi,
+						mtd->oobsize, false, false);
+		else
+			ret = nand_change_read_column_op(chip, mtd->writesize,
+							 chip->oob_poi,
+							 mtd->oobsize, false);
+		if (ret)
+			return ret;
+	}
+
+	micron_nand_on_die_ecc_setup(chip, false);
+
+	ret = nand_read_page_op(chip, page, 0, micron->ecc.rawbuf,
+				mtd->writesize + mtd->oobsize);
+	if (ret)
+		return ret;
+
+	for (step = 0; step < chip->ecc.steps; step++) {
+		unsigned int offs, i, nbitflips = 0;
+		u8 *rawbuf, *corrbuf;
+
+		offs = step * chip->ecc.size;
+		rawbuf = micron->ecc.rawbuf + offs;
+		corrbuf = buf + offs;
+
+		for (i = 0; i < chip->ecc.size; i++)
+			nbitflips += hweight8(corrbuf[i] ^ rawbuf[i]);
+
+		offs = (step * 16) + 4;
+		rawbuf = micron->ecc.rawbuf + mtd->writesize + offs;
+		corrbuf = chip->oob_poi + offs;
+
+		for (i = 0; i < chip->ecc.bytes + 4; i++)
+			nbitflips += hweight8(corrbuf[i] ^ rawbuf[i]);
+
+		if (WARN_ON(nbitflips > chip->ecc.strength))
+			return -EINVAL;
+
+		max_bitflips = max(nbitflips, max_bitflips);
+		mtd->ecc_stats.corrected += nbitflips;
+	}
+
+	return max_bitflips;
+}
+
+static int micron_nand_on_die_ecc_status_8(struct nand_chip *chip, u8 status)
+{
+	struct mtd_info *mtd = nand_to_mtd(chip);
+
+	/*
+	 * With 8/512 we have more information but still don't know precisely
+	 * how many bit-flips were seen.
+	 */
+	switch (status & NAND_ECC_STATUS_MASK) {
+	case NAND_ECC_STATUS_UNCORRECTABLE:
+		mtd->ecc_stats.failed++;
+		return 0;
+	case NAND_ECC_STATUS_1_3_CORRECTED:
+		mtd->ecc_stats.corrected += 3;
+		return 3;
+	case NAND_ECC_STATUS_4_6_CORRECTED:
+		mtd->ecc_stats.corrected += 6;
+		/* rewrite recommended */
+		return 6;
+	case NAND_ECC_STATUS_7_8_CORRECTED:
+		mtd->ecc_stats.corrected += 8;
+		/* rewrite recommended */
+		return 8;
+	default:
+		return 0;
+	}
+}
+
+static int
+micron_nand_read_page_on_die_ecc(struct nand_chip *chip, uint8_t *buf,
+				 int oob_required, int page)
+{
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	bool use_datain = false;
+	u8 status;
+	int ret, max_bitflips = 0;
+
+	ret = micron_nand_on_die_ecc_setup(chip, true);
+	if (ret)
+		return ret;
+
+	ret = nand_read_page_op(chip, page, 0, NULL, 0);
+	if (ret)
+		goto out;
+
+	ret = nand_status_op(chip, &status);
+	if (ret)
+		goto out;
+
+	/*
+	 * We first check which operation is supported by the controller before
+	 * running it. This trick makes it possible to support all controllers,
+	 * even the most constraints, without almost any performance hit.
+	 *
+	 * TODO: could be enhanced to avoid repeating the same check over and
+	 * over in the fast path.
+	 */
+	if (!nand_has_exec_op(chip) ||
+	    !nand_read_data_op(chip, buf, mtd->writesize, false, true))
+		use_datain = true;
+
+	if (use_datain) {
+		ret = nand_exit_status_op(chip);
+		if (ret)
+			goto out;
+
+		ret = nand_read_data_op(chip, buf, mtd->writesize, false,
+					false);
+		if (!ret && oob_required)
+			ret = nand_read_data_op(chip, chip->oob_poi,
+						mtd->oobsize, false, false);
+	} else {
+		ret = nand_change_read_column_op(chip, 0, buf, mtd->writesize,
+						 false);
+		if (!ret && oob_required)
+			ret = nand_change_read_column_op(chip, mtd->writesize,
+							 chip->oob_poi,
+							 mtd->oobsize, false);
+	}
+
+	if (chip->ecc.strength == 4)
+		max_bitflips = micron_nand_on_die_ecc_status_4(chip, status,
+							       buf, page,
+							       oob_required);
+	else
+		max_bitflips = micron_nand_on_die_ecc_status_8(chip, status);
+
+out:
+	micron_nand_on_die_ecc_setup(chip, false);
+
+	return ret ? ret : max_bitflips;
+}
+
+static int
+micron_nand_write_page_on_die_ecc(struct nand_chip *chip, const uint8_t *buf,
+				  int oob_required, int page)
+{
+	int ret;
+
+	ret = micron_nand_on_die_ecc_setup(chip, true);
+	if (ret)
+		return ret;
+
+	ret = nand_write_page_raw(chip, buf, oob_required, page);
+	micron_nand_on_die_ecc_setup(chip, false);
+
+	return ret;
+}
+
+enum {
+	/* The NAND flash doesn't support on-die ECC */
+	MICRON_ON_DIE_UNSUPPORTED,
+
+	/*
+	 * The NAND flash supports on-die ECC and it can be
+	 * enabled/disabled by a set features command.
+	 */
+	MICRON_ON_DIE_SUPPORTED,
+
+	/*
+	 * The NAND flash supports on-die ECC, and it cannot be
+	 * disabled.
+	 */
+	MICRON_ON_DIE_MANDATORY,
+};
+
+#define MICRON_ID_INTERNAL_ECC_MASK	GENMASK(1, 0)
+#define MICRON_ID_ECC_ENABLED		BIT(7)
+
+/*
+ * Try to detect if the NAND support on-die ECC. To do this, we enable
+ * the feature, and read back if it has been enabled as expected. We
+ * also check if it can be disabled, because some Micron NANDs do not
+ * allow disabling the on-die ECC and we don't support such NANDs for
+ * now.
+ *
+ * This function also has the side effect of disabling on-die ECC if
+ * it had been left enabled by the firmware/bootloader.
+ */
+static int micron_supports_on_die_ecc(struct nand_chip *chip)
+{
+	const struct nand_ecc_props *requirements =
+		nanddev_get_ecc_requirements(&chip->base);
+	u8 id[5];
+	int ret;
+
+	if (!chip->parameters.onfi)
+		return MICRON_ON_DIE_UNSUPPORTED;
+
+	if (nanddev_bits_per_cell(&chip->base) != 1)
+		return MICRON_ON_DIE_UNSUPPORTED;
+
+	/*
+	 * We only support on-die ECC of 4/512 or 8/512
+	 */
+	if  (requirements->strength != 4 && requirements->strength != 8)
+		return MICRON_ON_DIE_UNSUPPORTED;
+
+	/* 0x2 means on-die ECC is available. */
+	if (chip->id.len != 5 ||
+	    (chip->id.data[4] & MICRON_ID_INTERNAL_ECC_MASK) != 0x2)
+		return MICRON_ON_DIE_UNSUPPORTED;
+
+	/*
+	 * It seems that there are devices which do not support ECC officially.
+	 * At least the MT29F2G08ABAGA / MT29F2G08ABBGA devices supports
+	 * enabling the ECC feature but don't reflect that to the READ_ID table.
+	 * So we have to guarantee that we disable the ECC feature directly
+	 * after we did the READ_ID table command. Later we can evaluate the
+	 * ECC_ENABLE support.
+	 */
+	ret = micron_nand_on_die_ecc_setup(chip, true);
+	if (ret)
+		return MICRON_ON_DIE_UNSUPPORTED;
+
+	ret = nand_readid_op(chip, 0, id, sizeof(id));
+	if (ret)
+		return MICRON_ON_DIE_UNSUPPORTED;
+
+	ret = micron_nand_on_die_ecc_setup(chip, false);
+	if (ret)
+		return MICRON_ON_DIE_UNSUPPORTED;
+
+	if (!(id[4] & MICRON_ID_ECC_ENABLED))
+		return MICRON_ON_DIE_UNSUPPORTED;
+
+	ret = nand_readid_op(chip, 0, id, sizeof(id));
+	if (ret)
+		return MICRON_ON_DIE_UNSUPPORTED;
+
+	if (id[4] & MICRON_ID_ECC_ENABLED)
+		return MICRON_ON_DIE_MANDATORY;
+
+	/*
+	 * We only support on-die ECC of 4/512 or 8/512
+	 */
+	if  (requirements->strength != 4 && requirements->strength != 8)
+		return MICRON_ON_DIE_UNSUPPORTED;
+
+	return MICRON_ON_DIE_SUPPORTED;
+}
+
+static int micron_nand_init(struct nand_chip *chip)
+{
+	struct nand_device *base = &chip->base;
+	const struct nand_ecc_props *requirements =
+		nanddev_get_ecc_requirements(base);
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	struct micron_nand *micron;
+	int ondie;
+	int ret;
+
+	micron = kzalloc(sizeof(*micron), GFP_KERNEL);
+	if (!micron)
+		return -ENOMEM;
+
+	nand_set_manufacturer_data(chip, micron);
+
+	ret = micron_nand_onfi_init(chip);
+	if (ret)
+		goto err_free_manuf_data;
+
+	chip->options |= NAND_BBM_FIRSTPAGE;
+
+	if (mtd->writesize == 2048)
+		chip->options |= NAND_BBM_SECONDPAGE;
+
+	ondie = micron_supports_on_die_ecc(chip);
+
+	if (ondie == MICRON_ON_DIE_MANDATORY &&
+	    chip->ecc.engine_type != NAND_ECC_ENGINE_TYPE_ON_DIE) {
+		pr_err("On-die ECC forcefully enabled, not supported\n");
+		ret = -EINVAL;
+		goto err_free_manuf_data;
+	}
+
+	if (chip->ecc.engine_type == NAND_ECC_ENGINE_TYPE_ON_DIE) {
+		if (ondie == MICRON_ON_DIE_UNSUPPORTED) {
+			pr_err("On-die ECC selected but not supported\n");
+			ret = -EINVAL;
+			goto err_free_manuf_data;
+		}
+
+		if (ondie == MICRON_ON_DIE_MANDATORY) {
+			micron->ecc.forced = true;
+			micron->ecc.enabled = true;
+		}
+
+		/*
+		 * In case of 4bit on-die ECC, we need a buffer to store a
+		 * page dumped in raw mode so that we can compare its content
+		 * to the same page after ECC correction happened and extract
+		 * the real number of bitflips from this comparison.
+		 * That's not needed for 8-bit ECC, because the status expose
+		 * a better approximation of the number of bitflips in a page.
+		 */
+		if (requirements->strength == 4) {
+			micron->ecc.rawbuf = kmalloc(mtd->writesize +
+						     mtd->oobsize,
+						     GFP_KERNEL);
+			if (!micron->ecc.rawbuf) {
+				ret = -ENOMEM;
+				goto err_free_manuf_data;
+			}
+		}
+
+		if (requirements->strength == 4)
+			mtd_set_ooblayout(mtd,
+					  &micron_nand_on_die_4_ooblayout_ops);
+		else
+			mtd_set_ooblayout(mtd,
+					  &micron_nand_on_die_8_ooblayout_ops);
+
+		chip->ecc.bytes = requirements->strength * 2;
+		chip->ecc.size = 512;
+		chip->ecc.strength = requirements->strength;
+		chip->ecc.algo = NAND_ECC_ALGO_BCH;
+		chip->ecc.read_page = micron_nand_read_page_on_die_ecc;
+		chip->ecc.write_page = micron_nand_write_page_on_die_ecc;
+
+		if (ondie == MICRON_ON_DIE_MANDATORY) {
+			chip->ecc.read_page_raw = nand_read_page_raw_notsupp;
+			chip->ecc.write_page_raw = nand_write_page_raw_notsupp;
+		} else {
+			if (!chip->ecc.read_page_raw)
+				chip->ecc.read_page_raw = nand_read_page_raw;
+			if (!chip->ecc.write_page_raw)
+				chip->ecc.write_page_raw = nand_write_page_raw;
+		}
+	}
+
+	return 0;
+
+err_free_manuf_data:
+	kfree(micron->ecc.rawbuf);
+	kfree(micron);
+
+	return ret;
+}
+
+static void micron_nand_cleanup(struct nand_chip *chip)
+{
+	struct micron_nand *micron = nand_get_manufacturer_data(chip);
+
+	kfree(micron->ecc.rawbuf);
+	kfree(micron);
+}
+
+static void micron_fixup_onfi_param_page(struct nand_chip *chip,
+					 struct nand_onfi_params *p)
+{
+	/*
+	 * MT29F1G08ABAFAWP-ITE:F and possibly others report 00 00 for the
+	 * revision number field of the ONFI parameter page. Assume ONFI
+	 * version 1.0 if the revision number is 00 00.
+	 */
+	if (le16_to_cpu(p->revision) == 0)
+		p->revision = cpu_to_le16(ONFI_VERSION_1_0);
+}
+
+const struct nand_manufacturer_ops micron_nand_manuf_ops = {
+	.init = micron_nand_init,
+	.cleanup = micron_nand_cleanup,
+	.fixup_onfi_param_page = micron_fixup_onfi_param_page,
+};