fa4dc86e98
MEMREAD is a new ioctl for MTD character devices that was first included in Linux 6.1. It allows userspace applications to use the Linux kernel's OOB autoplacement mechanism while reading data from NAND devices. The Yafut tool needs this ioctl to do its job. Signed-off-by: Michał Kępień <openwrt@kempniu.pl>
74 lines
2.5 KiB
Diff
74 lines
2.5 KiB
Diff
From e237285113963bd1dd2e925770aa8b3aa8a1894c Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Micha=C5=82=20K=C4=99pie=C5=84?= <kernel@kempniu.pl>
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Date: Wed, 29 Jun 2022 14:57:34 +0200
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Subject: [PATCH 1/4] mtd: track maximum number of bitflips for each read
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request
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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mtd_read_oob() callers are currently oblivious to the details of ECC
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errors detected during the read operation - they only learn (through the
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return value) whether any corrected bitflips or uncorrectable errors
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occurred. More detailed ECC information can be useful to user-space
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applications for making better-informed choices about moving data
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around.
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Extend struct mtd_oob_ops with a pointer to a newly-introduced struct
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mtd_req_stats and set its 'max_bitflips' field to the maximum number of
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bitflips found in a single ECC step during the read operation performed
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by mtd_read_oob(). This is a prerequisite for ultimately passing that
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value back to user space.
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Suggested-by: Boris Brezillon <boris.brezillon@collabora.com>
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Signed-off-by: Michał Kępień <kernel@kempniu.pl>
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Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
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Link: https://lore.kernel.org/linux-mtd/20220629125737.14418-2-kernel@kempniu.pl
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---
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drivers/mtd/mtdcore.c | 5 +++++
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include/linux/mtd/mtd.h | 5 +++++
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2 files changed, 10 insertions(+)
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--- a/drivers/mtd/mtdcore.c
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+++ b/drivers/mtd/mtdcore.c
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@@ -1669,6 +1669,9 @@ int mtd_read_oob(struct mtd_info *mtd, l
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if (!master->_read_oob && (!master->_read || ops->oobbuf))
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return -EOPNOTSUPP;
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+ if (ops->stats)
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+ memset(ops->stats, 0, sizeof(*ops->stats));
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+
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if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
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ret_code = mtd_io_emulated_slc(mtd, from, true, ops);
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else
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@@ -1686,6 +1689,8 @@ int mtd_read_oob(struct mtd_info *mtd, l
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return ret_code;
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if (mtd->ecc_strength == 0)
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return 0; /* device lacks ecc */
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+ if (ops->stats)
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+ ops->stats->max_bitflips = ret_code;
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return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
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}
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EXPORT_SYMBOL_GPL(mtd_read_oob);
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--- a/include/linux/mtd/mtd.h
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+++ b/include/linux/mtd/mtd.h
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@@ -40,6 +40,10 @@ struct mtd_erase_region_info {
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unsigned long *lockmap; /* If keeping bitmap of locks */
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};
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+struct mtd_req_stats {
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+ unsigned int max_bitflips;
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+};
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+
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/**
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* struct mtd_oob_ops - oob operation operands
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* @mode: operation mode
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@@ -70,6 +74,7 @@ struct mtd_oob_ops {
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uint32_t ooboffs;
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uint8_t *datbuf;
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uint8_t *oobbuf;
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+ struct mtd_req_stats *stats;
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};
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#define MTD_MAX_OOBFREE_ENTRIES_LARGE 32
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