1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
|
From e237285113963bd1dd2e925770aa8b3aa8a1894c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20K=C4=99pie=C5=84?= <kernel@kempniu.pl>
Date: Wed, 29 Jun 2022 14:57:34 +0200
Subject: [PATCH 1/4] mtd: track maximum number of bitflips for each read
request
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
mtd_read_oob() callers are currently oblivious to the details of ECC
errors detected during the read operation - they only learn (through the
return value) whether any corrected bitflips or uncorrectable errors
occurred. More detailed ECC information can be useful to user-space
applications for making better-informed choices about moving data
around.
Extend struct mtd_oob_ops with a pointer to a newly-introduced struct
mtd_req_stats and set its 'max_bitflips' field to the maximum number of
bitflips found in a single ECC step during the read operation performed
by mtd_read_oob(). This is a prerequisite for ultimately passing that
value back to user space.
Suggested-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220629125737.14418-2-kernel@kempniu.pl
---
drivers/mtd/mtdcore.c | 5 +++++
include/linux/mtd/mtd.h | 5 +++++
2 files changed, 10 insertions(+)
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -1676,6 +1676,9 @@ int mtd_read_oob(struct mtd_info *mtd, l
if (!master->_read_oob && (!master->_read || ops->oobbuf))
return -EOPNOTSUPP;
+ if (ops->stats)
+ memset(ops->stats, 0, sizeof(*ops->stats));
+
if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
ret_code = mtd_io_emulated_slc(mtd, from, true, ops);
else
@@ -1693,6 +1696,8 @@ int mtd_read_oob(struct mtd_info *mtd, l
return ret_code;
if (mtd->ecc_strength == 0)
return 0; /* device lacks ecc */
+ if (ops->stats)
+ ops->stats->max_bitflips = ret_code;
return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
}
EXPORT_SYMBOL_GPL(mtd_read_oob);
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -40,6 +40,10 @@ struct mtd_erase_region_info {
unsigned long *lockmap; /* If keeping bitmap of locks */
};
+struct mtd_req_stats {
+ unsigned int max_bitflips;
+};
+
/**
* struct mtd_oob_ops - oob operation operands
* @mode: operation mode
@@ -70,6 +74,7 @@ struct mtd_oob_ops {
uint32_t ooboffs;
uint8_t *datbuf;
uint8_t *oobbuf;
+ struct mtd_req_stats *stats;
};
#define MTD_MAX_OOBFREE_ENTRIES_LARGE 32
|
