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
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
|
From bec69bb8e85151729014d859106dcc3fe652b1d4 Mon Sep 17 00:00:00 2001
From: Boris BREZILLON <boris.brezillon@free-electrons.com>
Date: Mon, 28 Jul 2014 14:45:40 +0200
Subject: [PATCH] mtd: nand: Add page status table (pst)
Page status table is an byte array storing pages status.
It defines 3 status:
- unknown: the page has not been read yet and we do not know its current
state
- empty: the page contains only FFs
- filled: the page has been filled with data
Care must be taken: an empty page does not mean it can be written, because
it might have already been written with only FFs.
These page status are useful to check wether the controller should try to
correct errors (using ECC) or a derandomize data (using a randomizer
block).
Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
drivers/mtd/nand/nand_base.c | 154 +++++++++++++++++++++++++++++++++++++++++++
include/linux/mtd/nand.h | 21 ++++++
2 files changed, 175 insertions(+)
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index a30b67f..8a5d12e 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -1102,6 +1102,138 @@ int nand_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
EXPORT_SYMBOL(nand_lock);
/**
+ * nand_page_is_empty - check wether a NAND page contains only FFs
+ * @mtd: mtd info
+ * @data: data buffer
+ * @oob: oob buffer
+ *
+ * Reads the data stored in the databuf buffer and check if it contains only
+ * FFs.
+ *
+ * Return true if it does else return false.
+ */
+bool nand_page_is_empty(struct mtd_info *mtd, void *data, void *oob)
+{
+ u8 *buf;
+ int length;
+ u32 pattern = 0xffffffff;
+ int bitflips = 0;
+ int cnt;
+
+ buf = data;
+ length = mtd->writesize;
+ while (length) {
+ cnt = length < sizeof(pattern) ? length : sizeof(pattern);
+ if (memcmp(&pattern, buf, cnt)) {
+ int i;
+ for (i = 0; i < cnt * BITS_PER_BYTE; i++) {
+ if (!(buf[i / BITS_PER_BYTE] &
+ (1 << (i % BITS_PER_BYTE)))) {
+ bitflips++;
+ if (bitflips > mtd->ecc_strength)
+ return false;
+ }
+ }
+ }
+
+ buf += sizeof(pattern);
+ length -= sizeof(pattern);
+ }
+
+ buf = oob;
+ length = mtd->oobsize;
+ while (length) {
+ cnt = length < sizeof(pattern) ? length : sizeof(pattern);
+ if (memcmp(&pattern, buf, cnt)) {
+ int i;
+ for (i = 0; i < cnt * BITS_PER_BYTE; i++) {
+ if (!(buf[i / BITS_PER_BYTE] &
+ (1 << (i % BITS_PER_BYTE)))) {
+ bitflips++;
+ if (bitflips > mtd->ecc_strength)
+ return false;
+ }
+ }
+ }
+
+ buf += sizeof(pattern);
+ length -= sizeof(pattern);
+ }
+
+ return true;
+}
+EXPORT_SYMBOL(nand_page_is_empty);
+
+/**
+ * nand_page_get_status - retrieve page status from the page status table (pst)
+ * @mtd: mtd info
+ * @page: page you want to get status on
+ *
+ * Return the page status.
+ */
+int nand_page_get_status(struct mtd_info *mtd, int page)
+{
+ struct nand_chip *chip = mtd->priv;
+ u8 shift = (page % 4) * 2;
+ uint64_t offset = page / 4;
+ int ret = NAND_PAGE_STATUS_UNKNOWN;
+
+ if (chip->pst)
+ ret = (chip->pst[offset] >> shift) & 0x3;
+
+ return ret;
+}
+EXPORT_SYMBOL(nand_page_get_status);
+
+/**
+ * nand_page_set_status - assign page status from in the page status table
+ * @mtd: mtd info
+ * @page: page you want to get status on
+ * @status: new status to assign
+ */
+void nand_page_set_status(struct mtd_info *mtd, int page,
+ enum nand_page_status status)
+{
+ struct nand_chip *chip = mtd->priv;
+ u8 shift;
+ uint64_t offset;
+
+ if (!chip->pst)
+ return;
+
+ shift = (page % 4) * 2;
+ offset = page / 4;
+ chip->pst[offset] &= ~(0x3 << shift);
+ chip->pst[offset] |= (status & 0x3) << shift;
+}
+EXPORT_SYMBOL(nand_page_set_status);
+
+/**
+ * nand_pst_create - create a page status table
+ * @mtd: mtd info
+ *
+ * Allocate a page status table and assign it to the mtd device.
+ *
+ * Returns 0 in case of success or -ERRNO in case of error.
+ */
+int nand_pst_create(struct mtd_info *mtd)
+{
+ struct nand_chip *chip = mtd->priv;
+
+ if (chip->pst)
+ return 0;
+
+ chip->pst = kzalloc(mtd->size >>
+ (chip->page_shift + mtd->subpage_sft + 2),
+ GFP_KERNEL);
+ if (!chip->pst)
+ return -ENOMEM;
+
+ return 0;
+}
+EXPORT_SYMBOL(nand_pst_create);
+
+/**
* nand_read_page_raw - [INTERN] read raw page data without ecc
* @mtd: mtd info structure
* @chip: nand chip info structure
@@ -2539,6 +2671,7 @@ static int nand_do_write_ops(struct mtd_info *mtd, loff_t to,
uint8_t *wbuf = buf;
int use_bufpoi;
int part_pagewr = (column || writelen < (mtd->writesize - 1));
+ int subpage;
if (part_pagewr)
use_bufpoi = 1;
@@ -2574,6 +2707,14 @@ static int nand_do_write_ops(struct mtd_info *mtd, loff_t to,
if (ret)
break;
+ for (subpage = column / chip->subpagesize;
+ subpage < (column + writelen) / chip->subpagesize;
+ subpage++)
+ nand_page_set_status(mtd,
+ (page << mtd->subpage_sft) +
+ subpage,
+ NAND_PAGE_FILLED);
+
writelen -= bytes;
if (!writelen)
break;
@@ -2979,6 +3120,7 @@ int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
int page, status, pages_per_block, ret, chipnr;
struct nand_chip *chip = mtd->priv;
loff_t len;
+ int i;
pr_debug("%s: start = 0x%012llx, len = %llu\n",
__func__, (unsigned long long)instr->addr,
@@ -3051,6 +3193,18 @@ int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
goto erase_exit;
}
+ for (i = 0; i < pages_per_block; i++) {
+ int subpage;
+ for (subpage = 0;
+ subpage < 1 << mtd->subpage_sft;
+ subpage++) {
+ nand_page_set_status(mtd,
+ ((page + i) << mtd->subpage_sft) +
+ subpage,
+ NAND_PAGE_EMPTY);
+ }
+ }
+
/* Increment page address and decrement length */
len -= (1ULL << chip->phys_erase_shift);
page += pages_per_block;
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 5616f51..4f7ca8d 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -521,6 +521,24 @@ struct nand_ecc_ctrl {
int page);
};
+/*
+ * Constants for page status
+ */
+enum nand_page_status {
+ NAND_PAGE_STATUS_UNKNOWN,
+ NAND_PAGE_EMPTY,
+ NAND_PAGE_FILLED,
+};
+
+bool nand_page_is_empty(struct mtd_info *mtd, void *data, void *oob);
+
+int nand_page_get_status(struct mtd_info *mtd, int page);
+
+void nand_page_set_status(struct mtd_info *mtd, int page,
+ enum nand_page_status status);
+
+int nand_pst_create(struct mtd_info *mtd);
+
/**
* struct nand_buffers - buffer structure for read/write
* @ecccalc: buffer pointer for calculated ECC, size is oobsize.
@@ -630,6 +648,7 @@ struct nand_buffers {
* @bbt_md: [REPLACEABLE] bad block table mirror descriptor
* @badblock_pattern: [REPLACEABLE] bad block scan pattern used for initial
* bad block scan.
+ * @pst: [INTERN] page status table
* @controller: [REPLACEABLE] a pointer to a hardware controller
* structure which is shared among multiple independent
* devices.
@@ -718,6 +737,8 @@ struct nand_chip {
struct nand_bbt_descr *badblock_pattern;
+ uint8_t *pst;
+
struct list_head partitions;
struct mutex part_lock;
|
