Root/target/linux/generic/patches-2.6.31/222-partial_eraseblock_write.patch

1--- a/drivers/mtd/mtdpart.c
2+++ b/drivers/mtd/mtdpart.c
3@@ -21,6 +21,8 @@
4 #include <linux/root_dev.h>
5 #include <linux/magic.h>
6 
7+#define MTD_ERASE_PARTIAL 0x8000 /* partition only covers parts of an erase block */
8+
9 /* Our partition linked list */
10 static LIST_HEAD(mtd_partitions);
11 
12@@ -226,13 +228,60 @@ static int part_erase(struct mtd_info *m
13         return -EROFS;
14     if (instr->addr >= mtd->size)
15         return -EINVAL;
16+
17+ instr->partial_start = false;
18+ if (mtd->flags & MTD_ERASE_PARTIAL) {
19+ size_t readlen = 0;
20+ u64 mtd_ofs;
21+
22+ instr->erase_buf = kmalloc(part->master->erasesize, GFP_ATOMIC);
23+ if (!instr->erase_buf)
24+ return -ENOMEM;
25+
26+ mtd_ofs = part->offset + instr->addr;
27+ instr->erase_buf_ofs = do_div(mtd_ofs, part->master->erasesize);
28+
29+ if (instr->erase_buf_ofs > 0) {
30+ instr->addr -= instr->erase_buf_ofs;
31+ ret = part->master->read(part->master,
32+ instr->addr + part->offset,
33+ part->master->erasesize,
34+ &readlen, instr->erase_buf);
35+
36+ instr->partial_start = true;
37+ } else {
38+ mtd_ofs = part->offset + part->mtd.size;
39+ instr->erase_buf_ofs = part->master->erasesize -
40+ do_div(mtd_ofs, part->master->erasesize);
41+
42+ if (instr->erase_buf_ofs > 0) {
43+ instr->len += instr->erase_buf_ofs;
44+ ret = part->master->read(part->master,
45+ part->offset + instr->addr +
46+ instr->len - part->master->erasesize,
47+ part->master->erasesize, &readlen,
48+ instr->erase_buf);
49+ } else {
50+ ret = 0;
51+ }
52+ }
53+ if (ret < 0) {
54+ kfree(instr->erase_buf);
55+ return ret;
56+ }
57+
58+ }
59+
60     instr->addr += part->offset;
61     ret = part->master->erase(part->master, instr);
62     if (ret) {
63         if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
64             instr->fail_addr -= part->offset;
65         instr->addr -= part->offset;
66+ if (mtd->flags & MTD_ERASE_PARTIAL)
67+ kfree(instr->erase_buf);
68     }
69+
70     return ret;
71 }
72 
73@@ -240,7 +289,25 @@ void mtd_erase_callback(struct erase_inf
74 {
75     if (instr->mtd->erase == part_erase) {
76         struct mtd_part *part = PART(instr->mtd);
77+ size_t wrlen = 0;
78 
79+ if (instr->mtd->flags & MTD_ERASE_PARTIAL) {
80+ if (instr->partial_start) {
81+ part->master->write(part->master,
82+ instr->addr, instr->erase_buf_ofs,
83+ &wrlen, instr->erase_buf);
84+ instr->addr += instr->erase_buf_ofs;
85+ } else {
86+ instr->len -= instr->erase_buf_ofs;
87+ part->master->write(part->master,
88+ instr->addr + instr->len,
89+ instr->erase_buf_ofs, &wrlen,
90+ instr->erase_buf +
91+ part->master->erasesize -
92+ instr->erase_buf_ofs);
93+ }
94+ kfree(instr->erase_buf);
95+ }
96         if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
97             instr->fail_addr -= part->offset;
98         instr->addr -= part->offset;
99@@ -472,18 +539,24 @@ static struct mtd_part *add_one_partitio
100     if ((slave->mtd.flags & MTD_WRITEABLE) &&
101         mtd_mod_by_eb(slave->offset, &slave->mtd)) {
102         /* Doesn't start on a boundary of major erase size */
103- /* FIXME: Let it be writable if it is on a boundary of
104- * _minor_ erase size though */
105- slave->mtd.flags &= ~MTD_WRITEABLE;
106- printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase block boundary -- force read-only\n",
107- part->name);
108+ slave->mtd.flags |= MTD_ERASE_PARTIAL;
109+ if (((u32) slave->mtd.size) > master->erasesize)
110+ slave->mtd.flags &= ~MTD_WRITEABLE;
111+ else
112+ slave->mtd.erasesize = slave->mtd.size;
113     }
114     if ((slave->mtd.flags & MTD_WRITEABLE) &&
115- mtd_mod_by_eb(slave->mtd.size, &slave->mtd)) {
116- slave->mtd.flags &= ~MTD_WRITEABLE;
117- printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase block -- force read-only\n",
118- part->name);
119- }
120+ mtd_mod_by_eb(slave->offset + slave->mtd.size, &slave->mtd)) {
121+ slave->mtd.flags |= MTD_ERASE_PARTIAL;
122+
123+ if ((u32) slave->mtd.size > master->erasesize)
124+ slave->mtd.flags &= ~MTD_WRITEABLE;
125+ else
126+ slave->mtd.erasesize = slave->mtd.size;
127+ }
128+ if ((slave->mtd.flags & (MTD_ERASE_PARTIAL|MTD_WRITEABLE)) == MTD_ERASE_PARTIAL)
129+ printk(KERN_WARNING"mtd: partition \"%s\" must either start or end on erase block boundary or be smaller than an erase block -- forcing read-only\n",
130+ part->name);
131 
132     slave->mtd.ecclayout = master->ecclayout;
133     if (master->block_isbad) {
134--- a/include/linux/mtd/mtd.h
135+++ b/include/linux/mtd/mtd.h
136@@ -46,6 +46,10 @@ struct erase_info {
137     u_long priv;
138     u_char state;
139     struct erase_info *next;
140+
141+ u8 *erase_buf;
142+ u32 erase_buf_ofs;
143+ bool partial_start;
144 };
145 
146 struct mtd_erase_region_info {
147

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