1 --- a/drivers/mtd/mtdpart.c
2 +++ b/drivers/mtd/mtdpart.c
4 #include <linux/squashfs_fs.h>
5 #include <linux/root_dev.h>
7 +#define MTD_ERASE_PARTIAL 0x8000 /* partition only covers parts of an erase block */
9 /* Our partition linked list */
10 static LIST_HEAD(mtd_partitions);
12 @@ -214,12 +216,56 @@ static int part_erase (struct mtd_info *
14 if (instr->addr >= mtd->size)
17 + instr->partial_start = false;
18 + if (mtd->flags & MTD_ERASE_PARTIAL) {
22 + instr->erase_buf = kmalloc(part->master->erasesize, GFP_ATOMIC);
23 + if (!instr->erase_buf)
26 + instr->erase_buf_ofs = (part->offset + instr->addr) %
27 + part->master->erasesize;
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);
36 + instr->partial_start = true;
38 + instr->erase_buf_ofs = part->master->erasesize -
39 + ((part->offset + part->mtd.size) % part->master->erasesize);
41 + if (instr->erase_buf_ofs > 0) {
42 + instr->len += instr->erase_buf_ofs;
43 + ret = part->master->read(part->master,
44 + part->offset + instr->addr +
45 + instr->len - part->master->erasesize,
46 + part->master->erasesize, &readlen,
53 + kfree(instr->erase_buf);
57 instr->addr += part->offset;
58 ret = part->master->erase(part->master, instr);
59 + instr->partial_start = false;
61 if (instr->fail_addr != 0xffffffff)
62 instr->fail_addr -= part->offset;
63 instr->addr -= part->offset;
64 + if (mtd->flags & MTD_ERASE_PARTIAL)
65 + kfree(instr->erase_buf);
69 @@ -228,7 +274,25 @@ void mtd_erase_callback(struct erase_inf
71 if (instr->mtd->erase == part_erase) {
72 struct mtd_part *part = PART(instr->mtd);
75 + if (instr->mtd->flags & MTD_ERASE_PARTIAL) {
76 + if (instr->partial_start) {
77 + part->master->write(part->master,
78 + instr->addr, instr->erase_buf_ofs,
79 + &wrlen, instr->erase_buf);
80 + instr->addr += instr->erase_buf_ofs;
82 + instr->len -= instr->erase_buf_ofs;
83 + part->master->write(part->master,
84 + instr->addr + instr->len,
85 + instr->erase_buf_ofs, &wrlen,
87 + part->master->erasesize -
88 + instr->erase_buf_ofs);
90 + kfree(instr->erase_buf);
92 if (instr->fail_addr != 0xffffffff)
93 instr->fail_addr -= part->offset;
94 instr->addr -= part->offset;
95 @@ -456,17 +520,24 @@ static int add_one_partition(struct mtd_
96 if ((slave->mtd.flags & MTD_WRITEABLE) &&
97 (slave->offset % slave->mtd.erasesize)) {
98 /* Doesn't start on a boundary of major erase size */
99 - /* FIXME: Let it be writable if it is on a boundary of _minor_ erase size though */
100 - slave->mtd.flags &= ~MTD_WRITEABLE;
101 - printk ("mtd: partition \"%s\" doesn't start on an erase block boundary -- force read-only\n",
103 + slave->mtd.flags |= MTD_ERASE_PARTIAL;
104 + if (((u32) slave->mtd.size) > master->erasesize)
105 + slave->mtd.flags &= ~MTD_WRITEABLE;
107 + slave->mtd.erasesize = slave->mtd.size;
109 if ((slave->mtd.flags & MTD_WRITEABLE) &&
110 (slave->mtd.size % slave->mtd.erasesize)) {
111 - slave->mtd.flags &= ~MTD_WRITEABLE;
112 - printk ("mtd: partition \"%s\" doesn't end on an erase block -- force read-only\n",
115 + slave->mtd.flags |= MTD_ERASE_PARTIAL;
117 + if ((u32) slave->mtd.size > master->erasesize)
118 + slave->mtd.flags &= ~MTD_WRITEABLE;
120 + slave->mtd.erasesize = slave->mtd.size;
122 + if ((slave->mtd.flags & (MTD_ERASE_PARTIAL|MTD_WRITEABLE)) == MTD_ERASE_PARTIAL)
123 + 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",
126 slave->mtd.ecclayout = master->ecclayout;
127 if (master->block_isbad) {
128 --- a/include/linux/mtd/mtd.h
129 +++ b/include/linux/mtd/mtd.h
130 @@ -43,6 +43,10 @@ struct erase_info {
133 struct erase_info *next;
137 + bool partial_start;
140 struct mtd_erase_region_info {