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|
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -21,6 +21,8 @@
#include <linux/root_dev.h>
#include <linux/magic.h>
+#define MTD_ERASE_PARTIAL 0x8000 /* partition only covers parts of an erase block */
+
/* Our partition linked list */
static LIST_HEAD(mtd_partitions);
@@ -226,13 +228,60 @@ static int part_erase(struct mtd_info *m
return -EROFS;
if (instr->addr >= mtd->size)
return -EINVAL;
+
+ instr->partial_start = false;
+ if (mtd->flags & MTD_ERASE_PARTIAL) {
+ size_t readlen = 0;
+ u64 mtd_ofs;
+
+ instr->erase_buf = kmalloc(part->master->erasesize, GFP_ATOMIC);
+ if (!instr->erase_buf)
+ return -ENOMEM;
+
+ mtd_ofs = part->offset + instr->addr;
+ instr->erase_buf_ofs = do_div(mtd_ofs, part->master->erasesize);
+
+ if (instr->erase_buf_ofs > 0) {
+ instr->addr -= instr->erase_buf_ofs;
+ ret = part->master->read(part->master,
+ instr->addr + part->offset,
+ part->master->erasesize,
+ &readlen, instr->erase_buf);
+
+ instr->partial_start = true;
+ } else {
+ mtd_ofs = part->offset + part->mtd.size;
+ instr->erase_buf_ofs = part->master->erasesize -
+ do_div(mtd_ofs, part->master->erasesize);
+
+ if (instr->erase_buf_ofs > 0) {
+ instr->len += instr->erase_buf_ofs;
+ ret = part->master->read(part->master,
+ part->offset + instr->addr +
+ instr->len - part->master->erasesize,
+ part->master->erasesize, &readlen,
+ instr->erase_buf);
+ } else {
+ ret = 0;
+ }
+ }
+ if (ret < 0) {
+ kfree(instr->erase_buf);
+ return ret;
+ }
+
+ }
+
instr->addr += part->offset;
ret = part->master->erase(part->master, instr);
if (ret) {
if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
instr->fail_addr -= part->offset;
instr->addr -= part->offset;
+ if (mtd->flags & MTD_ERASE_PARTIAL)
+ kfree(instr->erase_buf);
}
+
return ret;
}
@@ -240,7 +289,25 @@ void mtd_erase_callback(struct erase_inf
{
if (instr->mtd->erase == part_erase) {
struct mtd_part *part = PART(instr->mtd);
+ size_t wrlen = 0;
+ if (instr->mtd->flags & MTD_ERASE_PARTIAL) {
+ if (instr->partial_start) {
+ part->master->write(part->master,
+ instr->addr, instr->erase_buf_ofs,
+ &wrlen, instr->erase_buf);
+ instr->addr += instr->erase_buf_ofs;
+ } else {
+ instr->len -= instr->erase_buf_ofs;
+ part->master->write(part->master,
+ instr->addr + instr->len,
+ instr->erase_buf_ofs, &wrlen,
+ instr->erase_buf +
+ part->master->erasesize -
+ instr->erase_buf_ofs);
+ }
+ kfree(instr->erase_buf);
+ }
if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
instr->fail_addr -= part->offset;
instr->addr -= part->offset;
@@ -473,18 +540,24 @@ static struct mtd_part *add_one_partitio
if ((slave->mtd.flags & MTD_WRITEABLE) &&
mtd_mod_by_eb(slave->offset, &slave->mtd)) {
/* Doesn't start on a boundary of major erase size */
- /* FIXME: Let it be writable if it is on a boundary of
- * _minor_ erase size though */
- slave->mtd.flags &= ~MTD_WRITEABLE;
- printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase block boundary -- force read-only\n",
- part->name);
+ slave->mtd.flags |= MTD_ERASE_PARTIAL;
+ if (((u32) slave->mtd.size) > master->erasesize)
+ slave->mtd.flags &= ~MTD_WRITEABLE;
+ else
+ slave->mtd.erasesize = slave->mtd.size;
}
if ((slave->mtd.flags & MTD_WRITEABLE) &&
- mtd_mod_by_eb(slave->mtd.size, &slave->mtd)) {
- slave->mtd.flags &= ~MTD_WRITEABLE;
- printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase block -- force read-only\n",
- part->name);
- }
+ mtd_mod_by_eb(slave->offset + slave->mtd.size, &slave->mtd)) {
+ slave->mtd.flags |= MTD_ERASE_PARTIAL;
+
+ if ((u32) slave->mtd.size > master->erasesize)
+ slave->mtd.flags &= ~MTD_WRITEABLE;
+ else
+ slave->mtd.erasesize = slave->mtd.size;
+ }
+ if ((slave->mtd.flags & (MTD_ERASE_PARTIAL|MTD_WRITEABLE)) == MTD_ERASE_PARTIAL)
+ 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",
+ part->name);
slave->mtd.ecclayout = master->ecclayout;
if (master->block_isbad) {
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -45,6 +45,10 @@ struct erase_info {
u_long priv;
u_char state;
struct erase_info *next;
+
+ u8 *erase_buf;
+ u32 erase_buf_ofs;
+ bool partial_start;
};
struct mtd_erase_region_info {
|
