mtd: add a flags for partitions which should just leave smth. after them

Add support for MTDPART_OFS_RETAIN: such partitions start at the current
offset, take as much space as possible, but rain part->size bytes after
the end of the partitions for other parts. Primarily this is intended
for ts72xx arm platforms cleanup.

Artem: tweaked the patch a bit

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 3477e16be1c82249801693bcc9f8017e9f8dadd2..b73720502433c0b1474944a2d75a1228dfb0d3e3 100644 (file)
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -479,6 +479,19 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
                               (unsigned long long)cur_offset, (unsigned long long)slave->offset);
                }
        }
+       if (slave->offset == MTDPART_OFS_RETAIN) {
+               slave->offset = cur_offset;
+               if (master->size - slave->offset >= slave->mtd.size) {
+                       slave->mtd.size = master->size - slave->offset
+                                                       - slave->mtd.size;
+               } else {
+                       printk(KERN_ERR "mtd partition \"%s\" doesn't have enough space: %#llx < %#llx, disabled\n",
+                               part->name, master->size - slave->offset,
+                               slave->mtd.size);
+                       /* register to preserve ordering */
+                       goto out_register;
+               }
+       }
        if (slave->mtd.size == MTDPART_SIZ_FULL)
                slave->mtd.size = master->size - slave->offset;
 

diff --git a/include/linux/mtd/partitions.h b/include/linux/mtd/partitions.h
index 08c9c7b8b8e2f972602ec031d6a0ae5398a901ce..1431cf2609ed47e41ae9065a2f95fcbc7af45b95 100644 (file)
--- a/include/linux/mtd/partitions.h
+++ b/include/linux/mtd/partitions.h
@@ -24,7 +24,9 @@
  *     will extend to the end of the master MTD device.
  * offset: absolute starting position within the master MTD device; if
  *     defined as MTDPART_OFS_APPEND, the partition will start where the
- *     previous one ended; if MTDPART_OFS_NXTBLK, at the next erase block.
+ *     previous one ended; if MTDPART_OFS_NXTBLK, at the next erase block;
+ *     if MTDPART_OFS_RETAIN, consume as much as possible, leaving size
+ *     after the end of partition.
  * mask_flags: contains flags that have to be masked (removed) from the
  *     master MTD flag set for the corresponding MTD partition.
  *     For example, to force a read-only partition, simply adding
@@ -42,6 +44,7 @@ struct mtd_partition {
        struct nand_ecclayout *ecclayout;       /* out of band layout for this partition (NAND only) */
 };
 
+#define MTDPART_OFS_RETAIN     (-3)
 #define MTDPART_OFS_NXTBLK     (-2)
 #define MTDPART_OFS_APPEND     (-1)
 #define MTDPART_SIZ_FULL       (0)