From db7e21c21f293d52f5363fe8d9ee91d6bd0a503a Mon Sep 17 00:00:00 2001
From: Richard Genoud <richard.genoud@gmail.com>
Date: Mon, 20 Aug 2012 18:00:15 +0200
Subject: [PATCH] UBI: add max_beb_per1024 to attach ioctl
This patch provides a possibility to set the "maximum expected number of
bad blocks per 1024 blocks" (max_beb_per1024) for each mtd device using
the UBI_IOCATT ioctl.
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
---
drivers/mtd/ubi/Kconfig | 3 ++-
drivers/mtd/ubi/cdev.c | 2 +-
include/mtd/ubi-user.h | 16 +++++++++++++++-
3 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/ubi/Kconfig b/drivers/mtd/ubi/Kconfig
index 3e185e46cf6ce..271a842f8c393 100644
--- a/drivers/mtd/ubi/Kconfig
+++ b/drivers/mtd/ubi/Kconfig
@@ -51,7 +51,8 @@ config MTD_UBI_BEB_LIMIT
MTD partitions of the same size, UBI will reserve 40 eraseblocks when
attaching a partition.
- This option can be overridden by the "mtd=" UBI module parameter.
+ This option can be overridden by the "mtd=" UBI module parameter or
+ by the "attach" ioctl.
Leave the default value if unsure.
diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index 619f9144f9905..7885dc0934ceb 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -1011,7 +1011,7 @@ static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
*/
mutex_lock(&ubi_devices_mutex);
err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset,
- CONFIG_MTD_UBI_BEB_LIMIT);
+ req.max_beb_per1024);
mutex_unlock(&ubi_devices_mutex);
if (err < 0)
put_mtd_device(mtd);
diff --git a/include/mtd/ubi-user.h b/include/mtd/ubi-user.h
index 8787349fbafe2..53cae1e11e57e 100644
--- a/include/mtd/ubi-user.h
+++ b/include/mtd/ubi-user.h
@@ -222,6 +222,7 @@ enum {
* @ubi_num: UBI device number to create
* @mtd_num: MTD device number to attach
* @vid_hdr_offset: VID header offset (use defaults if %0)
+ * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
* @padding: reserved for future, not used, has to be zeroed
*
* This data structure is used to specify MTD device UBI has to attach and the
@@ -245,12 +246,25 @@ enum {
* be 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
* aligned, which is OK, as UBI is clever enough to realize this is 4th
* sub-page of the first page and add needed padding.
+ *
+ * The @max_beb_per1024 is the maximum amount of bad PEBs UBI expects on the
+ * UBI device per 1024 eraseblocks. This value is often given in an other form
+ * in the NAND datasheet (min NVB i.e. minimal number of valid blocks). The
+ * maximum expected bad eraseblocks per 1024 is then:
+ * 1024 * (1 - MinNVB / MaxNVB)
+ * Which gives 20 for most NAND devices. This limit is used in order to derive
+ * amount of eraseblock UBI reserves for handling new bad blocks. If the device
+ * has more bad eraseblocks than this limit, UBI does not reserve any physical
+ * eraseblocks for new bad eraseblocks, but attempts to use available
+ * eraseblocks (if any). The accepted range is 0-768. If 0 is given, the
+ * default kernel value of %CONFIG_MTD_UBI_BEB_LIMIT will be used.
*/
struct ubi_attach_req {
__s32 ubi_num;
__s32 mtd_num;
__s32 vid_hdr_offset;
- __s8 padding[12];
+ __s16 max_beb_per1024;
+ __s8 padding[10];
};
/**
--
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