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Subject[PATCH 6/8] UBI: replace MTD_UBI_BEB_LIMIT with module parameter
Date
This patch provides the possibility to adjust the "maximum expected number of
bad blocks per 1024 blocks" (max_beb_per1024) for each mtd device.

The majority of NAND devices have their max_beb_per1024 equal to 20, but
sometimes it's more.
Now, we can adjust that via a kernel parameter:
ubi.mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024]]

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
---
drivers/mtd/ubi/Kconfig | 2 ++
drivers/mtd/ubi/build.c | 38 ++++++++++++++++++++++++--------------
2 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/drivers/mtd/ubi/Kconfig b/drivers/mtd/ubi/Kconfig
index f326877..8b67bac 100644
--- a/drivers/mtd/ubi/Kconfig
+++ b/drivers/mtd/ubi/Kconfig
@@ -51,6 +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 kernel parameter ubi.mtd.
+
Leave the default value if unsure.

config MTD_UBI_GLUEBI
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index ec7311f..cc05022 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -47,7 +47,7 @@
#define MTD_PARAM_LEN_MAX 64

/* Maximum number of comma-separated items in ht 'mtd=' parameter */
-#define MTD_PARAM_MAX_COUNT 2
+#define MTD_PARAM_MAX_COUNT 3

#ifdef CONFIG_MTD_UBI_MODULE
#define ubi_is_module() 1
@@ -60,10 +60,12 @@
* @name: MTD character device node path, MTD device name, or MTD device number
* string
* @vid_hdr_offs: VID header offset
+ * @max_beb_per1024: maximum expected number of bad blocks per 1024 erase blocks
*/
struct mtd_dev_param {
char name[MTD_PARAM_LEN_MAX];
int vid_hdr_offs;
+ int max_beb_per1024;
};

/* Numbers of elements set in the @mtd_dev_param array */
@@ -1222,8 +1224,7 @@ static int __init ubi_init(void)

mutex_lock(&ubi_devices_mutex);
err = ubi_attach_mtd_dev(mtd, UBI_DEV_NUM_AUTO,
- p->vid_hdr_offs,
- CONFIG_MTD_UBI_BEB_LIMIT);
+ p->vid_hdr_offs, p->max_beb_per1024);
mutex_unlock(&ubi_devices_mutex);
if (err < 0) {
ubi_err("cannot attach mtd%d", mtd->index);
@@ -1343,6 +1344,7 @@ static int __init ubi_mtd_param_parse(const char *val, struct kernel_param *kp)
char buf[MTD_PARAM_LEN_MAX];
char *pbuf = &buf[0];
char *tokens[MTD_PARAM_MAX_COUNT];
+ int err;

if (!val)
return -EINVAL;
@@ -1390,23 +1392,31 @@ static int __init ubi_mtd_param_parse(const char *val, struct kernel_param *kp)
if (p->vid_hdr_offs < 0)
return p->vid_hdr_offs;

+ if (tokens[2]) {
+ err = kstrtoint(tokens[2], 10, &p->max_beb_per1024);
+ if (err) {
+ pr_err("UBI error: bad value for max_beb_per1024 parameter: %s",
+ tokens[2]);
+ return -EINVAL;
+ }
+ }
+
mtd_devs += 1;
return 0;
}

module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 000);
-MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: "
- "mtd=<name|num|path>[,<vid_hdr_offs>].\n"
+MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024]].\n"
"Multiple \"mtd\" parameters may be specified.\n"
- "MTD devices may be specified by their number, name, or "
- "path to the MTD character device node.\n"
- "Optional \"vid_hdr_offs\" parameter specifies UBI VID "
- "header position to be used by UBI.\n"
- "Example 1: mtd=/dev/mtd0 - attach MTD device "
- "/dev/mtd0.\n"
- "Example 2: mtd=content,1984 mtd=4 - attach MTD device "
- "with name \"content\" using VID header offset 1984, and "
- "MTD device number 4 with default VID header offset.");
+ "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
+ "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0 or not set)\n"
+ "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
+ __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0 or not set)\n"
+ "\n"
+ "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
+ "Example 2: mtd=content,1984 mtd=4 - attach MTD device with name \"content\" using VID header offset 1984, and MTD device number 4 with default VID header offset.\n"
+ "Example 3: mtd=/dev/mtd1,0,25 - attach MTD device /dev/mtd1 using default VID header offset and reserve 25*nand_size_in_blocks/1024 erase blocks for bad block handling.\n"
+ "\t(e.g. if the NAND *chipset* has 4096 PEB, 100 will be reserved for this UBI device).");

MODULE_VERSION(__stringify(UBI_VERSION));
MODULE_DESCRIPTION("UBI - Unsorted Block Images");
--
1.7.2.5


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