UBI: introduce attach ioctls
Linux-MTD Mailing List
linux-mtd at lists.infradead.org
Tue Jan 8 02:59:03 EST 2008
Gitweb: http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=9b79cc0f84edecceb04b806b9014fcec1306c34d
Commit: 9b79cc0f84edecceb04b806b9014fcec1306c34d
Parent: dd38fccfbc77e12417512c38508a5283ea79a375
Author: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
AuthorDate: Tue Dec 18 18:22:16 2007 +0200
Committer: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
CommitDate: Wed Dec 26 19:15:17 2007 +0200
UBI: introduce attach ioctls
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
---
include/mtd/ubi-user.h | 80 +++++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 72 insertions(+), 8 deletions(-)
diff --git a/include/mtd/ubi-user.h b/include/mtd/ubi-user.h
index fe06ded..4d184a7 100644
--- a/include/mtd/ubi-user.h
+++ b/include/mtd/ubi-user.h
@@ -22,6 +22,21 @@
#define __UBI_USER_H__
/*
+ * UBI device creation (the same as MTD device attachment)
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * MTD devices may be attached using %UBI_IOCATT ioctl command of the UBI
+ * control device. The caller has to properly fill and pass
+ * &struct ubi_attach_req object - UBI will attach the MTD device specified in
+ * the request and return the newly created UBI device number as the ioctl
+ * return value.
+ *
+ * UBI device deletion (the same as MTD device detachment)
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * An UBI device maybe deleted with %UBI_IOCDET ioctl command of the UBI
+ * control device.
+ *
* UBI volume creation
* ~~~~~~~~~~~~~~~~~~~
*
@@ -60,11 +75,12 @@
*/
/*
- * When a new volume is created, users may either specify the volume number they
- * want to create or to let UBI automatically assign a volume number using this
- * constant.
+ * When a new UBI volume or UBI device is created, users may either specify the
+ * volume/device number they want to create or to let UBI automatically assign
+ * the number using these constants.
*/
#define UBI_VOL_NUM_AUTO (-1)
+#define UBI_DEV_NUM_AUTO (-1)
/* Maximum volume name length */
#define UBI_MAX_VOLUME_NAME 127
@@ -80,6 +96,15 @@
/* Re-size an UBI volume */
#define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
+/* IOCTL commands of the UBI control character device */
+
+#define UBI_CTRL_IOC_MAGIC 'o'
+
+/* Attach an MTD device */
+#define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
+/* Detach an MTD device */
+#define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, int32_t)
+
/* IOCTL commands of UBI volume character devices */
#define UBI_VOL_IOC_MAGIC 'O'
@@ -89,6 +114,9 @@
/* An eraseblock erasure command, used for debugging, disabled by default */
#define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, int32_t)
+/* Maximum MTD device name length supported by UBI */
+#define MAX_UBI_MTD_NAME_LEN 127
+
/*
* UBI volume type constants.
*
@@ -97,19 +125,55 @@
*/
enum {
UBI_DYNAMIC_VOLUME = 3,
- UBI_STATIC_VOLUME = 4
+ UBI_STATIC_VOLUME = 4,
+};
+
+/**
+ * struct ubi_attach_req - attach MTD device request.
+ * @ubi_num: UBI device number to create
+ * @mtd_num: MTD device number to attach
+ * @vid_hdr_offset: VID header offset (use defaults if %0)
+ * @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
+ * parameters it has to use. The number which should be assigned to the new UBI
+ * device is passed in @ubi_num. UBI may automatically assing the number if
+ * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
+ * @ubi_num.
+ *
+ * Most applications should pass %0 in @vid_hdr_offset to make UBI use default
+ * offset of the VID header within physical eraseblocks. The default offset is
+ * the next min. I/O unit after the EC header. For example, it will be offset
+ * 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
+ * it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
+ *
+ * But in rare cases, if this optimizes things, the VID header may be placed to
+ * a different offset. For example, the boot-loader might do things faster if the
+ * VID header sits at the end of the first 2KiB NAND page with 4 sub-pages. As
+ * the boot-loader would not normally need to read EC headers (unless it needs
+ * UBI in RW mode), it might be faster to calculate ECC. This is weird example,
+ * but it real-life example. So, in this example, @vid_hdr_offer would 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.
+ */
+struct ubi_attach_req {
+ int32_t ubi_num;
+ int32_t mtd_num;
+ int32_t vid_hdr_offset;
+ uint8_t padding[12];
};
/**
* struct ubi_mkvol_req - volume description data structure used in
- * volume creation requests.
+ * volume creation requests.
* @vol_id: volume number
* @alignment: volume alignment
* @bytes: volume size in bytes
* @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
- * @padding1: reserved for future, not used
+ * @padding1: reserved for future, not used, has to be zeroed
* @name_len: volume name length
- * @padding2: reserved for future, not used
+ * @padding2: reserved for future, not used, has to be zeroed
* @name: volume name
*
* This structure is used by userspace programs when creating new volumes. The
@@ -139,7 +203,7 @@ struct ubi_mkvol_req {
int8_t padding1;
int16_t name_len;
int8_t padding2[4];
- char name[UBI_MAX_VOLUME_NAME+1];
+ char name[UBI_MAX_VOLUME_NAME + 1];
} __attribute__ ((packed));
/**
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