From 4ccf8cffa963c7b5bdc6d455ea9417084ee49aa8 Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Wed, 16 Jan 2008 15:44:24 +0200 Subject: UBI: add auto-resize feature The problem: NAND flashes have different amount of initial bad physical eraseblocks (marked as bad by the manufacturer). For example, for 256MiB Samsung OneNAND flash there might be from 0 to 40 bad initial eraseblocks, which is about 2%. When UBI is used as the base system, one needs to know the exact amount of good physical eraseblocks, because this number is needed to create the UBI image which is put to the devices during production. But this number is not know, which forces us to use the minimum number of good physical eraseblocks. And UBI additionally reserves some percentage of physical eraseblocks for bad block handling (default is 1%), so we have 1-3% of PEBs reserved at the end, depending on the amount of initial bad PEBs. But it is desired to always have 1% (or more, depending on the configuration). Solution: this patch adds an "auto-resize" flag to the volume table. The volume which has the "auto-resize" flag will automatically be re-sized (enlarged) on the first UBI initialization. UBI clears the flag when the volume is re-sized. Only one volume may have the "auto-resize" flag. So, the production UBI image may have one volume with "auto-resize" flag set, and its size is automatically adjusted on the first boot of the device. Signed-off-by: Artem Bityutskiy --- include/mtd/ubi-header.h | 43 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 41 insertions(+), 2 deletions(-) (limited to 'include/mtd') diff --git a/include/mtd/ubi-header.h b/include/mtd/ubi-header.h index 74efa7763479..69d5d7e22899 100644 --- a/include/mtd/ubi-header.h +++ b/include/mtd/ubi-header.h @@ -57,6 +57,43 @@ enum { UBI_VID_STATIC = 2 }; +/* + * Volume flags used in the volume table record. + * + * @UBI_VTBL_AUTORESIZE_FLG: auto-resize this volume + * + * %UBI_VTBL_AUTORESIZE_FLG flag can be set only for one volume in the volume + * table. UBI automatically re-sizes the volume which has this flag and makes + * the volume to be of largest possible size. This means that if after the + * initialization UBI finds out that there are available physical eraseblocks + * present on the device, it automatically appends all of them to the volume + * (the physical eraseblocks reserved for bad eraseblocks handling and other + * reserved physical eraseblocks are not taken). So, if there is a volume with + * the %UBI_VTBL_AUTORESIZE_FLG flag set, the amount of available logical + * eraseblocks will be zero after UBI is loaded, because all of them will be + * reserved for this volume. Note, the %UBI_VTBL_AUTORESIZE_FLG bit is cleared + * after the volume had been initialized. + * + * The auto-resize feature is useful for device production purposes. For + * example, different NAND flash chips may have different amount of initial bad + * eraseblocks, depending of particular chip instance. Manufacturers of NAND + * chips usually guarantee that the amount of initial bad eraseblocks does not + * exceed certain percent, e.g. 2%. When one creates an UBI image which will be + * flashed to the end devices in production, he does not know the exact amount + * of good physical eraseblocks the NAND chip on the device will have, but this + * number is required to calculate the volume sized and put them to the volume + * table of the UBI image. In this case, one of the volumes (e.g., the one + * which will store the root file system) is marked as "auto-resizable", and + * UBI will adjust its size on the first boot if needed. + * + * Note, first UBI reserves some amount of physical eraseblocks for bad + * eraseblock handling, and then re-sizes the volume, not vice-versa. This + * means that the pool of reserved physical eraseblocks will always be present. + */ +enum { + UBI_VTBL_AUTORESIZE_FLG = 0x01, +}; + /* * Compatibility constants used by internal volumes. * @@ -289,7 +326,8 @@ struct ubi_vid_hdr { * @upd_marker: if volume update was started but not finished * @name_len: volume name length * @name: the volume name - * @padding2: reserved, zeroes + * @flags: volume flags (%UBI_VTBL_AUTORESIZE_FLG) + * @padding: reserved, zeroes * @crc: a CRC32 checksum of the record * * The volume table records are stored in the volume table, which is stored in @@ -324,7 +362,8 @@ struct ubi_vtbl_record { __u8 upd_marker; __be16 name_len; __u8 name[UBI_VOL_NAME_MAX+1]; - __u8 padding2[24]; + __u8 flags; + __u8 padding[23]; __be32 crc; } __attribute__ ((packed)); -- cgit v1.2.3 From 91f2d53cd75a8fa3557246af965155208c4c69a7 Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Thu, 24 Jan 2008 11:23:23 +0200 Subject: UBI: add layout volume information Add more information about layout volume to make userspace tools use the macros instead of constants. Also rename UBI_LAYOUT_VOL_ID to make it consistent with other macros. Signed-off-by: Artem Bityutskiy --- include/mtd/ubi-header.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include/mtd') diff --git a/include/mtd/ubi-header.h b/include/mtd/ubi-header.h index 69d5d7e22899..292f916ea564 100644 --- a/include/mtd/ubi-header.h +++ b/include/mtd/ubi-header.h @@ -299,7 +299,9 @@ struct ubi_vid_hdr { /* The layout volume contains the volume table */ -#define UBI_LAYOUT_VOL_ID UBI_INTERNAL_VOL_START +#define UBI_LAYOUT_VOLUME_ID UBI_INTERNAL_VOL_START +#define UBI_LAYOUT_VOLUME_TYPE UBI_VID_DYNAMIC +#define UBI_LAYOUT_VOLUME_ALIGN 1 #define UBI_LAYOUT_VOLUME_EBS 2 #define UBI_LAYOUT_VOLUME_NAME "layout volume" #define UBI_LAYOUT_VOLUME_COMPAT UBI_COMPAT_REJECT -- cgit v1.2.3 From 866136827b9a71c39dcb06d23ce523f719eab74b Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Thu, 24 Jan 2008 16:15:14 +0200 Subject: UBI: introduce atomic LEB change ioctl We have to be able to change individual LEBs for utilities like ubifsck, ubifstune. For example, ubifsck has to be able to fix errors on the media, ubifstune has to be able to change the the superblock, hence this ioctl. Signed-off-by: Artem Bityutskiy --- include/mtd/ubi-user.h | 51 ++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 47 insertions(+), 4 deletions(-) (limited to 'include/mtd') diff --git a/include/mtd/ubi-user.h b/include/mtd/ubi-user.h index 4d184a7f80a8..a7421f130cc0 100644 --- a/include/mtd/ubi-user.h +++ b/include/mtd/ubi-user.h @@ -63,7 +63,7 @@ * * Volume update should be done via the %UBI_IOCVOLUP IOCTL command of the * corresponding UBI volume character device. A pointer to a 64-bit update - * size should be passed to the IOCTL. After then, UBI expects user to write + * size should be passed to the IOCTL. After this, UBI expects user to write * this number of bytes to the volume character device. The update is finished * when the claimed number of bytes is passed. So, the volume update sequence * is something like: @@ -72,6 +72,15 @@ * ioctl(fd, UBI_IOCVOLUP, &image_size); * write(fd, buf, image_size); * close(fd); + * + * Atomic eraseblock change + * ~~~~~~~~~~~~~~~~~~~~~~~~ + * + * Atomic eraseblock change operation is done via the %UBI_IOCEBCH IOCTL + * command of the corresponding UBI volume character device. A pointer to + * &struct ubi_leb_change_req has to be passed to the IOCTL. Then the user is + * expected to write the requested amount of bytes. This is similar to the + * "volume update" IOCTL. */ /* @@ -113,10 +122,29 @@ #define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, int64_t) /* An eraseblock erasure command, used for debugging, disabled by default */ #define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, int32_t) +/* An atomic eraseblock change command */ +#define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, int32_t) /* Maximum MTD device name length supported by UBI */ #define MAX_UBI_MTD_NAME_LEN 127 +/* + * UBI data type hint constants. + * + * UBI_LONGTERM: long-term data + * UBI_SHORTTERM: short-term data + * UBI_UNKNOWN: data persistence is unknown + * + * These constants are used when data is written to UBI volumes in order to + * help the UBI wear-leveling unit to find more appropriate physical + * eraseblocks. + */ +enum { + UBI_LONGTERM = 1, + UBI_SHORTTERM = 2, + UBI_UNKNOWN = 3, +}; + /* * UBI volume type constants. * @@ -125,7 +153,7 @@ */ enum { UBI_DYNAMIC_VOLUME = 3, - UBI_STATIC_VOLUME = 4, + UBI_STATIC_VOLUME = 4, }; /** @@ -137,7 +165,7 @@ enum { * * 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 + * device is passed in @ubi_num. UBI may automatically assign the number if * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in * @ubi_num. * @@ -176,7 +204,7 @@ struct ubi_attach_req { * @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 + * This structure is used by user-space programs when creating new volumes. The * @used_bytes field is only necessary when creating static volumes. * * The @alignment field specifies the required alignment of the volume logical @@ -222,4 +250,19 @@ struct ubi_rsvol_req { int32_t vol_id; } __attribute__ ((packed)); +/** + * struct ubi_leb_change_req - a data structure used in atomic logical + * eraseblock change requests. + * @lnum: logical eraseblock number to change + * @bytes: how many bytes will be written to the logical eraseblock + * @dtype: data type (%UBI_LONGTERM, %UBI_SHORTTERM, %UBI_UNKNOWN) + * @padding: reserved for future, not used, has to be zeroed + */ +struct ubi_leb_change_req { + int32_t lnum; + int32_t bytes; + uint8_t dtype; + uint8_t padding[7]; +} __attribute__ ((packed)); + #endif /* __UBI_USER_H__ */ -- cgit v1.2.3