| ------------------- | |
| UBI usage in U-Boot | |
| ------------------- | |
| UBI support in U-Boot is broken down into five separate commands. | |
| The first is the ubi command, which has six subcommands: | |
| => help ubi | |
| ubi - ubi commands | |
| Usage: | |
| ubi part [part] [offset] | |
| - Show or set current partition (with optional VID header offset) | |
| ubi info [l[ayout]] - Display volume and ubi layout information | |
| ubi create[vol] volume [size] [type] - create volume name with size | |
| ubi write[vol] address volume size - Write volume from address with size | |
| ubi write.part address volume size [fullsize] | |
| - Write part of a volume from address | |
| ubi read[vol] address volume [size] - Read volume to address with size | |
| ubi remove[vol] volume - Remove volume | |
| [Legends] | |
| volume: character name | |
| size: specified in bytes | |
| type: s[tatic] or d[ynamic] (default=dynamic) | |
| The first command that is needed to be issues is "ubi part" to connect | |
| one mtd partition to the UBI subsystem. This command will either create | |
| a new UBI device on the requested MTD partition. Or it will attach a | |
| previously created UBI device. The other UBI commands will only work | |
| when such a UBI device is attached (via "ubi part"). Here an example: | |
| => mtdparts | |
| device nor0 <1fc000000.nor_flash>, # parts = 6 | |
| #: name size offset mask_flags | |
| 0: kernel 0x00200000 0x00000000 0 | |
| 1: dtb 0x00040000 0x00200000 0 | |
| 2: root 0x00200000 0x00240000 0 | |
| 3: user 0x01ac0000 0x00440000 0 | |
| 4: env 0x00080000 0x01f00000 0 | |
| 5: u-boot 0x00080000 0x01f80000 0 | |
| active partition: nor0,0 - (kernel) 0x00200000 @ 0x00000000 | |
| defaults: | |
| mtdids : nor0=1fc000000.nor_flash | |
| mtdparts: mtdparts=1fc000000.nor_flash:2m(kernel),256k(dtb),2m(root),27392k(user),512k(env),512k(u-boot) | |
| => ubi part root | |
| Creating 1 MTD partitions on "nor0": | |
| 0x000000240000-0x000000440000 : "mtd=2" | |
| UBI: attaching mtd1 to ubi0 | |
| UBI: physical eraseblock size: 262144 bytes (256 KiB) | |
| UBI: logical eraseblock size: 262016 bytes | |
| UBI: smallest flash I/O unit: 1 | |
| UBI: VID header offset: 64 (aligned 64) | |
| UBI: data offset: 128 | |
| UBI: attached mtd1 to ubi0 | |
| UBI: MTD device name: "mtd=2" | |
| UBI: MTD device size: 2 MiB | |
| UBI: number of good PEBs: 8 | |
| UBI: number of bad PEBs: 0 | |
| UBI: max. allowed volumes: 128 | |
| UBI: wear-leveling threshold: 4096 | |
| UBI: number of internal volumes: 1 | |
| UBI: number of user volumes: 1 | |
| UBI: available PEBs: 0 | |
| UBI: total number of reserved PEBs: 8 | |
| UBI: number of PEBs reserved for bad PEB handling: 0 | |
| UBI: max/mean erase counter: 2/1 | |
| Now that the UBI device is attached, this device can be modified | |
| using the following commands: | |
| ubi info Display volume and ubi layout information | |
| ubi createvol Create UBI volume on UBI device | |
| ubi removevol Remove UBI volume from UBI device | |
| ubi read Read data from UBI volume to memory | |
| ubi write Write data from memory to UBI volume | |
| ubi write.part Write data from memory to UBI volume, in parts | |
| Here a few examples on the usage: | |
| => ubi create testvol | |
| Creating dynamic volume testvol of size 1048064 | |
| => ubi info l | |
| UBI: volume information dump: | |
| UBI: vol_id 0 | |
| UBI: reserved_pebs 4 | |
| UBI: alignment 1 | |
| UBI: data_pad 0 | |
| UBI: vol_type 3 | |
| UBI: name_len 7 | |
| UBI: usable_leb_size 262016 | |
| UBI: used_ebs 4 | |
| UBI: used_bytes 1048064 | |
| UBI: last_eb_bytes 262016 | |
| UBI: corrupted 0 | |
| UBI: upd_marker 0 | |
| UBI: name testvol | |
| UBI: volume information dump: | |
| UBI: vol_id 2147479551 | |
| UBI: reserved_pebs 2 | |
| UBI: alignment 1 | |
| UBI: data_pad 0 | |
| UBI: vol_type 3 | |
| UBI: name_len 13 | |
| UBI: usable_leb_size 262016 | |
| UBI: used_ebs 2 | |
| UBI: used_bytes 524032 | |
| UBI: last_eb_bytes 2 | |
| UBI: corrupted 0 | |
| UBI: upd_marker 0 | |
| UBI: name layout volume | |
| => ubi info | |
| UBI: MTD device name: "mtd=2" | |
| UBI: MTD device size: 2 MiB | |
| UBI: physical eraseblock size: 262144 bytes (256 KiB) | |
| UBI: logical eraseblock size: 262016 bytes | |
| UBI: number of good PEBs: 8 | |
| UBI: number of bad PEBs: 0 | |
| UBI: smallest flash I/O unit: 1 | |
| UBI: VID header offset: 64 (aligned 64) | |
| UBI: data offset: 128 | |
| UBI: max. allowed volumes: 128 | |
| UBI: wear-leveling threshold: 4096 | |
| UBI: number of internal volumes: 1 | |
| UBI: number of user volumes: 1 | |
| UBI: available PEBs: 0 | |
| UBI: total number of reserved PEBs: 8 | |
| UBI: number of PEBs reserved for bad PEB handling: 0 | |
| UBI: max/mean erase counter: 4/1 | |
| => ubi write 800000 testvol 80000 | |
| Volume "testvol" found at volume id 0 | |
| => ubi read 900000 testvol 80000 | |
| Volume testvol found at volume id 0 | |
| read 524288 bytes from volume 0 to 900000(buf address) | |
| => cmp.b 800000 900000 80000 | |
| Total of 524288 bytes were the same | |
| Next, the ubifsmount command allows you to access filesystems on the | |
| UBI partition which has been attached with the ubi part command: | |
| => help ubifsmount | |
| ubifsmount - mount UBIFS volume | |
| Usage: | |
| ubifsmount <volume-name> | |
| - mount 'volume-name' volume | |
| For example: | |
| => ubifsmount ubi0:recovery | |
| UBIFS: mounted UBI device 0, volume 0, name "recovery" | |
| UBIFS: mounted read-only | |
| UBIFS: file system size: 46473216 bytes (45384 KiB, 44 MiB, 366 LEBs) | |
| UBIFS: journal size: 6348800 bytes (6200 KiB, 6 MiB, 50 LEBs) | |
| UBIFS: media format: w4/r0 (latest is w4/r0) | |
| UBIFS: default compressor: LZO | |
| UBIFS: reserved for root: 0 bytes (0 KiB) | |
| Note that unlike Linux, U-Boot can only have one active UBI partition | |
| at a time, which can be referred to as ubi0, and must be supplied along | |
| with the name of the filesystem you are mounting. | |
| Once a UBI filesystem has been mounted, the ubifsls command allows you | |
| to list the contents of a directory in the filesystem: | |
| => help ubifsls | |
| ubifsls - list files in a directory | |
| Usage: | |
| ubifsls [directory] | |
| - list files in a 'directory' (default '/') | |
| For example: | |
| => ubifsls | |
| 17442 Thu Jan 01 02:57:38 1970 imx28-evk.dtb | |
| 2998146 Thu Jan 01 02:57:43 1970 zImage | |
| And the ubifsload command allows you to load a file from a UBI | |
| filesystem: | |
| => help ubifsload | |
| ubifsload - load file from an UBIFS filesystem | |
| Usage: | |
| ubifsload <addr> <filename> [bytes] | |
| - load file 'filename' to address 'addr' | |
| For example: | |
| => ubifsload ${loadaddr} zImage | |
| Loading file 'zImage' to addr 0x42000000 with size 2998146 (0x002dbf82)... | |
| Done | |
| Finally, you can unmount the UBI filesystem with the ubifsumount | |
| command: | |
| => help ubifsumount | |
| ubifsumount - unmount UBIFS volume | |
| Usage: | |
| ubifsumount - unmount current volume | |
| For example: | |
| => ubifsumount | |
| Unmounting UBIFS volume recovery! | |
| Usage of the UBI CRC skip-check flag of static volumes: | |
| ------------------------------------------------------- | |
| Some users of static UBI volumes implement their own integrity check, | |
| thus making the volume CRC check done at open time useless. For | |
| instance, this is the case when one use the ubiblock + dm-verity + | |
| squashfs combination, where dm-verity already checks integrity of the | |
| block device but this time at the block granularity instead of verifying | |
| the whole volume. | |
| Skipping this test drastically improves the boot-time. | |
| U-Boot now supports the "skip_check" flag to optionally skip the CRC | |
| check at open time. | |
| Usage: Case A - Upon UBI volume creation: | |
| You can optionally add "--skipcheck" to the "ubi create" command: | |
| ubi create[vol] volume [size] [type] [id] [--skipcheck] | |
| - create volume name with size ('-' for maximum available size) | |
| Usage: Case B - With an already existing UBI volume: | |
| Use the "ubi skipcheck" command: | |
| ubi skipcheck volume on/off - Set or clear skip_check flag in volume header | |
| Example: | |
| => ubi skipcheck rootfs0 on | |
| Setting skip_check on volume rootfs0 | |
| BTW: This saves approx. 10 seconds Linux bootup time on a MT7688 based | |
| target with 128MiB of SPI NAND. |