mirror of
https://github.com/AsahiLinux/u-boot
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e6661cf767
U-Boot now supports the "skip_check" flag to optionally skip the CRC check at open time. Currently its only possible to set this bit upon UBI volume creation. But it might be very useful to also set this bit on already installed systems (e.g. field upgrade) to make also use of the boot-time decrease on those systems. This patch now adds a new "ubi" command "ubi skipcheck" to set or clear this bit in the UBI volume header: => 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. Signed-off-by: Stefan Roese <sr@denx.de> Reviewed-by: Heiko Schocher <hs@denx.de> Cc: Quentin Schulz <quentin.schulz@bootlin.com> Cc: Boris Brezillon <boris.brezillon@collabora.com> Cc: Heiko Schocher <hs@denx.de> Cc: Andreas Dannenberg <dannenberg@ti.com>
258 lines
7.7 KiB
Text
258 lines
7.7 KiB
Text
-------------------
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UBI usage in U-Boot
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-------------------
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UBI support in U-Boot is broken down into five separate commands.
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The first is the ubi command, which has six subcommands:
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=> help ubi
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ubi - ubi commands
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Usage:
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ubi part [part] [offset]
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- Show or set current partition (with optional VID header offset)
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ubi info [l[ayout]] - Display volume and ubi layout information
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ubi create[vol] volume [size] [type] - create volume name with size
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ubi write[vol] address volume size - Write volume from address with size
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ubi write.part address volume size [fullsize]
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- Write part of a volume from address
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ubi read[vol] address volume [size] - Read volume to address with size
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ubi remove[vol] volume - Remove volume
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[Legends]
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volume: character name
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size: specified in bytes
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type: s[tatic] or d[ynamic] (default=dynamic)
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The first command that is needed to be issues is "ubi part" to connect
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one mtd partition to the UBI subsystem. This command will either create
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a new UBI device on the requested MTD partition. Or it will attach a
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previously created UBI device. The other UBI commands will only work
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when such a UBI device is attached (via "ubi part"). Here an example:
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=> mtdparts
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device nor0 <1fc000000.nor_flash>, # parts = 6
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#: name size offset mask_flags
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0: kernel 0x00200000 0x00000000 0
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1: dtb 0x00040000 0x00200000 0
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2: root 0x00200000 0x00240000 0
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3: user 0x01ac0000 0x00440000 0
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4: env 0x00080000 0x01f00000 0
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5: u-boot 0x00080000 0x01f80000 0
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active partition: nor0,0 - (kernel) 0x00200000 @ 0x00000000
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defaults:
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mtdids : nor0=1fc000000.nor_flash
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mtdparts: mtdparts=1fc000000.nor_flash:2m(kernel),256k(dtb),2m(root),27392k(user),512k(env),512k(u-boot)
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=> ubi part root
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Creating 1 MTD partitions on "nor0":
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0x000000240000-0x000000440000 : "mtd=2"
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UBI: attaching mtd1 to ubi0
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UBI: physical eraseblock size: 262144 bytes (256 KiB)
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UBI: logical eraseblock size: 262016 bytes
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UBI: smallest flash I/O unit: 1
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UBI: VID header offset: 64 (aligned 64)
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UBI: data offset: 128
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UBI: attached mtd1 to ubi0
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UBI: MTD device name: "mtd=2"
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UBI: MTD device size: 2 MiB
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UBI: number of good PEBs: 8
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UBI: number of bad PEBs: 0
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UBI: max. allowed volumes: 128
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UBI: wear-leveling threshold: 4096
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UBI: number of internal volumes: 1
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UBI: number of user volumes: 1
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UBI: available PEBs: 0
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UBI: total number of reserved PEBs: 8
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UBI: number of PEBs reserved for bad PEB handling: 0
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UBI: max/mean erase counter: 2/1
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Now that the UBI device is attached, this device can be modified
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using the following commands:
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ubi info Display volume and ubi layout information
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ubi createvol Create UBI volume on UBI device
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ubi removevol Remove UBI volume from UBI device
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ubi read Read data from UBI volume to memory
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ubi write Write data from memory to UBI volume
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ubi write.part Write data from memory to UBI volume, in parts
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Here a few examples on the usage:
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=> ubi create testvol
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Creating dynamic volume testvol of size 1048064
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=> ubi info l
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UBI: volume information dump:
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UBI: vol_id 0
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UBI: reserved_pebs 4
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UBI: alignment 1
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UBI: data_pad 0
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UBI: vol_type 3
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UBI: name_len 7
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UBI: usable_leb_size 262016
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UBI: used_ebs 4
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UBI: used_bytes 1048064
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UBI: last_eb_bytes 262016
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UBI: corrupted 0
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UBI: upd_marker 0
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UBI: name testvol
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UBI: volume information dump:
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UBI: vol_id 2147479551
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UBI: reserved_pebs 2
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UBI: alignment 1
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UBI: data_pad 0
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UBI: vol_type 3
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UBI: name_len 13
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UBI: usable_leb_size 262016
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UBI: used_ebs 2
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UBI: used_bytes 524032
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UBI: last_eb_bytes 2
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UBI: corrupted 0
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UBI: upd_marker 0
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UBI: name layout volume
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=> ubi info
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UBI: MTD device name: "mtd=2"
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UBI: MTD device size: 2 MiB
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UBI: physical eraseblock size: 262144 bytes (256 KiB)
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UBI: logical eraseblock size: 262016 bytes
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UBI: number of good PEBs: 8
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UBI: number of bad PEBs: 0
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UBI: smallest flash I/O unit: 1
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UBI: VID header offset: 64 (aligned 64)
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UBI: data offset: 128
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UBI: max. allowed volumes: 128
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UBI: wear-leveling threshold: 4096
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UBI: number of internal volumes: 1
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UBI: number of user volumes: 1
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UBI: available PEBs: 0
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UBI: total number of reserved PEBs: 8
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UBI: number of PEBs reserved for bad PEB handling: 0
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UBI: max/mean erase counter: 4/1
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=> ubi write 800000 testvol 80000
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Volume "testvol" found at volume id 0
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=> ubi read 900000 testvol 80000
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Volume testvol found at volume id 0
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read 524288 bytes from volume 0 to 900000(buf address)
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=> cmp.b 800000 900000 80000
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Total of 524288 bytes were the same
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Next, the ubifsmount command allows you to access filesystems on the
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UBI partition which has been attached with the ubi part command:
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=> help ubifsmount
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ubifsmount - mount UBIFS volume
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Usage:
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ubifsmount <volume-name>
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- mount 'volume-name' volume
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For example:
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=> ubifsmount ubi0:recovery
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UBIFS: mounted UBI device 0, volume 0, name "recovery"
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UBIFS: mounted read-only
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UBIFS: file system size: 46473216 bytes (45384 KiB, 44 MiB, 366 LEBs)
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UBIFS: journal size: 6348800 bytes (6200 KiB, 6 MiB, 50 LEBs)
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UBIFS: media format: w4/r0 (latest is w4/r0)
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UBIFS: default compressor: LZO
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UBIFS: reserved for root: 0 bytes (0 KiB)
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Note that unlike Linux, U-Boot can only have one active UBI partition
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at a time, which can be referred to as ubi0, and must be supplied along
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with the name of the filesystem you are mounting.
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Once a UBI filesystem has been mounted, the ubifsls command allows you
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to list the contents of a directory in the filesystem:
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=> help ubifsls
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ubifsls - list files in a directory
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Usage:
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ubifsls [directory]
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- list files in a 'directory' (default '/')
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For example:
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=> ubifsls
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17442 Thu Jan 01 02:57:38 1970 imx28-evk.dtb
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2998146 Thu Jan 01 02:57:43 1970 zImage
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And the ubifsload command allows you to load a file from a UBI
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filesystem:
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=> help ubifsload
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ubifsload - load file from an UBIFS filesystem
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Usage:
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ubifsload <addr> <filename> [bytes]
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- load file 'filename' to address 'addr'
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For example:
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=> ubifsload ${loadaddr} zImage
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Loading file 'zImage' to addr 0x42000000 with size 2998146 (0x002dbf82)...
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Done
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Finally, you can unmount the UBI filesystem with the ubifsumount
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command:
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=> help ubifsumount
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ubifsumount - unmount UBIFS volume
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Usage:
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ubifsumount - unmount current volume
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For example:
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=> ubifsumount
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Unmounting UBIFS volume recovery!
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Usage of the UBI CRC skip-check flag of static volumes:
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-------------------------------------------------------
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Some users of static UBI volumes implement their own integrity check,
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thus making the volume CRC check done at open time useless. For
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instance, this is the case when one use the ubiblock + dm-verity +
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squashfs combination, where dm-verity already checks integrity of the
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block device but this time at the block granularity instead of verifying
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the whole volume.
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Skipping this test drastically improves the boot-time.
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U-Boot now supports the "skip_check" flag to optionally skip the CRC
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check at open time.
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Usage: Case A - Upon UBI volume creation:
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You can optionally add "--skipcheck" to the "ubi create" command:
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ubi create[vol] volume [size] [type] [id] [--skipcheck]
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- create volume name with size ('-' for maximum available size)
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Usage: Case B - With an already existing UBI volume:
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Use the "ubi skipcheck" command:
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ubi skipcheck volume on/off - Set or clear skip_check flag in volume header
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Example:
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=> ubi skipcheck rootfs0 on
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Setting skip_check on volume rootfs0
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BTW: This saves approx. 10 seconds Linux bootup time on a MT7688 based
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target with 128MiB of SPI NAND.
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