SPL: Lightweight UBI and UBI fastmap support
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| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 2/2 | spl: Lightweight UBI and UBI fastmap support | +0 | 0 replies |
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Cover letter [U-Boot] [patch 0/2] SPL: Lightweight UBI and UBI fastmap support
Hello Thomas,
Am 05.07.2014 11:48, schrieb Thomas Gleixner:
Quoted 10 lines
Utilizing NAND FLASH requires proper wear leveling and bitflip management. Linux choice for this is UBI. The upstream UBI implementation is far too big for a SPL, but it is desired to load arbitrary payload including u-boot itself from a UBI managed NAND FLASH. That restricts the non-UBI managed part of the NAND flash to the first few eraseblocks which are reserved for the SoC boot ROM to load the SPL.
The following patches provide a lightweight and fast UBI attach and load code, which supports fastmap and full scan mode.
Thnaks for your work. I try to look into this patches ASAP...
Quoted 4 lines
The text foot print on the board which I used for development is:
6854 0 0 6854 1abd
drivers/mtd/ubispl/built-in.o
Quoted 8 lines
Attaching a NAND chip with 4096 physical eraseblocks (4 blocks are reserved for the SPL) takes:
In full scan mode: 1172ms
In fastmap mode: 95msWith that and a moderate sized kernel image, I'm able to hand off to the kernel within less than 500ms.
Great!
Quoted 10 lines
The scan and logical to physical block mapping code is developed from scratch, while the fastmap functions are lifted from the linux kernel source and adjusted to fit the SPL needs.
The implementation is paranoid and carefully preserves the UBI robustness.
For now I keep a private copy of
ubi-media.hwhich should be shared with thedrivers/mtd/ubi/one once Heiko has synced it to the 3.14 source.
Yes, that was also my first thought, as I looked roughly over your patches.
Quoted 6 lines
There is room for more boot time optimizations:
- Implement sub page reads for
nand_spl_simple- Hand the UBI data from SPL to kernel to avoid rescan of the fastmap/flash
bye,
Heiko
Signature · 2 lines
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany