[Yaffs-archive] YAFFS checkin & update

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Author: Charles Manning
Date:  
To: yaffs
Subject: [Yaffs-archive] YAFFS checkin & update
Hi yaffsers

It must be getting to spring in New Zealand. Our Romney ewe birthed twins
last night. Everyone doing well.

On the third attempt I finally got my internet connection good enough to get
CVS going. I have checked in the following:
Bug fixes:
* Changes to fix some bugs that were causing incorrect data look-up in the
file lookup trees.
* Improved scanning (previous scanner seemed to get some stuff wrong).
* Some general clean-up.

Enhancements:
* Changes to improve reporting of ecc failures.
* Add support for special files (pipes, devices). Critical for use as a root
fs.
* Added utility called mkyaffsimage. This will build a yaffs image from a
directory tree on the host. Useful for building root file systems.

Over the last wee while I have ported YAFFS to run uder WinCE. The guts only
required minor tweaks to make this happen. Most of the work was in the FSD
layer (the part that hooks up to the file system manager). If this project
comes to fruition (which I expect), then all the related code will GPLed. The
bootloader (which does not use the core yaffs code) will be LGPLed - which I
believe makes it easier to integrate. Stephen Hill (the author of nand_ecc.c
- the only code I use in the bootloader) has agreed to licensing changes to
support this effort.

I can no longer reproduce the "directory problem" with the code as checked
in. Nick, can you plz have a go and tell me what you see. Thanx.

Having now done 3 WinCE platformn implementations I have a good reason to
hate WinCE. I do get a good feeling being able to use my time in a way that
aids YAFFS. This effort has assisted in flushing out some bugs and has
provided some ideas for future improvements.

YAFFS runs sweetly on the WinCE device. Boots no faster that the FAT-based
stuff (due to the scanning overhead at start up). However once running, YAFFS
goes like a cut cat. 1MB/s write speed with no obvious slowdowns due to
garbage collection.

I ran the some file stress tests over the weekend on a 128MB NAND array (2x64
Samsung parts) + StrongARM + WInCE. 25GB wriiten, verified thrice, then
deleted. No performance degradation observed. Not one bit corrupted.

A second unit has had its NAND badly mauled - including having its bad block
markers erased. This ran YAFFS quite well, though some data was corrupted due
to "write disturb". This clearly underlines the importance of not erasing the
bad block info.


Enjoy.

Feedback more than welcome.

-- Charles


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