OFW loads Linux from CaFe NAND FLASH / JFFS2

[Mitch Bradley]

It's down to 4.9 seconds now.  I tightened up the DMA read routine a bit.

Mitch Bradley wrote:
> I got the CaFe NAND FLASH driver and jffs2 reader integrated into Open 
> Firmware.
>
> OFW mounted the jffs2 filesystem (the build 91 image, with summary 
> nodes) and loaded /boot/vmlinuz in just under 6 seconds.
>
> That's using DMA access to the CaFe NAND controller.  Programmed I/O 
> takes about twice as long.
>
> OFW doesn't have support for writing individual files to jffs2, but it 
> can copy verbatim filesystem images onto the NAND FLASH..  That's how 
> I got jffs2 onto the FLASH; I copied the distribution image to an 
> ordinary file on a USB key (right out of the box, with the factory FAT 
> filesystem), and told OFW to splat that file onto the NAND FLASH.  The 
> NAND copy methods knows about the factory bad block list and skip 
> around the bad ones.
>
> The JFFS2 file system reader code adds approximate 3400 bytes to OFW's 
> ROM footprint.  It supports node processing  both with and without 
> summaries, file reading with zlib decompression as necessary, path 
> processing, symlinks, and directory listing.
>
> The zlib decompressor size is not included in that footprint size, 
> because it is already present in OFW for other reasons.
>
> The CaFe NAND driver's ROM footprint is 1800 bytes.
>
>
>
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