[LinuxBIOS] FILO with the USB

Corey Osgood corey.osgood at gmail.com
Thu Nov 15 07:41:42 CET 2007

Fridel Fainshtein wrote:
> Hello all,
> It seams that the USB code was taken from the previous version of FILO
> but never have been tested.

Since noone else piped up, here's what I've figured out:
Older versions of FILO (<0.5) don't have any USB support. The original
author(s) of FILO's USB stack were from LinuxLabs. I don't know what the
story is, but it was probably written under contract for someone (in a
case where it did work), and they simply don't have the time to provide
support for it. I've heard that it was originally merged from Etherboot,
where it may have worked, but I can't confirm that. In any case, it
doesn't seem to have been really touched since the initial import to the
svn repository, according to the svn logs.

> Some symptoms are
> 1)
> malloc_diag: alloc: 4208 bytes (8 blocks), free: 61320 bytes (1 blocks)
> malloc_check: sizes mismatch: 0xa1 vs 0x0 at 00132670
> 2)
> dma_to_td: can not find td

Is this using an OHCI controller? I've tried several times with UHCI and
seen a different error:

malloc_diag: alloc: xxxx bytes ([x] blocks), free: xxxx bytes (2 blocks)
init_framelist: frame_list is at 13[n]000
dump_link: frame_list_link: addr: 001233[n+1]0
dump_link: frame_list_link:  raw addr: 1bfd40[n*2]0
dump_link: frame_list_link: terminate: 0
dump_link: frame_list_link: queue: 1
dump_link: frame_list_link: depth: 0
(repeated half a dozen or so times)
Out of heap space

> Trying to debug it, I discovered the following piece of code:
> void *allot2(size_t size, unsigned int alignment)
> {
> 	void *addr;
> 	unsigned long addrval;
> 	addr=malloc(2*size);
> 	addrval=(unsigned long)addr;
> 	addrval+=alignment+1; //  0x12345600 + 0xff + 1
> 	addrval&=~alignment;  //  0x12345700
> 	*(void * *)(addrval-sizeof(unsigned long))=addr;
> 	return (void *)addrval;
> }
> void forget2(void *mem)
> {
> 	unsigned long addr=(unsigned long)mem;
> 	addr-=sizeof(unsigned long);
> 	free((void *)(*(unsigned long *)addr));
> }
> I have 2 questions:
> if size = 8 and alignment=256, it writes outside malloc allocation, isn't it?
> What was the meaning of the code?
> Thanks

No idea. This does sound like something worth taking a look at, you
might want to investigate how Etherboot does malloc/allot and also see
if USB really does work there.

Good luck!

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