[lkml]   [2005]   [Nov]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: DMA transfer with kiobuf, kernel 2.4.21
On Tue, 2005-11-15 at 18:53 +0100, sej wrote:
> > that sounds the wrong approach.. why don't you make your device driver
> > export an mmap function.. and let the userspace app use that ?
> I can't because I need to allocate 128MB of memory per PCI card and if I put for example 4 cards, I'll have 512MB in kernel memory, and I think there will be some problem in kernel.

no there isn't.. there is no rule that memory you allocate for this as
to be lowmem... at all.

> >transfer->Descript[i].size = PAGE_SIZE;
> >transfer->Descript[i].pciaddr = (ULONG)
> >virt_to_phys(page_address(iobuf->maplist[idxIobuf]));
> >
> >
> > you really need to use the PCI DMA mapping api!
> I have a plx bridge PCI9656 with a DMA controler. So I have to make a
> descriptor table with physical address and size.
> I work in 32 bits address mode, but I don't know which function to call
> to get a 36bits address for my controler.

see the PCI DMA mapping api. the docs for it are in Documentation/

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-11-15 19:04    [W:0.051 / U:4.800 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site