Hi,
thank you for your help.
I will read the DMA documentation. But I need to make DMA on User memory
space allocated in user space. Because I don't want the kernel to make
allocation and deallocation during execution for stability.
Best regards.
Sebastien
Arjan van de Ven wrote :
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/
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