RE: [Linux-ia64] RE: DMA memory limitation?

[Matt_Domsch@Dell.com]

> My device has the limitation that the command buffers I send 
> must be in 32
> bit space, but the IO can be in 64 bit.  But there is only 
> ONE dma_mask for the device.

Ahh, yes.  The AMI MegaRAID driver/controllers have the same requirements.
megaraid solved it as:

pci_find_device() finds their device, they get a pci_dev back which has a
32-bit dma_mask.
pci_alloc_consistent() the mailbox (this must be in 32-bit space).
if it's a 64-bit-capable controller, set pci_dev->dma_mask = ~0L.
pci_alloc_consistent() the command buffers and scatter-gather lists (these
can be in 64-bit space).

Could something similar work for you?

Thanks,
Matt

--
Matt Domsch
Sr. Software Engineer
Dell Linux Solutions
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