Messages in this thread | | | Date | Tue, 24 Sep 2002 11:25:19 -0700 | From | Dave Olien <> | Subject | Re: DAC960 in 2.5.38, with new changes |
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Ok, thanks for explaining!
At some point, I want to step back and look over the BIO and DMA code. Possibly this will be my "project" for October :-)
On Tue, Sep 24, 2002 at 11:21:45AM -0700, David Mosberger wrote: > >>>>> On Tue, 24 Sep 2002 10:28:43 -0700, Dave Olien <dmo@osdl.org> said: > > Dave> Hmm, interesting. A big part of what I'm doing to the driver > Dave> right now is plugging in calls to the PCI DMA interfaces. > > That's fine (actually, it's more than that: it's great!). > > Dave> So unless the underlying implementation is aware of these > Dave> platform limitations and "doing the right thing", I'm adding > Dave> a bunch of bounce buffer activity for many ia64 platforms. > Dave> That would be too bad. > > The idea is to do something along these lines: > > o Use PCA DMA interface for managing all DMA buffers. > > o If sizeof(dma_addr_t) > 4, turn on DAC mode and call > pci_set_dma_mask(dev, MAX_ADDR), where MAX_ADDR is the maximum > address that can be reached by the controller (i.e., > 0xffffffffffffffff for a truly 64-bit-capable PCI controller). > > This way, everything should work out correctly and with good > performance on all imaginable platforms (ia64 with and without > hardware I/O TLB, plain x86, x86 with >4GB RAM, SPARC64 with 32-bit > dma_addr_t, etc.). > > --david - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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