dma_alloc_coherent() on PPC32: physical addresses above 2G possible?
From: Stefan Richter
Date: Sun Jul 20 2008 - 14:36:43 EST
Hi all,
I have to implement a workaround for a PCI device which gets into
trouble if descriptors are located at 32bit addresses, while 31bit
addresses are fine. I would like to avoid this workaround on machines
on which dma_alloc_coherent() won't ever go at memory above 2 GB.
Is defined(CONFIG_PPC32) a safe test for this? I'm under the impression
that defined(CONFIG_X86_32) is safe.
Are there any other means to detect when the workaround can be omitted,
at compile time or at runtime?
PS: I don't want to set the DMA mask of this device to DMA_31BIT_MASK
because that would be detrimental to other functions of the device. It's
a TI TSB43AB22A FireWire controller.
--
Stefan Richter
-=====-==--- -=== =-=--
http://arcgraph.de/sr/
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