Messages in this thread | | | Subject | Re: [RFC] generic device DMA implementation | From | Miles Bader <> | Date | 05 Dec 2002 11:31:10 +0900 |
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James Bottomley <James.Bottomley@steeleye.com> writes: > > How is the driver supposed to tell whether a given dma_addr_t value > > represents consistent memory or not? It seems like an > > (arch-specific) `dma_addr_is_consistent' function is necessary, but > > I couldn't see one in your patch. > > If you have a machine that has both consistent and inconsistent blocks, you > need to encode that in dma_addr_t (which is a platform definable type). > > The sync functions would just decode the type and either nop or perform the > sync.
My thinking was that a driver might want to do things like --
if (dma_addr_is_consistent (some_funky_addr)) { do it quickly; } else do_it_the_slow_way (some_funky_addr);
in other words, something besides just calling the sync functions, in the case where the memory was consistent.
-Miles -- Suburbia: where they tear out the trees and then name streets after them. - 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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