Hello, On Friday, July 29, 2011 11:36 AM Joerg Roedel wrote: > On Fri, Jul 29, 2011 at 09:50:32AM +0200, Marek Szyprowski wrote: > > On Thursday, July 28, 2011 11:10 PM Ramirez Luna, Omar wrote: > > > > 2. tidspbridge driver sometimes needs to map a physical address into a > > > fixed virtual address (i.e. the start of a firmware section is expected to > > > be at dsp va 0x20000000), there is no straight forward way to do this with > > > the dma api given that it only expects to receive a cpu_addr, a sg or a > > > page, by adding iov_address I could pass phys and iov addresses in a sg > > > and overcome this limitation, but, these addresses belong to: > > > > We also encountered the problem of fixed firmware address. We addressed is by > > setting io address space start to this address and letting device driver to > > rely on the fact that the first call to dma_alloc() will match this address. > > This sounds rather hacky. How about partitioning the address space for > the device and give the dma-api only a part of it. The other parts can > be directly mapped using the iommu-api then. Well, I'm not convinced that iommu-api should be used by the device drivers directly. If possible we should rather extend dma-mapping than use such hacks. Best regards -- Marek Szyprowski Samsung Poland R&D Center -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>