Messages in this thread | | | Date | Wed, 19 Sep 2012 20:21:40 -0600 | From | Stephen Warren <> | Subject | Re: [RFC 0/5] ARM: dma-mapping: New dma_map_ops to control IOVA more precisely |
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On 09/19/2012 07:44 PM, Krishna Reddy wrote: >> When a device driver would only use the IOMMU-API and needs small DMA- >> able areas it has to re-implement something like the DMA-API (basically an >> address allocator) for that. So I don't see a reason why both can't be used in a >> device driver. > > On Tegra, the following use cases need specific IOVA mapping. > 1. Few MMIO blocks need IOVA=PA mapping setup.
In that case, why would we enable the IOMMU for that one device; IOMMU disabled means VA==PA, right? Perhaps isolation of the device so it can only access certain PA ranges for security?
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