24 Jun
2013
24 Jun
'13
7:21 a.m.
On Mon, Jun 24, 2013 at 08:17:59AM +0300, Hiroshi Doyu wrote:
Ok, thanks. One more question, IOMMU H/W sometimes supports more platform specific attributes than READ/WRITE. For example, in OMAP,
#define IOMMU_FLAG (IOVMF_ENDIAN_LITTLE | IOVMF_ELSZ_8)
Is there any way to deal with those platform specific attrs from DMA mapping API POV?
Depends on the kind of flag and whether you want to make it changeable from the DMA-API. The AMD IOMMU for example has a flag in the page-tables to force PCI DMA coherency. This is always set by the driver.
For other parameters that should be changeable and don't fit into the dma_direction parameter in some way the use of dma_attr would make sense.
Joerg