dma_alloc_from_coherent

[Gang Lei (雷刚)]

HI:

Can anybody point out that from which pool that function will allocate coherent memory for DMA use?
I checked the function source code, the comments is as follow:

This function should be only called from per-arch dma_alloc_coherent()
* to support allocation from per-device coherent memory pools.
*
* Returns 0 if dma_alloc_coherent should continue with allocating from
* generic memory areas, or !0 if dma_alloc_coherent should return @ret.


Can anyone elaborate it? What’s per-device coherent memory pools, when are those pools setup and how?


Thanks a lot!


Rick lei

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