Re: help:a issue about arm64 dma coherent Re: Is this patch included in LSK April release

On Wed, May 07, 2014 at 09:38:57AM +0000, Panshilin (Peter) wrote:

we use arm64 dma_alloc_coherent to get a expected non-cacheable buffer. but when we use the buffer as a dma memory for device, after cpu write datas to the buffer, It is not coherent in ddr so that device cann't get proper datas. so we find the LSK current version's dma alloc is malfunctional.

we have to flushcacheall after cpu write datas and It is ok. It shows that dma_alloc_coherent doesn't work properly.

Yes, this is the case. The code in mainline didn't work at the time the last release was made and as only models were available for testing this code could not be verified in LSK at that time. This should be resolved in the 14.05 release.