From: Christoph Hellwig <hch@xxxxxxxxxxxxx> Sent: Monday, January 14, 2019 5:53 PM > On Fri, Jan 11, 2019 at 01:28:46AM +0000, Andy Duan wrote: > > As NXP i.MX8 platform requirement that M4 only access the fixed memory > > region, so do You have any suggestion to fix the issue and satisfy the > > requirement ? Or do you have plan To fix the root cause ? > > I think the answer is to use RESERVEDMEM_OF_DECLARE without the DMA > coherent boilerplate code. If use RESERVEDMEM_OF_DECLARE with DMA contiguous code (CMA), it can match the requirement, but as you know, the CMA size alignment is 32M bytes, we only need 8M bytes contiguous mem for rpmsg. > > For the initial prototype just do it inside the driver, although I'd like to > eventually factor this out into common code, especially if my proposal for > more general availability of DMA_ATTR_NON_CONSISTENT goes ahead.
