On 11.02.2014 21:19, Josh Cartwright wrote:
On Tue, Feb 11, 2014 at 09:04:21PM +0100, Tomasz Figa wrote:
On 11.02.2014 21:02, Benjamin Herrenschmidt wrote:
On Tue, 2014-02-11 at 19:01 +0000, Grant Likely wrote:
except that the former IMHO better suits the definition of memory region, which I see as a single contiguous range of memory and can be simplified to have a single reg entry per region.
My point is rather if multiple reg tuples are found in a reserved memory node, the kernel must respect them and reserve the memory. I'm not arguing about whether or not that makes for a good binding.
agreed.
My point is why, if the binding defines that just a single tuple should be provided.
FWIW, the usecase I had mentioned in reply to Grant in the patch 5/5 thread [1] could make use of this. The shared memory region is split into a main chunk and several "auxiliary" chunk, but collectively these regions all share the same heap state.
Josh
1: http://lkml.kernel.org/r/20140205192502.GO20228@joshc.qualcomm.com
The use case seems fine, but I believe it could be properly represented in device tree using multiple single-reg regions as well, unless the consumer can request a block of memory that crosses boundary of two sub-regions specified by reg entries of single region.
Best regards, Tomasz