Hi John, Thank you for your comment.
On 2020/07/29 4:17, John Stultz wrote:
On Thu, Jul 16, 2020 at 6:10 PM Kunihiko Hayashi hayashi.kunihiko@socionext.com wrote:
Current dma-buf heaps can handle only default CMA. This introduces dma_heap_add_cma() function to attach CMA heaps that belongs to a device.
At first, the driver calls of_reserved_mem_device_init() to set memory-region property associated with reserved-memory defined as CMA to the device. And when the driver calls this dma_heap_add_cma(), the CMA will be added to dma-buf heaps.
For example, prepare CMA node named "linux,cma@10000000" and specify the node for memory-region property. After the above calls in the driver, a device file "/dev/dma_heap/linux,cma@10000000" associated with the CMA become available as dma-buf heaps.
Signed-off-by: Kunihiko Hayashi hayashi.kunihiko@socionext.com
drivers/dma-buf/heaps/cma_heap.c | 12 ++++++++++++ include/linux/dma-heap.h | 9 +++++++++ 2 files changed, 21 insertions(+)
Hey! Sorry for the slow response on this! I just realized I never replied!
I waited but no problem.
diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c index 626cf7f..5d2442e 100644 --- a/drivers/dma-buf/heaps/cma_heap.c +++ b/drivers/dma-buf/heaps/cma_heap.c
[snip]
-- 2.7.4
Looks sane to me. Being able to expose different multiple CMA heaps is needed, and I agree this way (as opposed to my earlier dts appraoch) is probably the best approach. The only bit I'm so-so on is adding the CMA heap specific call in the dma-heap.h, but at the same time I can't justify adding a whole new header for a single function.
I'm also a little worried about whether "CMA specific" call is in the dma-heap.h, however I can't find another solution.
Do you have a upstream driver that you plan to make use this new call?
Unfortunately I don't have an upstream driver using this call.
This call is called from dma-buf heaps "importer" or "customer", and I only made an example (do nothing) importer driver to test the call.
We want to have in-tree users of code added.
I think this is a generic way to use non-default CMA heaps, however, we need in-tree "importer" drivers to want to use non-default CMA heaps. I don't find it from now.
But if so, feel free to add my: Acked-by: John Stultz john.stultz@linaro.org To this patch when you submit the driver changes.
Thank you,
--- Best Regards Kunihiko Hayashi