Messages in this thread | | | Subject | Re: [PATCH] dma-buf: heaps: Introduce dma_heap_add_cma() for non-default CMA heap | From | Kunihiko Hayashi <> | Date | Fri, 31 Jul 2020 18:32:41 +0900 |
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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
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