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@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx>
---
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@xxxxxxxxxx>
To this patch when you submit the driver changes.
Thank you,
---
Best Regards
Kunihiko Hayashi
