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!

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 @@ -162,6 +162,18 @@ static int __add_cma_heap(struct cma *cma, void *data) return 0; }

+/* add device CMA heap to dmabuf heaps */ +int dma_heap_add_cma(struct device *dev) +{

•   struct cma *cma = dev_get_cma_area(dev);
  

•   if (!cma)
  

•           return -ENOMEM;
  

•   return __add_cma_heap(cma, NULL);
  

+} +EXPORT_SYMBOL_GPL(dma_heap_add_cma);

static int add_default_cma_heap(void) { struct cma *default_cma = dev_get_cma_area(NULL); diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h index 454e354..16bec7d 100644 --- a/include/linux/dma-heap.h +++ b/include/linux/dma-heap.h @@ -56,4 +56,13 @@ void *dma_heap_get_drvdata(struct dma_heap *heap); */ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info);

+#ifdef CONFIG_DMABUF_HEAPS_CMA +/**

• • dma_heap_add_cma - adds a device CMA heap to dmabuf heaps
• • @dev: device with a CMA heap to register
• */

+int dma_heap_add_cma(struct device *dev);

+#endif /* CONFIG_DMABUF_HEAPS_CMA */

#endif /* _DMA_HEAPS_H */

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.

Do you have a upstream driver that you plan to make use this new call? We want to have in-tree users of code added.

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.

thanks -john