Re: [PATCH] staging: ion: Add a default struct device for cma heap
From: Michal Nazarewicz
Date: Thu Aug 06 2015 - 07:40:56 EST
On Thu, Aug 06 2015, Feng Tang wrote:
> When trying to use several cma heaps on our platforms,
> we met a memory issue due to that the several cma_heaps
> are sharing the same "struct device *".
>
> As in current code base, the normal cma heap creating
> process is, one platform device is created during boot,
> and it will sequentially create cma heaps (usually passing
> its own struct device * as a parameter)
>
> For the multiple cma heaps case, there will be one "struct
> cma" created for each cma heap, and this "struct cma *" is
> saved in dev->cma_area. So the single platform device can't
> meet the requirement here.
>
> So this patch add one default device for a cma heap to avoid
> sharing the same "struct device", thus fix the issue. And it
> doesn't break existing code by only using that default device
> when no "struct device *" is passed in.
>
> Also, since the cma framework has been cleaned up, this patch
> also add a platform data member to pass the "struct cma*" to
> ion_cma_heap_create().
>
> Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>
>From CMAâs point of view:
Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
> ---
> drivers/staging/android/ion/ion.h | 4 ++++
> drivers/staging/android/ion/ion_cma_heap.c | 20 +++++++++++++++++---
> 2 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/staging/android/ion/ion.h b/drivers/staging/android/ion/ion.h
> index 443db84..e9af17e 100644
> --- a/drivers/staging/android/ion/ion.h
> +++ b/drivers/staging/android/ion/ion.h
> @@ -45,6 +45,9 @@ struct ion_buffer;
> * @size: size of the heap in bytes if applicable
> * @align: required alignment in physical memory if applicable
> * @priv: private info passed from the board file
> + * @priv2: when creating CMA heap, platform device should better also
> + * pass the "struct cma *" info, so that the cma buffer request
> + * know where to go for the buffer
> *
> * Provided by the board file.
> */
> @@ -56,6 +59,7 @@ struct ion_platform_heap {
> size_t size;
> ion_phys_addr_t align;
> void *priv;
> + void *priv2;
Why are those void pointers anyway? Perhaps just make them struct device
*dev and struct cma *cma? Especially since priv2 is a bit awkward name.
> };
>
> /**
> diff --git a/drivers/staging/android/ion/ion_cma_heap.c b/drivers/staging/android/ion/ion_cma_heap.c
> index f4211f1..b3e8896 100644
> --- a/drivers/staging/android/ion/ion_cma_heap.c
> +++ b/drivers/staging/android/ion/ion_cma_heap.c
> @@ -29,6 +29,7 @@
> struct ion_cma_heap {
> struct ion_heap heap;
> struct device *dev;
> + struct device default_dma_dev;
> };
>
> #define to_cma_heap(x) container_of(x, struct ion_cma_heap, heap)
> @@ -180,9 +181,22 @@ struct ion_heap *ion_cma_heap_create(struct ion_platform_heap *data)
> return ERR_PTR(-ENOMEM);
>
> cma_heap->heap.ops = &ion_cma_ops;
> - /* get device from private heaps data, later it will be
> - * used to make the link with reserved CMA memory */
> - cma_heap->dev = data->priv;
> +
> + /*
> + * data->priv for cma heap is currently supposed to point
> + * to a "struct device *"
> + */
> + if (data->priv) {
> + cma_heap->dev = data->priv;
> + } else {
> + cma_heap->dev = &cma_heap->default_dma_dev;
> + cma_heap->dev->coherent_dma_mask = DMA_BIT_MASK(32);
> + cma_heap->dev->dma_mask = &dev->coherent_dma_mask;
> + }
> +
> + /* data->priv2 contains a pointer to struct cma */
> + dev_set_cma_area(cma_heap->dev, data->priv2);
Perhaps:
+ if (data->priv2)
+ dev_set_cma_area(cma_heap->dev, data->priv2);
> +
> cma_heap->heap.type = ION_HEAP_TYPE_DMA;
> return &cma_heap->heap;
> }
> --
> 1.7.9.5
>
--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, MichaÅ âmina86â Nazarewicz (o o)
ooo +--<mpn@xxxxxxxxxx>--<xmpp:mina86@xxxxxxxxxx>--ooO--(_)--Ooo--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/