Re: [RFC, v3 9/9] media: platform: Add Mediatek ISP P1 shared memory device

Tomasz Figa
2019-07-26T07:42:36Z

On Fri, Jul 26, 2019 at 4:41 PM Christoph Hellwig <hch@infradead.org> wrote:
>
> On Fri, Jul 26, 2019 at 02:15:14PM +0900, Tomasz Figa wrote:
> > Could you try dma_get_sgtable() with the SCP struct device and then
> > dma_map_sg() with the P1 struct device?
>
> Please don't do that. dma_get_sgtable is a pretty broken API (see
> the common near the arm implementation) and we should not add more
> users of it. If you want a piece of memory that can be mapped to
> multiple devices allocate it using alloc_pages and then just map
> it to each device.

Thanks for taking a look at this thread.

Unfortunately that wouldn't work. We have a specific reserved memory
pool that is the only memory area accessible to one of the devices.
Any idea how to handle this?

Best regards,
Tomasz