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SubjectRe: [PATCH] misc: sram: Add dma-heap-export reserved SRAM area type
On Fri, Apr 24, 2020 at 5:27 PM Andrew F. Davis <afd@ti.com> wrote:
>
> This new export type exposes to userspace the SRAM area as a DMA-Heap,
> this allows for allocations as DMA-BUFs that can be consumed by various
> DMA-BUF supporting devices.
>
> Signed-off-by: Andrew F. Davis <afd@ti.com>
> ---
> .../devicetree/bindings/sram/sram.yaml | 8 +

Separate patch and needs to go to DT list...

> drivers/misc/Kconfig | 7 +
> drivers/misc/Makefile | 1 +
> drivers/misc/sram-dma-heap.c | 243 ++++++++++++++++++
> drivers/misc/sram.c | 20 +-
> drivers/misc/sram.h | 17 ++
> 6 files changed, 292 insertions(+), 4 deletions(-)
> create mode 100644 drivers/misc/sram-dma-heap.c
>
> diff --git a/Documentation/devicetree/bindings/sram/sram.yaml b/Documentation/devicetree/bindings/sram/sram.yaml
> index 7b83cc6c9bfa..b8e33c8d205d 100644
> --- a/Documentation/devicetree/bindings/sram/sram.yaml
> +++ b/Documentation/devicetree/bindings/sram/sram.yaml
> @@ -105,6 +105,14 @@ patternProperties:
> manipulation of the page attributes.
> type: boolean
>
> + dma-heap-export:
> + description:
> + Similar to 'pool' and 'export' this region will be exported for use
> + by drivers, devices, and userspace using the DMA-Heaps framework.
> + NOTE: This region must be page aligned on start and end in order to
> + properly allow manipulation of the page attributes.
> + type: boolean

Though I'm not sure this should be in DT. You have to change your
firmware to enable a new kernel feature? We also already have 'export'
which sounds like the same function. Or 'pool' though reading the
description, I don't really understand it's use.

What combination of all 3 of these options would be valid?

Rob

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