[PATCH 0/6] drm/simpledrm: Support system memory framebuffers

[Thierry Reding]

From: Thierry Reding <treding at nvidia.com>

Hi,

this series of patches adds support for framebuffers residing in system
memory to the simple-framebuffer DRM driver. To do this, the DT bindings
are extended do accept the memory-region property in addition to the reg
property for specifying the framebuffer memory. This is done because the
framebuffer memory will typically also need to be marked as reserved so
that the operating system will not reuse it and the memory-region
property is the standard property to reference reserved memory regions.

A new compatible string is documented to annotate the framebuffer memory
regions and the simpledrm driver has code added to bind such annotated
regions to the simple-framebuffer device.

The second half of the series then adds support for the AB24 format and
ties it all together to provide a simple-framebuffer on Jetson Xavier
NX. It should be noted, though, that the Jetson Xavier NX device tree
nodes are an example only and ultimately these will be generated (or at
least filled in) at runtime because of the variable nature of the values
that they contain.

This example also uses (but doesn't depend on) the iommu-addresses
property that has been proposed and which will hopefully be merged soon.

Thierry

Thierry Reding (6):
  dt-bindings: display: simple-framebuffer: Support system memory
    framebuffers
  dt-bindings: reserved-memory: Support framebuffer reserved memory
  drm/simpledrm: Add support for system memory framebuffers
  drm/format-helper: Support the AB24 format
  drm/simpledrm: Support the AB24 format
  arm64: tegra: Add simple framebuffer on Jetson Xavier NX

 .../bindings/display/simple-framebuffer.yaml  |   5 +
 .../bindings/reserved-memory/framebuffer.yaml |  46 +++++
 .../nvidia/tegra194-p3509-0000+p3668-0001.dts |  32 ++++
 arch/arm64/boot/dts/nvidia/tegra194.dtsi      |   2 +-
 drivers/gpu/drm/drm_format_helper.c           |  35 ++++
 drivers/gpu/drm/tiny/simpledrm.c              | 167 ++++++++++++++----
 6 files changed, 255 insertions(+), 32 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/reserved-memory/framebuffer.yaml

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2.37.2