[PATCH v2 0/7] Add dts for mt8183 GPU (and misc panfrost patches)
steven.price at arm.com
Thu Jan 9 04:01:36 PST 2020
On 08/01/2020 05:23, Nicolas Boichat wrote:
> Sorry for the long delay since https://patchwork.kernel.org/patch/11132381/,
> finally got around to give this a real try.
> The main purpose of this series is to upstream the dts change and the binding
> document, but I wanted to see how far I could probe the GPU, to check that the
> binding is indeed correct. The rest of the patches are RFC/work-in-progress, but
> I think some of them could already be picked up.
> So this is tested on MT8183 with a chromeos-4.19 kernel, and a ton of
> backports to get the latest panfrost driver (I should probably try on
> linux-next at some point but this was the path of least resistance).
> I tested it as a module as it's more challenging (originally probing would
> work built-in, on boot, but not as a module, as I didn't have the power
> domain changes, and all power domains are on by default during boot).
> Probing logs looks like this, currently:
> [ 221.867726] panfrost 13040000.gpu: clock rate = 511999970
> [ 221.867929] panfrost 13040000.gpu: Linked as a consumer to regulator.14
> [ 221.868600] panfrost 13040000.gpu: Linked as a consumer to regulator.31
> [ 221.870586] panfrost 13040000.gpu: Linked as a consumer to genpd:0:13040000.gpu
> [ 221.871492] panfrost 13040000.gpu: Linked as a consumer to genpd:1:13040000.gpu
> [ 221.871866] panfrost 13040000.gpu: Linked as a consumer to genpd:2:13040000.gpu
> [ 221.872427] panfrost 13040000.gpu: mali-g72 id 0x6221 major 0x0 minor 0x3 status 0x0
> [ 221.872439] panfrost 13040000.gpu: features: 00000000,13de77ff, issues: 00000000,00000400
> [ 221.872445] panfrost 13040000.gpu: Features: L2:0x07120206 Shader:0x00000000 Tiler:0x00000809 Mem:0x1 MMU:0x00002830 AS:0xff JS:0x7
> [ 221.872449] panfrost 13040000.gpu: shader_present=0x7 l2_present=0x1
> [ 221.873526] panfrost 13040000.gpu: error powering up gpu stack
> [ 221.878088] [drm] Initialized panfrost 1.1.0 20180908 for 13040000.gpu on minor 2
> [ 221.940817] panfrost 13040000.gpu: error powering up gpu stack
> [ 222.018233] panfrost 13040000.gpu: error powering up gpu stack
It's interesting that it's only the stack that is failing. In hardware there's a dependency: L2->stack->shader - so in theory the shader cores shouldn't be able to power up either. There are some known hardware bugs here though:
"Let the driver power on/off the GPU core stack independently "
"without involving the Power Domain Controller. This should "
"only be enabled on platforms for which integration of the PDC "
"to the Mali GPU is known to be problematic.");
It might be worth just dropping the code for powering up/down stacks and let the GPU's own dependency management handle it.
> So the GPU is probed, but there's an issue when powering up the STACK, not
> quite sure why, I'll try to have a deeper look, at some point.
> - Use sram instead of mali_sram as SRAM supply name.
> - Rename mali@ to gpu at .
> - Add dt-bindings changes
> - Stacking patches after the device tree change that allow basic
> probing (still incomplete and broken).
> Nicolas Boichat (7):
> dt-bindings: gpu: mali-bifrost: Add Mediatek MT8183
> arm64: dts: mt8183: Add node for the Mali GPU
> drm/panfrost: Improve error reporting in panfrost_gpu_power_on
> drm/panfrost: Add support for a second regulator for the GPU
> drm/panfrost: Add support for multiple power domain support
> RFC: drm/panfrost: Add bifrost compatible string
> RFC: drm/panfrost: devfreq: Add support for 2 regulators
> .../bindings/gpu/arm,mali-bifrost.yaml | 20 ++++
> arch/arm64/boot/dts/mediatek/mt8183-evb.dts | 7 ++
> arch/arm64/boot/dts/mediatek/mt8183.dtsi | 104 +++++++++++++++++
> drivers/gpu/drm/panfrost/panfrost_devfreq.c | 18 +++
> drivers/gpu/drm/panfrost/panfrost_device.c | 108 ++++++++++++++++--
> drivers/gpu/drm/panfrost/panfrost_device.h | 7 ++
> drivers/gpu/drm/panfrost/panfrost_drv.c | 1 +
> drivers/gpu/drm/panfrost/panfrost_gpu.c | 15 ++-
> 8 files changed, 267 insertions(+), 13 deletions(-)
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