Re: [PATCH v1 00/29] Introduce memory interconnect for NVIDIA Tegra SoCs

From: Thierry Reding <thierry.reding@gmail.com>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: devicetree@vger.kernel.org, linux-pm@vger.kernel.org,
	Peter De Schrijver <pdeschrijver@nvidia.com>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	Mikko Perttunen <mperttunen@nvidia.com>,
	Rob Herring <robh+dt@kernel.org>,
	linux-tegra@vger.kernel.org,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Georgi Djakov <georgi.djakov@linaro.org>
Subject: Re: [PATCH v1 00/29] Introduce memory interconnect for NVIDIA Tegra SoCs
Date: Tue, 19 Nov 2019 07:19:31 +0100	[thread overview]
Message-ID: <20191119061931.GA2462695@ulmo> (raw)
In-Reply-To: <20191118200247.3567-1-digetx@gmail.com>

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On Mon, Nov 18, 2019 at 11:02:18PM +0300, Dmitry Osipenko wrote:
> Hello,
> 

I like this, thanks for looking into this.

> This series brings initial support for memory interconnect to Tegra20,
> Terga30 and Tegra124 SoCs. The interconnect provides are quite generic
> and should be suitable for all Tegra SoCs, but currently upstream kernel
> has EMC/MC drivers only for those three generations of Tegra SoCs.

Tegra186 and Tegra194 should support this out of the box because the EMC
frequency can be scaled via the BPMP. Tegra210 support for EMC scaling
is in the works, so hopefully we'll be able to extend this in the near
future.

> For the start only display controllers are getting interconnect API
> support, others could be supported later on. The display controllers
> have the biggest demand for interconnect API right now because dynamic
> memory frequency scaling can't be done safely without taking into account
> bandwidth requirement from the displays.

Agreed, display controllers are where we most immediately notice when
there's not enough bandwidth. I think it's fair to start small and
extend interconnect consumers as we progress.

I've got a couple of comments regarding individual patches, but on the
whole this looks pretty nice.

Thierry

> Dmitry Osipenko (29):
>   dt-bindings: memory: tegra20: mc: Document new interconnect property
>   dt-bindings: memory: tegra20: emc: Document new interconnect property
>   dt-bindings: memory: tegra30: mc: Document new interconnect property
>   dt-bindings: memory: tegra30: emc: Document new interconnect property
>   dt-bindings: memory: tegra124: mc: Document new interconnect property
>   dt-bindings: memory: tegra124: emc: Document new interconnect property
>   dt-bindings: host1x: Document new interconnect properties
>   dt-bindings: interconnect: tegra: Add initial IDs
>   ARM: tegra: Add interconnect properties to Tegra20 device-tree
>   ARM: tegra: Add interconnect properties to Tegra30 device-tree
>   ARM: tegra: Add interconnect properties to Tegra124 device-tree
>   interconnect: Add memory interconnection providers for NVIDIA Tegra
>     SoCs
>   memory: tegra: Register as interconnect provider
>   memory: tegra: Add interconnect nodes for Terga20 display controllers
>   memory: tegra: Add interconnect nodes for Terga30 display controllers
>   memory: tegra: Add interconnect nodes for Terga124 display controllers
>   memory: tegra20-emc: Use devm_platform_ioremap_resource
>   memory: tegra20-emc: Continue probing if timings/IRQ are missing in
>     device-tree
>   memory: tegra20-emc: Register as interconnect provider
>   memory: tegra30-emc: Continue probing if timings are missing in
>     device-tree
>   memory: tegra30-emc: Register as interconnect provider
>   memory: tegra124-emc: Use devm_platform_ioremap_resource
>   memory: tegra124-emc: Register as interconnect provider
>   drm/tegra: dc: Use devm_platform_ioremap_resource
>   drm/tegra: dc: Release PM and RGB output when client's registration
>     fails
>   drm/tegra: dc: Support memory bandwidth management
>   ARM: tegra: Enable interconnect API in tegra_defconfig
>   ARM: multi_v7_defconfig: Enable NVIDIA Tegra interconnect providers
>   MAINTAINERS: Add maintainers for NVIDIA Tegra interconnect drivers
> 
>  .../display/tegra/nvidia,tegra20-host1x.txt   |  67 +++++
>  .../nvidia,tegra124-emc.txt                   |   3 +
>  .../nvidia,tegra124-mc.yaml                   |   5 +
>  .../memory-controllers/nvidia,tegra20-emc.txt |   4 +
>  .../memory-controllers/nvidia,tegra20-mc.txt  |   4 +
>  .../nvidia,tegra30-emc.yaml                   |   6 +
>  .../memory-controllers/nvidia,tegra30-mc.yaml |   5 +
>  MAINTAINERS                                   |   9 +
>  arch/arm/boot/dts/tegra124.dtsi               |  10 +
>  arch/arm/boot/dts/tegra20.dtsi                |  11 +-
>  arch/arm/boot/dts/tegra30.dtsi                |  12 +-
>  arch/arm/configs/multi_v7_defconfig           |   2 +
>  arch/arm/configs/tegra_defconfig              |   2 +
>  drivers/gpu/drm/tegra/dc.c                    | 252 +++++++++++++++++-
>  drivers/gpu/drm/tegra/dc.h                    |   8 +
>  drivers/gpu/drm/tegra/drm.c                   |  18 ++
>  drivers/gpu/drm/tegra/plane.c                 |   1 +
>  drivers/gpu/drm/tegra/plane.h                 |   4 +-
>  drivers/interconnect/Kconfig                  |   1 +
>  drivers/interconnect/Makefile                 |   1 +
>  drivers/interconnect/tegra/Kconfig            |   6 +
>  drivers/interconnect/tegra/Makefile           |   4 +
>  drivers/interconnect/tegra/tegra-icc-emc.c    | 138 ++++++++++
>  drivers/interconnect/tegra/tegra-icc-mc.c     | 130 +++++++++
>  drivers/memory/tegra/mc.c                     |   4 +
>  drivers/memory/tegra/tegra124-emc.c           |  28 +-
>  drivers/memory/tegra/tegra124.c               |  16 ++
>  drivers/memory/tegra/tegra20-emc.c            |  91 ++++---
>  drivers/memory/tegra/tegra20.c                |  14 +
>  drivers/memory/tegra/tegra30-emc.c            |  34 ++-
>  drivers/memory/tegra/tegra30.c                |  14 +
>  include/dt-bindings/interconnect/tegra-icc.h  |  11 +
>  include/soc/tegra/mc.h                        |  26 ++
>  33 files changed, 883 insertions(+), 58 deletions(-)
>  create mode 100644 drivers/interconnect/tegra/Kconfig
>  create mode 100644 drivers/interconnect/tegra/Makefile
>  create mode 100644 drivers/interconnect/tegra/tegra-icc-emc.c
>  create mode 100644 drivers/interconnect/tegra/tegra-icc-mc.c
>  create mode 100644 include/dt-bindings/interconnect/tegra-icc.h
> 
> -- 
> 2.23.0
> 

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