linux-kernel - [PATCH v2 00/10] Add PCIe Bandwidth Controller

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Date:   Fri, 15 Sep 2023 15:01:32 +0300
From:   Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To:     linux-pci@...r.kernel.org, Bjorn Helgaas <helgaas@...nel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Lukas Wunner <lukas@...ner.de>,
        Alexandru Gagniuc <mr.nuke.me@...il.com>,
        Krishna chaitanya chundru <quic_krichai@...cinc.com>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        "Rafael J . Wysocki" <rafael@...nel.org>, linux-pm@...r.kernel.org
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Alex Deucher <alexdeucher@...il.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Amit Kucheria <amitk@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Subject: [PATCH v2 00/10] Add PCIe Bandwidth Controller

Hi all,

This series adds PCIe bandwidth controller (bwctrl) and associated PCIe
cooling driver to the thermal core side for limiting PCIe Link Speed
due to thermal reasons. PCIe bandwidth controller is a PCI express bus
port service driver. A cooling device is created for each port the
service driver finds if they support changing speeds.

This series only adds support for controlling PCIe Link Speed.
Controlling PCIe Link Width might also be useful but AFAIK, there is no
mechanism for that until PCIe 6.0 (L0p). Based on feedback for v1, the
thermal/cooling device side prefers Link Speed and Link Width to be
separate cooling devices [1] which is taken into account in naming the
cooling device for Link Speed but the Link Width one is not added yet
as it would not be able to control anything at the moment.

bwctrl is built on top of BW notifications revert. I'm just not sure
what is the best practice when re-adding some old functionality in a
modified form so please let me know if I need to somehow alter that
patch.

[1] https://lore.kernel.org/linux-pci/f35db90cd67adf4b0f48cd6f2a6ad8fbd0c1a679.camel@linux.intel.com/

v2:
- Adds LNKCTL2 to RMW safe list in Documentation/PCI/pciebus-howto.rst
- Renamed cooling devices from PCIe_Port_* to PCIe_Port_Link_Speed_* in
  order to plan for possibility of adding Link Width cooling devices
  later on
- Moved struct thermal_cooling_device declaration to the correct patch
- Small tweaks to Kconfig texts
- Series rebased to resolve conflict (in the selftest list)

Ilpo Järvinen (10):
  PCI: Protect Link Control 2 Register with RMW locking
  drm/radeon: Use RMW accessors for changing LNKCTL2
  drm/amdgpu: Use RMW accessors for changing LNKCTL2
  drm/IB/hfi1: Use RMW accessors for changing LNKCTL2
  PCI: Store all PCIe Supported Link Speeds
  PCI: Cache PCIe device's Supported Speed Vector
  PCI/LINK: Re-add BW notification portdrv as PCIe BW controller
  PCI/bwctrl: Add "controller" part into PCIe bwctrl
  thermal: Add PCIe cooling driver
  selftests/pcie_bwctrl: Create selftests

 Documentation/PCI/pciebus-howto.rst           |   8 +-
 MAINTAINERS                                   |   8 +
 drivers/gpu/drm/amd/amdgpu/cik.c              |  41 +--
 drivers/gpu/drm/amd/amdgpu/si.c               |  41 +--
 drivers/gpu/drm/radeon/cik.c                  |  40 +--
 drivers/gpu/drm/radeon/si.c                   |  40 +--
 drivers/infiniband/hw/hfi1/pcie.c             |  30 +-
 drivers/pci/pcie/Kconfig                      |   9 +
 drivers/pci/pcie/Makefile                     |   1 +
 drivers/pci/pcie/bwctrl.c                     | 309 ++++++++++++++++++
 drivers/pci/pcie/portdrv.c                    |   9 +-
 drivers/pci/pcie/portdrv.h                    |  10 +-
 drivers/pci/probe.c                           |  38 ++-
 drivers/pci/remove.c                          |   2 +
 drivers/thermal/Kconfig                       |  10 +
 drivers/thermal/Makefile                      |   2 +
 drivers/thermal/pcie_cooling.c                | 107 ++++++
 include/linux/pci-bwctrl.h                    |  33 ++
 include/linux/pci.h                           |   3 +
 include/uapi/linux/pci_regs.h                 |   1 +
 tools/testing/selftests/Makefile              |   1 +
 tools/testing/selftests/pcie_bwctrl/Makefile  |   2 +
 .../pcie_bwctrl/set_pcie_cooling_state.sh     | 122 +++++++
 .../selftests/pcie_bwctrl/set_pcie_speed.sh   |  67 ++++
 24 files changed, 799 insertions(+), 135 deletions(-)
 create mode 100644 drivers/pci/pcie/bwctrl.c
 create mode 100644 drivers/thermal/pcie_cooling.c
 create mode 100644 include/linux/pci-bwctrl.h
 create mode 100644 tools/testing/selftests/pcie_bwctrl/Makefile
 create mode 100755 tools/testing/selftests/pcie_bwctrl/set_pcie_cooling_state.sh
 create mode 100755 tools/testing/selftests/pcie_bwctrl/set_pcie_speed.sh

-- 
2.30.2