[PATCH v3 00/10] Add PCIe Bandwidth Controller

Ilpo Järvinen
2023-09-29T11:57:44Z

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/

v3:
- Correct hfi1 shortlog prefix
- Improve error prints in hfi1
- Add L: linux-pci to the MAINTAINERS entry

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
RDMA/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 | 9 +
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, 800 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

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2.30.2