[PATCH 0/4] PCI: dwc: Add PTM sysfs support

[Manivannan Sadhasivam via B4 Relay <devnull+manivannan.sadhasivam.linaro.org@kernel.org>]

Hi,

This series adds sysfs support for PCIe PTM in Synopsys Designware IPs.

First patch moves the common DWC struct definitions (dwc_pcie_vsec_id) to
include/pci/pcie-dwc.h from dwc-pcie-pmu driver. This allows reusing the same
definitions in pcie-designware-sysfs driver introduced in this series and also
in the debugfs series by Shradha [1].

Second patch adds support for searching the Vendor Specific Extended Capability
(VSEC) in the pcie-designware driver. This patch was originally based on
Shradha's patch [2], but modified to accept 'struct dwc_pcie_vsec_id' to avoid
iterating through the vsec_ids in the driver.

Third patch adds the actual sysfs support for PTM in a new file
pcie-designware-sysfs.c built along with pcie-designware.c.

Finally, fourth patch masks the PTM_UPDATING interrupt in the pcie-qcom-ep
driver to avoid processing the interrupt for each PTM context update.

Testing
=======

This series is tested on Qcom SA8775p Ride Mx platform where one SA8775p acts as
RC and another as EP with following instructions:

RC
--

$ echo 1 > /sys/devices/platform/1c10000.pcie/dwc/ptm/ptm_context_valid

EP
--

$ echo auto > /sys/devices/platform/1c10000.pcie-ep/dwc/ptm/ptm_context_update

$ cat /sys/devices/platform/1c10000.pcie-ep/dwc/ptm/ptm_local_clock
159612570424

$ cat /sys/devices/platform/1c10000.pcie-ep/dwc/ptm/ptm_master_clock
159609466232

$ cat /sys/devices/platform/1c10000.pcie-ep/dwc/ptm/ptm_t1
159609466112

$ cat /sys/devices/platform/1c10000.pcie-ep/dwc/ptm/ptm_t4
159609466518

NOTE: To make use of the PTM feature, the host PCIe client driver has to call
'pci_enable_ptm()' API during probe. This series was tested with enabling PTM in
the MHI host driver with a local change (which will be upstreamed later).
Technically, PTM could also be enabled in the pci_endpoint_test driver, but I
didn't add the change as I'm not sure we'd want to add random PCIe features in
the test driver without corresponding code in pci-epf-test driver.

Merging Strategy
================

I'd like to have an ACK from the perf maintainers to take the whole series
through PCI tree.

[1] https://lore.kernel.org/linux-pci/20250214105007.97582-1-shradha.t@samsung.com
[2] https://lore.kernel.org/linux-pci/20250214105007.97582-2-shradha.t@samsung.com

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
Manivannan Sadhasivam (4):
      perf/dwc_pcie: Move common DWC struct definitions to 'pcie-dwc.h'
      PCI: dwc: Add helper to find the Vendor Specific Extended Capability (VSEC)
      PCI: dwc: Add sysfs support for PTM
      PCI: qcom-ep: Mask PTM_UPDATING interrupt

 Documentation/ABI/testing/sysfs-platform-dwc-pcie  |  70 ++++++
 MAINTAINERS                                        |   2 +
 drivers/pci/controller/dwc/Makefile                |   2 +-
 drivers/pci/controller/dwc/pcie-designware-ep.c    |   3 +
 drivers/pci/controller/dwc/pcie-designware-host.c  |   4 +
 drivers/pci/controller/dwc/pcie-designware-sysfs.c | 278 +++++++++++++++++++++
 drivers/pci/controller/dwc/pcie-designware.c       |  46 ++++
 drivers/pci/controller/dwc/pcie-designware.h       |  22 ++
 drivers/pci/controller/dwc/pcie-qcom-ep.c          |   8 +
 drivers/perf/dwc_pcie_pmu.c                        |  23 +-
 include/linux/pcie-dwc.h                           |  42 ++++
 11 files changed, 478 insertions(+), 22 deletions(-)
---
base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b
change-id: 20250218-pcie-qcom-ptm-bf6952f5c4e5

Best regards,
-- 
Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>