[PATCH v7 0/4] PCI: qcom: Add 16.0 GT/s equalization and margining settings

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

Hi,

This series adds 16.0 GT/s specific equalization and RX lane margining settings
to the Qcom RC and EP drivers. This series is mandatory for the stable operation
of the PCIe link at 16.0 GT/s on the Qcom platforms.

NOTE:
=====

I've taken over the series from Shashank based on the discussion [1]. In order
to apply the equalization/margining settings properly in the Qcom driver, I
added the first 2 patches to the series which inevitably touches other vendor
drivers also.

- Mani

Changes in v7:
- Fixed the build issue reported by Kbuild bot in patch 1/4
- Changed the logic to check invalid max_link_speed in patch 2/4
- Cleanups to patches 3/4 and 4/4 as suggested by Johan
- Added include header guard to pci-qcom-common.h
- Link to v6: https://lore.kernel.org/r/20240904-pci-qcom-gen4-stability-v6-0-ec39f7ae3f62@linaro.org

Changes in v6:

- Dropped the code refactoring patch as suggested by Johan
- Added 2 patches to fix the caching of maximum supported link speed value that
  is needed to apply the equalization/margining settings
- Updated the commit message of patch 3 as per Bjorn's suggestion

For previous changelogs, please refer [2]

[1] https://lore.kernel.org/linux-pci/af65b744-7538-4929-9ab4-8ee42e17b8d1@quicinc.com/
[2] https://lore.kernel.org/linux-pci/20240821170917.21018-1-quic_schintav@quicinc.com/

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
Manivannan Sadhasivam (2):
      PCI: dwc: Rename 'dw_pcie::link_gen' to 'dw_pcie::max_link_speed'
      PCI: dwc: Always cache the maximum link speed value in dw_pcie::max_link_speed

Shashank Babu Chinta Venkata (2):
      PCI: qcom: Add equalization settings for 16.0 GT/s
      PCI: qcom: Add RX lane margining settings for 16.0 GT/s

 MAINTAINERS                                   |  4 +-
 drivers/pci/controller/dwc/Kconfig            |  5 ++
 drivers/pci/controller/dwc/Makefile           |  1 +
 drivers/pci/controller/dwc/pci-imx6.c         |  8 +--
 drivers/pci/controller/dwc/pcie-designware.c  | 22 +++++---
 drivers/pci/controller/dwc/pcie-designware.h  | 33 +++++++++++-
 drivers/pci/controller/dwc/pcie-intel-gw.c    |  4 +-
 drivers/pci/controller/dwc/pcie-qcom-common.c | 78 +++++++++++++++++++++++++++
 drivers/pci/controller/dwc/pcie-qcom-common.h | 14 +++++
 drivers/pci/controller/dwc/pcie-qcom-ep.c     |  6 +++
 drivers/pci/controller/dwc/pcie-qcom.c        |  6 +++
 drivers/pci/controller/dwc/pcie-rcar-gen4.c   |  6 +--
 drivers/pci/controller/dwc/pcie-spear13xx.c   |  2 +-
 drivers/pci/controller/dwc/pcie-tegra194.c    | 19 +++----
 14 files changed, 178 insertions(+), 30 deletions(-)
---
base-commit: 47ac09b91befbb6a235ab620c32af719f8208399
change-id: 20240904-pci-qcom-gen4-stability-02ec65a7e6e4

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