[v2,00/11] PCI: qcom: add support for PCIe on SM8450 platform

Message

Dmitry Baryshkov Feb. 4, 2022, 2:46 p.m. UTC

There are two different PCIe controllers and PHYs on SM8450, one having
one lane and another with two lanes. Add support for both PCIe
controllers.

After comparing upstream and downstream Qualcomm PCIe drivers, change
the way the driver works with the pipe_clk_src multiplexing.

The clock should be switched to using ref_clk (TCXO) as a parent before
turning the PCIE_x_GDSC power domain off and can be switched to using
PHY's pipe_clk after this power domain is turned on.

Downstream driver uses regulators for the GDSC, so current approach also
(incorrectly) ties pipe_clk multiplexing to regulator
enablement/disablement. However upstream driver uses power-domain and
so GDSC is maintained using pm_runtime_foo() calls. Previous iteration
of this patchset changed the order of operations to call
pm_runtime_foo(). This iteration changes apprach and moves pipe clock
source handling to the GDSC instead. This way the drivers are sure that
the clock is fed from the correct source.

Changes since v1:
 - Merge two patchsets
 - Move pipe_clk_src handling into the GDSC driver
 - Drop interconnect patch (subject for futher research)
 - Remove "pipe" clock from qcom,pcie bindings as it's removed from the
   source code.

Dmitry Baryshkov (11):
  dt-bindings: pci: qcom,pcie: drop unused "pipe" clocks
  dt-bindings: pci: qcom: Document PCIe bindings for SM8450
  clk: qcom: gdsc: add support for clocks tied to the GDSC
  clk: qcom: gcc-sc7280: switch PCIe GDSCs to pipe_clk_gdsc
  clk: qcom: gcc-sm8450: switch PCIe GDSCs to pipe_clk_gdsc
  PCI: qcom: Balance pm_runtime_foo() calls
  PCI: qcom: Remove unnecessary pipe_clk handling
  PCI: qcom: Remove pipe_clk_src reparenting
  PCI: qcom: Remove redundancy between qcom_pcie and qcom_pcie_cfg
  PCI: qcom: Add ddrss_sf_tbu flag
  PCI: qcom: Add SM8450 PCIe support

 .../devicetree/bindings/pci/qcom,pcie.txt     |  20 +-
 drivers/clk/qcom/gcc-sc7280.c                 | 114 ++++-------
 drivers/clk/qcom/gcc-sm8450.c                 | 104 ++++------
 drivers/clk/qcom/gdsc.c                       |  41 ++++
 drivers/clk/qcom/gdsc.h                       |  14 ++
 drivers/pci/controller/dwc/pcie-qcom.c        | 188 ++++++------------
 6 files changed, 219 insertions(+), 262 deletions(-)