Re: [PATCH v6 0/5] PCI: qcom: Add system suspend & resume support

[Krishna Chaitanya Chundru]

On 9/12/2022 11:07 PM, Manivannan Sadhasivam wrote:
> On Fri, Sep 09, 2022 at 02:14:39PM +0530, Krishna chaitanya chundru wrote:
> > Add suspend and resume syscore ops.
> >
> > When system suspends, and if the link is in L1ss, disable the clocks
> > and power down the phy so that system enters into low power state by
> > parking link in L1ss to save the maximum power. And when the system
> > resumes, enable the clocks back and power on phy if they are disabled
> > in the suspend path.
> You need to mention that you are only turning off the PCIe controller
> clocks and PHY is still powered by a separate domain (MX) so the link
> statys intact.
sure I will update the commit in next series.
> > we are doing this only when link is in l1ss but not in L2/L3 as
> > nowhere we are forcing link to L2/L3 by sending PME turn off.
> >
> > is_suspended flag indicates if the clocks are disabled in the suspend
> > path or not.
> >
> > There is access to Ep PCIe space to mask MSI/MSIX after pm suspend ops
> > (getting hit by affinity changes while making CPUs offline during suspend,
> > this will happen after devices are suspended (all phases of suspend ops)).
> > When registered with pm ops there is a crash due to un-clocked access,
> > as in the pm suspend op clocks are disabled. So, registering with syscore
> > ops which will called after making CPUs offline.
> >
> > Make GDSC always on to ensure controller and its dependent clocks
> > won't go down during system suspend.
> Where is the changelog? You seem to have added PHY and CLK patches to
> this series. You need to comment on that.
>
> Thanks,
> Mani
I will update that in next patch.
> > Krishna chaitanya chundru (5):
> >    PCI: qcom: Add system suspend and resume support
> >    PCI: qcom: Add retry logic for link to be stable in L1ss
> >    phy: core: Add support for phy power down & power up
> >    phy: qcom: Add power down/up callbacks to pcie phy
> >    clk: qcom: Alwaya on pcie gdsc
> >
> >   drivers/clk/qcom/gcc-sc7280.c            |   2 +-
> >   drivers/pci/controller/dwc/pcie-qcom.c   | 156 ++++++++++++++++++++++++++++++-
> >   drivers/phy/phy-core.c                   |  30 ++++++
> >   drivers/phy/qualcomm/phy-qcom-qmp-pcie.c |  50 ++++++++++
> >   include/linux/phy/phy.h                  |  20 ++++
> >   5 files changed, 256 insertions(+), 2 deletions(-)
> >
> > --
> > 2.7.4