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[v5,0/3] PCI: Restrict pci transactions after pci suspend

Message ID 1659526134-22978-1-git-send-email-quic_krichai@quicinc.com
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Series PCI: Restrict pci transactions after pci suspend | expand

Message

Krishna chaitanya chundru Aug. 3, 2022, 11:28 a.m. UTC 
If the endpoint device state is D0 and irq's are not freed, then
kernel try to mask interrupts in system suspend path by writing in to
the vector table (for MSIX interrupts) and config space (for MSI's).

These transactions are initiated in the pm suspend after pcie clocks got
disabled as part of platform driver pm  suspend call. Due to it, these
transactions are resulting in un-clocked access and eventually to crashes.

So added a logic in qcom driver to restrict these unclocked access.
And updated the logic to check the link state before masking
or unmasking the interrupts.

And some devices are taking time to settle the link in L1ss, so added a
retry logic in the suspend ops.

Krishna chaitanya chundru (3):
  PCI: qcom: Add system PM support
  PCI: qcom: Restrict pci transactions after pci suspend
  PCI: qcom: Add retry logic for link to be stable in L1ss

 drivers/pci/controller/dwc/pcie-designware-host.c |  14 ++-
 drivers/pci/controller/dwc/pcie-qcom.c            | 117 +++++++++++++++++++++-
 2 files changed, 127 insertions(+), 4 deletions(-)

Comments

Bjorn Helgaas Aug. 24, 2022, 8:29 p.m. UTC | #1 
On Wed, Aug 03, 2022 at 04:58:51PM +0530, Krishna chaitanya chundru wrote:
> If the endpoint device state is D0 and irq's are not freed, then
> kernel try to mask interrupts in system suspend path by writing in to
> the vector table (for MSIX interrupts) and config space (for MSI's).

If clocks are being turned off while the PCI core is still accessing
the device, I think that means qcom suspend is not implemented
correctly.

> These transactions are initiated in the pm suspend after pcie clocks got
> disabled as part of platform driver pm  suspend call. Due to it, these
> transactions are resulting in un-clocked access and eventually to crashes.
> 
> So added a logic in qcom driver to restrict these unclocked access.
> And updated the logic to check the link state before masking
> or unmasking the interrupts.
> 
> And some devices are taking time to settle the link in L1ss, so added a
> retry logic in the suspend ops.
> 
> Krishna chaitanya chundru (3):
>   PCI: qcom: Add system PM support
>   PCI: qcom: Restrict pci transactions after pci suspend
>   PCI: qcom: Add retry logic for link to be stable in L1ss
> 
>  drivers/pci/controller/dwc/pcie-designware-host.c |  14 ++-
>  drivers/pci/controller/dwc/pcie-qcom.c            | 117 +++++++++++++++++++++-
>  2 files changed, 127 insertions(+), 4 deletions(-)
> 
> -- 
> 2.7.4
>