- Use uniform language in Kconfig menu entries (Bjorn Helgaas)

- Sort controller Kconfig entries by vendor (Bjorn Helgaas)

* pci/controller/kconfig:
  PCI: xilinx: Drop obsolete dependency on COMPILE_TEST
  PCI: mobiveil: Sort Kconfig entries by vendor
  PCI: dwc: Sort Kconfig entries by vendor
  PCI: Sort controller Kconfig entries by vendor
  PCI: Use consistent controller Kconfig menu entry language
  PCI: xilinx-nwl: Add 'Xilinx' to Kconfig prompt
  PCI: hv: Add 'Microsoft' to Kconfig prompt
  PCI: meson: Add 'Amlogic' to Kconfig prompt
  PCI: Use of_property_present() for testing DT property presence
  PCI/PM: Extend D3hot delay for NVIDIA HDA controllers
  dt-bindings: PCI: qcom: Document msi-map and msi-map-mask properties
  PCI: qcom: Add SM8550 PCIe support
  dt-bindings: PCI: qcom: Add SM8550 compatible
  PCI: qcom: Add support for SDX55 SoC
  dt-bindings: PCI: qcom-ep: Fix the unit address used in example
  dt-bindings: PCI: qcom: Add SDX55 SoC
  dt-bindings: PCI: qcom: Update maintainers entry
  PCI: qcom: Enable async probe by default
  PCI: qcom: Add support for system suspend and resume
  PCI/PM: Drop pci_bridge_wait_for_secondary_bus() timeout parameter
  PCI/PM: Increase wait time after resume
  PCI: pciehp: Fix AB-BA deadlock between reset_lock and device_lock
  PCI: Fix up L1SS capability for Intel Apollo Lake Root Port
  PCI: qcom: Expose link transition counts via debugfs
  dt-bindings: PCI: qcom: Add "mhi" register region to supported SoCs
  PCI: qcom: Rename qcom_pcie_config_sid_sm8250() to reflect IP version
  PCI: qcom: Use macros for defining total no. of clocks & supplies
  PCI: qcom: Use bulk reset APIs for handling resets for IP rev 2.4.0
  PCI: qcom: Use bulk reset APIs for handling resets for IP rev 2.3.3
  PCI: qcom: Use bulk clock APIs for handling clocks for IP rev 2.3.3
  PCI: qcom: Use bulk clock APIs for handling clocks for IP rev 2.3.2
  PCI: qcom: Use bulk clock APIs for handling clocks for IP rev 1.0.0
  PCI: qcom: Use bulk reset APIs for handling resets for IP rev 2.1.0
  PCI: qcom: Use lower case for hex
  PCI: qcom: Add missing macros for register fields
  PCI: qcom: Use bitfield definitions for register fields
  PCI: qcom: Sort and group registers and bitfield definitions
  PCI: qcom: Remove PCIE20_ prefix from register definitions
  PCI: qcom: Fix the incorrect register usage in v2.7.0 config
  PCI/EDR: Add edr_handle_event() comments
  PCI/EDR: Clear Device Status after EDR error recovery
  efi/cper: Remove unnecessary aer.h include
  dt-bindings: imx6q-pcie: Restruct i.MX PCIe schema
  PCI/P2PDMA: Fix pci_p2pmem_find_many() kernel-doc
  EISA: Drop unused pci_bus_for_each_resource() index argument
  PCI: Make pci_bus_for_each_resource() index optional
  PCI: Document pci_bus_for_each_resource()
  PCI: Introduce pci_dev_for_each_resource()
  PCI: Introduce pci_resource_n()
  PCI: ixp4xx: Use PCI_CONF1_ADDRESS() macro
  PCI: mt7621: Use dev_info() to log PCIe card detection
  PCI: imx6: Install the fault handler only on compatible match
  PCI: layerscape: Add EP mode support for ls1028a
  PCI: rcar: Avoid defines prefixed with CONFIG
  dt-bindings: PCI: convert amlogic,meson-pcie.txt to dt-schema
  PCI: kirin: Select REGMAP_MMIO

Since commit 0166dc11 ("of: make CONFIG_OF user selectable"), it is
possible to test-build any driver which depends on OF on any architecture
by explicitly selecting OF. Therefore depending on COMPILE_TEST as an
alternative is no longer needed.

Link: https://lore.kernel.org/r/20230407190843.529caf19@endymion.delvareSigned-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: "Krzysztof Wilczyński" <kw@linux.com>

Sort Kconfig entries by vendor so they appear in alphabetical order in
menuconfig.

Link: https://lore.kernel.org/r/20230418174336.145585-8-helgaas@kernel.orgSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>

Sort Kconfig entries by vendor so they appear in alphabetical order in
menuconfig.

Link: https://lore.kernel.org/r/20230418174336.145585-7-helgaas@kernel.orgSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>

Sort Kconfig entries by vendor so they appear in alphabetical order in
menuconfig.

Link: https://lore.kernel.org/r/20230418174336.145585-6-helgaas@kernel.orgSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>

Use "PCIe controller" consistently instead of "host bridge", "bus driver",
etc.  Annotate with "(host mode)" or "(endpoint mode)" as needed.

Link: https://lore.kernel.org/r/20230418174336.145585-5-helgaas@kernel.orgSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>

Add the "Xilinx" vendor name to the CONFIG_PCIE_XILINX_NWL Kconfig prompt
so it matches other drivers.  Rename from "PCIe Core" to "PCIe controller".

Link: https://lore.kernel.org/r/20230418174336.145585-4-helgaas@kernel.orgSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Michal Simek <michal.simek@amd.com>

Add the "Microsoft" vendor name to the CONFIG_PCI_HYPERV_INTERFACE Kconfig
prompt so it matches other PCIe drivers and other Hyper-V prompts.

Link: https://lore.kernel.org/r/20230418174336.145585-3-helgaas@kernel.orgSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>

Add the "Amlogic" vendor name to the CONFIG_PCI_MESON Kconfig prompt to
match other PCIe drivers.  Capitalize "Meson" to match other Meson Kconfig
prompts.

Link: https://lore.kernel.org/r/20230418174336.145585-2-helgaas@kernel.orgSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Yue Wang <yue.wang@Amlogic.com>

- Rename internal #defines without "CONFIG_" prefix to avoid confusion
  (Lukas Bulwahn)

* pci/controller/rcar:
  PCI: rcar: Avoid defines prefixed with CONFIG

- Use correct PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT_V2 register for v2.7.0
  (Manivannan Sadhasivam)

- Remove "PCIE20_" prefix from register definitions (Manivannan Sadhasivam)

- Sort registers and bitfield declarations (Manivannan Sadhasivam)

- Convert to GENMASK and FIELD_PREP (Manivannan Sadhasivam)

- Use bulk APIs for clocks of IP 1.0.0, 2.3.2, 2.3.3 (Manivannan
  Sadhasivam)

- Use bulk APIs for reset of IP 2.1.0, 2.3.3, 2.4.0 (Manivannan Sadhasivam)

- Rename qcom_pcie_config_sid_sm8250() to be non SM8250-specific
  (Manivannan Sadhasivam)

- Add DT "mhi" register region for supported SoCs (Manivannan Sadhasivam)

- Expose link transition counts via debugfs to help debug low power issues
  (Manivannan Sadhasivam)

- Support system suspend and resume; reduce interconnect bandwidth and turn
  off clock and PHY if there are no active devices (Manivannan Sadhasivam)

- Enable async probe by default to reduce boot time (Manivannan Sadhasivam)

- Add Manivannan Sadhasivam as qcom DT binding maintainer, replacing
  Stanimir Varbanov (Manivannan Sadhasivam)

- Add DT binding and driver support for Qcom SDX55 SoC (Manivannan
  Sadhasivam)

- Add DT binding and driver support for SM8550 SoC (Abel Vesa)

- Document msi-map and msi-map-mask DT properties (Manivannan Sadhasivam)

* pci/controller/qcom:
  dt-bindings: PCI: qcom: Document msi-map and msi-map-mask properties
  PCI: qcom: Add SM8550 PCIe support
  dt-bindings: PCI: qcom: Add SM8550 compatible
  PCI: qcom: Add support for SDX55 SoC
  dt-bindings: PCI: qcom-ep: Fix the unit address used in example
  dt-bindings: PCI: qcom: Add SDX55 SoC
  dt-bindings: PCI: qcom: Update maintainers entry
  PCI: qcom: Enable async probe by default
  PCI: qcom: Add support for system suspend and resume
  PCI: qcom: Expose link transition counts via debugfs
  dt-bindings: PCI: qcom: Add "mhi" register region to supported SoCs
  PCI: qcom: Rename qcom_pcie_config_sid_sm8250() to reflect IP version
  PCI: qcom: Use macros for defining total no. of clocks & supplies
  PCI: qcom: Use bulk reset APIs for handling resets for IP rev 2.4.0
  PCI: qcom: Use bulk reset APIs for handling resets for IP rev 2.3.3
  PCI: qcom: Use bulk clock APIs for handling clocks for IP rev 2.3.3
  PCI: qcom: Use bulk clock APIs for handling clocks for IP rev 2.3.2
  PCI: qcom: Use bulk clock APIs for handling clocks for IP rev 1.0.0
  PCI: qcom: Use bulk reset APIs for handling resets for IP rev 2.1.0
  PCI: qcom: Use lower case for hex
  PCI: qcom: Add missing macros for register fields
  PCI: qcom: Use bitfield definitions for register fields
  PCI: qcom: Sort and group registers and bitfield definitions
  PCI: qcom: Remove PCIE20_ prefix from register definitions
  PCI: qcom: Fix the incorrect register usage in v2.7.0 config

- Log empty slots with dev_info(), not dev_err() (Sergio Paracuellos)

* pci/controller/mt7621:
  PCI: mt7621: Use dev_info() to log PCIe card detection

- Add ls1028a endpoint mode support (Xiaowei Bao)

* pci/controller/layerscape:
  PCI: layerscape: Add EP mode support for ls1028a

- Select CONFIG_REGMAP_MMIO so kirin driver links correctly (Josh Triplett)

* pci/controller/kirin:
  PCI: kirin: Select REGMAP_MMIO

- Use the PCI_CONF1_ADDRESS() macro to simplify config space address
  computation (Pali Rohár)

* pci/controller/ixp4xx:
  PCI: ixp4xx: Use PCI_CONF1_ADDRESS() macro

- Install i.MX6 PCI abort handler only when DT contains a PCI controller
  claimed by the imx6 driver (H. Nikolaus Schaller)

* pci/controller/dwc:
  PCI: imx6: Install the fault handler only on compatible match

- Convert Amlogic Meson AXG DWC PCIe SoC controller bindings to dt-schema
  (Neil Armstrong)

- Restructure i.MX schema to extract common properties to be shared by Root
  Complex and Endpoint schema (Richard Zhu)

* pci/controller/dt:
  dt-bindings: imx6q-pcie: Restruct i.MX PCIe schema
  dt-bindings: PCI: convert amlogic,meson-pcie.txt to dt-schema

- Add pci_dev_for_each_resource() and pci_bus_for_each_resource() iterators
  to simplify loops (Andy Shevchenko)

* pci/resource:
  EISA: Drop unused pci_bus_for_each_resource() index argument
  PCI: Make pci_bus_for_each_resource() index optional
  PCI: Document pci_bus_for_each_resource()
  PCI: Introduce pci_dev_for_each_resource()
  PCI: Introduce pci_resource_n()

- Wait longer for devices to become ready after resume (as we do for reset)
  to accommodate Intel Titan Ridge xHCI devices (Mika Westerberg)

- Drop pci_bridge_wait_for_secondary_bus() timeout parameter since all
  callers pass the same value (Mika Westerberg)

- Extend D3hot delay for NVIDIA HDA controllers to avoid unrecoverable
  devices after a bus reset (Alex Williamson)

* pci/reset:
  PCI/PM: Extend D3hot delay for NVIDIA HDA controllers
  PCI/PM: Drop pci_bridge_wait_for_secondary_bus() timeout parameter
  PCI/PM: Increase wait time after resume

- Fix pci_p2pmem_find_many() kernel-doc (Cai Huoqing)

* pci/p2pdma:
  PCI/P2PDMA: Fix pci_p2pmem_find_many() kernel-doc

- Fix pciehp AB-BA deadlock between reset_lock and device_lock (Lukas
  Wunner)

* pci/hotplug:
  PCI: pciehp: Fix AB-BA deadlock between reset_lock and device_lock

- Use of_property_present(), instead of lower-level functions like
  of_get_property(), for testing DT property presence (Rob Herring)

* pci/enumeration:
  PCI: Use of_property_present() for testing DT property presence

- Work around Chromebook firmware issue that corrupts Extended Capability
  list (including L1 PM Substates capability) on D3cold -> D0 transitions
  (Ron Lee)

* pci/aspm:
  PCI: Fix up L1SS capability for Intel Apollo Lake Root Port

- Remove unnecessary <linux/aer.h> includes (Bjorn Helgaas)

- Clear Device Status after EDR error recovery.  Firmware collects EDR
  error information, but the OS is responsible for clearing it (Kuppuswamy
  Sathyanarayanan)

* pci/aer:
  PCI/EDR: Add edr_handle_event() comments
  PCI/EDR: Clear Device Status after EDR error recovery
  efi/cper: Remove unnecessary aer.h include

It is preferred to use typed property access functions (i.e.
of_property_read_<type> functions) rather than low-level
of_get_property()/of_find_property() functions for reading properties. As
part of this, convert of_get_property()/of_find_property() calls to the
recently added of_property_present() helper when we just want to test for
presence of a property and nothing more.

Link: https://lore.kernel.org/r/20230310144719.1544443-1-robh@kernel.orgSigned-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>  # pcie-mediatek

Assignment of NVIDIA Ampere-based GPUs have seen a regression since the
below referenced commit, where the reduced D3hot transition delay appears
to introduce a small window where a D3hot->D0 transition followed by a bus
reset can wedge the device.  The entire device is subsequently unavailable,
returning -1 on config space read and is unrecoverable without a host
reset.

This has been observed with RTX A2000 and A5000 GPU and audio functions
assigned to a Windows VM, where shutdown of the VM places the devices in
D3hot prior to vfio-pci performing a bus reset when userspace releases the
devices.  The issue has roughly a 2-3% chance of occurring per shutdown.

Restoring the HDA controller d3hot_delay to the effective value before the
below commit has been shown to resolve the issue.  NVIDIA confirms this
change should be safe for all of their HDA controllers.

Fixes: 3e347969 ("PCI/PM: Reduce D3hot delay with usleep_range()")
Link: https://lore.kernel.org/r/20230413194042.605768-1-alex.williamson@redhat.comReported-by: Zhiyi Guo <zhguo@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Tarun Gupta <targupta@nvidia.com>
Cc: Abhishek Sahu <abhsahu@nvidia.com>
Cc: Tarun Gupta <targupta@nvidia.com>

The Qcom PCIe controller is capable of using either internal MSI controller
or the external GIC-ITS for signaling MSIs sent by endpoint devices.
Currently, the binding only documents the internal MSI implementation.

Let's document the GIC-ITS imeplementation by making use of msi-map and
msi-map-mask properties. Only one of the implementation should be used
at a time and the drivers can choose the preferred one.

Link: https://lore.kernel.org/r/20230411121442.22227-1-manivannan.sadhasivam@linaro.orgSigned-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>

SM8550 requires two additional clocks for proper working.

Add these two clocks as optional clocks (as only required by this
platform) and compatible for this platform.

While at it, let's also rename the reset variable to "rst" from
"pci_reset" to match the existing naming preference.

Link: https://lore.kernel.org/r/20230320144658.1794991-2-abel.vesa@linaro.orgSigned-off-by: Abel Vesa <abel.vesa@linaro.org>
[lpieralisi@kernel.org: commit log rewording]
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>

Add the SM8550 platform to the binding.

Link: https://lore.kernel.org/r/20230320144658.1794991-1-abel.vesa@linaro.orgSigned-off-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>

Add support for SDX55 SoC reusing the 1.9.0 config. The PCIe controller is
of version 1.10.0 but it is compatible with the 1.9.0 config. This SoC also
requires "sleep" clock which is added as an optional clock in the driver,
since it is not required on other SoCs.

Link: https://lore.kernel.org/r/20230308082424.140224-14-manivannan.sadhasivam@linaro.orgSigned-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>

Unit address of PCIe EP node should be 0x1c00000 as it has to match the
first address specified in the reg property.

Link: https://lore.kernel.org/r/20230308082424.140224-5-manivannan.sadhasivam@linaro.org
Fixes: 31c9ef00 ("dt-bindings: PCI: Add Qualcomm PCIe Endpoint controller")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Add support for the PCIe controller on the Qcom SDX55 SoC to the binding.

Link: https://lore.kernel.org/r/20230308082424.140224-4-manivannan.sadhasivam@linaro.orgSigned-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Stan is no longer working with MMSOL and expressed his interest to not
continue maintaining Qcom PCIe driver. Since I took over the driver
maintainership, I'm stepping in to maintain the binding also.

Link: https://lore.kernel.org/r/20230308082424.140224-2-manivannan.sadhasivam@linaro.orgSigned-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Qcom PCIe RC driver waits for the PHY link to be up during the probe;
this consumes several milliseconds during boot.

Enable async probe by default so that other drivers can load in parallel
while this driver waits for the link to be up.
Suggested-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230320064644.5217-1-manivannan.sadhasivam@linaro.orgTested-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>

During the system suspend, vote for minimal interconnect bandwidth (1KiB)
to keep the interconnect path active for config access and also turn OFF
the resources like clock and PHY if there are no active devices connected
to the controller. For the controllers with active devices, the resources
are kept ON as removing the resources will trigger access violation during
the late end of suspend cycle as kernel tries to access the config space of
PCIe devices to mask the MSIs.

Also, it is not desirable to put the link into L2/L3 state as that
implies VDD supply will be removed and the devices may go into powerdown
state. This will affect the lifetime of storage devices like NVMe.

And finally, during resume, turn ON the resources if the controller was
truly suspended (resources OFF) and update the interconnect bandwidth
based on PCIe Gen speed.
Suggested-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
Link: https://lore.kernel.org/r/20230403154922.20704-2-manivannan.sadhasivam@linaro.orgTested-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Acked-by: Dhruva Gole <d-gole@ti.com>

All callers of pci_bridge_wait_for_secondary_bus() supply a timeout of
PCIE_RESET_READY_POLL_MS, so drop the parameter.  Move the definition of
PCIE_RESET_READY_POLL_MS into pci.c, the only user.

[bhelgaas: extracted from
https://lore.kernel.org/r/20230404052714.51315-3-mika.westerberg@linux.intel.com]
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCIe r6.0 sec 6.6.1 prescribes that a device must be able to respond to
config requests within 1.0 s (PCI_RESET_WAIT) after exiting conventional
reset and this same delay is prescribed when coming out of D3cold (as that
involves reset too).

A device that requires more than 1 second to initialize after reset may
respond to config requests with Request Retry Status completions (sec
2.3.1), and we accommodate that in Linux with a 60 second cap
(PCIE_RESET_READY_POLL_MS).

Previously we waited up to PCIE_RESET_READY_POLL_MS only in the reset code
path, not in the resume path.  However, a device has surfaced, namely Intel
Titan Ridge xHCI, which requires a longer delay also in the resume code
path.

Make the resume code path to use this same extended delay as the reset
path.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216728
Link: https://lore.kernel.org/r/20230404052714.51315-2-mika.westerberg@linux.intel.comReported-by: Chris Chiu <chris.chiu@canonical.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Lukas Wunner <lukas@wunner.de>

In 2013, commits

  2e35afae ("PCI: pciehp: Add reset_slot() method")
  608c3881 ("PCI: Add slot reset option to pci_dev_reset()")

amended PCIe hotplug to mask Presence Detect Changed events during a
Secondary Bus Reset.  The reset thus no longer causes gratuitous slot
bringdown and bringup.

However the commits neglected to serialize reset with code paths reading
slot registers.  For instance, a slot bringup due to an earlier hotplug
event may see the Presence Detect State bit cleared during a concurrent
Secondary Bus Reset.

In 2018, commit

  5b3f7b7d ("PCI: pciehp: Avoid slot access during reset")

retrofitted the missing locking.  It introduced a reset_lock which
serializes a Secondary Bus Reset with other parts of pciehp.

Unfortunately the locking turns out to be overzealous:  reset_lock is
held for the entire enumeration and de-enumeration of hotplugged devices,
including driver binding and unbinding.

Driver binding and unbinding acquires device_lock while the reset_lock
of the ancestral hotplug port is held.  A concurrent Secondary Bus Reset
acquires the ancestral reset_lock while already holding the device_lock.
The asymmetric locking order in the two code paths can lead to AB-BA
deadlocks.

Michael Haeuptle reports such deadlocks on simultaneous hot-removal and
vfio release (the latter implies a Secondary Bus Reset):

  pciehp_ist()                                    # down_read(reset_lock)
    pciehp_handle_presence_or_link_change()
      pciehp_disable_slot()
        __pciehp_disable_slot()
          remove_board()
            pciehp_unconfigure_device()
              pci_stop_and_remove_bus_device()
                pci_stop_bus_device()
                  pci_stop_dev()
                    device_release_driver()
                      device_release_driver_internal()
                        __device_driver_lock()    # device_lock()

  SYS_munmap()
    vfio_device_fops_release()
      vfio_device_group_close()
        vfio_device_close()
          vfio_device_last_close()
            vfio_pci_core_close_device()
              vfio_pci_core_disable()             # device_lock()
                __pci_reset_function_locked()
                  pci_reset_bus_function()
                    pci_dev_reset_slot_function()
                      pci_reset_hotplug_slot()
                        pciehp_reset_slot()       # down_write(reset_lock)

Ian May reports the same deadlock on simultaneous hot-removal and an
AER-induced Secondary Bus Reset:

  aer_recover_work_func()
    pcie_do_recovery()
      aer_root_reset()
        pci_bus_error_reset()
          pci_slot_reset()
            pci_slot_lock()                       # device_lock()
            pci_reset_hotplug_slot()
              pciehp_reset_slot()                 # down_write(reset_lock)

Fix by releasing the reset_lock during driver binding and unbinding,
thereby splitting and shrinking the critical section.

Driver binding and unbinding is protected by the device_lock() and thus
serialized with a Secondary Bus Reset.  There's no need to additionally
protect it with the reset_lock.  However, pciehp does not bind and
unbind devices directly, but rather invokes PCI core functions which
also perform certain enumeration and de-enumeration steps.

The reset_lock's purpose is to protect slot registers, not enumeration
and de-enumeration of hotplugged devices.  That would arguably be the
job of the PCI core, not the PCIe hotplug driver.  After all, an
AER-induced Secondary Bus Reset may as well happen during boot-time
enumeration of the PCI hierarchy and there's no locking to prevent that
either.

Exempting *de-enumeration* from the reset_lock is relatively harmless:
A concurrent Secondary Bus Reset may foil config space accesses such as
PME interrupt disablement.  But if the device is physically gone, those
accesses are pointless anyway.  If the device is physically present and
only logically removed through an Attention Button press or the sysfs
"power" attribute, PME interrupts as well as DMA cannot come through
because pciehp_unconfigure_device() disables INTx and Bus Master bits.
That's still protected by the reset_lock in the present commit.

Exempting *enumeration* from the reset_lock also has limited impact:
The exempted call to pci_bus_add_device() may perform device accesses
through pcibios_bus_add_device() and pci_fixup_device() which are now
no longer protected from a concurrent Secondary Bus Reset.  Otherwise
there should be no impact.

In essence, the present commit seeks to fix the AB-BA deadlocks while
still retaining a best-effort reset protection for enumeration and
de-enumeration of hotplugged devices -- until a general solution is
implemented in the PCI core.

Link: https://lore.kernel.org/linux-pci/CS1PR8401MB0728FC6FDAB8A35C22BD90EC95F10@CS1PR8401MB0728.NAMPRD84.PROD.OUTLOOK.COM
Link: https://lore.kernel.org/linux-pci/20200615143250.438252-1-ian.may@canonical.com
Link: https://lore.kernel.org/linux-pci/ce878dab-c0c4-5bd0-a725-9805a075682d@amd.com
Link: https://lore.kernel.org/linux-pci/ed831249-384a-6d35-0831-70af191e9bce@huawei.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215590
Fixes: 5b3f7b7d ("PCI: pciehp: Avoid slot access during reset")
Link: https://lore.kernel.org/r/fef2b2e9edf245c049a8c5b94743c0f74ff5008a.1681191902.git.lukas@wunner.deReported-by: Michael Haeuptle <michael.haeuptle@hpe.com>
Reported-by: Ian May <ian.may@canonical.com>
Reported-by: Andrey Grodzovsky <andrey2805@gmail.com>
Reported-by: Rahul Kumar <rahul.kumar1@amd.com>
Reported-by: Jialin Zhang <zhangjialin11@huawei.com>
Tested-by: Anatoli Antonovitch <Anatoli.Antonovitch@amd.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v4.19+
Cc: Dan Stein <dstein@hpe.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Alex Michon <amichon@kalrayinc.com>
Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Sathyanarayanan Kuppuswamy <sathyanarayanan.kuppuswamy@linux.intel.com>

On Google Coral and Reef family Chromebooks with Intel Apollo Lake SoC,
firmware clobbers the header of the L1 PM Substates capability and the
previous capability when returning from D3cold to D0.

Save those headers at enumeration-time and restore them at resume.

[bhelgaas: The main benefit is to make the lspci output after resume
correct.  Apparently there's little or no effect on power consumption.]

Link: https://lore.kernel.org/linux-pci/CAFJ_xbq0cxcH-cgpXLU4Mjk30+muWyWm1aUZGK7iG53yaLBaQg@mail.gmail.com/T/#u
Link: https://lore.kernel.org/r/20230411160213.4453-1-ron.lee@intel.comSigned-off-by: Ron Lee <ron.lee@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Qualcomm PCIe controllers have debug registers in the MHI region that
count PCIe link transitions. Expose them over debugfs to userspace to
help debug the low power issues.

Note that even though the registers are prefixed as PARF_, they don't
live under the "parf" register region. The register naming is following
the Qualcomm's internal documentation as like other registers.

While at it, let's arrange the local variables in probe function to follow
reverse XMAS tree order.

Link: https://lore.kernel.org/r/20230316081117.14288-20-manivannan.sadhasivam@linaro.orgSigned-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>