- Fix kernel-doc formatting errors (Krzysztof Wilczyński)

* pci/kernel-doc:
  PCI: Fix kernel-doc formatting

- Fix dsm_label_utf16s_to_utf8s() buffer overrun (Krzysztof Wilczyński)

- Use sysfs_emit() and sysfs_emit_at() in "show" functions (Krzysztof
  Wilczyński)

- Fix 'resource_alignment' newline issues (Krzysztof Wilczyński)

- Add newline to 'devspec' sysfs file (Krzysztof Wilczyński)

* pci/sysfs:
  PCI/sysfs: Add 'devspec' newline
  PCI/sysfs: Fix 'resource_alignment' newline issues
  PCI/sysfs: Use sysfs_emit() and sysfs_emit_at() in "show" functions
  PCI/sysfs: Rely on lengths from scnprintf(), dsm_label_utf16s_to_utf8s()
  PCI/sysfs: Fix dsm_label_utf16s_to_utf8s() buffer overrun

# Conflicts:
#	drivers/pci/p2pdma.c

Fix kernel-doc formatting throughout drivers/pci and related include files.
No change to functionality intended.

Check for warnings:

  $ find include drivers/pci -type f -path "*pci*.[ch]" | xargs scripts/kernel-doc -none

[bhelgaas: squashed to one commit]
Link: https://lore.kernel.org/r/20210509030237.368540-1-kw@linux.com
Link: https://lore.kernel.org/r/20210703151306.1922450-1-kw@linux.com
Link: https://lore.kernel.org/r/20210703151306.1922450-2-kw@linux.com
Link: https://lore.kernel.org/r/20210703151306.1922450-3-kw@linux.com
Link: https://lore.kernel.org/r/20210703151306.1922450-4-kw@linux.com
Link: https://lore.kernel.org/r/20210703151306.1922450-5-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

cpci_debug is declared as a global variable in cpci_hotplug_core.c and used
in cpci_hotplug_pci.c via an "extern".  Add an extern declaration in the
header file.

Resolves the following sparse warning:

  drivers/pci/hotplug/cpci_hotplug_core.c:47:5: warning: symbol 'cpci_debug' was not declared. Should it be static?

Link: https://lore.kernel.org/r/20210701184306.1492003-1-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Downstream Port Containment (PCIe r5.0, sec. 6.2.10) disables the link upon
an error and attempts to re-enable it when instructed by the DPC driver.

A slot which is both DPC- and hotplug-capable is currently powered off by
pciehp once DPC is triggered (due to the link change) and powered back up
on successful recovery.  That's undesirable, the slot should remain powered
so the hotplugged device remains bound to its driver.  DPC notifies the
driver of the error and of successful recovery in pcie_do_recovery() and
the driver may then restore the device to working state.

Moreover, Sinan points out that turning off slot power by pciehp may foil
recovery by DPC:  Power off/on is a cold reset concurrently to DPC's warm
reset.  Sathyanarayanan reports extended delays or failure in link
retraining by DPC if pciehp brings down the slot.

Fix by detecting whether a Link Down event is caused by DPC and awaiting
recovery if so.  On successful recovery, ignore both the Link Down and the
subsequent Link Up event.

Afterwards, check whether the link is down to detect surprise-removal or
another DPC event immediately after DPC recovery.  Ensure that the
corresponding DLLSC event is not ignored by synthesizing it and invoking
irq_wake_thread() to trigger a re-run of pciehp_ist().

The IRQ threads of the hotplug and DPC drivers, pciehp_ist() and
dpc_handler(), race against each other.  If pciehp is faster than DPC, it
will wait until DPC recovery completes.

Recovery consists of two steps:  The first step (waiting for link
disablement) is recognizable by pciehp through a set DPC Trigger Status
bit.  The second step (waiting for link retraining) is recognizable through
a newly introduced PCI_DPC_RECOVERING flag.

If DPC is faster than pciehp, neither of the two flags will be set and
pciehp may glean the recovery status from the new PCI_DPC_RECOVERED flag.
The flag is zero if DPC didn't occur at all, hence DLLSC events are not
ignored by default.

pciehp waits up to 4 seconds before assuming that DPC recovery failed and
bringing down the slot.  This timeout is not taken from the spec (it
doesn't mandate one) but based on a report from Yicong Yang that DPC may
take a bit more than 3 seconds on HiSilicon's Kunpeng platform.

The timeout is necessary because the DPC Trigger Status bit may never
clear:  On Root Ports which support RP Extensions for DPC, the DPC driver
polls the DPC RP Busy bit for up to 1 second before giving up on DPC
recovery.  Without the timeout, pciehp would then wait indefinitely for DPC
to complete.

This commit draws inspiration from previous attempts to synchronize DPC
with pciehp:

By Sinan Kaya, August 2018:
https://lore.kernel.org/linux-pci/20180818065126.77912-1-okaya@kernel.org/

By Ethan Zhao, October 2020:
https://lore.kernel.org/linux-pci/20201007113158.48933-1-haifeng.zhao@intel.com/

By Kuppuswamy Sathyanarayanan, March 2021:
https://lore.kernel.org/linux-pci/59cb30f5e5ac6d65427ceaadf1012b2ba8dbf66c.1615606143.git.sathyanarayanan.kuppuswamy@linux.intel.com/

Link: https://lore.kernel.org/r/0be565d97438fe2a6d57354b3aa4e8626952a00b.1619857124.git.lukas@wunner.de
Reported-by: Sinan Kaya <okaya@kernel.org>
Reported-by: Ethan Zhao <haifeng.zhao@intel.com>
Reported-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Tested-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Tested-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Keith Busch <kbusch@kernel.org>

The sysfs_emit() and sysfs_emit_at() functions were introduced to make
it less ambiguous which function is preferred when writing to the output
buffer in a device attribute's "show" callback [1].

Convert the PCI sysfs object "show" functions from sprintf(), snprintf()
and scnprintf() to sysfs_emit() and sysfs_emit_at() accordingly, as the
latter is aware of the PAGE_SIZE buffer and correctly returns the number
of bytes written into the buffer.

No functional change intended.

[1] Documentation/filesystems/sysfs.rst

Related commit: ad025f8e46f3 ("PCI/sysfs: Use sysfs_emit() and
sysfs_emit_at() in "show" functions").

Link: https://lore.kernel.org/r/20210603000112.703037-2-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>

Pull more s390 updates from Heiko Carstens:

 - add support for system call stack randomization

 - handle stale PCI deconfiguration events

 - couple of defconfig updates

 - some fixes and cleanups

* tag 's390-5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390: fix detection of vector enhancements facility 1 vs. vector packed decimal facility
  s390/entry: add support for syscall stack randomization
  s390/configs: change CONFIG_VIRTIO_CONSOLE to "m"
  s390/cio: remove invalid condition on IO_SCH_UNREG
  s390/cpumf: remove call to perf_event_update_userpage
  s390/cpumf: move counter set size calculation to common place
  s390/cpumf: beautify if-then-else indentation
  s390/configs: enable CONFIG_PCI_IOV
  s390/pci: handle stale deconfiguration events
  s390/pci: rename zpci_configure_device()

Pull pci updates from Bjorn Helgaas:
 "Enumeration:
   - Release OF node when pci_scan_device() fails (Dmitry Baryshkov)
   - Add pci_disable_parity() (Bjorn Helgaas)
   - Disable Mellanox Tavor parity reporting (Heiner Kallweit)
   - Disable N2100 r8169 parity reporting (Heiner Kallweit)
   - Fix RCiEP device to RCEC association (Qiuxu Zhuo)
   - Convert sysfs "config", "rom", "reset", "label", "index",
     "acpi_index" to static attributes to help fix races in device
     enumeration (Krzysztof Wilczyński)
   - Convert sysfs "vpd" to static attribute (Heiner Kallweit, Krzysztof
     Wilczyński)
   - Use sysfs_emit() in "show" functions (Krzysztof Wilczyński)
   - Remove unused alloc_pci_root_info() return value (Krzysztof
     Wilczyński)

  PCI device hotplug:
   - Fix acpiphp reference count leak (Feilong Lin)

  Power management:
   - Fix acpi_pci_set_power_state() debug message (Rafael J. Wysocki)
   - Fix runtime PM imbalance (Dinghao Liu)

  Virtualization:
   - Increase delay after FLR to work around Intel DC P4510 NVMe erratum
     (Raphael Norwitz)

  MSI:
   - Convert rcar, tegra, xilinx to MSI domains (Marc Zyngier)
   - For rcar, xilinx, use controller address as MSI doorbell (Marc
     Zyngier)
   - Remove unused hv msi_controller struct (Marc Zyngier)
   - Remove unused PCI core msi_controller support (Marc Zyngier)
   - Remove struct msi_controller altogether (Marc Zyngier)
   - Remove unused default_teardown_msi_irqs() (Marc Zyngier)
   - Let host bridges declare their reliance on MSI domains (Marc
     Zyngier)
   - Make pci_host_common_probe() declare its reliance on MSI domains
     (Marc Zyngier)
   - Advertise mediatek lack of built-in MSI handling (Thomas Gleixner)
   - Document ways of ending up with NO_MSI (Marc Zyngier)
   - Refactor HT advertising of NO_MSI flag (Marc Zyngier)

  VPD:
   - Remove obsolete Broadcom NIC VPD length-limiting quirk (Heiner
     Kallweit)
   - Remove sysfs VPD size checking dead code (Heiner Kallweit)
   - Convert VPF sysfs file to static attribute (Heiner Kallweit)
   - Remove unnecessary pci_set_vpd_size() (Heiner Kallweit)
   - Tone down "missing VPD" message (Heiner Kallweit)

  Endpoint framework:
   - Fix NULL pointer dereference when epc_features not implemented
     (Shradha Todi)
   - Add missing destroy_workqueue() in endpoint test (Yang Yingliang)

  Amazon Annapurna Labs PCIe controller driver:
   - Fix compile testing without CONFIG_PCI_ECAM (Arnd Bergmann)
   - Fix "no symbols" warnings when compile testing with
     CONFIG_TRIM_UNUSED_KSYMS (Arnd Bergmann)

  APM X-Gene PCIe controller driver:
   - Fix cfg resource mapping regression (Dejin Zheng)

  Broadcom iProc PCIe controller driver:
   - Return zero for success of iproc_msi_irq_domain_alloc() (Pali
     Rohár)

  Broadcom STB PCIe controller driver:
   - Add reset_control_rearm() stub for !CONFIG_RESET_CONTROLLER (Jim
     Quinlan)
   - Fix use of BCM7216 reset controller (Jim Quinlan)
   - Use reset/rearm for Broadcom STB pulse reset instead of
     deassert/assert (Jim Quinlan)
   - Fix brcm_pcie_probe() error return for unsupported revision (Wei
     Yongjun)

  Cavium ThunderX PCIe controller driver:
   - Fix compile testing (Arnd Bergmann)
   - Fix "no symbols" warnings when compile testing with
     CONFIG_TRIM_UNUSED_KSYMS (Arnd Bergmann)

  Freescale Layerscape PCIe controller driver:
   - Fix ls_pcie_ep_probe() syntax error (comma for semicolon)
     (Krzysztof Wilczyński)
   - Remove layerscape-gen4 dependencies on OF and ARM64, add dependency
     on ARCH_LAYERSCAPE (Geert Uytterhoeven)

  HiSilicon HIP PCIe controller driver:
   - Remove obsolete HiSilicon PCIe DT description (Dongdong Liu)

  Intel Gateway PCIe controller driver:
   - Remove unused pcie_app_rd() (Jiapeng Chong)

  Intel VMD host bridge driver:
   - Program IRTE with Requester ID of VMD endpoint, not child device
     (Jon Derrick)
   - Disable VMD MSI-X remapping when possible so children can use more
     MSI-X vectors (Jon Derrick)

  MediaTek PCIe controller driver:
   - Configure FC and FTS for functions other than 0 (Ryder Lee)
   - Add YAML schema for MediaTek (Jianjun Wang)
   - Export pci_pio_to_address() for module use (Jianjun Wang)
   - Add MediaTek MT8192 PCIe controller driver (Jianjun Wang)
   - Add MediaTek MT8192 INTx support (Jianjun Wang)
   - Add MediaTek MT8192 MSI support (Jianjun Wang)
   - Add MediaTek MT8192 system power management support (Jianjun Wang)
   - Add missing MODULE_DEVICE_TABLE (Qiheng Lin)

  Microchip PolarFlare PCIe controller driver:
   - Make several symbols static (Wei Yongjun)

  NVIDIA Tegra PCIe controller driver:
   - Add MCFG quirks for Tegra194 ECAM errata (Vidya Sagar)
   - Make several symbols const (Rikard Falkeborn)
   - Fix Kconfig host/endpoint typo (Wesley Sheng)

  SiFive FU740 PCIe controller driver:
   - Add pcie_aux clock to prci driver (Greentime Hu)
   - Use reset-simple in prci driver for PCIe (Greentime Hu)
   - Add SiFive FU740 PCIe host controller driver and DT binding (Paul
     Walmsley, Greentime Hu)

  Synopsys DesignWare PCIe controller driver:
   - Move MSI Receiver init to dw_pcie_host_init() so it is
     re-initialized along with the RC in resume (Jisheng Zhang)
   - Move iATU detection earlier to fix regression (Hou Zhiqiang)

  TI J721E PCIe driver:
   - Add DT binding and TI j721e support for refclk to PCIe connector
     (Kishon Vijay Abraham I)
   - Add host mode and endpoint mode DT bindings for TI AM64 SoC (Kishon
     Vijay Abraham I)

  TI Keystone PCIe controller driver:
   - Use generic config accessors for TI AM65x (K3) to fix regression
     (Kishon Vijay Abraham I)

  Xilinx NWL PCIe controller driver:
   - Add support for coherent PCIe DMA traffic using CCI (Bharat Kumar
     Gogada)
   - Add optional "dma-coherent" DT property (Bharat Kumar Gogada)

  Miscellaneous:
   - Fix kernel-doc warnings (Krzysztof Wilczyński)
   - Remove unused MicroGate SyncLink device IDs (Jiri Slaby)
   - Remove redundant dev_err() for devm_ioremap_resource() failure
     (Chen Hui)
   - Remove redundant initialization (Colin Ian King)
   - Drop redundant dev_err() for platform_get_irq() errors (Krzysztof
     Wilczyński)"

* tag 'pci-v5.13-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (98 commits)
  riscv: dts: Add PCIe support for the SiFive FU740-C000 SoC
  PCI: fu740: Add SiFive FU740 PCIe host controller driver
  dt-bindings: PCI: Add SiFive FU740 PCIe host controller
  MAINTAINERS: Add maintainers for SiFive FU740 PCIe driver
  clk: sifive: Use reset-simple in prci driver for PCIe driver
  clk: sifive: Add pcie_aux clock in prci driver for PCIe driver
  PCI: brcmstb: Use reset/rearm instead of deassert/assert
  ata: ahci_brcm: Fix use of BCM7216 reset controller
  reset: add missing empty function reset_control_rearm()
  PCI: Allow VPD access for QLogic ISP2722
  PCI/VPD: Add helper pci_get_func0_dev()
  PCI/VPD: Remove pci_vpd_find_tag() SRDT handling
  PCI/VPD: Remove pci_vpd_find_tag() 'offset' argument
  PCI/VPD: Change pci_vpd_init() return type to void
  PCI/VPD: Make missing VPD message less alarming
  PCI/VPD: Remove pci_set_vpd_size()
  x86/PCI: Remove unused alloc_pci_root_info() return value
  MAINTAINERS: Add Jianjun Wang as MediaTek PCI co-maintainer
  PCI: mediatek-gen3: Add system PM support
  PCI: mediatek-gen3: Add MSI support
  ...

- Fix kernel-doc warnings (Krzysztof Wilczyński)

* pci/kernel-doc:
  PCI: Fix kernel-doc errors

With zpci_configure_device() now always called on a device that has
already been configured on the platform level its name has become
misleading. Rename it to zpci_scan_configured_device() to signify that
the function now only handles the correct scanning of a newly configured
PCI function taking care of the special handling necessary for function
0 and functions parked waiting for a PCI bus that can't be created
without first seeing function 0.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>