- To avoid bus errors, enable PASID only if entire path supports End-End
    TLP prefixes (Sinan Kaya)

  - Unify slot and bus reset functions and remove hotplug knowledge from
    callers (Sinan Kaya)

  - Add Function-Level Reset quirks for Intel and Samsung NVMe devices to
    fix guest reboot issues (Alex Williamson)

  - Add function 1 DMA alias quirk for Marvell 88SS9183 PCIe SSD Controller
    (Bjorn Helgaas)

* pci/virtualization:
  PCI: Add function 1 DMA alias quirk for Marvell 88SS9183
  PCI: Delay after FLR of Intel DC P3700 NVMe
  PCI: Disable Samsung SM961/PM961 NVMe before FLR
  PCI: Export pcie_has_flr()
  PCI: Rename pci_try_reset_bus() to pci_reset_bus()
  PCI: Deprecate pci_reset_bus() and pci_reset_slot() functions
  PCI: Unify try slot and bus reset API
  PCI: Hide pci_reset_bridge_secondary_bus() from drivers
  IB/hfi1: Use pci_try_reset_bus() for initiating PCI Secondary Bus Reset
  PCI: Handle error return from pci_reset_bridge_secondary_bus()
  PCI/IOV: Tidy pci_sriov_set_totalvfs()
  PCI: Enable PASID only if entire path supports End-End TLP prefixes

# Conflicts:
#	drivers/pci/hotplug/pciehp_hpc.c

  - Mark fall-through switch cases before enabling -Wimplicit-fallthrough
    (Gustavo A. R. Silva)

  - Move DMA-debug PCI init from arch code to PCI core (Christoph Hellwig)

  - Fix pci_request_irq() usage of IRQF_ONESHOT when no handler is supplied
    (Heiner Kallweit)

  - Unify PCI and DMA direction #defines (Shunyong Yang)

  - Add PCI_DEVICE_DATA() macro (Andy Shevchenko)

  - Check for VPD completion before checking for timeout (Bert Kenward)

  - Limit Netronome NFP5000 config space size to work around erratum (Jakub
    Kicinski)

* pci/misc:
  PCI: Limit config space size for Netronome NFP5000
  PCI/VPD: Check for VPD access completion before checking for timeout
  PCI: Add PCI_DEVICE_DATA() macro to fully describe device ID entry
  PCI: Unify PCI and normal DMA direction definitions
  PCI: Use IRQF_ONESHOT if pci_request_irq() called with no handler
  PCI: Call dma_debug_add_bus() for pci_bus_type from PCI core
  PCI: Mark fall-through switch cases before enabling -Wimplicit-fallthrough

# Conflicts:
#	drivers/pci/hotplug/pciehp_ctrl.c

  - Simplify SHPC existence/permission checks (Bjorn Helgaas)

  - Remove hotplug sample skeleton driver (Lukas Wunner)

  - Convert pciehp to threaded IRQ handling (Lukas Wunner)

  - Improve pciehp tolerance of missed events and initially unstable links
    (Lukas Wunner)

  - Clear spurious pciehp events on resume (Lukas Wunner)

  - Add pciehp runtime PM support, including for Thunderbolt controllers
    (Lukas Wunner)

  - Support interrupts from pciehp bridges in D3hot (Lukas Wunner)

* pci/hotplug:
  PCI: pciehp: Deduplicate presence check on probe & resume
  PCI: pciehp: Avoid implicit fallthroughs in switch statements
  PCI: Whitelist Thunderbolt ports for runtime D3
  PCI: Whitelist native hotplug ports for runtime D3
  PCI: sysfs: Resume to D0 on function reset
  PCI: pciehp: Resume parent to D0 on config space access
  PCI: pciehp: Resume to D0 on enable/disable
  PCI: pciehp: Support interrupts sent from D3hot
  PCI: pciehp: Obey compulsory command delay after resume
  PCI: pciehp: Clear spurious events earlier on resume
  PCI: portdrv: Deduplicate PM callback iterator
  PCI: pciehp: Avoid slot access during reset
  PCI: pciehp: Always enable occupied slot on probe
  PCI: pciehp: Become resilient to missed events
  PCI: pciehp: Tolerate initially unstable link
  PCI: pciehp: Declare pciehp_enable/disable_slot() static
  PCI: pciehp: Drop enable/disable lock
  PCI: pciehp: Enable/disable exclusively from IRQ thread
  PCI: pciehp: Track enable/disable status
  PCI: pciehp: Publish to user space last on probe
  PCI: hotplug: Demidlayer registration with the core
  PCI: pciehp: Drop slot workqueue
  PCI: pciehp: Handle events synchronously
  PCI: pciehp: Stop blinking on slot enable failure
  PCI: pciehp: Convert to threaded polling
  PCI: pciehp: Convert to threaded IRQ
  PCI: pciehp: Document struct slot and struct controller
  PCI: pciehp: Declare pciehp_unconfigure_device() void
  PCI: pciehp: Drop unnecessary NULL pointer check
  PCI: pciehp: Fix unprotected list iteration in IRQ handler
  PCI: pciehp: Fix use-after-free on unplug
  PCI: hotplug: Don't leak pci_slot on registration failure
  PCI: hotplug: Delete skeleton driver
  PCI: shpchp: Separate existence of SHPC and permission to use it

On driver probe and on resume from system sleep, pciehp checks the
Presence Detect State bit in the Slot Status register to bring up an
occupied slot or bring down an unoccupied slot.  Both code paths are
identical, so deduplicate them per Mika's request.

On probe, an additional check is performed to disable power of an
unoccupied slot.  This can e.g. happen if power was enabled by BIOS.
It cannot happen once pciehp has taken control, hence is not necessary
on resume:  The Slot Control register is set to the same value that it
had on suspend by pci_restore_state(), so if the slot was occupied,
power is enabled and if it wasn't, power is disabled.  Should occupancy
have changed during the system sleep transition, power is adjusted by
bringing up or down the slot per the paragraph above.

To allow for deduplication of the presence check, move the power check
to pcie_init().  This seems safer anyway, because right now it is
performed while interrupts are already enabled, and although I can't
think of a scenario where pciehp_power_off_slot() and the IRQ thread
collide, it does feel brittle.

However this means that pcie_init() may now write to the Slot Control
register before the IRQ is requested.  If both the CCIE and HPIE bits
happen to be set, pcie_wait_cmd() will wait for an interrupt (instead
of polling the Command Completed bit) and eventually emit a timeout
message.  Additionally, if a level-triggered INTx interrupt is used,
the user may see a spurious interrupt splat.  Avoid by disabling
interrupts before disabling power.  (Normally the HPIE and CCIE bits
should be clear on probe, but conceivably they may already have been
set e.g. by BIOS.)

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Per Mika's request, add an explicit break to the last case of switch
statements everywhere in pciehp to be more defensive towards future
amendments.

Per Gustavo's request, mark all non-empty implicit fallthroughs with a
comment to silence warnings triggered by -Wimplicit-fallthrough=2.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

When a PCI device is detected, pdev->is_added is set to 1 and proc and
sysfs entries are created.

When the device is removed, pdev->is_added is checked for one and then
device is detached with clearing of proc and sys entries and at end,
pdev->is_added is set to 0.

is_added and is_busmaster are bit fields in pci_dev structure sharing same
memory location.

A strange issue was observed with multiple removal and rescan of a PCIe
NVMe device using sysfs commands where is_added flag was observed as zero
instead of one while removing device and proc,sys entries are not cleared.
This causes issue in later device addition with warning message
"proc_dir_entry" already registered.

Debugging revealed a race condition between the PCI core setting the
is_added bit in pci_bus_add_device() and the NVMe driver reset work-queue
setting the is_busmaster bit in pci_set_master().  As these fields are not
handled atomically, that clears the is_added bit.

Move the is_added bit to a separate private flag variable and use atomic
functions to set and retrieve the device addition state.  This avoids the
race because is_added no longer shares a memory location with is_busmaster.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=200283
Signed-off-by: Hari Vyas <hari.vyas@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>

Ensure accessibility of a hotplug port's config space when accessed via
sysfs by resuming its parent to D0.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>

pciehp's IRQ thread ensures accessibility of the port by runtime resuming
its parent to D0.  However when the slot is enabled/disabled, the port
itself needs to be in D0 because its secondary bus is accessed in:

    pciehp_check_link_status(),
    pciehp_configure_device() (both called from board_added())
and
    pciehp_unconfigure_device() (called from remove_board()).

Thus, acquire a runtime PM ref on enable/disablement of the slot.

Yinghai Lu additionally discovered that some SkyLake servers feature a
Power Controller for their PCIe hotplug ports (PCIe r3.1, sec 6.7.1.8)
which requires the port to be in D0 when invoking

    pciehp_power_on_slot() (likewise called from board_added()).

If slot power is turned on while in D3hot, link training later fails:
https://lkml.kernel.org/r/20170205073454.GA253@wunner.de

The spec is silent about such a requirement, but it seems prudent to
assume that any hotplug port with a Power Controller may need this.

The present commit holds a runtime PM ref whenever slot power is turned
on and off, but it doesn't keep the port in D0 as long as slot power is
on.  If vendors determine that's necessary, they need to amend pciehp to
acquire a runtime PM ref in pciehp_power_on_slot() and release one in
pciehp_power_off_slot().

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>

If a hotplug port is able to send an interrupt, one would naively assume
that it is accessible at that moment.  After all, if it wouldn't be
accessible, i.e. if its parent is in D3hot and the link to the hotplug
port is thus down, how should an interrupt come through?

It turns out that assumption is wrong at least for Thunderbolt:  Even
though its parents are in D3hot, a Thunderbolt hotplug port is able to
signal interrupts.  Because the port's config space is inaccessible and
resuming the parents may sleep, the hard IRQ handler has to defer
runtime resuming the parents and reading the Slot Status register to the
IRQ thread.

If the hotplug port uses a level-triggered INTx interrupt, it needs to
be masked until the IRQ thread has cleared the signaled events.  For
simplicity, this commit also masks edge-triggered MSI/MSI-X interrupts.
Note that if the interrupt is shared (which can only happen for INTx),
other devices are starved from receiving interrupts until the IRQ thread
is scheduled, has runtime resumed the hotplug port's parents and has
read and cleared the Slot Status register.

That delay is dominated by the 10 ms D3hot->D0 transition time of each
parent port.  The worst case is a Thunderbolt downstream port at the
end of a daisy chain:  There may be up to six Thunderbolt controllers
in-between it and the root port, each comprising an upstream and
downstream port, plus its own upstream port.  That's 13 x 10 = 130 ms.
Possible mitigations are polling the interrupt while it's disabled or
reducing the d3_delay of Thunderbolt ports if possible.

Open code masking of the interrupt instead of requesting it with the
IRQF_ONESHOT flag to minimize the period during which it is masked.
(IRQF_ONESHOT unmasks the IRQ only after the IRQ thread has finished.)

PCIe r4.0 sec 6.7.3.4 states that "If wake generation is required by the
associated form factor specification, a hotplug capable Downstream Port
must support generation of a wakeup event (using the PME mechanism) on
hotplug events that occur when the system is in a sleep state or the
Port is in device state D1, D2, or D3Hot."

This would seem to imply that PME needs to be enabled on the hotplug
port when it is runtime suspended.  pci_enable_wake() currently doesn't
enable PME on bridges, it may be necessary to add an exemption for
hotplug bridges there.  On "Light Ridge" Thunderbolt controllers, the
PME_Status bit is not set when an interrupt occurs while the hotplug
port is in D3hot, even if PME is enabled.  (I've tested this on a Mac
and we hardcode the OSC_PCI_EXPRESS_PME_CONTROL bit to 0 on Macs in
negotiate_os_control(), modifying it to 1 didn't change the behavior.)

(Side note:  Section 6.7.3.4 also states that "PME and Hot-Plug Event
interrupts (when both are implemented) always share the same MSI or
MSI-X vector".  That would only seem to apply to Root Ports, however
the section never mentions Root Ports, only Downstream Ports.  This is
explained in the definition of "Downstream Port" in the "Terms and
Acronyms" section of the PCIe Base Spec:  "The Ports on a Switch that
are not the Upstream Port are Downstream Ports.  All Ports on a Root
Complex are Downstream Ports.")

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>

Upon resume from system sleep, the Slot Control register is written via:

  pci_pm_resume_noirq()
    pci_pm_default_resume_early()
      pci_restore_state()
        pci_restore_pcie_state()

PCIe r4.0, sec 6.7.3.2 says that after "issuing a write transaction that
targets any portion of the Port's Slot Control register, [...] software
must wait for [the] command to complete before issuing the next command".

pciehp currently fails to enforce that rule after the above-mentioned
write.  Fix it.

(Moving restoration of the Slot Control register to pciehp doesn't seem
to make sense because the other PCIe hotplug drivers may need it as
well.)

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>