There are some cases where a SR-IOV VF driver will need to reach into and
interact with the PF driver. This requires accessing the drvdata of the PF.

Provide a function pci_iov_get_pf_drvdata() to return this PF drvdata in a
safe way. Normally accessing a drvdata of a foreign struct device would be
done using the device_lock() to protect against device driver
probe()/remove() races.

However, due to the design of pci_enable_sriov() this will result in a
ABBA deadlock on the device_lock as the PF's device_lock is held during PF
sriov_configure() while calling pci_enable_sriov() which in turn holds the
VF's device_lock while calling VF probe(), and similarly for remove.

This means the VF driver can never obtain the PF's device_lock.

Instead use the implicit locking created by pci_enable/disable_sriov(). A
VF driver can access its PF drvdata only while its own driver is attached,
and the PF driver can control access to its own drvdata based on when it
calls pci_enable/disable_sriov().

To use this API the PF driver will setup the PF drvdata in the probe()
function. pci_enable_sriov() is only called from sriov_configure() which
cannot happen until probe() completes, ensuring no VF races with drvdata
setup.

For removal, the PF driver must call pci_disable_sriov() in its remove
function before destroying any of the drvdata. This ensures that all VF
drivers are unbound before returning, fencing concurrent access to the
drvdata.

The introduction of a new function to do this access makes clear the
special locking scheme and the documents the requirements on the PF/VF
drivers using this.

Link: https://lore.kernel.org/all/20220224142024.147653-5-yishaih@nvidia.comSigned-off-by: NJason Gunthorpe <jgg@nvidia.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NYishai Hadas <yishaih@nvidia.com>
Signed-off-by: NLeon Romanovsky <leonro@nvidia.com>

The PCI core uses the VF index internally, often called the vf_id,
during the setup of the VF, eg pci_iov_add_virtfn().

This index is needed for device drivers that implement live migration
for their internal operations that configure/control their VFs.

Specifically, mlx5_vfio_pci driver that is introduced in coming patches
from this series needs it and not the bus/device/function which is
exposed today.

Add pci_iov_vf_id() which computes the vf_id by reversing the math that
was used to create the bus/device/function.

Link: https://lore.kernel.org/all/20220224142024.147653-2-yishaih@nvidia.comSigned-off-by: NJason Gunthorpe <jgg@nvidia.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NYishai Hadas <yishaih@nvidia.com>
Signed-off-by: NLeon Romanovsky <leonro@nvidia.com>

Per PCIe r5, sec 7.5.1.2.4, a device must not claim accesses to its
Expansion ROM unless both the Memory Space Enable and the Expansion ROM
Enable bit are set.  But apparently some Intel I210 NICs don't work
correctly if the ROM BAR overlaps another BAR, even if the Expansion ROM is
disabled.

Michael reported that on a Kontron SMARC-sAL28 ARM64 system with U-Boot
v2021.01-rc3, the ROM BAR overlaps BAR 3, and networking doesn't work at
all:

  BAR 0: 0x40000000 (32-bit, non-prefetchable) [size=1M]
  BAR 3: 0x40200000 (32-bit, non-prefetchable) [size=16K]
  ROM:   0x40200000 (disabled) [size=1M]

  NETDEV WATCHDOG: enP2p1s0 (igb): transmit queue 0 timed out
  Hardware name: Kontron SMARC-sAL28 (Single PHY) on SMARC Eval 2.0 carrier (DT)
  igb 0002:01:00.0 enP2p1s0: Reset adapter

Previously, pci_std_update_resource() wrote the assigned ROM address to the
BAR only when the ROM was enabled.  This meant that the I210 ROM BAR could
be left with an address assigned by firmware, which might overlap with
other BARs.

Quirk these I210 devices so pci_std_update_resource() always writes the
assigned address to the ROM BAR, whether or not the ROM is enabled.

Link: https://lore.kernel.org/r/20211223163754.GA1267351@bhelgaas
Link: https://lore.kernel.org/r/20201230185317.30915-1-michael@walle.cc
Link: https://bugzilla.kernel.org/show_bug.cgi?id=211105Reported-by: NMichael Walle <michael@walle.cc>
Tested-by: NMichael Walle <michael@walle.cc>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Change the pci_dev_present() stub which is used when CONFIG_PCI is not set
from a #define to a static inline stub.

Thix should fix clang -Werror builds failing due to errors like this:

  drivers/platform/x86/thinkpad_acpi.c:4475:35:
   error: unused variable 'fwbug_cards_ids' [-Werror,-Wunused-const-variable]

Where fwbug_cards_ids is an array of pci_device_id passed to
pci_dev_present() during a quirk check.

Link: https://lore.kernel.org/r/20211217141515.379586-1-hdegoede@redhat.comReported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Cc: platform-driver-x86@vger.kernel.org

Set the domain info flag which makes the core code handle sysfs groups and
put an explicit invocation into the legacy code.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NMichael Kelley <mikelley@microsoft.com>
Tested-by: NNishanth Menon <nm@ti.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NJason Gunthorpe <jgg@nvidia.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20211210221814.048612053@linutronix.de

The MSI core will introduce runtime allocation of MSI related data. This
data will be devres managed and has to be set up before enabling
PCI/MSI[-X]. This would introduce an ordering issue vs. pcim_release().

The setup order is:

   pcim_enable_device()
	devres_alloc(pcim_release...);
	...
	pci_irq_alloc()
	  msi_setup_device_data()
	     devres_alloc(msi_device_data_release, ...)

and once the device is released these release functions are invoked in the
opposite order:

    msi_device_data_release()
    ...
    pcim_release()
       pci_disable_msi[x]()

which is obviously wrong, because pci_disable_msi[x]() requires the MSI
data to be available to tear down the MSI[-X] interrupts.

Remove the MSI[-X] teardown from pcim_release() and add an explicit action
to be installed on the attempt of enabling PCI/MSI[-X].

This allows the MSI core data allocation to be ordered correctly in a
subsequent step.
Reported-by: NNishanth Menon <nm@ti.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NMichael Kelley <mikelley@microsoft.com>
Tested-by: NNishanth Menon <nm@ti.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/87tuf9rdoj.ffs@tglx

It's only required for PCI/MSI. So no point in having it in every struct
device.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NJason Gunthorpe <jgg@nvidia.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20211206210224.925241961@linutronix.de

Unmapping the MSI-X base mapping in the loops which allocate/free MSI
descriptors is daft and in the way of allowing runtime expansion of MSI-X
descriptors.

Store the mapping in struct pci_dev and free it after freeing the MSI-X
descriptors.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NJason Gunthorpe <jgg@nvidia.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20211206210224.871651518@linutronix.de

A config or MMIO read from a PCI device that doesn't exist or doesn't
respond causes a PCI error. There's no real data to return to satisfy the
CPU read, so most hardware fabricates ~0 data.

Add a PCI_ERROR_RESPONSE definition for that and use it where appropriate
to make these checks consistent and easier to find.

Also add helper definitions PCI_SET_ERROR_RESPONSE() and
PCI_POSSIBLE_ERROR() to make the code more readable.
Suggested-by: NBjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/55563bf4dfc5d3fdc96695373c659d099bf175b1.1637243717.git.naveennaidu479@gmail.comSigned-off-by: NNaveen Naidu <naveennaidu479@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NPali Rohár <pali@kernel.org>

This reverts commit b5f9c644.

Revert b5f9c644 ("PCI: Remove struct pci_dev->driver"), which is needed
to revert 2a4d9408 ("PCI: Use to_pci_driver() instead of
pci_dev->driver").

2a4d9408 caused a NULL pointer dereference reported by Robert Święcki.
Details in the revert of that commit.

Fixes: 2a4d9408 ("PCI: Use to_pci_driver() instead of pci_dev->driver")
Link: https://lore.kernel.org/linux-i2c/CAP145pgdrdiMAT7=-iB1DMgA7t_bMqTcJL4N0=6u8kNY3EU0dw@mail.gmail.com/Reported-by: NRobert Święcki <robert@swiecki.net>
Tested-by: NRobert Święcki <robert@swiecki.net>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

It appears that some devices are lying about their mask capability,
pretending that they don't have it, while they actually do.
The net result is that now that we don't enable MSIs on such
endpoint.

Add a new per-device flag to deal with this. Further patches will
make use of it, sadly.
Signed-off-by: NMarc Zyngier <maz@kernel.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20211104180130.3825416-2-maz@kernel.org
Cc: Bjorn Helgaas <helgaas@kernel.org>

Commit e3a9b121 ("PCI: Export pci_dev_trylock() and pci_dev_unlock()")
already exported pci_dev_trylock()/pci_dev_unlock() however in some
circumstances such as during error recovery it makes sense to block
waiting to get full access to the device so also export pci_dev_lock().

Link: https://lore.kernel.org/all/20210928181014.GA713179@bhelgaas/Acked-by: NPierre Morel <pmorel@linux.ibm.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NNiklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: NVasily Gorbik <gor@linux.ibm.com>

Add pci_find_dvsec_capability to locate a Designated Vendor-Specific
Extended Capability with the specified Vendor ID and Capability ID.

The Designated Vendor-Specific Extended Capability (DVSEC) allows one or
more "vendor" specific capabilities that are not tied to the Vendor ID
of the PCI component. Where the DVSEC Vendor may be a standards body
like CXL.

Cc: David E. Box <david.e.box@linux.intel.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: linux-pci@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Andrew Donnellan <ajd@linux.ibm.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: NFrederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: NBen Widawsky <ben.widawsky@intel.com>
Reviewed-by: NAndrew Donnellan <ajd@linux.ibm.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Tested-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Reviewed-by: NJonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/163379787943.692348.6814373487017444007.stgit@dwillia2-desk3.amr.corp.intel.comSigned-off-by: NDan Williams <dan.j.williams@intel.com>

The pci_pool users have been converted to dma_pool.  Remove the unused
pci_pool wrappers.

Link: https://lore.kernel.org/r/20211018124110.214-1-caihuoqing@baidu.comSigned-off-by: NCai Huoqing <caihuoqing@baidu.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

There are no remaining uses of the struct pci_dev->driver pointer, so
remove it.

Link: https://lore.kernel.org/r/20211004125935.2300113-12-u.kleine-koenig@pengutronix.deSigned-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

to_pci_driver() takes a pointer to a struct device_driver and uses
container_of() to find the struct pci_driver that contains it.

If given a NULL pointer to a struct device_driver, return a NULL pci_driver
pointer instead of applying container_of() to NULL.

This simplifies callers that would otherwise have to check for a NULL
pointer first.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

In certain cases we need a variant of pci_read_vpd()/pci_write_vpd() that
does not check against dev->vpd.len. Such cases are:

  - Reading VPD if dev->vpd.len isn't set yet (in pci_vpd_size())

  - Devices that map non-VPD information to arbitrary places in VPD address
    space (example: Chelsio T3 EEPROM write-protect flag)

Therefore add pci_read_vpd_any() and pci_write_vpd_any() that check against
PCI_VPD_MAX_SIZE only.

Link: https://lore.kernel.org/r/93ecce28-a158-f02a-d134-8afcaced8efe@gmail.comSigned-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NJakub Kicinski <kuba@kernel.org>

The general convention for pcibios_* hooks is that they're named after the
corresponding pci_* function they provide a hook for. The exception is
pcibios_add_device() which provides a hook for pci_device_add().

Rename pcibios_add_device() to pcibios_device_add() so it matches
pci_device_add().

Also, remove the export of the microblaze version. The only caller must be
compiled as a built-in so there's no reason for the export.

Link: https://lore.kernel.org/r/20210913152709.48013-1-oohall@gmail.comSigned-off-by: NOliver O'Halloran <oohall@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: Niklas Schnelle <schnelle@linux.ibm.com>	# s390

After recent introduction of new VPD API functions and user migration
these defines and inline functions aren't used outside VPD core any
longer.

Link: https://lore.kernel.org/r/d33e06bf-bc5e-ece7-bf35-7245ae224d1b@gmail.comSigned-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Add a pci_vpd_find_id_string() API function to retrieve the ID string from
VPD.

This way callers don't need pci_vpd_lrdt_size() any longer, and it can be
made private to the VPD core.

Link: https://lore.kernel.org/r/c5225bf6-8d29-970d-e271-0d7b52252630@gmail.comSigned-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Now that the last users have been migrated to pci_vpd_find_ro_keyword()
we can stop exporting this function. It's still used in VPD core code.

Link: https://lore.kernel.org/r/96ca2a56-383e-9b61-9cba-4f1e5611dc15@gmail.comSigned-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Now that the last users have been migrated to pci_vpd_find_ro_keyword()
we can stop exporting this function. It's still used in VPD core code.

Link: https://lore.kernel.org/r/71131eca-0502-7878-365f-30b6614161cf@gmail.comSigned-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Some systems, e.g., HiSilicon KunPeng920 and KunPeng930, have devices that
appear as PCI but are actually on the AMBA bus.  Some of these fake PCI
devices support a PASID-like feature and they do have a working PASID
capability even though they do not use the PCIe Transport Layer Protocol
and do not support TLP prefixes.

Add a pasid_no_tlp bit for this "PASID works without TLP prefixes" case and
update pci_enable_pasid() so it can enable PASID on these devices.

Set this bit for HiSilicon KunPeng920 and KunPeng930.

[bhelgaas: squashed, commit log]
Suggested-by: NBjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/1626144876-11352-2-git-send-email-zhangfei.gao@linaro.org
Link: https://lore.kernel.org/r/1626144876-11352-3-git-send-email-zhangfei.gao@linaro.orgSigned-off-by: NZhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: NJean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: NZhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Expose an 'override_only' helper macro (i.e.
PCI_DRIVER_OVERRIDE_DEVICE_VFIO) for VFIO PCI sub system and add the
required code to prefix its matching entries with "vfio_" in
modules.alias file.

It allows VFIO device drivers to include match entries in the
modules.alias file produced by kbuild that are not used for normal
driver autoprobing and module autoloading. Drivers using these match
entries can be connected to the PCI device manually, by userspace, using
the existing driver_override sysfs.

For example the resulting modules.alias may have:

  alias pci:v000015B3d00001021sv*sd*bc*sc*i* mlx5_core
  alias vfio_pci:v000015B3d00001021sv*sd*bc*sc*i* mlx5_vfio_pci
  alias vfio_pci:v*d*sv*sd*bc*sc*i* vfio_pci

In this example mlx5_core and mlx5_vfio_pci match to the same PCI
device. The kernel will autoload and autobind to mlx5_core but the
kernel and udev mechanisms will ignore mlx5_vfio_pci.

When userspace wants to change a device to the VFIO subsystem it can
implement a generic algorithm:

   1) Identify the sysfs path to the device:
    /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0

   2) Get the modalias string from the kernel:
    $ cat /sys/bus/pci/devices/0000:01:00.0/modalias
    pci:v000015B3d00001021sv000015B3sd00000001bc02sc00i00

   3) Prefix it with vfio_:
    vfio_pci:v000015B3d00001021sv000015B3sd00000001bc02sc00i00

   4) Search modules.alias for the above string and select the entry that
      has the fewest *'s:
    alias vfio_pci:v000015B3d00001021sv*sd*bc*sc*i* mlx5_vfio_pci

   5) modprobe the matched module name:
    $ modprobe mlx5_vfio_pci

   6) cat the matched module name to driver_override:
    echo mlx5_vfio_pci > /sys/bus/pci/devices/0000:01:00.0/driver_override

   7) unbind device from original module
     echo 0000:01:00.0 > /sys/bus/pci/devices/0000:01:00.0/driver/unbind

   8) probe PCI drivers (or explicitly bind to mlx5_vfio_pci)
    echo 0000:01:00.0 > /sys/bus/pci/drivers_probe

The algorithm is independent of bus type. In future the other buses with
VFIO device drivers, like platform and ACPI, can use this algorithm as
well.

This patch is the infrastructure to provide the information in the
modules.alias to userspace. Convert the only VFIO pci_driver which results
in one new line in the modules.alias:

  alias vfio_pci:v*d*sv*sd*bc*sc*i* vfio_pci

Later series introduce additional HW specific VFIO PCI drivers, such as
mlx5_vfio_pci.
Signed-off-by: NMax Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>  # for pci.h
Signed-off-by: NYishai Hadas <yishaih@nvidia.com>
Link: https://lore.kernel.org/r/20210826103912.128972-11-yishaih@nvidia.comSigned-off-by: NAlex Williamson <alex.williamson@redhat.com>

Add 'override_only' field to struct pci_device_id to be used as part of
pci_match_device().

When set, a driver only matches the entry when dev->driver_override is
set to that driver.

In addition, add a helper macro named 'PCI_DEVICE_DRIVER_OVERRIDE' to
enable setting some data on it.

Next patch from this series will use the above functionality.
Signed-off-by: NMax Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NYishai Hadas <yishaih@nvidia.com>
Link: https://lore.kernel.org/r/20210826103912.128972-10-yishaih@nvidia.comSigned-off-by: NAlex Williamson <alex.williamson@redhat.com>

Add a predicate that returns if PCIe PTM (Precision Time Measurement)
is enabled.

It will only return true if it's enabled in all the ports in the path
from the device to the root.
Signed-off-by: NVinicius Costa Gomes <vinicius.gomes@intel.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NTony Nguyen <anthony.l.nguyen@intel.com>

Make pci_enable_ptm() accessible from the drivers.

Exposing this to the driver enables the driver to use the
'ptm_enabled' field of 'pci_dev' to check if PTM is enabled or not.

This reverts commit ac6c26da ("PCI: Make pci_enable_ptm() private").
Signed-off-by: NVinicius Costa Gomes <vinicius.gomes@intel.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NTony Nguyen <anthony.l.nguyen@intel.com>

Currently we retrieve the PCI domain number of the host bridge from the
bus sysdata (or pci_config_window if PCI_DOMAINS_GENERIC=y). Actually
we have the information at PCI host bridge probing time, and it makes
sense that we store it into pci_host_bridge. One benefit of doing so is
the requirement for supporting PCI on Hyper-V for ARM64, because the
host bridge of Hyper-V doesn't have pci_config_window, whereas ARM64 is
a PCI_DOMAINS_GENERIC=y arch, so we cannot retrieve the PCI domain
number from pci_config_window on ARM64 Hyper-V guest.

As the preparation for ARM64 Hyper-V PCI support, we introduce the
domain_nr in pci_host_bridge and a sentinel value to allow drivers to
set domain numbers properly at probing time. Currently
CONFIG_PCI_DOMAINS_GENERIC=y archs are only users of this
newly-introduced field.

Link: https://lore.kernel.org/r/20210726180657.142727-2-boqun.feng@gmail.comSigned-off-by: NBoqun Feng <boqun.feng@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>

The CONFIG_PCI=y case got a new parameter long time ago.  Sync the stub as
well.

[bhelgaas: add parameter names]
Fixes: 725522b5 ("PCI: add the sysfs driver name to all modules")
Link: https://lore.kernel.org/r/20210813153619.89574-1-andriy.shevchenko@linux.intel.comReported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

pci_resource_end() can be 0 only when pci_resource_start() is 0.
Otherwise, it is definitely an error. In this case, pci_resource_len()
should be regarded as 0. Therefore, determining whether
pci_resource_start() and pci_resource_end() are both 0 can be reduced to
determining only whether pci_resource_end() is 0.

Although only one condition judgment is reduced, the macro function
pci_resource_len() is widely referenced in the kernel. I used defconfig to
compile the latest kernel on X86, and its binary code size was reduced by
about 3KB.

  Before:
   [ 2] .rela.text        RELA             0000000000000000  093bfcb0
        0000000001a67168  0000000000000018   I      68     1     8

  After:
   [ 2] .rela.text        RELA             0000000000000000  093bfcb0
        0000000001a66598  0000000000000018   I      68     1     8

Link: https://lore.kernel.org/r/20210713072236.3043-1-thunder.leizhen@huawei.comSigned-off-by: NZhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Interfaces and structs for saving and restoring PCI Capability state were
declared in include/linux/pci.h, but aren't needed outside drivers/pci/.

Move these to drivers/pci/pci.h:

  struct pci_cap_saved_data
  struct pci_cap_saved_state
  void pci_allocate_cap_save_buffers()
  void pci_free_cap_save_buffers()
  int pci_add_cap_save_buffer()
  int pci_add_ext_cap_save_buffer()
  struct pci_cap_saved_state *pci_find_saved_cap()
  struct pci_cap_saved_state *pci_find_saved_ext_cap()

Link: https://lore.kernel.org/r/20210802221728.1469304-1-helgaas@kernel.orgSigned-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NAlex Williamson <alex.williamson@redhat.com>

VPD checksum information and checksum calculation are specified by PCIe
r5.0, sec 6.28.2.2.  Therefore checksum handling can and should be moved
into the PCI VPD core.

Add pci_vpd_check_csum() to validate the VPD checksum.

[bhelgaas: split to separate patch]
Link: https://lore.kernel.org/r/1643bd7a-088e-1028-c9b0-9d112cf48d63@gmail.comSigned-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

All users of pci_vpd_find_info_keyword() are interested in the VPD RO
section only. In addition all calls are followed by the same activities to
calculate start of tag data area and size of the data area.

Add pci_vpd_find_ro_info_keyword() that combines these functionalities.

pci_vpd_find_info_keyword() can be phased out once all users are converted.

[bhelgaas: split pci_vpd_check_csum() to separate patch]
Link: https://lore.kernel.org/r/1643bd7a-088e-1028-c9b0-9d112cf48d63@gmail.comSigned-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Several users of the VPD API use a fixed-size buffer and read the VPD into
it for further usage. This requires special handling for the case that the
buffer isn't big enough to hold the full VPD data.  Also the buffer is
often allocated on the stack, which isn't too nice.

Add pci_vpd_alloc() to dynamically allocate buffer of the correct size and
read VPD into it.

Link: https://lore.kernel.org/r/955ff598-0021-8446-f856-0c2c077635d7@gmail.comSigned-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Change the type of probe argument in functions which implement reset
methods from int to bool to make the context and intent clear.
Suggested-by: NAlex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20210817180500.1253-10-ameynarkhede03@gmail.comSigned-off-by: NAmey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

_RST is a standard ACPI method that performs a function level reset of a
device (ACPI v6.3, sec 7.3.25).

Add pci_dev_acpi_reset() to probe for _RST method and execute if present.
The default priority of this reset is set to below device-specific and
above hardware resets.
Suggested-by: NAlex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20210817180500.1253-9-ameynarkhede03@gmail.comSigned-off-by: NShanker Donthineni <sdonthineni@nvidia.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NSinan Kaya <okaya@kernel.org>
Reviewed-by: NAlex Williamson <alex.williamson@redhat.com>

"reset_fn" indicates whether the device supports any reset mechanism.
Remove the use of reset_fn in favor of the reset_methods array that tracks
supported reset mechanisms of a device and their ordering.

The octeon driver incorrectly used reset_fn to detect whether the device
supports FLR or not. Use pcie_reset_flr() to probe whether it supports FLR.
Co-developed-by: NAlex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20210817180500.1253-5-ameynarkhede03@gmail.comSigned-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NAmey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NAlex Williamson <alex.williamson@redhat.com>
Reviewed-by: NRaphael Norwitz <raphael.norwitz@nutanix.com>

Add reset_methods[] in struct pci_dev to keep track of reset mechanisms
supported by the device and their ordering.

Refactor probing and reset functions to take advantage of calling
convention of reset functions.
Co-developed-by: NAlex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20210817180500.1253-4-ameynarkhede03@gmail.comSigned-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NAmey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NRaphael Norwitz <raphael.norwitz@nutanix.com>

Most reset methods are of the form "pci_*_reset(dev, probe)".  pcie_flr()
was an exception because it relied on a separate pcie_has_flr() function
instead of taking a "probe" argument.

Add "pcie_reset_flr(dev, probe)" to follow the convention.  Remove
pcie_has_flr().

Some pcie_flr() callers that did not use pcie_has_flr() remain.

[bhelgaas: commit log, rework pcie_reset_flr() to use dev->devcap directly]
Link: https://lore.kernel.org/r/20210817180500.1253-3-ameynarkhede03@gmail.comSigned-off-by: NAmey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NRaphael Norwitz <raphael.norwitz@nutanix.com>

Add a new member called devcap in struct pci_dev for caching the PCIe
Device Capabilities register to avoid reading PCI_EXP_DEVCAP multiple
times.

Refactor pcie_has_flr() to use cached device capabilities.

Link: https://lore.kernel.org/r/20210817180500.1253-2-ameynarkhede03@gmail.comSigned-off-by: NAmey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NRaphael Norwitz <raphael.norwitz@nutanix.com>