PCI/VC: Use FIELD_GET()

Use FIELD_GET() to remove dependences on the field position, i.e., the
shift value. No functional change intended.

Link: https://lore.kernel.org/r/20231010204436.1000644-10-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

PCI: Fix kerneldoc warnings

Fix kerneldoc warnings, e.g.,

$ make W=1 drivers/pci/
drivers/pci/ats.c:196: warning: Function parameter or member 'pdev' not described in 'pci_enable_pri'
drivers/pci/ats.c:196: warning: Function parameter or member 'reqs' not described in 'pci_enable_pri'
...

Link: https://lore.kernel.org/r/20200729201224.26799-2-krzk@kernel.org
Link: https://lore.kernel.org/r/20200729201224.26799-3-krzk@kernel.org
Link: https://lore.kernel.org/r/20200729201224.26799-4-krzk@kernel.org
Link: https://lore.kernel.org/r/20200729201224.26799-5-krzk@kernel.org
Link: https://lore.kernel.org/r/20200729201224.26799-6-krzk@kernel.org
Link: https://lore.kernel.org/r/20200729201224.26799-7-krzk@kernel.org
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI: Get rid of dev->has_secondary_link flag

In some systems, the Device/Port Type in the PCI Express Capabilities
register incorrectly identifies upstream ports as downstream ports.

d0751b98dfa3 ("PCI: Add dev->has_secondary_link to track downstream PCIe
links") addressed this by adding pci_dev.has_secondary_link, which is set
for downstream ports. But this is confusing because pci_pcie_type()
sometimes gives the wrong answer, and it's not obvious that we should use
pci_dev.has_secondary_link instead.

Reduce the confusion by correcting the type of the port itself so that
pci_pcie_type() returns the actual type regardless of what the Device/Port
Type register claims it is. Update the users to call pci_pcie_type() and
pcie_downstream_port() accordingly, and remove pci_dev.has_secondary_link
completely.

Link: https://lore.kernel.org/linux-pci/20190703133953.GK128603@google.com/
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20190822085553.62697-2-mika.westerberg@linux.intel.com
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

PCI: Fix typos and whitespace errors

Fix typos in drivers/pci. Comment and whitespace changes only.

Link: https://lore.kernel.org/r/20190819115306.27338-1-kw@linux.com
Signed-off-by: Krzysztof Wilczynski <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> # armada8k

PCI: Add SPDX GPL-2.0 to replace GPL v2 boilerplate

Add SPDX GPL-2.0 to all PCI files that specified the GPL version 2 license.

Remove the boilerplate GPL version 2 language, relying on the assertion in
b24413180f56 ("License cleanup: add SPDX GPL-2.0 license identifier to
files with no license") that the SPDX identifier may be used instead of the
full boilerplate text.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PCI: Add wrappers for dev_printk()

Add PCI-specific dev_printk() wrappers and use them to simplify the code
slightly. No functional change intended.

Signed-off-by: Frederick Lawler <fred@fredlawl.com>
[bhelgaas: squash into one patch]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI: Fix unaligned accesses in VC code

The save/restore buffers for VC state is first composed of a 2-byte control
register, then a bunch of 4-byte words.

This causes unaligned accesses which trap on platform such as sparc.

This is easy to fix by simply moving the buffer pointer forward by 4 bytes
instead of 2 after dealing with the control register. The length
adjustment needs to be changed likewise as well.

Fixes: 5f8fc43217a0 ("PCI: Include pci/pcie/Kconfig directly from pci/Kconfig")
Reported-by: Meelis Roos <mroos@linux.ee>
Reported-by: Anatoly Pugachev <matorola@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org # v4.6+

PCI: Use dev->has_secondary_link to find downstream PCIe links

Previously we assumed that PCIe Root Ports and Downstream Ports had Links
on their secondary side. That is true in most systems, but it is possible
to connect a switch with either an Upstream or a Downstream Port leading
downstream.

Instead of relying on the component type to identify devices that have
links leading downstream, use the "dev->has_secondary_link" field.

[bhelgaas: changelog]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI: Rename PCI_VC_PORT_REG1/2 to PCI_VC_PORT_CAP1/2

These are set of two capability registers, it's pretty much given that
they're registers, so reflect their purpose in the name.

Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI: Add Virtual Channel to save/restore support

While we don't really have any infrastructure for making use of VC
support, the system BIOS can configure the topology to non-default
VC values prior to boot. This may be due to silicon bugs, desire to
reserve traffic classes, or perhaps just BIOS bugs. When we reset
devices, the VC configuration may return to default values, which can
be incompatible with devices upstream. For instance, Nvidia GRID
cards provide a PCIe switch and some number of GPUs, all supporting
VC. The power-on default for VC is to support TC0-7 across VC0,
however some platforms will only enable TC0/VC0 mapping across the
topology. When we do a secondary bus reset on the downstream switch
port, the GPU is reset to a TC0-7/VC0 mapping while the opposite end
of the link only enables TC0/VC0. If the GPU attempts to use TC1-7,
it fails.

This patch attempts to provide complete support for VC save/restore,
even beyond the minimally required use case above. This includes
save/restore and reload of the arbitration table, save/restore and
reload of the port arbitration tables, and re-enabling of the
channels for VC, VC9, and MFVC capabilities.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>