This fixes a "no previous prototype" warning for pcie_port_acpi_setup()
found via "make W=1".

[bhelgaas: changelog]
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Move the evaluation of acpi_pci_osc_control_set() (to request control of
PCI Express native features) into acpi_pci_root_add() to avoid calling
it many times for the same root complex with the same arguments.
Additionally, check if all of the requisite _OSC support bits are set
before calling acpi_pci_osc_control_set() for a given root complex.

References: https://bugzilla.kernel.org/show_bug.cgi?id=20232Reported-by: NOzan Caglayan <ozan@pardus.org.tr>
Tested-by: NOzan Caglayan <ozan@pardus.org.tr>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

There is a design issue related to PCIe AER and _OSC that the BIOS
may be asked to grant control of the AER service even if some
Hardware Error Source Table (HEST) entries contain information
meaning that the BIOS really should control it.  Namely,
pcie_port_acpi_setup() calls pcie_aer_get_firmware_first() that
determines whether or not the AER service should be controlled by
the BIOS on the basis of the HEST information for the given PCIe
port.  The BIOS is asked to grant control of the AER service for
a PCIe Root Complex if pcie_aer_get_firmware_first() returns 'false'
for at least one root port in that complex, even if all of the other
root ports' HEST entries have the FIRMWARE_FIRST flag set (and none
of them has the GLOBAL flag set).  However, if the AER service is
controlled by the kernel, that may interfere with the BIOS' handling
of the error sources having the FIRMWARE_FIRST flag.  Moreover,
there may be PCIe endpoints that have the FIRMWARE_FIRST flag set in
HEST and are attached to the root ports in question, in which case it
also may be unsafe to ask the BIOS for control of the AER service.

For this reason, introduce a function checking if there's at least
one PCIe-related HEST entry with the FIRMWARE_FIRST flag set and
disable the native AER service altogether if this function returns
'true'.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

After commit 852972ac (ACPI: Disable
ASPM if the platform won't provide _OSC control for PCIe) control of
the PCIe Capability Structure is unconditionally requested by
acpi_pci_root_add(), which in principle may cause problems to
happen in two ways.  First, the BIOS may refuse to give control of
the PCIe Capability Structure if it is not asked for any of the
_OSC features depending on it at the same time.  Second, the BIOS may
assume that control of the _OSC features depending on the PCIe
Capability Structure will be requested in the future and may behave
incorrectly if that doesn't happen.  For this reason, control of
the PCIe Capability Structure should always be requested along with
control of any other _OSC features that may depend on it (ie. PCIe
native PME, PCIe native hot-plug, PCIe AER).

Rework the PCIe port driver so that (1) it checks which native PCIe
port services can be enabled, according to the BIOS, and (2) it
requests control of all these services simultaneously.  In
particular, this causes pcie_portdrv_probe() to fail if the BIOS
refuses to grant control of the PCIe Capability Structure, which
means that no native PCIe port services can be enabled for the PCIe
Root Complex the given port belongs to.  If that happens, ASPM is
disabled to avoid problems with mishandling it by the part of the
PCIe hierarchy for which control of the PCIe Capability Structure
has not been received.

Make it possible to override this behavior using 'pcie_ports=native'
(use the PCIe native services regardless of the BIOS response to the
control request), or 'pcie_ports=compat' (do not use the PCIe native
services at all).

Accordingly, rework the existing PCIe port service drivers so that
they don't request control of the services directly.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>