android_kernel_xiaomi_sm8350/drivers/pci/pcie/portdrv_acpi.c
Rafael J. Wysocki b22c3d8275 PCI/PCIe/AER: Disable native AER service if BIOS has precedence
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: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2010-10-15 13:09:50 -07:00

78 lines
2.2 KiB
C

/*
* PCIe Port Native Services Support, ACPI-Related Part
*
* Copyright (C) 2010 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
*
* This file is subject to the terms and conditions of the GNU General Public
* License V2. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/acpi.h>
#include <linux/pci-acpi.h>
#include <linux/pcieport_if.h>
#include "aer/aerdrv.h"
#include "../pci.h"
/**
* pcie_port_acpi_setup - Request the BIOS to release control of PCIe services.
* @port: PCIe Port service for a root port or event collector.
* @srv_mask: Bit mask of services that can be enabled for @port.
*
* Invoked when @port is identified as a PCIe port device. To avoid conflicts
* with the BIOS PCIe port native services support requires the BIOS to yield
* control of these services to the kernel. The mask of services that the BIOS
* allows to be enabled for @port is written to @srv_mask.
*
* NOTE: It turns out that we cannot do that for individual port services
* separately, because that would make some systems work incorrectly.
*/
int pcie_port_acpi_setup(struct pci_dev *port, int *srv_mask)
{
acpi_status status;
acpi_handle handle;
u32 flags;
if (acpi_pci_disabled)
return 0;
handle = acpi_find_root_bridge_handle(port);
if (!handle)
return -EINVAL;
flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL
| OSC_PCI_EXPRESS_NATIVE_HP_CONTROL
| OSC_PCI_EXPRESS_PME_CONTROL;
if (pci_aer_available()) {
if (aer_acpi_firmware_first())
dev_dbg(&port->dev, "PCIe errors handled by BIOS.\n");
else
flags |= OSC_PCI_EXPRESS_AER_CONTROL;
}
status = acpi_pci_osc_control_set(handle, &flags,
OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL);
if (ACPI_FAILURE(status)) {
dev_dbg(&port->dev, "ACPI _OSC request failed (code %d)\n",
status);
return -ENODEV;
}
dev_info(&port->dev, "ACPI _OSC control granted for 0x%02x\n", flags);
*srv_mask = PCIE_PORT_SERVICE_VC;
if (flags & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL)
*srv_mask |= PCIE_PORT_SERVICE_HP;
if (flags & OSC_PCI_EXPRESS_PME_CONTROL)
*srv_mask |= PCIE_PORT_SERVICE_PME;
if (flags & OSC_PCI_EXPRESS_AER_CONTROL)
*srv_mask |= PCIE_PORT_SERVICE_AER;
return 0;
}