linux/drivers/pci/pci-acpi.c
Rafael J. Wysocki 0baed8da1e PCI / ACPI PM: Propagate wake-up enable for devices w/o ACPI support
Some PCI devices (not PCI Express), like PCI add-on cards, can
generate PME#, but they don't have any special platform wake-up
support.  For this reason, even if they generate PME# to wake up the
system from a sleep state, wake-up events are not generated by the
platform.

It turns out that, at least on some systems, PCI bridges and the PCI
host bridge have ACPI GPEs associated with them that, if enabled to
generate wake-up events, allow the system to wake up if one of the
add-on devices asserts PME# while the system is in a sleep state.
Following this observation, if a PCI device without direct ACPI
wake-up support is prepared to wake up the system during a transition
into a sleep state (eg. suspend to RAM), try to configure the bridges
on the path from the device to the root bridge to wake-up the system.

Reviewed-by: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-09 14:19:24 -07:00

208 lines
5.0 KiB
C

/*
* File: pci-acpi.c
* Purpose: Provide PCI support in ACPI
*
* Copyright (C) 2005 David Shaohua Li <shaohua.li@intel.com>
* Copyright (C) 2004 Tom Long Nguyen <tom.l.nguyen@intel.com>
* Copyright (C) 2004 Intel Corp.
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/module.h>
#include <linux/pci-aspm.h>
#include <acpi/acpi.h>
#include <acpi/acpi_bus.h>
#include <linux/pci-acpi.h>
#include "pci.h"
/*
* _SxD returns the D-state with the highest power
* (lowest D-state number) supported in the S-state "x".
*
* If the devices does not have a _PRW
* (Power Resources for Wake) supporting system wakeup from "x"
* then the OS is free to choose a lower power (higher number
* D-state) than the return value from _SxD.
*
* But if _PRW is enabled at S-state "x", the OS
* must not choose a power lower than _SxD --
* unless the device has an _SxW method specifying
* the lowest power (highest D-state number) the device
* may enter while still able to wake the system.
*
* ie. depending on global OS policy:
*
* if (_PRW at S-state x)
* choose from highest power _SxD to lowest power _SxW
* else // no _PRW at S-state x
* choose highest power _SxD or any lower power
*/
static pci_power_t acpi_pci_choose_state(struct pci_dev *pdev)
{
int acpi_state;
acpi_state = acpi_pm_device_sleep_state(&pdev->dev, NULL);
if (acpi_state < 0)
return PCI_POWER_ERROR;
switch (acpi_state) {
case ACPI_STATE_D0:
return PCI_D0;
case ACPI_STATE_D1:
return PCI_D1;
case ACPI_STATE_D2:
return PCI_D2;
case ACPI_STATE_D3:
return PCI_D3hot;
}
return PCI_POWER_ERROR;
}
static bool acpi_pci_power_manageable(struct pci_dev *dev)
{
acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
return handle ? acpi_bus_power_manageable(handle) : false;
}
static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
{
acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
acpi_handle tmp;
static const u8 state_conv[] = {
[PCI_D0] = ACPI_STATE_D0,
[PCI_D1] = ACPI_STATE_D1,
[PCI_D2] = ACPI_STATE_D2,
[PCI_D3hot] = ACPI_STATE_D3,
[PCI_D3cold] = ACPI_STATE_D3
};
int error = -EINVAL;
/* If the ACPI device has _EJ0, ignore the device */
if (!handle || ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0", &tmp)))
return -ENODEV;
switch (state) {
case PCI_D0:
case PCI_D1:
case PCI_D2:
case PCI_D3hot:
case PCI_D3cold:
error = acpi_bus_set_power(handle, state_conv[state]);
}
if (!error)
dev_printk(KERN_INFO, &dev->dev,
"power state changed by ACPI to D%d\n", state);
return error;
}
static bool acpi_pci_can_wakeup(struct pci_dev *dev)
{
acpi_handle handle = DEVICE_ACPI_HANDLE(&dev->dev);
return handle ? acpi_bus_can_wakeup(handle) : false;
}
static void acpi_pci_propagate_wakeup_enable(struct pci_bus *bus, bool enable)
{
while (bus->parent) {
struct pci_dev *bridge = bus->self;
int ret;
ret = acpi_pm_device_sleep_wake(&bridge->dev, enable);
if (!ret || bridge->is_pcie)
return;
bus = bus->parent;
}
/* We have reached the root bus. */
if (bus->bridge)
acpi_pm_device_sleep_wake(bus->bridge, enable);
}
static int acpi_pci_sleep_wake(struct pci_dev *dev, bool enable)
{
if (acpi_pci_can_wakeup(dev))
return acpi_pm_device_sleep_wake(&dev->dev, enable);
if (!dev->is_pcie)
acpi_pci_propagate_wakeup_enable(dev->bus, enable);
return 0;
}
static struct pci_platform_pm_ops acpi_pci_platform_pm = {
.is_manageable = acpi_pci_power_manageable,
.set_state = acpi_pci_set_power_state,
.choose_state = acpi_pci_choose_state,
.can_wakeup = acpi_pci_can_wakeup,
.sleep_wake = acpi_pci_sleep_wake,
};
/* ACPI bus type */
static int acpi_pci_find_device(struct device *dev, acpi_handle *handle)
{
struct pci_dev * pci_dev;
acpi_integer addr;
pci_dev = to_pci_dev(dev);
/* Please ref to ACPI spec for the syntax of _ADR */
addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn);
*handle = acpi_get_child(DEVICE_ACPI_HANDLE(dev->parent), addr);
if (!*handle)
return -ENODEV;
return 0;
}
static int acpi_pci_find_root_bridge(struct device *dev, acpi_handle *handle)
{
int num;
unsigned int seg, bus;
/*
* The string should be the same as root bridge's name
* Please look at 'pci_scan_bus_parented'
*/
num = sscanf(dev_name(dev), "pci%04x:%02x", &seg, &bus);
if (num != 2)
return -ENODEV;
*handle = acpi_get_pci_rootbridge_handle(seg, bus);
if (!*handle)
return -ENODEV;
return 0;
}
static struct acpi_bus_type acpi_pci_bus = {
.bus = &pci_bus_type,
.find_device = acpi_pci_find_device,
.find_bridge = acpi_pci_find_root_bridge,
};
static int __init acpi_pci_init(void)
{
int ret;
if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_MSI) {
printk(KERN_INFO"ACPI FADT declares the system doesn't support MSI, so disable it\n");
pci_no_msi();
}
if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
printk(KERN_INFO"ACPI FADT declares the system doesn't support PCIe ASPM, so disable it\n");
pcie_no_aspm();
}
ret = register_acpi_bus_type(&acpi_pci_bus);
if (ret)
return 0;
pci_set_platform_pm(&acpi_pci_platform_pm);
return 0;
}
arch_initcall(acpi_pci_init);