kernel-fxtec-pro1x/drivers/acpi/pci_root.c
Matthew Garrett 3c076351c4 PCI: Rework ASPM disable code
Right now we forcibly clear ASPM state on all devices if the BIOS indicates
that the feature isn't supported. Based on the Microsoft presentation
"PCI Express In Depth for Windows Vista and Beyond", I'm starting to think
that this may be an error. The implication is that unless the platform
grants full control via _OSC, Windows will not touch any PCIe features -
including ASPM. In that case clearing ASPM state would be an error unless
the platform has granted us that control.

This patch reworks the ASPM disabling code such that the actual clearing
of state is triggered by a successful handoff of PCIe control to the OS.
The general ASPM code undergoes some changes in order to ensure that the
ability to clear the bits isn't overridden by ASPM having already been
disabled. Further, this theoretically now allows for situations where
only a subset of PCIe roots hand over control, leaving the others in the
BIOS state.

It's difficult to know for sure that this is the right thing to do -
there's zero public documentation on the interaction between all of these
components. But enough vendors enable ASPM on platforms and then set this
bit that it seems likely that they're expecting the OS to leave them alone.

Measured to save around 5W on an idle Thinkpad X220.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-12-05 10:21:45 -08:00

667 lines
17 KiB
C

/*
* pci_root.c - ACPI PCI Root Bridge Driver ($Revision: 40 $)
*
* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/pci.h>
#include <linux/pci-acpi.h>
#include <linux/pci-aspm.h>
#include <linux/acpi.h>
#include <linux/slab.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#include <acpi/apei.h>
#define PREFIX "ACPI: "
#define _COMPONENT ACPI_PCI_COMPONENT
ACPI_MODULE_NAME("pci_root");
#define ACPI_PCI_ROOT_CLASS "pci_bridge"
#define ACPI_PCI_ROOT_DEVICE_NAME "PCI Root Bridge"
static int acpi_pci_root_add(struct acpi_device *device);
static int acpi_pci_root_remove(struct acpi_device *device, int type);
static int acpi_pci_root_start(struct acpi_device *device);
#define ACPI_PCIE_REQ_SUPPORT (OSC_EXT_PCI_CONFIG_SUPPORT \
| OSC_ACTIVE_STATE_PWR_SUPPORT \
| OSC_CLOCK_PWR_CAPABILITY_SUPPORT \
| OSC_MSI_SUPPORT)
static const struct acpi_device_id root_device_ids[] = {
{"PNP0A03", 0},
{"", 0},
};
MODULE_DEVICE_TABLE(acpi, root_device_ids);
static struct acpi_driver acpi_pci_root_driver = {
.name = "pci_root",
.class = ACPI_PCI_ROOT_CLASS,
.ids = root_device_ids,
.ops = {
.add = acpi_pci_root_add,
.remove = acpi_pci_root_remove,
.start = acpi_pci_root_start,
},
};
static LIST_HEAD(acpi_pci_roots);
static struct acpi_pci_driver *sub_driver;
static DEFINE_MUTEX(osc_lock);
int acpi_pci_register_driver(struct acpi_pci_driver *driver)
{
int n = 0;
struct acpi_pci_root *root;
struct acpi_pci_driver **pptr = &sub_driver;
while (*pptr)
pptr = &(*pptr)->next;
*pptr = driver;
if (!driver->add)
return 0;
list_for_each_entry(root, &acpi_pci_roots, node) {
driver->add(root->device->handle);
n++;
}
return n;
}
EXPORT_SYMBOL(acpi_pci_register_driver);
void acpi_pci_unregister_driver(struct acpi_pci_driver *driver)
{
struct acpi_pci_root *root;
struct acpi_pci_driver **pptr = &sub_driver;
while (*pptr) {
if (*pptr == driver)
break;
pptr = &(*pptr)->next;
}
BUG_ON(!*pptr);
*pptr = (*pptr)->next;
if (!driver->remove)
return;
list_for_each_entry(root, &acpi_pci_roots, node)
driver->remove(root->device->handle);
}
EXPORT_SYMBOL(acpi_pci_unregister_driver);
acpi_handle acpi_get_pci_rootbridge_handle(unsigned int seg, unsigned int bus)
{
struct acpi_pci_root *root;
list_for_each_entry(root, &acpi_pci_roots, node)
if ((root->segment == (u16) seg) &&
(root->secondary.start == (u16) bus))
return root->device->handle;
return NULL;
}
EXPORT_SYMBOL_GPL(acpi_get_pci_rootbridge_handle);
/**
* acpi_is_root_bridge - determine whether an ACPI CA node is a PCI root bridge
* @handle - the ACPI CA node in question.
*
* Note: we could make this API take a struct acpi_device * instead, but
* for now, it's more convenient to operate on an acpi_handle.
*/
int acpi_is_root_bridge(acpi_handle handle)
{
int ret;
struct acpi_device *device;
ret = acpi_bus_get_device(handle, &device);
if (ret)
return 0;
ret = acpi_match_device_ids(device, root_device_ids);
if (ret)
return 0;
else
return 1;
}
EXPORT_SYMBOL_GPL(acpi_is_root_bridge);
static acpi_status
get_root_bridge_busnr_callback(struct acpi_resource *resource, void *data)
{
struct resource *res = data;
struct acpi_resource_address64 address;
if (resource->type != ACPI_RESOURCE_TYPE_ADDRESS16 &&
resource->type != ACPI_RESOURCE_TYPE_ADDRESS32 &&
resource->type != ACPI_RESOURCE_TYPE_ADDRESS64)
return AE_OK;
acpi_resource_to_address64(resource, &address);
if ((address.address_length > 0) &&
(address.resource_type == ACPI_BUS_NUMBER_RANGE)) {
res->start = address.minimum;
res->end = address.minimum + address.address_length - 1;
}
return AE_OK;
}
static acpi_status try_get_root_bridge_busnr(acpi_handle handle,
struct resource *res)
{
acpi_status status;
res->start = -1;
status =
acpi_walk_resources(handle, METHOD_NAME__CRS,
get_root_bridge_busnr_callback, res);
if (ACPI_FAILURE(status))
return status;
if (res->start == -1)
return AE_ERROR;
return AE_OK;
}
static void acpi_pci_bridge_scan(struct acpi_device *device)
{
int status;
struct acpi_device *child = NULL;
if (device->flags.bus_address)
if (device->parent && device->parent->ops.bind) {
status = device->parent->ops.bind(device);
if (!status) {
list_for_each_entry(child, &device->children, node)
acpi_pci_bridge_scan(child);
}
}
}
static u8 pci_osc_uuid_str[] = "33DB4D5B-1FF7-401C-9657-7441C03DD766";
static acpi_status acpi_pci_run_osc(acpi_handle handle,
const u32 *capbuf, u32 *retval)
{
struct acpi_osc_context context = {
.uuid_str = pci_osc_uuid_str,
.rev = 1,
.cap.length = 12,
.cap.pointer = (void *)capbuf,
};
acpi_status status;
status = acpi_run_osc(handle, &context);
if (ACPI_SUCCESS(status)) {
*retval = *((u32 *)(context.ret.pointer + 8));
kfree(context.ret.pointer);
}
return status;
}
static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root,
u32 support,
u32 *control)
{
acpi_status status;
u32 result, capbuf[3];
support &= OSC_PCI_SUPPORT_MASKS;
support |= root->osc_support_set;
capbuf[OSC_QUERY_TYPE] = OSC_QUERY_ENABLE;
capbuf[OSC_SUPPORT_TYPE] = support;
if (control) {
*control &= OSC_PCI_CONTROL_MASKS;
capbuf[OSC_CONTROL_TYPE] = *control | root->osc_control_set;
} else {
/* Run _OSC query for all possible controls. */
capbuf[OSC_CONTROL_TYPE] = OSC_PCI_CONTROL_MASKS;
}
status = acpi_pci_run_osc(root->device->handle, capbuf, &result);
if (ACPI_SUCCESS(status)) {
root->osc_support_set = support;
if (control)
*control = result;
}
return status;
}
static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)
{
acpi_status status;
acpi_handle tmp;
status = acpi_get_handle(root->device->handle, "_OSC", &tmp);
if (ACPI_FAILURE(status))
return status;
mutex_lock(&osc_lock);
status = acpi_pci_query_osc(root, flags, NULL);
mutex_unlock(&osc_lock);
return status;
}
struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
{
struct acpi_pci_root *root;
list_for_each_entry(root, &acpi_pci_roots, node) {
if (root->device->handle == handle)
return root;
}
return NULL;
}
EXPORT_SYMBOL_GPL(acpi_pci_find_root);
struct acpi_handle_node {
struct list_head node;
acpi_handle handle;
};
/**
* acpi_get_pci_dev - convert ACPI CA handle to struct pci_dev
* @handle: the handle in question
*
* Given an ACPI CA handle, the desired PCI device is located in the
* list of PCI devices.
*
* If the device is found, its reference count is increased and this
* function returns a pointer to its data structure. The caller must
* decrement the reference count by calling pci_dev_put().
* If no device is found, %NULL is returned.
*/
struct pci_dev *acpi_get_pci_dev(acpi_handle handle)
{
int dev, fn;
unsigned long long adr;
acpi_status status;
acpi_handle phandle;
struct pci_bus *pbus;
struct pci_dev *pdev = NULL;
struct acpi_handle_node *node, *tmp;
struct acpi_pci_root *root;
LIST_HEAD(device_list);
/*
* Walk up the ACPI CA namespace until we reach a PCI root bridge.
*/
phandle = handle;
while (!acpi_is_root_bridge(phandle)) {
node = kzalloc(sizeof(struct acpi_handle_node), GFP_KERNEL);
if (!node)
goto out;
INIT_LIST_HEAD(&node->node);
node->handle = phandle;
list_add(&node->node, &device_list);
status = acpi_get_parent(phandle, &phandle);
if (ACPI_FAILURE(status))
goto out;
}
root = acpi_pci_find_root(phandle);
if (!root)
goto out;
pbus = root->bus;
/*
* Now, walk back down the PCI device tree until we return to our
* original handle. Assumes that everything between the PCI root
* bridge and the device we're looking for must be a P2P bridge.
*/
list_for_each_entry(node, &device_list, node) {
acpi_handle hnd = node->handle;
status = acpi_evaluate_integer(hnd, "_ADR", NULL, &adr);
if (ACPI_FAILURE(status))
goto out;
dev = (adr >> 16) & 0xffff;
fn = adr & 0xffff;
pdev = pci_get_slot(pbus, PCI_DEVFN(dev, fn));
if (!pdev || hnd == handle)
break;
pbus = pdev->subordinate;
pci_dev_put(pdev);
/*
* This function may be called for a non-PCI device that has a
* PCI parent (eg. a disk under a PCI SATA controller). In that
* case pdev->subordinate will be NULL for the parent.
*/
if (!pbus) {
dev_dbg(&pdev->dev, "Not a PCI-to-PCI bridge\n");
pdev = NULL;
break;
}
}
out:
list_for_each_entry_safe(node, tmp, &device_list, node)
kfree(node);
return pdev;
}
EXPORT_SYMBOL_GPL(acpi_get_pci_dev);
/**
* acpi_pci_osc_control_set - Request control of PCI root _OSC features.
* @handle: ACPI handle of a PCI root bridge (or PCIe Root Complex).
* @mask: Mask of _OSC bits to request control of, place to store control mask.
* @req: Mask of _OSC bits the control of is essential to the caller.
*
* Run _OSC query for @mask and if that is successful, compare the returned
* mask of control bits with @req. If all of the @req bits are set in the
* returned mask, run _OSC request for it.
*
* The variable at the @mask address may be modified regardless of whether or
* not the function returns success. On success it will contain the mask of
* _OSC bits the BIOS has granted control of, but its contents are meaningless
* on failure.
**/
acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req)
{
struct acpi_pci_root *root;
acpi_status status;
u32 ctrl, capbuf[3];
acpi_handle tmp;
if (!mask)
return AE_BAD_PARAMETER;
ctrl = *mask & OSC_PCI_CONTROL_MASKS;
if ((ctrl & req) != req)
return AE_TYPE;
root = acpi_pci_find_root(handle);
if (!root)
return AE_NOT_EXIST;
status = acpi_get_handle(handle, "_OSC", &tmp);
if (ACPI_FAILURE(status))
return status;
mutex_lock(&osc_lock);
*mask = ctrl | root->osc_control_set;
/* No need to evaluate _OSC if the control was already granted. */
if ((root->osc_control_set & ctrl) == ctrl)
goto out;
/* Need to check the available controls bits before requesting them. */
while (*mask) {
status = acpi_pci_query_osc(root, root->osc_support_set, mask);
if (ACPI_FAILURE(status))
goto out;
if (ctrl == *mask)
break;
ctrl = *mask;
}
if ((ctrl & req) != req) {
status = AE_SUPPORT;
goto out;
}
capbuf[OSC_QUERY_TYPE] = 0;
capbuf[OSC_SUPPORT_TYPE] = root->osc_support_set;
capbuf[OSC_CONTROL_TYPE] = ctrl;
status = acpi_pci_run_osc(handle, capbuf, mask);
if (ACPI_SUCCESS(status))
root->osc_control_set = *mask;
out:
mutex_unlock(&osc_lock);
return status;
}
EXPORT_SYMBOL(acpi_pci_osc_control_set);
static int __devinit acpi_pci_root_add(struct acpi_device *device)
{
unsigned long long segment, bus;
acpi_status status;
int result;
struct acpi_pci_root *root;
acpi_handle handle;
struct acpi_device *child;
u32 flags, base_flags;
root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
if (!root)
return -ENOMEM;
segment = 0;
status = acpi_evaluate_integer(device->handle, METHOD_NAME__SEG, NULL,
&segment);
if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
printk(KERN_ERR PREFIX "can't evaluate _SEG\n");
result = -ENODEV;
goto end;
}
/* Check _CRS first, then _BBN. If no _BBN, default to zero. */
root->secondary.flags = IORESOURCE_BUS;
status = try_get_root_bridge_busnr(device->handle, &root->secondary);
if (ACPI_FAILURE(status)) {
/*
* We need both the start and end of the downstream bus range
* to interpret _CBA (MMCONFIG base address), so it really is
* supposed to be in _CRS. If we don't find it there, all we
* can do is assume [_BBN-0xFF] or [0-0xFF].
*/
root->secondary.end = 0xFF;
printk(KERN_WARNING FW_BUG PREFIX
"no secondary bus range in _CRS\n");
status = acpi_evaluate_integer(device->handle, METHOD_NAME__BBN,
NULL, &bus);
if (ACPI_SUCCESS(status))
root->secondary.start = bus;
else if (status == AE_NOT_FOUND)
root->secondary.start = 0;
else {
printk(KERN_ERR PREFIX "can't evaluate _BBN\n");
result = -ENODEV;
goto end;
}
}
INIT_LIST_HEAD(&root->node);
root->device = device;
root->segment = segment & 0xFFFF;
strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
device->driver_data = root;
/*
* All supported architectures that use ACPI have support for
* PCI domains, so we indicate this in _OSC support capabilities.
*/
flags = base_flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
acpi_pci_osc_support(root, flags);
/*
* TBD: Need PCI interface for enumeration/configuration of roots.
*/
/* TBD: Locking */
list_add_tail(&root->node, &acpi_pci_roots);
printk(KERN_INFO PREFIX "%s [%s] (domain %04x %pR)\n",
acpi_device_name(device), acpi_device_bid(device),
root->segment, &root->secondary);
/*
* Scan the Root Bridge
* --------------------
* Must do this prior to any attempt to bind the root device, as the
* PCI namespace does not get created until this call is made (and
* thus the root bridge's pci_dev does not exist).
*/
root->bus = pci_acpi_scan_root(root);
if (!root->bus) {
printk(KERN_ERR PREFIX
"Bus %04x:%02x not present in PCI namespace\n",
root->segment, (unsigned int)root->secondary.start);
result = -ENODEV;
goto end;
}
/*
* Attach ACPI-PCI Context
* -----------------------
* Thus binding the ACPI and PCI devices.
*/
result = acpi_pci_bind_root(device);
if (result)
goto end;
/*
* PCI Routing Table
* -----------------
* Evaluate and parse _PRT, if exists.
*/
status = acpi_get_handle(device->handle, METHOD_NAME__PRT, &handle);
if (ACPI_SUCCESS(status))
result = acpi_pci_irq_add_prt(device->handle, root->bus);
/*
* Scan and bind all _ADR-Based Devices
*/
list_for_each_entry(child, &device->children, node)
acpi_pci_bridge_scan(child);
/* Indicate support for various _OSC capabilities. */
if (pci_ext_cfg_avail(root->bus->self))
flags |= OSC_EXT_PCI_CONFIG_SUPPORT;
if (pcie_aspm_support_enabled())
flags |= OSC_ACTIVE_STATE_PWR_SUPPORT |
OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
if (pci_msi_enabled())
flags |= OSC_MSI_SUPPORT;
if (flags != base_flags)
acpi_pci_osc_support(root, flags);
if (!pcie_ports_disabled
&& (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) {
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(root->bus->bridge,
"PCIe errors handled by BIOS.\n");
else
flags |= OSC_PCI_EXPRESS_AER_CONTROL;
}
dev_info(root->bus->bridge,
"Requesting ACPI _OSC control (0x%02x)\n", flags);
status = acpi_pci_osc_control_set(device->handle, &flags,
OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL);
if (ACPI_SUCCESS(status)) {
dev_info(root->bus->bridge,
"ACPI _OSC control (0x%02x) granted\n", flags);
if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
/*
* We have ASPM control, but the FADT indicates
* that it's unsupported. Clear it.
*/
pcie_clear_aspm(root->bus);
}
} else {
dev_info(root->bus->bridge,
"ACPI _OSC request failed (%s), "
"returned control mask: 0x%02x\n",
acpi_format_exception(status), flags);
pr_info("ACPI _OSC control for PCIe not granted, "
"disabling ASPM\n");
pcie_no_aspm();
}
} else {
dev_info(root->bus->bridge,
"Unable to request _OSC control "
"(_OSC support mask: 0x%02x)\n", flags);
}
pci_acpi_add_bus_pm_notifier(device, root->bus);
if (device->wakeup.flags.run_wake)
device_set_run_wake(root->bus->bridge, true);
return 0;
end:
if (!list_empty(&root->node))
list_del(&root->node);
kfree(root);
return result;
}
static int acpi_pci_root_start(struct acpi_device *device)
{
struct acpi_pci_root *root = acpi_driver_data(device);
pci_bus_add_devices(root->bus);
return 0;
}
static int acpi_pci_root_remove(struct acpi_device *device, int type)
{
struct acpi_pci_root *root = acpi_driver_data(device);
device_set_run_wake(root->bus->bridge, false);
pci_acpi_remove_bus_pm_notifier(device);
kfree(root);
return 0;
}
static int __init acpi_pci_root_init(void)
{
acpi_hest_init();
if (acpi_pci_disabled)
return 0;
pci_acpi_crs_quirks();
if (acpi_bus_register_driver(&acpi_pci_root_driver) < 0)
return -ENODEV;
return 0;
}
subsys_initcall(acpi_pci_root_init);