linux/drivers/pci/pcie/aspm.c
Naga Chumbalkar bbfa306a1e PCI: Changing ASPM policy, via /sys, to POWERSAVE could cause NMIs
v3 -> v2: Modified the text that describes the problem
v2 -> v1: Returned -EPERM
v1      : http://marc.info/?l=linux-pci&m=130013194803727&w=2

For servers whose hardware cannot handle ASPM the BIOS ought to set the
FADT bit shown below:
In Sec 5.2.9.3 (IA-PC Boot Arch. Flags) of ACPI4.0a Specification, please
see Table 5-11:
PCIe ASPM Controls: If set, indicates to OSPM that it must not enable
OPSM ASPM control on this platform.

However there are shipping servers whose BIOS did not set this bit. (An
example is the HP ProLiant DL385 G6. A Maintenance BIOS will fix that).
For such servers even if a call is made via pci_no_aspm(), based on _OSC
support in the BIOS, it may be too late because the ASPM code may have
already allocated and filled its "link_list".

So if a user sets the ASPM "policy" to "powersave" via /sys then
pcie_aspm_set_policy() will run through the "link_list" and re-configure
ASPM policy on devices that advertise ASPM L0s/L1 capability:
# echo powersave > /sys/module/pcie_aspm/parameters/policy
# cat /sys/module/pcie_aspm/parameters/policy
default performance [powersave]

That can cause NMIs since the hardware doesn't play well with ASPM:
[ 1651.906015] NMI: PCI system error (SERR) for reason b1 on CPU 0.
[ 1651.906015] Dazed and confused, but trying to continue

Ideally, the BIOS should have set that FADT bit in the first place but we
could be more robust - especially given the fact that Windows doesn't
cause NMIs in the above scenario.

There should be a sanity check to not allow a user to modify ASPM policy
when aspm_disabled is set.

Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-03-21 09:40:57 -07:00

966 lines
26 KiB
C

/*
* File: drivers/pci/pcie/aspm.c
* Enabling PCIe link L0s/L1 state and Clock Power Management
*
* Copyright (C) 2007 Intel
* Copyright (C) Zhang Yanmin (yanmin.zhang@intel.com)
* Copyright (C) Shaohua Li (shaohua.li@intel.com)
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/pci.h>
#include <linux/pci_regs.h>
#include <linux/errno.h>
#include <linux/pm.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/delay.h>
#include <linux/pci-aspm.h>
#include "../pci.h"
#ifdef MODULE_PARAM_PREFIX
#undef MODULE_PARAM_PREFIX
#endif
#define MODULE_PARAM_PREFIX "pcie_aspm."
/* Note: those are not register definitions */
#define ASPM_STATE_L0S_UP (1) /* Upstream direction L0s state */
#define ASPM_STATE_L0S_DW (2) /* Downstream direction L0s state */
#define ASPM_STATE_L1 (4) /* L1 state */
#define ASPM_STATE_L0S (ASPM_STATE_L0S_UP | ASPM_STATE_L0S_DW)
#define ASPM_STATE_ALL (ASPM_STATE_L0S | ASPM_STATE_L1)
struct aspm_latency {
u32 l0s; /* L0s latency (nsec) */
u32 l1; /* L1 latency (nsec) */
};
struct pcie_link_state {
struct pci_dev *pdev; /* Upstream component of the Link */
struct pcie_link_state *root; /* pointer to the root port link */
struct pcie_link_state *parent; /* pointer to the parent Link state */
struct list_head sibling; /* node in link_list */
struct list_head children; /* list of child link states */
struct list_head link; /* node in parent's children list */
/* ASPM state */
u32 aspm_support:3; /* Supported ASPM state */
u32 aspm_enabled:3; /* Enabled ASPM state */
u32 aspm_capable:3; /* Capable ASPM state with latency */
u32 aspm_default:3; /* Default ASPM state by BIOS */
u32 aspm_disable:3; /* Disabled ASPM state */
/* Clock PM state */
u32 clkpm_capable:1; /* Clock PM capable? */
u32 clkpm_enabled:1; /* Current Clock PM state */
u32 clkpm_default:1; /* Default Clock PM state by BIOS */
/* Exit latencies */
struct aspm_latency latency_up; /* Upstream direction exit latency */
struct aspm_latency latency_dw; /* Downstream direction exit latency */
/*
* Endpoint acceptable latencies. A pcie downstream port only
* has one slot under it, so at most there are 8 functions.
*/
struct aspm_latency acceptable[8];
};
static int aspm_disabled, aspm_force, aspm_clear_state;
static bool aspm_support_enabled = true;
static DEFINE_MUTEX(aspm_lock);
static LIST_HEAD(link_list);
#define POLICY_DEFAULT 0 /* BIOS default setting */
#define POLICY_PERFORMANCE 1 /* high performance */
#define POLICY_POWERSAVE 2 /* high power saving */
static int aspm_policy;
static const char *policy_str[] = {
[POLICY_DEFAULT] = "default",
[POLICY_PERFORMANCE] = "performance",
[POLICY_POWERSAVE] = "powersave"
};
#define LINK_RETRAIN_TIMEOUT HZ
static int policy_to_aspm_state(struct pcie_link_state *link)
{
switch (aspm_policy) {
case POLICY_PERFORMANCE:
/* Disable ASPM and Clock PM */
return 0;
case POLICY_POWERSAVE:
/* Enable ASPM L0s/L1 */
return ASPM_STATE_ALL;
case POLICY_DEFAULT:
return link->aspm_default;
}
return 0;
}
static int policy_to_clkpm_state(struct pcie_link_state *link)
{
switch (aspm_policy) {
case POLICY_PERFORMANCE:
/* Disable ASPM and Clock PM */
return 0;
case POLICY_POWERSAVE:
/* Disable Clock PM */
return 1;
case POLICY_DEFAULT:
return link->clkpm_default;
}
return 0;
}
static void pcie_set_clkpm_nocheck(struct pcie_link_state *link, int enable)
{
int pos;
u16 reg16;
struct pci_dev *child;
struct pci_bus *linkbus = link->pdev->subordinate;
list_for_each_entry(child, &linkbus->devices, bus_list) {
pos = pci_pcie_cap(child);
if (!pos)
return;
pci_read_config_word(child, pos + PCI_EXP_LNKCTL, &reg16);
if (enable)
reg16 |= PCI_EXP_LNKCTL_CLKREQ_EN;
else
reg16 &= ~PCI_EXP_LNKCTL_CLKREQ_EN;
pci_write_config_word(child, pos + PCI_EXP_LNKCTL, reg16);
}
link->clkpm_enabled = !!enable;
}
static void pcie_set_clkpm(struct pcie_link_state *link, int enable)
{
/* Don't enable Clock PM if the link is not Clock PM capable */
if (!link->clkpm_capable && enable)
enable = 0;
/* Need nothing if the specified equals to current state */
if (link->clkpm_enabled == enable)
return;
pcie_set_clkpm_nocheck(link, enable);
}
static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
{
int pos, capable = 1, enabled = 1;
u32 reg32;
u16 reg16;
struct pci_dev *child;
struct pci_bus *linkbus = link->pdev->subordinate;
/* All functions should have the same cap and state, take the worst */
list_for_each_entry(child, &linkbus->devices, bus_list) {
pos = pci_pcie_cap(child);
if (!pos)
return;
pci_read_config_dword(child, pos + PCI_EXP_LNKCAP, &reg32);
if (!(reg32 & PCI_EXP_LNKCAP_CLKPM)) {
capable = 0;
enabled = 0;
break;
}
pci_read_config_word(child, pos + PCI_EXP_LNKCTL, &reg16);
if (!(reg16 & PCI_EXP_LNKCTL_CLKREQ_EN))
enabled = 0;
}
link->clkpm_enabled = enabled;
link->clkpm_default = enabled;
link->clkpm_capable = (blacklist) ? 0 : capable;
}
/*
* pcie_aspm_configure_common_clock: check if the 2 ends of a link
* could use common clock. If they are, configure them to use the
* common clock. That will reduce the ASPM state exit latency.
*/
static void pcie_aspm_configure_common_clock(struct pcie_link_state *link)
{
int ppos, cpos, same_clock = 1;
u16 reg16, parent_reg, child_reg[8];
unsigned long start_jiffies;
struct pci_dev *child, *parent = link->pdev;
struct pci_bus *linkbus = parent->subordinate;
/*
* All functions of a slot should have the same Slot Clock
* Configuration, so just check one function
*/
child = list_entry(linkbus->devices.next, struct pci_dev, bus_list);
BUG_ON(!pci_is_pcie(child));
/* Check downstream component if bit Slot Clock Configuration is 1 */
cpos = pci_pcie_cap(child);
pci_read_config_word(child, cpos + PCI_EXP_LNKSTA, &reg16);
if (!(reg16 & PCI_EXP_LNKSTA_SLC))
same_clock = 0;
/* Check upstream component if bit Slot Clock Configuration is 1 */
ppos = pci_pcie_cap(parent);
pci_read_config_word(parent, ppos + PCI_EXP_LNKSTA, &reg16);
if (!(reg16 & PCI_EXP_LNKSTA_SLC))
same_clock = 0;
/* Configure downstream component, all functions */
list_for_each_entry(child, &linkbus->devices, bus_list) {
cpos = pci_pcie_cap(child);
pci_read_config_word(child, cpos + PCI_EXP_LNKCTL, &reg16);
child_reg[PCI_FUNC(child->devfn)] = reg16;
if (same_clock)
reg16 |= PCI_EXP_LNKCTL_CCC;
else
reg16 &= ~PCI_EXP_LNKCTL_CCC;
pci_write_config_word(child, cpos + PCI_EXP_LNKCTL, reg16);
}
/* Configure upstream component */
pci_read_config_word(parent, ppos + PCI_EXP_LNKCTL, &reg16);
parent_reg = reg16;
if (same_clock)
reg16 |= PCI_EXP_LNKCTL_CCC;
else
reg16 &= ~PCI_EXP_LNKCTL_CCC;
pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, reg16);
/* Retrain link */
reg16 |= PCI_EXP_LNKCTL_RL;
pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, reg16);
/* Wait for link training end. Break out after waiting for timeout */
start_jiffies = jiffies;
for (;;) {
pci_read_config_word(parent, ppos + PCI_EXP_LNKSTA, &reg16);
if (!(reg16 & PCI_EXP_LNKSTA_LT))
break;
if (time_after(jiffies, start_jiffies + LINK_RETRAIN_TIMEOUT))
break;
msleep(1);
}
if (!(reg16 & PCI_EXP_LNKSTA_LT))
return;
/* Training failed. Restore common clock configurations */
dev_printk(KERN_ERR, &parent->dev,
"ASPM: Could not configure common clock\n");
list_for_each_entry(child, &linkbus->devices, bus_list) {
cpos = pci_pcie_cap(child);
pci_write_config_word(child, cpos + PCI_EXP_LNKCTL,
child_reg[PCI_FUNC(child->devfn)]);
}
pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, parent_reg);
}
/* Convert L0s latency encoding to ns */
static u32 calc_l0s_latency(u32 encoding)
{
if (encoding == 0x7)
return (5 * 1000); /* > 4us */
return (64 << encoding);
}
/* Convert L0s acceptable latency encoding to ns */
static u32 calc_l0s_acceptable(u32 encoding)
{
if (encoding == 0x7)
return -1U;
return (64 << encoding);
}
/* Convert L1 latency encoding to ns */
static u32 calc_l1_latency(u32 encoding)
{
if (encoding == 0x7)
return (65 * 1000); /* > 64us */
return (1000 << encoding);
}
/* Convert L1 acceptable latency encoding to ns */
static u32 calc_l1_acceptable(u32 encoding)
{
if (encoding == 0x7)
return -1U;
return (1000 << encoding);
}
struct aspm_register_info {
u32 support:2;
u32 enabled:2;
u32 latency_encoding_l0s;
u32 latency_encoding_l1;
};
static void pcie_get_aspm_reg(struct pci_dev *pdev,
struct aspm_register_info *info)
{
int pos;
u16 reg16;
u32 reg32;
pos = pci_pcie_cap(pdev);
pci_read_config_dword(pdev, pos + PCI_EXP_LNKCAP, &reg32);
info->support = (reg32 & PCI_EXP_LNKCAP_ASPMS) >> 10;
info->latency_encoding_l0s = (reg32 & PCI_EXP_LNKCAP_L0SEL) >> 12;
info->latency_encoding_l1 = (reg32 & PCI_EXP_LNKCAP_L1EL) >> 15;
pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &reg16);
info->enabled = reg16 & PCI_EXP_LNKCTL_ASPMC;
}
static void pcie_aspm_check_latency(struct pci_dev *endpoint)
{
u32 latency, l1_switch_latency = 0;
struct aspm_latency *acceptable;
struct pcie_link_state *link;
/* Device not in D0 doesn't need latency check */
if ((endpoint->current_state != PCI_D0) &&
(endpoint->current_state != PCI_UNKNOWN))
return;
link = endpoint->bus->self->link_state;
acceptable = &link->acceptable[PCI_FUNC(endpoint->devfn)];
while (link) {
/* Check upstream direction L0s latency */
if ((link->aspm_capable & ASPM_STATE_L0S_UP) &&
(link->latency_up.l0s > acceptable->l0s))
link->aspm_capable &= ~ASPM_STATE_L0S_UP;
/* Check downstream direction L0s latency */
if ((link->aspm_capable & ASPM_STATE_L0S_DW) &&
(link->latency_dw.l0s > acceptable->l0s))
link->aspm_capable &= ~ASPM_STATE_L0S_DW;
/*
* Check L1 latency.
* Every switch on the path to root complex need 1
* more microsecond for L1. Spec doesn't mention L0s.
*/
latency = max_t(u32, link->latency_up.l1, link->latency_dw.l1);
if ((link->aspm_capable & ASPM_STATE_L1) &&
(latency + l1_switch_latency > acceptable->l1))
link->aspm_capable &= ~ASPM_STATE_L1;
l1_switch_latency += 1000;
link = link->parent;
}
}
static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
{
struct pci_dev *child, *parent = link->pdev;
struct pci_bus *linkbus = parent->subordinate;
struct aspm_register_info upreg, dwreg;
if (blacklist) {
/* Set enabled/disable so that we will disable ASPM later */
link->aspm_enabled = ASPM_STATE_ALL;
link->aspm_disable = ASPM_STATE_ALL;
return;
}
/* Configure common clock before checking latencies */
pcie_aspm_configure_common_clock(link);
/* Get upstream/downstream components' register state */
pcie_get_aspm_reg(parent, &upreg);
child = list_entry(linkbus->devices.next, struct pci_dev, bus_list);
pcie_get_aspm_reg(child, &dwreg);
/*
* Setup L0s state
*
* Note that we must not enable L0s in either direction on a
* given link unless components on both sides of the link each
* support L0s.
*/
if (dwreg.support & upreg.support & PCIE_LINK_STATE_L0S)
link->aspm_support |= ASPM_STATE_L0S;
if (dwreg.enabled & PCIE_LINK_STATE_L0S)
link->aspm_enabled |= ASPM_STATE_L0S_UP;
if (upreg.enabled & PCIE_LINK_STATE_L0S)
link->aspm_enabled |= ASPM_STATE_L0S_DW;
link->latency_up.l0s = calc_l0s_latency(upreg.latency_encoding_l0s);
link->latency_dw.l0s = calc_l0s_latency(dwreg.latency_encoding_l0s);
/* Setup L1 state */
if (upreg.support & dwreg.support & PCIE_LINK_STATE_L1)
link->aspm_support |= ASPM_STATE_L1;
if (upreg.enabled & dwreg.enabled & PCIE_LINK_STATE_L1)
link->aspm_enabled |= ASPM_STATE_L1;
link->latency_up.l1 = calc_l1_latency(upreg.latency_encoding_l1);
link->latency_dw.l1 = calc_l1_latency(dwreg.latency_encoding_l1);
/* Save default state */
link->aspm_default = link->aspm_enabled;
/* Setup initial capable state. Will be updated later */
link->aspm_capable = link->aspm_support;
/*
* If the downstream component has pci bridge function, don't
* do ASPM for now.
*/
list_for_each_entry(child, &linkbus->devices, bus_list) {
if (child->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
link->aspm_disable = ASPM_STATE_ALL;
break;
}
}
/* Get and check endpoint acceptable latencies */
list_for_each_entry(child, &linkbus->devices, bus_list) {
int pos;
u32 reg32, encoding;
struct aspm_latency *acceptable =
&link->acceptable[PCI_FUNC(child->devfn)];
if (child->pcie_type != PCI_EXP_TYPE_ENDPOINT &&
child->pcie_type != PCI_EXP_TYPE_LEG_END)
continue;
pos = pci_pcie_cap(child);
pci_read_config_dword(child, pos + PCI_EXP_DEVCAP, &reg32);
/* Calculate endpoint L0s acceptable latency */
encoding = (reg32 & PCI_EXP_DEVCAP_L0S) >> 6;
acceptable->l0s = calc_l0s_acceptable(encoding);
/* Calculate endpoint L1 acceptable latency */
encoding = (reg32 & PCI_EXP_DEVCAP_L1) >> 9;
acceptable->l1 = calc_l1_acceptable(encoding);
pcie_aspm_check_latency(child);
}
}
static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
{
u16 reg16;
int pos = pci_pcie_cap(pdev);
pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &reg16);
reg16 &= ~0x3;
reg16 |= val;
pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16);
}
static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
{
u32 upstream = 0, dwstream = 0;
struct pci_dev *child, *parent = link->pdev;
struct pci_bus *linkbus = parent->subordinate;
/* Nothing to do if the link is already in the requested state */
state &= (link->aspm_capable & ~link->aspm_disable);
if (link->aspm_enabled == state)
return;
/* Convert ASPM state to upstream/downstream ASPM register state */
if (state & ASPM_STATE_L0S_UP)
dwstream |= PCIE_LINK_STATE_L0S;
if (state & ASPM_STATE_L0S_DW)
upstream |= PCIE_LINK_STATE_L0S;
if (state & ASPM_STATE_L1) {
upstream |= PCIE_LINK_STATE_L1;
dwstream |= PCIE_LINK_STATE_L1;
}
/*
* Spec 2.0 suggests all functions should be configured the
* same setting for ASPM. Enabling ASPM L1 should be done in
* upstream component first and then downstream, and vice
* versa for disabling ASPM L1. Spec doesn't mention L0S.
*/
if (state & ASPM_STATE_L1)
pcie_config_aspm_dev(parent, upstream);
list_for_each_entry(child, &linkbus->devices, bus_list)
pcie_config_aspm_dev(child, dwstream);
if (!(state & ASPM_STATE_L1))
pcie_config_aspm_dev(parent, upstream);
link->aspm_enabled = state;
}
static void pcie_config_aspm_path(struct pcie_link_state *link)
{
while (link) {
pcie_config_aspm_link(link, policy_to_aspm_state(link));
link = link->parent;
}
}
static void free_link_state(struct pcie_link_state *link)
{
link->pdev->link_state = NULL;
kfree(link);
}
static int pcie_aspm_sanity_check(struct pci_dev *pdev)
{
struct pci_dev *child;
int pos;
u32 reg32;
if (aspm_clear_state)
return -EINVAL;
/*
* Some functions in a slot might not all be PCIe functions,
* very strange. Disable ASPM for the whole slot
*/
list_for_each_entry(child, &pdev->subordinate->devices, bus_list) {
pos = pci_pcie_cap(child);
if (!pos)
return -EINVAL;
/*
* Disable ASPM for pre-1.1 PCIe device, we follow MS to use
* RBER bit to determine if a function is 1.1 version device
*/
pci_read_config_dword(child, pos + PCI_EXP_DEVCAP, &reg32);
if (!(reg32 & PCI_EXP_DEVCAP_RBER) && !aspm_force) {
dev_printk(KERN_INFO, &child->dev, "disabling ASPM"
" on pre-1.1 PCIe device. You can enable it"
" with 'pcie_aspm=force'\n");
return -EINVAL;
}
}
return 0;
}
static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
{
struct pcie_link_state *link;
link = kzalloc(sizeof(*link), GFP_KERNEL);
if (!link)
return NULL;
INIT_LIST_HEAD(&link->sibling);
INIT_LIST_HEAD(&link->children);
INIT_LIST_HEAD(&link->link);
link->pdev = pdev;
if (pdev->pcie_type == PCI_EXP_TYPE_DOWNSTREAM) {
struct pcie_link_state *parent;
parent = pdev->bus->parent->self->link_state;
if (!parent) {
kfree(link);
return NULL;
}
link->parent = parent;
list_add(&link->link, &parent->children);
}
/* Setup a pointer to the root port link */
if (!link->parent)
link->root = link;
else
link->root = link->parent->root;
list_add(&link->sibling, &link_list);
pdev->link_state = link;
return link;
}
/*
* pcie_aspm_init_link_state: Initiate PCI express link state.
* It is called after the pcie and its children devices are scaned.
* @pdev: the root port or switch downstream port
*/
void pcie_aspm_init_link_state(struct pci_dev *pdev)
{
struct pcie_link_state *link;
int blacklist = !!pcie_aspm_sanity_check(pdev);
if (!pci_is_pcie(pdev) || pdev->link_state)
return;
if (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM)
return;
if (aspm_disabled && !aspm_clear_state)
return;
/* VIA has a strange chipset, root port is under a bridge */
if (pdev->pcie_type == PCI_EXP_TYPE_ROOT_PORT &&
pdev->bus->self)
return;
down_read(&pci_bus_sem);
if (list_empty(&pdev->subordinate->devices))
goto out;
mutex_lock(&aspm_lock);
link = alloc_pcie_link_state(pdev);
if (!link)
goto unlock;
/*
* Setup initial ASPM state. Note that we need to configure
* upstream links also because capable state of them can be
* update through pcie_aspm_cap_init().
*/
pcie_aspm_cap_init(link, blacklist);
/* Setup initial Clock PM state */
pcie_clkpm_cap_init(link, blacklist);
/*
* At this stage drivers haven't had an opportunity to change the
* link policy setting. Enabling ASPM on broken hardware can cripple
* it even before the driver has had a chance to disable ASPM, so
* default to a safe level right now. If we're enabling ASPM beyond
* the BIOS's expectation, we'll do so once pci_enable_device() is
* called.
*/
if (aspm_policy != POLICY_POWERSAVE) {
pcie_config_aspm_path(link);
pcie_set_clkpm(link, policy_to_clkpm_state(link));
}
unlock:
mutex_unlock(&aspm_lock);
out:
up_read(&pci_bus_sem);
}
/* Recheck latencies and update aspm_capable for links under the root */
static void pcie_update_aspm_capable(struct pcie_link_state *root)
{
struct pcie_link_state *link;
BUG_ON(root->parent);
list_for_each_entry(link, &link_list, sibling) {
if (link->root != root)
continue;
link->aspm_capable = link->aspm_support;
}
list_for_each_entry(link, &link_list, sibling) {
struct pci_dev *child;
struct pci_bus *linkbus = link->pdev->subordinate;
if (link->root != root)
continue;
list_for_each_entry(child, &linkbus->devices, bus_list) {
if ((child->pcie_type != PCI_EXP_TYPE_ENDPOINT) &&
(child->pcie_type != PCI_EXP_TYPE_LEG_END))
continue;
pcie_aspm_check_latency(child);
}
}
}
/* @pdev: the endpoint device */
void pcie_aspm_exit_link_state(struct pci_dev *pdev)
{
struct pci_dev *parent = pdev->bus->self;
struct pcie_link_state *link, *root, *parent_link;
if ((aspm_disabled && !aspm_clear_state) || !pci_is_pcie(pdev) ||
!parent || !parent->link_state)
return;
if ((parent->pcie_type != PCI_EXP_TYPE_ROOT_PORT) &&
(parent->pcie_type != PCI_EXP_TYPE_DOWNSTREAM))
return;
down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
/*
* All PCIe functions are in one slot, remove one function will remove
* the whole slot, so just wait until we are the last function left.
*/
if (!list_is_last(&pdev->bus_list, &parent->subordinate->devices))
goto out;
link = parent->link_state;
root = link->root;
parent_link = link->parent;
/* All functions are removed, so just disable ASPM for the link */
pcie_config_aspm_link(link, 0);
list_del(&link->sibling);
list_del(&link->link);
/* Clock PM is for endpoint device */
free_link_state(link);
/* Recheck latencies and configure upstream links */
if (parent_link) {
pcie_update_aspm_capable(root);
pcie_config_aspm_path(parent_link);
}
out:
mutex_unlock(&aspm_lock);
up_read(&pci_bus_sem);
}
/* @pdev: the root port or switch downstream port */
void pcie_aspm_pm_state_change(struct pci_dev *pdev)
{
struct pcie_link_state *link = pdev->link_state;
if (aspm_disabled || !pci_is_pcie(pdev) || !link)
return;
if ((pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT) &&
(pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM))
return;
/*
* Devices changed PM state, we should recheck if latency
* meets all functions' requirement
*/
down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
pcie_update_aspm_capable(link->root);
pcie_config_aspm_path(link);
mutex_unlock(&aspm_lock);
up_read(&pci_bus_sem);
}
void pcie_aspm_powersave_config_link(struct pci_dev *pdev)
{
struct pcie_link_state *link = pdev->link_state;
if (aspm_disabled || !pci_is_pcie(pdev) || !link)
return;
if (aspm_policy != POLICY_POWERSAVE)
return;
if ((pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT) &&
(pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM))
return;
down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
pcie_config_aspm_path(link);
pcie_set_clkpm(link, policy_to_clkpm_state(link));
mutex_unlock(&aspm_lock);
up_read(&pci_bus_sem);
}
/*
* pci_disable_link_state - disable pci device's link state, so the link will
* never enter specific states
*/
void pci_disable_link_state(struct pci_dev *pdev, int state)
{
struct pci_dev *parent = pdev->bus->self;
struct pcie_link_state *link;
if (aspm_disabled || !pci_is_pcie(pdev))
return;
if (pdev->pcie_type == PCI_EXP_TYPE_ROOT_PORT ||
pdev->pcie_type == PCI_EXP_TYPE_DOWNSTREAM)
parent = pdev;
if (!parent || !parent->link_state)
return;
down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
link = parent->link_state;
if (state & PCIE_LINK_STATE_L0S)
link->aspm_disable |= ASPM_STATE_L0S;
if (state & PCIE_LINK_STATE_L1)
link->aspm_disable |= ASPM_STATE_L1;
pcie_config_aspm_link(link, policy_to_aspm_state(link));
if (state & PCIE_LINK_STATE_CLKPM) {
link->clkpm_capable = 0;
pcie_set_clkpm(link, 0);
}
mutex_unlock(&aspm_lock);
up_read(&pci_bus_sem);
}
EXPORT_SYMBOL(pci_disable_link_state);
static int pcie_aspm_set_policy(const char *val, struct kernel_param *kp)
{
int i;
struct pcie_link_state *link;
if (aspm_disabled)
return -EPERM;
for (i = 0; i < ARRAY_SIZE(policy_str); i++)
if (!strncmp(val, policy_str[i], strlen(policy_str[i])))
break;
if (i >= ARRAY_SIZE(policy_str))
return -EINVAL;
if (i == aspm_policy)
return 0;
down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
aspm_policy = i;
list_for_each_entry(link, &link_list, sibling) {
pcie_config_aspm_link(link, policy_to_aspm_state(link));
pcie_set_clkpm(link, policy_to_clkpm_state(link));
}
mutex_unlock(&aspm_lock);
up_read(&pci_bus_sem);
return 0;
}
static int pcie_aspm_get_policy(char *buffer, struct kernel_param *kp)
{
int i, cnt = 0;
for (i = 0; i < ARRAY_SIZE(policy_str); i++)
if (i == aspm_policy)
cnt += sprintf(buffer + cnt, "[%s] ", policy_str[i]);
else
cnt += sprintf(buffer + cnt, "%s ", policy_str[i]);
return cnt;
}
module_param_call(policy, pcie_aspm_set_policy, pcie_aspm_get_policy,
NULL, 0644);
#ifdef CONFIG_PCIEASPM_DEBUG
static ssize_t link_state_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct pci_dev *pci_device = to_pci_dev(dev);
struct pcie_link_state *link_state = pci_device->link_state;
return sprintf(buf, "%d\n", link_state->aspm_enabled);
}
static ssize_t link_state_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t n)
{
struct pci_dev *pdev = to_pci_dev(dev);
struct pcie_link_state *link, *root = pdev->link_state->root;
u32 val = buf[0] - '0', state = 0;
if (aspm_disabled)
return -EPERM;
if (n < 1 || val > 3)
return -EINVAL;
/* Convert requested state to ASPM state */
if (val & PCIE_LINK_STATE_L0S)
state |= ASPM_STATE_L0S;
if (val & PCIE_LINK_STATE_L1)
state |= ASPM_STATE_L1;
down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
list_for_each_entry(link, &link_list, sibling) {
if (link->root != root)
continue;
pcie_config_aspm_link(link, state);
}
mutex_unlock(&aspm_lock);
up_read(&pci_bus_sem);
return n;
}
static ssize_t clk_ctl_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct pci_dev *pci_device = to_pci_dev(dev);
struct pcie_link_state *link_state = pci_device->link_state;
return sprintf(buf, "%d\n", link_state->clkpm_enabled);
}
static ssize_t clk_ctl_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t n)
{
struct pci_dev *pdev = to_pci_dev(dev);
int state;
if (n < 1)
return -EINVAL;
state = buf[0]-'0';
down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
pcie_set_clkpm_nocheck(pdev->link_state, !!state);
mutex_unlock(&aspm_lock);
up_read(&pci_bus_sem);
return n;
}
static DEVICE_ATTR(link_state, 0644, link_state_show, link_state_store);
static DEVICE_ATTR(clk_ctl, 0644, clk_ctl_show, clk_ctl_store);
static char power_group[] = "power";
void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev)
{
struct pcie_link_state *link_state = pdev->link_state;
if (!pci_is_pcie(pdev) ||
(pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM) || !link_state)
return;
if (link_state->aspm_support)
sysfs_add_file_to_group(&pdev->dev.kobj,
&dev_attr_link_state.attr, power_group);
if (link_state->clkpm_capable)
sysfs_add_file_to_group(&pdev->dev.kobj,
&dev_attr_clk_ctl.attr, power_group);
}
void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev)
{
struct pcie_link_state *link_state = pdev->link_state;
if (!pci_is_pcie(pdev) ||
(pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM) || !link_state)
return;
if (link_state->aspm_support)
sysfs_remove_file_from_group(&pdev->dev.kobj,
&dev_attr_link_state.attr, power_group);
if (link_state->clkpm_capable)
sysfs_remove_file_from_group(&pdev->dev.kobj,
&dev_attr_clk_ctl.attr, power_group);
}
#endif
static int __init pcie_aspm_disable(char *str)
{
if (!strcmp(str, "off")) {
aspm_disabled = 1;
aspm_support_enabled = false;
printk(KERN_INFO "PCIe ASPM is disabled\n");
} else if (!strcmp(str, "force")) {
aspm_force = 1;
printk(KERN_INFO "PCIe ASPM is forcedly enabled\n");
}
return 1;
}
__setup("pcie_aspm=", pcie_aspm_disable);
void pcie_clear_aspm(void)
{
if (!aspm_force)
aspm_clear_state = 1;
}
void pcie_no_aspm(void)
{
if (!aspm_force)
aspm_disabled = 1;
}
/**
* pcie_aspm_enabled - is PCIe ASPM enabled?
*
* Returns true if ASPM has not been disabled by the command-line option
* pcie_aspm=off.
**/
int pcie_aspm_enabled(void)
{
return !aspm_disabled;
}
EXPORT_SYMBOL(pcie_aspm_enabled);
bool pcie_aspm_support_enabled(void)
{
return aspm_support_enabled;
}
EXPORT_SYMBOL(pcie_aspm_support_enabled);