linux/drivers/pci/pcie/aspm.c

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/*
* 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/pci-aspm.h>
#include "../pci.h"
#ifdef MODULE_PARAM_PREFIX
#undef MODULE_PARAM_PREFIX
#endif
#define MODULE_PARAM_PREFIX "pcie_aspm."
struct endpoint_state {
unsigned int l0s_acceptable_latency;
unsigned int l1_acceptable_latency;
};
struct pcie_link_state {
struct list_head sibiling;
struct pci_dev *pdev;
/* ASPM state */
unsigned int support_state;
unsigned int enabled_state;
unsigned int bios_aspm_state;
/* upstream component */
unsigned int l0s_upper_latency;
unsigned int l1_upper_latency;
/* downstream component */
unsigned int l0s_down_latency;
unsigned int l1_down_latency;
/* Clock PM state*/
unsigned int clk_pm_capable;
unsigned int clk_pm_enabled;
unsigned int bios_clk_state;
/*
* A pcie downstream port only has one slot under it, so at most there
* are 8 functions
*/
struct endpoint_state endpoints[8];
};
static int aspm_disabled, aspm_force;
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"
};
static int policy_to_aspm_state(struct pci_dev *pdev)
{
struct pcie_link_state *link_state = pdev->link_state;
switch (aspm_policy) {
case POLICY_PERFORMANCE:
/* Disable ASPM and Clock PM */
return 0;
case POLICY_POWERSAVE:
/* Enable ASPM L0s/L1 */
return PCIE_LINK_STATE_L0S|PCIE_LINK_STATE_L1;
case POLICY_DEFAULT:
return link_state->bios_aspm_state;
}
return 0;
}
static int policy_to_clkpm_state(struct pci_dev *pdev)
{
struct pcie_link_state *link_state = pdev->link_state;
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_state->bios_clk_state;
}
return 0;
}
static void pcie_set_clock_pm(struct pci_dev *pdev, int enable)
{
struct pci_dev *child_dev;
int pos;
u16 reg16;
struct pcie_link_state *link_state = pdev->link_state;
list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
if (!pos)
return;
pci_read_config_word(child_dev, 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_dev, pos + PCI_EXP_LNKCTL, reg16);
}
link_state->clk_pm_enabled = !!enable;
}
static void pcie_check_clock_pm(struct pci_dev *pdev)
{
int pos;
u32 reg32;
u16 reg16;
int capable = 1, enabled = 1;
struct pci_dev *child_dev;
struct pcie_link_state *link_state = pdev->link_state;
/* All functions should have the same cap and state, take the worst */
list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
if (!pos)
return;
pci_read_config_dword(child_dev, pos + PCI_EXP_LNKCAP, &reg32);
if (!(reg32 & PCI_EXP_LNKCAP_CLKPM)) {
capable = 0;
enabled = 0;
break;
}
pci_read_config_word(child_dev, pos + PCI_EXP_LNKCTL, &reg16);
if (!(reg16 & PCI_EXP_LNKCTL_CLKREQ_EN))
enabled = 0;
}
link_state->clk_pm_capable = capable;
link_state->clk_pm_enabled = enabled;
link_state->bios_clk_state = enabled;
pcie_set_clock_pm(pdev, policy_to_clkpm_state(pdev));
}
/*
* 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 pci_dev *pdev)
{
int pos, child_pos, i = 0;
u16 reg16 = 0;
struct pci_dev *child_dev;
int same_clock = 1;
unsigned long start_jiffies;
u16 child_regs[8], parent_reg;
/*
* all functions of a slot should have the same Slot Clock
* Configuration, so just check one function
* */
child_dev = list_entry(pdev->subordinate->devices.next, struct pci_dev,
bus_list);
BUG_ON(!child_dev->is_pcie);
/* Check downstream component if bit Slot Clock Configuration is 1 */
child_pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
pci_read_config_word(child_dev, child_pos + PCI_EXP_LNKSTA, &reg16);
if (!(reg16 & PCI_EXP_LNKSTA_SLC))
same_clock = 0;
/* Check upstream component if bit Slot Clock Configuration is 1 */
pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
pci_read_config_word(pdev, pos + PCI_EXP_LNKSTA, &reg16);
if (!(reg16 & PCI_EXP_LNKSTA_SLC))
same_clock = 0;
/* Configure downstream component, all functions */
list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
child_pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
pci_read_config_word(child_dev, child_pos + PCI_EXP_LNKCTL,
&reg16);
child_regs[i] = reg16;
if (same_clock)
reg16 |= PCI_EXP_LNKCTL_CCC;
else
reg16 &= ~PCI_EXP_LNKCTL_CCC;
pci_write_config_word(child_dev, child_pos + PCI_EXP_LNKCTL,
reg16);
i++;
}
/* Configure upstream component */
pci_read_config_word(pdev, pos + 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(pdev, pos + PCI_EXP_LNKCTL, reg16);
/* retrain link */
reg16 |= PCI_EXP_LNKCTL_RL;
pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16);
/* Wait for link training end */
/* break out after waiting for 1 second */
start_jiffies = jiffies;
while ((jiffies - start_jiffies) < HZ) {
pci_read_config_word(pdev, pos + PCI_EXP_LNKSTA, &reg16);
if (!(reg16 & PCI_EXP_LNKSTA_LT))
break;
cpu_relax();
}
/* training failed -> recover */
if ((jiffies - start_jiffies) >= HZ) {
dev_printk (KERN_ERR, &pdev->dev, "ASPM: Could not configure"
" common clock\n");
i = 0;
list_for_each_entry(child_dev, &pdev->subordinate->devices,
bus_list) {
child_pos = pci_find_capability(child_dev,
PCI_CAP_ID_EXP);
pci_write_config_word(child_dev,
child_pos + PCI_EXP_LNKCTL,
child_regs[i]);
i++;
}
pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, parent_reg);
}
}
/*
* calc_L0S_latency: Convert L0s latency encoding to ns
*/
static unsigned int calc_L0S_latency(unsigned int latency_encoding, int ac)
{
unsigned int ns = 64;
if (latency_encoding == 0x7) {
if (ac)
ns = -1U;
else
ns = 5*1000; /* > 4us */
} else
ns *= (1 << latency_encoding);
return ns;
}
/*
* calc_L1_latency: Convert L1 latency encoding to ns
*/
static unsigned int calc_L1_latency(unsigned int latency_encoding, int ac)
{
unsigned int ns = 1000;
if (latency_encoding == 0x7) {
if (ac)
ns = -1U;
else
ns = 65*1000; /* > 64us */
} else
ns *= (1 << latency_encoding);
return ns;
}
static void pcie_aspm_get_cap_device(struct pci_dev *pdev, u32 *state,
unsigned int *l0s, unsigned int *l1, unsigned int *enabled)
{
int pos;
u16 reg16;
u32 reg32;
unsigned int latency;
pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
pci_read_config_dword(pdev, pos + PCI_EXP_LNKCAP, &reg32);
*state = (reg32 & PCI_EXP_LNKCAP_ASPMS) >> 10;
if (*state != PCIE_LINK_STATE_L0S &&
*state != (PCIE_LINK_STATE_L1|PCIE_LINK_STATE_L0S))
*state = 0;
if (*state == 0)
return;
latency = (reg32 & PCI_EXP_LNKCAP_L0SEL) >> 12;
*l0s = calc_L0S_latency(latency, 0);
if (*state & PCIE_LINK_STATE_L1) {
latency = (reg32 & PCI_EXP_LNKCAP_L1EL) >> 15;
*l1 = calc_L1_latency(latency, 0);
}
pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &reg16);
*enabled = reg16 & (PCIE_LINK_STATE_L0S|PCIE_LINK_STATE_L1);
}
static void pcie_aspm_cap_init(struct pci_dev *pdev)
{
struct pci_dev *child_dev;
u32 state, tmp;
struct pcie_link_state *link_state = pdev->link_state;
/* upstream component states */
pcie_aspm_get_cap_device(pdev, &link_state->support_state,
&link_state->l0s_upper_latency,
&link_state->l1_upper_latency,
&link_state->enabled_state);
/* downstream component states, all functions have the same setting */
child_dev = list_entry(pdev->subordinate->devices.next, struct pci_dev,
bus_list);
pcie_aspm_get_cap_device(child_dev, &state,
&link_state->l0s_down_latency,
&link_state->l1_down_latency,
&tmp);
link_state->support_state &= state;
if (!link_state->support_state)
return;
link_state->enabled_state &= link_state->support_state;
link_state->bios_aspm_state = link_state->enabled_state;
/* ENDPOINT states*/
list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
int pos;
u32 reg32;
unsigned int latency;
struct endpoint_state *ep_state =
&link_state->endpoints[PCI_FUNC(child_dev->devfn)];
if (child_dev->pcie_type != PCI_EXP_TYPE_ENDPOINT &&
child_dev->pcie_type != PCI_EXP_TYPE_LEG_END)
continue;
pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
pci_read_config_dword(child_dev, pos + PCI_EXP_DEVCAP, &reg32);
latency = (reg32 & PCI_EXP_DEVCAP_L0S) >> 6;
latency = calc_L0S_latency(latency, 1);
ep_state->l0s_acceptable_latency = latency;
if (link_state->support_state & PCIE_LINK_STATE_L1) {
latency = (reg32 & PCI_EXP_DEVCAP_L1) >> 9;
latency = calc_L1_latency(latency, 1);
ep_state->l1_acceptable_latency = latency;
}
}
}
static unsigned int __pcie_aspm_check_state_one(struct pci_dev *pdev,
unsigned int state)
{
struct pci_dev *parent_dev, *tmp_dev;
unsigned int latency, l1_latency = 0;
struct pcie_link_state *link_state;
struct endpoint_state *ep_state;
parent_dev = pdev->bus->self;
link_state = parent_dev->link_state;
state &= link_state->support_state;
if (state == 0)
return 0;
ep_state = &link_state->endpoints[PCI_FUNC(pdev->devfn)];
/*
* Check latency for endpoint device.
* TBD: The latency from the endpoint to root complex vary per
* switch's upstream link state above the device. Here we just do a
* simple check which assumes all links above the device can be in L1
* state, that is we just consider the worst case. If switch's upstream
* link can't be put into L0S/L1, then our check is too strictly.
*/
tmp_dev = pdev;
while (state & (PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1)) {
parent_dev = tmp_dev->bus->self;
link_state = parent_dev->link_state;
if (state & PCIE_LINK_STATE_L0S) {
latency = max_t(unsigned int,
link_state->l0s_upper_latency,
link_state->l0s_down_latency);
if (latency > ep_state->l0s_acceptable_latency)
state &= ~PCIE_LINK_STATE_L0S;
}
if (state & PCIE_LINK_STATE_L1) {
latency = max_t(unsigned int,
link_state->l1_upper_latency,
link_state->l1_down_latency);
if (latency + l1_latency >
ep_state->l1_acceptable_latency)
state &= ~PCIE_LINK_STATE_L1;
}
if (!parent_dev->bus->self) /* parent_dev is a root port */
break;
else {
/*
* parent_dev is the downstream port of a switch, make
* tmp_dev the upstream port of the switch
*/
tmp_dev = parent_dev->bus->self;
/*
* every switch on the path to root complex need 1 more
* microsecond for L1. Spec doesn't mention L0S.
*/
if (state & PCIE_LINK_STATE_L1)
l1_latency += 1000;
}
}
return state;
}
static unsigned int pcie_aspm_check_state(struct pci_dev *pdev,
unsigned int state)
{
struct pci_dev *child_dev;
/* If no child, disable the link */
if (list_empty(&pdev->subordinate->devices))
return 0;
list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
if (child_dev->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
/*
* If downstream component of a link is pci bridge, we
* disable ASPM for now for the link
* */
state = 0;
break;
}
if ((child_dev->pcie_type != PCI_EXP_TYPE_ENDPOINT &&
child_dev->pcie_type != PCI_EXP_TYPE_LEG_END))
continue;
/* Device not in D0 doesn't need check latency */
if (child_dev->current_state == PCI_D1 ||
child_dev->current_state == PCI_D2 ||
child_dev->current_state == PCI_D3hot ||
child_dev->current_state == PCI_D3cold)
continue;
state = __pcie_aspm_check_state_one(child_dev, state);
}
return state;
}
static void __pcie_aspm_config_one_dev(struct pci_dev *pdev, unsigned int state)
{
u16 reg16;
int pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &reg16);
reg16 &= ~0x3;
reg16 |= state;
pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16);
}
static void __pcie_aspm_config_link(struct pci_dev *pdev, unsigned int state)
{
struct pci_dev *child_dev;
int valid = 1;
struct pcie_link_state *link_state = pdev->link_state;
/*
* if the downstream component has pci bridge function, don't do ASPM
* now
*/
list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
if (child_dev->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
valid = 0;
break;
}
}
if (!valid)
return;
/*
* 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 & PCIE_LINK_STATE_L1)
__pcie_aspm_config_one_dev(pdev, state);
list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list)
__pcie_aspm_config_one_dev(child_dev, state);
if (!(state & PCIE_LINK_STATE_L1))
__pcie_aspm_config_one_dev(pdev, state);
link_state->enabled_state = state;
}
static void __pcie_aspm_configure_link_state(struct pci_dev *pdev,
unsigned int state)
{
struct pcie_link_state *link_state = pdev->link_state;
if (link_state->support_state == 0)
return;
state &= PCIE_LINK_STATE_L0S|PCIE_LINK_STATE_L1;
/* state 0 means disabling aspm */
state = pcie_aspm_check_state(pdev, state);
if (link_state->enabled_state == state)
return;
__pcie_aspm_config_link(pdev, state);
}
/*
* pcie_aspm_configure_link_state: enable/disable PCI express link state
* @pdev: the root port or switch downstream port
*/
static void pcie_aspm_configure_link_state(struct pci_dev *pdev,
unsigned int state)
{
down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
__pcie_aspm_configure_link_state(pdev, state);
mutex_unlock(&aspm_lock);
up_read(&pci_bus_sem);
}
static void free_link_state(struct pci_dev *pdev)
{
kfree(pdev->link_state);
pdev->link_state = NULL;
}
static int pcie_aspm_sanity_check(struct pci_dev *pdev)
{
struct pci_dev *child_dev;
int child_pos;
u32 reg32;
/*
* Some functions in a slot might not all be PCIE functions, very
* strange. Disable ASPM for the whole slot
*/
list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
child_pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
if (!child_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_dev, child_pos + PCI_EXP_DEVCAP,
&reg32);
if (!(reg32 & PCI_EXP_DEVCAP_RBER) && !aspm_force) {
dev_printk(KERN_INFO, &child_dev->dev, "disabling ASPM"
" on pre-1.1 PCIe device. You can enable it"
" with 'pcie_aspm=force'\n");
return -EINVAL;
}
}
return 0;
}
/*
* 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)
{
unsigned int state;
struct pcie_link_state *link_state;
int error = 0;
if (aspm_disabled || !pdev->is_pcie || pdev->link_state)
return;
if (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM)
return;
down_read(&pci_bus_sem);
if (list_empty(&pdev->subordinate->devices))
goto out;
if (pcie_aspm_sanity_check(pdev))
goto out;
mutex_lock(&aspm_lock);
link_state = kzalloc(sizeof(*link_state), GFP_KERNEL);
if (!link_state)
goto unlock_out;
pdev->link_state = link_state;
pcie_aspm_configure_common_clock(pdev);
pcie_aspm_cap_init(pdev);
/* config link state to avoid BIOS error */
state = pcie_aspm_check_state(pdev, policy_to_aspm_state(pdev));
__pcie_aspm_config_link(pdev, state);
pcie_check_clock_pm(pdev);
link_state->pdev = pdev;
list_add(&link_state->sibiling, &link_list);
unlock_out:
if (error)
free_link_state(pdev);
mutex_unlock(&aspm_lock);
out:
up_read(&pci_bus_sem);
}
/* @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_state = parent->link_state;
if (aspm_disabled || !pdev->is_pcie || !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 the whole slot, so just wait
*/
if (!list_empty(&parent->subordinate->devices))
goto out;
/* All functions are removed, so just disable ASPM for the link */
__pcie_aspm_config_one_dev(parent, 0);
list_del(&link_state->sibiling);
/* Clock PM is for endpoint device */
free_link_state(parent);
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_state = pdev->link_state;
if (aspm_disabled || !pdev->is_pcie || !pdev->link_state)
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
*/
pcie_aspm_configure_link_state(pdev, link_state->enabled_state);
}
/*
* 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_state;
if (aspm_disabled || !pdev->is_pcie)
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_state = parent->link_state;
link_state->support_state &=
~(state & (PCIE_LINK_STATE_L0S|PCIE_LINK_STATE_L1));
if (state & PCIE_LINK_STATE_CLKPM)
link_state->clk_pm_capable = 0;
__pcie_aspm_configure_link_state(parent, link_state->enabled_state);
if (!link_state->clk_pm_capable && link_state->clk_pm_enabled)
pcie_set_clock_pm(parent, 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 pci_dev *pdev;
struct pcie_link_state *link_state;
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_state, &link_list, sibiling) {
pdev = link_state->pdev;
__pcie_aspm_configure_link_state(pdev,
policy_to_aspm_state(pdev));
if (link_state->clk_pm_capable &&
link_state->clk_pm_enabled != policy_to_clkpm_state(pdev))
pcie_set_clock_pm(pdev, policy_to_clkpm_state(pdev));
}
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->enabled_state);
}
static ssize_t link_state_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t n)
{
struct pci_dev *pci_device = to_pci_dev(dev);
int state;
if (n < 1)
return -EINVAL;
state = buf[0]-'0';
if (state >= 0 && state <= 3) {
/* setup link aspm state */
pcie_aspm_configure_link_state(pci_device, state);
return n;
}
return -EINVAL;
}
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->clk_pm_enabled);
}
static ssize_t clk_ctl_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t n)
{
struct pci_dev *pci_device = 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_clock_pm(pci_device, !!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 (!pdev->is_pcie || (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM) || !link_state)
return;
if (link_state->support_state)
sysfs_add_file_to_group(&pdev->dev.kobj,
&dev_attr_link_state.attr, power_group);
if (link_state->clk_pm_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 (!pdev->is_pcie || (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM) || !link_state)
return;
if (link_state->support_state)
sysfs_remove_file_from_group(&pdev->dev.kobj,
&dev_attr_link_state.attr, power_group);
if (link_state->clk_pm_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;
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_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);