v4.19.13 snapshot.
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
new file mode 100644
index 0000000..f78860c
--- /dev/null
+++ b/drivers/pci/pcie/aspm.c
@@ -0,0 +1,1301 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Enable 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_L1_1 (8) /* ASPM L1.1 state */
+#define ASPM_STATE_L1_2 (0x10) /* ASPM L1.2 state */
+#define ASPM_STATE_L1_1_PCIPM (0x20) /* PCI PM L1.1 state */
+#define ASPM_STATE_L1_2_PCIPM (0x40) /* PCI PM L1.2 state */
+#define ASPM_STATE_L1_SS_PCIPM (ASPM_STATE_L1_1_PCIPM | ASPM_STATE_L1_2_PCIPM)
+#define ASPM_STATE_L1_2_MASK (ASPM_STATE_L1_2 | ASPM_STATE_L1_2_PCIPM)
+#define ASPM_STATE_L1SS (ASPM_STATE_L1_1 | ASPM_STATE_L1_1_PCIPM |\
+ ASPM_STATE_L1_2_MASK)
+#define ASPM_STATE_L0S (ASPM_STATE_L0S_UP | ASPM_STATE_L0S_DW)
+#define ASPM_STATE_ALL (ASPM_STATE_L0S | ASPM_STATE_L1 | \
+ ASPM_STATE_L1SS)
+
+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 pci_dev *downstream; /* Downstream component, function 0 */
+ 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:7; /* Supported ASPM state */
+ u32 aspm_enabled:7; /* Enabled ASPM state */
+ u32 aspm_capable:7; /* Capable ASPM state with latency */
+ u32 aspm_default:7; /* Default ASPM state by BIOS */
+ u32 aspm_disable:7; /* 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];
+
+ /* L1 PM Substate info */
+ struct {
+ u32 up_cap_ptr; /* L1SS cap ptr in upstream dev */
+ u32 dw_cap_ptr; /* L1SS cap ptr in downstream dev */
+ u32 ctl1; /* value to be programmed in ctl1 */
+ u32 ctl2; /* value to be programmed in ctl2 */
+ } l1ss;
+};
+
+static int aspm_disabled, aspm_force;
+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 */
+#define POLICY_POWER_SUPERSAVE 3 /* possibly even more power saving */
+
+#ifdef CONFIG_PCIEASPM_PERFORMANCE
+static int aspm_policy = POLICY_PERFORMANCE;
+#elif defined CONFIG_PCIEASPM_POWERSAVE
+static int aspm_policy = POLICY_POWERSAVE;
+#elif defined CONFIG_PCIEASPM_POWER_SUPERSAVE
+static int aspm_policy = POLICY_POWER_SUPERSAVE;
+#else
+static int aspm_policy;
+#endif
+
+static const char *policy_str[] = {
+ [POLICY_DEFAULT] = "default",
+ [POLICY_PERFORMANCE] = "performance",
+ [POLICY_POWERSAVE] = "powersave",
+ [POLICY_POWER_SUPERSAVE] = "powersupersave"
+};
+
+#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_L0S | ASPM_STATE_L1);
+ case POLICY_POWER_SUPERSAVE:
+ /* Enable Everything */
+ 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:
+ case POLICY_POWER_SUPERSAVE:
+ /* Enable 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)
+{
+ struct pci_dev *child;
+ struct pci_bus *linkbus = link->pdev->subordinate;
+ u32 val = enable ? PCI_EXP_LNKCTL_CLKREQ_EN : 0;
+
+ list_for_each_entry(child, &linkbus->devices, bus_list)
+ pcie_capability_clear_and_set_word(child, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_CLKREQ_EN,
+ val);
+ 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 = 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 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) {
+ pcie_capability_read_dword(child, PCI_EXP_LNKCAP, ®32);
+ if (!(reg32 & PCI_EXP_LNKCAP_CLKPM)) {
+ capable = 0;
+ enabled = 0;
+ break;
+ }
+ pcie_capability_read_word(child, PCI_EXP_LNKCTL, ®16);
+ 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 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 */
+ pcie_capability_read_word(child, PCI_EXP_LNKSTA, ®16);
+ if (!(reg16 & PCI_EXP_LNKSTA_SLC))
+ same_clock = 0;
+
+ /* Check upstream component if bit Slot Clock Configuration is 1 */
+ pcie_capability_read_word(parent, PCI_EXP_LNKSTA, ®16);
+ if (!(reg16 & PCI_EXP_LNKSTA_SLC))
+ same_clock = 0;
+
+ /* Port might be already in common clock mode */
+ pcie_capability_read_word(parent, PCI_EXP_LNKCTL, ®16);
+ if (same_clock && (reg16 & PCI_EXP_LNKCTL_CCC)) {
+ bool consistent = true;
+
+ list_for_each_entry(child, &linkbus->devices, bus_list) {
+ pcie_capability_read_word(child, PCI_EXP_LNKCTL,
+ ®16);
+ if (!(reg16 & PCI_EXP_LNKCTL_CCC)) {
+ consistent = false;
+ break;
+ }
+ }
+ if (consistent)
+ return;
+ pci_warn(parent, "ASPM: current common clock configuration is broken, reconfiguring\n");
+ }
+
+ /* Configure downstream component, all functions */
+ list_for_each_entry(child, &linkbus->devices, bus_list) {
+ pcie_capability_read_word(child, PCI_EXP_LNKCTL, ®16);
+ child_reg[PCI_FUNC(child->devfn)] = reg16;
+ if (same_clock)
+ reg16 |= PCI_EXP_LNKCTL_CCC;
+ else
+ reg16 &= ~PCI_EXP_LNKCTL_CCC;
+ pcie_capability_write_word(child, PCI_EXP_LNKCTL, reg16);
+ }
+
+ /* Configure upstream component */
+ pcie_capability_read_word(parent, PCI_EXP_LNKCTL, ®16);
+ parent_reg = reg16;
+ if (same_clock)
+ reg16 |= PCI_EXP_LNKCTL_CCC;
+ else
+ reg16 &= ~PCI_EXP_LNKCTL_CCC;
+ pcie_capability_write_word(parent, PCI_EXP_LNKCTL, reg16);
+
+ /* Retrain link */
+ reg16 |= PCI_EXP_LNKCTL_RL;
+ pcie_capability_write_word(parent, PCI_EXP_LNKCTL, reg16);
+
+ /* Wait for link training end. Break out after waiting for timeout */
+ start_jiffies = jiffies;
+ for (;;) {
+ pcie_capability_read_word(parent, PCI_EXP_LNKSTA, ®16);
+ 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 */
+ pci_err(parent, "ASPM: Could not configure common clock\n");
+ list_for_each_entry(child, &linkbus->devices, bus_list)
+ pcie_capability_write_word(child, PCI_EXP_LNKCTL,
+ child_reg[PCI_FUNC(child->devfn)]);
+ pcie_capability_write_word(parent, 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);
+}
+
+/* Convert L1SS T_pwr encoding to usec */
+static u32 calc_l1ss_pwron(struct pci_dev *pdev, u32 scale, u32 val)
+{
+ switch (scale) {
+ case 0:
+ return val * 2;
+ case 1:
+ return val * 10;
+ case 2:
+ return val * 100;
+ }
+ pci_err(pdev, "%s: Invalid T_PwrOn scale: %u\n", __func__, scale);
+ return 0;
+}
+
+static void encode_l12_threshold(u32 threshold_us, u32 *scale, u32 *value)
+{
+ u32 threshold_ns = threshold_us * 1000;
+
+ /* See PCIe r3.1, sec 7.33.3 and sec 6.18 */
+ if (threshold_ns < 32) {
+ *scale = 0;
+ *value = threshold_ns;
+ } else if (threshold_ns < 1024) {
+ *scale = 1;
+ *value = threshold_ns >> 5;
+ } else if (threshold_ns < 32768) {
+ *scale = 2;
+ *value = threshold_ns >> 10;
+ } else if (threshold_ns < 1048576) {
+ *scale = 3;
+ *value = threshold_ns >> 15;
+ } else if (threshold_ns < 33554432) {
+ *scale = 4;
+ *value = threshold_ns >> 20;
+ } else {
+ *scale = 5;
+ *value = threshold_ns >> 25;
+ }
+}
+
+struct aspm_register_info {
+ u32 support:2;
+ u32 enabled:2;
+ u32 latency_encoding_l0s;
+ u32 latency_encoding_l1;
+
+ /* L1 substates */
+ u32 l1ss_cap_ptr;
+ u32 l1ss_cap;
+ u32 l1ss_ctl1;
+ u32 l1ss_ctl2;
+};
+
+static void pcie_get_aspm_reg(struct pci_dev *pdev,
+ struct aspm_register_info *info)
+{
+ u16 reg16;
+ u32 reg32;
+
+ pcie_capability_read_dword(pdev, PCI_EXP_LNKCAP, ®32);
+ 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;
+ pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, ®16);
+ info->enabled = reg16 & PCI_EXP_LNKCTL_ASPMC;
+
+ /* Read L1 PM substate capabilities */
+ info->l1ss_cap = info->l1ss_ctl1 = info->l1ss_ctl2 = 0;
+ info->l1ss_cap_ptr = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_L1SS);
+ if (!info->l1ss_cap_ptr)
+ return;
+ pci_read_config_dword(pdev, info->l1ss_cap_ptr + PCI_L1SS_CAP,
+ &info->l1ss_cap);
+ if (!(info->l1ss_cap & PCI_L1SS_CAP_L1_PM_SS)) {
+ info->l1ss_cap = 0;
+ return;
+ }
+
+ /*
+ * If we don't have LTR for the entire path from the Root Complex
+ * to this device, we can't use ASPM L1.2 because it relies on the
+ * LTR_L1.2_THRESHOLD. See PCIe r4.0, secs 5.5.4, 6.18.
+ */
+ if (!pdev->ltr_path)
+ info->l1ss_cap &= ~PCI_L1SS_CAP_ASPM_L1_2;
+
+ pci_read_config_dword(pdev, info->l1ss_cap_ptr + PCI_L1SS_CTL1,
+ &info->l1ss_ctl1);
+ pci_read_config_dword(pdev, info->l1ss_cap_ptr + PCI_L1SS_CTL2,
+ &info->l1ss_ctl2);
+}
+
+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.
+ *
+ * The exit latencies for L1 substates are not advertised
+ * by a device. Since the spec also doesn't mention a way
+ * to determine max latencies introduced by enabling L1
+ * substates on the components, it is not clear how to do
+ * a L1 substate exit latency check. We assume that the
+ * L1 exit latencies advertised by a device include L1
+ * substate latencies (and hence do not do any check).
+ */
+ 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;
+ }
+}
+
+/*
+ * The L1 PM substate capability is only implemented in function 0 in a
+ * multi function device.
+ */
+static struct pci_dev *pci_function_0(struct pci_bus *linkbus)
+{
+ struct pci_dev *child;
+
+ list_for_each_entry(child, &linkbus->devices, bus_list)
+ if (PCI_FUNC(child->devfn) == 0)
+ return child;
+ return NULL;
+}
+
+/* Calculate L1.2 PM substate timing parameters */
+static void aspm_calc_l1ss_info(struct pcie_link_state *link,
+ struct aspm_register_info *upreg,
+ struct aspm_register_info *dwreg)
+{
+ u32 val1, val2, scale1, scale2;
+ u32 t_common_mode, t_power_on, l1_2_threshold, scale, value;
+
+ link->l1ss.up_cap_ptr = upreg->l1ss_cap_ptr;
+ link->l1ss.dw_cap_ptr = dwreg->l1ss_cap_ptr;
+ link->l1ss.ctl1 = link->l1ss.ctl2 = 0;
+
+ if (!(link->aspm_support & ASPM_STATE_L1_2_MASK))
+ return;
+
+ /* Choose the greater of the two Port Common_Mode_Restore_Times */
+ val1 = (upreg->l1ss_cap & PCI_L1SS_CAP_CM_RESTORE_TIME) >> 8;
+ val2 = (dwreg->l1ss_cap & PCI_L1SS_CAP_CM_RESTORE_TIME) >> 8;
+ t_common_mode = max(val1, val2);
+
+ /* Choose the greater of the two Port T_POWER_ON times */
+ val1 = (upreg->l1ss_cap & PCI_L1SS_CAP_P_PWR_ON_VALUE) >> 19;
+ scale1 = (upreg->l1ss_cap & PCI_L1SS_CAP_P_PWR_ON_SCALE) >> 16;
+ val2 = (dwreg->l1ss_cap & PCI_L1SS_CAP_P_PWR_ON_VALUE) >> 19;
+ scale2 = (dwreg->l1ss_cap & PCI_L1SS_CAP_P_PWR_ON_SCALE) >> 16;
+
+ if (calc_l1ss_pwron(link->pdev, scale1, val1) >
+ calc_l1ss_pwron(link->downstream, scale2, val2)) {
+ link->l1ss.ctl2 |= scale1 | (val1 << 3);
+ t_power_on = calc_l1ss_pwron(link->pdev, scale1, val1);
+ } else {
+ link->l1ss.ctl2 |= scale2 | (val2 << 3);
+ t_power_on = calc_l1ss_pwron(link->downstream, scale2, val2);
+ }
+
+ /*
+ * Set LTR_L1.2_THRESHOLD to the time required to transition the
+ * Link from L0 to L1.2 and back to L0 so we enter L1.2 only if
+ * downstream devices report (via LTR) that they can tolerate at
+ * least that much latency.
+ *
+ * Based on PCIe r3.1, sec 5.5.3.3.1, Figures 5-16 and 5-17, and
+ * Table 5-11. T(POWER_OFF) is at most 2us and T(L1.2) is at
+ * least 4us.
+ */
+ l1_2_threshold = 2 + 4 + t_common_mode + t_power_on;
+ encode_l12_threshold(l1_2_threshold, &scale, &value);
+ link->l1ss.ctl1 |= t_common_mode << 8 | scale << 29 | value << 16;
+}
+
+static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
+{
+ struct pci_dev *child = link->downstream, *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;
+ }
+
+ /* Get upstream/downstream components' register state */
+ pcie_get_aspm_reg(parent, &upreg);
+ pcie_get_aspm_reg(child, &dwreg);
+
+ /*
+ * If ASPM not supported, don't mess with the clocks and link,
+ * bail out now.
+ */
+ if (!(upreg.support & dwreg.support))
+ return;
+
+ /* Configure common clock before checking latencies */
+ pcie_aspm_configure_common_clock(link);
+
+ /*
+ * Re-read upstream/downstream components' register state
+ * after clock configuration
+ */
+ pcie_get_aspm_reg(parent, &upreg);
+ 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);
+
+ /* Setup L1 substate */
+ if (upreg.l1ss_cap & dwreg.l1ss_cap & PCI_L1SS_CAP_ASPM_L1_1)
+ link->aspm_support |= ASPM_STATE_L1_1;
+ if (upreg.l1ss_cap & dwreg.l1ss_cap & PCI_L1SS_CAP_ASPM_L1_2)
+ link->aspm_support |= ASPM_STATE_L1_2;
+ if (upreg.l1ss_cap & dwreg.l1ss_cap & PCI_L1SS_CAP_PCIPM_L1_1)
+ link->aspm_support |= ASPM_STATE_L1_1_PCIPM;
+ if (upreg.l1ss_cap & dwreg.l1ss_cap & PCI_L1SS_CAP_PCIPM_L1_2)
+ link->aspm_support |= ASPM_STATE_L1_2_PCIPM;
+
+ if (upreg.l1ss_ctl1 & dwreg.l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_1)
+ link->aspm_enabled |= ASPM_STATE_L1_1;
+ if (upreg.l1ss_ctl1 & dwreg.l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_2)
+ link->aspm_enabled |= ASPM_STATE_L1_2;
+ if (upreg.l1ss_ctl1 & dwreg.l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_1)
+ link->aspm_enabled |= ASPM_STATE_L1_1_PCIPM;
+ if (upreg.l1ss_ctl1 & dwreg.l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_2)
+ link->aspm_enabled |= ASPM_STATE_L1_2_PCIPM;
+
+ if (link->aspm_support & ASPM_STATE_L1SS)
+ aspm_calc_l1ss_info(link, &upreg, &dwreg);
+
+ /* 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 (pci_pcie_type(child) == 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) {
+ u32 reg32, encoding;
+ struct aspm_latency *acceptable =
+ &link->acceptable[PCI_FUNC(child->devfn)];
+
+ if (pci_pcie_type(child) != PCI_EXP_TYPE_ENDPOINT &&
+ pci_pcie_type(child) != PCI_EXP_TYPE_LEG_END)
+ continue;
+
+ pcie_capability_read_dword(child, PCI_EXP_DEVCAP, ®32);
+ /* 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 pci_clear_and_set_dword(struct pci_dev *pdev, int pos,
+ u32 clear, u32 set)
+{
+ u32 val;
+
+ pci_read_config_dword(pdev, pos, &val);
+ val &= ~clear;
+ val |= set;
+ pci_write_config_dword(pdev, pos, val);
+}
+
+/* Configure the ASPM L1 substates */
+static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state)
+{
+ u32 val, enable_req;
+ struct pci_dev *child = link->downstream, *parent = link->pdev;
+ u32 up_cap_ptr = link->l1ss.up_cap_ptr;
+ u32 dw_cap_ptr = link->l1ss.dw_cap_ptr;
+
+ enable_req = (link->aspm_enabled ^ state) & state;
+
+ /*
+ * Here are the rules specified in the PCIe spec for enabling L1SS:
+ * - When enabling L1.x, enable bit at parent first, then at child
+ * - When disabling L1.x, disable bit at child first, then at parent
+ * - When enabling ASPM L1.x, need to disable L1
+ * (at child followed by parent).
+ * - The ASPM/PCIPM L1.2 must be disabled while programming timing
+ * parameters
+ *
+ * To keep it simple, disable all L1SS bits first, and later enable
+ * what is needed.
+ */
+
+ /* Disable all L1 substates */
+ pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1,
+ PCI_L1SS_CTL1_L1SS_MASK, 0);
+ pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1,
+ PCI_L1SS_CTL1_L1SS_MASK, 0);
+ /*
+ * If needed, disable L1, and it gets enabled later
+ * in pcie_config_aspm_link().
+ */
+ if (enable_req & (ASPM_STATE_L1_1 | ASPM_STATE_L1_2)) {
+ pcie_capability_clear_and_set_word(child, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_ASPM_L1, 0);
+ pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_ASPM_L1, 0);
+ }
+
+ if (enable_req & ASPM_STATE_L1_2_MASK) {
+
+ /* Program T_POWER_ON times in both ports */
+ pci_write_config_dword(parent, up_cap_ptr + PCI_L1SS_CTL2,
+ link->l1ss.ctl2);
+ pci_write_config_dword(child, dw_cap_ptr + PCI_L1SS_CTL2,
+ link->l1ss.ctl2);
+
+ /* Program Common_Mode_Restore_Time in upstream device */
+ pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1,
+ PCI_L1SS_CTL1_CM_RESTORE_TIME,
+ link->l1ss.ctl1);
+
+ /* Program LTR_L1.2_THRESHOLD time in both ports */
+ pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1,
+ PCI_L1SS_CTL1_LTR_L12_TH_VALUE |
+ PCI_L1SS_CTL1_LTR_L12_TH_SCALE,
+ link->l1ss.ctl1);
+ pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1,
+ PCI_L1SS_CTL1_LTR_L12_TH_VALUE |
+ PCI_L1SS_CTL1_LTR_L12_TH_SCALE,
+ link->l1ss.ctl1);
+ }
+
+ val = 0;
+ if (state & ASPM_STATE_L1_1)
+ val |= PCI_L1SS_CTL1_ASPM_L1_1;
+ if (state & ASPM_STATE_L1_2)
+ val |= PCI_L1SS_CTL1_ASPM_L1_2;
+ if (state & ASPM_STATE_L1_1_PCIPM)
+ val |= PCI_L1SS_CTL1_PCIPM_L1_1;
+ if (state & ASPM_STATE_L1_2_PCIPM)
+ val |= PCI_L1SS_CTL1_PCIPM_L1_2;
+
+ /* Enable what we need to enable */
+ pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1,
+ PCI_L1SS_CAP_L1_PM_SS, val);
+ pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1,
+ PCI_L1SS_CAP_L1_PM_SS, val);
+}
+
+static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
+{
+ pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_ASPMC, val);
+}
+
+static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
+{
+ u32 upstream = 0, dwstream = 0;
+ struct pci_dev *child = link->downstream, *parent = link->pdev;
+ struct pci_bus *linkbus = parent->subordinate;
+
+ /* Enable only the states that were not explicitly disabled */
+ state &= (link->aspm_capable & ~link->aspm_disable);
+
+ /* Can't enable any substates if L1 is not enabled */
+ if (!(state & ASPM_STATE_L1))
+ state &= ~ASPM_STATE_L1SS;
+
+ /* Spec says both ports must be in D0 before enabling PCI PM substates*/
+ if (parent->current_state != PCI_D0 || child->current_state != PCI_D0) {
+ state &= ~ASPM_STATE_L1_SS_PCIPM;
+ state |= (link->aspm_enabled & ASPM_STATE_L1_SS_PCIPM);
+ }
+
+ /* Nothing to do if the link is already in the requested state */
+ if (link->aspm_enabled == state)
+ return;
+ /* Convert ASPM state to upstream/downstream ASPM register state */
+ if (state & ASPM_STATE_L0S_UP)
+ dwstream |= PCI_EXP_LNKCTL_ASPM_L0S;
+ if (state & ASPM_STATE_L0S_DW)
+ upstream |= PCI_EXP_LNKCTL_ASPM_L0S;
+ if (state & ASPM_STATE_L1) {
+ upstream |= PCI_EXP_LNKCTL_ASPM_L1;
+ dwstream |= PCI_EXP_LNKCTL_ASPM_L1;
+ }
+
+ if (link->aspm_capable & ASPM_STATE_L1SS)
+ pcie_config_aspm_l1ss(link, state);
+
+ /*
+ * 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;
+ 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, &pdev->subordinate->devices, bus_list) {
+ if (!pci_is_pcie(child))
+ return -EINVAL;
+
+ /*
+ * If ASPM is disabled then we're not going to change
+ * the BIOS state. It's safe to continue even if it's a
+ * pre-1.1 device
+ */
+
+ if (aspm_disabled)
+ continue;
+
+ /*
+ * 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
+ */
+ pcie_capability_read_dword(child, PCI_EXP_DEVCAP, ®32);
+ if (!(reg32 & PCI_EXP_DEVCAP_RBER) && !aspm_force) {
+ pci_info(child, "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;
+ link->downstream = pci_function_0(pdev->subordinate);
+
+ /*
+ * Root Ports and PCI/PCI-X to PCIe Bridges are roots of PCIe
+ * hierarchies. Note that some PCIe host implementations omit
+ * the root ports entirely, in which case a downstream port on
+ * a switch may become the root of the link state chain for all
+ * its subordinate endpoints.
+ */
+ if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT ||
+ pci_pcie_type(pdev) == PCI_EXP_TYPE_PCIE_BRIDGE ||
+ !pdev->bus->parent->self) {
+ link->root = link;
+ } else {
+ struct pcie_link_state *parent;
+
+ parent = pdev->bus->parent->self->link_state;
+ if (!parent) {
+ kfree(link);
+ return NULL;
+ }
+
+ link->parent = parent;
+ link->root = link->parent->root;
+ list_add(&link->link, &parent->children);
+ }
+
+ 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 scanned.
+ * @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 (!aspm_support_enabled)
+ return;
+
+ if (pdev->link_state)
+ return;
+
+ /*
+ * We allocate pcie_link_state for the component on the upstream
+ * end of a Link, so there's nothing to do unless this device has a
+ * Link on its secondary side.
+ */
+ if (!pdev->has_secondary_link)
+ return;
+
+ /* VIA has a strange chipset, root port is under a bridge */
+ if (pci_pcie_type(pdev) == 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 &&
+ aspm_policy != POLICY_POWER_SUPERSAVE) {
+ 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 ((pci_pcie_type(child) != PCI_EXP_TYPE_ENDPOINT) &&
+ (pci_pcie_type(child) != 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 (!parent || !parent->link_state)
+ 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_empty(&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 || !link)
+ 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 || !link)
+ return;
+
+ if (aspm_policy != POLICY_POWERSAVE &&
+ aspm_policy != POLICY_POWER_SUPERSAVE)
+ 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);
+}
+
+static void __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem)
+{
+ struct pci_dev *parent = pdev->bus->self;
+ struct pcie_link_state *link;
+
+ if (!pci_is_pcie(pdev))
+ return;
+
+ if (pdev->has_secondary_link)
+ parent = pdev;
+ if (!parent || !parent->link_state)
+ return;
+
+ /*
+ * A driver requested that ASPM be disabled on this device, but
+ * if we don't have permission to manage ASPM (e.g., on ACPI
+ * systems we have to observe the FADT ACPI_FADT_NO_ASPM bit and
+ * the _OSC method), we can't honor that request. Windows has
+ * a similar mechanism using "PciASPMOptOut", which is also
+ * ignored in this situation.
+ */
+ if (aspm_disabled) {
+ pci_warn(pdev, "can't disable ASPM; OS doesn't have ASPM control\n");
+ return;
+ }
+
+ if (sem)
+ 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);
+ if (sem)
+ up_read(&pci_bus_sem);
+}
+
+void pci_disable_link_state_locked(struct pci_dev *pdev, int state)
+{
+ __pci_disable_link_state(pdev, state, false);
+}
+EXPORT_SYMBOL(pci_disable_link_state_locked);
+
+/**
+ * pci_disable_link_state - Disable device's link state, so the link will
+ * never enter specific states. Note that if the BIOS didn't grant ASPM
+ * control to the OS, this does nothing because we can't touch the LNKCTL
+ * register.
+ *
+ * @pdev: PCI device
+ * @state: ASPM link state to disable
+ */
+void pci_disable_link_state(struct pci_dev *pdev, int state)
+{
+ __pci_disable_link_state(pdev, state, true);
+}
+EXPORT_SYMBOL(pci_disable_link_state);
+
+static int pcie_aspm_set_policy(const char *val,
+ const struct kernel_param *kp)
+{
+ int i;
+ struct pcie_link_state *link;
+
+ if (aspm_disabled)
+ return -EPERM;
+ i = sysfs_match_string(policy_str, val);
+ if (i < 0)
+ return i;
+ 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, const 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 state;
+
+ if (aspm_disabled)
+ return -EPERM;
+
+ if (kstrtouint(buf, 10, &state))
+ return -EINVAL;
+ if ((state & ~ASPM_STATE_ALL) != 0)
+ return -EINVAL;
+
+ 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);
+ bool state;
+
+ if (strtobool(buf, &state))
+ return -EINVAL;
+
+ 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_RW(link_state);
+static DEVICE_ATTR_RW(clk_ctl);
+
+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 (!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 (!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_policy = POLICY_DEFAULT;
+ 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 forcibly enabled\n");
+ }
+ return 1;
+}
+
+__setup("pcie_aspm=", pcie_aspm_disable);
+
+void pcie_no_aspm(void)
+{
+ /*
+ * Disabling ASPM is intended to prevent the kernel from modifying
+ * existing hardware state, not to clear existing state. To that end:
+ * (a) set policy to POLICY_DEFAULT in order to avoid changing state
+ * (b) prevent userspace from changing policy
+ */
+ if (!aspm_force) {
+ aspm_policy = POLICY_DEFAULT;
+ aspm_disabled = 1;
+ }
+}
+
+bool pcie_aspm_support_enabled(void)
+{
+ return aspm_support_enabled;
+}
+EXPORT_SYMBOL(pcie_aspm_support_enabled);