1 // SPDX-License-Identifier: GPL-2.0
3 * Enable PCIe link L0s/L1 state and Clock Power Management
5 * Copyright (C) 2007 Intel
6 * Copyright (C) Zhang Yanmin (yanmin.zhang@intel.com)
7 * Copyright (C) Shaohua Li (shaohua.li@intel.com)
10 #include <linux/bitfield.h>
11 #include <linux/kernel.h>
12 #include <linux/limits.h>
13 #include <linux/math.h>
14 #include <linux/module.h>
15 #include <linux/moduleparam.h>
16 #include <linux/pci.h>
17 #include <linux/pci_regs.h>
18 #include <linux/errno.h>
20 #include <linux/init.h>
21 #include <linux/printk.h>
22 #include <linux/slab.h>
23 #include <linux/time.h>
27 #ifdef MODULE_PARAM_PREFIX
28 #undef MODULE_PARAM_PREFIX
30 #define MODULE_PARAM_PREFIX "pcie_aspm."
32 /* Note: those are not register definitions */
33 #define ASPM_STATE_L0S_UP (1) /* Upstream direction L0s state */
34 #define ASPM_STATE_L0S_DW (2) /* Downstream direction L0s state */
35 #define ASPM_STATE_L1 (4) /* L1 state */
36 #define ASPM_STATE_L1_1 (8) /* ASPM L1.1 state */
37 #define ASPM_STATE_L1_2 (0x10) /* ASPM L1.2 state */
38 #define ASPM_STATE_L1_1_PCIPM (0x20) /* PCI PM L1.1 state */
39 #define ASPM_STATE_L1_2_PCIPM (0x40) /* PCI PM L1.2 state */
40 #define ASPM_STATE_L1_SS_PCIPM (ASPM_STATE_L1_1_PCIPM | ASPM_STATE_L1_2_PCIPM)
41 #define ASPM_STATE_L1_2_MASK (ASPM_STATE_L1_2 | ASPM_STATE_L1_2_PCIPM)
42 #define ASPM_STATE_L1SS (ASPM_STATE_L1_1 | ASPM_STATE_L1_1_PCIPM |\
44 #define ASPM_STATE_L0S (ASPM_STATE_L0S_UP | ASPM_STATE_L0S_DW)
45 #define ASPM_STATE_ALL (ASPM_STATE_L0S | ASPM_STATE_L1 | \
48 struct pcie_link_state {
49 struct pci_dev *pdev; /* Upstream component of the Link */
50 struct pci_dev *downstream; /* Downstream component, function 0 */
51 struct pcie_link_state *root; /* pointer to the root port link */
52 struct pcie_link_state *parent; /* pointer to the parent Link state */
53 struct list_head sibling; /* node in link_list */
56 u32 aspm_support:7; /* Supported ASPM state */
57 u32 aspm_enabled:7; /* Enabled ASPM state */
58 u32 aspm_capable:7; /* Capable ASPM state with latency */
59 u32 aspm_default:7; /* Default ASPM state by BIOS */
60 u32 aspm_disable:7; /* Disabled ASPM state */
63 u32 clkpm_capable:1; /* Clock PM capable? */
64 u32 clkpm_enabled:1; /* Current Clock PM state */
65 u32 clkpm_default:1; /* Default Clock PM state by BIOS */
66 u32 clkpm_disable:1; /* Clock PM disabled */
69 static int aspm_disabled, aspm_force;
70 static bool aspm_support_enabled = true;
71 static DEFINE_MUTEX(aspm_lock);
72 static LIST_HEAD(link_list);
74 #define POLICY_DEFAULT 0 /* BIOS default setting */
75 #define POLICY_PERFORMANCE 1 /* high performance */
76 #define POLICY_POWERSAVE 2 /* high power saving */
77 #define POLICY_POWER_SUPERSAVE 3 /* possibly even more power saving */
79 #ifdef CONFIG_PCIEASPM_PERFORMANCE
80 static int aspm_policy = POLICY_PERFORMANCE;
81 #elif defined CONFIG_PCIEASPM_POWERSAVE
82 static int aspm_policy = POLICY_POWERSAVE;
83 #elif defined CONFIG_PCIEASPM_POWER_SUPERSAVE
84 static int aspm_policy = POLICY_POWER_SUPERSAVE;
86 static int aspm_policy;
89 static const char *policy_str[] = {
90 [POLICY_DEFAULT] = "default",
91 [POLICY_PERFORMANCE] = "performance",
92 [POLICY_POWERSAVE] = "powersave",
93 [POLICY_POWER_SUPERSAVE] = "powersupersave"
97 * The L1 PM substate capability is only implemented in function 0 in a
98 * multi function device.
100 static struct pci_dev *pci_function_0(struct pci_bus *linkbus)
102 struct pci_dev *child;
104 list_for_each_entry(child, &linkbus->devices, bus_list)
105 if (PCI_FUNC(child->devfn) == 0)
110 static int policy_to_aspm_state(struct pcie_link_state *link)
112 switch (aspm_policy) {
113 case POLICY_PERFORMANCE:
114 /* Disable ASPM and Clock PM */
116 case POLICY_POWERSAVE:
117 /* Enable ASPM L0s/L1 */
118 return (ASPM_STATE_L0S | ASPM_STATE_L1);
119 case POLICY_POWER_SUPERSAVE:
120 /* Enable Everything */
121 return ASPM_STATE_ALL;
123 return link->aspm_default;
128 static int policy_to_clkpm_state(struct pcie_link_state *link)
130 switch (aspm_policy) {
131 case POLICY_PERFORMANCE:
132 /* Disable ASPM and Clock PM */
134 case POLICY_POWERSAVE:
135 case POLICY_POWER_SUPERSAVE:
136 /* Enable Clock PM */
139 return link->clkpm_default;
144 static void pcie_set_clkpm_nocheck(struct pcie_link_state *link, int enable)
146 struct pci_dev *child;
147 struct pci_bus *linkbus = link->pdev->subordinate;
148 u32 val = enable ? PCI_EXP_LNKCTL_CLKREQ_EN : 0;
150 list_for_each_entry(child, &linkbus->devices, bus_list)
151 pcie_capability_clear_and_set_word(child, PCI_EXP_LNKCTL,
152 PCI_EXP_LNKCTL_CLKREQ_EN,
154 link->clkpm_enabled = !!enable;
157 static void pcie_set_clkpm(struct pcie_link_state *link, int enable)
160 * Don't enable Clock PM if the link is not Clock PM capable
161 * or Clock PM is disabled
163 if (!link->clkpm_capable || link->clkpm_disable)
165 /* Need nothing if the specified equals to current state */
166 if (link->clkpm_enabled == enable)
168 pcie_set_clkpm_nocheck(link, enable);
171 static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
173 int capable = 1, enabled = 1;
176 struct pci_dev *child;
177 struct pci_bus *linkbus = link->pdev->subordinate;
179 /* All functions should have the same cap and state, take the worst */
180 list_for_each_entry(child, &linkbus->devices, bus_list) {
181 pcie_capability_read_dword(child, PCI_EXP_LNKCAP, ®32);
182 if (!(reg32 & PCI_EXP_LNKCAP_CLKPM)) {
187 pcie_capability_read_word(child, PCI_EXP_LNKCTL, ®16);
188 if (!(reg16 & PCI_EXP_LNKCTL_CLKREQ_EN))
191 link->clkpm_enabled = enabled;
192 link->clkpm_default = enabled;
193 link->clkpm_capable = capable;
194 link->clkpm_disable = blacklist ? 1 : 0;
198 * pcie_aspm_configure_common_clock: check if the 2 ends of a link
199 * could use common clock. If they are, configure them to use the
200 * common clock. That will reduce the ASPM state exit latency.
202 static void pcie_aspm_configure_common_clock(struct pcie_link_state *link)
205 u16 reg16, ccc, parent_old_ccc, child_old_ccc[8];
206 struct pci_dev *child, *parent = link->pdev;
207 struct pci_bus *linkbus = parent->subordinate;
209 * All functions of a slot should have the same Slot Clock
210 * Configuration, so just check one function
212 child = list_entry(linkbus->devices.next, struct pci_dev, bus_list);
213 BUG_ON(!pci_is_pcie(child));
215 /* Check downstream component if bit Slot Clock Configuration is 1 */
216 pcie_capability_read_word(child, PCI_EXP_LNKSTA, ®16);
217 if (!(reg16 & PCI_EXP_LNKSTA_SLC))
220 /* Check upstream component if bit Slot Clock Configuration is 1 */
221 pcie_capability_read_word(parent, PCI_EXP_LNKSTA, ®16);
222 if (!(reg16 & PCI_EXP_LNKSTA_SLC))
225 /* Port might be already in common clock mode */
226 pcie_capability_read_word(parent, PCI_EXP_LNKCTL, ®16);
227 parent_old_ccc = reg16 & PCI_EXP_LNKCTL_CCC;
228 if (same_clock && (reg16 & PCI_EXP_LNKCTL_CCC)) {
229 bool consistent = true;
231 list_for_each_entry(child, &linkbus->devices, bus_list) {
232 pcie_capability_read_word(child, PCI_EXP_LNKCTL,
234 if (!(reg16 & PCI_EXP_LNKCTL_CCC)) {
241 pci_info(parent, "ASPM: current common clock configuration is inconsistent, reconfiguring\n");
244 ccc = same_clock ? PCI_EXP_LNKCTL_CCC : 0;
245 /* Configure downstream component, all functions */
246 list_for_each_entry(child, &linkbus->devices, bus_list) {
247 pcie_capability_read_word(child, PCI_EXP_LNKCTL, ®16);
248 child_old_ccc[PCI_FUNC(child->devfn)] = reg16 & PCI_EXP_LNKCTL_CCC;
249 pcie_capability_clear_and_set_word(child, PCI_EXP_LNKCTL,
250 PCI_EXP_LNKCTL_CCC, ccc);
253 /* Configure upstream component */
254 pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL,
255 PCI_EXP_LNKCTL_CCC, ccc);
257 if (pcie_retrain_link(link->pdev, true)) {
259 /* Training failed. Restore common clock configurations */
260 pci_err(parent, "ASPM: Could not configure common clock\n");
261 list_for_each_entry(child, &linkbus->devices, bus_list)
262 pcie_capability_clear_and_set_word(child, PCI_EXP_LNKCTL,
264 child_old_ccc[PCI_FUNC(child->devfn)]);
265 pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL,
266 PCI_EXP_LNKCTL_CCC, parent_old_ccc);
270 /* Convert L0s latency encoding to ns */
271 static u32 calc_l0s_latency(u32 lnkcap)
273 u32 encoding = FIELD_GET(PCI_EXP_LNKCAP_L0SEL, lnkcap);
276 return 5 * NSEC_PER_USEC; /* > 4us */
277 return (64 << encoding);
280 /* Convert L0s acceptable latency encoding to ns */
281 static u32 calc_l0s_acceptable(u32 encoding)
285 return (64 << encoding);
288 /* Convert L1 latency encoding to ns */
289 static u32 calc_l1_latency(u32 lnkcap)
291 u32 encoding = FIELD_GET(PCI_EXP_LNKCAP_L1EL, lnkcap);
294 return 65 * NSEC_PER_USEC; /* > 64us */
295 return NSEC_PER_USEC << encoding;
298 /* Convert L1 acceptable latency encoding to ns */
299 static u32 calc_l1_acceptable(u32 encoding)
303 return NSEC_PER_USEC << encoding;
306 /* Convert L1SS T_pwr encoding to usec */
307 static u32 calc_l12_pwron(struct pci_dev *pdev, u32 scale, u32 val)
317 pci_err(pdev, "%s: Invalid T_PwrOn scale: %u\n", __func__, scale);
322 * Encode an LTR_L1.2_THRESHOLD value for the L1 PM Substates Control 1
323 * register. Ports enter L1.2 when the most recent LTR value is greater
324 * than or equal to LTR_L1.2_THRESHOLD, so we round up to make sure we
325 * don't enter L1.2 too aggressively.
327 * See PCIe r6.0, sec 5.5.1, 6.18, 7.8.3.3.
329 static void encode_l12_threshold(u32 threshold_us, u32 *scale, u32 *value)
331 u64 threshold_ns = (u64)threshold_us * NSEC_PER_USEC;
334 * LTR_L1.2_THRESHOLD_Value ("value") is a 10-bit field with max
337 if (threshold_ns <= 1 * FIELD_MAX(PCI_L1SS_CTL1_LTR_L12_TH_VALUE)) {
338 *scale = 0; /* Value times 1ns */
339 *value = threshold_ns;
340 } else if (threshold_ns <= 32 * FIELD_MAX(PCI_L1SS_CTL1_LTR_L12_TH_VALUE)) {
341 *scale = 1; /* Value times 32ns */
342 *value = roundup(threshold_ns, 32) / 32;
343 } else if (threshold_ns <= 1024 * FIELD_MAX(PCI_L1SS_CTL1_LTR_L12_TH_VALUE)) {
344 *scale = 2; /* Value times 1024ns */
345 *value = roundup(threshold_ns, 1024) / 1024;
346 } else if (threshold_ns <= 32768 * FIELD_MAX(PCI_L1SS_CTL1_LTR_L12_TH_VALUE)) {
347 *scale = 3; /* Value times 32768ns */
348 *value = roundup(threshold_ns, 32768) / 32768;
349 } else if (threshold_ns <= 1048576 * FIELD_MAX(PCI_L1SS_CTL1_LTR_L12_TH_VALUE)) {
350 *scale = 4; /* Value times 1048576ns */
351 *value = roundup(threshold_ns, 1048576) / 1048576;
352 } else if (threshold_ns <= (u64)33554432 * FIELD_MAX(PCI_L1SS_CTL1_LTR_L12_TH_VALUE)) {
353 *scale = 5; /* Value times 33554432ns */
354 *value = roundup(threshold_ns, 33554432) / 33554432;
357 *value = FIELD_MAX(PCI_L1SS_CTL1_LTR_L12_TH_VALUE);
361 static void pcie_aspm_check_latency(struct pci_dev *endpoint)
363 u32 latency, encoding, lnkcap_up, lnkcap_dw;
364 u32 l1_switch_latency = 0, latency_up_l0s;
365 u32 latency_up_l1, latency_dw_l0s, latency_dw_l1;
366 u32 acceptable_l0s, acceptable_l1;
367 struct pcie_link_state *link;
369 /* Device not in D0 doesn't need latency check */
370 if ((endpoint->current_state != PCI_D0) &&
371 (endpoint->current_state != PCI_UNKNOWN))
374 link = endpoint->bus->self->link_state;
376 /* Calculate endpoint L0s acceptable latency */
377 encoding = FIELD_GET(PCI_EXP_DEVCAP_L0S, endpoint->devcap);
378 acceptable_l0s = calc_l0s_acceptable(encoding);
380 /* Calculate endpoint L1 acceptable latency */
381 encoding = FIELD_GET(PCI_EXP_DEVCAP_L1, endpoint->devcap);
382 acceptable_l1 = calc_l1_acceptable(encoding);
385 struct pci_dev *dev = pci_function_0(link->pdev->subordinate);
387 /* Read direction exit latencies */
388 pcie_capability_read_dword(link->pdev, PCI_EXP_LNKCAP,
390 pcie_capability_read_dword(dev, PCI_EXP_LNKCAP,
392 latency_up_l0s = calc_l0s_latency(lnkcap_up);
393 latency_up_l1 = calc_l1_latency(lnkcap_up);
394 latency_dw_l0s = calc_l0s_latency(lnkcap_dw);
395 latency_dw_l1 = calc_l1_latency(lnkcap_dw);
397 /* Check upstream direction L0s latency */
398 if ((link->aspm_capable & ASPM_STATE_L0S_UP) &&
399 (latency_up_l0s > acceptable_l0s))
400 link->aspm_capable &= ~ASPM_STATE_L0S_UP;
402 /* Check downstream direction L0s latency */
403 if ((link->aspm_capable & ASPM_STATE_L0S_DW) &&
404 (latency_dw_l0s > acceptable_l0s))
405 link->aspm_capable &= ~ASPM_STATE_L0S_DW;
408 * Every switch on the path to root complex need 1
409 * more microsecond for L1. Spec doesn't mention L0s.
411 * The exit latencies for L1 substates are not advertised
412 * by a device. Since the spec also doesn't mention a way
413 * to determine max latencies introduced by enabling L1
414 * substates on the components, it is not clear how to do
415 * a L1 substate exit latency check. We assume that the
416 * L1 exit latencies advertised by a device include L1
417 * substate latencies (and hence do not do any check).
419 latency = max_t(u32, latency_up_l1, latency_dw_l1);
420 if ((link->aspm_capable & ASPM_STATE_L1) &&
421 (latency + l1_switch_latency > acceptable_l1))
422 link->aspm_capable &= ~ASPM_STATE_L1;
423 l1_switch_latency += NSEC_PER_USEC;
429 /* Calculate L1.2 PM substate timing parameters */
430 static void aspm_calc_l12_info(struct pcie_link_state *link,
431 u32 parent_l1ss_cap, u32 child_l1ss_cap)
433 struct pci_dev *child = link->downstream, *parent = link->pdev;
434 u32 val1, val2, scale1, scale2;
435 u32 t_common_mode, t_power_on, l1_2_threshold, scale, value;
436 u32 ctl1 = 0, ctl2 = 0;
437 u32 pctl1, pctl2, cctl1, cctl2;
438 u32 pl1_2_enables, cl1_2_enables;
440 /* Choose the greater of the two Port Common_Mode_Restore_Times */
441 val1 = FIELD_GET(PCI_L1SS_CAP_CM_RESTORE_TIME, parent_l1ss_cap);
442 val2 = FIELD_GET(PCI_L1SS_CAP_CM_RESTORE_TIME, child_l1ss_cap);
443 t_common_mode = max(val1, val2);
445 /* Choose the greater of the two Port T_POWER_ON times */
446 val1 = FIELD_GET(PCI_L1SS_CAP_P_PWR_ON_VALUE, parent_l1ss_cap);
447 scale1 = FIELD_GET(PCI_L1SS_CAP_P_PWR_ON_SCALE, parent_l1ss_cap);
448 val2 = FIELD_GET(PCI_L1SS_CAP_P_PWR_ON_VALUE, child_l1ss_cap);
449 scale2 = FIELD_GET(PCI_L1SS_CAP_P_PWR_ON_SCALE, child_l1ss_cap);
451 if (calc_l12_pwron(parent, scale1, val1) >
452 calc_l12_pwron(child, scale2, val2)) {
453 ctl2 |= FIELD_PREP(PCI_L1SS_CTL2_T_PWR_ON_SCALE, scale1) |
454 FIELD_PREP(PCI_L1SS_CTL2_T_PWR_ON_VALUE, val1);
455 t_power_on = calc_l12_pwron(parent, scale1, val1);
457 ctl2 |= FIELD_PREP(PCI_L1SS_CTL2_T_PWR_ON_SCALE, scale2) |
458 FIELD_PREP(PCI_L1SS_CTL2_T_PWR_ON_VALUE, val2);
459 t_power_on = calc_l12_pwron(child, scale2, val2);
463 * Set LTR_L1.2_THRESHOLD to the time required to transition the
464 * Link from L0 to L1.2 and back to L0 so we enter L1.2 only if
465 * downstream devices report (via LTR) that they can tolerate at
466 * least that much latency.
468 * Based on PCIe r3.1, sec 5.5.3.3.1, Figures 5-16 and 5-17, and
469 * Table 5-11. T(POWER_OFF) is at most 2us and T(L1.2) is at
472 l1_2_threshold = 2 + 4 + t_common_mode + t_power_on;
473 encode_l12_threshold(l1_2_threshold, &scale, &value);
474 ctl1 |= FIELD_PREP(PCI_L1SS_CTL1_CM_RESTORE_TIME, t_common_mode) |
475 FIELD_PREP(PCI_L1SS_CTL1_LTR_L12_TH_VALUE, value) |
476 FIELD_PREP(PCI_L1SS_CTL1_LTR_L12_TH_SCALE, scale);
478 /* Some broken devices only support dword access to L1 SS */
479 pci_read_config_dword(parent, parent->l1ss + PCI_L1SS_CTL1, &pctl1);
480 pci_read_config_dword(parent, parent->l1ss + PCI_L1SS_CTL2, &pctl2);
481 pci_read_config_dword(child, child->l1ss + PCI_L1SS_CTL1, &cctl1);
482 pci_read_config_dword(child, child->l1ss + PCI_L1SS_CTL2, &cctl2);
484 if (ctl1 == pctl1 && ctl1 == cctl1 &&
485 ctl2 == pctl2 && ctl2 == cctl2)
488 /* Disable L1.2 while updating. See PCIe r5.0, sec 5.5.4, 7.8.3.3 */
489 pl1_2_enables = pctl1 & PCI_L1SS_CTL1_L1_2_MASK;
490 cl1_2_enables = cctl1 & PCI_L1SS_CTL1_L1_2_MASK;
492 if (pl1_2_enables || cl1_2_enables) {
493 pci_clear_and_set_config_dword(child,
494 child->l1ss + PCI_L1SS_CTL1,
495 PCI_L1SS_CTL1_L1_2_MASK, 0);
496 pci_clear_and_set_config_dword(parent,
497 parent->l1ss + PCI_L1SS_CTL1,
498 PCI_L1SS_CTL1_L1_2_MASK, 0);
501 /* Program T_POWER_ON times in both ports */
502 pci_write_config_dword(parent, parent->l1ss + PCI_L1SS_CTL2, ctl2);
503 pci_write_config_dword(child, child->l1ss + PCI_L1SS_CTL2, ctl2);
505 /* Program Common_Mode_Restore_Time in upstream device */
506 pci_clear_and_set_config_dword(parent, parent->l1ss + PCI_L1SS_CTL1,
507 PCI_L1SS_CTL1_CM_RESTORE_TIME, ctl1);
509 /* Program LTR_L1.2_THRESHOLD time in both ports */
510 pci_clear_and_set_config_dword(parent, parent->l1ss + PCI_L1SS_CTL1,
511 PCI_L1SS_CTL1_LTR_L12_TH_VALUE |
512 PCI_L1SS_CTL1_LTR_L12_TH_SCALE,
514 pci_clear_and_set_config_dword(child, child->l1ss + PCI_L1SS_CTL1,
515 PCI_L1SS_CTL1_LTR_L12_TH_VALUE |
516 PCI_L1SS_CTL1_LTR_L12_TH_SCALE,
519 if (pl1_2_enables || cl1_2_enables) {
520 pci_clear_and_set_config_dword(parent,
521 parent->l1ss + PCI_L1SS_CTL1, 0,
523 pci_clear_and_set_config_dword(child,
524 child->l1ss + PCI_L1SS_CTL1, 0,
529 static void aspm_l1ss_init(struct pcie_link_state *link)
531 struct pci_dev *child = link->downstream, *parent = link->pdev;
532 u32 parent_l1ss_cap, child_l1ss_cap;
533 u32 parent_l1ss_ctl1 = 0, child_l1ss_ctl1 = 0;
535 if (!parent->l1ss || !child->l1ss)
538 /* Setup L1 substate */
539 pci_read_config_dword(parent, parent->l1ss + PCI_L1SS_CAP,
541 pci_read_config_dword(child, child->l1ss + PCI_L1SS_CAP,
544 if (!(parent_l1ss_cap & PCI_L1SS_CAP_L1_PM_SS))
546 if (!(child_l1ss_cap & PCI_L1SS_CAP_L1_PM_SS))
550 * If we don't have LTR for the entire path from the Root Complex
551 * to this device, we can't use ASPM L1.2 because it relies on the
552 * LTR_L1.2_THRESHOLD. See PCIe r4.0, secs 5.5.4, 6.18.
554 if (!child->ltr_path)
555 child_l1ss_cap &= ~PCI_L1SS_CAP_ASPM_L1_2;
557 if (parent_l1ss_cap & child_l1ss_cap & PCI_L1SS_CAP_ASPM_L1_1)
558 link->aspm_support |= ASPM_STATE_L1_1;
559 if (parent_l1ss_cap & child_l1ss_cap & PCI_L1SS_CAP_ASPM_L1_2)
560 link->aspm_support |= ASPM_STATE_L1_2;
561 if (parent_l1ss_cap & child_l1ss_cap & PCI_L1SS_CAP_PCIPM_L1_1)
562 link->aspm_support |= ASPM_STATE_L1_1_PCIPM;
563 if (parent_l1ss_cap & child_l1ss_cap & PCI_L1SS_CAP_PCIPM_L1_2)
564 link->aspm_support |= ASPM_STATE_L1_2_PCIPM;
567 pci_read_config_dword(parent, parent->l1ss + PCI_L1SS_CTL1,
570 pci_read_config_dword(child, child->l1ss + PCI_L1SS_CTL1,
573 if (parent_l1ss_ctl1 & child_l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_1)
574 link->aspm_enabled |= ASPM_STATE_L1_1;
575 if (parent_l1ss_ctl1 & child_l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_2)
576 link->aspm_enabled |= ASPM_STATE_L1_2;
577 if (parent_l1ss_ctl1 & child_l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_1)
578 link->aspm_enabled |= ASPM_STATE_L1_1_PCIPM;
579 if (parent_l1ss_ctl1 & child_l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_2)
580 link->aspm_enabled |= ASPM_STATE_L1_2_PCIPM;
582 if (link->aspm_support & ASPM_STATE_L1_2_MASK)
583 aspm_calc_l12_info(link, parent_l1ss_cap, child_l1ss_cap);
586 static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
588 struct pci_dev *child = link->downstream, *parent = link->pdev;
589 u32 parent_lnkcap, child_lnkcap;
590 u16 parent_lnkctl, child_lnkctl;
591 struct pci_bus *linkbus = parent->subordinate;
594 /* Set enabled/disable so that we will disable ASPM later */
595 link->aspm_enabled = ASPM_STATE_ALL;
596 link->aspm_disable = ASPM_STATE_ALL;
601 * If ASPM not supported, don't mess with the clocks and link,
604 pcie_capability_read_dword(parent, PCI_EXP_LNKCAP, &parent_lnkcap);
605 pcie_capability_read_dword(child, PCI_EXP_LNKCAP, &child_lnkcap);
606 if (!(parent_lnkcap & child_lnkcap & PCI_EXP_LNKCAP_ASPMS))
609 /* Configure common clock before checking latencies */
610 pcie_aspm_configure_common_clock(link);
613 * Re-read upstream/downstream components' register state after
614 * clock configuration. L0s & L1 exit latencies in the otherwise
615 * read-only Link Capabilities may change depending on common clock
616 * configuration (PCIe r5.0, sec 7.5.3.6).
618 pcie_capability_read_dword(parent, PCI_EXP_LNKCAP, &parent_lnkcap);
619 pcie_capability_read_dword(child, PCI_EXP_LNKCAP, &child_lnkcap);
620 pcie_capability_read_word(parent, PCI_EXP_LNKCTL, &parent_lnkctl);
621 pcie_capability_read_word(child, PCI_EXP_LNKCTL, &child_lnkctl);
626 * Note that we must not enable L0s in either direction on a
627 * given link unless components on both sides of the link each
630 if (parent_lnkcap & child_lnkcap & PCI_EXP_LNKCAP_ASPM_L0S)
631 link->aspm_support |= ASPM_STATE_L0S;
633 if (child_lnkctl & PCI_EXP_LNKCTL_ASPM_L0S)
634 link->aspm_enabled |= ASPM_STATE_L0S_UP;
635 if (parent_lnkctl & PCI_EXP_LNKCTL_ASPM_L0S)
636 link->aspm_enabled |= ASPM_STATE_L0S_DW;
639 if (parent_lnkcap & child_lnkcap & PCI_EXP_LNKCAP_ASPM_L1)
640 link->aspm_support |= ASPM_STATE_L1;
642 if (parent_lnkctl & child_lnkctl & PCI_EXP_LNKCTL_ASPM_L1)
643 link->aspm_enabled |= ASPM_STATE_L1;
645 aspm_l1ss_init(link);
647 /* Save default state */
648 link->aspm_default = link->aspm_enabled;
650 /* Setup initial capable state. Will be updated later */
651 link->aspm_capable = link->aspm_support;
653 /* Get and check endpoint acceptable latencies */
654 list_for_each_entry(child, &linkbus->devices, bus_list) {
655 if (pci_pcie_type(child) != PCI_EXP_TYPE_ENDPOINT &&
656 pci_pcie_type(child) != PCI_EXP_TYPE_LEG_END)
659 pcie_aspm_check_latency(child);
663 /* Configure the ASPM L1 substates */
664 static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state)
667 struct pci_dev *child = link->downstream, *parent = link->pdev;
669 enable_req = (link->aspm_enabled ^ state) & state;
672 * Here are the rules specified in the PCIe spec for enabling L1SS:
673 * - When enabling L1.x, enable bit at parent first, then at child
674 * - When disabling L1.x, disable bit at child first, then at parent
675 * - When enabling ASPM L1.x, need to disable L1
676 * (at child followed by parent).
677 * - The ASPM/PCIPM L1.2 must be disabled while programming timing
680 * To keep it simple, disable all L1SS bits first, and later enable
684 /* Disable all L1 substates */
685 pci_clear_and_set_config_dword(child, child->l1ss + PCI_L1SS_CTL1,
686 PCI_L1SS_CTL1_L1SS_MASK, 0);
687 pci_clear_and_set_config_dword(parent, parent->l1ss + PCI_L1SS_CTL1,
688 PCI_L1SS_CTL1_L1SS_MASK, 0);
690 * If needed, disable L1, and it gets enabled later
691 * in pcie_config_aspm_link().
693 if (enable_req & (ASPM_STATE_L1_1 | ASPM_STATE_L1_2)) {
694 pcie_capability_clear_word(child, PCI_EXP_LNKCTL,
695 PCI_EXP_LNKCTL_ASPM_L1);
696 pcie_capability_clear_word(parent, PCI_EXP_LNKCTL,
697 PCI_EXP_LNKCTL_ASPM_L1);
701 if (state & ASPM_STATE_L1_1)
702 val |= PCI_L1SS_CTL1_ASPM_L1_1;
703 if (state & ASPM_STATE_L1_2)
704 val |= PCI_L1SS_CTL1_ASPM_L1_2;
705 if (state & ASPM_STATE_L1_1_PCIPM)
706 val |= PCI_L1SS_CTL1_PCIPM_L1_1;
707 if (state & ASPM_STATE_L1_2_PCIPM)
708 val |= PCI_L1SS_CTL1_PCIPM_L1_2;
710 /* Enable what we need to enable */
711 pci_clear_and_set_config_dword(parent, parent->l1ss + PCI_L1SS_CTL1,
712 PCI_L1SS_CTL1_L1SS_MASK, val);
713 pci_clear_and_set_config_dword(child, child->l1ss + PCI_L1SS_CTL1,
714 PCI_L1SS_CTL1_L1SS_MASK, val);
717 static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
719 pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL,
720 PCI_EXP_LNKCTL_ASPMC, val);
723 static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
725 u32 upstream = 0, dwstream = 0;
726 struct pci_dev *child = link->downstream, *parent = link->pdev;
727 struct pci_bus *linkbus = parent->subordinate;
729 /* Enable only the states that were not explicitly disabled */
730 state &= (link->aspm_capable & ~link->aspm_disable);
732 /* Can't enable any substates if L1 is not enabled */
733 if (!(state & ASPM_STATE_L1))
734 state &= ~ASPM_STATE_L1SS;
736 /* Spec says both ports must be in D0 before enabling PCI PM substates*/
737 if (parent->current_state != PCI_D0 || child->current_state != PCI_D0) {
738 state &= ~ASPM_STATE_L1_SS_PCIPM;
739 state |= (link->aspm_enabled & ASPM_STATE_L1_SS_PCIPM);
742 /* Nothing to do if the link is already in the requested state */
743 if (link->aspm_enabled == state)
745 /* Convert ASPM state to upstream/downstream ASPM register state */
746 if (state & ASPM_STATE_L0S_UP)
747 dwstream |= PCI_EXP_LNKCTL_ASPM_L0S;
748 if (state & ASPM_STATE_L0S_DW)
749 upstream |= PCI_EXP_LNKCTL_ASPM_L0S;
750 if (state & ASPM_STATE_L1) {
751 upstream |= PCI_EXP_LNKCTL_ASPM_L1;
752 dwstream |= PCI_EXP_LNKCTL_ASPM_L1;
755 if (link->aspm_capable & ASPM_STATE_L1SS)
756 pcie_config_aspm_l1ss(link, state);
759 * Spec 2.0 suggests all functions should be configured the
760 * same setting for ASPM. Enabling ASPM L1 should be done in
761 * upstream component first and then downstream, and vice
762 * versa for disabling ASPM L1. Spec doesn't mention L0S.
764 if (state & ASPM_STATE_L1)
765 pcie_config_aspm_dev(parent, upstream);
766 list_for_each_entry(child, &linkbus->devices, bus_list)
767 pcie_config_aspm_dev(child, dwstream);
768 if (!(state & ASPM_STATE_L1))
769 pcie_config_aspm_dev(parent, upstream);
771 link->aspm_enabled = state;
774 static void pcie_config_aspm_path(struct pcie_link_state *link)
777 pcie_config_aspm_link(link, policy_to_aspm_state(link));
782 static void free_link_state(struct pcie_link_state *link)
784 link->pdev->link_state = NULL;
788 static int pcie_aspm_sanity_check(struct pci_dev *pdev)
790 struct pci_dev *child;
794 * Some functions in a slot might not all be PCIe functions,
795 * very strange. Disable ASPM for the whole slot
797 list_for_each_entry(child, &pdev->subordinate->devices, bus_list) {
798 if (!pci_is_pcie(child))
802 * If ASPM is disabled then we're not going to change
803 * the BIOS state. It's safe to continue even if it's a
811 * Disable ASPM for pre-1.1 PCIe device, we follow MS to use
812 * RBER bit to determine if a function is 1.1 version device
814 pcie_capability_read_dword(child, PCI_EXP_DEVCAP, ®32);
815 if (!(reg32 & PCI_EXP_DEVCAP_RBER) && !aspm_force) {
816 pci_info(child, "disabling ASPM on pre-1.1 PCIe device. You can enable it with 'pcie_aspm=force'\n");
823 static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
825 struct pcie_link_state *link;
827 link = kzalloc(sizeof(*link), GFP_KERNEL);
831 INIT_LIST_HEAD(&link->sibling);
833 link->downstream = pci_function_0(pdev->subordinate);
836 * Root Ports and PCI/PCI-X to PCIe Bridges are roots of PCIe
837 * hierarchies. Note that some PCIe host implementations omit
838 * the root ports entirely, in which case a downstream port on
839 * a switch may become the root of the link state chain for all
840 * its subordinate endpoints.
842 if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT ||
843 pci_pcie_type(pdev) == PCI_EXP_TYPE_PCIE_BRIDGE ||
844 !pdev->bus->parent->self) {
847 struct pcie_link_state *parent;
849 parent = pdev->bus->parent->self->link_state;
855 link->parent = parent;
856 link->root = link->parent->root;
859 list_add(&link->sibling, &link_list);
860 pdev->link_state = link;
864 static void pcie_aspm_update_sysfs_visibility(struct pci_dev *pdev)
866 struct pci_dev *child;
868 list_for_each_entry(child, &pdev->subordinate->devices, bus_list)
869 sysfs_update_group(&child->dev.kobj, &aspm_ctrl_attr_group);
873 * pcie_aspm_init_link_state: Initiate PCI express link state.
874 * It is called after the pcie and its children devices are scanned.
875 * @pdev: the root port or switch downstream port
877 void pcie_aspm_init_link_state(struct pci_dev *pdev)
879 struct pcie_link_state *link;
880 int blacklist = !!pcie_aspm_sanity_check(pdev);
882 if (!aspm_support_enabled)
885 if (pdev->link_state)
889 * We allocate pcie_link_state for the component on the upstream
890 * end of a Link, so there's nothing to do unless this device is
893 if (!pcie_downstream_port(pdev))
896 /* VIA has a strange chipset, root port is under a bridge */
897 if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT &&
901 down_read(&pci_bus_sem);
902 if (list_empty(&pdev->subordinate->devices))
905 mutex_lock(&aspm_lock);
906 link = alloc_pcie_link_state(pdev);
910 * Setup initial ASPM state. Note that we need to configure
911 * upstream links also because capable state of them can be
912 * update through pcie_aspm_cap_init().
914 pcie_aspm_cap_init(link, blacklist);
916 /* Setup initial Clock PM state */
917 pcie_clkpm_cap_init(link, blacklist);
920 * At this stage drivers haven't had an opportunity to change the
921 * link policy setting. Enabling ASPM on broken hardware can cripple
922 * it even before the driver has had a chance to disable ASPM, so
923 * default to a safe level right now. If we're enabling ASPM beyond
924 * the BIOS's expectation, we'll do so once pci_enable_device() is
927 if (aspm_policy != POLICY_POWERSAVE &&
928 aspm_policy != POLICY_POWER_SUPERSAVE) {
929 pcie_config_aspm_path(link);
930 pcie_set_clkpm(link, policy_to_clkpm_state(link));
933 pcie_aspm_update_sysfs_visibility(pdev);
936 mutex_unlock(&aspm_lock);
938 up_read(&pci_bus_sem);
941 /* Recheck latencies and update aspm_capable for links under the root */
942 static void pcie_update_aspm_capable(struct pcie_link_state *root)
944 struct pcie_link_state *link;
945 BUG_ON(root->parent);
946 list_for_each_entry(link, &link_list, sibling) {
947 if (link->root != root)
949 link->aspm_capable = link->aspm_support;
951 list_for_each_entry(link, &link_list, sibling) {
952 struct pci_dev *child;
953 struct pci_bus *linkbus = link->pdev->subordinate;
954 if (link->root != root)
956 list_for_each_entry(child, &linkbus->devices, bus_list) {
957 if ((pci_pcie_type(child) != PCI_EXP_TYPE_ENDPOINT) &&
958 (pci_pcie_type(child) != PCI_EXP_TYPE_LEG_END))
960 pcie_aspm_check_latency(child);
965 /* @pdev: the endpoint device */
966 void pcie_aspm_exit_link_state(struct pci_dev *pdev)
968 struct pci_dev *parent = pdev->bus->self;
969 struct pcie_link_state *link, *root, *parent_link;
971 if (!parent || !parent->link_state)
974 down_read(&pci_bus_sem);
975 mutex_lock(&aspm_lock);
977 link = parent->link_state;
979 parent_link = link->parent;
982 * link->downstream is a pointer to the pci_dev of function 0. If
983 * we remove that function, the pci_dev is about to be deallocated,
984 * so we can't use link->downstream again. Free the link state to
987 * If we're removing a non-0 function, it's possible we could
988 * retain the link state, but PCIe r6.0, sec 7.5.3.7, recommends
989 * programming the same ASPM Control value for all functions of
990 * multi-function devices, so disable ASPM for all of them.
992 pcie_config_aspm_link(link, 0);
993 list_del(&link->sibling);
994 free_link_state(link);
996 /* Recheck latencies and configure upstream links */
998 pcie_update_aspm_capable(root);
999 pcie_config_aspm_path(parent_link);
1002 mutex_unlock(&aspm_lock);
1003 up_read(&pci_bus_sem);
1007 * @pdev: the root port or switch downstream port
1008 * @locked: whether pci_bus_sem is held
1010 void pcie_aspm_pm_state_change(struct pci_dev *pdev, bool locked)
1012 struct pcie_link_state *link = pdev->link_state;
1014 if (aspm_disabled || !link)
1017 * Devices changed PM state, we should recheck if latency
1018 * meets all functions' requirement
1021 down_read(&pci_bus_sem);
1022 mutex_lock(&aspm_lock);
1023 pcie_update_aspm_capable(link->root);
1024 pcie_config_aspm_path(link);
1025 mutex_unlock(&aspm_lock);
1027 up_read(&pci_bus_sem);
1030 void pcie_aspm_powersave_config_link(struct pci_dev *pdev)
1032 struct pcie_link_state *link = pdev->link_state;
1034 if (aspm_disabled || !link)
1037 if (aspm_policy != POLICY_POWERSAVE &&
1038 aspm_policy != POLICY_POWER_SUPERSAVE)
1041 down_read(&pci_bus_sem);
1042 mutex_lock(&aspm_lock);
1043 pcie_config_aspm_path(link);
1044 pcie_set_clkpm(link, policy_to_clkpm_state(link));
1045 mutex_unlock(&aspm_lock);
1046 up_read(&pci_bus_sem);
1049 static struct pcie_link_state *pcie_aspm_get_link(struct pci_dev *pdev)
1051 struct pci_dev *bridge;
1053 if (!pci_is_pcie(pdev))
1056 bridge = pci_upstream_bridge(pdev);
1057 if (!bridge || !pci_is_pcie(bridge))
1060 return bridge->link_state;
1063 static int __pci_disable_link_state(struct pci_dev *pdev, int state, bool locked)
1065 struct pcie_link_state *link = pcie_aspm_get_link(pdev);
1070 * A driver requested that ASPM be disabled on this device, but
1071 * if we don't have permission to manage ASPM (e.g., on ACPI
1072 * systems we have to observe the FADT ACPI_FADT_NO_ASPM bit and
1073 * the _OSC method), we can't honor that request. Windows has
1074 * a similar mechanism using "PciASPMOptOut", which is also
1075 * ignored in this situation.
1077 if (aspm_disabled) {
1078 pci_warn(pdev, "can't disable ASPM; OS doesn't have ASPM control\n");
1083 down_read(&pci_bus_sem);
1084 mutex_lock(&aspm_lock);
1085 if (state & PCIE_LINK_STATE_L0S)
1086 link->aspm_disable |= ASPM_STATE_L0S;
1087 if (state & PCIE_LINK_STATE_L1)
1088 /* L1 PM substates require L1 */
1089 link->aspm_disable |= ASPM_STATE_L1 | ASPM_STATE_L1SS;
1090 if (state & PCIE_LINK_STATE_L1_1)
1091 link->aspm_disable |= ASPM_STATE_L1_1;
1092 if (state & PCIE_LINK_STATE_L1_2)
1093 link->aspm_disable |= ASPM_STATE_L1_2;
1094 if (state & PCIE_LINK_STATE_L1_1_PCIPM)
1095 link->aspm_disable |= ASPM_STATE_L1_1_PCIPM;
1096 if (state & PCIE_LINK_STATE_L1_2_PCIPM)
1097 link->aspm_disable |= ASPM_STATE_L1_2_PCIPM;
1098 pcie_config_aspm_link(link, policy_to_aspm_state(link));
1100 if (state & PCIE_LINK_STATE_CLKPM)
1101 link->clkpm_disable = 1;
1102 pcie_set_clkpm(link, policy_to_clkpm_state(link));
1103 mutex_unlock(&aspm_lock);
1105 up_read(&pci_bus_sem);
1110 int pci_disable_link_state_locked(struct pci_dev *pdev, int state)
1112 lockdep_assert_held_read(&pci_bus_sem);
1114 return __pci_disable_link_state(pdev, state, true);
1116 EXPORT_SYMBOL(pci_disable_link_state_locked);
1119 * pci_disable_link_state - Disable device's link state, so the link will
1120 * never enter specific states. Note that if the BIOS didn't grant ASPM
1121 * control to the OS, this does nothing because we can't touch the LNKCTL
1122 * register. Returns 0 or a negative errno.
1125 * @state: ASPM link state to disable
1127 int pci_disable_link_state(struct pci_dev *pdev, int state)
1129 return __pci_disable_link_state(pdev, state, false);
1131 EXPORT_SYMBOL(pci_disable_link_state);
1133 static int __pci_enable_link_state(struct pci_dev *pdev, int state, bool locked)
1135 struct pcie_link_state *link = pcie_aspm_get_link(pdev);
1140 * A driver requested that ASPM be enabled on this device, but
1141 * if we don't have permission to manage ASPM (e.g., on ACPI
1142 * systems we have to observe the FADT ACPI_FADT_NO_ASPM bit and
1143 * the _OSC method), we can't honor that request.
1145 if (aspm_disabled) {
1146 pci_warn(pdev, "can't override BIOS ASPM; OS doesn't have ASPM control\n");
1151 down_read(&pci_bus_sem);
1152 mutex_lock(&aspm_lock);
1153 link->aspm_default = 0;
1154 if (state & PCIE_LINK_STATE_L0S)
1155 link->aspm_default |= ASPM_STATE_L0S;
1156 if (state & PCIE_LINK_STATE_L1)
1157 link->aspm_default |= ASPM_STATE_L1;
1158 /* L1 PM substates require L1 */
1159 if (state & PCIE_LINK_STATE_L1_1)
1160 link->aspm_default |= ASPM_STATE_L1_1 | ASPM_STATE_L1;
1161 if (state & PCIE_LINK_STATE_L1_2)
1162 link->aspm_default |= ASPM_STATE_L1_2 | ASPM_STATE_L1;
1163 if (state & PCIE_LINK_STATE_L1_1_PCIPM)
1164 link->aspm_default |= ASPM_STATE_L1_1_PCIPM | ASPM_STATE_L1;
1165 if (state & PCIE_LINK_STATE_L1_2_PCIPM)
1166 link->aspm_default |= ASPM_STATE_L1_2_PCIPM | ASPM_STATE_L1;
1167 pcie_config_aspm_link(link, policy_to_aspm_state(link));
1169 link->clkpm_default = (state & PCIE_LINK_STATE_CLKPM) ? 1 : 0;
1170 pcie_set_clkpm(link, policy_to_clkpm_state(link));
1171 mutex_unlock(&aspm_lock);
1173 up_read(&pci_bus_sem);
1179 * pci_enable_link_state - Clear and set the default device link state so that
1180 * the link may be allowed to enter the specified states. Note that if the
1181 * BIOS didn't grant ASPM control to the OS, this does nothing because we can't
1182 * touch the LNKCTL register. Also note that this does not enable states
1183 * disabled by pci_disable_link_state(). Return 0 or a negative errno.
1186 * @state: Mask of ASPM link states to enable
1188 int pci_enable_link_state(struct pci_dev *pdev, int state)
1190 return __pci_enable_link_state(pdev, state, false);
1192 EXPORT_SYMBOL(pci_enable_link_state);
1195 * pci_enable_link_state_locked - Clear and set the default device link state
1196 * so that the link may be allowed to enter the specified states. Note that if
1197 * the BIOS didn't grant ASPM control to the OS, this does nothing because we
1198 * can't touch the LNKCTL register. Also note that this does not enable states
1199 * disabled by pci_disable_link_state(). Return 0 or a negative errno.
1202 * @state: Mask of ASPM link states to enable
1204 * Context: Caller holds pci_bus_sem read lock.
1206 int pci_enable_link_state_locked(struct pci_dev *pdev, int state)
1208 lockdep_assert_held_read(&pci_bus_sem);
1210 return __pci_enable_link_state(pdev, state, true);
1212 EXPORT_SYMBOL(pci_enable_link_state_locked);
1214 static int pcie_aspm_set_policy(const char *val,
1215 const struct kernel_param *kp)
1218 struct pcie_link_state *link;
1222 i = sysfs_match_string(policy_str, val);
1225 if (i == aspm_policy)
1228 down_read(&pci_bus_sem);
1229 mutex_lock(&aspm_lock);
1231 list_for_each_entry(link, &link_list, sibling) {
1232 pcie_config_aspm_link(link, policy_to_aspm_state(link));
1233 pcie_set_clkpm(link, policy_to_clkpm_state(link));
1235 mutex_unlock(&aspm_lock);
1236 up_read(&pci_bus_sem);
1240 static int pcie_aspm_get_policy(char *buffer, const struct kernel_param *kp)
1243 for (i = 0; i < ARRAY_SIZE(policy_str); i++)
1244 if (i == aspm_policy)
1245 cnt += sprintf(buffer + cnt, "[%s] ", policy_str[i]);
1247 cnt += sprintf(buffer + cnt, "%s ", policy_str[i]);
1248 cnt += sprintf(buffer + cnt, "\n");
1252 module_param_call(policy, pcie_aspm_set_policy, pcie_aspm_get_policy,
1256 * pcie_aspm_enabled - Check if PCIe ASPM has been enabled for a device.
1257 * @pdev: Target device.
1259 * Relies on the upstream bridge's link_state being valid. The link_state
1260 * is deallocated only when the last child of the bridge (i.e., @pdev or a
1261 * sibling) is removed, and the caller should be holding a reference to
1262 * @pdev, so this should be safe.
1264 bool pcie_aspm_enabled(struct pci_dev *pdev)
1266 struct pcie_link_state *link = pcie_aspm_get_link(pdev);
1271 return link->aspm_enabled;
1273 EXPORT_SYMBOL_GPL(pcie_aspm_enabled);
1275 static ssize_t aspm_attr_show_common(struct device *dev,
1276 struct device_attribute *attr,
1277 char *buf, u8 state)
1279 struct pci_dev *pdev = to_pci_dev(dev);
1280 struct pcie_link_state *link = pcie_aspm_get_link(pdev);
1282 return sysfs_emit(buf, "%d\n", (link->aspm_enabled & state) ? 1 : 0);
1285 static ssize_t aspm_attr_store_common(struct device *dev,
1286 struct device_attribute *attr,
1287 const char *buf, size_t len, u8 state)
1289 struct pci_dev *pdev = to_pci_dev(dev);
1290 struct pcie_link_state *link = pcie_aspm_get_link(pdev);
1293 if (kstrtobool(buf, &state_enable) < 0)
1296 down_read(&pci_bus_sem);
1297 mutex_lock(&aspm_lock);
1300 link->aspm_disable &= ~state;
1301 /* need to enable L1 for substates */
1302 if (state & ASPM_STATE_L1SS)
1303 link->aspm_disable &= ~ASPM_STATE_L1;
1305 link->aspm_disable |= state;
1306 if (state & ASPM_STATE_L1)
1307 link->aspm_disable |= ASPM_STATE_L1SS;
1310 pcie_config_aspm_link(link, policy_to_aspm_state(link));
1312 mutex_unlock(&aspm_lock);
1313 up_read(&pci_bus_sem);
1318 #define ASPM_ATTR(_f, _s) \
1319 static ssize_t _f##_show(struct device *dev, \
1320 struct device_attribute *attr, char *buf) \
1321 { return aspm_attr_show_common(dev, attr, buf, ASPM_STATE_##_s); } \
1323 static ssize_t _f##_store(struct device *dev, \
1324 struct device_attribute *attr, \
1325 const char *buf, size_t len) \
1326 { return aspm_attr_store_common(dev, attr, buf, len, ASPM_STATE_##_s); }
1328 ASPM_ATTR(l0s_aspm, L0S)
1329 ASPM_ATTR(l1_aspm, L1)
1330 ASPM_ATTR(l1_1_aspm, L1_1)
1331 ASPM_ATTR(l1_2_aspm, L1_2)
1332 ASPM_ATTR(l1_1_pcipm, L1_1_PCIPM)
1333 ASPM_ATTR(l1_2_pcipm, L1_2_PCIPM)
1335 static ssize_t clkpm_show(struct device *dev,
1336 struct device_attribute *attr, char *buf)
1338 struct pci_dev *pdev = to_pci_dev(dev);
1339 struct pcie_link_state *link = pcie_aspm_get_link(pdev);
1341 return sysfs_emit(buf, "%d\n", link->clkpm_enabled);
1344 static ssize_t clkpm_store(struct device *dev,
1345 struct device_attribute *attr,
1346 const char *buf, size_t len)
1348 struct pci_dev *pdev = to_pci_dev(dev);
1349 struct pcie_link_state *link = pcie_aspm_get_link(pdev);
1352 if (kstrtobool(buf, &state_enable) < 0)
1355 down_read(&pci_bus_sem);
1356 mutex_lock(&aspm_lock);
1358 link->clkpm_disable = !state_enable;
1359 pcie_set_clkpm(link, policy_to_clkpm_state(link));
1361 mutex_unlock(&aspm_lock);
1362 up_read(&pci_bus_sem);
1367 static DEVICE_ATTR_RW(clkpm);
1368 static DEVICE_ATTR_RW(l0s_aspm);
1369 static DEVICE_ATTR_RW(l1_aspm);
1370 static DEVICE_ATTR_RW(l1_1_aspm);
1371 static DEVICE_ATTR_RW(l1_2_aspm);
1372 static DEVICE_ATTR_RW(l1_1_pcipm);
1373 static DEVICE_ATTR_RW(l1_2_pcipm);
1375 static struct attribute *aspm_ctrl_attrs[] = {
1376 &dev_attr_clkpm.attr,
1377 &dev_attr_l0s_aspm.attr,
1378 &dev_attr_l1_aspm.attr,
1379 &dev_attr_l1_1_aspm.attr,
1380 &dev_attr_l1_2_aspm.attr,
1381 &dev_attr_l1_1_pcipm.attr,
1382 &dev_attr_l1_2_pcipm.attr,
1386 static umode_t aspm_ctrl_attrs_are_visible(struct kobject *kobj,
1387 struct attribute *a, int n)
1389 struct device *dev = kobj_to_dev(kobj);
1390 struct pci_dev *pdev = to_pci_dev(dev);
1391 struct pcie_link_state *link = pcie_aspm_get_link(pdev);
1392 static const u8 aspm_state_map[] = {
1397 ASPM_STATE_L1_1_PCIPM,
1398 ASPM_STATE_L1_2_PCIPM,
1401 if (aspm_disabled || !link)
1405 return link->clkpm_capable ? a->mode : 0;
1407 return link->aspm_capable & aspm_state_map[n - 1] ? a->mode : 0;
1410 const struct attribute_group aspm_ctrl_attr_group = {
1412 .attrs = aspm_ctrl_attrs,
1413 .is_visible = aspm_ctrl_attrs_are_visible,
1416 static int __init pcie_aspm_disable(char *str)
1418 if (!strcmp(str, "off")) {
1419 aspm_policy = POLICY_DEFAULT;
1421 aspm_support_enabled = false;
1422 pr_info("PCIe ASPM is disabled\n");
1423 } else if (!strcmp(str, "force")) {
1425 pr_info("PCIe ASPM is forcibly enabled\n");
1430 __setup("pcie_aspm=", pcie_aspm_disable);
1432 void pcie_no_aspm(void)
1435 * Disabling ASPM is intended to prevent the kernel from modifying
1436 * existing hardware state, not to clear existing state. To that end:
1437 * (a) set policy to POLICY_DEFAULT in order to avoid changing state
1438 * (b) prevent userspace from changing policy
1441 aspm_policy = POLICY_DEFAULT;
1446 bool pcie_aspm_support_enabled(void)
1448 return aspm_support_enabled;