drivers/infiniband/hw/hfi1/aspm.c - linux - Git at Google

 // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
 /*
  * Copyright(c) 2019 Intel Corporation.
  *
  */

 #include "aspm.h"

 /* Time after which the timer interrupt will re-enable ASPM */
 #define ASPM_TIMER_MS 1000
 /* Time for which interrupts are ignored after a timer has been scheduled */
 #define ASPM_RESCHED_TIMER_MS (ASPM_TIMER_MS / 2)
 /* Two interrupts within this time trigger ASPM disable */
 #define ASPM_TRIGGER_MS 1
 #define ASPM_TRIGGER_NS (ASPM_TRIGGER_MS * 1000 * 1000ull)
 #define ASPM_L1_SUPPORTED(reg) \
 	((((reg) & PCI_EXP_LNKCAP_ASPMS) >> 10) & 0x2)

 uint aspm_mode = ASPM_MODE_DISABLED;
 module_param_named(aspm, aspm_mode, uint, 0444);
 MODULE_PARM_DESC(aspm, "PCIe ASPM: 0: disable, 1: enable, 2: dynamic");

 static bool aspm_hw_l1_supported(struct hfi1_devdata *dd)
 {
 	struct pci_dev *parent = dd->pcidev->bus->self;
 	u32 up, dn;

 	/*
 	 * If the driver does not have access to the upstream component,
 	 * it cannot support ASPM L1 at all.
 	 */
 	if (!parent)
 		return false;

 	pcie_capability_read_dword(dd->pcidev, PCI_EXP_LNKCAP, &dn);
 	dn = ASPM_L1_SUPPORTED(dn);

 	pcie_capability_read_dword(parent, PCI_EXP_LNKCAP, &up);
 	up = ASPM_L1_SUPPORTED(up);

 	/* ASPM works on A-step but is reported as not supported */
 	return (!!dn || is_ax(dd)) && !!up;
 }

 /* Set L1 entrance latency for slower entry to L1 */
 static void aspm_hw_set_l1_ent_latency(struct hfi1_devdata *dd)
 {
 	u32 l1_ent_lat = 0x4u;
 	u32 reg32;

 	pci_read_config_dword(dd->pcidev, PCIE_CFG_REG_PL3, &reg32);
 	reg32 &= ~PCIE_CFG_REG_PL3_L1_ENT_LATENCY_SMASK;
 	reg32 |= l1_ent_lat << PCIE_CFG_REG_PL3_L1_ENT_LATENCY_SHIFT;
 	pci_write_config_dword(dd->pcidev, PCIE_CFG_REG_PL3, reg32);
 }

 static void aspm_hw_enable_l1(struct hfi1_devdata *dd)
 {
 	struct pci_dev *parent = dd->pcidev->bus->self;

 	/*
 	 * If the driver does not have access to the upstream component,
 	 * it cannot support ASPM L1 at all.
 	 */
 	if (!parent)
 		return;

 	/* Enable ASPM L1 first in upstream component and then downstream */
 	pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL,
 					   PCI_EXP_LNKCTL_ASPMC,
 					   PCI_EXP_LNKCTL_ASPM_L1);
 	pcie_capability_clear_and_set_word(dd->pcidev, PCI_EXP_LNKCTL,
 					   PCI_EXP_LNKCTL_ASPMC,
 					   PCI_EXP_LNKCTL_ASPM_L1);
 }

 void aspm_hw_disable_l1(struct hfi1_devdata *dd)
 {
 	struct pci_dev *parent = dd->pcidev->bus->self;

 	/* Disable ASPM L1 first in downstream component and then upstream */
 	pcie_capability_clear_and_set_word(dd->pcidev, PCI_EXP_LNKCTL,
 					   PCI_EXP_LNKCTL_ASPMC, 0x0);
 	if (parent)
 		pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL,
 						   PCI_EXP_LNKCTL_ASPMC, 0x0);
 }

 static  void aspm_enable(struct hfi1_devdata *dd)
 {
 	if (dd->aspm_enabled || aspm_mode == ASPM_MODE_DISABLED ||
 	    !dd->aspm_supported)
 		return;

 	aspm_hw_enable_l1(dd);
 	dd->aspm_enabled = true;
 }

 static  void aspm_disable(struct hfi1_devdata *dd)
 {
 	if (!dd->aspm_enabled || aspm_mode == ASPM_MODE_ENABLED)
 		return;

 	aspm_hw_disable_l1(dd);
 	dd->aspm_enabled = false;
 }

 static  void aspm_disable_inc(struct hfi1_devdata *dd)
 {
 	unsigned long flags;

 	spin_lock_irqsave(&dd->aspm_lock, flags);
 	aspm_disable(dd);
 	atomic_inc(&dd->aspm_disabled_cnt);
 	spin_unlock_irqrestore(&dd->aspm_lock, flags);
 }

 static  void aspm_enable_dec(struct hfi1_devdata *dd)
 {
 	unsigned long flags;

 	spin_lock_irqsave(&dd->aspm_lock, flags);
 	if (atomic_dec_and_test(&dd->aspm_disabled_cnt))
 		aspm_enable(dd);
 	spin_unlock_irqrestore(&dd->aspm_lock, flags);
 }

 /* ASPM processing for each receive context interrupt */
 void __aspm_ctx_disable(struct hfi1_ctxtdata *rcd)
 {
 	bool restart_timer;
 	bool close_interrupts;
 	unsigned long flags;
 	ktime_t now, prev;

 	spin_lock_irqsave(&rcd->aspm_lock, flags);
 	/* PSM contexts are open */
 	if (!rcd->aspm_intr_enable)
 		goto unlock;

 	prev = rcd->aspm_ts_last_intr;
 	now = ktime_get();
 	rcd->aspm_ts_last_intr = now;

 	/* An interrupt pair close together in time */
 	close_interrupts = ktime_to_ns(ktime_sub(now, prev)) < ASPM_TRIGGER_NS;

 	/* Don't push out our timer till this much time has elapsed */
 	restart_timer = ktime_to_ns(ktime_sub(now, rcd->aspm_ts_timer_sched)) >
 				    ASPM_RESCHED_TIMER_MS * NSEC_PER_MSEC;
 	restart_timer = restart_timer && close_interrupts;

 	/* Disable ASPM and schedule timer */
 	if (rcd->aspm_enabled && close_interrupts) {
 		aspm_disable_inc(rcd->dd);
 		rcd->aspm_enabled = false;
 		restart_timer = true;
 	}

 	if (restart_timer) {
 		mod_timer(&rcd->aspm_timer,
 			  jiffies + msecs_to_jiffies(ASPM_TIMER_MS));
 		rcd->aspm_ts_timer_sched = now;
 	}
 unlock:
 	spin_unlock_irqrestore(&rcd->aspm_lock, flags);
 }

 /* Timer function for re-enabling ASPM in the absence of interrupt activity */
 static  void aspm_ctx_timer_function(struct timer_list *t)
 {
 	struct hfi1_ctxtdata *rcd = from_timer(rcd, t, aspm_timer);
 	unsigned long flags;

 	spin_lock_irqsave(&rcd->aspm_lock, flags);
 	aspm_enable_dec(rcd->dd);
 	rcd->aspm_enabled = true;
 	spin_unlock_irqrestore(&rcd->aspm_lock, flags);
 }

 /*
  * Disable interrupt processing for verbs contexts when PSM or VNIC contexts
  * are open.
  */
 void aspm_disable_all(struct hfi1_devdata *dd)
 {
 	struct hfi1_ctxtdata *rcd;
 	unsigned long flags;
 	u16 i;

 	for (i = 0; i < dd->first_dyn_alloc_ctxt; i++) {
 		rcd = hfi1_rcd_get_by_index(dd, i);
 		if (rcd) {
 			del_timer_sync(&rcd->aspm_timer);
 			spin_lock_irqsave(&rcd->aspm_lock, flags);
 			rcd->aspm_intr_enable = false;
 			spin_unlock_irqrestore(&rcd->aspm_lock, flags);
 			hfi1_rcd_put(rcd);
 		}
 	}

 	aspm_disable(dd);
 	atomic_set(&dd->aspm_disabled_cnt, 0);
 }

 /* Re-enable interrupt processing for verbs contexts */
 void aspm_enable_all(struct hfi1_devdata *dd)
 {
 	struct hfi1_ctxtdata *rcd;
 	unsigned long flags;
 	u16 i;

 	aspm_enable(dd);

 	if (aspm_mode != ASPM_MODE_DYNAMIC)
 		return;

 	for (i = 0; i < dd->first_dyn_alloc_ctxt; i++) {
 		rcd = hfi1_rcd_get_by_index(dd, i);
 		if (rcd) {
 			spin_lock_irqsave(&rcd->aspm_lock, flags);
 			rcd->aspm_intr_enable = true;
 			rcd->aspm_enabled = true;
 			spin_unlock_irqrestore(&rcd->aspm_lock, flags);
 			hfi1_rcd_put(rcd);
 		}
 	}
 }

 static  void aspm_ctx_init(struct hfi1_ctxtdata *rcd)
 {
 	spin_lock_init(&rcd->aspm_lock);
 	timer_setup(&rcd->aspm_timer, aspm_ctx_timer_function, 0);
 	rcd->aspm_intr_supported = rcd->dd->aspm_supported &&
 		aspm_mode == ASPM_MODE_DYNAMIC &&
 		rcd->ctxt < rcd->dd->first_dyn_alloc_ctxt;
 }

 void aspm_init(struct hfi1_devdata *dd)
 {
 	struct hfi1_ctxtdata *rcd;
 	u16 i;

 	spin_lock_init(&dd->aspm_lock);
 	dd->aspm_supported = aspm_hw_l1_supported(dd);

 	for (i = 0; i < dd->first_dyn_alloc_ctxt; i++) {
 		rcd = hfi1_rcd_get_by_index(dd, i);
 		if (rcd)
 			aspm_ctx_init(rcd);
 		hfi1_rcd_put(rcd);
 	}

 	/* Start with ASPM disabled */
 	aspm_hw_set_l1_ent_latency(dd);
 	dd->aspm_enabled = false;
 	aspm_hw_disable_l1(dd);

 	/* Now turn on ASPM if configured */
 	aspm_enable_all(dd);
 }

 void aspm_exit(struct hfi1_devdata *dd)
 {
 	aspm_disable_all(dd);

 	/* Turn on ASPM on exit to conserve power */
 	aspm_enable(dd);
 }
	// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
	/*
	* Copyright(c) 2019 Intel Corporation.
	*
	*/

	#include "aspm.h"

	/* Time after which the timer interrupt will re-enable ASPM */
	#define ASPM_TIMER_MS 1000
	/* Time for which interrupts are ignored after a timer has been scheduled */
	#define ASPM_RESCHED_TIMER_MS (ASPM_TIMER_MS / 2)
	/* Two interrupts within this time trigger ASPM disable */
	#define ASPM_TRIGGER_MS 1
	#define ASPM_TRIGGER_NS (ASPM_TRIGGER_MS * 1000 * 1000ull)
	#define ASPM_L1_SUPPORTED(reg) \
	((((reg) & PCI_EXP_LNKCAP_ASPMS) >> 10) & 0x2)

	uint aspm_mode = ASPM_MODE_DISABLED;
	module_param_named(aspm, aspm_mode, uint, 0444);
	MODULE_PARM_DESC(aspm, "PCIe ASPM: 0: disable, 1: enable, 2: dynamic");

	static bool aspm_hw_l1_supported(struct hfi1_devdata *dd)
	{
	struct pci_dev *parent = dd->pcidev->bus->self;
	u32 up, dn;

	/*
	* If the driver does not have access to the upstream component,
	* it cannot support ASPM L1 at all.
	*/
	if (!parent)
	return false;

	pcie_capability_read_dword(dd->pcidev, PCI_EXP_LNKCAP, &dn);
	dn = ASPM_L1_SUPPORTED(dn);

	pcie_capability_read_dword(parent, PCI_EXP_LNKCAP, &up);
	up = ASPM_L1_SUPPORTED(up);

	/* ASPM works on A-step but is reported as not supported */
	return (!!dn \|\| is_ax(dd)) && !!up;
	}

	/* Set L1 entrance latency for slower entry to L1 */
	static void aspm_hw_set_l1_ent_latency(struct hfi1_devdata *dd)
	{
	u32 l1_ent_lat = 0x4u;
	u32 reg32;

	pci_read_config_dword(dd->pcidev, PCIE_CFG_REG_PL3, &reg32);
	reg32 &= ~PCIE_CFG_REG_PL3_L1_ENT_LATENCY_SMASK;
	reg32 \|= l1_ent_lat << PCIE_CFG_REG_PL3_L1_ENT_LATENCY_SHIFT;
	pci_write_config_dword(dd->pcidev, PCIE_CFG_REG_PL3, reg32);
	}

	static void aspm_hw_enable_l1(struct hfi1_devdata *dd)
	{
	struct pci_dev *parent = dd->pcidev->bus->self;

	/*
	* If the driver does not have access to the upstream component,
	* it cannot support ASPM L1 at all.
	*/
	if (!parent)
	return;

	/* Enable ASPM L1 first in upstream component and then downstream */
	pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL,
	PCI_EXP_LNKCTL_ASPMC,
	PCI_EXP_LNKCTL_ASPM_L1);
	pcie_capability_clear_and_set_word(dd->pcidev, PCI_EXP_LNKCTL,
	PCI_EXP_LNKCTL_ASPMC,
	PCI_EXP_LNKCTL_ASPM_L1);
	}

	void aspm_hw_disable_l1(struct hfi1_devdata *dd)
	{
	struct pci_dev *parent = dd->pcidev->bus->self;

	/* Disable ASPM L1 first in downstream component and then upstream */
	pcie_capability_clear_and_set_word(dd->pcidev, PCI_EXP_LNKCTL,
	PCI_EXP_LNKCTL_ASPMC, 0x0);
	if (parent)
	pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL,
	PCI_EXP_LNKCTL_ASPMC, 0x0);
	}

	static void aspm_enable(struct hfi1_devdata *dd)
	{
	if (dd->aspm_enabled \|\| aspm_mode == ASPM_MODE_DISABLED \|\|
	!dd->aspm_supported)
	return;

	aspm_hw_enable_l1(dd);
	dd->aspm_enabled = true;
	}

	static void aspm_disable(struct hfi1_devdata *dd)
	{
	if (!dd->aspm_enabled \|\| aspm_mode == ASPM_MODE_ENABLED)
	return;

	aspm_hw_disable_l1(dd);
	dd->aspm_enabled = false;
	}

	static void aspm_disable_inc(struct hfi1_devdata *dd)
	{
	unsigned long flags;

	spin_lock_irqsave(&dd->aspm_lock, flags);
	aspm_disable(dd);
	atomic_inc(&dd->aspm_disabled_cnt);
	spin_unlock_irqrestore(&dd->aspm_lock, flags);
	}

	static void aspm_enable_dec(struct hfi1_devdata *dd)
	{
	unsigned long flags;

	spin_lock_irqsave(&dd->aspm_lock, flags);
	if (atomic_dec_and_test(&dd->aspm_disabled_cnt))
	aspm_enable(dd);
	spin_unlock_irqrestore(&dd->aspm_lock, flags);
	}

	/* ASPM processing for each receive context interrupt */
	void __aspm_ctx_disable(struct hfi1_ctxtdata *rcd)
	{
	bool restart_timer;
	bool close_interrupts;
	unsigned long flags;
	ktime_t now, prev;

	spin_lock_irqsave(&rcd->aspm_lock, flags);
	/* PSM contexts are open */
	if (!rcd->aspm_intr_enable)
	goto unlock;

	prev = rcd->aspm_ts_last_intr;
	now = ktime_get();
	rcd->aspm_ts_last_intr = now;

	/* An interrupt pair close together in time */
	close_interrupts = ktime_to_ns(ktime_sub(now, prev)) < ASPM_TRIGGER_NS;

	/* Don't push out our timer till this much time has elapsed */
	restart_timer = ktime_to_ns(ktime_sub(now, rcd->aspm_ts_timer_sched)) >
	ASPM_RESCHED_TIMER_MS * NSEC_PER_MSEC;
	restart_timer = restart_timer && close_interrupts;

	/* Disable ASPM and schedule timer */
	if (rcd->aspm_enabled && close_interrupts) {
	aspm_disable_inc(rcd->dd);
	rcd->aspm_enabled = false;
	restart_timer = true;
	}

	if (restart_timer) {
	mod_timer(&rcd->aspm_timer,
	jiffies + msecs_to_jiffies(ASPM_TIMER_MS));
	rcd->aspm_ts_timer_sched = now;
	}
	unlock:
	spin_unlock_irqrestore(&rcd->aspm_lock, flags);
	}

	/* Timer function for re-enabling ASPM in the absence of interrupt activity */
	static void aspm_ctx_timer_function(struct timer_list *t)
	{
	struct hfi1_ctxtdata *rcd = from_timer(rcd, t, aspm_timer);
	unsigned long flags;

	spin_lock_irqsave(&rcd->aspm_lock, flags);
	aspm_enable_dec(rcd->dd);
	rcd->aspm_enabled = true;
	spin_unlock_irqrestore(&rcd->aspm_lock, flags);
	}

	/*
	* Disable interrupt processing for verbs contexts when PSM or VNIC contexts
	* are open.
	*/
	void aspm_disable_all(struct hfi1_devdata *dd)
	{
	struct hfi1_ctxtdata *rcd;
	unsigned long flags;
	u16 i;

	for (i = 0; i < dd->first_dyn_alloc_ctxt; i++) {
	rcd = hfi1_rcd_get_by_index(dd, i);
	if (rcd) {
	del_timer_sync(&rcd->aspm_timer);
	spin_lock_irqsave(&rcd->aspm_lock, flags);
	rcd->aspm_intr_enable = false;
	spin_unlock_irqrestore(&rcd->aspm_lock, flags);
	hfi1_rcd_put(rcd);
	}
	}

	aspm_disable(dd);
	atomic_set(&dd->aspm_disabled_cnt, 0);
	}

	/* Re-enable interrupt processing for verbs contexts */
	void aspm_enable_all(struct hfi1_devdata *dd)
	{
	struct hfi1_ctxtdata *rcd;
	unsigned long flags;
	u16 i;

	aspm_enable(dd);

	if (aspm_mode != ASPM_MODE_DYNAMIC)
	return;

	for (i = 0; i < dd->first_dyn_alloc_ctxt; i++) {
	rcd = hfi1_rcd_get_by_index(dd, i);
	if (rcd) {
	spin_lock_irqsave(&rcd->aspm_lock, flags);
	rcd->aspm_intr_enable = true;
	rcd->aspm_enabled = true;
	spin_unlock_irqrestore(&rcd->aspm_lock, flags);
	hfi1_rcd_put(rcd);
	}
	}
	}

	static void aspm_ctx_init(struct hfi1_ctxtdata *rcd)
	{
	spin_lock_init(&rcd->aspm_lock);
	timer_setup(&rcd->aspm_timer, aspm_ctx_timer_function, 0);
	rcd->aspm_intr_supported = rcd->dd->aspm_supported &&
	aspm_mode == ASPM_MODE_DYNAMIC &&
	rcd->ctxt < rcd->dd->first_dyn_alloc_ctxt;
	}

	void aspm_init(struct hfi1_devdata *dd)
	{
	struct hfi1_ctxtdata *rcd;
	u16 i;

	spin_lock_init(&dd->aspm_lock);
	dd->aspm_supported = aspm_hw_l1_supported(dd);

	for (i = 0; i < dd->first_dyn_alloc_ctxt; i++) {
	rcd = hfi1_rcd_get_by_index(dd, i);
	if (rcd)
	aspm_ctx_init(rcd);
	hfi1_rcd_put(rcd);
	}

	/* Start with ASPM disabled */
	aspm_hw_set_l1_ent_latency(dd);
	dd->aspm_enabled = false;
	aspm_hw_disable_l1(dd);

	/* Now turn on ASPM if configured */
	aspm_enable_all(dd);
	}

	void aspm_exit(struct hfi1_devdata *dd)
	{
	aspm_disable_all(dd);

	/* Turn on ASPM on exit to conserve power */
	aspm_enable(dd);
	}