drivers/net/ipa/ipa_power.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0

 /* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
  * Copyright (C) 2018-2022 Linaro Ltd.
  */

 #include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/interconnect.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
 #include <linux/bitops.h>

 #include "linux/soc/qcom/qcom_aoss.h"

 #include "ipa.h"
 #include "ipa_power.h"
 #include "ipa_endpoint.h"
 #include "ipa_modem.h"
 #include "ipa_data.h"

 /**
  * DOC: IPA Power Management
  *
  * The IPA hardware is enabled when the IPA core clock and all the
  * interconnects (buses) it depends on are enabled.  Runtime power
  * management is used to determine whether the core clock and
  * interconnects are enabled, and if not in use to be suspended
  * automatically.
  *
  * The core clock currently runs at a fixed clock rate when enabled,
  * an all interconnects use a fixed average and peak bandwidth.
  */

 #define IPA_AUTOSUSPEND_DELAY	500	/* milliseconds */

 /**
  * enum ipa_power_flag - IPA power flags
  * @IPA_POWER_FLAG_RESUMED:	Whether resume from suspend has been signaled
  * @IPA_POWER_FLAG_SYSTEM:	Hardware is system (not runtime) suspended
  * @IPA_POWER_FLAG_STOPPED:	Modem TX is disabled by ipa_start_xmit()
  * @IPA_POWER_FLAG_STARTED:	Modem TX was enabled by ipa_runtime_resume()
  * @IPA_POWER_FLAG_COUNT:	Number of defined power flags
  */
 enum ipa_power_flag {
 	IPA_POWER_FLAG_RESUMED,
 	IPA_POWER_FLAG_SYSTEM,
 	IPA_POWER_FLAG_STOPPED,
 	IPA_POWER_FLAG_STARTED,
 	IPA_POWER_FLAG_COUNT,		/* Last; not a flag */
 };

 /**
  * struct ipa_power - IPA power management information
  * @dev:		IPA device pointer
  * @core:		IPA core clock
  * @qmp:		QMP handle for AOSS communication
  * @spinlock:		Protects modem TX queue enable/disable
  * @flags:		Boolean state flags
  * @interconnect_count:	Number of elements in interconnect[]
  * @interconnect:	Interconnect array
  */
 struct ipa_power {
 	struct device *dev;
 	struct clk *core;
 	struct qmp *qmp;
 	spinlock_t spinlock;	/* used with STOPPED/STARTED power flags */
 	DECLARE_BITMAP(flags, IPA_POWER_FLAG_COUNT);
 	u32 interconnect_count;
 	struct icc_bulk_data interconnect[];
 };

 /* Initialize interconnects required for IPA operation */
 static int ipa_interconnect_init(struct ipa_power *power,
 				 const struct ipa_interconnect_data *data)
 {
 	struct icc_bulk_data *interconnect;
 	int ret;
 	u32 i;

 	/* Initialize our interconnect data array for bulk operations */
 	interconnect = &power->interconnect[0];
 	for (i = 0; i < power->interconnect_count; i++) {
 		/* interconnect->path is filled in by of_icc_bulk_get() */
 		interconnect->name = data->name;
 		interconnect->avg_bw = data->average_bandwidth;
 		interconnect->peak_bw = data->peak_bandwidth;
 		data++;
 		interconnect++;
 	}

 	ret = of_icc_bulk_get(power->dev, power->interconnect_count,
 			      power->interconnect);
 	if (ret)
 		return ret;

 	/* All interconnects are initially disabled */
 	icc_bulk_disable(power->interconnect_count, power->interconnect);

 	/* Set the bandwidth values to be used when enabled */
 	ret = icc_bulk_set_bw(power->interconnect_count, power->interconnect);
 	if (ret)
 		icc_bulk_put(power->interconnect_count, power->interconnect);

 	return ret;
 }

 /* Inverse of ipa_interconnect_init() */
 static void ipa_interconnect_exit(struct ipa_power *power)
 {
 	icc_bulk_put(power->interconnect_count, power->interconnect);
 }

 /* Enable IPA power, enabling interconnects and the core clock */
 static int ipa_power_enable(struct ipa *ipa)
 {
 	struct ipa_power *power = ipa->power;
 	int ret;

 	ret = icc_bulk_enable(power->interconnect_count, power->interconnect);
 	if (ret)
 		return ret;

 	ret = clk_prepare_enable(power->core);
 	if (ret) {
 		dev_err(power->dev, "error %d enabling core clock\n", ret);
 		icc_bulk_disable(power->interconnect_count,
 				 power->interconnect);
 	}

 	return ret;
 }

 /* Inverse of ipa_power_enable() */
 static void ipa_power_disable(struct ipa *ipa)
 {
 	struct ipa_power *power = ipa->power;

 	clk_disable_unprepare(power->core);

 	icc_bulk_disable(power->interconnect_count, power->interconnect);
 }

 static int ipa_runtime_suspend(struct device *dev)
 {
 	struct ipa *ipa = dev_get_drvdata(dev);

 	/* Endpoints aren't usable until setup is complete */
 	if (ipa->setup_complete) {
 		__clear_bit(IPA_POWER_FLAG_RESUMED, ipa->power->flags);
 		ipa_endpoint_suspend(ipa);
 		gsi_suspend(&ipa->gsi);
 	}

 	ipa_power_disable(ipa);

 	return 0;
 }

 static int ipa_runtime_resume(struct device *dev)
 {
 	struct ipa *ipa = dev_get_drvdata(dev);
 	int ret;

 	ret = ipa_power_enable(ipa);
 	if (WARN_ON(ret < 0))
 		return ret;

 	/* Endpoints aren't usable until setup is complete */
 	if (ipa->setup_complete) {
 		gsi_resume(&ipa->gsi);
 		ipa_endpoint_resume(ipa);
 	}

 	return 0;
 }

 static int ipa_suspend(struct device *dev)
 {
 	struct ipa *ipa = dev_get_drvdata(dev);

 	__set_bit(IPA_POWER_FLAG_SYSTEM, ipa->power->flags);

 	/* Increment the disable depth to ensure that the IRQ won't
 	 * be re-enabled until the matching _enable call in
 	 * ipa_resume(). We do this to ensure that the interrupt
 	 * handler won't run whilst PM runtime is disabled.
 	 *
 	 * Note that disabling the IRQ is NOT the same as disabling
 	 * irq wake. If wakeup is enabled for the IPA then the IRQ
 	 * will still cause the system to wake up, see irq_set_irq_wake().
 	 */
 	ipa_interrupt_irq_disable(ipa);

 	return pm_runtime_force_suspend(dev);
 }

 static int ipa_resume(struct device *dev)
 {
 	struct ipa *ipa = dev_get_drvdata(dev);
 	int ret;

 	ret = pm_runtime_force_resume(dev);

 	__clear_bit(IPA_POWER_FLAG_SYSTEM, ipa->power->flags);

 	/* Now that PM runtime is enabled again it's safe
 	 * to turn the IRQ back on and process any data
 	 * that was received during suspend.
 	 */
 	ipa_interrupt_irq_enable(ipa);

 	return ret;
 }

 /* Return the current IPA core clock rate */
 u32 ipa_core_clock_rate(struct ipa *ipa)
 {
 	return ipa->power ? (u32)clk_get_rate(ipa->power->core) : 0;
 }

 void ipa_power_suspend_handler(struct ipa *ipa, enum ipa_irq_id irq_id)
 {
 	/* To handle an IPA interrupt we will have resumed the hardware
 	 * just to handle the interrupt, so we're done.  If we are in a
 	 * system suspend, trigger a system resume.
 	 */
 	if (!__test_and_set_bit(IPA_POWER_FLAG_RESUMED, ipa->power->flags))
 		if (test_bit(IPA_POWER_FLAG_SYSTEM, ipa->power->flags))
 			pm_wakeup_dev_event(&ipa->pdev->dev, 0, true);

 	/* Acknowledge/clear the suspend interrupt on all endpoints */
 	ipa_interrupt_suspend_clear_all(ipa->interrupt);
 }

 /* The next few functions coordinate stopping and starting the modem
  * network device transmit queue.
  *
  * Transmit can be running concurrent with power resume, and there's a
  * chance the resume completes before the transmit path stops the queue,
  * leaving the queue in a stopped state.  The next two functions are used
  * to avoid this: ipa_power_modem_queue_stop() is used by ipa_start_xmit()
  * to conditionally stop the TX queue; and ipa_power_modem_queue_start()
  * is used by ipa_runtime_resume() to conditionally restart it.
  *
  * Two flags and a spinlock are used.  If the queue is stopped, the STOPPED
  * power flag is set.  And if the queue is started, the STARTED flag is set.
  * The queue is only started on resume if the STOPPED flag is set.  And the
  * queue is only started in ipa_start_xmit() if the STARTED flag is *not*
  * set.  As a result, the queue remains operational if the two activites
  * happen concurrently regardless of the order they complete.  The spinlock
  * ensures the flag and TX queue operations are done atomically.
  *
  * The first function stops the modem netdev transmit queue, but only if
  * the STARTED flag is *not* set.  That flag is cleared if it was set.
  * If the queue is stopped, the STOPPED flag is set.  This is called only
  * from the power ->runtime_resume operation.
  */
 void ipa_power_modem_queue_stop(struct ipa *ipa)
 {
 	struct ipa_power *power = ipa->power;
 	unsigned long flags;

 	spin_lock_irqsave(&power->spinlock, flags);

 	if (!__test_and_clear_bit(IPA_POWER_FLAG_STARTED, power->flags)) {
 		netif_stop_queue(ipa->modem_netdev);
 		__set_bit(IPA_POWER_FLAG_STOPPED, power->flags);
 	}

 	spin_unlock_irqrestore(&power->spinlock, flags);
 }

 /* This function starts the modem netdev transmit queue, but only if the
  * STOPPED flag is set.  That flag is cleared if it was set.  If the queue
  * was restarted, the STARTED flag is set; this allows ipa_start_xmit()
  * to skip stopping the queue in the event of a race.
  */
 void ipa_power_modem_queue_wake(struct ipa *ipa)
 {
 	struct ipa_power *power = ipa->power;
 	unsigned long flags;

 	spin_lock_irqsave(&power->spinlock, flags);

 	if (__test_and_clear_bit(IPA_POWER_FLAG_STOPPED, power->flags)) {
 		__set_bit(IPA_POWER_FLAG_STARTED, power->flags);
 		netif_wake_queue(ipa->modem_netdev);
 	}

 	spin_unlock_irqrestore(&power->spinlock, flags);
 }

 /* This function clears the STARTED flag once the TX queue is operating */
 void ipa_power_modem_queue_active(struct ipa *ipa)
 {
 	clear_bit(IPA_POWER_FLAG_STARTED, ipa->power->flags);
 }

 static int ipa_power_retention_init(struct ipa_power *power)
 {
 	struct qmp *qmp = qmp_get(power->dev);

 	if (IS_ERR(qmp)) {
 		if (PTR_ERR(qmp) == -EPROBE_DEFER)
 			return -EPROBE_DEFER;

 		/* We assume any other error means it's not defined/needed */
 		qmp = NULL;
 	}
 	power->qmp = qmp;

 	return 0;
 }

 static void ipa_power_retention_exit(struct ipa_power *power)
 {
 	qmp_put(power->qmp);
 	power->qmp = NULL;
 }

 /* Control register retention on power collapse */
 void ipa_power_retention(struct ipa *ipa, bool enable)
 {
 	static const char fmt[] = "{ class: bcm, res: ipa_pc, val: %c }";
 	struct ipa_power *power = ipa->power;
 	char buf[36];	/* Exactly enough for fmt[]; size a multiple of 4 */
 	int ret;

 	if (!power->qmp)
 		return;		/* Not needed on this platform */

 	(void)snprintf(buf, sizeof(buf), fmt, enable ? '1' : '0');

 	ret = qmp_send(power->qmp, buf, sizeof(buf));
 	if (ret)
 		dev_err(power->dev, "error %d sending QMP %sable request\n",
 			ret, enable ? "en" : "dis");
 }

 int ipa_power_setup(struct ipa *ipa)
 {
 	int ret;

 	ipa_interrupt_enable(ipa, IPA_IRQ_TX_SUSPEND);

 	ret = device_init_wakeup(&ipa->pdev->dev, true);
 	if (ret)
 		ipa_interrupt_disable(ipa, IPA_IRQ_TX_SUSPEND);

 	return ret;
 }

 void ipa_power_teardown(struct ipa *ipa)
 {
 	(void)device_init_wakeup(&ipa->pdev->dev, false);
 	ipa_interrupt_disable(ipa, IPA_IRQ_TX_SUSPEND);
 }

 /* Initialize IPA power management */
 struct ipa_power *
 ipa_power_init(struct device *dev, const struct ipa_power_data *data)
 {
 	struct ipa_power *power;
 	struct clk *clk;
 	size_t size;
 	int ret;

 	clk = clk_get(dev, "core");
 	if (IS_ERR(clk)) {
 		dev_err_probe(dev, PTR_ERR(clk), "error getting core clock\n");

 		return ERR_CAST(clk);
 	}

 	ret = clk_set_rate(clk, data->core_clock_rate);
 	if (ret) {
 		dev_err(dev, "error %d setting core clock rate to %u\n",
 			ret, data->core_clock_rate);
 		goto err_clk_put;
 	}

 	size = struct_size(power, interconnect, data->interconnect_count);
 	power = kzalloc(size, GFP_KERNEL);
 	if (!power) {
 		ret = -ENOMEM;
 		goto err_clk_put;
 	}
 	power->dev = dev;
 	power->core = clk;
 	spin_lock_init(&power->spinlock);
 	power->interconnect_count = data->interconnect_count;

 	ret = ipa_interconnect_init(power, data->interconnect_data);
 	if (ret)
 		goto err_kfree;

 	ret = ipa_power_retention_init(power);
 	if (ret)
 		goto err_interconnect_exit;

 	pm_runtime_set_autosuspend_delay(dev, IPA_AUTOSUSPEND_DELAY);
 	pm_runtime_use_autosuspend(dev);
 	pm_runtime_enable(dev);

 	return power;

 err_interconnect_exit:
 	ipa_interconnect_exit(power);
 err_kfree:
 	kfree(power);
 err_clk_put:
 	clk_put(clk);

 	return ERR_PTR(ret);
 }

 /* Inverse of ipa_power_init() */
 void ipa_power_exit(struct ipa_power *power)
 {
 	struct device *dev = power->dev;
 	struct clk *clk = power->core;

 	pm_runtime_disable(dev);
 	pm_runtime_dont_use_autosuspend(dev);
 	ipa_power_retention_exit(power);
 	ipa_interconnect_exit(power);
 	kfree(power);
 	clk_put(clk);
 }

 const struct dev_pm_ops ipa_pm_ops = {
 	.suspend		= ipa_suspend,
 	.resume			= ipa_resume,
 	.runtime_suspend	= ipa_runtime_suspend,
 	.runtime_resume		= ipa_runtime_resume,
 };
	// SPDX-License-Identifier: GPL-2.0

	/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
	* Copyright (C) 2018-2022 Linaro Ltd.
	*/

	#include <linux/clk.h>
	#include <linux/device.h>
	#include <linux/interconnect.h>
	#include <linux/pm.h>
	#include <linux/pm_runtime.h>
	#include <linux/bitops.h>

	#include "linux/soc/qcom/qcom_aoss.h"

	#include "ipa.h"
	#include "ipa_power.h"
	#include "ipa_endpoint.h"
	#include "ipa_modem.h"
	#include "ipa_data.h"

	/**
	* DOC: IPA Power Management
	*
	* The IPA hardware is enabled when the IPA core clock and all the
	* interconnects (buses) it depends on are enabled. Runtime power
	* management is used to determine whether the core clock and
	* interconnects are enabled, and if not in use to be suspended
	* automatically.
	*
	* The core clock currently runs at a fixed clock rate when enabled,
	* an all interconnects use a fixed average and peak bandwidth.
	*/

	#define IPA_AUTOSUSPEND_DELAY 500 /* milliseconds */

	/**
	* enum ipa_power_flag - IPA power flags
	* @IPA_POWER_FLAG_RESUMED: Whether resume from suspend has been signaled
	* @IPA_POWER_FLAG_SYSTEM: Hardware is system (not runtime) suspended
	* @IPA_POWER_FLAG_STOPPED: Modem TX is disabled by ipa_start_xmit()
	* @IPA_POWER_FLAG_STARTED: Modem TX was enabled by ipa_runtime_resume()
	* @IPA_POWER_FLAG_COUNT: Number of defined power flags
	*/
	enum ipa_power_flag {
	IPA_POWER_FLAG_RESUMED,
	IPA_POWER_FLAG_SYSTEM,
	IPA_POWER_FLAG_STOPPED,
	IPA_POWER_FLAG_STARTED,
	IPA_POWER_FLAG_COUNT, /* Last; not a flag */
	};

	/**
	* struct ipa_power - IPA power management information
	* @dev: IPA device pointer
	* @core: IPA core clock
	* @qmp: QMP handle for AOSS communication
	* @spinlock: Protects modem TX queue enable/disable
	* @flags: Boolean state flags
	* @interconnect_count: Number of elements in interconnect[]
	* @interconnect: Interconnect array
	*/
	struct ipa_power {
	struct device *dev;
	struct clk *core;
	struct qmp *qmp;
	spinlock_t spinlock; /* used with STOPPED/STARTED power flags */
	DECLARE_BITMAP(flags, IPA_POWER_FLAG_COUNT);
	u32 interconnect_count;
	struct icc_bulk_data interconnect[];
	};

	/* Initialize interconnects required for IPA operation */
	static int ipa_interconnect_init(struct ipa_power *power,
	const struct ipa_interconnect_data *data)
	{
	struct icc_bulk_data *interconnect;
	int ret;
	u32 i;

	/* Initialize our interconnect data array for bulk operations */
	interconnect = &power->interconnect[0];
	for (i = 0; i < power->interconnect_count; i++) {
	/* interconnect->path is filled in by of_icc_bulk_get() */
	interconnect->name = data->name;
	interconnect->avg_bw = data->average_bandwidth;
	interconnect->peak_bw = data->peak_bandwidth;
	data++;
	interconnect++;
	}

	ret = of_icc_bulk_get(power->dev, power->interconnect_count,
	power->interconnect);
	if (ret)
	return ret;

	/* All interconnects are initially disabled */
	icc_bulk_disable(power->interconnect_count, power->interconnect);

	/* Set the bandwidth values to be used when enabled */
	ret = icc_bulk_set_bw(power->interconnect_count, power->interconnect);
	if (ret)
	icc_bulk_put(power->interconnect_count, power->interconnect);

	return ret;
	}

	/* Inverse of ipa_interconnect_init() */
	static void ipa_interconnect_exit(struct ipa_power *power)
	{
	icc_bulk_put(power->interconnect_count, power->interconnect);
	}

	/* Enable IPA power, enabling interconnects and the core clock */
	static int ipa_power_enable(struct ipa *ipa)
	{
	struct ipa_power *power = ipa->power;
	int ret;

	ret = icc_bulk_enable(power->interconnect_count, power->interconnect);
	if (ret)
	return ret;

	ret = clk_prepare_enable(power->core);
	if (ret) {
	dev_err(power->dev, "error %d enabling core clock\n", ret);
	icc_bulk_disable(power->interconnect_count,
	power->interconnect);
	}

	return ret;
	}

	/* Inverse of ipa_power_enable() */
	static void ipa_power_disable(struct ipa *ipa)
	{
	struct ipa_power *power = ipa->power;

	clk_disable_unprepare(power->core);

	icc_bulk_disable(power->interconnect_count, power->interconnect);
	}

	static int ipa_runtime_suspend(struct device *dev)
	{
	struct ipa *ipa = dev_get_drvdata(dev);

	/* Endpoints aren't usable until setup is complete */
	if (ipa->setup_complete) {
	__clear_bit(IPA_POWER_FLAG_RESUMED, ipa->power->flags);
	ipa_endpoint_suspend(ipa);
	gsi_suspend(&ipa->gsi);
	}

	ipa_power_disable(ipa);

	return 0;
	}

	static int ipa_runtime_resume(struct device *dev)
	{
	struct ipa *ipa = dev_get_drvdata(dev);
	int ret;

	ret = ipa_power_enable(ipa);
	if (WARN_ON(ret < 0))
	return ret;

	/* Endpoints aren't usable until setup is complete */
	if (ipa->setup_complete) {
	gsi_resume(&ipa->gsi);
	ipa_endpoint_resume(ipa);
	}

	return 0;
	}

	static int ipa_suspend(struct device *dev)
	{
	struct ipa *ipa = dev_get_drvdata(dev);

	__set_bit(IPA_POWER_FLAG_SYSTEM, ipa->power->flags);

	/* Increment the disable depth to ensure that the IRQ won't
	* be re-enabled until the matching _enable call in
	* ipa_resume(). We do this to ensure that the interrupt
	* handler won't run whilst PM runtime is disabled.
	*
	* Note that disabling the IRQ is NOT the same as disabling
	* irq wake. If wakeup is enabled for the IPA then the IRQ
	* will still cause the system to wake up, see irq_set_irq_wake().
	*/
	ipa_interrupt_irq_disable(ipa);

	return pm_runtime_force_suspend(dev);
	}

	static int ipa_resume(struct device *dev)
	{
	struct ipa *ipa = dev_get_drvdata(dev);
	int ret;

	ret = pm_runtime_force_resume(dev);

	__clear_bit(IPA_POWER_FLAG_SYSTEM, ipa->power->flags);

	/* Now that PM runtime is enabled again it's safe
	* to turn the IRQ back on and process any data
	* that was received during suspend.
	*/
	ipa_interrupt_irq_enable(ipa);

	return ret;
	}

	/* Return the current IPA core clock rate */
	u32 ipa_core_clock_rate(struct ipa *ipa)
	{
	return ipa->power ? (u32)clk_get_rate(ipa->power->core) : 0;
	}

	void ipa_power_suspend_handler(struct ipa *ipa, enum ipa_irq_id irq_id)
	{
	/* To handle an IPA interrupt we will have resumed the hardware
	* just to handle the interrupt, so we're done. If we are in a
	* system suspend, trigger a system resume.
	*/
	if (!__test_and_set_bit(IPA_POWER_FLAG_RESUMED, ipa->power->flags))
	if (test_bit(IPA_POWER_FLAG_SYSTEM, ipa->power->flags))
	pm_wakeup_dev_event(&ipa->pdev->dev, 0, true);

	/* Acknowledge/clear the suspend interrupt on all endpoints */
	ipa_interrupt_suspend_clear_all(ipa->interrupt);
	}

	/* The next few functions coordinate stopping and starting the modem
	* network device transmit queue.
	*
	* Transmit can be running concurrent with power resume, and there's a
	* chance the resume completes before the transmit path stops the queue,
	* leaving the queue in a stopped state. The next two functions are used
	* to avoid this: ipa_power_modem_queue_stop() is used by ipa_start_xmit()
	* to conditionally stop the TX queue; and ipa_power_modem_queue_start()
	* is used by ipa_runtime_resume() to conditionally restart it.
	*
	* Two flags and a spinlock are used. If the queue is stopped, the STOPPED
	* power flag is set. And if the queue is started, the STARTED flag is set.
	* The queue is only started on resume if the STOPPED flag is set. And the
	* queue is only started in ipa_start_xmit() if the STARTED flag is not
	* set. As a result, the queue remains operational if the two activites
	* happen concurrently regardless of the order they complete. The spinlock
	* ensures the flag and TX queue operations are done atomically.
	*
	* The first function stops the modem netdev transmit queue, but only if
	* the STARTED flag is not set. That flag is cleared if it was set.
	* If the queue is stopped, the STOPPED flag is set. This is called only
	* from the power ->runtime_resume operation.
	*/
	void ipa_power_modem_queue_stop(struct ipa *ipa)
	{
	struct ipa_power *power = ipa->power;
	unsigned long flags;

	spin_lock_irqsave(&power->spinlock, flags);

	if (!__test_and_clear_bit(IPA_POWER_FLAG_STARTED, power->flags)) {
	netif_stop_queue(ipa->modem_netdev);
	__set_bit(IPA_POWER_FLAG_STOPPED, power->flags);
	}

	spin_unlock_irqrestore(&power->spinlock, flags);
	}

	/* This function starts the modem netdev transmit queue, but only if the
	* STOPPED flag is set. That flag is cleared if it was set. If the queue
	* was restarted, the STARTED flag is set; this allows ipa_start_xmit()
	* to skip stopping the queue in the event of a race.
	*/
	void ipa_power_modem_queue_wake(struct ipa *ipa)
	{
	struct ipa_power *power = ipa->power;
	unsigned long flags;

	spin_lock_irqsave(&power->spinlock, flags);

	if (__test_and_clear_bit(IPA_POWER_FLAG_STOPPED, power->flags)) {
	__set_bit(IPA_POWER_FLAG_STARTED, power->flags);
	netif_wake_queue(ipa->modem_netdev);
	}

	spin_unlock_irqrestore(&power->spinlock, flags);
	}

	/* This function clears the STARTED flag once the TX queue is operating */
	void ipa_power_modem_queue_active(struct ipa *ipa)
	{
	clear_bit(IPA_POWER_FLAG_STARTED, ipa->power->flags);
	}

	static int ipa_power_retention_init(struct ipa_power *power)
	{
	struct qmp *qmp = qmp_get(power->dev);

	if (IS_ERR(qmp)) {
	if (PTR_ERR(qmp) == -EPROBE_DEFER)
	return -EPROBE_DEFER;

	/* We assume any other error means it's not defined/needed */
	qmp = NULL;
	}
	power->qmp = qmp;

	return 0;
	}

	static void ipa_power_retention_exit(struct ipa_power *power)
	{
	qmp_put(power->qmp);
	power->qmp = NULL;
	}

	/* Control register retention on power collapse */
	void ipa_power_retention(struct ipa *ipa, bool enable)
	{
	static const char fmt[] = "{ class: bcm, res: ipa_pc, val: %c }";
	struct ipa_power *power = ipa->power;
	char buf[36]; /* Exactly enough for fmt[]; size a multiple of 4 */
	int ret;

	if (!power->qmp)
	return; /* Not needed on this platform */

	(void)snprintf(buf, sizeof(buf), fmt, enable ? '1' : '0');

	ret = qmp_send(power->qmp, buf, sizeof(buf));
	if (ret)
	dev_err(power->dev, "error %d sending QMP %sable request\n",
	ret, enable ? "en" : "dis");
	}

	int ipa_power_setup(struct ipa *ipa)
	{
	int ret;

	ipa_interrupt_enable(ipa, IPA_IRQ_TX_SUSPEND);

	ret = device_init_wakeup(&ipa->pdev->dev, true);
	if (ret)
	ipa_interrupt_disable(ipa, IPA_IRQ_TX_SUSPEND);

	return ret;
	}

	void ipa_power_teardown(struct ipa *ipa)
	{
	(void)device_init_wakeup(&ipa->pdev->dev, false);
	ipa_interrupt_disable(ipa, IPA_IRQ_TX_SUSPEND);
	}

	/* Initialize IPA power management */
	struct ipa_power *
	ipa_power_init(struct device dev, const struct ipa_power_data data)
	{
	struct ipa_power *power;
	struct clk *clk;
	size_t size;
	int ret;

	clk = clk_get(dev, "core");
	if (IS_ERR(clk)) {
	dev_err_probe(dev, PTR_ERR(clk), "error getting core clock\n");

	return ERR_CAST(clk);
	}

	ret = clk_set_rate(clk, data->core_clock_rate);
	if (ret) {
	dev_err(dev, "error %d setting core clock rate to %u\n",
	ret, data->core_clock_rate);
	goto err_clk_put;
	}

	size = struct_size(power, interconnect, data->interconnect_count);
	power = kzalloc(size, GFP_KERNEL);
	if (!power) {
	ret = -ENOMEM;
	goto err_clk_put;
	}
	power->dev = dev;
	power->core = clk;
	spin_lock_init(&power->spinlock);
	power->interconnect_count = data->interconnect_count;

	ret = ipa_interconnect_init(power, data->interconnect_data);
	if (ret)
	goto err_kfree;

	ret = ipa_power_retention_init(power);
	if (ret)
	goto err_interconnect_exit;

	pm_runtime_set_autosuspend_delay(dev, IPA_AUTOSUSPEND_DELAY);
	pm_runtime_use_autosuspend(dev);
	pm_runtime_enable(dev);

	return power;

	err_interconnect_exit:
	ipa_interconnect_exit(power);
	err_kfree:
	kfree(power);
	err_clk_put:
	clk_put(clk);

	return ERR_PTR(ret);
	}

	/* Inverse of ipa_power_init() */
	void ipa_power_exit(struct ipa_power *power)
	{
	struct device *dev = power->dev;
	struct clk *clk = power->core;

	pm_runtime_disable(dev);
	pm_runtime_dont_use_autosuspend(dev);
	ipa_power_retention_exit(power);
	ipa_interconnect_exit(power);
	kfree(power);
	clk_put(clk);
	}

	const struct dev_pm_ops ipa_pm_ops = {
	.suspend = ipa_suspend,
	.resume = ipa_resume,
	.runtime_suspend = ipa_runtime_suspend,
	.runtime_resume = ipa_runtime_resume,
	};