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

 // SPDX-License-Identifier: GPL-2.0

 /* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
  * Copyright (C) 2018-2021 Linaro Ltd.
  */

 #include <linux/refcount.h>
 #include <linux/mutex.h>
 #include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/interconnect.h>

 #include "ipa.h"
 #include "ipa_clock.h"
 #include "ipa_modem.h"
 #include "ipa_data.h"

 /**
  * DOC: IPA Clocking
  *
  * The "IPA Clock" manages both the IPA core clock and the interconnects
  * (buses) the IPA depends on as a single logical entity.  A reference count
  * is incremented by "get" operations and decremented by "put" operations.
  * Transitions of that count from 0 to 1 result in the clock and interconnects
  * being enabled, and transitions of the count from 1 to 0 cause them to be
  * disabled.  We currently operate the core clock at a fixed clock rate, and
  * all buses at a fixed average and peak bandwidth.  As more advanced IPA
  * features are enabled, we can make better use of clock and bus scaling.
  *
  * An IPA clock reference must be held for any access to IPA hardware.
  */

 /**
  * struct ipa_interconnect - IPA interconnect information
  * @path:		Interconnect path
  * @average_bandwidth:	Average interconnect bandwidth (KB/second)
  * @peak_bandwidth:	Peak interconnect bandwidth (KB/second)
  */
 struct ipa_interconnect {
 	struct icc_path *path;
 	u32 average_bandwidth;
 	u32 peak_bandwidth;
 };

 /**
  * struct ipa_clock - IPA clocking information
  * @count:		Clocking reference count
  * @mutex:		Protects clock enable/disable
  * @core:		IPA core clock
  * @interconnect_count:	Number of elements in interconnect[]
  * @interconnect:	Interconnect array
  */
 struct ipa_clock {
 	refcount_t count;
 	struct mutex mutex; /* protects clock enable/disable */
 	struct clk *core;
 	u32 interconnect_count;
 	struct ipa_interconnect *interconnect;
 };

 static int ipa_interconnect_init_one(struct device *dev,
 				     struct ipa_interconnect *interconnect,
 				     const struct ipa_interconnect_data *data)
 {
 	struct icc_path *path;

 	path = of_icc_get(dev, data->name);
 	if (IS_ERR(path)) {
 		int ret = PTR_ERR(path);

 		dev_err_probe(dev, ret, "error getting %s interconnect\n",
 			      data->name);

 		return ret;
 	}

 	interconnect->path = path;
 	interconnect->average_bandwidth = data->average_bandwidth;
 	interconnect->peak_bandwidth = data->peak_bandwidth;

 	return 0;
 }

 static void ipa_interconnect_exit_one(struct ipa_interconnect *interconnect)
 {
 	icc_put(interconnect->path);
 	memset(interconnect, 0, sizeof(*interconnect));
 }

 /* Initialize interconnects required for IPA operation */
 static int ipa_interconnect_init(struct ipa_clock *clock, struct device *dev,
 				 const struct ipa_interconnect_data *data)
 {
 	struct ipa_interconnect *interconnect;
 	u32 count;
 	int ret;

 	count = clock->interconnect_count;
 	interconnect = kcalloc(count, sizeof(*interconnect), GFP_KERNEL);
 	if (!interconnect)
 		return -ENOMEM;
 	clock->interconnect = interconnect;

 	while (count--) {
 		ret = ipa_interconnect_init_one(dev, interconnect, data++);
 		if (ret)
 			goto out_unwind;
 		interconnect++;
 	}

 	return 0;

 out_unwind:
 	while (interconnect-- > clock->interconnect)
 		ipa_interconnect_exit_one(interconnect);
 	kfree(clock->interconnect);
 	clock->interconnect = NULL;

 	return ret;
 }

 /* Inverse of ipa_interconnect_init() */
 static void ipa_interconnect_exit(struct ipa_clock *clock)
 {
 	struct ipa_interconnect *interconnect;

 	interconnect = clock->interconnect + clock->interconnect_count;
 	while (interconnect-- > clock->interconnect)
 		ipa_interconnect_exit_one(interconnect);
 	kfree(clock->interconnect);
 	clock->interconnect = NULL;
 }

 /* Currently we only use one bandwidth level, so just "enable" interconnects */
 static int ipa_interconnect_enable(struct ipa *ipa)
 {
 	struct ipa_interconnect *interconnect;
 	struct ipa_clock *clock = ipa->clock;
 	int ret;
 	u32 i;

 	interconnect = clock->interconnect;
 	for (i = 0; i < clock->interconnect_count; i++) {
 		ret = icc_set_bw(interconnect->path,
 				 interconnect->average_bandwidth,
 				 interconnect->peak_bandwidth);
 		if (ret)
 			goto out_unwind;
 		interconnect++;
 	}

 	return 0;

 out_unwind:
 	while (interconnect-- > clock->interconnect)
 		(void)icc_set_bw(interconnect->path, 0, 0);

 	return ret;
 }

 /* To disable an interconnect, we just its bandwidth to 0 */
 static void ipa_interconnect_disable(struct ipa *ipa)
 {
 	struct ipa_interconnect *interconnect;
 	struct ipa_clock *clock = ipa->clock;
 	int result = 0;
 	u32 count;
 	int ret;

 	count = clock->interconnect_count;
 	interconnect = clock->interconnect + count;
 	while (count--) {
 		interconnect--;
 		ret = icc_set_bw(interconnect->path, 0, 0);
 		if (ret && !result)
 			result = ret;
 	}

 	if (result)
 		dev_err(&ipa->pdev->dev,
 			"error %d disabling IPA interconnects\n", ret);
 }

 /* Turn on IPA clocks, including interconnects */
 static int ipa_clock_enable(struct ipa *ipa)
 {
 	int ret;

 	ret = ipa_interconnect_enable(ipa);
 	if (ret)
 		return ret;

 	ret = clk_prepare_enable(ipa->clock->core);
 	if (ret)
 		ipa_interconnect_disable(ipa);

 	return ret;
 }

 /* Inverse of ipa_clock_enable() */
 static void ipa_clock_disable(struct ipa *ipa)
 {
 	clk_disable_unprepare(ipa->clock->core);
 	ipa_interconnect_disable(ipa);
 }

 /* Get an IPA clock reference, but only if the reference count is
  * already non-zero.  Returns true if the additional reference was
  * added successfully, or false otherwise.
  */
 bool ipa_clock_get_additional(struct ipa *ipa)
 {
 	return refcount_inc_not_zero(&ipa->clock->count);
 }

 /* Get an IPA clock reference.  If the reference count is non-zero, it is
  * incremented and return is immediate.  Otherwise it is checked again
  * under protection of the mutex, and if appropriate the IPA clock
  * is enabled.
  *
  * Incrementing the reference count is intentionally deferred until
  * after the clock is running and endpoints are resumed.
  */
 void ipa_clock_get(struct ipa *ipa)
 {
 	struct ipa_clock *clock = ipa->clock;
 	int ret;

 	/* If the clock is running, just bump the reference count */
 	if (ipa_clock_get_additional(ipa))
 		return;

 	/* Otherwise get the mutex and check again */
 	mutex_lock(&clock->mutex);

 	/* A reference might have been added before we got the mutex. */
 	if (ipa_clock_get_additional(ipa))
 		goto out_mutex_unlock;

 	ret = ipa_clock_enable(ipa);
 	if (ret) {
 		dev_err(&ipa->pdev->dev, "error %d enabling IPA clock\n", ret);
 		goto out_mutex_unlock;
 	}

 	refcount_set(&clock->count, 1);

 out_mutex_unlock:
 	mutex_unlock(&clock->mutex);
 }

 /* Attempt to remove an IPA clock reference.  If this represents the
  * last reference, disable the IPA clock under protection of the mutex.
  */
 void ipa_clock_put(struct ipa *ipa)
 {
 	struct ipa_clock *clock = ipa->clock;

 	/* If this is not the last reference there's nothing more to do */
 	if (!refcount_dec_and_mutex_lock(&clock->count, &clock->mutex))
 		return;

 	ipa_clock_disable(ipa);

 	mutex_unlock(&clock->mutex);
 }

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

 /* Initialize IPA clocking */
 struct ipa_clock *
 ipa_clock_init(struct device *dev, const struct ipa_clock_data *data)
 {
 	struct ipa_clock *clock;
 	struct clk *clk;
 	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;
 	}

 	clock = kzalloc(sizeof(*clock), GFP_KERNEL);
 	if (!clock) {
 		ret = -ENOMEM;
 		goto err_clk_put;
 	}
 	clock->core = clk;
 	clock->interconnect_count = data->interconnect_count;

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

 	mutex_init(&clock->mutex);
 	refcount_set(&clock->count, 0);

 	return clock;

 err_kfree:
 	kfree(clock);
 err_clk_put:
 	clk_put(clk);

 	return ERR_PTR(ret);
 }

 /* Inverse of ipa_clock_init() */
 void ipa_clock_exit(struct ipa_clock *clock)
 {
 	struct clk *clk = clock->core;

 	WARN_ON(refcount_read(&clock->count) != 0);
 	mutex_destroy(&clock->mutex);
 	ipa_interconnect_exit(clock);
 	kfree(clock);
 	clk_put(clk);
 }
	// SPDX-License-Identifier: GPL-2.0

	/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
	* Copyright (C) 2018-2021 Linaro Ltd.
	*/

	#include <linux/refcount.h>
	#include <linux/mutex.h>
	#include <linux/clk.h>
	#include <linux/device.h>
	#include <linux/interconnect.h>

	#include "ipa.h"
	#include "ipa_clock.h"
	#include "ipa_modem.h"
	#include "ipa_data.h"

	/**
	* DOC: IPA Clocking
	*
	* The "IPA Clock" manages both the IPA core clock and the interconnects
	* (buses) the IPA depends on as a single logical entity. A reference count
	* is incremented by "get" operations and decremented by "put" operations.
	* Transitions of that count from 0 to 1 result in the clock and interconnects
	* being enabled, and transitions of the count from 1 to 0 cause them to be
	* disabled. We currently operate the core clock at a fixed clock rate, and
	* all buses at a fixed average and peak bandwidth. As more advanced IPA
	* features are enabled, we can make better use of clock and bus scaling.
	*
	* An IPA clock reference must be held for any access to IPA hardware.
	*/

	/**
	* struct ipa_interconnect - IPA interconnect information
	* @path: Interconnect path
	* @average_bandwidth: Average interconnect bandwidth (KB/second)
	* @peak_bandwidth: Peak interconnect bandwidth (KB/second)
	*/
	struct ipa_interconnect {
	struct icc_path *path;
	u32 average_bandwidth;
	u32 peak_bandwidth;
	};

	/**
	* struct ipa_clock - IPA clocking information
	* @count: Clocking reference count
	* @mutex: Protects clock enable/disable
	* @core: IPA core clock
	* @interconnect_count: Number of elements in interconnect[]
	* @interconnect: Interconnect array
	*/
	struct ipa_clock {
	refcount_t count;
	struct mutex mutex; /* protects clock enable/disable */
	struct clk *core;
	u32 interconnect_count;
	struct ipa_interconnect *interconnect;
	};

	static int ipa_interconnect_init_one(struct device *dev,
	struct ipa_interconnect *interconnect,
	const struct ipa_interconnect_data *data)
	{
	struct icc_path *path;

	path = of_icc_get(dev, data->name);
	if (IS_ERR(path)) {
	int ret = PTR_ERR(path);

	dev_err_probe(dev, ret, "error getting %s interconnect\n",
	data->name);

	return ret;
	}

	interconnect->path = path;
	interconnect->average_bandwidth = data->average_bandwidth;
	interconnect->peak_bandwidth = data->peak_bandwidth;

	return 0;
	}

	static void ipa_interconnect_exit_one(struct ipa_interconnect *interconnect)
	{
	icc_put(interconnect->path);
	memset(interconnect, 0, sizeof(*interconnect));
	}

	/* Initialize interconnects required for IPA operation */
	static int ipa_interconnect_init(struct ipa_clock clock, struct device dev,
	const struct ipa_interconnect_data *data)
	{
	struct ipa_interconnect *interconnect;
	u32 count;
	int ret;

	count = clock->interconnect_count;
	interconnect = kcalloc(count, sizeof(*interconnect), GFP_KERNEL);
	if (!interconnect)
	return -ENOMEM;
	clock->interconnect = interconnect;

	while (count--) {
	ret = ipa_interconnect_init_one(dev, interconnect, data++);
	if (ret)
	goto out_unwind;
	interconnect++;
	}

	return 0;

	out_unwind:
	while (interconnect-- > clock->interconnect)
	ipa_interconnect_exit_one(interconnect);
	kfree(clock->interconnect);
	clock->interconnect = NULL;

	return ret;
	}

	/* Inverse of ipa_interconnect_init() */
	static void ipa_interconnect_exit(struct ipa_clock *clock)
	{
	struct ipa_interconnect *interconnect;

	interconnect = clock->interconnect + clock->interconnect_count;
	while (interconnect-- > clock->interconnect)
	ipa_interconnect_exit_one(interconnect);
	kfree(clock->interconnect);
	clock->interconnect = NULL;
	}

	/* Currently we only use one bandwidth level, so just "enable" interconnects */
	static int ipa_interconnect_enable(struct ipa *ipa)
	{
	struct ipa_interconnect *interconnect;
	struct ipa_clock *clock = ipa->clock;
	int ret;
	u32 i;

	interconnect = clock->interconnect;
	for (i = 0; i < clock->interconnect_count; i++) {
	ret = icc_set_bw(interconnect->path,
	interconnect->average_bandwidth,
	interconnect->peak_bandwidth);
	if (ret)
	goto out_unwind;
	interconnect++;
	}

	return 0;

	out_unwind:
	while (interconnect-- > clock->interconnect)
	(void)icc_set_bw(interconnect->path, 0, 0);

	return ret;
	}

	/* To disable an interconnect, we just its bandwidth to 0 */
	static void ipa_interconnect_disable(struct ipa *ipa)
	{
	struct ipa_interconnect *interconnect;
	struct ipa_clock *clock = ipa->clock;
	int result = 0;
	u32 count;
	int ret;

	count = clock->interconnect_count;
	interconnect = clock->interconnect + count;
	while (count--) {
	interconnect--;
	ret = icc_set_bw(interconnect->path, 0, 0);
	if (ret && !result)
	result = ret;
	}

	if (result)
	dev_err(&ipa->pdev->dev,
	"error %d disabling IPA interconnects\n", ret);
	}

	/* Turn on IPA clocks, including interconnects */
	static int ipa_clock_enable(struct ipa *ipa)
	{
	int ret;

	ret = ipa_interconnect_enable(ipa);
	if (ret)
	return ret;

	ret = clk_prepare_enable(ipa->clock->core);
	if (ret)
	ipa_interconnect_disable(ipa);

	return ret;
	}

	/* Inverse of ipa_clock_enable() */
	static void ipa_clock_disable(struct ipa *ipa)
	{
	clk_disable_unprepare(ipa->clock->core);
	ipa_interconnect_disable(ipa);
	}

	/* Get an IPA clock reference, but only if the reference count is
	* already non-zero. Returns true if the additional reference was
	* added successfully, or false otherwise.
	*/
	bool ipa_clock_get_additional(struct ipa *ipa)
	{
	return refcount_inc_not_zero(&ipa->clock->count);
	}

	/* Get an IPA clock reference. If the reference count is non-zero, it is
	* incremented and return is immediate. Otherwise it is checked again
	* under protection of the mutex, and if appropriate the IPA clock
	* is enabled.
	*
	* Incrementing the reference count is intentionally deferred until
	* after the clock is running and endpoints are resumed.
	*/
	void ipa_clock_get(struct ipa *ipa)
	{
	struct ipa_clock *clock = ipa->clock;
	int ret;

	/* If the clock is running, just bump the reference count */
	if (ipa_clock_get_additional(ipa))
	return;

	/* Otherwise get the mutex and check again */
	mutex_lock(&clock->mutex);

	/* A reference might have been added before we got the mutex. */
	if (ipa_clock_get_additional(ipa))
	goto out_mutex_unlock;

	ret = ipa_clock_enable(ipa);
	if (ret) {
	dev_err(&ipa->pdev->dev, "error %d enabling IPA clock\n", ret);
	goto out_mutex_unlock;
	}

	refcount_set(&clock->count, 1);

	out_mutex_unlock:
	mutex_unlock(&clock->mutex);
	}

	/* Attempt to remove an IPA clock reference. If this represents the
	* last reference, disable the IPA clock under protection of the mutex.
	*/
	void ipa_clock_put(struct ipa *ipa)
	{
	struct ipa_clock *clock = ipa->clock;

	/* If this is not the last reference there's nothing more to do */
	if (!refcount_dec_and_mutex_lock(&clock->count, &clock->mutex))
	return;

	ipa_clock_disable(ipa);

	mutex_unlock(&clock->mutex);
	}

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

	/* Initialize IPA clocking */
	struct ipa_clock *
	ipa_clock_init(struct device dev, const struct ipa_clock_data data)
	{
	struct ipa_clock *clock;
	struct clk *clk;
	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;
	}

	clock = kzalloc(sizeof(*clock), GFP_KERNEL);
	if (!clock) {
	ret = -ENOMEM;
	goto err_clk_put;
	}
	clock->core = clk;
	clock->interconnect_count = data->interconnect_count;

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

	mutex_init(&clock->mutex);
	refcount_set(&clock->count, 0);

	return clock;

	err_kfree:
	kfree(clock);
	err_clk_put:
	clk_put(clk);

	return ERR_PTR(ret);
	}

	/* Inverse of ipa_clock_init() */
	void ipa_clock_exit(struct ipa_clock *clock)
	{
	struct clk *clk = clock->core;

	WARN_ON(refcount_read(&clock->count) != 0);
	mutex_destroy(&clock->mutex);
	ipa_interconnect_exit(clock);
	kfree(clock);
	clk_put(clk);
	}