1 files changed, 400 insertions, 109 deletions

diff --git a/drivers/hwspinlock/hwspinlock_core.c b/drivers/hwspinlock/hwspinlock_core.c
index 461a0d739d75..cc8e952a6772 100644
--- a/drivers/hwspinlock/hwspinlock_core.c
+++ b/drivers/hwspinlock/hwspinlock_core.c
@@ -1,22 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Hardware spinlock framework
  *
  * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com
  *
  * Contact: Ohad Ben-Cohen <ohad@wizery.com>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published
- * by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #define pr_fmt(fmt)    "%s: " fmt, __func__
 
+#include <linux/delay.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/spinlock.h>
@@ -27,9 +20,13 @@
 #include <linux/hwspinlock.h>
 #include <linux/pm_runtime.h>
 #include <linux/mutex.h>
+#include <linux/of.h>
 
 #include "hwspinlock_internal.h"
 
+/* retry delay used in atomic context */
+#define HWSPINLOCK_RETRY_DELAY_US	100
+
 /* radix tree tags */
 #define HWSPINLOCK_UNUSED	(0) /* tags an hwspinlock as unused */
 
@@ -70,10 +67,16 @@ static DEFINE_MUTEX(hwspinlock_tree_lock);
  * This function attempts to lock an hwspinlock, and will immediately
  * fail if the hwspinlock is already taken.
  *
- * Upon a successful return from this function, preemption (and possibly
- * interrupts) is disabled, so the caller must not sleep, and is advised to
- * release the hwspinlock as soon as possible. This is required in order to
- * minimize remote cores polling on the hardware interconnect.
+ * Caution: If the mode is HWLOCK_RAW, that means user must protect the routine
+ * of getting hardware lock with mutex or spinlock. Since in some scenarios,
+ * user need some time-consuming or sleepable operations under the hardware
+ * lock, they need one sleepable lock (like mutex) to protect the operations.
+ *
+ * If the mode is neither HWLOCK_IN_ATOMIC nor HWLOCK_RAW, upon a successful
+ * return from this function, preemption (and possibly interrupts) is disabled,
+ * so the caller must not sleep, and is advised to release the hwspinlock as
+ * soon as possible. This is required in order to minimize remote cores polling
+ * on the hardware interconnect.
  *
  * The user decides whether local interrupts are disabled or not, and if yes,
  * whether he wants their previous state to be saved. It is up to the user
@@ -81,16 +84,17 @@ static DEFINE_MUTEX(hwspinlock_tree_lock);
  * should decide between spin_trylock, spin_trylock_irq and
  * spin_trylock_irqsave.
  *
- * Returns 0 if we successfully locked the hwspinlock or -EBUSY if
+ * Returns: %0 if we successfully locked the hwspinlock or -EBUSY if
  * the hwspinlock was already taken.
+ *
  * This function will never sleep.
  */
 int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
 {
 	int ret;
 
-	BUG_ON(!hwlock);
-	BUG_ON(!flags && mode == HWLOCK_IRQSTATE);
+	if (WARN_ON(!hwlock || (!flags && mode == HWLOCK_IRQSTATE)))
+		return -EINVAL;
 
 	/*
 	 * This spin_lock{_irq, _irqsave} serves three purposes:
@@ -105,12 +109,21 @@ int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
 	 *    problems with hwspinlock usage (e.g. scheduler checks like
 	 *    'scheduling while atomic' etc.)
 	 */
-	if (mode == HWLOCK_IRQSTATE)
+	switch (mode) {
+	case HWLOCK_IRQSTATE:
 		ret = spin_trylock_irqsave(&hwlock->lock, *flags);
-	else if (mode == HWLOCK_IRQ)
+		break;
+	case HWLOCK_IRQ:
 		ret = spin_trylock_irq(&hwlock->lock);
-	else
+		break;
+	case HWLOCK_RAW:
+	case HWLOCK_IN_ATOMIC:
+		ret = 1;
+		break;
+	default:
 		ret = spin_trylock(&hwlock->lock);
+		break;
+	}
 
 	/* is lock already taken by another context on the local cpu ? */
 	if (!ret)
@@ -121,12 +134,21 @@ int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
 
 	/* if hwlock is already taken, undo spin_trylock_* and exit */
 	if (!ret) {
-		if (mode == HWLOCK_IRQSTATE)
+		switch (mode) {
+		case HWLOCK_IRQSTATE:
 			spin_unlock_irqrestore(&hwlock->lock, *flags);
-		else if (mode == HWLOCK_IRQ)
+			break;
+		case HWLOCK_IRQ:
 			spin_unlock_irq(&hwlock->lock);
-		else
+			break;
+		case HWLOCK_RAW:
+		case HWLOCK_IN_ATOMIC:
+			/* Nothing to do */
+			break;
+		default:
 			spin_unlock(&hwlock->lock);
+			break;
+		}
 
 		return -EBUSY;
 	}
@@ -150,7 +172,7 @@ EXPORT_SYMBOL_GPL(__hwspin_trylock);
 /**
  * __hwspin_lock_timeout() - lock an hwspinlock with timeout limit
  * @hwlock: the hwspinlock to be locked
- * @timeout: timeout value in msecs
+ * @to: timeout value in msecs
  * @mode: mode which controls whether local interrupts are disabled or not
  * @flags: a pointer to where the caller's interrupt state will be saved at (if
  *         requested)
@@ -159,26 +181,36 @@ EXPORT_SYMBOL_GPL(__hwspin_trylock);
  * is already taken, the function will busy loop waiting for it to
  * be released, but give up after @timeout msecs have elapsed.
  *
- * Upon a successful return from this function, preemption is disabled
- * (and possibly local interrupts, too), so the caller must not sleep,
- * and is advised to release the hwspinlock as soon as possible.
- * This is required in order to minimize remote cores polling on the
- * hardware interconnect.
+ * Caution: If the mode is HWLOCK_RAW, that means user must protect the routine
+ * of getting hardware lock with mutex or spinlock. Since in some scenarios,
+ * user need some time-consuming or sleepable operations under the hardware
+ * lock, they need one sleepable lock (like mutex) to protect the operations.
+ *
+ * If the mode is HWLOCK_IN_ATOMIC (called from an atomic context) the timeout
+ * is handled with busy-waiting delays, hence shall not exceed few msecs.
+ *
+ * If the mode is neither HWLOCK_IN_ATOMIC nor HWLOCK_RAW, upon a successful
+ * return from this function, preemption (and possibly interrupts) is disabled,
+ * so the caller must not sleep, and is advised to release the hwspinlock as
+ * soon as possible. This is required in order to minimize remote cores polling
+ * on the hardware interconnect.
  *
  * The user decides whether local interrupts are disabled or not, and if yes,
  * whether he wants their previous state to be saved. It is up to the user
  * to choose the appropriate @mode of operation, exactly the same way users
  * should decide between spin_lock, spin_lock_irq and spin_lock_irqsave.
  *
- * Returns 0 when the @hwlock was successfully taken, and an appropriate
+ * Returns: %0 when the @hwlock was successfully taken, and an appropriate
  * error code otherwise (most notably -ETIMEDOUT if the @hwlock is still
- * busy after @timeout msecs). The function will never sleep.
+ * busy after @timeout msecs).
+ *
+ * The function will never sleep.
  */
 int __hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int to,
 					int mode, unsigned long *flags)
 {
 	int ret;
-	unsigned long expire;
+	unsigned long expire, atomic_delay = 0;
 
 	expire = msecs_to_jiffies(to) + jiffies;
 
@@ -192,8 +224,15 @@ int __hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int to,
 		 * The lock is already taken, let's check if the user wants
 		 * us to try again
 		 */
-		if (time_is_before_eq_jiffies(expire))
-			return -ETIMEDOUT;
+		if (mode == HWLOCK_IN_ATOMIC) {
+			udelay(HWSPINLOCK_RETRY_DELAY_US);
+			atomic_delay += HWSPINLOCK_RETRY_DELAY_US;
+			if (atomic_delay > to * 1000)
+				return -ETIMEDOUT;
+		} else {
+			if (time_is_before_eq_jiffies(expire))
+				return -ETIMEDOUT;
+		}
 
 		/*
 		 * Allow platform-specific relax handlers to prevent
@@ -228,8 +267,8 @@ EXPORT_SYMBOL_GPL(__hwspin_lock_timeout);
  */
 void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
 {
-	BUG_ON(!hwlock);
-	BUG_ON(!flags && mode == HWLOCK_IRQSTATE);
+	if (WARN_ON(!hwlock || (!flags && mode == HWLOCK_IRQSTATE)))
+		return;
 
 	/*
 	 * We must make sure that memory operations (both reads and writes),
@@ -248,15 +287,169 @@ void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
 	hwlock->bank->ops->unlock(hwlock);
 
 	/* Undo the spin_trylock{_irq, _irqsave} called while locking */
-	if (mode == HWLOCK_IRQSTATE)
+	switch (mode) {
+	case HWLOCK_IRQSTATE:
 		spin_unlock_irqrestore(&hwlock->lock, *flags);
-	else if (mode == HWLOCK_IRQ)
+		break;
+	case HWLOCK_IRQ:
 		spin_unlock_irq(&hwlock->lock);
-	else
+		break;
+	case HWLOCK_RAW:
+	case HWLOCK_IN_ATOMIC:
+		/* Nothing to do */
+		break;
+	default:
 		spin_unlock(&hwlock->lock);
+		break;
+	}
 }
 EXPORT_SYMBOL_GPL(__hwspin_unlock);
 
+/**
+ * hwspin_lock_bust() - bust a specific hwspinlock
+ * @hwlock: a previously-acquired hwspinlock which we want to bust
+ * @id: identifier of the remote lock holder, if applicable
+ *
+ * This function will bust a hwspinlock that was previously acquired as
+ * long as the current owner of the lock matches the id given by the caller.
+ *
+ * Context: Process context.
+ *
+ * Returns: 0 on success, or -EINVAL if the hwspinlock does not exist, or
+ * the bust operation fails, and -EOPNOTSUPP if the bust operation is not
+ * defined for the hwspinlock.
+ */
+int hwspin_lock_bust(struct hwspinlock *hwlock, unsigned int id)
+{
+	if (WARN_ON(!hwlock))
+		return -EINVAL;
+
+	if (!hwlock->bank->ops->bust) {
+		pr_err("bust operation not defined\n");
+		return -EOPNOTSUPP;
+	}
+
+	return hwlock->bank->ops->bust(hwlock, id);
+}
+EXPORT_SYMBOL_GPL(hwspin_lock_bust);
+
+/**
+ * of_hwspin_lock_simple_xlate - translate hwlock_spec to return a lock id
+ * @hwlock_spec: hwlock specifier as found in the device tree
+ *
+ * This is a simple translation function, suitable for hwspinlock platform
+ * drivers that only has a lock specifier length of 1.
+ *
+ * Returns: a relative index of the lock within a specified bank on success,
+ * or -EINVAL on invalid specifier cell count.
+ */
+static inline int
+of_hwspin_lock_simple_xlate(const struct of_phandle_args *hwlock_spec)
+{
+	if (WARN_ON(hwlock_spec->args_count != 1))
+		return -EINVAL;
+
+	return hwlock_spec->args[0];
+}
+
+/**
+ * of_hwspin_lock_get_id() - get lock id for an OF phandle-based specific lock
+ * @np: device node from which to request the specific hwlock
+ * @index: index of the hwlock in the list of values
+ *
+ * This function provides a means for DT users of the hwspinlock module to
+ * get the global lock id of a specific hwspinlock using the phandle of the
+ * hwspinlock device, so that it can be requested using the normal
+ * hwspin_lock_request_specific() API.
+ *
+ * Returns: the global lock id number on success, -EPROBE_DEFER if the
+ * hwspinlock device is not yet registered, -EINVAL on invalid args
+ * specifier value or an appropriate error as returned from the OF parsing
+ * of the DT client node.
+ */
+int of_hwspin_lock_get_id(struct device_node *np, int index)
+{
+	struct of_phandle_args args;
+	struct hwspinlock *hwlock;
+	struct radix_tree_iter iter;
+	void **slot;
+	int id;
+	int ret;
+
+	ret = of_parse_phandle_with_args(np, "hwlocks", "#hwlock-cells", index,
+					 &args);
+	if (ret)
+		return ret;
+
+	if (!of_device_is_available(args.np)) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	/* Find the hwspinlock device: we need its base_id */
+	ret = -EPROBE_DEFER;
+	rcu_read_lock();
+	radix_tree_for_each_slot(slot, &hwspinlock_tree, &iter, 0) {
+		hwlock = radix_tree_deref_slot(slot);
+		if (unlikely(!hwlock))
+			continue;
+		if (radix_tree_deref_retry(hwlock)) {
+			slot = radix_tree_iter_retry(&iter);
+			continue;
+		}
+
+		if (device_match_of_node(hwlock->bank->dev, args.np)) {
+			ret = 0;
+			break;
+		}
+	}
+	rcu_read_unlock();
+	if (ret < 0)
+		goto out;
+
+	id = of_hwspin_lock_simple_xlate(&args);
+	if (id < 0 || id >= hwlock->bank->num_locks) {
+		ret = -EINVAL;
+		goto out;
+	}
+	id += hwlock->bank->base_id;
+
+out:
+	of_node_put(args.np);
+	return ret ? ret : id;
+}
+EXPORT_SYMBOL_GPL(of_hwspin_lock_get_id);
+
+/**
+ * of_hwspin_lock_get_id_byname() - get lock id for an specified hwlock name
+ * @np: device node from which to request the specific hwlock
+ * @name: hwlock name
+ *
+ * This function provides a means for DT users of the hwspinlock module to
+ * get the global lock id of a specific hwspinlock using the specified name of
+ * the hwspinlock device, so that it can be requested using the normal
+ * hwspin_lock_request_specific() API.
+ *
+ * Returns: the global lock id number on success, -EPROBE_DEFER if the
+ * hwspinlock device is not yet registered, -EINVAL on invalid args
+ * specifier value or an appropriate error as returned from the OF parsing
+ * of the DT client node.
+ */
+int of_hwspin_lock_get_id_byname(struct device_node *np, const char *name)
+{
+	int index;
+
+	if (!name)
+		return -EINVAL;
+
+	index = of_property_match_string(np, "hwlock-names", name);
+	if (index < 0)
+		return index;
+
+	return of_hwspin_lock_get_id(np, index);
+}
+EXPORT_SYMBOL_GPL(of_hwspin_lock_get_id_byname);
+
 static int hwspin_lock_register_single(struct hwspinlock *hwlock, int id)
 {
 	struct hwspinlock *tmp;
@@ -320,7 +513,7 @@ out:
  *
  * Should be called from a process context (might sleep)
  *
- * Returns 0 on success, or an appropriate error code on failure
+ * Returns: %0 on success, or an appropriate error code on failure
  */
 int hwspin_lock_register(struct hwspinlock_device *bank, struct device *dev,
 		const struct hwspinlock_ops *ops, int base_id, int num_locks)
@@ -368,7 +561,7 @@ EXPORT_SYMBOL_GPL(hwspin_lock_register);
  *
  * Should be called from a process context (might sleep)
  *
- * Returns 0 on success, or an appropriate error code on failure
+ * Returns: %0 on success, or an appropriate error code on failure
  */
 int hwspin_lock_unregister(struct hwspinlock_device *bank)
 {
@@ -390,14 +583,97 @@ int hwspin_lock_unregister(struct hwspinlock_device *bank)
 }
 EXPORT_SYMBOL_GPL(hwspin_lock_unregister);
 
+static void devm_hwspin_lock_unreg(struct device *dev, void *res)
+{
+	hwspin_lock_unregister(*(struct hwspinlock_device **)res);
+}
+
+static int devm_hwspin_lock_device_match(struct device *dev, void *res,
+					 void *data)
+{
+	struct hwspinlock_device **bank = res;
+
+	if (WARN_ON(!bank || !*bank))
+		return 0;
+
+	return *bank == data;
+}
+
+/**
+ * devm_hwspin_lock_unregister() - unregister an hw spinlock device for
+ *				   a managed device
+ * @dev: the backing device
+ * @bank: the hwspinlock device, which usually provides numerous hw locks
+ *
+ * This function should be called from the underlying platform-specific
+ * implementation, to unregister an existing (and unused) hwspinlock.
+ *
+ * Should be called from a process context (might sleep)
+ *
+ * Returns: %0 on success, or an appropriate error code on failure
+ */
+int devm_hwspin_lock_unregister(struct device *dev,
+				struct hwspinlock_device *bank)
+{
+	int ret;
+
+	ret = devres_release(dev, devm_hwspin_lock_unreg,
+			     devm_hwspin_lock_device_match, bank);
+	WARN_ON(ret);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devm_hwspin_lock_unregister);
+
+/**
+ * devm_hwspin_lock_register() - register a new hw spinlock device for
+ *				 a managed device
+ * @dev: the backing device
+ * @bank: the hwspinlock device, which usually provides numerous hw locks
+ * @ops: hwspinlock handlers for this device
+ * @base_id: id of the first hardware spinlock in this bank
+ * @num_locks: number of hwspinlocks provided by this device
+ *
+ * This function should be called from the underlying platform-specific
+ * implementation, to register a new hwspinlock device instance.
+ *
+ * Should be called from a process context (might sleep)
+ *
+ * Returns: %0 on success, or an appropriate error code on failure
+ */
+int devm_hwspin_lock_register(struct device *dev,
+			      struct hwspinlock_device *bank,
+			      const struct hwspinlock_ops *ops,
+			      int base_id, int num_locks)
+{
+	struct hwspinlock_device **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_hwspin_lock_unreg, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = hwspin_lock_register(bank, dev, ops, base_id, num_locks);
+	if (!ret) {
+		*ptr = bank;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devm_hwspin_lock_register);
+
 /**
  * __hwspin_lock_request() - tag an hwspinlock as used and power it up
+ * @hwlock: the target hwspinlock
  *
  * This is an internal function that prepares an hwspinlock instance
  * before it is given to the user. The function assumes that
  * hwspinlock_tree_lock is taken.
  *
- * Returns 0 or positive to indicate success, and a negative value to
+ * Returns: %0 or positive to indicate success, and a negative value to
  * indicate an error (with the appropriate error code)
  */
 static int __hwspin_lock_request(struct hwspinlock *hwlock)
@@ -414,13 +690,15 @@ static int __hwspin_lock_request(struct hwspinlock *hwlock)
 
 	/* notify PM core that power is now needed */
 	ret = pm_runtime_get_sync(dev);
-	if (ret < 0) {
+	if (ret < 0 && ret != -EACCES) {
 		dev_err(dev, "%s: can't power on device\n", __func__);
 		pm_runtime_put_noidle(dev);
 		module_put(dev->driver->owner);
 		return ret;
 	}
 
+	ret = 0;
+
 	/* mark hwspinlock as used, should not fail */
 	tmp = radix_tree_tag_clear(&hwspinlock_tree, hwlock_to_id(hwlock),
 							HWSPINLOCK_UNUSED);
@@ -432,66 +710,6 @@ static int __hwspin_lock_request(struct hwspinlock *hwlock)
 }
 
 /**
- * hwspin_lock_get_id() - retrieve id number of a given hwspinlock
- * @hwlock: a valid hwspinlock instance
- *
- * Returns the id number of a given @hwlock, or -EINVAL if @hwlock is invalid.
- */
-int hwspin_lock_get_id(struct hwspinlock *hwlock)
-{
-	if (!hwlock) {
-		pr_err("invalid hwlock\n");
-		return -EINVAL;
-	}
-
-	return hwlock_to_id(hwlock);
-}
-EXPORT_SYMBOL_GPL(hwspin_lock_get_id);
-
-/**
- * hwspin_lock_request() - request an hwspinlock
- *
- * This function should be called by users of the hwspinlock device,
- * in order to dynamically assign them an unused hwspinlock.
- * Usually the user of this lock will then have to communicate the lock's id
- * to the remote core before it can be used for synchronization (to get the
- * id of a given hwlock, use hwspin_lock_get_id()).
- *
- * Should be called from a process context (might sleep)
- *
- * Returns the address of the assigned hwspinlock, or NULL on error
- */
-struct hwspinlock *hwspin_lock_request(void)
-{
-	struct hwspinlock *hwlock;
-	int ret;
-
-	mutex_lock(&hwspinlock_tree_lock);
-
-	/* look for an unused lock */
-	ret = radix_tree_gang_lookup_tag(&hwspinlock_tree, (void **)&hwlock,
-						0, 1, HWSPINLOCK_UNUSED);
-	if (ret == 0) {
-		pr_warn("a free hwspinlock is not available\n");
-		hwlock = NULL;
-		goto out;
-	}
-
-	/* sanity check that should never fail */
-	WARN_ON(ret > 1);
-
-	/* mark as used and power up */
-	ret = __hwspin_lock_request(hwlock);
-	if (ret < 0)
-		hwlock = NULL;
-
-out:
-	mutex_unlock(&hwspinlock_tree_lock);
-	return hwlock;
-}
-EXPORT_SYMBOL_GPL(hwspin_lock_request);
-
-/**
  * hwspin_lock_request_specific() - request for a specific hwspinlock
  * @id: index of the specific hwspinlock that is requested
  *
@@ -502,7 +720,7 @@ EXPORT_SYMBOL_GPL(hwspin_lock_request);
  *
  * Should be called from a process context (might sleep)
  *
- * Returns the address of the assigned hwspinlock, or NULL on error
+ * Returns: the address of the assigned hwspinlock, or %NULL on error
  */
 struct hwspinlock *hwspin_lock_request_specific(unsigned int id)
 {
@@ -546,11 +764,11 @@ EXPORT_SYMBOL_GPL(hwspin_lock_request_specific);
  *
  * This function mark @hwlock as free again.
  * Should only be called with an @hwlock that was retrieved from
- * an earlier call to omap_hwspin_lock_request{_specific}.
+ * an earlier call to hwspin_lock_request{_specific}.
  *
  * Should be called from a process context (might sleep)
  *
- * Returns 0 on success, or an appropriate error code on failure
+ * Returns: %0 on success, or an appropriate error code on failure
  */
 int hwspin_lock_free(struct hwspinlock *hwlock)
 {
@@ -577,9 +795,7 @@ int hwspin_lock_free(struct hwspinlock *hwlock)
 	}
 
 	/* notify the underlying device that power is not needed */
-	ret = pm_runtime_put(dev);
-	if (ret < 0)
-		goto out;
+	pm_runtime_put(dev);
 
 	/* mark this hwspinlock as available */
 	tmp = radix_tree_tag_set(&hwspinlock_tree, hwlock_to_id(hwlock),
@@ -596,6 +812,81 @@ out:
 }
 EXPORT_SYMBOL_GPL(hwspin_lock_free);
 
-MODULE_LICENSE("GPL v2");
+static int devm_hwspin_lock_match(struct device *dev, void *res, void *data)
+{
+	struct hwspinlock **hwlock = res;
+
+	if (WARN_ON(!hwlock || !*hwlock))
+		return 0;
+
+	return *hwlock == data;
+}
+
+static void devm_hwspin_lock_release(struct device *dev, void *res)
+{
+	hwspin_lock_free(*(struct hwspinlock **)res);
+}
+
+/**
+ * devm_hwspin_lock_free() - free a specific hwspinlock for a managed device
+ * @dev: the device to free the specific hwspinlock
+ * @hwlock: the specific hwspinlock to free
+ *
+ * This function mark @hwlock as free again.
+ * Should only be called with an @hwlock that was retrieved from
+ * an earlier call to hwspin_lock_request{_specific}.
+ *
+ * Should be called from a process context (might sleep)
+ *
+ * Returns: %0 on success, or an appropriate error code on failure
+ */
+int devm_hwspin_lock_free(struct device *dev, struct hwspinlock *hwlock)
+{
+	int ret;
+
+	ret = devres_release(dev, devm_hwspin_lock_release,
+			     devm_hwspin_lock_match, hwlock);
+	WARN_ON(ret);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devm_hwspin_lock_free);
+
+/**
+ * devm_hwspin_lock_request_specific() - request for a specific hwspinlock for
+ *					 a managed device
+ * @dev: the device to request the specific hwspinlock
+ * @id: index of the specific hwspinlock that is requested
+ *
+ * This function should be called by users of the hwspinlock module,
+ * in order to assign them a specific hwspinlock.
+ * Usually early board code will be calling this function in order to
+ * reserve specific hwspinlock ids for predefined purposes.
+ *
+ * Should be called from a process context (might sleep)
+ *
+ * Returns: the address of the assigned hwspinlock, or %NULL on error
+ */
+struct hwspinlock *devm_hwspin_lock_request_specific(struct device *dev,
+						     unsigned int id)
+{
+	struct hwspinlock **ptr, *hwlock;
+
+	ptr = devres_alloc(devm_hwspin_lock_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	hwlock = hwspin_lock_request_specific(id);
+	if (hwlock) {
+		*ptr = hwlock;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return hwlock;
+}
+EXPORT_SYMBOL_GPL(devm_hwspin_lock_request_specific);
+
 MODULE_DESCRIPTION("Hardware spinlock interface");
 MODULE_AUTHOR("Ohad Ben-Cohen <ohad@wizery.com>");