Merge tag 'hwlock-v4.18' of git://github.com/andersson/remoteproc

Pull hwspinlock updates from Bjorn Andersson:
 "In addition to migrating the files to use SPDX license headers this
  introduces the ability for clients to operate a hwlock without the
  framework taking any additional locks"

* tag 'hwlock-v4.18' of git://github.com/andersson/remoteproc:
  hwspinlock/u8500: Switch to SPDX license identifier
  hwspinlock: sprd: Switch to SPDX license identifier
  hwspinlock/sirf: Switch to SPDX license identifier
  hwspinlock: qcom: Switch to SPDX license identifier
  hwspinlock/omap: Switch to SPDX license identifier
  hwspinlock/core: Switch to SPDX license identifier
  hwspinlock: Introduce one new mode for hwspinlock
  hwspinlock: Convert to use 'switch' statement

drivers/hwspinlock/Kconfig

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Generic HWSPINLOCK framework
 #

drivers/hwspinlock/hwspinlock_core.c

@@ -1,18 +1,10 @@
+// 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__
@@ -71,10 +63,16 @@ 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 not 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
@@ -106,12 +104,20 @@ 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:
+		ret = 1;
+		break;
+	default:
 		ret = spin_trylock(&hwlock->lock);
+		break;
+	}
 
 	/* is lock already taken by another context on the local cpu ? */
 	if (!ret)
@@ -122,12 +128,20 @@ 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:
+			/* Nothing to do */
+			break;
+		default:
 			spin_unlock(&hwlock->lock);
+			break;
+		}
 
 		return -EBUSY;
 	}
@@ -160,9 +174,14 @@ 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.
+ * 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 not HWLOCK_RAW, 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.
  *
@@ -249,12 +268,20 @@ 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:
+		/* Nothing to do */
+		break;
+	default:
 		spin_unlock(&hwlock->lock);
+		break;
+	}
 }
 EXPORT_SYMBOL_GPL(__hwspin_unlock);
 

drivers/hwspinlock/hwspinlock_internal.h

@@ -1,18 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Hardware spinlocks internal header
  *
  * 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.
  */
 
 #ifndef __HWSPINLOCK_HWSPINLOCK_H

drivers/hwspinlock/omap_hwspinlock.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * OMAP hardware spinlock driver
  *
@@ -6,15 +7,6 @@
  * Contact: Simon Que <sque@ti.com>
  *          Hari Kanigeri <h-kanigeri2@ti.com>
  *          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.
  */
 
 #include <linux/kernel.h>

drivers/hwspinlock/qcom_hwspinlock.c

@@ -1,15 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2013, The Linux Foundation. All rights reserved.
  * Copyright (c) 2015, Sony Mobile Communications AB
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * 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.
  */
 
 #include <linux/hwspinlock.h>

drivers/hwspinlock/sirf_hwspinlock.c

@@ -1,9 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * SIRF hardware spinlock driver
  *
  * Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company.
- *
- * Licensed under GPLv2.
  */
 
 #include <linux/kernel.h>

drivers/hwspinlock/sprd_hwspinlock.c

@@ -1,15 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Spreadtrum hardware spinlock driver
  * Copyright (C) 2017 Spreadtrum  - http://www.spreadtrum.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.
  */
 
 #include <linux/bitops.h>

drivers/hwspinlock/u8500_hsem.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * u8500 HWSEM driver
  *
@@ -10,15 +11,6 @@
  *   Simon Que <sque@ti.com>
  *   Hari Kanigeri <h-kanigeri2@ti.com>
  *   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.
  */
 
 #include <linux/module.h>

include/linux/hwspinlock.h

@@ -1,18 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Hardware spinlock public header
  *
  * 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.
  */
 
 #ifndef __LINUX_HWSPINLOCK_H
@@ -24,6 +16,7 @@
 /* hwspinlock mode argument */
 #define HWLOCK_IRQSTATE	0x01	/* Disable interrupts, save state */
 #define HWLOCK_IRQ	0x02	/* Disable interrupts, don't save state */
+#define HWLOCK_RAW	0x03
 
 struct device;
 struct device_node;
@@ -175,6 +168,25 @@ static inline int hwspin_trylock_irq(struct hwspinlock *hwlock)
 	return __hwspin_trylock(hwlock, HWLOCK_IRQ, NULL);
 }
 
+/**
+ * hwspin_trylock_raw() - attempt to lock a specific hwspinlock
+ * @hwlock: an hwspinlock which we want to trylock
+ *
+ * This function attempts to lock an hwspinlock, and will immediately fail
+ * if the hwspinlock is already taken.
+ *
+ * Caution: User must protect the routine of getting hardware lock with mutex
+ * or spinlock to avoid dead-lock, that will let user can do some time-consuming
+ * or sleepable operations under the hardware lock.
+ *
+ * Returns 0 if we successfully locked the hwspinlock, -EBUSY if
+ * the hwspinlock was already taken, and -EINVAL if @hwlock is invalid.
+ */
+static inline int hwspin_trylock_raw(struct hwspinlock *hwlock)
+{
+	return __hwspin_trylock(hwlock, HWLOCK_RAW, NULL);
+}
+
 /**
  * hwspin_trylock() - attempt to lock a specific hwspinlock
  * @hwlock: an hwspinlock which we want to trylock
@@ -242,6 +254,29 @@ int hwspin_lock_timeout_irq(struct hwspinlock *hwlock, unsigned int to)
 	return __hwspin_lock_timeout(hwlock, to, HWLOCK_IRQ, NULL);
 }
 
+/**
+ * hwspin_lock_timeout_raw() - lock an hwspinlock with timeout limit
+ * @hwlock: the hwspinlock to be locked
+ * @to: timeout value in msecs
+ *
+ * This function locks the underlying @hwlock. If the @hwlock
+ * is already taken, the function will busy loop waiting for it to
+ * be released, but give up when @timeout msecs have elapsed.
+ *
+ * Caution: User must protect the routine of getting hardware lock with mutex
+ * or spinlock to avoid dead-lock, that will let user can do some time-consuming
+ * or sleepable operations under the hardware lock.
+ *
+ * Returns 0 when the @hwlock was successfully taken, and an appropriate
+ * error code otherwise (most notably an -ETIMEDOUT if the @hwlock is still
+ * busy after @timeout msecs). The function will never sleep.
+ */
+static inline
+int hwspin_lock_timeout_raw(struct hwspinlock *hwlock, unsigned int to)
+{
+	return __hwspin_lock_timeout(hwlock, to, HWLOCK_RAW, NULL);
+}
+
 /**
  * hwspin_lock_timeout() - lock an hwspinlock with timeout limit
  * @hwlock: the hwspinlock to be locked
@@ -301,6 +336,21 @@ static inline void hwspin_unlock_irq(struct hwspinlock *hwlock)
 	__hwspin_unlock(hwlock, HWLOCK_IRQ, NULL);
 }
 
+/**
+ * hwspin_unlock_raw() - unlock hwspinlock
+ * @hwlock: a previously-acquired hwspinlock which we want to unlock
+ *
+ * This function will unlock a specific hwspinlock.
+ *
+ * @hwlock must be already locked (e.g. by hwspin_trylock()) before calling
+ * this function: it is a bug to call unlock on a @hwlock that is already
+ * unlocked.
+ */
+static inline void hwspin_unlock_raw(struct hwspinlock *hwlock)
+{
+	__hwspin_unlock(hwlock, HWLOCK_RAW, NULL);
+}
+
 /**
  * hwspin_unlock() - unlock hwspinlock
  * @hwlock: a previously-acquired hwspinlock which we want to unlock