hwspinlock updates for v4.18

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. -----BEGIN PGP SIGNATURE----- iQJPBAABCAA5FiEEBd4DzF816k8JZtUlCx85Pw2ZrcUFAlsevMIbHGJqb3JuLmFu ZGVyc3NvbkBsaW5hcm8ub3JnAAoJEAsfOT8Nma3FqjgQAKWiDEoEw75RZnfmRAVB Ot8TgeUoj6CodjV0pe3fLYBYLKzJbEBiC8VfjFKeq9JwndPsGaCXqcnrKegl11pd /supYYzsAWT4YUZFsq0Y00mnNWKHLVL2VkKh4yPD+GaRuBDITKaurBnv3tB19ccG aeG5eS2bIhMhcaRaPVSRYlb34Zz8PssvlYefToUiNCuBI33D45fRSvvn5z3o5xAh ZL0qEBVG8BviPIPMwlp5w1PIC8Rz+eyZRmaH+fV5lewUqh32hzf4ynAIr0aDYug7 tzFeSPqjxpvzRgZtocsJ2NqTm3jMEyzHL9X+Rt31ryN4flTROkCiWg4xDONvac7E fAq924WhvYqe2flNJjUR6azxjO0RsTx78LiAxZir43tvSjqdm3RTPgWOlCTdzP4u O5lDAm7c1QZISlKAXJewRccuUxg2XVdYa2tTBQalBqq9Ys1ZiMeWQ4UUNzvEIBji vlj2KguG5CgPrThhk/S11JCvG7Ti5frljebVasyF5nLX78bXPfTaBpPNre+kL6Ee 4AylueOFeT5+Ft8a7quokzvBGUmlwYPq6jPAAL4TrU39SLIWxXRv3qDczBRe0j9G Xh6L8GVrUIEWxJz04OxtsgG/N3zNujjUTy/G3A3AZgM7Ijneu0xNKAjXNHfD2XNu pH2+HeF8vKQNB89gZJkF90XW =KYHF -----END PGP SIGNATURE----- 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
2018-06-11 12:09:19 -07:00 · 2018-06-11 12:09:19 -07:00 · 6f75edeadd
--- a/drivers/hwspinlock/Kconfig
+++ b/drivers/hwspinlock/Kconfig
@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Generic HWSPINLOCK framework
 #
--- a/drivers/hwspinlock/hwspinlock_core.c
+++ b/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);

--- a/drivers/hwspinlock/hwspinlock_internal.h
+++ b/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
--- a/drivers/hwspinlock/omap_hwspinlock.c
+++ b/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>
--- a/drivers/hwspinlock/qcom_hwspinlock.c
+++ b/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>
--- a/drivers/hwspinlock/sirf_hwspinlock.c
+++ b/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>
--- a/drivers/hwspinlock/sprd_hwspinlock.c
+++ b/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>
--- a/drivers/hwspinlock/u8500_hsem.c
+++ b/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>
--- a/include/linux/hwspinlock.h
+++ b/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