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Diffstat (limited to 'include/linux/hwspinlock.h')
-rw-r--r--include/linux/hwspinlock.h61
1 files changed, 58 insertions, 3 deletions
diff --git a/include/linux/hwspinlock.h b/include/linux/hwspinlock.h
index 0afe693be5f4..bfe7c1f1ac6d 100644
--- a/include/linux/hwspinlock.h
+++ b/include/linux/hwspinlock.h
@@ -14,9 +14,10 @@
#include <linux/sched.h>
/* 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
+#define HWLOCK_IRQSTATE 0x01 /* Disable interrupts, save state */
+#define HWLOCK_IRQ 0x02 /* Disable interrupts, don't save state */
+#define HWLOCK_RAW 0x03
+#define HWLOCK_IN_ATOMIC 0x04 /* Called while in atomic context */
struct device;
struct device_node;
@@ -223,6 +224,23 @@ static inline int hwspin_trylock_raw(struct hwspinlock *hwlock)
}
/**
+ * hwspin_trylock_in_atomic() - 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.
+ *
+ * This function shall be called only from an atomic context.
+ *
+ * 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_in_atomic(struct hwspinlock *hwlock)
+{
+ return __hwspin_trylock(hwlock, HWLOCK_IN_ATOMIC, NULL);
+}
+
+/**
* hwspin_trylock() - attempt to lock a specific hwspinlock
* @hwlock: an hwspinlock which we want to trylock
*
@@ -313,6 +331,28 @@ int hwspin_lock_timeout_raw(struct hwspinlock *hwlock, unsigned int to)
}
/**
+ * hwspin_lock_timeout_in_atomic() - 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.
+ *
+ * This function shall be called only from an atomic context and the timeout
+ * value shall not exceed a few msecs.
+ *
+ * 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_in_atomic(struct hwspinlock *hwlock, unsigned int to)
+{
+ return __hwspin_lock_timeout(hwlock, to, HWLOCK_IN_ATOMIC, NULL);
+}
+
+/**
* hwspin_lock_timeout() - lock an hwspinlock with timeout limit
* @hwlock: the hwspinlock to be locked
* @to: timeout value in msecs
@@ -387,6 +427,21 @@ static inline void hwspin_unlock_raw(struct hwspinlock *hwlock)
}
/**
+ * hwspin_unlock_in_atomic() - 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_in_atomic(struct hwspinlock *hwlock)
+{
+ __hwspin_unlock(hwlock, HWLOCK_IN_ATOMIC, NULL);
+}
+
+/**
* hwspin_unlock() - unlock hwspinlock
* @hwlock: a previously-acquired hwspinlock which we want to unlock
*