Merge tag 'drm-fixes-5.3-2019-07-24' of git://people.freedesktop.org/~agd5f/linux...

[linux-2.6-microblaze.git] / include / linux / hwspinlock.h

diff --git a/include/linux/hwspinlock.h b/include/linux/hwspinlock.h
index 0afe693..bfe7c1f 100644 (file)
--- 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;
@@ -222,6 +223,23 @@ static inline int hwspin_trylock_raw(struct hwspinlock *hwlock)
        return __hwspin_trylock(hwlock, HWLOCK_RAW, NULL);
 }
 
+/**
+ * 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
@@ -312,6 +330,28 @@ int hwspin_lock_timeout_raw(struct hwspinlock *hwlock, unsigned int to)
        return __hwspin_lock_timeout(hwlock, to, HWLOCK_RAW, NULL);
 }
 
+/**
+ * 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
@@ -386,6 +426,21 @@ static inline void hwspin_unlock_raw(struct hwspinlock *hwlock)
        __hwspin_unlock(hwlock, HWLOCK_RAW, NULL);
 }
 
+/**
+ * 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