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authorMichael Bestas <mkbestas@gmail.com>2020-04-18 17:12:06 +0300
committerMichael Bestas <mkbestas@gmail.com>2020-04-18 17:12:39 +0300
commitddfa99dce7571688697e965b992a35b3f01c1aba (patch)
tree83e4f6b862bf4752c73e09d7d60496be95a1eda4 /gps/utils/LocSharedLock.h
parent570a57c7abc1a0f0e48698821e0061dd2e807dc5 (diff)
parentea8aefcf657335910a97e158e1c4752db9b0a880 (diff)
sdm660-common: Import GPS HAL from LA.UM.8.2.r1-04300-sdm660.0
Change-Id: I5e93d71bc7df7bb46af8c4b9ff11e8302113cfa9
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+/* Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials provided
+ * with the distribution.
+ * * Neither the name of The Linux Foundation, nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+ * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+#ifndef __LOC_SHARED_LOCK__
+#define __LOC_SHARED_LOCK__
+
+#include <stddef.h>
+#ifndef FEATURE_EXTERNAL_AP
+#include <cutils/atomic.h>
+#endif /* FEATURE_EXTERNAL_AP */
+#include <pthread.h>
+
+#ifdef FEATURE_EXTERNAL_AP
+#include <atomic>
+
+inline int32_t android_atomic_inc(volatile int32_t *addr)
+{
+ volatile std::atomic_int_least32_t* a = (volatile std::atomic_int_least32_t*)addr;
+ return std::atomic_fetch_add_explicit(a, 1, std::memory_order_release);
+}
+
+inline int32_t android_atomic_dec(volatile int32_t *addr)
+{
+ volatile std::atomic_int_least32_t* a = (volatile std::atomic_int_least32_t*)addr;
+ return std::atomic_fetch_sub_explicit(a, 1, std::memory_order_release);
+}
+
+#endif /* FEATURE_EXTERNAL_AP */
+ // This is a utility created for use cases such that there are more than
+// one client who need to share the same lock, but it is not predictable
+// which of these clients is to last to go away. This shared lock deletes
+// itself when the last client calls its drop() method. To add a cient,
+// this share lock's share() method has to be called, so that the obj
+// can maintain an accurate client count.
+class LocSharedLock {
+ volatile int32_t mRef;
+ pthread_mutex_t mMutex;
+ inline ~LocSharedLock() { pthread_mutex_destroy(&mMutex); }
+public:
+ // first client to create this LockSharedLock
+ inline LocSharedLock() : mRef(1) { pthread_mutex_init(&mMutex, NULL); }
+ // following client(s) are to *share()* this lock created by the first client
+ inline LocSharedLock* share() { android_atomic_inc(&mRef); return this; }
+ // whe a client no longer needs this shared lock, drop() shall be called.
+ inline void drop() { if (1 == android_atomic_dec(&mRef)) delete this; }
+ // locking the lock to enter critical section
+ inline void lock() { pthread_mutex_lock(&mMutex); }
+ // unlocking the lock to leave the critical section
+ inline void unlock() { pthread_mutex_unlock(&mMutex); }
+};
+
+#endif //__LOC_SHARED_LOCK__