staging: sync: Add synchronization framework
Sync is a framework for synchronization between multiple
drivers. Sync implementations can take advantage of hardware
synchronization built into devices like GPUs.
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Erik Gilling <konkers@android.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Clark <robclark@gmail.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: dri-devel@lists.freedesktop.org
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Erik Gilling <konkers@android.com>
[jstultz: Added commit message, moved to staging, squished minor fix in]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/android/sync.h b/drivers/staging/android/sync.h
new file mode 100644
index 0000000..388acd1
--- /dev/null
+++ b/drivers/staging/android/sync.h
@@ -0,0 +1,314 @@
+/*
+ * include/linux/sync.h
+ *
+ * Copyright (C) 2012 Google, Inc.
+ *
+ * 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_SYNC_H
+#define _LINUX_SYNC_H
+
+#include <linux/types.h>
+#ifdef __KERNEL__
+
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/wait.h>
+
+struct sync_timeline;
+struct sync_pt;
+struct sync_fence;
+
+/**
+ * struct sync_timeline_ops - sync object implementation ops
+ * @driver_name: name of the implentation
+ * @dup: duplicate a sync_pt
+ * @has_signaled: returns:
+ * 1 if pt has signaled
+ * 0 if pt has not signaled
+ * <0 on error
+ * @compare: returns:
+ * 1 if b will signal before a
+ * 0 if a and b will signal at the same time
+ * -1 if a will signabl before b
+ * @free_pt: called before sync_pt is freed
+ * @release_obj: called before sync_timeline is freed
+ */
+struct sync_timeline_ops {
+ const char *driver_name;
+
+ /* required */
+ struct sync_pt *(*dup)(struct sync_pt *pt);
+
+ /* required */
+ int (*has_signaled)(struct sync_pt *pt);
+
+ /* required */
+ int (*compare)(struct sync_pt *a, struct sync_pt *b);
+
+ /* optional */
+ void (*free_pt)(struct sync_pt *sync_pt);
+
+ /* optional */
+ void (*release_obj)(struct sync_timeline *sync_timeline);
+};
+
+/**
+ * struct sync_timeline - sync object
+ * @ops: ops that define the implementaiton of the sync_timeline
+ * @name: name of the sync_timeline. Useful for debugging
+ * @destoryed: set when sync_timeline is destroyed
+ * @child_list_head: list of children sync_pts for this sync_timeline
+ * @child_list_lock: lock protecting @child_list_head, destroyed, and
+ * sync_pt.status
+ * @active_list_head: list of active (unsignaled/errored) sync_pts
+ */
+struct sync_timeline {
+ const struct sync_timeline_ops *ops;
+ char name[32];
+
+ /* protected by child_list_lock */
+ bool destroyed;
+
+ struct list_head child_list_head;
+ spinlock_t child_list_lock;
+
+ struct list_head active_list_head;
+ spinlock_t active_list_lock;
+};
+
+/**
+ * struct sync_pt - sync point
+ * @parent: sync_timeline to which this sync_pt belongs
+ * @child_list: membership in sync_timeline.child_list_head
+ * @active_list: membership in sync_timeline.active_list_head
+ * @fence: sync_fence to which the sync_pt belongs
+ * @pt_list: membership in sync_fence.pt_list_head
+ * @status: 1: signaled, 0:active, <0: error
+ */
+struct sync_pt {
+ struct sync_timeline *parent;
+ struct list_head child_list;
+
+ struct list_head active_list;
+
+ struct sync_fence *fence;
+ struct list_head pt_list;
+
+ /* protected by parent->active_list_lock */
+ int status;
+};
+
+/**
+ * struct sync_fence - sync fence
+ * @file: file representing this fence
+ * @name: name of sync_fence. Useful for debugging
+ * @pt_list_head: list of sync_pts in ths fence. immutable once fence
+ * is created
+ * @waiter_list_head: list of asynchronous waiters on this fence
+ * @waiter_list_lock: lock protecting @waiter_list_head and @status
+ * @status: 1: signaled, 0:active, <0: error
+ *
+ * @wq: wait queue for fence signaling
+ */
+struct sync_fence {
+ struct file *file;
+ char name[32];
+
+ /* this list is immutable once the fence is created */
+ struct list_head pt_list_head;
+
+ struct list_head waiter_list_head;
+ spinlock_t waiter_list_lock; /* also protects status */
+ int status;
+
+ wait_queue_head_t wq;
+};
+
+/**
+ * struct sync_fence_waiter - metadata for asynchronous waiter on a fence
+ * @waiter_list: membership in sync_fence.waiter_list_head
+ * @callback: function pointer to call when fence signals
+ * @callback_data: pointer to pass to @callback
+ */
+struct sync_fence_waiter {
+ struct list_head waiter_list;
+
+ void (*callback)(struct sync_fence *fence, void *data);
+ void *callback_data;
+};
+
+/*
+ * API for sync_timeline implementers
+ */
+
+/**
+ * sync_timeline_create() - creates a sync object
+ * @ops: specifies the implemention ops for the object
+ * @size: size to allocate for this obj
+ * @name: sync_timeline name
+ *
+ * Creates a new sync_timeline which will use the implemetation specified by
+ * @ops. @size bytes will be allocated allowing for implemntation specific
+ * data to be kept after the generic sync_timeline stuct.
+ */
+struct sync_timeline *sync_timeline_create(const struct sync_timeline_ops *ops,
+ int size, const char *name);
+
+/**
+ * sync_timeline_destory() - destorys a sync object
+ * @obj: sync_timeline to destroy
+ *
+ * A sync implemntation should call this when the @obj is going away
+ * (i.e. module unload.) @obj won't actually be freed until all its childern
+ * sync_pts are freed.
+ */
+void sync_timeline_destroy(struct sync_timeline *obj);
+
+/**
+ * sync_timeline_signal() - signal a status change on a sync_timeline
+ * @obj: sync_timeline to signal
+ *
+ * A sync implemntation should call this any time one of it's sync_pts
+ * has signaled or has an error condition.
+ */
+void sync_timeline_signal(struct sync_timeline *obj);
+
+/**
+ * sync_pt_create() - creates a sync pt
+ * @parent: sync_pt's parent sync_timeline
+ * @size: size to allocate for this pt
+ *
+ * Creates a new sync_pt as a chiled of @parent. @size bytes will be
+ * allocated allowing for implemntation specific data to be kept after
+ * the generic sync_timeline struct.
+ */
+struct sync_pt *sync_pt_create(struct sync_timeline *parent, int size);
+
+/**
+ * sync_pt_free() - frees a sync pt
+ * @pt: sync_pt to free
+ *
+ * This should only be called on sync_pts which have been created but
+ * not added to a fence.
+ */
+void sync_pt_free(struct sync_pt *pt);
+
+/**
+ * sync_fence_create() - creates a sync fence
+ * @name: name of fence to create
+ * @pt: sync_pt to add to the fence
+ *
+ * Creates a fence containg @pt. Once this is called, the fence takes
+ * ownership of @pt.
+ */
+struct sync_fence *sync_fence_create(const char *name, struct sync_pt *pt);
+
+/*
+ * API for sync_fence consumers
+ */
+
+/**
+ * sync_fence_merge() - merge two fences
+ * @name: name of new fence
+ * @a: fence a
+ * @b: fence b
+ *
+ * Creates a new fence which contains copies of all the sync_pts in both
+ * @a and @b. @a and @b remain valid, independent fences.
+ */
+struct sync_fence *sync_fence_merge(const char *name,
+ struct sync_fence *a, struct sync_fence *b);
+
+/**
+ * sync_fence_fdget() - get a fence from an fd
+ * @fd: fd referencing a fence
+ *
+ * Ensures @fd references a valid fence, increments the refcount of the backing
+ * file, and returns the fence.
+ */
+struct sync_fence *sync_fence_fdget(int fd);
+
+/**
+ * sync_fence_put() - puts a refernnce of a sync fence
+ * @fence: fence to put
+ *
+ * Puts a reference on @fence. If this is the last reference, the fence and
+ * all it's sync_pts will be freed
+ */
+void sync_fence_put(struct sync_fence *fence);
+
+/**
+ * sync_fence_install() - installs a fence into a file descriptor
+ * @fence: fence to instal
+ * @fd: file descriptor in which to install the fence
+ *
+ * Installs @fence into @fd. @fd's should be acquired through get_unused_fd().
+ */
+void sync_fence_install(struct sync_fence *fence, int fd);
+
+/**
+ * sync_fence_wait_async() - registers and async wait on the fence
+ * @fence: fence to wait on
+ * @callback: callback
+ * @callback_data data to pass to the callback
+ *
+ * Returns 1 if @fence has already signaled.
+ *
+ * Registers a callback to be called when @fence signals or has an error
+ */
+int sync_fence_wait_async(struct sync_fence *fence,
+ void (*callback)(struct sync_fence *, void *data),
+ void *callback_data);
+
+/**
+ * sync_fence_wait() - wait on fence
+ * @fence: fence to wait on
+ * @tiemout: timeout in ms
+ *
+ * Wait for @fence to be signaled or have an error. Waits indefintly
+ * if @timeout = 0
+ */
+int sync_fence_wait(struct sync_fence *fence, long timeout);
+
+/* useful for sync driver's debug print handlers */
+const char *sync_status_str(int status);
+
+#endif /* __KERNEL__ */
+
+/**
+ * struct sync_merge_data - data passed to merge ioctl
+ * @fd2: file descriptor of second fence
+ * @name: name of new fence
+ * @fence: returns the fd of the new fence to userspace
+ */
+struct sync_merge_data {
+ __s32 fd2; /* fd of second fence */
+ char name[32]; /* name of new fence */
+ __s32 fence; /* fd on newly created fence */
+};
+
+#define SYNC_IOC_MAGIC '>'
+
+/**
+ * DOC: SYNC_IOC_WAIT - wait for a fence to signal
+ *
+ * pass timeout in milliseconds.
+ */
+#define SYNC_IOC_WAIT _IOW(SYNC_IOC_MAGIC, 0, __u32)
+
+/**
+ * DOC: SYNC_IOC_MERGE - merge two fences
+ *
+ * Takes a struct sync_merge_data. Creates a new fence containing copies of
+ * the sync_pts in both the calling fd and sync_merge_data.fd2. Returns the
+ * new fence's fd in sync_merge_data.fence
+ */
+#define SYNC_IOC_MERGE _IOWR(SYNC_IOC_MAGIC, 1, struct sync_merge_data)
+
+#endif /* _LINUX_SYNC_H */