Merge tag 'driver-core-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here's the big driver-core pull request for 3.17-rc1.

  Largest thing in here is the dma-buf rework and fence code, that
  touched many different subsystems so it was agreed it should go
  through this tree to handle merge issues.  There's also some firmware
  loading updates, as well as tests added, and a few other tiny changes,
  the changelog has the details.

  All have been in linux-next for a long time"

* tag 'driver-core-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (32 commits)
  ARM: imx: Remove references to platform_bus in mxc code
  firmware loader: Fix _request_firmware_load() return val for fw load abort
  platform: Remove most references to platform_bus device
  test: add firmware_class loader test
  doc: fix minor typos in firmware_class README
  staging: android: Cleanup style issues
  Documentation: devres: Sort managed interfaces
  Documentation: devres: Add devm_kmalloc() et al
  fs: debugfs: remove trailing whitespace
  kernfs: kernel-doc warning fix
  debugfs: Fix corrupted loop in debugfs_remove_recursive
  stable_kernel_rules: Add pointer to netdev-FAQ for network patches
  driver core: platform: add device binding path 'driver_override'
  driver core/platform: remove unused implicit padding in platform_object
  firmware loader: inform direct failure when udev loader is disabled
  firmware: replace ALIGN(PAGE_SIZE) by PAGE_ALIGN
  firmware: read firmware size using i_size_read()
  firmware loader: allow disabling of udev as firmware loader
  reservation: add suppport for read-only access using rcu
  reservation: update api and add some helpers
  ...

Conflicts:
	drivers/base/platform.c

8 files changed, 591 insertions, 13 deletions

diff --git a/include/linux/component.h b/include/linux/component.h
index 68870182ca1e..c00dcc302611 100644
--- a/include/linux/component.h
+++ b/include/linux/component.h
@@ -29,4 +29,11 @@ void component_master_del(struct device *,
 int component_master_add_child(struct master *master,
 	int (*compare)(struct device *, void *), void *compare_data);
 
+struct component_match;
+
+int component_master_add_with_match(struct device *,
+	const struct component_master_ops *, struct component_match *);
+void component_match_add(struct device *, struct component_match **,
+	int (*compare)(struct device *, void *), void *compare_data);
+
 #endif
diff --git a/include/linux/device.h b/include/linux/device.h
index af424acd393d..921fa0a74df6 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -631,8 +631,6 @@ extern unsigned long devm_get_free_pages(struct device *dev,
 extern void devm_free_pages(struct device *dev, unsigned long addr);
 
 void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res);
-void __iomem *devm_request_and_ioremap(struct device *dev,
-			struct resource *res);
 
 /* allows to add/remove a custom action to devres stack */
 int devm_add_action(struct device *dev, void (*action)(void *), void *data);
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index f886985a28b2..694e1fe1c4b4 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -30,6 +30,8 @@
 #include <linux/list.h>
 #include <linux/dma-mapping.h>
 #include <linux/fs.h>
+#include <linux/fence.h>
+#include <linux/wait.h>
 
 struct device;
 struct dma_buf;
@@ -115,6 +117,7 @@ struct dma_buf_ops {
  * @exp_name: name of the exporter; useful for debugging.
  * @list_node: node for dma_buf accounting and debugging.
  * @priv: exporter specific private data for this buffer object.
+ * @resv: reservation object linked to this dma-buf
  */
 struct dma_buf {
 	size_t size;
@@ -128,6 +131,17 @@ struct dma_buf {
 	const char *exp_name;
 	struct list_head list_node;
 	void *priv;
+	struct reservation_object *resv;
+
+	/* poll support */
+	wait_queue_head_t poll;
+
+	struct dma_buf_poll_cb_t {
+		struct fence_cb cb;
+		wait_queue_head_t *poll;
+
+		unsigned long active;
+	} cb_excl, cb_shared;
 };
 
 /**
@@ -168,10 +182,11 @@ void dma_buf_detach(struct dma_buf *dmabuf,
 				struct dma_buf_attachment *dmabuf_attach);
 
 struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
-			       size_t size, int flags, const char *);
+			       size_t size, int flags, const char *,
+			       struct reservation_object *);
 
-#define dma_buf_export(priv, ops, size, flags)	\
-	dma_buf_export_named(priv, ops, size, flags, KBUILD_MODNAME)
+#define dma_buf_export(priv, ops, size, flags, resv)	\
+	dma_buf_export_named(priv, ops, size, flags, KBUILD_MODNAME, resv)
 
 int dma_buf_fd(struct dma_buf *dmabuf, int flags);
 struct dma_buf *dma_buf_get(int fd);
diff --git a/include/linux/fence.h b/include/linux/fence.h
new file mode 100644
index 000000000000..d174585b874b
--- /dev/null
+++ b/include/linux/fence.h
@@ -0,0 +1,360 @@
+/*
+ * Fence mechanism for dma-buf to allow for asynchronous dma access
+ *
+ * Copyright (C) 2012 Canonical Ltd
+ * Copyright (C) 2012 Texas Instruments
+ *
+ * Authors:
+ * Rob Clark <robdclark@gmail.com>
+ * Maarten Lankhorst <maarten.lankhorst@canonical.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_FENCE_H
+#define __LINUX_FENCE_H
+
+#include <linux/err.h>
+#include <linux/wait.h>
+#include <linux/list.h>
+#include <linux/bitops.h>
+#include <linux/kref.h>
+#include <linux/sched.h>
+#include <linux/printk.h>
+#include <linux/rcupdate.h>
+
+struct fence;
+struct fence_ops;
+struct fence_cb;
+
+/**
+ * struct fence - software synchronization primitive
+ * @refcount: refcount for this fence
+ * @ops: fence_ops associated with this fence
+ * @rcu: used for releasing fence with kfree_rcu
+ * @cb_list: list of all callbacks to call
+ * @lock: spin_lock_irqsave used for locking
+ * @context: execution context this fence belongs to, returned by
+ *           fence_context_alloc()
+ * @seqno: the sequence number of this fence inside the execution context,
+ * can be compared to decide which fence would be signaled later.
+ * @flags: A mask of FENCE_FLAG_* defined below
+ * @timestamp: Timestamp when the fence was signaled.
+ * @status: Optional, only valid if < 0, must be set before calling
+ * fence_signal, indicates that the fence has completed with an error.
+ *
+ * the flags member must be manipulated and read using the appropriate
+ * atomic ops (bit_*), so taking the spinlock will not be needed most
+ * of the time.
+ *
+ * FENCE_FLAG_SIGNALED_BIT - fence is already signaled
+ * FENCE_FLAG_ENABLE_SIGNAL_BIT - enable_signaling might have been called*
+ * FENCE_FLAG_USER_BITS - start of the unused bits, can be used by the
+ * implementer of the fence for its own purposes. Can be used in different
+ * ways by different fence implementers, so do not rely on this.
+ *
+ * *) Since atomic bitops are used, this is not guaranteed to be the case.
+ * Particularly, if the bit was set, but fence_signal was called right
+ * before this bit was set, it would have been able to set the
+ * FENCE_FLAG_SIGNALED_BIT, before enable_signaling was called.
+ * Adding a check for FENCE_FLAG_SIGNALED_BIT after setting
+ * FENCE_FLAG_ENABLE_SIGNAL_BIT closes this race, and makes sure that
+ * after fence_signal was called, any enable_signaling call will have either
+ * been completed, or never called at all.
+ */
+struct fence {
+	struct kref refcount;
+	const struct fence_ops *ops;
+	struct rcu_head rcu;
+	struct list_head cb_list;
+	spinlock_t *lock;
+	unsigned context, seqno;
+	unsigned long flags;
+	ktime_t timestamp;
+	int status;
+};
+
+enum fence_flag_bits {
+	FENCE_FLAG_SIGNALED_BIT,
+	FENCE_FLAG_ENABLE_SIGNAL_BIT,
+	FENCE_FLAG_USER_BITS, /* must always be last member */
+};
+
+typedef void (*fence_func_t)(struct fence *fence, struct fence_cb *cb);
+
+/**
+ * struct fence_cb - callback for fence_add_callback
+ * @node: used by fence_add_callback to append this struct to fence::cb_list
+ * @func: fence_func_t to call
+ *
+ * This struct will be initialized by fence_add_callback, additional
+ * data can be passed along by embedding fence_cb in another struct.
+ */
+struct fence_cb {
+	struct list_head node;
+	fence_func_t func;
+};
+
+/**
+ * struct fence_ops - operations implemented for fence
+ * @get_driver_name: returns the driver name.
+ * @get_timeline_name: return the name of the context this fence belongs to.
+ * @enable_signaling: enable software signaling of fence.
+ * @signaled: [optional] peek whether the fence is signaled, can be null.
+ * @wait: custom wait implementation, or fence_default_wait.
+ * @release: [optional] called on destruction of fence, can be null
+ * @fill_driver_data: [optional] callback to fill in free-form debug info
+ * Returns amount of bytes filled, or -errno.
+ * @fence_value_str: [optional] fills in the value of the fence as a string
+ * @timeline_value_str: [optional] fills in the current value of the timeline
+ * as a string
+ *
+ * Notes on enable_signaling:
+ * For fence implementations that have the capability for hw->hw
+ * signaling, they can implement this op to enable the necessary
+ * irqs, or insert commands into cmdstream, etc.  This is called
+ * in the first wait() or add_callback() path to let the fence
+ * implementation know that there is another driver waiting on
+ * the signal (ie. hw->sw case).
+ *
+ * This function can be called called from atomic context, but not
+ * from irq context, so normal spinlocks can be used.
+ *
+ * A return value of false indicates the fence already passed,
+ * or some failure occured that made it impossible to enable
+ * signaling. True indicates succesful enabling.
+ *
+ * fence->status may be set in enable_signaling, but only when false is
+ * returned.
+ *
+ * Calling fence_signal before enable_signaling is called allows
+ * for a tiny race window in which enable_signaling is called during,
+ * before, or after fence_signal. To fight this, it is recommended
+ * that before enable_signaling returns true an extra reference is
+ * taken on the fence, to be released when the fence is signaled.
+ * This will mean fence_signal will still be called twice, but
+ * the second time will be a noop since it was already signaled.
+ *
+ * Notes on signaled:
+ * May set fence->status if returning true.
+ *
+ * Notes on wait:
+ * Must not be NULL, set to fence_default_wait for default implementation.
+ * the fence_default_wait implementation should work for any fence, as long
+ * as enable_signaling works correctly.
+ *
+ * Must return -ERESTARTSYS if the wait is intr = true and the wait was
+ * interrupted, and remaining jiffies if fence has signaled, or 0 if wait
+ * timed out. Can also return other error values on custom implementations,
+ * which should be treated as if the fence is signaled. For example a hardware
+ * lockup could be reported like that.
+ *
+ * Notes on release:
+ * Can be NULL, this function allows additional commands to run on
+ * destruction of the fence. Can be called from irq context.
+ * If pointer is set to NULL, kfree will get called instead.
+ */
+
+struct fence_ops {
+	const char * (*get_driver_name)(struct fence *fence);
+	const char * (*get_timeline_name)(struct fence *fence);
+	bool (*enable_signaling)(struct fence *fence);
+	bool (*signaled)(struct fence *fence);
+	signed long (*wait)(struct fence *fence, bool intr, signed long timeout);
+	void (*release)(struct fence *fence);
+
+	int (*fill_driver_data)(struct fence *fence, void *data, int size);
+	void (*fence_value_str)(struct fence *fence, char *str, int size);
+	void (*timeline_value_str)(struct fence *fence, char *str, int size);
+};
+
+void fence_init(struct fence *fence, const struct fence_ops *ops,
+		spinlock_t *lock, unsigned context, unsigned seqno);
+
+void fence_release(struct kref *kref);
+void fence_free(struct fence *fence);
+
+/**
+ * fence_get - increases refcount of the fence
+ * @fence:	[in]	fence to increase refcount of
+ *
+ * Returns the same fence, with refcount increased by 1.
+ */
+static inline struct fence *fence_get(struct fence *fence)
+{
+	if (fence)
+		kref_get(&fence->refcount);
+	return fence;
+}
+
+/**
+ * fence_get_rcu - get a fence from a reservation_object_list with rcu read lock
+ * @fence:	[in]	fence to increase refcount of
+ *
+ * Function returns NULL if no refcount could be obtained, or the fence.
+ */
+static inline struct fence *fence_get_rcu(struct fence *fence)
+{
+	if (kref_get_unless_zero(&fence->refcount))
+		return fence;
+	else
+		return NULL;
+}
+
+/**
+ * fence_put - decreases refcount of the fence
+ * @fence:	[in]	fence to reduce refcount of
+ */
+static inline void fence_put(struct fence *fence)
+{
+	if (fence)
+		kref_put(&fence->refcount, fence_release);
+}
+
+int fence_signal(struct fence *fence);
+int fence_signal_locked(struct fence *fence);
+signed long fence_default_wait(struct fence *fence, bool intr, signed long timeout);
+int fence_add_callback(struct fence *fence, struct fence_cb *cb,
+		       fence_func_t func);
+bool fence_remove_callback(struct fence *fence, struct fence_cb *cb);
+void fence_enable_sw_signaling(struct fence *fence);
+
+/**
+ * fence_is_signaled_locked - Return an indication if the fence is signaled yet.
+ * @fence:	[in]	the fence to check
+ *
+ * Returns true if the fence was already signaled, false if not. Since this
+ * function doesn't enable signaling, it is not guaranteed to ever return
+ * true if fence_add_callback, fence_wait or fence_enable_sw_signaling
+ * haven't been called before.
+ *
+ * This function requires fence->lock to be held.
+ */
+static inline bool
+fence_is_signaled_locked(struct fence *fence)
+{
+	if (test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+		return true;
+
+	if (fence->ops->signaled && fence->ops->signaled(fence)) {
+		fence_signal_locked(fence);
+		return true;
+	}
+
+	return false;
+}
+
+/**
+ * fence_is_signaled - Return an indication if the fence is signaled yet.
+ * @fence:	[in]	the fence to check
+ *
+ * Returns true if the fence was already signaled, false if not. Since this
+ * function doesn't enable signaling, it is not guaranteed to ever return
+ * true if fence_add_callback, fence_wait or fence_enable_sw_signaling
+ * haven't been called before.
+ *
+ * It's recommended for seqno fences to call fence_signal when the
+ * operation is complete, it makes it possible to prevent issues from
+ * wraparound between time of issue and time of use by checking the return
+ * value of this function before calling hardware-specific wait instructions.
+ */
+static inline bool
+fence_is_signaled(struct fence *fence)
+{
+	if (test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+		return true;
+
+	if (fence->ops->signaled && fence->ops->signaled(fence)) {
+		fence_signal(fence);
+		return true;
+	}
+
+	return false;
+}
+
+/**
+ * fence_later - return the chronologically later fence
+ * @f1:	[in]	the first fence from the same context
+ * @f2:	[in]	the second fence from the same context
+ *
+ * Returns NULL if both fences are signaled, otherwise the fence that would be
+ * signaled last. Both fences must be from the same context, since a seqno is
+ * not re-used across contexts.
+ */
+static inline struct fence *fence_later(struct fence *f1, struct fence *f2)
+{
+	if (WARN_ON(f1->context != f2->context))
+		return NULL;
+
+	/*
+	 * can't check just FENCE_FLAG_SIGNALED_BIT here, it may never have been
+	 * set if enable_signaling wasn't called, and enabling that here is
+	 * overkill.
+	 */
+	if (f2->seqno - f1->seqno <= INT_MAX)
+		return fence_is_signaled(f2) ? NULL : f2;
+	else
+		return fence_is_signaled(f1) ? NULL : f1;
+}
+
+signed long fence_wait_timeout(struct fence *, bool intr, signed long timeout);
+
+
+/**
+ * fence_wait - sleep until the fence gets signaled
+ * @fence:	[in]	the fence to wait on
+ * @intr:	[in]	if true, do an interruptible wait
+ *
+ * This function will return -ERESTARTSYS if interrupted by a signal,
+ * or 0 if the fence was signaled. Other error values may be
+ * returned on custom implementations.
+ *
+ * Performs a synchronous wait on this fence. It is assumed the caller
+ * directly or indirectly holds a reference to the fence, otherwise the
+ * fence might be freed before return, resulting in undefined behavior.
+ */
+static inline signed long fence_wait(struct fence *fence, bool intr)
+{
+	signed long ret;
+
+	/* Since fence_wait_timeout cannot timeout with
+	 * MAX_SCHEDULE_TIMEOUT, only valid return values are
+	 * -ERESTARTSYS and MAX_SCHEDULE_TIMEOUT.
+	 */
+	ret = fence_wait_timeout(fence, intr, MAX_SCHEDULE_TIMEOUT);
+
+	return ret < 0 ? ret : 0;
+}
+
+unsigned fence_context_alloc(unsigned num);
+
+#define FENCE_TRACE(f, fmt, args...) \
+	do {								\
+		struct fence *__ff = (f);				\
+		if (config_enabled(CONFIG_FENCE_TRACE))			\
+			pr_info("f %u#%u: " fmt,			\
+				__ff->context, __ff->seqno, ##args);	\
+	} while (0)
+
+#define FENCE_WARN(f, fmt, args...) \
+	do {								\
+		struct fence *__ff = (f);				\
+		pr_warn("f %u#%u: " fmt, __ff->context, __ff->seqno,	\
+			 ##args);					\
+	} while (0)
+
+#define FENCE_ERR(f, fmt, args...) \
+	do {								\
+		struct fence *__ff = (f);				\
+		pr_err("f %u#%u: " fmt, __ff->context, __ff->seqno,	\
+			##args);					\
+	} while (0)
+
+#endif /* __LINUX_FENCE_H */
diff --git a/include/linux/firmware.h b/include/linux/firmware.h
index 59529330efd6..5c41c5e75b5c 100644
--- a/include/linux/firmware.h
+++ b/include/linux/firmware.h
@@ -45,6 +45,8 @@ int request_firmware_nowait(
 	struct module *module, bool uevent,
 	const char *name, struct device *device, gfp_t gfp, void *context,
 	void (*cont)(const struct firmware *fw, void *context));
+int request_firmware_direct(const struct firmware **fw, const char *name,
+			    struct device *device);
 
 void release_firmware(const struct firmware *fw);
 #else
@@ -66,13 +68,12 @@ static inline void release_firmware(const struct firmware *fw)
 {
 }
 
-#endif
+static inline int request_firmware_direct(const struct firmware **fw,
+					  const char *name,
+					  struct device *device)
+{
+	return -EINVAL;
+}
 
-#ifdef CONFIG_FW_LOADER_USER_HELPER
-int request_firmware_direct(const struct firmware **fw, const char *name,
-			    struct device *device);
-#else
-#define request_firmware_direct	request_firmware
 #endif
-
 #endif
diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index 16f6654082dd..153d303af7eb 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -28,6 +28,7 @@ struct platform_device {
 	struct resource	*resource;
 
 	const struct platform_device_id	*id_entry;
+	char *driver_override; /* Driver name to force a match */
 
 	/* MFD cell pointer */
 	struct mfd_cell *mfd_cell;
diff --git a/include/linux/reservation.h b/include/linux/reservation.h
index 813dae960ebd..5a0b64cf68b4 100644
--- a/include/linux/reservation.h
+++ b/include/linux/reservation.h
@@ -6,7 +6,7 @@
  * Copyright (C) 2012 Texas Instruments
  *
  * Authors:
- * Rob Clark <rob.clark@linaro.org>
+ * Rob Clark <robdclark@gmail.com>
  * Maarten Lankhorst <maarten.lankhorst@canonical.com>
  * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
  *
@@ -40,23 +40,103 @@
 #define _LINUX_RESERVATION_H
 
 #include <linux/ww_mutex.h>
+#include <linux/fence.h>
+#include <linux/slab.h>
+#include <linux/seqlock.h>
+#include <linux/rcupdate.h>
 
 extern struct ww_class reservation_ww_class;
+extern struct lock_class_key reservation_seqcount_class;
+extern const char reservation_seqcount_string[];
+
+struct reservation_object_list {
+	struct rcu_head rcu;
+	u32 shared_count, shared_max;
+	struct fence __rcu *shared[];
+};
 
 struct reservation_object {
 	struct ww_mutex lock;
+	seqcount_t seq;
+
+	struct fence __rcu *fence_excl;
+	struct reservation_object_list __rcu *fence;
+	struct reservation_object_list *staged;
 };
 
+#define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base)
+#define reservation_object_assert_held(obj) \
+	lockdep_assert_held(&(obj)->lock.base)
+
 static inline void
 reservation_object_init(struct reservation_object *obj)
 {
 	ww_mutex_init(&obj->lock, &reservation_ww_class);
+
+	__seqcount_init(&obj->seq, reservation_seqcount_string, &reservation_seqcount_class);
+	RCU_INIT_POINTER(obj->fence, NULL);
+	RCU_INIT_POINTER(obj->fence_excl, NULL);
+	obj->staged = NULL;
 }
 
 static inline void
 reservation_object_fini(struct reservation_object *obj)
 {
+	int i;
+	struct reservation_object_list *fobj;
+	struct fence *excl;
+
+	/*
+	 * This object should be dead and all references must have
+	 * been released to it, so no need to be protected with rcu.
+	 */
+	excl = rcu_dereference_protected(obj->fence_excl, 1);
+	if (excl)
+		fence_put(excl);
+
+	fobj = rcu_dereference_protected(obj->fence, 1);
+	if (fobj) {
+		for (i = 0; i < fobj->shared_count; ++i)
+			fence_put(rcu_dereference_protected(fobj->shared[i], 1));
+
+		kfree(fobj);
+	}
+	kfree(obj->staged);
+
 	ww_mutex_destroy(&obj->lock);
 }
 
+static inline struct reservation_object_list *
+reservation_object_get_list(struct reservation_object *obj)
+{
+	return rcu_dereference_protected(obj->fence,
+					 reservation_object_held(obj));
+}
+
+static inline struct fence *
+reservation_object_get_excl(struct reservation_object *obj)
+{
+	return rcu_dereference_protected(obj->fence_excl,
+					 reservation_object_held(obj));
+}
+
+int reservation_object_reserve_shared(struct reservation_object *obj);
+void reservation_object_add_shared_fence(struct reservation_object *obj,
+					 struct fence *fence);
+
+void reservation_object_add_excl_fence(struct reservation_object *obj,
+				       struct fence *fence);
+
+int reservation_object_get_fences_rcu(struct reservation_object *obj,
+				      struct fence **pfence_excl,
+				      unsigned *pshared_count,
+				      struct fence ***pshared);
+
+long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
+					 bool wait_all, bool intr,
+					 unsigned long timeout);
+
+bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
+					  bool test_all);
+
 #endif /* _LINUX_RESERVATION_H */
diff --git a/include/linux/seqno-fence.h b/include/linux/seqno-fence.h
new file mode 100644
index 000000000000..3d6003de4b0d
--- /dev/null
+++ b/include/linux/seqno-fence.h
@@ -0,0 +1,116 @@
+/*
+ * seqno-fence, using a dma-buf to synchronize fencing
+ *
+ * Copyright (C) 2012 Texas Instruments
+ * Copyright (C) 2012 Canonical Ltd
+ * Authors:
+ *   Rob Clark <robdclark@gmail.com>
+ *   Maarten Lankhorst <maarten.lankhorst@canonical.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_SEQNO_FENCE_H
+#define __LINUX_SEQNO_FENCE_H
+
+#include <linux/fence.h>
+#include <linux/dma-buf.h>
+
+enum seqno_fence_condition {
+	SEQNO_FENCE_WAIT_GEQUAL,
+	SEQNO_FENCE_WAIT_NONZERO
+};
+
+struct seqno_fence {
+	struct fence base;
+
+	const struct fence_ops *ops;
+	struct dma_buf *sync_buf;
+	uint32_t seqno_ofs;
+	enum seqno_fence_condition condition;
+};
+
+extern const struct fence_ops seqno_fence_ops;
+
+/**
+ * to_seqno_fence - cast a fence to a seqno_fence
+ * @fence: fence to cast to a seqno_fence
+ *
+ * Returns NULL if the fence is not a seqno_fence,
+ * or the seqno_fence otherwise.
+ */
+static inline struct seqno_fence *
+to_seqno_fence(struct fence *fence)
+{
+	if (fence->ops != &seqno_fence_ops)
+		return NULL;
+	return container_of(fence, struct seqno_fence, base);
+}
+
+/**
+ * seqno_fence_init - initialize a seqno fence
+ * @fence: seqno_fence to initialize
+ * @lock: pointer to spinlock to use for fence
+ * @sync_buf: buffer containing the memory location to signal on
+ * @context: the execution context this fence is a part of
+ * @seqno_ofs: the offset within @sync_buf
+ * @seqno: the sequence # to signal on
+ * @ops: the fence_ops for operations on this seqno fence
+ *
+ * This function initializes a struct seqno_fence with passed parameters,
+ * and takes a reference on sync_buf which is released on fence destruction.
+ *
+ * A seqno_fence is a dma_fence which can complete in software when
+ * enable_signaling is called, but it also completes when
+ * (s32)((sync_buf)[seqno_ofs] - seqno) >= 0 is true
+ *
+ * The seqno_fence will take a refcount on the sync_buf until it's
+ * destroyed, but actual lifetime of sync_buf may be longer if one of the
+ * callers take a reference to it.
+ *
+ * Certain hardware have instructions to insert this type of wait condition
+ * in the command stream, so no intervention from software would be needed.
+ * This type of fence can be destroyed before completed, however a reference
+ * on the sync_buf dma-buf can be taken. It is encouraged to re-use the same
+ * dma-buf for sync_buf, since mapping or unmapping the sync_buf to the
+ * device's vm can be expensive.
+ *
+ * It is recommended for creators of seqno_fence to call fence_signal
+ * before destruction. This will prevent possible issues from wraparound at
+ * time of issue vs time of check, since users can check fence_is_signaled
+ * before submitting instructions for the hardware to wait on the fence.
+ * However, when ops.enable_signaling is not called, it doesn't have to be
+ * done as soon as possible, just before there's any real danger of seqno
+ * wraparound.
+ */
+static inline void
+seqno_fence_init(struct seqno_fence *fence, spinlock_t *lock,
+		 struct dma_buf *sync_buf,  uint32_t context,
+		 uint32_t seqno_ofs, uint32_t seqno,
+		 enum seqno_fence_condition cond,
+		 const struct fence_ops *ops)
+{
+	BUG_ON(!fence || !sync_buf || !ops);
+	BUG_ON(!ops->wait || !ops->enable_signaling ||
+	       !ops->get_driver_name || !ops->get_timeline_name);
+
+	/*
+	 * ops is used in fence_init for get_driver_name, so needs to be
+	 * initialized first
+	 */
+	fence->ops = ops;
+	fence_init(&fence->base, &seqno_fence_ops, lock, context, seqno);
+	get_dma_buf(sync_buf);
+	fence->sync_buf = sync_buf;
+	fence->seqno_ofs = seqno_ofs;
+	fence->condition = cond;
+}
+
+#endif /* __LINUX_SEQNO_FENCE_H */