[PATCH v7 07/15] dma-buf/sw_sync: Add fence deadline support

[Rob Clark]

From: Rob Clark <robdclark at chromium.org>

This consists of simply storing the most recent deadline, and adding an
ioctl to retrieve the deadline.  This can be used in conjunction with
the SET_DEADLINE ioctl on a fence fd for testing.  Ie. create various
sw_sync fences, merge them into a fence-array, set deadline on the
fence-array and confirm that it is propagated properly to each fence.

v2: Switch UABI to express deadline as u64
v3: More verbose UAPI docs, show how to convert from timespec

Signed-off-by: Rob Clark <robdclark at chromium.org>
Reviewed-by: Christian König <christian.koenig at amd.com>
---
 drivers/dma-buf/sw_sync.c      | 58 ++++++++++++++++++++++++++++++++++
 drivers/dma-buf/sync_debug.h   |  2 ++
 include/uapi/linux/sync_file.h |  6 +++-
 3 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c
index 348b3a9170fa..3e2315ee955b 100644
--- a/drivers/dma-buf/sw_sync.c
+++ b/drivers/dma-buf/sw_sync.c
@@ -52,12 +52,28 @@ struct sw_sync_create_fence_data {
 	__s32	fence; /* fd of new fence */
 };
 
+/**
+ * struct sw_sync_get_deadline - get the deadline hint of a sw_sync fence
+ * @deadline_ns: absolute time of the deadline
+ * @pad:	must be zero
+ * @fence_fd:	the sw_sync fence fd (in)
+ *
+ * The timebase for the deadline is CLOCK_MONOTONIC (same as vblank)
+ */
+struct sw_sync_get_deadline {
+	__u64	deadline_ns;
+	__u32	pad;
+	__s32	fence_fd;
+};
+
 #define SW_SYNC_IOC_MAGIC	'W'
 
 #define SW_SYNC_IOC_CREATE_FENCE	_IOWR(SW_SYNC_IOC_MAGIC, 0,\
 		struct sw_sync_create_fence_data)
 
 #define SW_SYNC_IOC_INC			_IOW(SW_SYNC_IOC_MAGIC, 1, __u32)
+#define SW_SYNC_GET_DEADLINE		_IOWR(SW_SYNC_IOC_MAGIC, 2, \
+		struct sw_sync_get_deadline)
 
 static const struct dma_fence_ops timeline_fence_ops;
 
@@ -171,6 +187,13 @@ static void timeline_fence_timeline_value_str(struct dma_fence *fence,
 	snprintf(str, size, "%d", parent->value);
 }
 
+static void timeline_fence_set_deadline(struct dma_fence *fence, ktime_t deadline)
+{
+	struct sync_pt *pt = dma_fence_to_sync_pt(fence);
+
+	pt->deadline = deadline;
+}
+
 static const struct dma_fence_ops timeline_fence_ops = {
 	.get_driver_name = timeline_fence_get_driver_name,
 	.get_timeline_name = timeline_fence_get_timeline_name,
@@ -179,6 +202,7 @@ static const struct dma_fence_ops timeline_fence_ops = {
 	.release = timeline_fence_release,
 	.fence_value_str = timeline_fence_value_str,
 	.timeline_value_str = timeline_fence_timeline_value_str,
+	.set_deadline = timeline_fence_set_deadline,
 };
 
 /**
@@ -387,6 +411,37 @@ static long sw_sync_ioctl_inc(struct sync_timeline *obj, unsigned long arg)
 	return 0;
 }
 
+static int sw_sync_ioctl_get_deadline(struct sync_timeline *obj, unsigned long arg)
+{
+	struct sw_sync_get_deadline data;
+	struct dma_fence *fence;
+	struct sync_pt *pt;
+
+	if (copy_from_user(&data, (void __user *)arg, sizeof(data)))
+		return -EFAULT;
+
+	if (data.deadline_ns || data.pad)
+		return -EINVAL;
+
+	fence = sync_file_get_fence(data.fence_fd);
+	if (!fence)
+		return -EINVAL;
+
+	pt = dma_fence_to_sync_pt(fence);
+	if (!pt)
+		return -EINVAL;
+
+
+	data.deadline_ns = ktime_to_ns(pt->deadline);
+
+	dma_fence_put(fence);
+
+	if (copy_to_user((void __user *)arg, &data, sizeof(data)))
+		return -EFAULT;
+
+	return 0;
+}
+
 static long sw_sync_ioctl(struct file *file, unsigned int cmd,
 			  unsigned long arg)
 {
@@ -399,6 +454,9 @@ static long sw_sync_ioctl(struct file *file, unsigned int cmd,
 	case SW_SYNC_IOC_INC:
 		return sw_sync_ioctl_inc(obj, arg);
 
+	case SW_SYNC_GET_DEADLINE:
+		return sw_sync_ioctl_get_deadline(obj, arg);
+
 	default:
 		return -ENOTTY;
 	}
diff --git a/drivers/dma-buf/sync_debug.h b/drivers/dma-buf/sync_debug.h
index 6176e52ba2d7..2e0146d0bdbb 100644
--- a/drivers/dma-buf/sync_debug.h
+++ b/drivers/dma-buf/sync_debug.h
@@ -55,11 +55,13 @@ static inline struct sync_timeline *dma_fence_parent(struct dma_fence *fence)
  * @base: base fence object
  * @link: link on the sync timeline's list
  * @node: node in the sync timeline's tree
+ * @deadline: the most recently set fence deadline
  */
 struct sync_pt {
 	struct dma_fence base;
 	struct list_head link;
 	struct rb_node node;
+	ktime_t deadline;
 };
 
 extern const struct file_operations sw_sync_debugfs_fops;
diff --git a/include/uapi/linux/sync_file.h b/include/uapi/linux/sync_file.h
index 49325cf6749b..dc6645b2598b 100644
--- a/include/uapi/linux/sync_file.h
+++ b/include/uapi/linux/sync_file.h
@@ -72,7 +72,11 @@ struct sync_file_info {
  * @deadline_ns: absolute time of the deadline
  * @pad:	must be zero
  *
- * The timebase for the deadline is CLOCK_MONOTONIC (same as vblank)
+ * The timebase for the deadline is CLOCK_MONOTONIC (same as vblank).  For
+ * example:
+ *
+ *     clock_gettime(CLOCK_MONOTONIC, &t);
+ *     deadline_ns = (t.tv_sec * 1000000000L) + t.tv_nsec + duration_ns
  */
 struct sync_set_deadline {
 	__u64	deadline_ns;
-- 
2.39.1