[PATCH v4 05/14] dma-buf/sync_file: Add SET_DEADLINE ioctl

[Rob Clark <robdclark@gmail.com>]

From: Rob Clark <robdclark@chromium.org>

The initial purpose is for igt tests, but this would also be useful for
compositors that wait until close to vblank deadline to make decisions
about which frame to show.

The igt tests can be found at:

https://gitlab.freedesktop.org/robclark/igt-gpu-tools/-/commits/fence-deadline

v2: Clarify the timebase, add link to igt tests

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/dma-buf/sync_file.c    | 19 +++++++++++++++++++
 include/uapi/linux/sync_file.h | 22 ++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index af57799c86ce..fb6ca1032885 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -350,6 +350,22 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
 	return ret;
 }
 
+static int sync_file_ioctl_set_deadline(struct sync_file *sync_file,
+					unsigned long arg)
+{
+	struct sync_set_deadline ts;
+
+	if (copy_from_user(&ts, (void __user *)arg, sizeof(ts)))
+		return -EFAULT;
+
+	if (ts.pad)
+		return -EINVAL;
+
+	dma_fence_set_deadline(sync_file->fence, ktime_set(ts.tv_sec, ts.tv_nsec));
+
+	return 0;
+}
+
 static long sync_file_ioctl(struct file *file, unsigned int cmd,
 			    unsigned long arg)
 {
@@ -362,6 +378,9 @@ static long sync_file_ioctl(struct file *file, unsigned int cmd,
 	case SYNC_IOC_FILE_INFO:
 		return sync_file_ioctl_fence_info(sync_file, arg);
 
+	case SYNC_IOC_SET_DEADLINE:
+		return sync_file_ioctl_set_deadline(sync_file, arg);
+
 	default:
 		return -ENOTTY;
 	}
diff --git a/include/uapi/linux/sync_file.h b/include/uapi/linux/sync_file.h
index ee2dcfb3d660..c8666580816f 100644
--- a/include/uapi/linux/sync_file.h
+++ b/include/uapi/linux/sync_file.h
@@ -67,6 +67,20 @@ struct sync_file_info {
 	__u64	sync_fence_info;
 };
 
+/**
+ * struct sync_set_deadline - set a deadline on a fence
+ * @tv_sec:	seconds elapsed since epoch
+ * @tv_nsec:	nanoseconds elapsed since the time given by the tv_sec
+ * @pad:	must be zero
+ *
+ * The timebase for the deadline is CLOCK_MONOTONIC (same as vblank)
+ */
+struct sync_set_deadline {
+	__s64	tv_sec;
+	__s32	tv_nsec;
+	__u32	pad;
+};
+
 #define SYNC_IOC_MAGIC		'>'
 
 /**
@@ -95,4 +109,12 @@ struct sync_file_info {
  */
 #define SYNC_IOC_FILE_INFO	_IOWR(SYNC_IOC_MAGIC, 4, struct sync_file_info)
 
+
+/**
+ * DOC: SYNC_IOC_SET_DEADLINE - set a deadline on a fence
+ *
+ * Allows userspace to set a deadline on a fence, see dma_fence_set_deadline()
+ */
+#define SYNC_IOC_SET_DEADLINE	_IOW(SYNC_IOC_MAGIC, 5, struct sync_set_deadline)
+
 #endif /* _UAPI_LINUX_SYNC_H */
-- 
2.39.1