diff options
| -rw-r--r-- | drivers/staging/android/sw_sync.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/drivers/staging/android/sw_sync.c b/drivers/staging/android/sw_sync.c index 039e1f48855f..62e8e6dc7953 100644 --- a/drivers/staging/android/sw_sync.c +++ b/drivers/staging/android/sw_sync.c @@ -25,6 +25,36 @@ #define CREATE_TRACE_POINTS #include "sync_trace.h" +/* + * SW SYNC validation framework + * + * A sync object driver that uses a 32bit counter to coordinate + * synchronization. Useful when there is no hardware primitive backing + * the synchronization. + * + * To start the framework just open: + * + * <debugfs>/sync/sw_sync + * + * That will create a sync timeline, all fences created under this timeline + * file descriptor will belong to the this timeline. + * + * The 'sw_sync' file can be opened many times as to create different + * timelines. + * + * Fences can be created with SW_SYNC_IOC_CREATE_FENCE ioctl with struct + * sw_sync_ioctl_create_fence as parameter. + * + * To increment the timeline counter, SW_SYNC_IOC_INC ioctl should be used + * with the increment as u32. This will update the last signaled value + * from the timeline and signal any fence that has a seqno smaller or equal + * to it. + * + * struct sw_sync_ioctl_create_fence + * @value: the seqno to initialise the fence with + * @name: the name of the new sync point + * @fence: return the fd of the new sync_file with the created fence + */ struct sw_sync_create_fence_data { __u32 value; char name[32]; @@ -35,6 +65,7 @@ struct sw_sync_create_fence_data { #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) static const struct fence_ops timeline_fence_ops; |