drm/radeon: improve semaphore debugging on lockup

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Author: Jerome Glisse

drivers/gpu/drm/radeon/radeon.h

@@ -654,6 +654,8 @@ struct radeon_ring {
 	u32			ptr_reg_mask;
 	u32			nop;
 	u32			idx;
+	u64			last_semaphore_signal_addr;
+	u64			last_semaphore_wait_addr;
 };
 
 /*

drivers/gpu/drm/radeon/radeon_ring.c

@@ -784,6 +784,8 @@ static int radeon_debugfs_ring_info(struct seq_file *m, void *data)
 	}
 	seq_printf(m, "driver's copy of the wptr: 0x%08x [%5d]\n", ring->wptr, ring->wptr);
 	seq_printf(m, "driver's copy of the rptr: 0x%08x [%5d]\n", ring->rptr, ring->rptr);
+	seq_printf(m, "last semaphore signal addr : 0x%016llx\n", ring->last_semaphore_signal_addr);
+	seq_printf(m, "last semaphore wait addr   : 0x%016llx\n", ring->last_semaphore_wait_addr);
 	seq_printf(m, "%u free dwords in ring\n", ring->ring_free_dw);
 	seq_printf(m, "%u dwords in ring\n", count);
 	/* print 8 dw before current rptr as often it's the last executed

drivers/gpu/drm/radeon/radeon_semaphore.c

@@ -95,6 +95,10 @@ int radeon_semaphore_sync_rings(struct radeon_device *rdev,
 	/* we assume caller has already allocated space on waiters ring */
 	radeon_semaphore_emit_wait(rdev, waiter, semaphore);
 
+	/* for debugging lockup only, used by sysfs debug files */
+	rdev->ring[signaler].last_semaphore_signal_addr = semaphore->gpu_addr;
+	rdev->ring[waiter].last_semaphore_wait_addr = semaphore->gpu_addr;
+
 	return 0;
 }