drm/vc4: Move LBM creation out of vc4_plane_mode_set()

We are about to use vc4_plane_mode_set() in the async check path, and
async updates require that LBM size stay the same since they reuse the
LBM from the previous state. So we definitely don't want to allocate a
new LBM region that we know for sure will be free right away.

Move the LBM allocation out of vc4_plane_mode_set() and call the new
function (vc4_plane_update_lbm()) from vc4_plane_atomic_check().

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20181130090254.594-2-boris.brezillon@bootlin.com

diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index bd6ef1f..9ed05fb 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -338,6 +338,7 @@ struct vc4_plane_state {
        u32 pos0_offset;
        u32 pos2_offset;
        u32 ptr0_offset;
+       u32 lbm_offset;
 
        /* Offset where the plane's dlist was last stored in the
         * hardware at vc4_crtc_atomic_flush() time.

diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c
index f6e3e8d..2db021f 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_plane.c
+++ b/drivers/gpu/drm/vc4/vc4_plane.c
@@ -452,6 +452,43 @@ static void vc4_write_scaling_parameters(struct drm_plane_state *state,
        }
 }
 
+static int vc4_plane_allocate_lbm(struct drm_plane_state *state)
+{
+       struct vc4_dev *vc4 = to_vc4_dev(state->plane->dev);
+       struct vc4_plane_state *vc4_state = to_vc4_plane_state(state);
+       unsigned long irqflags;
+       u32 lbm_size;
+
+       lbm_size = vc4_lbm_size(state);
+       if (!lbm_size)
+               return 0;
+
+       if (WARN_ON(!vc4_state->lbm_offset))
+               return -EINVAL;
+
+       /* Allocate the LBM memory that the HVS will use for temporary
+        * storage due to our scaling/format conversion.
+        */
+       if (!vc4_state->lbm.allocated) {
+               int ret;
+
+               spin_lock_irqsave(&vc4->hvs->mm_lock, irqflags);
+               ret = drm_mm_insert_node_generic(&vc4->hvs->lbm_mm,
+                                                &vc4_state->lbm,
+                                                lbm_size, 32, 0, 0);
+               spin_unlock_irqrestore(&vc4->hvs->mm_lock, irqflags);
+
+               if (ret)
+                       return ret;
+       } else {
+               WARN_ON_ONCE(lbm_size != vc4_state->lbm.size);
+       }
+
+       vc4_state->dlist[vc4_state->lbm_offset] = vc4_state->lbm.start;
+
+       return 0;
+}
+
 /* Writes out a full display list for an active plane to the plane's
  * private dlist state.
  */
@@ -469,31 +506,11 @@ static int vc4_plane_mode_set(struct drm_plane *plane,
        bool mix_plane_alpha;
        bool covers_screen;
        u32 scl0, scl1, pitch0;
-       u32 lbm_size, tiling;
-       unsigned long irqflags;
+       u32 tiling;
        u32 hvs_format = format->hvs;
        int ret, i;
 
        ret = vc4_plane_setup_clipping_and_scaling(state);
-       if (ret)
-               return ret;
-
-       /* Allocate the LBM memory that the HVS will use for temporary
-        * storage due to our scaling/format conversion.
-        */
-       lbm_size = vc4_lbm_size(state);
-       if (lbm_size) {
-               if (!vc4_state->lbm.allocated) {
-                       spin_lock_irqsave(&vc4->hvs->mm_lock, irqflags);
-                       ret = drm_mm_insert_node_generic(&vc4->hvs->lbm_mm,
-                                                        &vc4_state->lbm,
-                                                        lbm_size, 32, 0, 0);
-                       spin_unlock_irqrestore(&vc4->hvs->mm_lock, irqflags);
-               } else {
-                       WARN_ON_ONCE(lbm_size != vc4_state->lbm.size);
-               }
-       }
-
        if (ret)
                return ret;
 
@@ -717,15 +734,18 @@ static int vc4_plane_mode_set(struct drm_plane *plane,
                vc4_dlist_write(vc4_state, SCALER_CSC2_ITR_R_601_5);
        }
 
+       vc4_state->lbm_offset = 0;
+
        if (vc4_state->x_scaling[0] != VC4_SCALING_NONE ||
            vc4_state->x_scaling[1] != VC4_SCALING_NONE ||
            vc4_state->y_scaling[0] != VC4_SCALING_NONE ||
            vc4_state->y_scaling[1] != VC4_SCALING_NONE) {
-               /* LBM Base Address. */
+               /* Reserve a slot for the LBM Base Address. The real value will
+                * be set when calling vc4_plane_allocate_lbm().
+                */
                if (vc4_state->y_scaling[0] != VC4_SCALING_NONE ||
-                   vc4_state->y_scaling[1] != VC4_SCALING_NONE) {
-                       vc4_dlist_write(vc4_state, vc4_state->lbm.start);
-               }
+                   vc4_state->y_scaling[1] != VC4_SCALING_NONE)
+                       vc4_state->lbm_offset = vc4_state->dlist_count++;
 
                if (num_planes > 1) {
                        /* Emit Cb/Cr as channel 0 and Y as channel
@@ -785,13 +805,18 @@ static int vc4_plane_atomic_check(struct drm_plane *plane,
                                  struct drm_plane_state *state)
 {
        struct vc4_plane_state *vc4_state = to_vc4_plane_state(state);
+       int ret;
 
        vc4_state->dlist_count = 0;
 
-       if (plane_enabled(state))
-               return vc4_plane_mode_set(plane, state);
-       else
+       if (!plane_enabled(state))
                return 0;
+
+       ret = vc4_plane_mode_set(plane, state);
+       if (ret)
+               return ret;
+
+       return vc4_plane_allocate_lbm(state);
 }
 
 static void vc4_plane_atomic_update(struct drm_plane *plane,