drm: rcar-du: Perform the initial CRTC setup from rcar_du_crtc_get()

The rcar_du_crtc_get() function is always immediately followed by a call
to rcar_du_crtc_setup(). Call the later from the former to simplify the
code, and add a comment to explain how the get and put calls are
balanced.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
index 6288b9a..c89751c 100644 (file)
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
@@ -66,39 +66,6 @@ static void rcar_du_crtc_clr_set(struct rcar_du_crtc *rcrtc, u32 reg,
        rcar_du_write(rcdu, rcrtc->mmio_offset + reg, (value & ~clr) | set);
 }
 
-static int rcar_du_crtc_get(struct rcar_du_crtc *rcrtc)
-{
-       int ret;
-
-       ret = clk_prepare_enable(rcrtc->clock);
-       if (ret < 0)
-               return ret;
-
-       ret = clk_prepare_enable(rcrtc->extclock);
-       if (ret < 0)
-               goto error_clock;
-
-       ret = rcar_du_group_get(rcrtc->group);
-       if (ret < 0)
-               goto error_group;
-
-       return 0;
-
-error_group:
-       clk_disable_unprepare(rcrtc->extclock);
-error_clock:
-       clk_disable_unprepare(rcrtc->clock);
-       return ret;
-}
-
-static void rcar_du_crtc_put(struct rcar_du_crtc *rcrtc)
-{
-       rcar_du_group_put(rcrtc->group);
-
-       clk_disable_unprepare(rcrtc->extclock);
-       clk_disable_unprepare(rcrtc->clock);
-}
-
 /* -----------------------------------------------------------------------------
  * Hardware Setup
  */
@@ -546,6 +513,51 @@ static void rcar_du_crtc_setup(struct rcar_du_crtc *rcrtc)
        drm_crtc_vblank_on(&rcrtc->crtc);
 }
 
+static int rcar_du_crtc_get(struct rcar_du_crtc *rcrtc)
+{
+       int ret;
+
+       /*
+        * Guard against double-get, as the function is called from both the
+        * .atomic_enable() and .atomic_begin() handlers.
+        */
+       if (rcrtc->initialized)
+               return 0;
+
+       ret = clk_prepare_enable(rcrtc->clock);
+       if (ret < 0)
+               return ret;
+
+       ret = clk_prepare_enable(rcrtc->extclock);
+       if (ret < 0)
+               goto error_clock;
+
+       ret = rcar_du_group_get(rcrtc->group);
+       if (ret < 0)
+               goto error_group;
+
+       rcar_du_crtc_setup(rcrtc);
+       rcrtc->initialized = true;
+
+       return 0;
+
+error_group:
+       clk_disable_unprepare(rcrtc->extclock);
+error_clock:
+       clk_disable_unprepare(rcrtc->clock);
+       return ret;
+}
+
+static void rcar_du_crtc_put(struct rcar_du_crtc *rcrtc)
+{
+       rcar_du_group_put(rcrtc->group);
+
+       clk_disable_unprepare(rcrtc->extclock);
+       clk_disable_unprepare(rcrtc->clock);
+
+       rcrtc->initialized = false;
+}
+
 static void rcar_du_crtc_start(struct rcar_du_crtc *rcrtc)
 {
        bool interlaced;
@@ -639,16 +651,7 @@ static void rcar_du_crtc_atomic_enable(struct drm_crtc *crtc,
 {
        struct rcar_du_crtc *rcrtc = to_rcar_crtc(crtc);
 
-       /*
-        * If the CRTC has already been setup by the .atomic_begin() handler we
-        * can skip the setup stage.
-        */
-       if (!rcrtc->initialized) {
-               rcar_du_crtc_get(rcrtc);
-               rcar_du_crtc_setup(rcrtc);
-               rcrtc->initialized = true;
-       }
-
+       rcar_du_crtc_get(rcrtc);
        rcar_du_crtc_start(rcrtc);
 }
 
@@ -667,7 +670,6 @@ static void rcar_du_crtc_atomic_disable(struct drm_crtc *crtc,
        }
        spin_unlock_irq(&crtc->dev->event_lock);
 
-       rcrtc->initialized = false;
        rcrtc->outputs = 0;
 }
 
@@ -680,14 +682,17 @@ static void rcar_du_crtc_atomic_begin(struct drm_crtc *crtc,
 
        /*
         * If a mode set is in progress we can be called with the CRTC disabled.
-        * We then need to first setup the CRTC in order to configure planes.
-        * The .atomic_enable() handler will notice and skip the CRTC setup.
+        * We thus need to first get and setup the CRTC in order to configure
+        * planes. We must *not* put the CRTC in .atomic_flush(), as it must be
+        * kept awake until the .atomic_enable() call that will follow. The get
+        * operation in .atomic_enable() will in that case be a no-op, and the
+        * CRTC will be put later in .atomic_disable().
+        *
+        * If a mode set is not in progress the CRTC is enabled, and the
+        * following get call will be a no-op. There is thus no need to belance
+        * it in .atomic_flush() either.
         */
-       if (!rcrtc->initialized) {
-               rcar_du_crtc_get(rcrtc);
-               rcar_du_crtc_setup(rcrtc);
-               rcrtc->initialized = true;
-       }
+       rcar_du_crtc_get(rcrtc);
 
        if (rcar_du_has(rcrtc->group->dev, RCAR_DU_FEATURE_VSP1_SOURCE))
                rcar_du_vsp_atomic_begin(rcrtc);