drm: rcar-du: crtc: Control CMM operations

Implement CMM handling in the crtc begin and enable atomic callbacks,
and enable CMM unit through the Display Extensional Functions
register at group setup time.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
[Fix printk format modifier for size_t variable]
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

drivers/gpu/drm/rcar-du/rcar_du_crtc.c

@@ -21,6 +21,7 @@
 #include <drm/drm_plane_helper.h>
 #include <drm/drm_vblank.h>
 
+#include "rcar_cmm.h"
 #include "rcar_du_crtc.h"
 #include "rcar_du_drv.h"
 #include "rcar_du_encoder.h"
@@ -474,6 +475,45 @@ static void rcar_du_crtc_wait_page_flip(struct rcar_du_crtc *rcrtc)
 	rcar_du_crtc_finish_page_flip(rcrtc);
 }
 
+/* -----------------------------------------------------------------------------
+ * Color Management Module (CMM)
+ */
+
+static int rcar_du_cmm_check(struct drm_crtc *crtc,
+			     struct drm_crtc_state *state)
+{
+	struct drm_property_blob *drm_lut = state->gamma_lut;
+	struct rcar_du_crtc *rcrtc = to_rcar_crtc(crtc);
+	struct device *dev = rcrtc->dev->dev;
+
+	if (!drm_lut)
+		return 0;
+
+	/* We only accept fully populated LUT tables. */
+	if (drm_color_lut_size(drm_lut) != CM2_LUT_SIZE) {
+		dev_err(dev, "invalid gamma lut size: %zu bytes\n",
+			drm_lut->length);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void rcar_du_cmm_setup(struct drm_crtc *crtc)
+{
+	struct drm_property_blob *drm_lut = crtc->state->gamma_lut;
+	struct rcar_du_crtc *rcrtc = to_rcar_crtc(crtc);
+	struct rcar_cmm_config cmm_config = {};
+
+	if (!rcrtc->cmm)
+		return;
+
+	if (drm_lut)
+		cmm_config.lut.table = (struct drm_color_lut *)drm_lut->data;
+
+	rcar_cmm_setup(rcrtc->cmm, &cmm_config);
+}
+
 /* -----------------------------------------------------------------------------
  * Start/Stop and Suspend/Resume
  */
@@ -619,6 +659,9 @@ static void rcar_du_crtc_stop(struct rcar_du_crtc *rcrtc)
 	if (rcar_du_has(rcrtc->dev, RCAR_DU_FEATURE_VSP1_SOURCE))
 		rcar_du_vsp_disable(rcrtc);
 
+	if (rcrtc->cmm)
+		rcar_cmm_disable(rcrtc->cmm);
+
 	/*
 	 * Select switch sync mode. This stops display operation and configures
 	 * the HSYNC and VSYNC signals as inputs.
@@ -642,6 +685,11 @@ static int rcar_du_crtc_atomic_check(struct drm_crtc *crtc,
 {
 	struct rcar_du_crtc_state *rstate = to_rcar_crtc_state(state);
 	struct drm_encoder *encoder;
+	int ret;
+
+	ret = rcar_du_cmm_check(crtc, state);
+	if (ret)
+		return ret;
 
 	/* Store the routes from the CRTC output to the DU outputs. */
 	rstate->outputs = 0;
@@ -667,6 +715,8 @@ static void rcar_du_crtc_atomic_enable(struct drm_crtc *crtc,
 	struct rcar_du_crtc_state *rstate = to_rcar_crtc_state(crtc->state);
 	struct rcar_du_device *rcdu = rcrtc->dev;
 
+	if (rcrtc->cmm)
+		rcar_cmm_enable(rcrtc->cmm);
 	rcar_du_crtc_get(rcrtc);
 
 	/*
@@ -686,6 +736,13 @@ static void rcar_du_crtc_atomic_enable(struct drm_crtc *crtc,
 	}
 
 	rcar_du_crtc_start(rcrtc);
+
+	/*
+	 * TODO: The chip manual indicates that CMM tables should be written
+	 * after the DU channel has been activated. Investigate the impact
+	 * of this restriction on the first displayed frame.
+	 */
+	rcar_du_cmm_setup(crtc);
 }
 
 static void rcar_du_crtc_atomic_disable(struct drm_crtc *crtc,
@@ -739,6 +796,10 @@ static void rcar_du_crtc_atomic_begin(struct drm_crtc *crtc,
 	 */
 	rcar_du_crtc_get(rcrtc);
 
+	/* If the active state changed, we let .atomic_enable handle CMM. */
+	if (crtc->state->color_mgmt_changed && !crtc->state->active_changed)
+		rcar_du_cmm_setup(crtc);
+
 	if (rcar_du_has(rcrtc->dev, RCAR_DU_FEATURE_VSP1_SOURCE))
 		rcar_du_vsp_atomic_begin(rcrtc);
 }

drivers/gpu/drm/rcar-du/rcar_du_group.c

@@ -135,6 +135,7 @@ static void rcar_du_group_setup_didsr(struct rcar_du_group *rgrp)
 static void rcar_du_group_setup(struct rcar_du_group *rgrp)
 {
 	struct rcar_du_device *rcdu = rgrp->dev;
+	u32 defr7 = DEFR7_CODE;
 
 	/* Enable extended features */
 	rcar_du_group_write(rgrp, DEFR, DEFR_CODE | DEFR_DEFE);
@@ -147,6 +148,15 @@ static void rcar_du_group_setup(struct rcar_du_group *rgrp)
 
 	rcar_du_group_setup_pins(rgrp);
 
+	/*
+	 * TODO: Handle routing of the DU output to CMM dynamically, as we
+	 * should bypass CMM completely when no color management feature is
+	 * used.
+	 */
+	defr7 |= (rgrp->cmms_mask & BIT(1) ? DEFR7_CMME1 : 0) |
+		 (rgrp->cmms_mask & BIT(0) ? DEFR7_CMME0 : 0);
+	rcar_du_group_write(rgrp, DEFR7, defr7);
+
 	if (rcdu->info->gen >= 2) {
 		rcar_du_group_setup_defr8(rgrp);
 		rcar_du_group_setup_didsr(rgrp);

drivers/gpu/drm/rcar-du/rcar_du_regs.h

@@ -197,6 +197,11 @@
 #define DEFR6_MLOS1		(1 << 2)
 #define DEFR6_DEFAULT		(DEFR6_CODE | DEFR6_TCNE1)
 
+#define DEFR7			0x000ec
+#define DEFR7_CODE		(0x7779 << 16)
+#define DEFR7_CMME1		BIT(6)
+#define DEFR7_CMME0		BIT(4)
+
 /* -----------------------------------------------------------------------------
  * R8A7790-only Control Registers
  */