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From:   Rob Clark <robdclark@gmail.com>
To:     dri-devel@lists.freedesktop.org
Cc:     freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org,
        Brian Starkey <brian.starkey@arm.com>,
        Liviu Dudau <liviu.dudau@arm.com>,
        Rob Clark <robdclark@gmail.com>,
        David Airlie <airlied@linux.ie>,
        Archit Taneja <architt@codeaurora.org>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>,
        =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= 
        <ville.syrjala@linux.intel.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Sean Paul <seanpaul@chromium.org>,
        Sushmita Susheelendra <ssusheel@codeaurora.org>,
        linux-kernel@vger.kernel.org
Subject: [RFC 4/4] drm/msm/mdp5: writeback support
Date:   Fri, 23 Feb 2018 08:17:54 -0500
Message-Id: <20180223131758.18362-5-robdclark@gmail.com>
In-Reply-To: <20180223131758.18362-1-robdclark@gmail.com>
References: <20180223131758.18362-1-robdclark@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

In a way, based on the original writeback patch from Jilai Wang, but a
lot has shifted around since then.

Signed-off-by: Rob Clark <robdclark@gmail.com>
---
 drivers/gpu/drm/msm/Makefile              |   1 +
 drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c |  23 +-
 drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c  |  38 +++-
 drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h  |   7 +-
 drivers/gpu/drm/msm/disp/mdp5/mdp5_wb.c   | 367 ++++++++++++++++++++++++++++++
 drivers/gpu/drm/msm/dsi/dsi_host.c        |   4 +-
 6 files changed, 431 insertions(+), 9 deletions(-)
 create mode 100644 drivers/gpu/drm/msm/disp/mdp5/mdp5_wb.c

diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
index cd40c050b2d7..c9f50adef2db 100644
--- a/drivers/gpu/drm/msm/Makefile
+++ b/drivers/gpu/drm/msm/Makefile
@@ -45,6 +45,7 @@ msm-y := \
 	disp/mdp5/mdp5_mixer.o \
 	disp/mdp5/mdp5_plane.o \
 	disp/mdp5/mdp5_smp.o \
+	disp/mdp5/mdp5_wb.o \
 	msm_atomic.o \
 	msm_debugfs.o \
 	msm_drv.o \
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c
index 9893e43ba6c5..b00ca88b741d 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c
@@ -484,7 +484,11 @@ static void mdp5_crtc_atomic_enable(struct drm_crtc *crtc,
 	}
 
 	/* Restore vblank irq handling after power is enabled */
-	drm_crtc_vblank_on(crtc);
+// TODO we can't ->get_scanout_pos() for wb (since virtual intf)..
+// perhaps drm core should be clever enough not to drm_reset_vblank_timestamp()
+// for virtual encoders / writeback?
+	if (mdp5_cstate->pipeline.intf->type != INTF_WB)
+		drm_crtc_vblank_on(crtc);
 
 	mdp5_crtc_mode_set_nofb(crtc);
 
@@ -518,7 +522,11 @@ int mdp5_crtc_setup_pipeline(struct drm_crtc *crtc,
 		u32 caps;
 		int ret;
 
-		caps = MDP_LM_CAP_DISPLAY;
+		if (pipeline->intf->type == INTF_WB)
+			caps = MDP_LM_CAP_WB;
+		else
+			caps = MDP_LM_CAP_DISPLAY;
+
 		if (need_right_mixer)
 			caps |= MDP_LM_CAP_PAIR;
 
@@ -545,6 +553,7 @@ int mdp5_crtc_setup_pipeline(struct drm_crtc *crtc,
 	mdp5_cstate->err_irqmask = intf2err(intf->num);
 	mdp5_cstate->vblank_irqmask = intf2vblank(pipeline->mixer, intf);
 
+// XXX should we be treating WB as cmd_mode??
 	if ((intf->type == INTF_DSI) &&
 	    (intf->mode == MDP5_INTF_DSI_MODE_COMMAND)) {
 		mdp5_cstate->pp_done_irqmask = lm2ppdone(pipeline->mixer);
@@ -639,8 +648,12 @@ static int mdp5_crtc_atomic_check(struct drm_crtc *crtc,
 	}
 
 	/* bail out early if there aren't any planes */
-	if (!cnt)
-		return 0;
+	if (!cnt) {
+		if (!state->active)
+			return 0;
+		dev_err(dev->dev, "%s has no planes!\n", crtc->name);
+		return -EINVAL;
+	}
 
 	hw_cfg = mdp5_cfg_get_hw_config(mdp5_kms->cfg);
 
@@ -1160,7 +1173,7 @@ void mdp5_crtc_wait_for_commit_done(struct drm_crtc *crtc)
 
 	if (mdp5_cstate->cmd_mode)
 		mdp5_crtc_wait_for_pp_done(crtc);
-	else
+	else if (mdp5_cstate->pipeline.intf->type != INTF_WB)
 		mdp5_crtc_wait_for_flush_done(crtc);
 }
 
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
index 1f44d8f15ce1..239010905637 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
@@ -427,7 +427,8 @@ static int modeset_init(struct mdp5_kms *mdp5_kms)
 	 * the MDP5 interfaces) than the number of layer mixers present in HW,
 	 * but let's be safe here anyway
 	 */
-	num_crtcs = min(priv->num_encoders, mdp5_kms->num_hwmixers);
+	num_crtcs = min(priv->num_encoders + hw_cfg->wb.count,
+			mdp5_kms->num_hwmixers);
 
 	/*
 	 * Construct planes equaling the number of hw pipes, and CRTCs for the
@@ -482,6 +483,33 @@ static int modeset_init(struct mdp5_kms *mdp5_kms)
 		encoder->possible_crtcs = (1 << priv->num_crtcs) - 1;
 	}
 
+	/*
+	 * Lastly, construct writeback connectors.
+	 */
+	for (i = 0; i < hw_cfg->wb.count; i++) {
+		struct drm_writeback_connector *wb_conn;
+		struct mdp5_ctl *ctl;
+
+		ctl = mdp5_ctlm_request(mdp5_kms->ctlm, -1);
+		if (!ctl) {
+			dev_err(dev->dev,
+				"failed to allocate ctl for writeback %d\n", i);
+			continue;
+		}
+
+		wb_conn = mdp5_wb_connector_init(dev, ctl,
+				hw_cfg->wb.instances[i].id);
+		if (IS_ERR(wb_conn)) {
+			ret = PTR_ERR(wb_conn);
+			dev_err(dev->dev,
+				"failed to construct writeback connector %d (%d)\n",
+				i, ret);
+			goto fail;
+		}
+
+		wb_conn->encoder.possible_crtcs = (1 << priv->num_crtcs) - 1;
+	}
+
 	return 0;
 
 fail:
@@ -555,6 +583,10 @@ static bool mdp5_get_scanoutpos(struct drm_device *dev, unsigned int pipe,
 		return false;
 	}
 
+	/* unsupported for writeback: */
+	if (encoder->encoder_type == DRM_MODE_ENCODER_VIRTUAL)
+		return false;
+
 	vsw = mode->crtc_vsync_end - mode->crtc_vsync_start;
 	vbp = mode->crtc_vtotal - mode->crtc_vsync_end;
 
@@ -610,6 +642,10 @@ static u32 mdp5_get_vblank_counter(struct drm_device *dev, unsigned int pipe)
 	if (!encoder)
 		return 0;
 
+	/* unsupported for writeback: */
+	if (encoder->encoder_type == DRM_MODE_ENCODER_VIRTUAL)
+		return 0;
+
 	return mdp5_encoder_get_framecount(encoder);
 }
 
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h
index 425a03d213e5..be0f93ef33e1 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h
@@ -18,6 +18,8 @@
 #ifndef __MDP5_KMS_H__
 #define __MDP5_KMS_H__
 
+#include <drm/drm_writeback.h>
+
 #include "msm_drv.h"
 #include "msm_kms.h"
 #include "disp/mdp_kms.h"
@@ -251,7 +253,7 @@ static inline uint32_t intf2vblank(struct mdp5_hw_mixer *mixer,
 		return MDP5_IRQ_PING_PONG_0_RD_PTR << mixer->pp;
 
 	if (intf->type == INTF_WB)
-		return MDP5_IRQ_WB_2_DONE;
+		return MDP5_IRQ_WB_2_DONE | MDP5_IRQ_WB_0_DONE | MDP5_IRQ_WB_1_DONE;
 
 	switch (intf->num) {
 	case 0:  return MDP5_IRQ_INTF0_VSYNC;
@@ -330,4 +332,7 @@ static inline int mdp5_cmd_encoder_set_split_display(
 }
 #endif
 
+struct drm_writeback_connector *mdp5_wb_connector_init(struct drm_device *dev,
+		struct mdp5_ctl *ctl, unsigned wb_id);
+
 #endif /* __MDP5_KMS_H__ */
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_wb.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_wb.c
new file mode 100644
index 000000000000..3dabd0a1aa8b
--- /dev/null
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_wb.c
@@ -0,0 +1,367 @@
+/*
+ * Copyright (C) 2018 Red Hat
+ * Author: Rob Clark <robdclark@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "mdp5_kms.h"
+
+/*
+ * Writeback connector/encoder implementation:
+ */
+
+struct mdp5_wb_connector {
+	struct drm_writeback_connector base;
+
+	u32 nformats;
+	u32 formats[32];
+
+	unsigned id;
+	struct mdp5_ctl *ctl;
+	struct mdp5_interface *intf;
+
+	struct mdp_irq wb_done;
+};
+#define to_mdp5_wb_connector(x) container_of(x, struct mdp5_wb_connector, base)
+
+
+static void mdp5_wb_connector_atomic_commit(struct drm_connector *connector,
+		struct drm_writeback_job *job);
+
+static int mdp5_wb_connector_get_modes(struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+
+	return drm_add_modes_noedid(connector, dev->mode_config.max_width,
+			dev->mode_config.max_height);
+}
+
+static enum drm_mode_status
+mdp5_wb_connector_mode_valid(struct drm_connector *connector,
+		struct drm_display_mode *mode)
+{
+	struct drm_device *dev = connector->dev;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	int w = mode->hdisplay, h = mode->vdisplay;
+
+	if ((w < mode_config->min_width) || (w > mode_config->max_width))
+		return MODE_BAD_HVALUE;
+
+	if ((h < mode_config->min_height) || (h > mode_config->max_height))
+		return MODE_BAD_VVALUE;
+
+	return MODE_OK;
+}
+
+const struct drm_connector_helper_funcs mdp5_wb_connector_helper_funcs = {
+	.get_modes = mdp5_wb_connector_get_modes,
+	.mode_valid = mdp5_wb_connector_mode_valid,
+	.atomic_commit = mdp5_wb_connector_atomic_commit,
+};
+
+static enum drm_connector_status
+mdp5_wb_connector_detect(struct drm_connector *connector, bool force)
+{
+	return connector_status_disconnected;
+}
+
+static void mdp5_wb_connector_destroy(struct drm_connector *connector)
+{
+	drm_connector_cleanup(connector);
+}
+
+static const struct drm_connector_funcs mdp5_wb_connector_funcs = {
+	.reset = drm_atomic_helper_connector_reset,
+	.detect = mdp5_wb_connector_detect,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.destroy = mdp5_wb_connector_destroy,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static int
+mdp5_wb_encoder_atomic_check(struct drm_encoder *encoder,
+		struct drm_crtc_state *crtc_state,
+		struct drm_connector_state *conn_state)
+{
+	struct msm_drm_private *priv = encoder->dev->dev_private;
+	struct mdp5_crtc_state *mdp5_cstate = to_mdp5_crtc_state(crtc_state);
+	struct mdp5_wb_connector *mdp5_wb = to_mdp5_wb_connector(
+		to_wb_connector(conn_state->connector));
+	struct drm_framebuffer *fb;
+	const struct msm_format *format;
+	const struct mdp_format *mdp_fmt;
+	struct drm_format_name_buf format_name;
+	int ret;
+
+	if (!conn_state->writeback_job || !conn_state->writeback_job->fb)
+		return 0;
+
+	fb = conn_state->writeback_job->fb;
+
+	DBG("wb[%u]: check writeback %ux%u@%s", mdp5_wb->id,
+		fb->width, fb->height,
+		drm_get_format_name(fb->format->format, &format_name));
+
+	format = mdp_get_format(priv->kms, fb->format->format);
+	if (!format) {
+		DBG("Invalid pixel format!");
+		return -EINVAL;
+	}
+
+	mdp_fmt = to_mdp_format(format);
+	if (MDP_FORMAT_IS_YUV(mdp_fmt)) {
+		switch (mdp_fmt->chroma_sample) {
+		case CHROMA_420:
+		case CHROMA_H2V1:
+			/* supported */
+			break;
+		case CHROMA_H1V2:
+		default:
+			DBG("unsupported wb chroma samp=%d\n",
+				mdp_fmt->chroma_sample);
+			return -EINVAL;
+		}
+	}
+
+	/* TODO I think we would prefer to have proper prepare_fb()/cleanup_fb()
+	 * vfuncs, as with plane..  Also, where to unprepare?
+	 */
+	ret = msm_framebuffer_prepare(fb, priv->kms->aspace);
+	if (ret)
+		return ret;
+
+	mdp5_cstate->ctl = mdp5_wb->ctl;
+	mdp5_cstate->pipeline.intf = mdp5_wb->intf;
+	mdp5_cstate->defer_start = true;
+
+	return 0;
+}
+
+static void
+wb_csc_setup(struct mdp5_kms *mdp5_kms, u32 wb_id, struct csc_cfg *csc)
+{
+	uint32_t  i;
+	uint32_t *matrix;
+
+	if (unlikely(!csc))
+		return;
+
+	matrix = csc->matrix;
+	mdp5_write(mdp5_kms, REG_MDP5_WB_CSC_MATRIX_COEFF_0(wb_id),
+		MDP5_WB_CSC_MATRIX_COEFF_0_COEFF_11(matrix[0]) |
+		MDP5_WB_CSC_MATRIX_COEFF_0_COEFF_12(matrix[1]));
+	mdp5_write(mdp5_kms, REG_MDP5_WB_CSC_MATRIX_COEFF_1(wb_id),
+		MDP5_WB_CSC_MATRIX_COEFF_1_COEFF_13(matrix[2]) |
+		MDP5_WB_CSC_MATRIX_COEFF_1_COEFF_21(matrix[3]));
+	mdp5_write(mdp5_kms, REG_MDP5_WB_CSC_MATRIX_COEFF_2(wb_id),
+		MDP5_WB_CSC_MATRIX_COEFF_2_COEFF_22(matrix[4]) |
+		MDP5_WB_CSC_MATRIX_COEFF_2_COEFF_23(matrix[5]));
+	mdp5_write(mdp5_kms, REG_MDP5_WB_CSC_MATRIX_COEFF_3(wb_id),
+		MDP5_WB_CSC_MATRIX_COEFF_3_COEFF_31(matrix[6]) |
+		MDP5_WB_CSC_MATRIX_COEFF_3_COEFF_32(matrix[7]));
+	mdp5_write(mdp5_kms, REG_MDP5_WB_CSC_MATRIX_COEFF_4(wb_id),
+		MDP5_WB_CSC_MATRIX_COEFF_4_COEFF_33(matrix[8]));
+
+	for (i = 0; i < ARRAY_SIZE(csc->pre_bias); i++) {
+		uint32_t *pre_clamp = csc->pre_clamp;
+		uint32_t *post_clamp = csc->post_clamp;
+
+		mdp5_write(mdp5_kms, REG_MDP5_WB_CSC_COMP_PRECLAMP(wb_id, i),
+			MDP5_WB_CSC_COMP_PRECLAMP_REG_HIGH(pre_clamp[2*i+1]) |
+			MDP5_WB_CSC_COMP_PRECLAMP_REG_LOW(pre_clamp[2*i]));
+
+		mdp5_write(mdp5_kms, REG_MDP5_WB_CSC_COMP_POSTCLAMP(wb_id, i),
+			MDP5_WB_CSC_COMP_POSTCLAMP_REG_HIGH(post_clamp[2*i+1]) |
+			MDP5_WB_CSC_COMP_POSTCLAMP_REG_LOW(post_clamp[2*i]));
+
+		mdp5_write(mdp5_kms, REG_MDP5_WB_CSC_COMP_PREBIAS(wb_id, i),
+			MDP5_WB_CSC_COMP_PREBIAS_REG_VALUE(csc->pre_bias[i]));
+
+		mdp5_write(mdp5_kms, REG_MDP5_WB_CSC_COMP_POSTBIAS(wb_id, i),
+			MDP5_WB_CSC_COMP_POSTBIAS_REG_VALUE(csc->post_bias[i]));
+	}
+}
+
+static void
+mdp5_wb_connector_atomic_commit(struct drm_connector *connector,
+		struct drm_writeback_job *job)
+{
+	struct msm_drm_private *priv = connector->dev->dev_private;
+	struct mdp5_kms *mdp5_kms = to_mdp5_kms(to_mdp_kms(priv->kms));
+	struct drm_connector_state *conn_state = connector->state;
+	struct drm_writeback_connector *wb_conn = to_wb_connector(connector);
+	struct mdp5_crtc_state *mdp5_crtc_state =
+		to_mdp5_crtc_state(wb_conn->encoder.crtc->state);
+	struct mdp5_wb_connector *mdp5_wb = to_mdp5_wb_connector(wb_conn);
+	struct drm_framebuffer *fb = job->fb;
+	struct drm_format_name_buf format_name;
+	const struct mdp_format *fmt =
+		to_mdp_format(mdp_get_format(priv->kms, fb->format->format));
+	u32 ystride0, ystride1, outsize;
+	u32 dst_format, pattern, opmode = 0;
+
+	DBG("wb[%u]: kick writeback %ux%u@%s", mdp5_wb->id,
+		fb->width, fb->height,
+		drm_get_format_name(fb->format->format, &format_name));
+
+	/* queue job before anything that can trigger completion irq */
+	drm_writeback_queue_job(wb_conn, job);
+	conn_state->writeback_job = NULL;
+
+	mdp_irq_register(&mdp5_kms->base, &mdp5_wb->wb_done);
+
+	if (MDP_FORMAT_IS_YUV(fmt)) {
+		wb_csc_setup(mdp5_kms, mdp5_wb->id,
+			mdp_get_default_csc_cfg(CSC_RGB2YUV));
+
+		opmode |= MDP5_WB_DST_OP_MODE_CSC_EN |
+			MDP5_WB_DST_OP_MODE_CSC_SRC_DATA_FORMAT(DATA_FORMAT_RGB) |
+			MDP5_WB_DST_OP_MODE_CSC_DST_DATA_FORMAT(DATA_FORMAT_YUV);
+
+		switch (fmt->chroma_sample) {
+		case CHROMA_420:
+		case CHROMA_H2V1:
+			opmode |= MDP5_WB_DST_OP_MODE_CHROMA_DWN_SAMPLE_EN;
+			break;
+		case CHROMA_H1V2:
+		default:
+			WARN(1, "unsupported wb chroma samp=%d\n",
+				fmt->chroma_sample);
+			return;
+		}
+	}
+
+	dst_format = MDP5_WB_DST_FORMAT_DST_CHROMA_SAMP(fmt->chroma_sample) |
+		MDP5_WB_DST_FORMAT_WRITE_PLANES(fmt->fetch_type) |
+		MDP5_WB_DST_FORMAT_DSTC3_OUT(fmt->bpc_a) |
+		MDP5_WB_DST_FORMAT_DSTC2_OUT(fmt->bpc_r) |
+		MDP5_WB_DST_FORMAT_DSTC1_OUT(fmt->bpc_b) |
+		MDP5_WB_DST_FORMAT_DSTC0_OUT(fmt->bpc_g) |
+		COND(fmt->unpack_tight, MDP5_WB_DST_FORMAT_PACK_TIGHT) |
+		MDP5_WB_DST_FORMAT_PACK_COUNT(fmt->unpack_count - 1) |
+		MDP5_WB_DST_FORMAT_DST_BPP(fmt->cpp - 1);
+
+	if (fmt->bpc_a || fmt->alpha_enable) {
+		dst_format |= MDP5_WB_DST_FORMAT_DSTC3_EN;
+		if (!fmt->alpha_enable)
+			dst_format |= MDP5_WB_DST_FORMAT_DST_ALPHA_X;
+	}
+
+	pattern = MDP5_WB_DST_PACK_PATTERN_ELEMENT3(fmt->unpack[3]) |
+		MDP5_WB_DST_PACK_PATTERN_ELEMENT2(fmt->unpack[2]) |
+		MDP5_WB_DST_PACK_PATTERN_ELEMENT1(fmt->unpack[1]) |
+		MDP5_WB_DST_PACK_PATTERN_ELEMENT0(fmt->unpack[0]);
+
+	ystride0 = MDP5_WB_DST_YSTRIDE0_DST0_YSTRIDE(fb->pitches[0]) |
+		MDP5_WB_DST_YSTRIDE0_DST1_YSTRIDE(fb->pitches[1]);
+	ystride1 = MDP5_WB_DST_YSTRIDE1_DST2_YSTRIDE(fb->pitches[2]) |
+		MDP5_WB_DST_YSTRIDE1_DST3_YSTRIDE(fb->pitches[3]);
+
+	/* get the output resolution from WB device */
+	outsize = MDP5_WB_OUT_SIZE_DST_H(fb->height) |
+		MDP5_WB_OUT_SIZE_DST_W(fb->width);
+
+	mdp5_write(mdp5_kms, REG_MDP5_WB_ALPHA_X_VALUE(mdp5_wb->id), 0xff);
+	mdp5_write(mdp5_kms, REG_MDP5_WB_DST_FORMAT(mdp5_wb->id), dst_format);
+	mdp5_write(mdp5_kms, REG_MDP5_WB_DST_OP_MODE(mdp5_wb->id), opmode);
+	mdp5_write(mdp5_kms, REG_MDP5_WB_DST_PACK_PATTERN(mdp5_wb->id), pattern);
+	mdp5_write(mdp5_kms, REG_MDP5_WB_DST_YSTRIDE0(mdp5_wb->id), ystride0);
+	mdp5_write(mdp5_kms, REG_MDP5_WB_DST_YSTRIDE1(mdp5_wb->id), ystride1);
+	mdp5_write(mdp5_kms, REG_MDP5_WB_OUT_SIZE(mdp5_wb->id), outsize);
+
+	mdp5_crtc_set_pipeline(wb_conn->encoder.crtc);
+
+	mdp5_write(mdp5_kms, REG_MDP5_WB_DST0_ADDR(mdp5_wb->id),
+		msm_framebuffer_iova(fb, priv->kms->aspace, 0));
+	mdp5_write(mdp5_kms, REG_MDP5_WB_DST1_ADDR(mdp5_wb->id),
+		msm_framebuffer_iova(fb, priv->kms->aspace, 1));
+	mdp5_write(mdp5_kms, REG_MDP5_WB_DST2_ADDR(mdp5_wb->id),
+		msm_framebuffer_iova(fb, priv->kms->aspace, 2));
+	mdp5_write(mdp5_kms, REG_MDP5_WB_DST3_ADDR(mdp5_wb->id),
+		msm_framebuffer_iova(fb, priv->kms->aspace, 3));
+
+	/* Notify ctl that wb buffer is ready to trigger start */
+	mdp5_ctl_commit(mdp5_wb->ctl, &mdp5_crtc_state->pipeline,
+		MDP5_CTL_FLUSH_WB, true);
+
+	mdp5_ctl_set_encoder_state(mdp5_wb->ctl,
+		&mdp5_crtc_state->pipeline, true);
+}
+
+static void mdp5_wb_done_irq(struct mdp_irq *irq, uint32_t irqstatus)
+{
+	struct mdp5_wb_connector *mdp5_wb =
+		container_of(irq, struct mdp5_wb_connector, wb_done);
+	struct mdp5_crtc_state *mdp5_crtc_state =
+		to_mdp5_crtc_state(mdp5_wb->base.encoder.crtc->state);
+	struct msm_drm_private *priv = mdp5_wb->base.base.dev->dev_private;
+
+	mdp_irq_unregister(to_mdp_kms(priv->kms), &mdp5_wb->wb_done);
+
+	mdp5_ctl_set_encoder_state(mdp5_wb->ctl,
+		&mdp5_crtc_state->pipeline, false);
+
+	drm_writeback_signal_completion(&mdp5_wb->base, 0);
+}
+
+static const struct drm_encoder_helper_funcs mdp5_wb_encoder_helper_funcs = {
+	.atomic_check = mdp5_wb_encoder_atomic_check,
+};
+
+struct drm_writeback_connector *
+mdp5_wb_connector_init(struct drm_device *dev, struct mdp5_ctl *ctl,
+		unsigned wb_id)
+{
+	struct drm_connector *connector = NULL;
+	struct mdp5_wb_connector *mdp5_wb;
+
+	mdp5_wb = kzalloc(sizeof(*mdp5_wb), GFP_KERNEL);
+	if (!mdp5_wb)
+		return ERR_PTR(-ENOMEM);
+
+	mdp5_wb->id = wb_id;
+	mdp5_wb->ctl = ctl;
+
+	/* construct a dummy intf for WB: */
+// TODO un-inline this (and also in interface_init())
+	mdp5_wb->intf = kzalloc(sizeof(*mdp5_wb->intf), GFP_KERNEL);
+	mdp5_wb->intf->num = -1;
+	mdp5_wb->intf->type = INTF_WB;
+	mdp5_wb->intf->mode = MDP5_INTF_WB_MODE_LINE;
+	mdp5_wb->intf->idx = -1;
+
+	mdp5_wb->wb_done.irq = mdp5_wb_done_irq;
+// TODO just register for all wb irq's until I figure out the mapping..
+	mdp5_wb->wb_done.irqmask = MDP5_IRQ_WB_0_DONE | MDP5_IRQ_WB_1_DONE | MDP5_IRQ_WB_2_DONE;
+
+	connector = &mdp5_wb->base.base;
+
+	drm_connector_helper_add(connector, &mdp5_wb_connector_helper_funcs);
+
+	mdp5_wb->nformats = mdp_get_formats(mdp5_wb->formats,
+		ARRAY_SIZE(mdp5_wb->formats), false);
+
+	drm_writeback_connector_init(dev,
+		&mdp5_wb->base,
+		&mdp5_wb_connector_funcs,
+		&mdp5_wb_encoder_helper_funcs,
+		mdp5_wb->formats,
+		mdp5_wb->nformats);
+
+	connector->interlace_allowed = 0;
+	connector->doublescan_allowed = 0;
+
+	return &mdp5_wb->base;
+}
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 7a03a9489708..422f524f7562 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -741,7 +741,7 @@ static void dsi_intr_ctrl(struct msm_dsi_host *msm_host, u32 mask, int enable)
 	else
 		intr &= ~mask;
 
-	DBG("intr=%x enable=%d", intr, enable);
+	VERB("intr=%x enable=%d", intr, enable);
 
 	dsi_write(msm_host, REG_DSI_INTR_CTRL, intr);
 	spin_unlock_irqrestore(&msm_host->intr_lock, flags);
@@ -1465,7 +1465,7 @@ static irqreturn_t dsi_host_irq(int irq, void *ptr)
 	dsi_write(msm_host, REG_DSI_INTR_CTRL, isr);
 	spin_unlock_irqrestore(&msm_host->intr_lock, flags);
 
-	DBG("isr=0x%x, id=%d", isr, msm_host->id);
+	VERB("isr=0x%x, id=%d", isr, msm_host->id);
 
 	if (isr & DSI_IRQ_ERROR)
 		dsi_error(msm_host);
-- 
2.14.3