linux-kernel - [PATCH v4 4/4] drm/msm/dsi: Enable widebus for DSI

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Message-ID: <20230822-add-widebus-support-v4-4-9dc86083d6ea@quicinc.com>
Date:   Tue, 22 Aug 2023 10:42:07 -0700
From:   Jessica Zhang <quic_jesszhan@...cinc.com>
To:     Rob Clark <robdclark@...il.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>,
        "Daniel Vetter" <daniel@...ll.ch>
CC:     <quic_abhinavk@...cinc.com>, <linux-arm-msm@...r.kernel.org>,
        <dri-devel@...ts.freedesktop.org>,
        <freedreno@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
        Jessica Zhang <quic_jesszhan@...cinc.com>
Subject: [PATCH v4 4/4] drm/msm/dsi: Enable widebus for DSI

DSI 6G v2.5.x+ supports a data-bus widen mode that allows DSI to send
48 bits of compressed data instead of 24.

Enable this mode whenever DSC is enabled for supported chipsets.

Signed-off-by: Jessica Zhang <quic_jesszhan@...cinc.com>
---
 drivers/gpu/drm/msm/dsi/dsi.c      |  2 +-
 drivers/gpu/drm/msm/dsi/dsi.h      |  1 +
 drivers/gpu/drm/msm/dsi/dsi_host.c | 31 +++++++++++++++++++++++++++----
 3 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c
index 4cf424b3509f..7327bfc06a84 100644
--- a/drivers/gpu/drm/msm/dsi/dsi.c
+++ b/drivers/gpu/drm/msm/dsi/dsi.c
@@ -19,7 +19,7 @@ struct drm_dsc_config *msm_dsi_get_dsc_config(struct msm_dsi *msm_dsi)
 
 bool msm_dsi_wide_bus_enabled(struct msm_dsi *msm_dsi)
 {
-	return false;
+	return msm_dsi_host_is_widebus_enabled(msm_dsi->host);
 }
 
 static int dsi_get_phy(struct msm_dsi *msm_dsi)
diff --git a/drivers/gpu/drm/msm/dsi/dsi.h b/drivers/gpu/drm/msm/dsi/dsi.h
index bd3763a5d723..a557d2c1aaff 100644
--- a/drivers/gpu/drm/msm/dsi/dsi.h
+++ b/drivers/gpu/drm/msm/dsi/dsi.h
@@ -134,6 +134,7 @@ int dsi_calc_clk_rate_6g(struct msm_dsi_host *msm_host, bool is_bonded_dsi);
 void msm_dsi_host_snapshot(struct msm_disp_state *disp_state, struct mipi_dsi_host *host);
 void msm_dsi_host_test_pattern_en(struct mipi_dsi_host *host);
 struct drm_dsc_config *msm_dsi_host_get_dsc_config(struct mipi_dsi_host *host);
+bool msm_dsi_host_is_widebus_enabled(struct mipi_dsi_host *host);
 
 /* dsi phy */
 struct msm_dsi_phy;
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 645927214871..267c7fda8854 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -710,6 +710,15 @@ static void dsi_ctrl_disable(struct msm_dsi_host *msm_host)
 	dsi_write(msm_host, REG_DSI_CTRL, 0);
 }
 
+bool msm_dsi_host_is_widebus_enabled(struct mipi_dsi_host *host)
+{
+	struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
+
+	return msm_host->dsc &&
+		(msm_host->cfg_hnd->major == MSM_DSI_VER_MAJOR_6G &&
+		 msm_host->cfg_hnd->minor >= MSM_DSI_6G_VER_MINOR_V2_5_0);
+}
+
 static void dsi_ctrl_enable(struct msm_dsi_host *msm_host,
 			struct msm_dsi_phy_shared_timings *phy_shared_timings, struct msm_dsi_phy *phy)
 {
@@ -753,10 +762,16 @@ static void dsi_ctrl_enable(struct msm_dsi_host *msm_host,
 		data |= DSI_CMD_CFG1_INSERT_DCS_COMMAND;
 		dsi_write(msm_host, REG_DSI_CMD_CFG1, data);
 
-		if (msm_host->cfg_hnd->major == MSM_DSI_VER_MAJOR_6G &&
-		    msm_host->cfg_hnd->minor >= MSM_DSI_6G_VER_MINOR_V1_3) {
+		if (cfg_hnd->major == MSM_DSI_VER_MAJOR_6G) {
 			data = dsi_read(msm_host, REG_DSI_CMD_MODE_MDP_CTRL2);
-			data |= DSI_CMD_MODE_MDP_CTRL2_BURST_MODE;
+
+			if (cfg_hnd->minor >= MSM_DSI_6G_VER_MINOR_V1_3)
+				data |= DSI_CMD_MODE_MDP_CTRL2_BURST_MODE;
+
+			/* TODO: Allow for video-mode support once tested/fixed */
+			if (msm_dsi_host_is_widebus_enabled(&msm_host->base))
+				data |= DSI_CMD_MODE_MDP_CTRL2_DATABUS_WIDEN;
+
 			dsi_write(msm_host, REG_DSI_CMD_MODE_MDP_CTRL2, data);
 		}
 	}
@@ -894,6 +909,7 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
 	u32 hdisplay = mode->hdisplay;
 	u32 wc;
 	int ret;
+	bool widebus_enabled = msm_dsi_host_is_widebus_enabled(&msm_host->base);
 
 	DBG("");
 
@@ -914,6 +930,7 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
 
 	if (msm_host->dsc) {
 		struct drm_dsc_config *dsc = msm_host->dsc;
+		u32 bytes_per_pclk;
 
 		/* update dsc params with timing params */
 		if (!dsc || !mode->hdisplay || !mode->vdisplay) {
@@ -937,7 +954,13 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
 		 * pulse width same
 		 */
 		h_total -= hdisplay;
-		hdisplay = DIV_ROUND_UP(msm_dsc_get_bytes_per_line(msm_host->dsc), 3);
+		if (widebus_enabled && !(msm_host->mode_flags & MIPI_DSI_MODE_VIDEO))
+			bytes_per_pclk = 6;
+		else
+			bytes_per_pclk = 3;
+
+		hdisplay = DIV_ROUND_UP(msm_dsc_get_bytes_per_line(msm_host->dsc), bytes_per_pclk);
+
 		h_total += hdisplay;
 		ha_end = ha_start + hdisplay;
 	}

-- 
2.42.0