[PATCH v4 1/5] drm/msm/dsi: support DSC configurations with slice_per_pkt > 1

[Jun Nie <jun.nie@linaro.org>]

Some panels require multiple slice to be sent in a single DSC packet. And
this feature is a must for specific panels, such as Sharp ls026b3sa06. Add
a dsc_slice_per_pkt member into struct drm_dsc_config and support the
feature in msm mdss driver.

Co-developed-by: Jonathan Marek <jonathan@marek.ca>
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Signed-off-by: Jun Nie <jun.nie@linaro.org>
---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 23 ++++++++---------------
 include/drm/display/drm_dsc.h      |  7 +++++++
 2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 53ff23f4f68ab..d14b6e41dcd90 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -166,6 +166,7 @@ struct msm_dsi_host {
 
 	struct drm_display_mode *mode;
 	struct drm_dsc_config *dsc;
+	unsigned int dsc_slice_per_pkt;
 
 	/* connected device info */
 	unsigned int channel;
@@ -938,17 +939,10 @@ static void dsi_update_dsc_timing(struct msm_dsi_host *msm_host, bool is_cmd_mod
 	slice_per_intf = dsc->slice_count;
 
 	total_bytes_per_intf = dsc->slice_chunk_size * slice_per_intf;
-	bytes_per_pkt = dsc->slice_chunk_size; /* * slice_per_pkt; */
+	bytes_per_pkt = dsc->slice_chunk_size * msm_host->dsc_slice_per_pkt;
 
 	eol_byte_num = total_bytes_per_intf % 3;
-
-	/*
-	 * Typically, pkt_per_line = slice_per_intf * slice_per_pkt.
-	 *
-	 * Since the current driver only supports slice_per_pkt = 1,
-	 * pkt_per_line will be equal to slice per intf for now.
-	 */
-	pkt_per_line = slice_per_intf;
+	pkt_per_line = slice_per_intf / msm_host->dsc_slice_per_pkt;
 
 	if (is_cmd_mode) /* packet data type */
 		reg = DSI_COMMAND_COMPRESSION_MODE_CTRL_STREAM0_DATATYPE(MIPI_DSI_DCS_LONG_WRITE);
@@ -1104,12 +1098,8 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
 		else
 			/*
 			 * When DSC is enabled, WC = slice_chunk_size * slice_per_pkt + 1.
-			 * Currently, the driver only supports default value of slice_per_pkt = 1
-			 *
-			 * TODO: Expand mipi_dsi_device struct to hold slice_per_pkt info
-			 *       and adjust DSC math to account for slice_per_pkt.
 			 */
-			wc = msm_host->dsc->slice_chunk_size + 1;
+			wc = msm_host->dsc->slice_chunk_size * msm_host->dsc_slice_per_pkt + 1;
 
 		dsi_write(msm_host, REG_DSI_CMD_MDP_STREAM0_CTRL,
 			DSI_CMD_MDP_STREAM0_CTRL_WORD_COUNT(wc) |
@@ -1719,8 +1709,11 @@ static int dsi_host_attach(struct mipi_dsi_host *host,
 	msm_host->lanes = dsi->lanes;
 	msm_host->format = dsi->format;
 	msm_host->mode_flags = dsi->mode_flags;
-	if (dsi->dsc)
+	if (dsi->dsc) {
 		msm_host->dsc = dsi->dsc;
+		/* for backwards compatibility, assume 1 if not set */
+		msm_host->dsc_slice_per_pkt = dsi->dsc->dsc_slice_per_pkt ?: 1;
+	}
 
 	if (msm_host->format == MIPI_DSI_FMT_RGB101010) {
 		if (!msm_dsi_host_version_geq(msm_host, MSM_DSI_VER_MAJOR_6G,
diff --git a/include/drm/display/drm_dsc.h b/include/drm/display/drm_dsc.h
index bbbe7438473d3..c522ab3d71853 100644
--- a/include/drm/display/drm_dsc.h
+++ b/include/drm/display/drm_dsc.h
@@ -267,6 +267,13 @@ struct drm_dsc_config {
 	 * Offset adjustment for second line in Native 4:2:0 mode
 	 */
 	u16 second_line_offset_adj;
+
+	/**
+	 * @dsc_slice_per_pkt:
+	 * Number of DSC slices to be sent in a single packet. This is not
+	 * part of DSC standard, and only used in some DSI panels so far.
+	 */
+	unsigned int dsc_slice_per_pkt;
 };
 
 /**

-- 
2.43.0