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 <[email protected]>
Signed-off-by: Jonathan Marek <[email protected]>
Signed-off-by: Jun Nie <[email protected]>
---
 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

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