Re: [PATCH v3 12/13] drm/msm/dsi: Add support for DSC configuration

From: Dmitry Baryshkov
Date: Wed Nov 24 2021 - 11:22:01 EST

On 16/11/2021 09:22, Vinod Koul wrote:
When DSC is enabled, we need to configure DSI registers accordingly and
configure the respective stream compression registers.

Add support to calculate the register setting based on DSC params and
timing information and configure these registers.

Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
---
drivers/gpu/drm/msm/dsi/dsi.xml.h | 10 +++
drivers/gpu/drm/msm/dsi/dsi_host.c | 113 ++++++++++++++++++++++++++++-
2 files changed, 122 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi.xml.h b/drivers/gpu/drm/msm/dsi/dsi.xml.h
index 49b551ad1bff..c1c85df58c4b 100644
--- a/drivers/gpu/drm/msm/dsi/dsi.xml.h
+++ b/drivers/gpu/drm/msm/dsi/dsi.xml.h
@@ -706,4 +706,14 @@ static inline uint32_t DSI_VERSION_MAJOR(uint32_t val)
#define REG_DSI_CPHY_MODE_CTRL 0x000002d4
+#define REG_DSI_VIDEO_COMPRESSION_MODE_CTRL 0x0000029c
+
+#define REG_DSI_VIDEO_COMPRESSION_MODE_CTRL2 0x000002a0
+
+#define REG_DSI_COMMAND_COMPRESSION_MODE_CTRL 0x000002a4
+
+#define REG_DSI_COMMAND_COMPRESSION_MODE_CTRL2 0x000002a8
+
+#define REG_DSI_COMMAND_COMPRESSION_MODE_CTRL3 0x000002ac
+
#endif /* DSI_XML */
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 31d385d8d834..2c14c36f0b3d 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -908,6 +908,20 @@ static void dsi_ctrl_config(struct msm_dsi_host *msm_host, bool enable,
dsi_write(msm_host, REG_DSI_CPHY_MODE_CTRL, BIT(0));
}
+static int dsi_dsc_update_pic_dim(struct msm_display_dsc_config *dsc,
+ int pic_width, int pic_height)
+{
+ if (!dsc || !pic_width || !pic_height) {
+ pr_err("DSI: invalid input: pic_width: %d pic_height: %d\n", pic_width, pic_height);
+ return -EINVAL;
+ }
+
+ dsc->drm->pic_width = pic_width;
+ dsc->drm->pic_height = pic_height;
+
+ return 0;
+}
+
static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
{
struct drm_display_mode *mode = msm_host->mode;
@@ -940,7 +954,68 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
hdisplay /= 2;
}
+ if (msm_host->dsc) {
+ struct msm_display_dsc_config *dsc = msm_host->dsc;
+
+ /* update dsc params with timing params */
+ dsi_dsc_update_pic_dim(dsc, mode->hdisplay, mode->vdisplay);
+ DBG("Mode Width- %d x Height %d\n", dsc->drm->pic_width, dsc->drm->pic_height);
+
+ /* we do the calculations for dsc parameters here so that
+ * panel can use these parameters
+ */
+ dsi_populate_dsc_params(dsc);
+
+ /* Divide the display by 3 but keep back/font porch and
+ * pulse width same
+ */
+ h_total -= hdisplay;
+ hdisplay /= 3;
+ h_total += hdisplay;
+ ha_end = ha_start + hdisplay;
+ }
+
if (msm_host->mode_flags & MIPI_DSI_MODE_VIDEO) {
+ if (msm_host->dsc) {
+ struct msm_display_dsc_config *dsc = msm_host->dsc;
+ u32 reg, intf_width, slice_per_intf;
+ u32 total_bytes_per_intf;
+
+ /* first calculate dsc parameters and then program
+ * compress mode registers
+ */
+ intf_width = hdisplay;
+ slice_per_intf = DIV_ROUND_UP(intf_width, dsc->drm->slice_width);
+
+ dsc->drm->slice_count = 1;
+ dsc->bytes_in_slice = DIV_ROUND_UP(dsc->drm->slice_width * 8, 8);
+ total_bytes_per_intf = dsc->bytes_in_slice * slice_per_intf;
+
+ dsc->eol_byte_num = total_bytes_per_intf % 3;
+ dsc->pclk_per_line = DIV_ROUND_UP(total_bytes_per_intf, 3);
+ dsc->bytes_per_pkt = dsc->bytes_in_slice * dsc->drm->slice_count;
+ dsc->pkt_per_line = slice_per_intf / dsc->drm->slice_count;
+
+ reg = dsc->bytes_per_pkt << 16;
+ reg |= (0x0b << 8); /* dtype of compressed image */
+
+ /* pkt_per_line:
+ * 0 == 1 pkt
+ * 1 == 2 pkt
+ * 2 == 4 pkt
+ * 3 pkt is not supported
+ * above translates to ffs() - 1
+ */
+ reg |= (ffs(dsc->pkt_per_line) - 1) << 6;
+
+ dsc->eol_byte_num = total_bytes_per_intf % 3;
+ reg |= dsc->eol_byte_num << 4;
+ reg |= 1;
+
+ dsi_write(msm_host,
+ REG_DSI_VIDEO_COMPRESSION_MODE_CTRL, reg);
+ }
+
dsi_write(msm_host, REG_DSI_ACTIVE_H,
DSI_ACTIVE_H_START(ha_start) |
DSI_ACTIVE_H_END(ha_end));
@@ -959,8 +1034,40 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
DSI_ACTIVE_VSYNC_VPOS_START(vs_start) |
DSI_ACTIVE_VSYNC_VPOS_END(vs_end));
} else { /* command mode */
+ if (msm_host->dsc) {
+ struct msm_display_dsc_config *dsc = msm_host->dsc;
+ u32 reg, reg_ctrl, reg_ctrl2;
+ u32 slice_per_intf, bytes_in_slice, total_bytes_per_intf;
+
+ reg_ctrl = dsi_read(msm_host, REG_DSI_COMMAND_COMPRESSION_MODE_CTRL);
+ reg_ctrl2 = dsi_read(msm_host, REG_DSI_COMMAND_COMPRESSION_MODE_CTRL2);
+
+ slice_per_intf = DIV_ROUND_UP(hdisplay, dsc->drm->slice_width);
+ bytes_in_slice = DIV_ROUND_UP(dsc->drm->slice_width *
+ dsc->drm->bits_per_pixel, 8);
+ dsc->drm->slice_chunk_size = bytes_in_slice;
+ total_bytes_per_intf = dsc->bytes_in_slice * slice_per_intf;
+ dsc->pkt_per_line = slice_per_intf / dsc->drm->slice_count;
+
+ reg = 0x39 << 8;
+ reg |= ffs(dsc->pkt_per_line) << 6;
+
+ dsc->eol_byte_num = total_bytes_per_intf % 3;
+ reg |= dsc->eol_byte_num << 4;
+ reg |= 1;
+
+ reg_ctrl |= reg;
+ reg_ctrl2 |= bytes_in_slice;
+
+ dsi_write(msm_host, REG_DSI_COMMAND_COMPRESSION_MODE_CTRL, reg);
+ dsi_write(msm_host, REG_DSI_COMMAND_COMPRESSION_MODE_CTRL2, reg_ctrl2);
+ }
+
/* image data and 1 byte write_memory_start cmd */
- wc = hdisplay * dsi_get_bpp(msm_host->format) / 8 + 1;
+ if (!msm_host->dsc)
+ wc = hdisplay * dsi_get_bpp(msm_host->format) / 8 + 1;
+ else
+ wc = mode->hdisplay / 2 + 1;
dsi_write(msm_host, REG_DSI_CMD_MDP_STREAM0_CTRL,
DSI_CMD_MDP_STREAM0_CTRL_WORD_COUNT(wc) |
@@ -2051,9 +2158,13 @@ int msm_dsi_host_modeset_init(struct mipi_dsi_host *host,
{
struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
const struct msm_dsi_cfg_handler *cfg_hnd = msm_host->cfg_hnd;
+ struct msm_drm_private *priv;
int ret;
msm_host->dev = dev;
+ priv = dev->dev_private;
+ priv->dsc = msm_host->dsc;

I have been thinking about this piece. I highly dislike the priv->dsc field for multiple reasons.

Please correct me if I'm wrong, we use it for several reasons:
- to check if DSC is requested at all
- to store the dsc_mask

The DSC mask should be calculated basing on dpu_encoder_virt->hw_dsc[] values, so it can be removed from msm_display_dsc_config.

To check whether DSC is enabled, I'd suggest the following:

- Add use_dsc flag to struct msm_display_info.
This way it would be generic to all possible encoders which can use DSC.

- Add struct msm_dsi_has_dsc_panel() function.
It checks whether msm_host has ->dsc data. Feel free to change the name of the function to better suit your style.

- Call msm_dsi_has_dsc_panel() from _dpu_kms_initialize_dsi().
If DSC is requested, set info->use_dsc.

- In dpu_encoder_setup store use_dsc in struct dpu_encoder_virt() and use it later instead of checking priv->dsc.

WDYT?


+
ret = cfg_hnd->ops->tx_buf_alloc(msm_host, SZ_4K);
if (ret) {
pr_err("%s: alloc tx gem obj failed, %d\n", __func__, ret);



--
With best wishes
Dmitry