Re: [REPOST PATCH v4 01/13] drm/msm/dsi: add support for dsc data

Dmitry Baryshkov
2022-02-21T02:17:32Z

On 10/02/2022 13:34, Vinod Koul wrote:
> Display Stream Compression (DSC) parameters need to be calculated. Add
> helpers and struct msm_display_dsc_config in msm_drv for this
> msm_display_dsc_config uses drm_dsc_config for DSC parameters.
>
> Signed-off-by: Vinod Koul <vkoul@kernel.org>
> ---
> drivers/gpu/drm/msm/dsi/dsi_host.c | 132 +++++++++++++++++++++++++++++
> drivers/gpu/drm/msm/msm_drv.h | 15 ++++
> 2 files changed, 147 insertions(+)
>
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 6b3ced4aaaf5..27553194f9fa 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -31,6 +31,8 @@
>
> #define DSI_RESET_TOGGLE_DELAY_MS 20
>
> +static int dsi_populate_dsc_params(struct msm_display_dsc_config *dsc);
> +
> static int dsi_get_version(const void __iomem *base, u32 *major, u32 *minor)
> {
> u32 ver;
> @@ -157,6 +159,7 @@ struct msm_dsi_host {
> struct regmap *sfpb;
>
> struct drm_display_mode *mode;
> + struct msm_display_dsc_config *dsc;
>
> /* connected device info */
> struct device_node *device_node;
> @@ -1718,6 +1721,135 @@ static int dsi_host_parse_lane_data(struct msm_dsi_host *msm_host,
> return -EINVAL;
> }
>
> +static u32 dsi_dsc_rc_buf_thresh[DSC_NUM_BUF_RANGES - 1] = {
> + 0x0e, 0x1c, 0x2a, 0x38, 0x46, 0x54, 0x62,
> + 0x69, 0x70, 0x77, 0x79, 0x7b, 0x7d, 0x7e
> +};
> +
> +/* only 8bpc, 8bpp added */
> +static char min_qp[DSC_NUM_BUF_RANGES] = {
> + 0, 0, 1, 1, 3, 3, 3, 3, 3, 3, 5, 5, 5, 7, 13
> +};
> +
> +static char max_qp[DSC_NUM_BUF_RANGES] = {
> + 4, 4, 5, 6, 7, 7, 7, 8, 9, 10, 11, 12, 13, 13, 15
> +};
> +
> +static char bpg_offset[DSC_NUM_BUF_RANGES] = {
> + 2, 0, 0, -2, -4, -6, -8, -8, -8, -10, -10, -12, -12, -12, -12
> +};
> +
> +static int dsi_populate_dsc_params(struct msm_display_dsc_config *dsc)
> +{
> + int mux_words_size;
> + int groups_per_line, groups_total;
> + int min_rate_buffer_size;
> + int hrd_delay;
> + int pre_num_extra_mux_bits, num_extra_mux_bits;
> + int slice_bits;
> + int target_bpp_x16;
> + int data;
> + int final_value, final_scale;
> + int i;
> +
> + dsc->drm->rc_model_size = 8192;
> + dsc->drm->first_line_bpg_offset = 12;
> + dsc->drm->rc_edge_factor = 6;
> + dsc->drm->rc_tgt_offset_high = 3;
> + dsc->drm->rc_tgt_offset_low = 3;
> + dsc->drm->simple_422 = 0;
> + dsc->drm->convert_rgb = 1;
> + dsc->drm->vbr_enable = 0;
> +
> + /* handle only bpp = bpc = 8 */
> + for (i = 0; i < DSC_NUM_BUF_RANGES - 1 ; i++)
> + dsc->drm->rc_buf_thresh[i] = dsi_dsc_rc_buf_thresh[i];
> +
> + for (i = 0; i < DSC_NUM_BUF_RANGES; i++) {
> + dsc->drm->rc_range_params[i].range_min_qp = min_qp[i];
> + dsc->drm->rc_range_params[i].range_max_qp = max_qp[i];
> + dsc->drm->rc_range_params[i].range_bpg_offset = bpg_offset[i];
> + }
> +
> + dsc->drm->initial_offset = 6144; /* Not bpp 12 */
> + if (dsc->drm->bits_per_pixel != 8)
> + dsc->drm->initial_offset = 2048; /* bpp = 12 */
> +
> + mux_words_size = 48; /* bpc == 8/10 */
> + if (dsc->drm->bits_per_component == 12)
> + mux_words_size = 64;
> +
> + dsc->drm->initial_xmit_delay = 512;
> + dsc->drm->initial_scale_value = 32;
> + dsc->drm->first_line_bpg_offset = 12;
> + dsc->drm->line_buf_depth = dsc->drm->bits_per_component + 1;
> +
> + /* bpc 8 */
> + dsc->drm->flatness_min_qp = 3;
> + dsc->drm->flatness_max_qp = 12;
> + dsc->det_thresh_flatness = 7 + 2 * (dsc->drm->bits_per_component - 8);
> + dsc->drm->rc_quant_incr_limit0 = 11;
> + dsc->drm->rc_quant_incr_limit1 = 11;
> + dsc->drm->mux_word_size = DSC_MUX_WORD_SIZE_8_10_BPC;
> +
> + /* FIXME: need to call drm_dsc_compute_rc_parameters() so that rest of
> + * params are calculated
> + */
> + dsc->slice_last_group_size = 3 - (dsc->drm->slice_width % 3);
> + groups_per_line = DIV_ROUND_UP(dsc->drm->slice_width, 3);
> + dsc->drm->slice_chunk_size = dsc->drm->slice_width * dsc->drm->bits_per_pixel / 8;
> + if ((dsc->drm->slice_width * dsc->drm->bits_per_pixel) % 8)
> + dsc->drm->slice_chunk_size++;
> +
> + /* rbs-min */
> + min_rate_buffer_size = dsc->drm->rc_model_size - dsc->drm->initial_offset +
> + dsc->drm->initial_xmit_delay * dsc->drm->bits_per_pixel +
> + groups_per_line * dsc->drm->first_line_bpg_offset;
> +
> + hrd_delay = DIV_ROUND_UP(min_rate_buffer_size, dsc->drm->bits_per_pixel);
> +
> + dsc->drm->initial_dec_delay = hrd_delay - dsc->drm->initial_xmit_delay;
> +
> + dsc->drm->initial_scale_value = 8 * dsc->drm->rc_model_size /
> + (dsc->drm->rc_model_size - dsc->drm->initial_offset);
> +
> + slice_bits = 8 * dsc->drm->slice_chunk_size * dsc->drm->slice_height;
> +
> + groups_total = groups_per_line * dsc->drm->slice_height;
> +
> + data = dsc->drm->first_line_bpg_offset * 2048;
> +
> + dsc->drm->nfl_bpg_offset = DIV_ROUND_UP(data, (dsc->drm->slice_height - 1));
> +
> + pre_num_extra_mux_bits = 3 * (mux_words_size + (4 * dsc->drm->bits_per_component + 4) - 2);
> +
> + num_extra_mux_bits = pre_num_extra_mux_bits - (mux_words_size -
> + ((slice_bits - pre_num_extra_mux_bits) % mux_words_size));
> +
> + data = 2048 * (dsc->drm->rc_model_size - dsc->drm->initial_offset + num_extra_mux_bits);
> + dsc->drm->slice_bpg_offset = DIV_ROUND_UP(data, groups_total);
> +
> + /* bpp * 16 + 0.5 */
> + data = dsc->drm->bits_per_pixel * 16;
> + data *= 2;
> + data++;
> + data /= 2;
> + target_bpp_x16 = data;
> +
> + data = (dsc->drm->initial_xmit_delay * target_bpp_x16) / 16;
> + final_value = dsc->drm->rc_model_size - data + num_extra_mux_bits;
> + dsc->drm->final_offset = final_value;
> +
> + final_scale = 8 * dsc->drm->rc_model_size / (dsc->drm->rc_model_size - final_value);
> +
> + data = (final_scale - 9) * (dsc->drm->nfl_bpg_offset + dsc->drm->slice_bpg_offset);
> + dsc->drm->scale_increment_interval = (2048 * dsc->drm->final_offset) / data;
> +
> + dsc->drm->scale_decrement_interval = groups_per_line / (dsc->drm->initial_scale_value - 8);
> +
> + return 0;
> +}
> +
> static int dsi_host_parse_dt(struct msm_dsi_host *msm_host)
> {
> struct device *dev = &msm_host->pdev->dev;
> diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
> index d7574e6bd4e4..384f9bad4760 100644
> --- a/drivers/gpu/drm/msm/msm_drv.h
> +++ b/drivers/gpu/drm/msm/msm_drv.h
> @@ -30,6 +30,7 @@
> #include <drm/drm_plane_helper.h>
> #include <drm/drm_probe_helper.h>
> #include <drm/drm_fb_helper.h>
> +#include <drm/drm_dsc.h>
> #include <drm/msm_drm.h>
> #include <drm/drm_gem.h>
>
> @@ -134,6 +135,20 @@ struct msm_drm_thread {
> struct kthread_worker *worker;
> };
>
> +/* DSC config */
> +struct msm_display_dsc_config {
> + struct drm_dsc_config *drm;
> +
> + u32 initial_lines;
> + u32 pkt_per_line;
> + u32 bytes_in_slice;
> + u32 bytes_per_pkt;
> + u32 eol_byte_num;
> + u32 pclk_per_line;
> + u32 slice_last_group_size;
> + u32 det_thresh_flatness;

I have been looking throught the dsc params calculation. And it looks
like this struct is not necessary at all.

inital_lines can be passed to dpu_encoder_dsc_pipe_cfg() /
hw_dsc->ops.dsc_config() directly.

slice_last_group_size and det_thresh_flatness can be calculated in
dpu_hw_dsc_config() directly. And the rest is only used in
dsi_timing_setup(), where they are calculated an immediately used to set
the hardware. Let's probably drop it, unless there is a good reason to
have it?

> +};
> +
> struct msm_drm_private {
>
> struct drm_device *dev;

--
With best wishes
Dmitry