Re: [PATCH v2 13/19] drm/msm/dp: add VSC SDP support for YUV420 over DP

On Sat, 10 Feb 2024 at 20:50, Abhinav Kumar [off-list ref] wrote:

On 2/10/2024 10:14 AM, Abhinav Kumar wrote:

quoted

On 2/10/2024 2:09 AM, Dmitry Baryshkov wrote:

quoted

On Sat, 10 Feb 2024 at 03:52, Paloma Arellano
[off-list ref] wrote:

quoted

Add support to pack and send the VSC SDP packet for DP. This therefore
allows the transmision of format information to the sinks which is
needed for YUV420 support over DP.

Changes in v2:
         - Rename GENERIC0_SDPSIZE macro to GENERIC0_SDPSIZE_VALID
         - Remove dp_sdp from the dp_catalog struct since this data is
           being allocated at the point used
         - Create a new function in dp_utils to pack the VSC SDP data
           into a buffer
         - Create a new function that packs the SDP header bytes into a
           buffer. This function is made generic so that it can be
           utilized by dp_audio
           header bytes into a buffer
         - Create a new function in dp_utils that takes the packed
buffer
           and writes to the DP_GENERIC0_* registers
         - Split the dp_catalog_panel_config_vsc_sdp() function into two
           to disable/enable sending VSC SDP packets
         - Check the DP HW version using the original useage of
           dp_catalog_hw_revision() and correct the version checking
           logic
         - Rename dp_panel_setup_vsc_sdp() to
           dp_panel_setup_vsc_sdp_yuv_420() to explicitly state that
           currently VSC SDP is only being set up to support YUV420
modes

Signed-off-by: Paloma Arellano <redacted>
---
  drivers/gpu/drm/msm/dp/dp_catalog.c | 105 ++++++++++++++++++++++++++++
  drivers/gpu/drm/msm/dp/dp_catalog.h |   6 ++
  drivers/gpu/drm/msm/dp/dp_ctrl.c    |   4 ++
  drivers/gpu/drm/msm/dp/dp_panel.c   |  59 ++++++++++++++++
  drivers/gpu/drm/msm/dp/dp_reg.h     |   3 +
  drivers/gpu/drm/msm/dp/dp_utils.c   |  80 +++++++++++++++++++++
  drivers/gpu/drm/msm/dp/dp_utils.h   |   3 +
  7 files changed, 260 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c

b/drivers/gpu/drm/msm/dp/dp_catalog.c
index 5d84c089e520a..0f28a4897b7b7 100644

--- a/drivers/gpu/drm/msm/dp/dp_catalog.c
+++ b/drivers/gpu/drm/msm/dp/dp_catalog.c

@@ -901,6 +901,111 @@ int dp_catalog_panel_timing_cfg(struct

dp_catalog *dp_catalog)
         return 0;
  }

+static void dp_catalog_panel_send_vsc_sdp(struct dp_catalog
*dp_catalog, u32 *buffer)
+{
+       struct dp_catalog_private *catalog;
+
+       if (!dp_catalog) {
+               DRM_ERROR("invalid input\n");
+               return;
+       }
+
+       catalog = container_of(dp_catalog, struct dp_catalog_private,
dp_catalog);
+
+       dp_write_link(catalog, MMSS_DP_GENERIC0_0, buffer[0]);
+       dp_write_link(catalog, MMSS_DP_GENERIC0_1, buffer[1]);
+       dp_write_link(catalog, MMSS_DP_GENERIC0_2, buffer[2]);
+       dp_write_link(catalog, MMSS_DP_GENERIC0_3, buffer[3]);
+       dp_write_link(catalog, MMSS_DP_GENERIC0_4, buffer[4]);
+       dp_write_link(catalog, MMSS_DP_GENERIC0_5, buffer[5]);
+       dp_write_link(catalog, MMSS_DP_GENERIC0_6, buffer[6]);
+       dp_write_link(catalog, MMSS_DP_GENERIC0_7, buffer[7]);
+       dp_write_link(catalog, MMSS_DP_GENERIC0_8, buffer[8]);
+       dp_write_link(catalog, MMSS_DP_GENERIC0_9, buffer[9]);
+}
+
+static void dp_catalog_panel_update_sdp(struct dp_catalog *dp_catalog)
+{
+       struct dp_catalog_private *catalog;
+       u32 hw_revision;
+
+       catalog = container_of(dp_catalog, struct dp_catalog_private,
dp_catalog);
+
+       hw_revision = dp_catalog_hw_revision(dp_catalog);
+       if (hw_revision < DP_HW_VERSION_1_2 && hw_revision >=
DP_HW_VERSION_1_0) {
+               dp_write_link(catalog, MMSS_DP_SDP_CFG3, 0x01);
+               dp_write_link(catalog, MMSS_DP_SDP_CFG3, 0x00);
+       }
+}
+
+void dp_catalog_panel_enable_vsc_sdp(struct dp_catalog *dp_catalog,
u32 *gen_buffer)
+{
+       struct dp_catalog_private *catalog;
+       u32 cfg, cfg2, misc;
+
+       if (!dp_catalog) {
+               DRM_ERROR("invalid input\n");
+               return;
+       }
+
+       catalog = container_of(dp_catalog, struct dp_catalog_private,
dp_catalog);
+
+       cfg = dp_read_link(catalog, MMSS_DP_SDP_CFG);
+       cfg2 = dp_read_link(catalog, MMSS_DP_SDP_CFG2);
+       misc = dp_read_link(catalog, REG_DP_MISC1_MISC0);
+
+       cfg |= GEN0_SDP_EN;
+       dp_write_link(catalog, MMSS_DP_SDP_CFG, cfg);
+
+       cfg2 |= GENERIC0_SDPSIZE_VALID;
+       dp_write_link(catalog, MMSS_DP_SDP_CFG2, cfg2);
+
+       dp_catalog_panel_send_vsc_sdp(dp_catalog, gen_buffer);
+
+       /* indicates presence of VSC (BIT(6) of MISC1) */
+       misc |= DP_MISC1_VSC_SDP;
+
+       drm_dbg_dp(catalog->drm_dev, "vsc sdp enable=1\n");
+
+       pr_debug("misc settings = 0x%x\n", misc);
+       dp_write_link(catalog, REG_DP_MISC1_MISC0, misc);
+
+       dp_catalog_panel_update_sdp(dp_catalog);
+}
+
+void dp_catalog_panel_disable_vsc_sdp(struct dp_catalog *dp_catalog)
+{
+       struct dp_catalog_private *catalog;
+       u32 cfg, cfg2, misc;
+
+       if (!dp_catalog) {
+               DRM_ERROR("invalid input\n");
+               return;
+       }
+
+       catalog = container_of(dp_catalog, struct dp_catalog_private,
dp_catalog);
+
+       cfg = dp_read_link(catalog, MMSS_DP_SDP_CFG);
+       cfg2 = dp_read_link(catalog, MMSS_DP_SDP_CFG2);
+       misc = dp_read_link(catalog, REG_DP_MISC1_MISC0);
+
+       cfg &= ~GEN0_SDP_EN;
+       dp_write_link(catalog, MMSS_DP_SDP_CFG, cfg);
+
+       cfg2 &= ~GENERIC0_SDPSIZE_VALID;
+       dp_write_link(catalog, MMSS_DP_SDP_CFG2, cfg2);
+
+       /* switch back to MSA */
+       misc &= ~DP_MISC1_VSC_SDP;
+
+       drm_dbg_dp(catalog->drm_dev, "vsc sdp enable=0\n");
+
+       pr_debug("misc settings = 0x%x\n", misc);
+       dp_write_link(catalog, REG_DP_MISC1_MISC0, misc);
+
+       dp_catalog_panel_update_sdp(dp_catalog);
+}
+
  void dp_catalog_panel_tpg_enable(struct dp_catalog *dp_catalog,
                                 struct drm_display_mode *drm_mode)
  {

diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.h

b/drivers/gpu/drm/msm/dp/dp_catalog.h
index 6cb5e2a243de2..5b3a7ba40d55f 100644

--- a/drivers/gpu/drm/msm/dp/dp_catalog.h
+++ b/drivers/gpu/drm/msm/dp/dp_catalog.h

@@ -7,6 +7,7 @@
  #define _DP_CATALOG_H_

  #include <drm/drm_modes.h>
+#include <drm/display/drm_dp_helper.h>

  #include "dp_parser.h"
  #include "disp/msm_disp_snapshot.h"

@@ -30,6 +31,9 @@

  #define DP_AUX_CFG_MAX_VALUE_CNT 3

+#define DP_HW_VERSION_1_0      0x10000000
+#define DP_HW_VERSION_1_2      0x10020000
+
  /* PHY AUX config registers */
  enum dp_phy_aux_config_type {
         PHY_AUX_CFG0,

@@ -124,6 +128,8 @@ u32 dp_catalog_ctrl_read_phy_pattern(struct

dp_catalog *dp_catalog);

  /* DP Panel APIs */
  int dp_catalog_panel_timing_cfg(struct dp_catalog *dp_catalog);
+void dp_catalog_panel_enable_vsc_sdp(struct dp_catalog *dp_catalog,
u32 *gen_buffer);
+void dp_catalog_panel_disable_vsc_sdp(struct dp_catalog *dp_catalog);
  void dp_catalog_dump_regs(struct dp_catalog *dp_catalog);
  void dp_catalog_panel_tpg_enable(struct dp_catalog *dp_catalog,
                                 struct drm_display_mode *drm_mode);

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c

b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index 209cf2a35642f..beef86b1aaf81 100644

--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c

@@ -1952,6 +1952,8 @@ int dp_ctrl_off_link_stream(struct dp_ctrl

*dp_ctrl)
         dp_io = &ctrl->parser->io;
         phy = dp_io->phy;

+       dp_catalog_panel_disable_vsc_sdp(ctrl->catalog);
+
         /* set dongle to D3 (power off) mode */
         dp_link_psm_config(ctrl->link, &ctrl->panel->link_info, true);

@@ -2026,6 +2028,8 @@ int dp_ctrl_off(struct dp_ctrl *dp_ctrl)
         dp_io = &ctrl->parser->io;
         phy = dp_io->phy;

+       dp_catalog_panel_disable_vsc_sdp(ctrl->catalog);
+
         dp_catalog_ctrl_mainlink_ctrl(ctrl->catalog, false);

         dp_catalog_ctrl_reset(ctrl->catalog);

diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c

b/drivers/gpu/drm/msm/dp/dp_panel.c
index db1942794f1a4..82897edf25e0f 100644

--- a/drivers/gpu/drm/msm/dp/dp_panel.c
+++ b/drivers/gpu/drm/msm/dp/dp_panel.c

@@ -4,6 +4,7 @@
   */

  #include "dp_panel.h"
+#include "dp_utils.h"

  #include <drm/drm_connector.h>
  #include <drm/drm_edid.h>

@@ -281,6 +282,60 @@ void dp_panel_tpg_config(struct dp_panel

*dp_panel, bool enable)
         dp_catalog_panel_tpg_enable(catalog,
&panel->dp_panel.dp_mode.drm_mode);
  }

+static int dp_panel_setup_vsc_sdp_yuv_420(struct dp_panel *dp_panel)
+{
+       struct dp_catalog *catalog;
+       struct dp_panel_private *panel;
+       struct dp_display_mode *dp_mode;
+       struct dp_sdp_header sdp_header;
+       struct drm_dp_vsc_sdp vsc_sdp_data;
+       size_t buff_size;
+       u32 gen_buffer[10];
+       int rc = 0;
+
+       if (!dp_panel) {
+               DRM_ERROR("invalid input\n");
+               rc = -EINVAL;
+               return rc;
+       }
+
+       panel = container_of(dp_panel, struct dp_panel_private,
dp_panel);
+       catalog = panel->catalog;
+       dp_mode = &dp_panel->dp_mode;
+       buff_size = sizeof(gen_buffer);
+
+       memset(&sdp_header, 0, sizeof(sdp_header));
+       memset(&vsc_sdp_data, 0, sizeof(vsc_sdp_data));
+
+       /* VSC SDP header as per table 2-118 of DP 1.4 specification */
+       sdp_header.HB0 = 0x00;
+       sdp_header.HB1 = 0x07;
+       sdp_header.HB2 = 0x05;
+       sdp_header.HB3 = 0x13;

This should go to the packing function.

We can .... but ....

the header bytes can change based on the format. These values are
specific to YUV420. Thats why this part was kept outside of the generic
vsc sdp packing. Today we support only YUV420 VSC SDP so we can move it
but this was the reason.

These values can be set from the sdp_type, revision and length fields
of struct drm_dp_vsc_sdp.
The function intel_dp_vsc_sdp_pack() is pretty much close to what I had in mind.

quoted

quoted

quoted

+
+       /* VSC SDP Payload for DB16 */

Comments are useless more or less. The code fills generic information
structure which might or might not be packed to the data buffer.

quoted

+       vsc_sdp_data.pixelformat = DP_PIXELFORMAT_YUV420;
+       vsc_sdp_data.colorimetry = DP_COLORIMETRY_DEFAULT;
+
+       /* VSC SDP Payload for DB17 */
+       vsc_sdp_data.dynamic_range = DP_DYNAMIC_RANGE_CTA;
+
+       /* VSC SDP Payload for DB18 */
+       vsc_sdp_data.content_type = DP_CONTENT_TYPE_GRAPHICS;
+
+       vsc_sdp_data.bpc = dp_mode->bpp / 3;

Consider extracting intel_dp_compute_vsc_colorimetry() and using it.

intel_dp_compute_vsc_colorimetry() uses colorspace property to pick
YUV420, we do not.

Intel function also uses output_format, but it's true, it is full of
Intel specifics.

quoted

Right now, its a pure driver decision to use YUV420
when the mode is supported only in that format.

Also, many params are to be used within this function cached inside
intel_crtc_state . We will first need to make that API more generic to
be re-usable by others.

I think overall, if we want to have a generic packing across vendors, it
needs more work. I think one of us can take that up as a separate effort.

Ack, I agree here. I did only a quick glance over
intel_dp_compute_vsc_colorimetry function() beforehand.

quoted

quoted

quoted

+
+       rc = dp_utils_pack_vsc_sdp(&vsc_sdp_data, &sdp_header,
gen_buffer, buff_size);
+       if (rc) {
+               DRM_ERROR("unable to pack vsc sdp\n");
+               return rc;
+       }
+
+       dp_catalog_panel_enable_vsc_sdp(catalog, gen_buffer);
+
+       return rc;
+}
+
  void dp_panel_dump_regs(struct dp_panel *dp_panel)
  {
         struct dp_catalog *catalog;

@@ -344,6 +399,10 @@ int dp_panel_timing_cfg(struct dp_panel *dp_panel)
         catalog->dp_active = data;

         dp_catalog_panel_timing_cfg(catalog);
+
+       if (dp_panel->dp_mode.out_fmt_is_yuv_420)
+               dp_panel_setup_vsc_sdp_yuv_420(dp_panel);
+
         panel->panel_on = true;

         return 0;

diff --git a/drivers/gpu/drm/msm/dp/dp_reg.h

b/drivers/gpu/drm/msm/dp/dp_reg.h
index ea85a691e72b5..2983756c125cd 100644

--- a/drivers/gpu/drm/msm/dp/dp_reg.h
+++ b/drivers/gpu/drm/msm/dp/dp_reg.h

@@ -142,6 +142,7 @@
  #define DP_MISC0_SYNCHRONOUS_CLK               (0x00000001)
  #define DP_MISC0_COLORIMETRY_CFG_SHIFT         (0x00000001)
  #define DP_MISC0_TEST_BITS_DEPTH_SHIFT         (0x00000005)
+#define DP_MISC1_VSC_SDP                       (0x00004000)

  #define REG_DP_VALID_BOUNDARY                  (0x00000030)
  #define REG_DP_VALID_BOUNDARY_2                        (0x00000034)

@@ -201,9 +202,11 @@
  #define MMSS_DP_AUDIO_CTRL_RESET               (0x00000214)

  #define MMSS_DP_SDP_CFG                                (0x00000228)
+#define GEN0_SDP_EN                            (0x00020000)
  #define MMSS_DP_SDP_CFG2                       (0x0000022C)
  #define MMSS_DP_AUDIO_TIMESTAMP_0              (0x00000230)
  #define MMSS_DP_AUDIO_TIMESTAMP_1              (0x00000234)
+#define GENERIC0_SDPSIZE_VALID                 (0x00010000)

  #define MMSS_DP_AUDIO_STREAM_0                 (0x00000240)
  #define MMSS_DP_AUDIO_STREAM_1                 (0x00000244)

diff --git a/drivers/gpu/drm/msm/dp/dp_utils.c

b/drivers/gpu/drm/msm/dp/dp_utils.c
index 176d839906cec..05e0133eb50f3 100644

--- a/drivers/gpu/drm/msm/dp/dp_utils.c
+++ b/drivers/gpu/drm/msm/dp/dp_utils.c

@@ -4,6 +4,16 @@
   */

  #include <linux/types.h>
+#include <drm/display/drm_dp_helper.h>
+#include <drm/drm_print.h>
+
+#include "dp_utils.h"
+
+#define DP_GENERIC0_6_YUV_8_BPC                BIT(0)
+#define DP_GENERIC0_6_YUV_10_BPC       BIT(1)
+
+#define DP_SDP_HEADER_SIZE             8
+#define DP_VSC_SDP_BUFFER_SIZE         40

  u8 dp_utils_get_g0_value(u8 data)
  {

@@ -69,3 +79,73 @@ u8 dp_utils_calculate_parity(u32 data)

         return parity_byte;
  }
+
+int dp_utils_pack_sdp_header(struct dp_sdp_header *sdp_header, u32

*buffer, size_t buff_size)
+{
+       u32 header, parity;
+
+       if (buff_size < DP_SDP_HEADER_SIZE)
+               return -ENOSPC;
+
+       memset(buffer, 0, sizeof(buffer));
+
+       /* HEADER BYTE 0 */
+       header = sdp_header->HB0;
+       parity = dp_utils_calculate_parity(header);
+       buffer[0]   = ((header << HEADER_BYTE_0_BIT) | (parity <<
PARITY_BYTE_0_BIT));
+
+       /* HEADER BYTE 1 */
+       header = sdp_header->HB1;
+       parity = dp_utils_calculate_parity(header);
+       buffer[0]  |= ((header << HEADER_BYTE_1_BIT) | (parity <<
PARITY_BYTE_1_BIT));
+
+       /* HEADER BYTE 2 */
+       header = sdp_header->HB2;
+       parity = dp_utils_calculate_parity(header);
+       buffer[1]   = ((header << HEADER_BYTE_2_BIT) | (parity <<
PARITY_BYTE_2_BIT));
+
+       /* HEADER BYTE 3 */
+       header = sdp_header->HB3;
+       parity = dp_utils_calculate_parity(header);
+       buffer[1]  |= ((header << HEADER_BYTE_3_BIT) | (parity <<
PARITY_BYTE_3_BIT));
+
+       return 0;
+}
+
+int dp_utils_pack_vsc_sdp(struct drm_dp_vsc_sdp *vsc_sdp_data,
struct dp_sdp_header *sdp_header,
+                         u32 *buffer, size_t buff_size)
+{

No. This function should pack data into struct dp_sdp and it should go
to drivers/video/hdmi.c

What is the difference between struct drm_dp_vsc_sdp and struct dp_sdp?

I think you were referring to the fact that instead of a custom buffer,
we should use struct dp_sdp to pack elements from struct drm_dp_vsc_sdp.

If yes, I agree with this part.

Yes.

quoted

It seems like struct drm_dp_vsc_sdp is more appropriate for this.

Regarding hdmi.c, I think the packing needs to be more generic to move
it there.

I am not seeing parity bytes packing with other vendors. So there will
have to be some packing there and then some packing here.

Yes. Writing the HB + PB seems specific to Qualcomm hardware. At least
Intel and AMD seem to write header bytes without parity.

quoted

Also, like you already noticed, to make the VSC SDP packing more generic
to move to hdmi.c, it needs more work to make it more usable like
supporting all pixel formats and all colorimetry values.

We do not have that much utility yet for that.

I think you are mixing the filling of drm_dp_vsc_sdp and packing of
that struct. I suppose intel_dp_vsc_sdp_pack() can be extracted more
or less as is.
Once somebody needs to support 3D (AMD does), they can extend the function.

quoted

Thats why I wrote even in V1 that I will certainly do the migration to
dp_utils for this one but cannot commit for hdmi.c in this series.

quoted

quoted

+       u8 bpc;
+       int ret = 0;
+
+       if (buff_size < DP_VSC_SDP_BUFFER_SIZE)
+               return -ENOSPC;
+
+       ret = dp_utils_pack_sdp_header(sdp_header, buffer, buff_size);
+       if (ret) {
+               DRM_ERROR("unable to pack sdp header\n");
+               return ret;
+       }
+
+       switch (vsc_sdp_data->bpc) {
+       case 10:
+               bpc = DP_GENERIC0_6_YUV_10_BPC;
+               break;
+       case 8:
+       default:
+               bpc = DP_GENERIC0_6_YUV_8_BPC;
+               break;
+       }
+
+       /* VSC SDP payload as per table 2-117 of DP 1.4 specification */
+       buffer[6] = (vsc_sdp_data->colorimetry & 0xF) |
+              ((vsc_sdp_data->pixelformat & 0xF) << 4) |
+              (bpc << 8) |
+              ((vsc_sdp_data->dynamic_range & 0x1) << 15) |
+              ((vsc_sdp_data->content_type & 0x7) << 16);
+
+       print_hex_dump(KERN_DEBUG, "[drm-dp] VSC: ",
DUMP_PREFIX_NONE, 16, 4, buffer,
+                      sizeof(buffer), false);
+
+       return ret;
+}

diff --git a/drivers/gpu/drm/msm/dp/dp_utils.h

b/drivers/gpu/drm/msm/dp/dp_utils.h
index c062e29d07898..7fd775de553c9 100644

--- a/drivers/gpu/drm/msm/dp/dp_utils.h
+++ b/drivers/gpu/drm/msm/dp/dp_utils.h

@@ -18,5 +18,8 @@
  u8 dp_utils_get_g0_value(u8 data);
  u8 dp_utils_get_g1_value(u8 data);
  u8 dp_utils_calculate_parity(u32 data);
+int dp_utils_pack_sdp_header(struct dp_sdp_header *sdp_header, u32

*buffer, size_t buff_size);
+int dp_utils_pack_vsc_sdp(struct drm_dp_vsc_sdp *vsc_sdp_data,
struct dp_sdp_header *sdp_header,
+                         u32 *buffer, size_t buff_size);

  #endif /* _DP_UTILS_H_ */
--
2.39.2

-- 
With best wishes
Dmitry