Re: [PATCH v3 13/19] drm/msm/dp: add VSC SDP support for YUV420 over DP

[Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>]

On 2/14/2024 11:39 AM, Dmitry Baryshkov wrote:
> On Wed, 14 Feb 2024 at 20:04, Paloma Arellano <quic_parellan@xxxxxxxxxxx> wrote:
> > 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 v3:
> >          - Create a new struct, msm_dp_sdp_with_parity, which holds the
> >            packing information for VSC SDP
> >          - Use drm_dp_vsc_sdp_pack() to pack the data into the new
> >            msm_dp_sdp_with_parity struct instead of specifically packing
> >            for YUV420 format
> >          - Modify dp_catalog_panel_send_vsc_sdp() to send the VSC SDP
> >            data using the new msm_dp_sdp_with_parity struct
> >
> > 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 <quic_parellan@xxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/msm/dp/dp_catalog.c | 113 ++++++++++++++++++++++++++++
> >   drivers/gpu/drm/msm/dp/dp_catalog.h |   7 ++
> >   drivers/gpu/drm/msm/dp/dp_ctrl.c    |   4 +
> >   drivers/gpu/drm/msm/dp/dp_panel.c   |  55 ++++++++++++++
> >   drivers/gpu/drm/msm/dp/dp_reg.h     |   3 +
> >   drivers/gpu/drm/msm/dp/dp_utils.c   |  48 ++++++++++++
> >   drivers/gpu/drm/msm/dp/dp_utils.h   |  18 +++++
> >   7 files changed, 248 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c b/drivers/gpu/drm/msm/dp/dp_catalog.c
> > index 5d84c089e520a..61d5317efe683 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_catalog.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_catalog.c
> > @@ -901,6 +901,119 @@ 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,
> > +                                         struct msm_dp_sdp_with_parity *msm_dp_sdp)
> > +{
> > +       struct dp_catalog_private *catalog;
> > +       u32 val;
> > +
> > +       if (!dp_catalog) {
> > +               DRM_ERROR("invalid input\n");
> > +               return;
> > +       }
> > +
> > +       catalog = container_of(dp_catalog, struct dp_catalog_private, dp_catalog);
> > +
> > +       val = ((msm_dp_sdp->vsc_sdp.sdp_header.HB0) << HEADER_BYTE_0_BIT |
> > +              (msm_dp_sdp->pb.PB0 << PARITY_BYTE_0_BIT) |
> > +              (msm_dp_sdp->vsc_sdp.sdp_header.HB1) << HEADER_BYTE_1_BIT |
> > +              (msm_dp_sdp->pb.PB1 << PARITY_BYTE_1_BIT));
> > +       dp_write_link(catalog, MMSS_DP_GENERIC0_0, val);
> > +
> > +       val = ((msm_dp_sdp->vsc_sdp.sdp_header.HB2) << HEADER_BYTE_2_BIT |
> > +              (msm_dp_sdp->pb.PB2 << PARITY_BYTE_2_BIT) |
> > +              (msm_dp_sdp->vsc_sdp.sdp_header.HB3) << HEADER_BYTE_3_BIT |
> > +              (msm_dp_sdp->pb.PB3 << PARITY_BYTE_3_BIT));
> > +       dp_write_link(catalog, MMSS_DP_GENERIC0_1, val);
>
> I still think that this is not the way to do it. Could you please
> extract the function that takes struct dp_sdp_header, calculates
> padding and writes resulting data to the hardware? This way we can
> reuse it later for all the dp_audio stuff.

hmmm ... dp_utils_pack_sdp_header() does that you are asking for right?

OR are you asking for another function like:

1) rename dp_utils_pack_sdp_header() to dp_utils_calc_sdp_parity()
2) dp_utils_pack_sdp() takes two u32 to pack the header and parity 
together and we move the << HEADER_BYTE_xx | part to it

dp_catalog_panel_send_vsc_sdp() just uses these two u32 to write the 
headers.


> > +
> > +       val = ((msm_dp_sdp->vsc_sdp.db[16]) | (msm_dp_sdp->vsc_sdp.db[17] << 8) |
> > +              (msm_dp_sdp->vsc_sdp.db[18] << 16));
> > +       dp_write_link(catalog, MMSS_DP_GENERIC0_6, val);
>
> Shouldn't we write full dp_sdp data, including all zeroes? Here you
> assume that there is no other data in dp_sdp and also that nobody
> wrote anything senseless to those registers.

As per documentation, it says db[0] to db[15] are reserved so I thought 
its better not to touch/use them and start writing for 16 onwards.

1592  * VSC SDP Payload for Pixel Encoding/Colorimetry Format
1593  * db[0] - db[15]: Reserved
1594  * db[16]: Pixel Encoding and Colorimetry Formats
1595  * db[17]: Dynamic Range and Component Bit Depth
1596  * db[18]: Content Type
1597  * db[19] - db[31]: Reserved
1598  */

> > +}
> > +
> > +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,
> > +                                    struct msm_dp_sdp_with_parity *msm_dp_sdp)
> > +{
> > +       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, msm_dp_sdp);
> > +
> > +       /* 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..4bf08c27a9bf3 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_catalog.h
> > +++ b/drivers/gpu/drm/msm/dp/dp_catalog.h
> > @@ -9,6 +9,7 @@
> >   #include <drm/drm_modes.h>
> >
> >   #include "dp_parser.h"
> > +#include "dp_utils.h"
> >   #include "disp/msm_disp_snapshot.h"
> >
> >   /* interrupts */
> > @@ -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 +128,9 @@ 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,
> > +                                    struct msm_dp_sdp_with_parity *msm_dp_sdp);
> > +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..18420a7ba4ab3 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 +282,56 @@ 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 drm_dp_vsc_sdp vsc_sdp_data;
> > +       struct msm_dp_sdp_with_parity msm_dp_sdp;
> > +       ssize_t len;
> > +       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;
> > +
> > +       memset(&vsc_sdp_data, 0, sizeof(vsc_sdp_data));
> > +
> > +       /* VSC SDP header as per table 2-118 of DP 1.4 specification */
> > +       vsc_sdp_data.sdp_type = DP_SDP_VSC;
> > +       vsc_sdp_data.revision = 0x05;
> > +       vsc_sdp_data.length = 0x13;
> > +
> > +       /* VSC SDP Payload for DB16 */
> > +       vsc_sdp_data.pixelformat = DP_PIXELFORMAT_YUV420;
> > +       vsc_sdp_data.colorimetry = DP_COLORIMETRY_DEFAULT;
> > +
> > +       /* VSC SDP Payload for DB17 */
> > +       vsc_sdp_data.bpc = dp_mode->bpp / 3;
> > +       vsc_sdp_data.dynamic_range = DP_DYNAMIC_RANGE_CTA;
> > +
> > +       /* VSC SDP Payload for DB18 */
> > +       vsc_sdp_data.content_type = DP_CONTENT_TYPE_GRAPHICS;
> > +
> > +       // rc = dp_utils_pack_vsc_sdp(&vsc_sdp_data, &sdp_header, gen_buffer, buff_size);
> > +       len = dp_utils_pack_vsc_sdp(&vsc_sdp_data, &msm_dp_sdp);
> > +       if (len < 0) {
> > +               DRM_ERROR("unable to pack vsc sdp\n");
> > +               return len;
> > +       }
> > +
> > +       dp_catalog_panel_enable_vsc_sdp(catalog, &msm_dp_sdp);
> > +
> > +       return rc;
> > +}
> > +
> >   void dp_panel_dump_regs(struct dp_panel *dp_panel)
> >   {
> >          struct dp_catalog *catalog;
> > @@ -344,6 +395,10 @@ 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 3a44fe738c004..81601f3c414fc 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_utils.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_utils.c
> > @@ -4,6 +4,7 @@
> >    */
> >
> >   #include <linux/types.h>
> > +#include <drm/drm_print.h>
> >
> >   #include "dp_utils.h"
> >
> > @@ -71,3 +72,50 @@ u8 dp_utils_calculate_parity(u32 data)
> >
> >          return parity_byte;
> >   }
> > +
> > +ssize_t dp_utils_pack_sdp_header(struct dp_sdp_header *sdp_header, struct msm_dp_vsc_sdp_parity *pb,
> > +                                size_t size)
> > +{
> > +       u8 header;
> > +
> > +       size_t length = sizeof(struct msm_dp_vsc_sdp_parity);
> > +
> > +       if (size < length)
> > +               return -ENOSPC;
> > +
> > +       memset(pb, 0, size);
> > +
> > +       header = sdp_header->HB0;
> > +       pb->PB0 = dp_utils_calculate_parity(header);
> > +
> > +       header = sdp_header->HB1;
> > +       pb->PB1 = dp_utils_calculate_parity(header);
> > +
> > +       header = sdp_header->HB2;
> > +       pb->PB2 = dp_utils_calculate_parity(header);
> > +
> > +       header = sdp_header->HB3;
> > +       pb->PB3 = dp_utils_calculate_parity(header);
> > +
> > +       return length;
> > +}
> > +
> > +ssize_t dp_utils_pack_vsc_sdp(struct drm_dp_vsc_sdp *vsc, struct msm_dp_sdp_with_parity *msm_dp_sdp)
> > +{
> > +       ssize_t len;
> > +
> > +       len = drm_dp_vsc_sdp_pack(vsc, &msm_dp_sdp->vsc_sdp, sizeof(msm_dp_sdp->vsc_sdp));
> > +       if (len < 0) {
> > +               DRM_ERROR("unable to pack vsc sdp\n");
> > +               return len;
> > +       }
> > +
> > +       len = dp_utils_pack_sdp_header(&msm_dp_sdp->vsc_sdp.sdp_header, &msm_dp_sdp->pb,
> > +                                      sizeof(msm_dp_sdp->pb));
> > +       if (len < 0) {
> > +               DRM_ERROR("unable to pack sdp header\n");
> > +               return len;
> > +       }
> > +
> > +       return len;
> > +}
> > diff --git a/drivers/gpu/drm/msm/dp/dp_utils.h b/drivers/gpu/drm/msm/dp/dp_utils.h
> > index 5a505cbf3432b..6946bc51cae97 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_utils.h
> > +++ b/drivers/gpu/drm/msm/dp/dp_utils.h
> > @@ -6,6 +6,8 @@
> >   #ifndef _DP_UTILS_H_
> >   #define _DP_UTILS_H_
> >
> > +#include <drm/display/drm_dp_helper.h>
> > +
> >   #define HEADER_BYTE_0_BIT       0
> >   #define PARITY_BYTE_0_BIT       8
> >   #define HEADER_BYTE_1_BIT      16
> > @@ -15,8 +17,24 @@
> >   #define HEADER_BYTE_3_BIT      16
> >   #define PARITY_BYTE_3_BIT      24
> >
> > +struct msm_dp_vsc_sdp_parity {
> > +       u8 PB0;
> > +       u8 PB1;
> > +       u8 PB2;
> > +       u8 PB3;
> > +} __packed;
> > +
> > +struct msm_dp_sdp_with_parity {
> > +       struct dp_sdp vsc_sdp;
> > +       struct msm_dp_vsc_sdp_parity pb;
> > +};
> > +
> >   u8 dp_utils_get_g0_value(u8 data);
> >   u8 dp_utils_get_g1_value(u8 data);
> >   u8 dp_utils_calculate_parity(u32 data);
> > +ssize_t dp_utils_pack_sdp_header(struct dp_sdp_header *sdp_header, struct msm_dp_vsc_sdp_parity *pb,
> > +                                size_t size);
> > +ssize_t dp_utils_pack_vsc_sdp(struct drm_dp_vsc_sdp *vsc,
> > +                             struct msm_dp_sdp_with_parity *msm_dp_sdp);
> >
> >   #endif /* _DP_UTILS_H_ */
> > --
> > 2.39.2