From: Nicholas Kazlauskas <nicholas.kazlaus...@amd.com>

[Why]
To maintain compatibility with firmware older than 4.0.11.

Those firmware may have interrmittent hangs with RDCSPIPE or the PHY,
but we shouldn't regress their previous behavior.

[How]
Use the new path if firmware is development or 4.0.11 or newer. Use the
legacy path otherwise.

Fixes: b60a041393f7 ("drm/amd/display: Query DMCUB for dp alt status")

Reviewed-by: Hansen Dsouza <hansen.dso...@amd.com>
Acked-by: Rodrigo Siqueira <rodrigo.sique...@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlaus...@amd.com>
---
 .../display/dc/dcn31/dcn31_dio_link_encoder.c | 114 +++++++++++++++---
 1 file changed, 94 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_dio_link_encoder.c 
b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_dio_link_encoder.c
index 71c359f9cdd2..8b9b1a5309ba 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_dio_link_encoder.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_dio_link_encoder.c
@@ -100,6 +100,35 @@ static uint8_t phy_id_from_transmitter(enum transmitter t)
        return phy_id;
 }
 
+static bool has_query_dp_alt(struct link_encoder *enc)
+{
+       struct dc_dmub_srv *dc_dmub_srv = enc->ctx->dmub_srv;
+
+       /* Supports development firmware and firmware >= 4.0.11 */
+       return dc_dmub_srv &&
+              !(dc_dmub_srv->dmub->fw_version >= DMUB_FW_VERSION(4, 0, 0) &&
+                dc_dmub_srv->dmub->fw_version <= DMUB_FW_VERSION(4, 0, 10));
+}
+
+static bool query_dp_alt_from_dmub(struct link_encoder *enc,
+                                  union dmub_rb_cmd *cmd)
+{
+       struct dcn10_link_encoder *enc10 = TO_DCN10_LINK_ENC(enc);
+       struct dc_dmub_srv *dc_dmub_srv = enc->ctx->dmub_srv;
+
+       memset(cmd, 0, sizeof(*cmd));
+       cmd->query_dp_alt.header.type = DMUB_CMD__VBIOS;
+       cmd->query_dp_alt.header.sub_type =
+               DMUB_CMD__VBIOS_TRANSMITTER_QUERY_DP_ALT;
+       cmd->query_dp_alt.header.payload_bytes = sizeof(cmd->query_dp_alt.data);
+       cmd->query_dp_alt.data.phy_id = 
phy_id_from_transmitter(enc10->base.transmitter);
+
+       if (!dc_dmub_srv_cmd_with_reply_data(dc_dmub_srv, cmd))
+               return false;
+
+       return true;
+}
+
 void dcn31_link_encoder_set_dio_phy_mux(
        struct link_encoder *enc,
        enum encoder_type_select sel,
@@ -569,45 +598,90 @@ void dcn31_link_encoder_disable_output(
 bool dcn31_link_encoder_is_in_alt_mode(struct link_encoder *enc)
 {
        struct dcn10_link_encoder *enc10 = TO_DCN10_LINK_ENC(enc);
-       struct dc_dmub_srv *dc_dmub_srv = enc->ctx->dmub_srv;
        union dmub_rb_cmd cmd;
-       bool is_usb_c_alt_mode = false;
+       uint32_t dp_alt_mode_disable;
 
-       if (enc->features.flags.bits.DP_IS_USB_C && dc_dmub_srv) {
-               memset(&cmd, 0, sizeof(cmd));
-               cmd.query_dp_alt.header.type = DMUB_CMD__VBIOS;
-               cmd.query_dp_alt.header.sub_type = 
DMUB_CMD__VBIOS_TRANSMITTER_QUERY_DP_ALT;
-               cmd.query_dp_alt.header.payload_bytes = 
sizeof(cmd.panel_cntl.data);
-               cmd.query_dp_alt.data.phy_id = 
phy_id_from_transmitter(enc10->base.transmitter);
+       /* Only applicable to USB-C PHY. */
+       if (!enc->features.flags.bits.DP_IS_USB_C)
+               return false;
 
-               if (!dc_dmub_srv_cmd_with_reply_data(dc_dmub_srv, &cmd))
+       /*
+        * Use the new interface from DMCUB if available.
+        * Avoids hanging the RDCPSPIPE if DMCUB wasn't already running.
+        */
+       if (has_query_dp_alt(enc)) {
+               if (!query_dp_alt_from_dmub(enc, &cmd))
                        return false;
 
-               is_usb_c_alt_mode = (cmd.query_dp_alt.data.is_dp_alt_disable == 
0);
+               return (cmd.query_dp_alt.data.is_dp_alt_disable == 0);
        }
 
-       return is_usb_c_alt_mode;
+       /* Legacy path, avoid if possible. */
+       if (enc->ctx->asic_id.hw_internal_rev != YELLOW_CARP_B0) {
+               REG_GET(RDPCSTX_PHY_CNTL6, RDPCS_PHY_DPALT_DISABLE,
+                       &dp_alt_mode_disable);
+       } else {
+               /*
+                * B0 phys use a new set of registers to check whether alt mode 
is disabled.
+                * if value == 1 alt mode is disabled, otherwise it is enabled.
+                */
+               if ((enc10->base.transmitter == TRANSMITTER_UNIPHY_A) ||
+                   (enc10->base.transmitter == TRANSMITTER_UNIPHY_B) ||
+                   (enc10->base.transmitter == TRANSMITTER_UNIPHY_E)) {
+                       REG_GET(RDPCSTX_PHY_CNTL6, RDPCS_PHY_DPALT_DISABLE,
+                               &dp_alt_mode_disable);
+               } else {
+                       REG_GET(RDPCSPIPE_PHY_CNTL6, RDPCS_PHY_DPALT_DISABLE,
+                               &dp_alt_mode_disable);
+               }
+       }
+
+       return (dp_alt_mode_disable == 0);
 }
 
 void dcn31_link_encoder_get_max_link_cap(struct link_encoder *enc, struct 
dc_link_settings *link_settings)
 {
        struct dcn10_link_encoder *enc10 = TO_DCN10_LINK_ENC(enc);
-       struct dc_dmub_srv *dc_dmub_srv = enc->ctx->dmub_srv;
        union dmub_rb_cmd cmd;
+       uint32_t is_in_usb_c_dp4_mode = 0;
 
        dcn10_link_encoder_get_max_link_cap(enc, link_settings);
 
-       if (enc->features.flags.bits.DP_IS_USB_C && dc_dmub_srv) {
-               memset(&cmd, 0, sizeof(cmd));
-               cmd.query_dp_alt.header.type = DMUB_CMD__VBIOS;
-               cmd.query_dp_alt.header.sub_type = 
DMUB_CMD__VBIOS_TRANSMITTER_QUERY_DP_ALT;
-               cmd.query_dp_alt.header.payload_bytes = 
sizeof(cmd.panel_cntl.data);
-               cmd.query_dp_alt.data.phy_id = 
phy_id_from_transmitter(enc10->base.transmitter);
+       /* Take the link cap directly if not USB */
+       if (!enc->features.flags.bits.DP_IS_USB_C)
+               return;
 
-               if (!dc_dmub_srv_cmd_with_reply_data(dc_dmub_srv, &cmd))
+       /*
+        * Use the new interface from DMCUB if available.
+        * Avoids hanging the RDCPSPIPE if DMCUB wasn't already running.
+        */
+       if (has_query_dp_alt(enc)) {
+               if (!query_dp_alt_from_dmub(enc, &cmd))
                        return;
 
-               if (cmd.query_dp_alt.data.is_usb && 
cmd.query_dp_alt.data.is_dp4 == 0)
+               if (cmd.query_dp_alt.data.is_usb &&
+                   cmd.query_dp_alt.data.is_dp4 == 0)
                        link_settings->lane_count = MIN(LANE_COUNT_TWO, 
link_settings->lane_count);
+
+               return;
        }
+
+       /* Legacy path, avoid if possible. */
+       if (enc->ctx->asic_id.hw_internal_rev != YELLOW_CARP_B0) {
+               REG_GET(RDPCSTX_PHY_CNTL6, RDPCS_PHY_DPALT_DP4,
+                       &is_in_usb_c_dp4_mode);
+       } else {
+               if ((enc10->base.transmitter == TRANSMITTER_UNIPHY_A) ||
+                   (enc10->base.transmitter == TRANSMITTER_UNIPHY_B) ||
+                   (enc10->base.transmitter == TRANSMITTER_UNIPHY_E)) {
+                       REG_GET(RDPCSTX_PHY_CNTL6, RDPCS_PHY_DPALT_DP4,
+                               &is_in_usb_c_dp4_mode);
+               } else {
+                       REG_GET(RDPCSPIPE_PHY_CNTL6, RDPCS_PHY_DPALT_DP4,
+                               &is_in_usb_c_dp4_mode);
+               }
+       }
+
+       if (!is_in_usb_c_dp4_mode)
+               link_settings->lane_count = MIN(LANE_COUNT_TWO, 
link_settings->lane_count);
 }
-- 
2.25.1

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