drm/dp: Add Adaptive Sync SDP logging

Add structure representing Adaptive Sync Secondary Data Packet (AS SDP).
Also, add Adaptive Sync SDP logging in drm_dp_helper.c to facilitate
debugging.

--v2:
- Update logging. [Jani, Ankit]
- Use 'as_sdp' instead of 'async' [Ankit]
- Correct define placeholders to where they are actually used. [Jani]
- Update members in 'as_sdp' structure to make it uniform. [Jani]

--v3:
- Added changes to dri-devel mailing list. No code changes.

--v4:
- Instead of directly using operation mode, use an enum to accommodate
all operation modes (Ankit).

--v5:
Nit-pick changes to commit message.

--v6:
- Add correct place holder and name change for AS_SDP_OP_MODE.
- Separate i915 changes from drm changes.
- Remove extra lines.

--v7:
- Add drm/dp in subject line (Ankit)
Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240322031157.3823909-3-mitulkumar.ajitkumar.golani@intel.com

drivers/gpu/drm/display/drm_dp_helper.c

@@ -2948,6 +2948,18 @@ void drm_dp_vsc_sdp_log(struct drm_printer *p, const struct drm_dp_vsc_sdp *vsc)
 }
 EXPORT_SYMBOL(drm_dp_vsc_sdp_log);
 
+void drm_dp_as_sdp_log(struct drm_printer *p, const struct drm_dp_as_sdp *as_sdp)
+{
+	drm_printf(p, "DP SDP: AS_SDP, revision %u, length %u\n",
+		   as_sdp->revision, as_sdp->length);
+	drm_printf(p, "    vtotal: %d\n", as_sdp->vtotal);
+	drm_printf(p, "    target_rr: %d\n", as_sdp->target_rr);
+	drm_printf(p, "    duration_incr_ms: %d\n", as_sdp->duration_incr_ms);
+	drm_printf(p, "    duration_decr_ms: %d\n", as_sdp->duration_decr_ms);
+	drm_printf(p, "    operation_mode: %d\n", as_sdp->mode);
+}
+EXPORT_SYMBOL(drm_dp_as_sdp_log);
+
 /**
  * drm_dp_as_sdp_supported() - check if adaptive sync sdp is supported
  * @aux: DisplayPort AUX channel

include/drm/display/drm_dp.h

@@ -1150,6 +1150,8 @@
 
 #define DP_DPRX_FEATURE_ENUMERATION_LIST_CONT_1         0x2214 /* 2.0 E11 */
 # define DP_ADAPTIVE_SYNC_SDP_SUPPORTED    (1 << 0)
+# define DP_ADAPTIVE_SYNC_SDP_OPERATION_MODE		GENMASK(1, 0)
+# define DP_ADAPTIVE_SYNC_SDP_LENGTH				GENMASK(5, 0)
 # define DP_AS_SDP_FIRST_HALF_LINE_OR_3840_PIXEL_CYCLE_WINDOW_NOT_SUPPORTED (1 << 1)
 # define DP_VSC_EXT_SDP_FRAMEWORK_VERSION_1_SUPPORTED  (1 << 4)
 
@@ -1639,10 +1641,12 @@ enum drm_dp_phy {
 #define DP_SDP_AUDIO_COPYMANAGEMENT	0x05 /* DP 1.2 */
 #define DP_SDP_ISRC			0x06 /* DP 1.2 */
 #define DP_SDP_VSC			0x07 /* DP 1.2 */
+#define DP_SDP_ADAPTIVE_SYNC		0x22 /* DP 1.4 */
 #define DP_SDP_CAMERA_GENERIC(i)	(0x08 + (i)) /* 0-7, DP 1.3 */
 #define DP_SDP_PPS			0x10 /* DP 1.4 */
 #define DP_SDP_VSC_EXT_VESA		0x20 /* DP 1.4 */
 #define DP_SDP_VSC_EXT_CEA		0x21 /* DP 1.4 */
+
 /* 0x80+ CEA-861 infoframe types */
 
 #define DP_SDP_AUDIO_INFOFRAME_HB2	0x1b
@@ -1798,4 +1802,11 @@ enum dp_content_type {
 	DP_CONTENT_TYPE_GAME = 0x04,
 };
 
+enum operation_mode {
+	DP_AS_SDP_AVT_DYNAMIC_VTOTAL = 0x00,
+	DP_AS_SDP_AVT_FIXED_VTOTAL = 0x01,
+	DP_AS_SDP_FAVT_TRR_NOT_REACHED = 0x02,
+	DP_AS_SDP_FAVT_TRR_REACHED = 0x03
+};
+
 #endif /* _DRM_DP_H_ */

include/drm/display/drm_dp_helper.h

@@ -98,6 +98,35 @@ struct drm_dp_vsc_sdp {
 	enum dp_content_type content_type;
 };
 
+/**
+ * struct drm_dp_as_sdp - drm DP Adaptive Sync SDP
+ *
+ * This structure represents a DP AS SDP of drm
+ * It is based on DP 2.1 spec [Table 2-126:  Adaptive-Sync SDP Header Bytes] and
+ * [Table 2-127: Adaptive-Sync SDP Payload for DB0 through DB8]
+ *
+ * @sdp_type: Secondary-data packet type
+ * @revision: Revision Number
+ * @length: Number of valid data bytes
+ * @vtotal: Minimum Vertical Vtotal
+ * @target_rr: Target Refresh
+ * @duration_incr_ms: Successive frame duration increase
+ * @duration_decr_ms: Successive frame duration decrease
+ * @operation_mode: Adaptive Sync Operation Mode
+ */
+struct drm_dp_as_sdp {
+	unsigned char sdp_type;
+	unsigned char revision;
+	unsigned char length;
+	int vtotal;
+	int target_rr;
+	int duration_incr_ms;
+	int duration_decr_ms;
+	enum operation_mode mode;
+};
+
+void drm_dp_as_sdp_log(struct drm_printer *p,
+		       const struct drm_dp_as_sdp *as_sdp);
 void drm_dp_vsc_sdp_log(struct drm_printer *p, const struct drm_dp_vsc_sdp *vsc);
 
 bool drm_dp_vsc_sdp_supported(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE]);