3 files changed, 189 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 7425e5c9bd75..fe39c3570538 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1319,6 +1319,7 @@ add_detailed_modes(struct drm_connector *connector, struct edid *edid,
 #define HDMI_IDENTIFIER 0x000C03
 #define AUDIO_BLOCK     0x01
 #define VENDOR_BLOCK    0x03
+#define SPEAKER_BLOCK   0x04
 #define EDID_BASIC_AUDIO        (1 << 6)
 
 /**
@@ -1347,6 +1348,176 @@ u8 *drm_find_cea_extension(struct edid *edid)
 }
 EXPORT_SYMBOL(drm_find_cea_extension);
 
+static void
+parse_hdmi_vsdb(struct drm_connector *connector, uint8_t *db)
+{
+        connector->eld[5] |= (db[6] >> 7) << 1;  /* Supports_AI */
+
+        connector->dvi_dual = db[6] & 1;
+        connector->max_tmds_clock = db[7] * 5;
+
+        connector->latency_present[0] = db[8] >> 7;
+        connector->latency_present[1] = (db[8] >> 6) & 1;
+        connector->video_latency[0] = db[9];
+        connector->audio_latency[0] = db[10];
+        connector->video_latency[1] = db[11];
+        connector->audio_latency[1] = db[12];
+
+        DRM_LOG_KMS("HDMI: DVI dual %d, "
+                    "max TMDS clock %d, "
+                    "latency present %d %d, "
+                    "video latency %d %d, "
+                    "audio latency %d %d\n",
+                    connector->dvi_dual,
+                    connector->max_tmds_clock,
+              (int) connector->latency_present[0],
+              (int) connector->latency_present[1],
+                    connector->video_latency[0],
+                    connector->video_latency[1],
+                    connector->audio_latency[0],
+                    connector->audio_latency[1]);
+}
+
+static void
+monitor_name(struct detailed_timing *t, void *data)
+{
+        if (t->data.other_data.type == EDID_DETAIL_MONITOR_NAME)
+                *(u8 **)data = t->data.other_data.data.str.str;
+}
+
+/**
+ * drm_edid_to_eld - build ELD from EDID
+ * @connector: connector corresponding to the HDMI/DP sink
+ * @edid: EDID to parse
+ *
+ * Fill the ELD (EDID-Like Data) buffer for passing to the audio driver.
+ * Some ELD fields are left to the graphics driver caller:
+ * - Conn_Type
+ * - HDCP
+ * - Port_ID
+ */
+void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid)
+{
+        uint8_t *eld = connector->eld;
+        u8 *cea;
+        u8 *name;
+        u8 *db;
+        int sad_count = 0;
+        int mnl;
+        int dbl;
+
+        memset(eld, 0, sizeof(connector->eld));
+
+        cea = drm_find_cea_extension(edid);
+        if (!cea) {
+                DRM_DEBUG_KMS("ELD: no CEA Extension found\n");
+                return;
+        }
+
+        name = NULL;
+        drm_for_each_detailed_block((u8 *)edid, monitor_name, &name);
+        for (mnl = 0; name && mnl < 13; mnl++) {
+                if (name[mnl] == 0x0a)
+                        break;
+                eld[20 + mnl] = name[mnl];
+        }
+        eld[4] = (cea[1] << 5) | mnl;
+        DRM_DEBUG_KMS("ELD monitor %s\n", eld + 20);
+
+        eld[0] = 2 << 3;                /* ELD version: 2 */
+
+        eld[16] = edid->mfg_id[0];
+        eld[17] = edid->mfg_id[1];
+        eld[18] = edid->prod_code[0];
+        eld[19] = edid->prod_code[1];
+
+        for (db = cea + 4; db < cea + cea[2]; db += dbl + 1) {
+                dbl = db[0] & 0x1f;
+
+                switch ((db[0] & 0xe0) >> 5) {
+                case AUDIO_BLOCK:       /* Audio Data Block, contains SADs */
+                        sad_count = dbl / 3;
+                        memcpy(eld + 20 + mnl, &db[1], dbl);
+                        break;
+                case SPEAKER_BLOCK:     /* Speaker Allocation Data Block */
+                        eld[7] = db[1];
+                        break;
+                case VENDOR_BLOCK:
+                        /* HDMI Vendor-Specific Data Block */
+                        if (db[1] == 0x03 && db[2] == 0x0c && db[3] == 0)
+                                parse_hdmi_vsdb(connector, db);
+                        break;
+                default:
+                        break;
+                }
+        }
+        eld[5] |= sad_count << 4;
+        eld[2] = (20 + mnl + sad_count * 3 + 3) / 4;
+
+        DRM_DEBUG_KMS("ELD size %d, SAD count %d\n", (int)eld[2], sad_count);
+}
+EXPORT_SYMBOL(drm_edid_to_eld);
+
+/**
+ * drm_av_sync_delay - HDMI/DP sink audio-video sync delay in millisecond
+ * @connector: connector associated with the HDMI/DP sink
+ * @mode: the display mode
+ */
+int drm_av_sync_delay(struct drm_connector *connector,
+                      struct drm_display_mode *mode)
+{
+        int i = !!(mode->flags & DRM_MODE_FLAG_INTERLACE);
+        int a, v;
+
+        if (!connector->latency_present[0])
+                return 0;
+        if (!connector->latency_present[1])
+                i = 0;
+
+        a = connector->audio_latency[i];
+        v = connector->video_latency[i];
+
+        /*
+         * HDMI/DP sink doesn't support audio or video?
+         */
+        if (a == 255 || v == 255)
+                return 0;
+
+        /*
+         * Convert raw EDID values to millisecond.
+         * Treat unknown latency as 0ms.
+         */
+        if (a)
+                a = min(2 * (a - 1), 500);
+        if (v)
+                v = min(2 * (v - 1), 500);
+
+        return max(v - a, 0);
+}
+EXPORT_SYMBOL(drm_av_sync_delay);
+
+/**
+ * drm_select_eld - select one ELD from multiple HDMI/DP sinks
+ * @encoder: the encoder just changed display mode
+ * @mode: the adjusted display mode
+ *
+ * It's possible for one encoder to be associated with multiple HDMI/DP sinks.
+ * The policy is now hard coded to simply use the first HDMI/DP sink's ELD.
+ */
+struct drm_connector *drm_select_eld(struct drm_encoder *encoder,
+                                     struct drm_display_mode *mode)
+{
+        struct drm_connector *connector;
+        struct drm_device *dev = encoder->dev;
+
+        list_for_each_entry(connector, &dev->mode_config.connector_list, head)
+                if (connector->encoder == encoder && connector->eld[0])
+                        return connector;
+
+        return NULL;
+}
+EXPORT_SYMBOL(drm_select_eld);
+
 /**
  * drm_detect_hdmi_monitor - detect whether monitor is hdmi.
  * @edid: monitor EDID information
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 44335e57eaaa..802079809282 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -466,6 +466,8 @@ enum drm_connector_force {
 /* DACs should rarely do this without a lot of testing */
 #define DRM_CONNECTOR_POLL_DISCONNECT (1 << 2)
 
+#define MAX_ELD_BYTES   128
+
 /**
  * drm_connector - central DRM connector control structure
  * @crtc: CRTC this connector is currently connected to, NULL if none
@@ -523,6 +525,13 @@ struct drm_connector {
         uint32_t force_encoder_id;
         struct drm_encoder *encoder; /* currently active encoder */
 
+        /* EDID bits */
+        uint8_t eld[MAX_ELD_BYTES];
+        bool dvi_dual;
+        int max_tmds_clock;     /* in MHz */
+        bool latency_present[2];
+        int video_latency[2];   /* [0]: progressive, [1]: interlaced */
+        int audio_latency[2];
         int null_edid_counter; /* needed to workaround some HW bugs where we get all 0s */
 };
 
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index eacb415b309a..74ce91684629 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -230,4 +230,13 @@ struct edid {
 
 #define EDID_PRODUCT_ID(e) ((e)->prod_code[0] | ((e)->prod_code[1] << 8))
 
+struct drm_encoder;
+struct drm_connector;
+struct drm_display_mode;
+void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid);
+int drm_av_sync_delay(struct drm_connector *connector,
+                      struct drm_display_mode *mode);
+struct drm_connector *drm_select_eld(struct drm_encoder *encoder,
+                                     struct drm_display_mode *mode);
+
 #endif /* __DRM_EDID_H__ */