lib/igt_eld: consolidate ELD parsing

Make the ELD enumeration more robust, and implement proper parsing for ELD
fields. This will become useful when other ELD fields (formats, sample rates,
sample sizes) will be parsed and checked.

Signed-off-by: Simon Ser <simon.ser@intel.com>
Reviewed-by: Martin Peres <martin.peres@linux.intel.com>

1 files changed, 82 insertions, 36 deletions

diff --git a/lib/igt_eld.c b/lib/igt_eld.c
index 8e0dcc30..2f98b51e 100644
--- a/lib/igt_eld.c
+++ b/lib/igt_eld.c
@@ -30,8 +30,12 @@
 #include <stdio.h>
 #include <string.h>
 
+#include "igt_core.h"
 #include "igt_eld.h"
 
+#define ELD_PREFIX "eld#"
+#define ELD_DELIM " \t"
+
 /**
  * EDID-Like Data (ELD) is metadata parsed and exposed by ALSA for HDMI and
  * DisplayPort connectors supporting audio. This includes the monitor name and
@@ -39,39 +43,73 @@
  * on).
  */
 
-/** eld_entry_is_igt: checks whether an ELD entry is mapped to the IGT EDID */
-static bool eld_entry_is_igt(const char *path)
+/** eld_parse_entry: parse an ELD entry
+ *
+ * Here is an example of an ELD entry:
+ *
+ *     $ cat /proc/asound/card0/eld#0.2
+ *     monitor_present         1
+ *     eld_valid               1
+ *     monitor_name            U2879G6
+ *     connection_type         DisplayPort
+ *     eld_version             [0x2] CEA-861D or below
+ *     edid_version            [0x3] CEA-861-B, C or D
+ *     manufacture_id          0xe305
+ *     product_id              0x2879
+ *     port_id                 0x800
+ *     support_hdcp            0
+ *     support_ai              0
+ *     audio_sync_delay        0
+ *     speakers                [0x1] FL/FR
+ *     sad_count               1
+ *     sad0_coding_type        [0x1] LPCM
+ *     sad0_channels           2
+ *     sad0_rates              [0xe0] 32000 44100 48000
+ *     sad0_bits               [0xe0000] 16 20 24
+ */
+static bool eld_parse_entry(const char *path, struct eld_entry *eld)
 {
-	FILE *in;
+	FILE *f;
 	char buf[1024];
-	uint8_t eld_valid = 0;
-	uint8_t mon_valid = 0;
-
-	in = fopen(path, "r");
-	if (!in)
-		return false;
+	char *key, *value;
+	size_t len;
+	bool monitor_present;
 
-	memset(buf, 0, 1024);
+	memset(eld, 0, sizeof(*eld));
 
-	while ((fgets(buf, 1024, in)) != NULL) {
-		char *line = buf;
+	f = fopen(path, "r");
+	if (!f) {
+		igt_debug("Failed to open ELD file: %s\n", path);
+		return false;
+	}
 
-		if (!strncasecmp(line, "eld_valid", 9) &&
-				strstr(line, "1")) {
-			eld_valid++;
-		}
+	while ((fgets(buf, sizeof(buf), f)) != NULL) {
+		len = strlen(buf);
+		if (buf[len - 1] == '\n')
+			buf[len - 1] = '\0';
+
+		key = strtok(buf, ELD_DELIM);
+		value = strtok(NULL, "");
+		/* Skip whitespace at the beginning */
+		value += strspn(value, ELD_DELIM);
+
+		if (strcmp(key, "monitor_present") == 0)
+			monitor_present = strcmp(value, "1") == 0;
+		else if (strcmp(key, "eld_valid") == 0)
+			eld->valid = strcmp(value, "1") == 0;
+		else if (strcmp(key, "monitor_name") == 0)
+			snprintf(eld->monitor_name, sizeof(eld->monitor_name),
+				 "%s", value);
+	}
 
-		if (!strncasecmp(line, "monitor_name", 12) &&
-				strstr(line, "IGT")) {
-			mon_valid++;
-		}
+	if (ferror(f) != 0) {
+		igt_debug("Failed to read ELD file: %d\n", ferror(f));
+		return false;
 	}
 
-	fclose(in);
-	if (mon_valid && eld_valid)
-		return true;
+	fclose(f);
 
-	return false;
+	return monitor_present;
 }
 
 /** eld_has_igt: check whether ALSA has detected the audio-capable IGT EDID by
@@ -79,27 +117,35 @@ static bool eld_entry_is_igt(const char *path)
 bool eld_has_igt(void)
 {
 	DIR *dir;
-	struct dirent *snd_hda;
+	struct dirent *dirent;
 	int i;
+	char card[64];
+	char path[PATH_MAX];
+	struct eld_entry eld;
 
 	for (i = 0; i < 8; i++) {
-		char cards[128];
-
-		snprintf(cards, sizeof(cards), "/proc/asound/card%d", i);
-		dir = opendir(cards);
+		snprintf(card, sizeof(card), "/proc/asound/card%d", i);
+		dir = opendir(card);
 		if (!dir)
 			continue;
 
-		while ((snd_hda = readdir(dir))) {
-			char fpath[PATH_MAX];
+		while ((dirent = readdir(dir))) {
+			if (strncmp(dirent->d_name, ELD_PREFIX,
+				    strlen(ELD_PREFIX)) != 0)
+				continue;
 
-			if (*snd_hda->d_name == '.' ||
-			    strstr(snd_hda->d_name, "eld") == 0)
+			snprintf(path, sizeof(path), "%s/%s", card,
+				 dirent->d_name);
+			if (!eld_parse_entry(path, &eld)) {
 				continue;
+			}
+
+			if (!eld.valid) {
+				igt_debug("Skipping invalid ELD: %s\n", path);
+				continue;
+			}
 
-			snprintf(fpath, sizeof(fpath), "%s/%s", cards,
-				 snd_hda->d_name);
-			if (eld_entry_is_igt(fpath)) {
+			if (strcmp(eld.monitor_name, "IGT") == 0) {
 				closedir(dir);
 				return true;
 			}