ALSA: hda - support writing to the ELD proc file

Allow users to fix quicks of ELD ROMs by writing new values to the ELD proc
interface. The format is one or more lines of "name hex_value".

Users can add/remove/modify up to 32 SAD(Short Audio Descriptor) entries.
Signed-off-by: NWu Fengguang <wfg@linux.intel.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_eld.c

@@ -500,6 +500,59 @@ static void hdmi_print_eld_info(struct snd_info_entry *entry,
 		hdmi_print_sad_info(i, e->sad + i, buffer);
 }
 
+static void hdmi_write_eld_item(struct snd_info_entry *entry,
+				struct snd_info_buffer *buffer)
+{
+	struct hdmi_eld *e = entry->private_data;
+	char line[64];
+	char name[64];
+	char *sname;
+	long long val;
+	int n;
+
+	while (!snd_info_get_line(buffer, line, sizeof(line))) {
+		if (sscanf(line, "%s %llx", name, &val) != 2)
+			continue;
+		if (!strcmp(name, "connection_type"))
+			e->conn_type = val;
+		else if (!strcmp(name, "port_id"))
+			e->port_id = val;
+		else if (!strcmp(name, "support_hdcp"))
+			e->support_hdcp = val;
+		else if (!strcmp(name, "support_ai"))
+			e->support_ai = val;
+		else if (!strcmp(name, "audio_sync_delay"))
+			e->aud_synch_delay = val;
+		else if (!strcmp(name, "speakers"))
+			e->spk_alloc = val;
+		else if (!strcmp(name, "sad_count"))
+			e->sad_count = val;
+		else if (!strncmp(name, "sad", 3)) {
+			sname = name + 4;
+			n = name[3] - '0';
+			if (name[4] >= '0' && name[4] <= '9') {
+				sname++;
+				n = 10 * n + name[4] - '0';
+			}
+			if (n < 0 || n > 31) /* double the CEA limit */
+				continue;
+			if (!strcmp(sname, "_coding_type"))
+				e->sad[n].format = val;
+			else if (!strcmp(sname, "_channels"))
+				e->sad[n].channels = val;
+			else if (!strcmp(sname, "_rates"))
+				e->sad[n].rates = val;
+			else if (!strcmp(sname, "_bits"))
+				e->sad[n].sample_bits = val;
+			else if (!strcmp(sname, "_max_bitrate"))
+				e->sad[n].max_bitrate = val;
+			if (n >= e->sad_count)
+				e->sad_count = n + 1;
+		}
+	}
+}
+
+
 int snd_hda_eld_proc_new(struct hda_codec *codec, struct hdmi_eld *eld)
 {
 	char name[32];
@@ -512,6 +565,9 @@ int snd_hda_eld_proc_new(struct hda_codec *codec, struct hdmi_eld *eld)
 		return err;
 
 	snd_info_set_text_ops(entry, eld, hdmi_print_eld_info);
+	entry->c.text.write = hdmi_write_eld_item;
+	entry->mode |= S_IWUSR;
+
 	return 0;
 }