ALSA: firewire-tascam: change device probing processing

Currently, this driver picks up model name with be32_to_cpu() macro
to align characters. This is wrong operation because the result is
different depending on CPU endiannness.

Additionally, vendor released several versions of firmware for this
series. It's not better to assign model-dependent information to
device entry according to the version field.

This commit fixes these bugs. The name of model is picked up correctly
and used to identify model-dependent information.

Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Fixes: c0949b278515 ('ALSA: firewire-tascam: add skeleton for TASCAM FireWire series')
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/tascam/tascam.c

@@ -23,16 +23,6 @@ static struct snd_tscm_spec model_specs[] = {
 		.midi_playback_ports = 4,
 		.is_controller = true,
 	},
-	{
-		.name = "FW-1804",
-		.has_adat = true,
-		.has_spdif = true,
-		.pcm_capture_analog_channels = 8,
-		.pcm_playback_analog_channels = 2,
-		.midi_capture_ports = 2,
-		.midi_playback_ports = 4,
-		.is_controller = false,
-	},
 	{
 		.name = "FW-1082",
 		.has_adat = false,
@@ -43,34 +33,46 @@ static struct snd_tscm_spec model_specs[] = {
 		.midi_playback_ports = 2,
 		.is_controller = true,
 	},
+	/* FW-1804 may be supported. */
 };
 
-static int check_name(struct snd_tscm *tscm)
+static int identify_model(struct snd_tscm *tscm)
 {
 	struct fw_device *fw_dev = fw_parent_device(tscm->unit);
-	char vendor[8];
+	const u32 *config_rom = fw_dev->config_rom;
 	char model[8];
-	__u32 data;
-
-	/* Retrieve model name. */
-	data = be32_to_cpu(fw_dev->config_rom[28]);
-	memcpy(model, &data, 4);
-	data = be32_to_cpu(fw_dev->config_rom[29]);
-	memcpy(model + 4, &data, 4);
-	model[7] = '\0';
-
-	/* Retrieve vendor name. */
-	data = be32_to_cpu(fw_dev->config_rom[23]);
-	memcpy(vendor, &data, 4);
-	data = be32_to_cpu(fw_dev->config_rom[24]);
-	memcpy(vendor + 4, &data, 4);
-	vendor[7] = '\0';
+	unsigned int i;
+	u8 c;
+
+	if (fw_dev->config_rom_length < 30) {
+		dev_err(&tscm->unit->device,
+			"Configuration ROM is too short.\n");
+		return -ENODEV;
+	}
+
+	/* Pick up model name from certain addresses. */
+	for (i = 0; i < 8; i++) {
+		c = config_rom[28 + i / 4] >> (24 - 8 * (i % 4));
+		if (c == '\0')
+			break;
+		model[i] = c;
+	}
+	model[i] = '\0';
+
+	for (i = 0; i < ARRAY_SIZE(model_specs); i++) {
+		if (strcmp(model, model_specs[i].name) == 0) {
+			tscm->spec = &model_specs[i];
+			break;
+		}
+	}
+	if (tscm->spec == NULL)
+		return -ENODEV;
 
 	strcpy(tscm->card->driver, "FW-TASCAM");
 	strcpy(tscm->card->shortname, model);
 	strcpy(tscm->card->mixername, model);
 	snprintf(tscm->card->longname, sizeof(tscm->card->longname),
-		 "%s %s, GUID %08x%08x at %s, S%d", vendor, model,
+		 "TASCAM %s, GUID %08x%08x at %s, S%d", model,
 		 cpu_to_be32(fw_dev->config_rom[3]),
 		 cpu_to_be32(fw_dev->config_rom[4]),
 		 dev_name(&tscm->unit->device), 100 << fw_dev->max_speed);
@@ -108,13 +110,12 @@ static int snd_tscm_probe(struct fw_unit *unit,
 	tscm = card->private_data;
 	tscm->card = card;
 	tscm->unit = fw_unit_get(unit);
-	tscm->spec = (const struct snd_tscm_spec *)entry->driver_data;
 
 	mutex_init(&tscm->mutex);
 	spin_lock_init(&tscm->lock);
 	init_waitqueue_head(&tscm->hwdep_wait);
 
-	err = check_name(tscm);
+	err = identify_model(tscm);
 	if (err < 0)
 		goto error;
 
@@ -172,27 +173,12 @@ static void snd_tscm_remove(struct fw_unit *unit)
 }
 
 static const struct ieee1394_device_id snd_tscm_id_table[] = {
-	/* FW-1082 */
-	{
-		.match_flags = IEEE1394_MATCH_VENDOR_ID |
-			       IEEE1394_MATCH_SPECIFIER_ID |
-			       IEEE1394_MATCH_VERSION,
-		.vendor_id = 0x00022e,
-		.specifier_id = 0x00022e,
-		.version = 0x800003,
-		.driver_data = (kernel_ulong_t)&model_specs[2],
-	},
-	/* FW-1884 */
 	{
 		.match_flags = IEEE1394_MATCH_VENDOR_ID |
-			       IEEE1394_MATCH_SPECIFIER_ID |
-			       IEEE1394_MATCH_VERSION,
+			       IEEE1394_MATCH_SPECIFIER_ID,
 		.vendor_id = 0x00022e,
 		.specifier_id = 0x00022e,
-		.version = 0x800000,
-		.driver_data = (kernel_ulong_t)&model_specs[0],
 	},
-	/* FW-1804 mey be supported if IDs are clear. */
 	/* FE-08 requires reverse-engineering because it just has faders. */
 	{}
 };