ALSA: dice: fix device detection for other vendors

DICE devices do not have a unique specifier ID in their unit directory
(it's always the same as the device vendor's ID), so rely on just the
version ID for driver loading, and use a heuristic in the probe callback
to detect actual DICE devices.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

1 files changed, 84 insertions, 18 deletions

diff --git a/sound/firewire/dice.c b/sound/firewire/dice.c
index 1da1ddefd6a8..b4827ff45d68 100644
--- a/sound/firewire/dice.c
+++ b/sound/firewire/dice.c
@@ -827,28 +827,93 @@ static void dice_card_free(struct snd_card *card)
         mutex_destroy(&dice->mutex);
 }
 
+#define DICE_CATEGORY_ID 0x04
+
+static int dice_interface_check(struct fw_unit *unit)
+{
+        static const int min_values[10] = {
+                10, 0x64 / 4,
+                10, 0x18 / 4,
+                10, 0x18 / 4,
+                0, 0,
+                0, 0,
+        };
+        struct fw_device *device = fw_parent_device(unit);
+        struct fw_csr_iterator it;
+        int key, value, vendor = -1, model = -1, err;
+        unsigned int i;
+        __be32 pointers[ARRAY_SIZE(min_values)];
+        __be32 version;
+
+        /*
+         * Check that GUID and unit directory are constructed according to DICE
+         * rules, i.e., that the specifier ID is the GUID's OUI, and that the
+         * GUID chip ID consists of the 8-bit DICE category ID, the 10-bit
+         * product ID, and a 22-bit serial number.
+         */
+        fw_csr_iterator_init(&it, unit->directory);
+        while (fw_csr_iterator_next(&it, &key, &value)) {
+                switch (key) {
+                case CSR_SPECIFIER_ID:
+                        vendor = value;
+                        break;
+                case CSR_MODEL:
+                        model = value;
+                        break;
+                }
+        }
+        if (device->config_rom[3] != ((vendor << 8) | DICE_CATEGORY_ID) ||
+            device->config_rom[4] >> 22 != model)
+                return -ENODEV;
+
+        /*
+         * Check that the sub address spaces exist and are located inside the
+         * private address space.  The minimum values are chosen so that all
+         * minimally required registers are included.
+         */
+        err = snd_fw_transaction(unit, TCODE_READ_BLOCK_REQUEST,
+                                 DICE_PRIVATE_SPACE,
+                                 pointers, sizeof(pointers));
+        if (err < 0)
+                return -ENODEV;
+        for (i = 0; i < ARRAY_SIZE(pointers); ++i) {
+                value = be32_to_cpu(pointers[i]);
+                if (value < min_values[i] || value >= 0x40000)
+                        return -ENODEV;
+        }
+
+        /*
+         * Check that the implemented DICE driver specification major version
+         * number matches.
+         */
+        err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
+                                 DICE_PRIVATE_SPACE +
+                                 be32_to_cpu(pointers[0]) * 4 + GLOBAL_VERSION,
+                                 &version, 4);
+        if (err < 0)
+                return -ENODEV;
+        if ((version & cpu_to_be32(0xff000000)) != cpu_to_be32(0x01000000)) {
+                dev_err(&unit->device,
+                        "unknown DICE version: 0x%08x\n", be32_to_cpu(version));
+                return -ENODEV;
+        }
+
+        return 0;
+}
+
 static int dice_init_offsets(struct dice *dice)
 {
         __be32 pointers[6];
-        unsigned int global_size, rx_size;
         int err;
 
         err = snd_fw_transaction(dice->unit, TCODE_READ_BLOCK_REQUEST,
-                                 DICE_PRIVATE_SPACE, &pointers, 6 * 4);
+                                 DICE_PRIVATE_SPACE,
+                                 pointers, sizeof(pointers));
         if (err < 0)
                 return err;
 
         dice->global_offset = be32_to_cpu(pointers[0]) * 4;
-        global_size = be32_to_cpu(pointers[1]);
         dice->rx_offset = be32_to_cpu(pointers[4]) * 4;
-        rx_size = be32_to_cpu(pointers[5]);
-
-        /* some sanity checks to ensure that we actually have a DICE */
-        if (dice->global_offset < 10 * 4 || global_size < 0x168 / 4 ||
-            dice->rx_offset < 10 * 4 || rx_size < 0x120 / 4) {
-                dev_err(&dice->unit->device, "invalid register pointers\n");
-                return -ENXIO;
-        }
 
         return 0;
 }
@@ -881,8 +946,8 @@ static void dice_card_strings(struct dice *dice)
         strcpy(model, "?");
         fw_csr_string(dice->unit->directory, CSR_MODEL, model, sizeof(model));
         snprintf(card->longname, sizeof(card->longname),
-                 "%s %s, GUID %08x%08x at %s, S%d",
-                 vendor, model, dev->config_rom[3], dev->config_rom[4],
+                 "%s %s (serial %u) at %s, S%d",
+                 vendor, model, dev->config_rom[4] & 0x3fffff,
                  dev_name(&dice->unit->device), 100 << dev->max_speed);
 
         strcpy(card->mixername, "DICE");
@@ -895,6 +960,10 @@ static int dice_probe(struct fw_unit *unit, const struct ieee1394_device_id *id)
         __be32 clock_sel;
         int err;
 
+        err = dice_interface_check(unit);
+        if (err < 0)
+                return err;
+
         err = snd_card_create(-1, NULL, THIS_MODULE, sizeof(*dice), &card);
         if (err < 0)
                 return err;
@@ -1020,15 +1089,12 @@ static void dice_bus_reset(struct fw_unit *unit)
         mutex_unlock(&dice->mutex);
 }
 
-#define TC_OUI          0x000166
 #define DICE_INTERFACE  0x000001
 
 static const struct ieee1394_device_id dice_id_table[] = {
         {
-                .match_flags  = IEEE1394_MATCH_SPECIFIER_ID |
-                                IEEE1394_MATCH_VERSION,
-                .specifier_id = TC_OUI,
-                .version      = DICE_INTERFACE,
+                .match_flags = IEEE1394_MATCH_VERSION,
+                .version     = DICE_INTERFACE,
         },
         { }
 };