Add function to get the ALSA card index for an AVIRT card

From an AVIRT internal card index, we retrieve the ALSA card index.

Signed-off-by: Mark Farrugia <mark.farrugia@fiberdyne.com.au>

2 files changed, 45 insertions, 1 deletions

diff --git a/include/avirt/avirt.h b/include/avirt/avirt.h
index 94f03c5..92eb23c 100644
--- a/include/avirt/avirt.h
+++ b/include/avirt/avirt.h
@@ -65,4 +65,10 @@ int snd_avirt_card_seal();
  */
 int snd_avirt_pcm_info(const char *pcm_name, snd_pcm_info_t *pcm_info);
 
+/**
+ * snd_avirt_card_index_get - Get the ALSA card index for an AVIRT card
+ * @avirt_idx: The AVIRT internal index (TD MF: perhaps change to UID?)
+ * @return: The ALSA card index on success, negative ERRNO otherwise
+ */
+int snd_avirt_card_index_get(int avirt_idx);
 #endif // _AVIRT_H_
diff --git a/src/avirt-config.c b/src/avirt-config.c
index 9bfb4cd..a4a8957 100644
--- a/src/avirt-config.c
+++ b/src/avirt-config.c
@@ -30,7 +30,7 @@
 
 #define AVIRT_CONFIGFS_PATH_STREAMS "/config/snd-avirt/streams/"
 #define AVIRT_CONFIGFS_PATH_MAXLEN 64
-#define AVIRT_DEVICE_PATH "/dev/snd/by-path/platform-snd_avirt.0"
+#define AVIRT_DEVICE_PATH "/dev/snd/by-path/platform-snd_avirt"
 
 #define AVIRT_ERROR(errmsg) \
   fprintf(stderr, "AVIRT ERROR: %s\n", errmsg);
@@ -123,12 +123,50 @@ static int mount_configfs()
   return err;
 }
 
+int snd_avirt_info_get_card(int idx)
+{
+  int open_dev, err = 0;
+  snd_ctl_card_info_t *card_info;
+  char path[64];
+
+  sprintf(path, AVIRT_DEVICE_PATH ".%d", idx);
+  open_dev = open(path, O_RDONLY);
+  if (open_dev < 0)
+  {
+    AVIRT_ERROR_V("Could not open device with path: %s", path);
+    err = -ENODEV;
+    goto exit_dev;
+  }
+
+  snd_ctl_card_info_alloca(&card_info);
+  err = ioctl(open_dev,
+              SNDRV_CTL_IOCTL_CARD_INFO(snd_ctl_card_info_sizeof()),
+              card_info);
+    if (err < 0)
+    {
+      AVIRT_ERROR("Could not ioctl card info for AVIRT");
+      goto exit_dev;
+    }
+
+    return snd_ctl_card_info_get_card(card_info);
+
+exit_dev:
+  close(open_dev);
+
+  return err;
+}
+
 int snd_avirt_pcm_info(const char *pcm_name, snd_pcm_info_t *pcm_info)
 {
   int pcm_dev = -1, err = 0;
   snd_ctl_t *handle;
   char name[32];
 
+  if (card_index < 0)
+    card_index = snd_avirt_info_get_card(0); /* TD MF: Dynamically get the AVIRT card number */
+  if (card_index < 0)
+    return card_index;
+
   sprintf(name, "hw:%d", card_index);
   if ((err = snd_ctl_open(&handle, name, 0)) < 0)
   {