aaf: Load configuration parameters

This patch implements the infrastructure to load the plugin
configuration from ALSA configuration file. The configuration
is loaded in open() callback.

All configuration parameters are described in details in doc/aaf.txt
file.

Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/aaf/pcm_aaf.c b/aaf/pcm_aaf.c
index 31d8759bf8773848f2a3ff0bb2097ce24443f6a8..c9d4b70ece80685a55a61b4a1b997220c8c5f1ba 100644 (file)
--- a/aaf/pcm_aaf.c
+++ b/aaf/pcm_aaf.c
@@ -20,11 +20,138 @@
 
 #include <alsa/asoundlib.h>
 #include <alsa/pcm_external.h>
+#include <linux/if_ether.h>
+#include <net/if.h>
+#include <string.h>
+#include <stdint.h>
+
+#define NSEC_PER_USEC 1000
 
 typedef struct {
        snd_pcm_ioplug_t io;
+
+       char ifname[IFNAMSIZ];
+       unsigned char addr[ETH_ALEN];
+       int prio;
+       uint64_t streamid;
+       int mtt;
+       int t_uncertainty;
+       snd_pcm_uframes_t frames_per_pdu;
 } snd_pcm_aaf_t;
 
+static int aaf_load_config(snd_pcm_aaf_t *aaf, snd_config_t *conf)
+{
+       snd_config_iterator_t cur, next;
+
+       snd_config_for_each(cur, next, conf) {
+               snd_config_t *entry = snd_config_iterator_entry(cur);
+               const char *id;
+
+               if (snd_config_get_id(entry, &id) < 0)
+                       goto err;
+
+               if (strcmp(id, "comment") == 0 ||
+                   strcmp(id, "type") == 0 ||
+                   strcmp(id, "hint") == 0)
+                       continue;
+
+               if (strcmp(id, "ifname") == 0) {
+                       const char *ifname;
+
+                       if (snd_config_get_string(entry, &ifname) < 0)
+                               goto err;
+
+                       snprintf(aaf->ifname, sizeof(aaf->ifname), "%s",
+                                ifname);
+               } else if (strcmp(id, "addr") == 0) {
+                       const char *addr;
+                       int n;
+
+                       if (snd_config_get_string(entry, &addr) < 0)
+                               goto err;
+
+                       n = sscanf(addr, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
+                                  &aaf->addr[0], &aaf->addr[1],
+                                  &aaf->addr[2], &aaf->addr[3],
+                                  &aaf->addr[4], &aaf->addr[5]);
+                       if (n != 6)
+                               goto err;
+               } else if (strcmp(id, "prio") == 0) {
+                       long prio;
+
+                       if (snd_config_get_integer(entry, &prio) < 0)
+                               goto err;
+
+                       if (prio < 0)
+                               goto err;
+
+                       aaf->prio = prio;
+               } else if (strcmp(id, "streamid") == 0) {
+                       const char *streamid;
+                       unsigned char addr[6];
+                       unsigned short unique_id;
+                       int n;
+
+                       if (snd_config_get_string(entry, &streamid) < 0)
+                               goto err;
+
+                       n = sscanf(streamid,
+                                  "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx:%hx",
+                                  &addr[0], &addr[1], &addr[2], &addr[3],
+                                  &addr[4], &addr[5], &unique_id);
+                       if (n != 7)
+                               goto err;
+
+                       aaf->streamid = (uint64_t) addr[0] << 56 |
+                                       (uint64_t) addr[1] << 48 |
+                                       (uint64_t) addr[2] << 40 |
+                                       (uint64_t) addr[3] << 32 |
+                                       (uint64_t) addr[4] << 24 |
+                                       (uint64_t) addr[5] << 16 |
+                                       unique_id;
+               } else if (strcmp(id, "mtt") == 0) {
+                       long mtt;
+
+                       if (snd_config_get_integer(entry, &mtt) < 0)
+                               goto err;
+
+                       if (mtt < 0)
+                               goto err;
+
+                       aaf->mtt = mtt * NSEC_PER_USEC;
+               } else if (strcmp(id, "time_uncertainty") == 0) {
+                       long t_uncertainty;
+
+                       if (snd_config_get_integer(entry, &t_uncertainty) < 0)
+                               goto err;
+
+                       if (t_uncertainty < 0)
+                               goto err;
+
+                       aaf->t_uncertainty = t_uncertainty * NSEC_PER_USEC;
+               } else if (strcmp(id, "frames_per_pdu") == 0) {
+                       long frames_per_pdu;
+
+                       if (snd_config_get_integer(entry, &frames_per_pdu) < 0)
+                               goto err;
+
+                       if (frames_per_pdu < 0)
+                               goto err;
+
+                       aaf->frames_per_pdu = frames_per_pdu;
+               } else {
+                       SNDERR("Invalid configuration: %s", id);
+                       goto err;
+               }
+       }
+
+       return 0;
+
+err:
+       SNDERR("Error loading device configuration");
+       return -EINVAL;
+}
+
 static int aaf_close(snd_pcm_ioplug_t *io)
 {
        free(io->private_data);
@@ -64,6 +191,10 @@ SND_PCM_PLUGIN_DEFINE_FUNC(aaf)
                return -ENOMEM;
        }
 
+       res = aaf_load_config(aaf, conf);
+       if (res < 0)
+               goto err;
+
        aaf->io.version = SND_PCM_IOPLUG_VERSION;
        aaf->io.name = "AVTP Audio Format (AAF) Plugin";
        aaf->io.callback = &aaf_callback;

diff --git a/configure.ac b/configure.ac
index db36f0316b3f8ed4fc7d98d07a94b906fd912141..eadaed62bc08a74ee7d7836ff64f487cc907070d 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -181,6 +181,7 @@ AC_ARG_ENABLE([aaf],
 
 if test "x$enable_aaf" != "xno"; then
   PKG_CHECK_MODULES(AVTP, avtp >= 0.1, [HAVE_AAF=yes], [HAVE_AAF=no])
+  AC_CHECK_HEADERS([linux/if_ether.h], [], [HAVE_AAF=no])
 fi
 AM_CONDITIONAL(HAVE_AAF, test x$HAVE_AAF = xyes)
 

diff --git a/doc/aaf.txt b/doc/aaf.txt
index b260a26cf962e6d8eb190c1e1f86b4e17a48843e..afc794b3052149f3c631fe58ff4b0a5ae53c8956 100644 (file)
--- a/doc/aaf.txt
+++ b/doc/aaf.txt
@@ -14,5 +14,36 @@ Plugin Dependencies
 
 The AAF plugin uses libavtp to handle AVTP packetization. Libavtp source code
 can be found in https://github.com/AVnu/libavtp as well as instructions to
-build and install it. If libavtp isn't detected by configure, the plugin isn't
+build and install it.
+
+The plugin also depends on some kernel API headers such as linux/if_ether.h so
+make sure you have them installed in your system.
+
+If libavtp or the kernel headers aren't detected by configure, the plugin isn't
 built.
+
+Plugin Configuration
+--------------------
+
+The plugin parameters are passed via ALSA configuration file. They are defined
+as follows:
+
+       * ifname: Network interface used to transmit/receive AVTP packets.
+
+       * addr: Stream destination MAC address.
+
+       * prio: Priority used by the plugin to transmit AVTP traffic. This
+         option is relevant only when operating in playback mode.
+
+       * streamid: Stream ID associated with the AAF stream transmitted or
+         received by the plugin.
+
+       * mtt: Maximum Transit Time (in microseconds) as defined in AVTP spec
+         section 4.3.3. This option is relevant only when operating in
+         playback mode.
+
+       * time_uncertainty: Maximum Time Uncertainty (in microseconds) as
+         defined by AVTP spec section 4.3.3. This option is relevant only when
+         operating in playback mode.
+
+       * frames_per_pdu: Number of audio frames transmitted in one AVTPDU.