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diff --git a/docs/3.Usage.md b/docs/3.Usage.md new file mode 100644 index 0000000..ba5c3e6 --- /dev/null +++ b/docs/3.Usage.md @@ -0,0 +1,140 @@ +Using AVIRT +=================================== + +## Introduction + +## Table of Contents + +1. [Load/Unload AVIRT](#un-load-avirt) +2. [Configuring AVIRT](#configuring-avirt) +3. [Checking AVIRT](#checking-avirt) + +<a name="un-load-avirt"/> + +## 1. Loading and Unloading AVIRT + +### Load Out of Tree + +As root, load the required `avirt_core.ko` and subsequent audio path. +As an example, the Dummy Audiopath is being loaded here. + +```sh +insmod snd-avirt-core.ko +insmod dummy/snd-avirt-ap-dummy.ko +insmod loopback/snd-avirt-ap-loopback.ko +``` + +### Note: + +The loading and unloading of drivers can be performed using the helper scripts. +To run, we must load the kernel modules using the `scripts/load.sh` script: + +```sh +$ ./scripts/load.sh +``` + +To unload the drivers use: + +```sh +$ ./scripts/unload.sh +``` + +### Load In Tree + +#### Note: + +Either build the module in tree, or you can copy the modules manually and then run `depmod` to generate dependencies. +For example, in AGL: + +```sh +mkdir -p /lib/modules/$(uname -r)/extra +cp snd-avirt-core.ko snd-avirt-ap-dummy.ko snd-avirt-ap-loopback.ko /lib/modules/$(uname -r)/extra +depmod +``` + +Once the modules are in place, we can load the modules using: + +```sh +modprobe snd-avirt-core +modprobe snd-avirt-ap-dummy +modprobe snd-avirt-ap-loopback +``` + +<a name="configure-avirt" /> + +## 2. Configuring AVIRT + +AVIRT is configured using configfs. + +### Note: + +A sample script for the following is supplied inside the `scripts` folder. + +First, verify the kernel supports the use of configfs. + +```sh +fgrep configfs /proc/filesystems +``` + +The expected output is: + +``` +nodev configfs +``` + +Once confirmed, we can mount the `configfs` filesystem at the conventional point: + +```sh +# Check configfs is mounted on the system +mkdir -p /config +mount -t configfs none /config +``` + +Finally, we can configure AVIRT, for example: + +```sh +# Set up each of the cards channels +mkdir /config/snd-avirt/streams/playback_media +echo "2">/config/snd-avirt/streams/playback_media/channels +echo "ap_dummy">/config/snd-avirt/streams/playback_media/map + +mkdir /config/snd-avirt/streams/playback_navigation +echo "1">/config/snd-avirt/streams/playback_navigation/channels +echo "ap_dummy">/config/snd-avirt/streams/playback_navigation/map + +mkdir /config/snd-avirt/streams/playback_emergency +echo "1">/config/snd-avirt/streams/playback_emergency/channels +echo "ap_dummy">/config/snd-avirt/streams/playback_emergency/map + +mkdir /config/snd-avirt/streams/capture_voice +echo "1">/config/snd-avirt/streams/capture_voice/channels +echo "ap_dummy">/config/snd-avirt/streams/capture_voice/map + +# Finally, seal the card, and initiate configuration +echo "1">/config/snd-avirt/streams/sealed +``` + +Alternatively, the test script at `scripts/test_configfs.sh` can be used. + +The user-space library, [libavirt](https://github.com/fiberdyne/libavirt) can be used to interact with the configfs interface. Please refer to the README in libavirt for further details. + +<a name="checking-avirt" /> + +## 3. Checking AVIRT Loaded Correctly + +We can see the newly created streams by using the `aplay` utility. For example, the device list might look a little like this: + +```sh +aplay -l +... +card 2: avirt [avirt], device 0: multimedia [multimedia] + Subdevices: 1/1 + Subdevice #0: subdevice #0 +card 2: avirt [avirt], device 1: navigation [navigation] + Subdevices: 1/1 + Subdevice #0: subdevice #0 +card 2: avirt [avirt], device 2: emergency [emergency] + Subdevices: 1/1 + Subdevice #0: subdevice #0 +... +``` |