Implement volume control on default audio HAL

Implemented volume control based on setting audio port config.

Bug: 336370745
Test: atest VtsHalAudioCoreTargetTest
Change-Id: Ia590974e61aa3a1c3f70afdb54ce87c85e9a1b3c
diff --git a/audio/aidl/default/alsa/StreamAlsa.cpp b/audio/aidl/default/alsa/StreamAlsa.cpp
index 372e38a..c77bfca 100644
--- a/audio/aidl/default/alsa/StreamAlsa.cpp
+++ b/audio/aidl/default/alsa/StreamAlsa.cpp
@@ -117,6 +117,7 @@
                                 mReadWriteRetries);
         maxLatency = proxy_get_latency(mAlsaDeviceProxies[0].get());
     } else {
+        alsa::applyGain(buffer, mGain, bytesToTransfer, mConfig.value().format, mConfig->channels);
         for (auto& proxy : mAlsaDeviceProxies) {
             proxy_write_with_retries(proxy.get(), buffer, bytesToTransfer, mReadWriteRetries);
             maxLatency = std::max(maxLatency, proxy_get_latency(proxy.get()));
@@ -166,4 +167,9 @@
     mAlsaDeviceProxies.clear();
 }
 
+ndk::ScopedAStatus StreamAlsa::setGain(float gain) {
+    mGain = gain;
+    return ndk::ScopedAStatus::ok();
+}
+
 }  // namespace aidl::android::hardware::audio::core
diff --git a/audio/aidl/default/alsa/Utils.cpp b/audio/aidl/default/alsa/Utils.cpp
index 8eaf162..10374f2 100644
--- a/audio/aidl/default/alsa/Utils.cpp
+++ b/audio/aidl/default/alsa/Utils.cpp
@@ -22,6 +22,8 @@
 #include <aidl/android/media/audio/common/AudioFormatType.h>
 #include <aidl/android/media/audio/common/PcmType.h>
 #include <android-base/logging.h>
+#include <audio_utils/primitives.h>
+#include <cutils/compiler.h>
 
 #include "Utils.h"
 #include "core-impl/utils.h"
@@ -343,4 +345,68 @@
     return findValueOrDefault(getAudioFormatDescriptorToPcmFormatMap(), aidl, PCM_FORMAT_INVALID);
 }
 
+void applyGain(void* buffer, float gain, size_t bytesToTransfer, enum pcm_format pcmFormat,
+               int channelCount) {
+    if (channelCount != 1 && channelCount != 2) {
+        LOG(WARNING) << __func__ << ": unsupported channel count " << channelCount;
+        return;
+    }
+    if (!getPcmFormatToAudioFormatDescMap().contains(pcmFormat)) {
+        LOG(WARNING) << __func__ << ": unsupported pcm format " << pcmFormat;
+        return;
+    }
+    const float unityGainFloat = 1.0f;
+    if (std::abs(gain - unityGainFloat) < 1e-6) {
+        return;
+    }
+    int numFrames;
+    switch (pcmFormat) {
+        case PCM_FORMAT_S16_LE: {
+            const uint16_t unityGainQ4_12 = u4_12_from_float(unityGainFloat);
+            const uint16_t vl = u4_12_from_float(gain);
+            const uint32_t vrl = (vl << 16) | vl;
+            if (channelCount == 2) {
+                numFrames = bytesToTransfer / sizeof(uint32_t);
+                uint32_t* intBuffer = (uint32_t*)buffer;
+                if (CC_UNLIKELY(vl > unityGainQ4_12)) {
+                    // volume is boosted, so we might need to clamp even though
+                    // we process only one track.
+                    do {
+                        int32_t l = mulRL(1, *intBuffer, vrl) >> 12;
+                        int32_t r = mulRL(0, *intBuffer, vrl) >> 12;
+                        l = clamp16(l);
+                        r = clamp16(r);
+                        *intBuffer++ = (r << 16) | (l & 0xFFFF);
+                    } while (--numFrames);
+                } else {
+                    do {
+                        int32_t l = mulRL(1, *intBuffer, vrl) >> 12;
+                        int32_t r = mulRL(0, *intBuffer, vrl) >> 12;
+                        *intBuffer++ = (r << 16) | (l & 0xFFFF);
+                    } while (--numFrames);
+                }
+            } else {
+                numFrames = bytesToTransfer / sizeof(uint16_t);
+                int16_t* intBuffer = (int16_t*)buffer;
+                if (CC_UNLIKELY(vl > unityGainQ4_12)) {
+                    // volume is boosted, so we might need to clamp even though
+                    // we process only one track.
+                    do {
+                        int32_t mono = mulRL(1, *intBuffer, vrl) >> 12;
+                        *intBuffer++ = clamp16(mono);
+                    } while (--numFrames);
+                } else {
+                    do {
+                        int32_t mono = mulRL(1, *intBuffer, vrl) >> 12;
+                        *intBuffer++ = static_cast<int16_t>(mono & 0xFFFF);
+                    } while (--numFrames);
+                }
+            }
+        } break;
+        default:
+            // TODO(336370745): Implement gain for other supported formats
+            break;
+    }
+}
+
 }  // namespace aidl::android::hardware::audio::core::alsa
diff --git a/audio/aidl/default/alsa/Utils.h b/audio/aidl/default/alsa/Utils.h
index 980f685..a97ea10 100644
--- a/audio/aidl/default/alsa/Utils.h
+++ b/audio/aidl/default/alsa/Utils.h
@@ -59,6 +59,8 @@
     AlsaProxy mProxy;
 };
 
+void applyGain(void* buffer, float gain, size_t bytesToTransfer, enum pcm_format pcmFormat,
+               int channelCount);
 ::aidl::android::media::audio::common::AudioChannelLayout getChannelLayoutMaskFromChannelCount(
         unsigned int channelCount, int isInput);
 ::aidl::android::media::audio::common::AudioChannelLayout getChannelIndexMaskFromChannelCount(