update dma code to use new allocation interface

Author: Randall-Scharpf

ports/atmel-samd/audio_dma.c

@@ -50,8 +50,6 @@ static audio_dma_t *audio_dma_state[AUDIO_DMA_CHANNEL_COUNT];
 // This cannot be in audio_dma_state because it's volatile.
 static volatile bool audio_dma_pending[AUDIO_DMA_CHANNEL_COUNT];
 
-static bool audio_dma_allocated[AUDIO_DMA_CHANNEL_COUNT];
-
 uint8_t find_sync_event_channel_raise() {
     uint8_t event_channel = find_sync_event_channel();
     if (event_channel >= EVSYS_SYNCH_NUM) {
@@ -60,24 +58,6 @@ uint8_t find_sync_event_channel_raise() {
     return event_channel;
 }
 
-uint8_t dma_allocate_channel(void) {
-    uint8_t channel;
-    for (channel = 0; channel < AUDIO_DMA_CHANNEL_COUNT; channel++) {
-        if (!audio_dma_allocated[channel]) {
-            audio_dma_allocated[channel] = true;
-            return channel;
-        }
-    }
-    return channel; // i.e., return failure
-}
-
-void dma_free_channel(uint8_t channel) {
-    assert(channel < AUDIO_DMA_CHANNEL_COUNT);
-    assert(audio_dma_allocated[channel]);
-    audio_dma_disable_channel(channel);
-    audio_dma_allocated[channel] = false;
-}
-
 void audio_dma_disable_channel(uint8_t channel) {
     if (channel >= AUDIO_DMA_CHANNEL_COUNT) {
         return;
@@ -211,7 +191,7 @@ audio_dma_result audio_dma_setup_playback(audio_dma_t *dma,
     bool output_signed,
     uint32_t output_register_address,
     uint8_t dma_trigger_source) {
-    uint8_t dma_channel = dma_allocate_channel();
+    uint8_t dma_channel = dma_allocate_channel(true);
     if (dma_channel >= AUDIO_DMA_CHANNEL_COUNT) {
         return AUDIO_DMA_DMA_BUSY;
     }
@@ -362,8 +342,7 @@ void audio_dma_reset(void) {
     for (uint8_t i = 0; i < AUDIO_DMA_CHANNEL_COUNT; i++) {
         audio_dma_state[i] = NULL;
         audio_dma_pending[i] = false;
-        audio_dma_allocated[i] = false;
-        audio_dma_disable_channel(i);
+        dma_free_channel(i);
         dma_descriptor(i)->BTCTRL.bit.VALID = false;
         MP_STATE_PORT(playing_audio)[i] = NULL;
     }

ports/atmel-samd/audio_dma.h

@@ -68,9 +68,6 @@ uint8_t audiosample_channel_count(mp_obj_t sample_obj);
 void audio_dma_init(audio_dma_t *dma);
 void audio_dma_reset(void);
 
-uint8_t dma_allocate_channel(void);
-void dma_free_channel(uint8_t channel);
-
 // This sets everything up but doesn't start the timer.
 // Sample is the python object for the sample to play.
 // loop is true if we should loop the sample.

ports/atmel-samd/common-hal/audiobusio/PDMIn.c

@@ -384,7 +384,7 @@ static uint16_t filter_sample(uint32_t pdm_samples[4]) {
 // output_buffer_length is the number of slots, not the number of bytes.
 uint32_t common_hal_audiobusio_pdmin_record_to_buffer(audiobusio_pdmin_obj_t *self,
     uint16_t *output_buffer, uint32_t output_buffer_length) {
-    uint8_t dma_channel = dma_allocate_channel();
+    uint8_t dma_channel = dma_allocate_channel(true);
     pdmin_event_channel = find_sync_event_channel_raise();
     pdmin_dma_block_done = false;
 

ports/atmel-samd/common-hal/imagecapture/ParallelImageCapture.c

@@ -155,7 +155,7 @@ void common_hal_imagecapture_parallelimagecapture_singleshot_capture(imagecaptur
     mp_buffer_info_t bufinfo;
     mp_get_buffer_raise(buffer, &bufinfo, MP_BUFFER_RW);
 
-    uint8_t dma_channel = dma_allocate_channel();
+    uint8_t dma_channel = dma_allocate_channel(true);
 
     uint32_t *dest = bufinfo.buf;
     size_t count = bufinfo.len / 4; // PCC receives 4 bytes (2 pixels) at a time