imx233: implement recording side of pcm

Although everything is implemented, recording still doesn't work,
dma is stuck. Add code for reference until this get a proper fix.

Change-Id: Ifc016b00876230c6d337a5cd4f8bb90b856efac8

firmware/target/arm/imx233/pcm-imx233.c

@@ -35,71 +35,124 @@ struct pcm_dma_command_t
 
 __ENSURE_STRUCT_CACHE_FRIENDLY(struct pcm_dma_command_t)
 
-static int locked = 0;
+/* Because we have no way of stopping the DMA properly (see below), we can only
+ * let the tranfer finish on stop. However if the transfer is very long it could
+ * take a while. We work around this by splitting big transfers into small burst
+ * to make sure we can stop quickly. */
+
+static int dac_locked = 0;
 static struct pcm_dma_command_t dac_dma;
-static bool pcm_freezed = false;
+static bool dac_freezed = false;
+
+static const void *dac_buf; /* current buffer */
+static size_t dac_size; /* remaining size */
+
+/* for both recording and playback: maximum transfer size, see
+ * pcm_dma_apply_settings */
+static size_t dma_max_size = CACHEALIGN_UP(1600);
+
+enum
+{
+    DAC_PLAYING,
+    DAC_STOP_PENDING,
+    DAC_STOPPED,
+}dac_state = DAC_STOPPED;
 
 /**
  * WARNING !
  * Never reset the dma channel, otherwise it will halt the DAC for some reason
+ * and I don't know how to recover from this state
  * */
 
-static void play(const void *addr, size_t size)
+static void play(void)
 {
+    /* split transfer if needed */
+    size_t xfer = MIN(dac_size, dma_max_size);
+
     dac_dma.dma.next = NULL;
-    dac_dma.dma.buffer = (void *)addr;
+    dac_dma.dma.buffer = (void *)dac_buf;
     dac_dma.dma.cmd = BF_OR4(APB_CHx_CMD, COMMAND_V(READ),
-        IRQONCMPLT(1), SEMAPHORE(1), XFER_COUNT(size));
+        IRQONCMPLT(1), SEMAPHORE(1), XFER_COUNT(xfer));
     /* dma subsystem will make sure cached stuff is written to memory */
+    dac_state = DAC_PLAYING;
     imx233_dma_start_command(APB_AUDIO_DAC, &dac_dma.dma);
+    /* advance buffer */
+    dac_buf += xfer;
+    dac_size -= xfer;
 }
 
 void INT_DAC_DMA(void)
 {
-    const void *start;
+    /* if stop is pending, ackonowledge stop
-    size_t size;
+     * otherwise try to get some more and stop if there is none */
-
+    if(dac_state == DAC_STOP_PENDING)
-    if(pcm_play_dma_complete_callback(PCM_DMAST_OK, &start, &size))
     {
-        play(start, size);
+        dac_state = DAC_STOPPED;
+    }
+    else if(dac_state == DAC_PLAYING)
+    {
+        /* continue if buffer is not done, otherwise try to get some new data */
+        if(dac_size != 0 || pcm_play_dma_complete_callback(PCM_DMAST_OK, &dac_buf, &dac_size))
+        {
+            play();
             pcm_play_dma_status_callback(PCM_DMAST_STARTED);
         }
+        else
+            dac_state = DAC_STOPPED;
+    }
 
     imx233_dma_clear_channel_interrupt(APB_AUDIO_DAC);
 }
 
 void INT_DAC_ERROR(void)
 {
-    /* TODO: Inform of error through pcm_play_dma_complete_callback */
+    dac_state = DAC_STOPPED;
+    pcm_play_dma_status_callback(PCM_DMAST_ERR_DMA);
+    imx233_dma_clear_channel_interrupt(APB_AUDIO_DAC);
 }
 
 void pcm_play_lock(void)
 {
-    if(locked++ == 0)
+    if(dac_locked++ == 0)
         imx233_dma_enable_channel_interrupt(APB_AUDIO_DAC, false);
 }
 
 void pcm_play_unlock(void)
 {
-    if(--locked == 0)
+    if(--dac_locked == 0)
         imx233_dma_enable_channel_interrupt(APB_AUDIO_DAC, true);
 }
 
 void pcm_play_dma_stop(void)
 {
+    /* do not interrupt the current transaction because resetting the dma
+     * would halt the DAC and clearing RUN causes sound havoc so simply
+     * wait for the end of transfer */
+    pcm_play_lock();
+    dac_buf = NULL;
+    dac_size = 0;
+    dac_state = DAC_STOP_PENDING;
+    pcm_play_unlock();
 }
 
 void pcm_play_dma_start(const void *addr, size_t size)
 {
-    pcm_play_dma_stop();
+    pcm_play_lock();
-
+    /* update pending buffer */
-    play(addr, size);
+    dac_buf = addr;
+    dac_size = size;
+    /* if we are stopped restart playback, otherwise IRQ will pick up */
+    if(dac_state == DAC_STOPPED)
+        play();
+    else
+        dac_state = DAC_PLAYING;
+    pcm_play_unlock();
 }
 
 void pcm_play_dma_pause(bool pause)
 {
     imx233_dma_freeze_channel(APB_AUDIO_DAC, pause);
-    pcm_freezed = pause;
+    dac_freezed = pause;
 }
 
 void pcm_play_dma_init(void)
@@ -117,7 +170,14 @@ void pcm_play_dma_postinit(void)
 
 void pcm_dma_apply_settings(void)
 {
+    pcm_play_lock();
+    /* update frequency */
     audiohw_set_frequency(pcm_fsel);
+    /* compute maximum transfer size: aim at ~1/100s stop time maximum, make sure
+     * the resulting value is a multiple of cache line. At sample rate F we
+     * transfer two samples (2 x 2 bytes) F times per second = 4F b/s */
+    dma_max_size = CACHEALIGN_UP(4 * pcm_sampr / 100);
+    pcm_play_unlock();
 }
 
 size_t pcm_get_bytes_waiting(void)
@@ -128,10 +188,10 @@ size_t pcm_get_bytes_waiting(void)
 
 const void *pcm_play_dma_get_peak_buffer(int *count)
 {
-    if(!pcm_freezed)
+    if(!dac_freezed)
         imx233_dma_freeze_channel(APB_AUDIO_DAC, true);
     struct imx233_dma_info_t info = imx233_dma_get_info(APB_AUDIO_DAC, DMA_INFO_AHB_BYTES | DMA_INFO_BAR);
-    if(!pcm_freezed)
+    if(!dac_freezed)
         imx233_dma_freeze_channel(APB_AUDIO_DAC, false);
     *count = info.ahb_bytes;
     return (void *)info.bar;
@@ -141,39 +201,124 @@ const void *pcm_play_dma_get_peak_buffer(int *count)
  * Recording
  */
 
+/* Because we have no way of stopping the DMA properly (like for the DAC),
+ * we can only let the tranfer finish on stop. However if the transfer is very
+ * long it could take a while. We work around this by splitting big transfers
+ * into small burst to make sure we can stop quickly. */
+
+static int adc_locked = 0;
+static struct pcm_dma_command_t adc_dma;
+
+static void *adc_buf; /* current buffer */
+static size_t adc_size; /* remaining size */
+
+enum
+{
+    ADC_RECORDING,
+    ADC_STOP_PENDING,
+    ADC_STOPPED,
+}adc_state = ADC_STOPPED;
+
 void pcm_rec_lock(void)
 {
+    if(adc_locked++ == 0)
+        imx233_dma_enable_channel_interrupt(APB_AUDIO_ADC, false);
 }
 
+
 void pcm_rec_unlock(void)
 {
+    if(--adc_locked == 0)
+        imx233_dma_enable_channel_interrupt(APB_AUDIO_ADC, true);
 }
 
 void pcm_rec_dma_init(void)
 {
+    imx233_icoll_enable_interrupt(INT_SRC_ADC_DMA, true);
+    imx233_icoll_enable_interrupt(INT_SRC_ADC_ERROR, true);
+    imx233_dma_enable_channel_interrupt(APB_AUDIO_ADC, true);
 }
 
 void pcm_rec_dma_close(void)
 {
+    pcm_rec_dma_stop();
+}
+
+static void rec(void)
+{
+    /* split transfer if needed */
+    size_t xfer = MIN(adc_size, dma_max_size);
+
+    adc_dma.dma.next = NULL;
+    adc_dma.dma.buffer = (void *)adc_buf;
+    adc_dma.dma.cmd = BF_OR4(APB_CHx_CMD, COMMAND_V(WRITE),
+        IRQONCMPLT(1), SEMAPHORE(1), XFER_COUNT(xfer));
+    /* dma subsystem will make sure cached stuff is written to memory */
+    adc_state = ADC_RECORDING;
+    imx233_dma_start_command(APB_AUDIO_ADC, &adc_dma.dma);
+    /* advance buffer */
+    adc_buf += xfer;
+    adc_size -= xfer;
+}
+
+void INT_ADC_DMA(void)
+{
+    /* if stop is pending, ackonowledge stop
+     * otherwise try to get some more and stop if there is none */
+    if(adc_state == ADC_STOP_PENDING)
+    {
+        adc_state = ADC_STOPPED;
+    }
+    else if(adc_state == ADC_RECORDING)
+    {
+        /* continue if buffer is not done, otherwise try to get some new data */
+        if(adc_size != 0 || pcm_rec_dma_complete_callback(PCM_DMAST_OK, &adc_buf, &adc_size))
+        {
+            rec();
+            pcm_rec_dma_status_callback(PCM_DMAST_STARTED);
+        }
+        else
+            adc_state = ADC_STOPPED;
+    }
+
+    imx233_dma_clear_channel_interrupt(APB_AUDIO_ADC);
+}
+
+void INT_ADC_ERROR(void)
+{
+    adc_state = ADC_STOPPED;
+    pcm_rec_dma_status_callback(PCM_DMAST_ERR_DMA);
+    imx233_dma_clear_channel_interrupt(APB_AUDIO_ADC);
 }
 
 void pcm_rec_dma_start(void *addr, size_t size)
 {
-    (void) addr;
+    pcm_rec_lock();
-    (void) size;
+    /* update pending buffer */
+    adc_buf = addr;
+    adc_size = size;
+    /* if we are stopped restart recording, otherwise IRQ will pick up */
+    if(adc_state == ADC_STOPPED)
+        rec();
+    else
+        adc_state = ADC_RECORDING;
+    pcm_rec_unlock();
 }
 
-/*
-void pcm_rec_dma_record_more(void *start, size_t size)
-{
-}
-*/
-
 void pcm_rec_dma_stop(void)
 {
+    /* do not interrupt the current transaction because resetting the dma
+     * would halt the ADC and clearing RUN causes sound havoc so simply
+     * wait for the end of transfer */
+    pcm_rec_lock();
+    adc_buf = NULL;
+    adc_size = 0;
+    adc_state = ADC_STOP_PENDING;
+    pcm_rec_unlock();
 }
 
 const void *pcm_rec_dma_get_peak_buffer(void)
 {
-    return NULL;
+    struct imx233_dma_info_t info = imx233_dma_get_info(APB_AUDIO_ADC, DMA_INFO_BAR);
+    return (void *)info.bar;
 }