Deal with a complication when transferring recording method from PP5024: since the FIFO POP is always read until empty, keep track of sample parity instead of always saving the first one in the FIFO upon entering the ISR or else the first of a duplicate that is also the last in the FIFO would get duplicated. Also, give top priority to audio interrupts in all cases.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@31218 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 42 insertions, 31 deletions

diff --git a/firmware/target/arm/as3525/pcm-as3525.c b/firmware/target/arm/as3525/pcm-as3525.c
index 8b42bbd5b2..b33ea2af84 100644
--- a/firmware/target/arm/as3525/pcm-as3525.c
+++ b/firmware/target/arm/as3525/pcm-as3525.c
@@ -81,7 +81,7 @@ static void play_start_pcm(void)
 
     play_sub_size = size;
 
-    dma_enable_channel(1, (void*)addr, (void*)I2SOUT_DATA, DMA_PERI_I2SOUT,
+    dma_enable_channel(0, (void*)addr, (void*)I2SOUT_DATA, DMA_PERI_I2SOUT,
                 DMAC_FLOWCTRL_DMAC_MEM_TO_PERI, true, false, size >> 2,
                 DMA_S1, dma_callback);
 }
@@ -142,10 +142,10 @@ void pcm_play_dma_stop(void)
 {
     is_playing = false;
 
-    dma_disable_channel(1);
+    dma_disable_channel(0);
 
     /* Ensure byte counts read back 0 */
-    DMAC_CH_SRC_ADDR(1) = 0;
+    DMAC_CH_SRC_ADDR(0) = 0;
     dma_start_addr = NULL;
     dma_start_size = 0;
     dma_rem_size = 0;
@@ -166,7 +166,7 @@ void pcm_play_dma_pause(bool pause)
 
     if(pause)
     {
-        dma_pause_channel(1);
+        dma_pause_channel(0);
 
         /* if producer's buffer finished, upper layer starts anew */
         if (dma_rem_size == 0)
@@ -175,7 +175,7 @@ void pcm_play_dma_pause(bool pause)
     else
     {
         if (play_sub_size != 0)
-            dma_resume_channel(1);
+            dma_resume_channel(0);
         /* else unlock calls the callback if sub buffers remain */
     }
 }
@@ -231,7 +231,7 @@ void pcm_dma_apply_settings(void)
 size_t pcm_get_bytes_waiting(void)
 {
     int oldstatus = disable_irq_save();
-    size_t addr = DMAC_CH_SRC_ADDR(1);
+    size_t addr = DMAC_CH_SRC_ADDR(0);
     size_t start_addr = (size_t)dma_start_addr;
     size_t start_size = dma_start_size;
     restore_interrupt(oldstatus);
@@ -242,7 +242,7 @@ size_t pcm_get_bytes_waiting(void)
 const void * pcm_play_dma_get_peak_buffer(int *count)
 {
     int oldstatus = disable_irq_save();
-    size_t addr = DMAC_CH_SRC_ADDR(1);
+    size_t addr = DMAC_CH_SRC_ADDR(0);
     size_t start_addr = (size_t)dma_start_addr;
     size_t start_size = dma_start_size;
     restore_interrupt(oldstatus);
@@ -269,6 +269,7 @@ void * pcm_dma_addr(void *addr)
 static int rec_locked = 0;
 static uint32_t *rec_dma_addr;
 static size_t rec_dma_size;
+static int keep_sample = 0; /* In nonzero, keep the sample; else, discard it */
 
 void pcm_rec_lock(void)
 {
@@ -310,32 +311,36 @@ void INT_I2SIN(void)
             if (I2SIN_RAW_STATUS & (1<<5))
                 return; /* empty */
 
-            /* Discard every other sample since ADC clock is 1/2 LRCK */
             uint32_t value = *I2SIN_DATA;
-            *I2SIN_DATA;
 
-            /* Data is in left channel only - copy to right channel
-               14-bit => 16-bit samples */
-            value = (uint16_t)(value << 2) | (value << 18);
+            /* Discard every other sample since ADC clock is 1/2 LRCK */
+            keep_sample ^= 1;
 
-            if (audio_output_source != AUDIO_SRC_PLAYBACK && !is_playing)
+            if (keep_sample)
             {
-                /* In this case, loopback is manual so that both output
-                   channels have audio */
-                if (I2SOUT_RAW_STATUS & (1<<5))
+                /* Data is in left channel only - copy to right channel
+                   14-bit => 16-bit samples */
+                value = (uint16_t)(value << 2) | (value << 18);
+
+                if (audio_output_source != AUDIO_SRC_PLAYBACK && !is_playing)
                 {
-                    /* Sync output fifo so it goes empty not before input is
-                       filled */
-                    for (unsigned i = 0; i < 4; i++)
-                        *I2SOUT_DATA = 0;
+                    /* In this case, loopback is manual so that both output
+                       channels have audio */
+                    if (I2SOUT_RAW_STATUS & (1<<5))
+                    {
+                        /* Sync output fifo so it goes empty not before input is
+                           filled */
+                        for (unsigned i = 0; i < 4; i++)
+                            *I2SOUT_DATA = 0;
+                    }
+
+                    *I2SOUT_DATA = value;
+                    *I2SOUT_DATA = value;
                 }
 
-                *I2SOUT_DATA = value;
-                *I2SOUT_DATA = value;
+                *rec_dma_addr++ = value;
+                rec_dma_size -= 4;
             }
-
-            *rec_dma_addr++ = value;
-            rec_dma_size -= 4;
         }
     }
     else
@@ -347,15 +352,19 @@ void INT_I2SIN(void)
             if (I2SIN_RAW_STATUS & (1<<5))
                 return; /* empty */
 
-            /* Discard every other sample since ADC clock is 1/2 LRCK */
             uint32_t value = *I2SIN_DATA;
-            *I2SIN_DATA;
 
-            /* Loopback is in I2S hardware */
+            /* Discard every other sample since ADC clock is 1/2 LRCK */
+            keep_sample ^= 1;
+
+            if (keep_sample)
+            {
+                /* Loopback is in I2S hardware */
 
-            /* 14-bit => 16-bit samples */
-            *rec_dma_addr++ = (value << 2) & ~0x00030000;
-            rec_dma_size -= 4;
+                /* 14-bit => 16-bit samples */
+                *rec_dma_addr++ = (value << 2) & ~0x00030000;
+                rec_dma_size -= 4;
+            }
         }
     }
 
@@ -389,6 +398,8 @@ void pcm_rec_dma_start(void *addr, size_t size)
     rec_dma_addr = addr;
     rec_dma_size = size;
 
+    keep_sample = 0;
+
     /* ensure empty FIFO */
     while (!(I2SIN_RAW_STATUS & (1<<5)))
         *I2SIN_DATA;