Merge pull request #801 from Daft-Freak/pico-extras-dma-sm-alloc

Avoid DMA channel/PIO SM conflicts from scanvideo/audio
32blit · May 17, 2023 · f3333f8 · f3333f8
2 parents 517fa76 + df0272b
commit f3333f8
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Showing 4 changed files with 36 additions and 6 deletions.
diff --git a/32blit-pico/audio_i2s.cpp b/32blit-pico/audio_i2s.cpp
@@ -1,11 +1,15 @@
 #include "audio.hpp"
 #include "config.h"
 
+#include "hardware/dma.h"
+#include "hardware/pio.h"
 #include "pico/audio_i2s.h"
 #define AUDIO_SAMPLE_FREQ 44100
 
 #include "audio/audio.hpp"
 
+#define audio_pio __CONCAT(pio, PICO_AUDIO_I2S_PIO)
+
 static audio_buffer_pool *audio_pool = nullptr;
 
 void init_audio() {
@@ -23,11 +27,18 @@ void init_audio() {
   struct audio_buffer_pool *producer_pool = audio_new_producer_pool(&producer_format, 4, 441);
   const struct audio_format *output_format;
 
+  uint8_t dma_channel = dma_claim_unused_channel(true);
+  uint8_t pio_sm = pio_claim_unused_sm(audio_pio, true);
+
+  // audio_i2s_setup claims
+  dma_channel_unclaim(dma_channel);
+  pio_sm_unclaim(audio_pio, pio_sm);
+
   struct audio_i2s_config config = {
     .data_pin = PICO_AUDIO_I2S_DATA_PIN,
     .clock_pin_base = PICO_AUDIO_I2S_CLOCK_PIN_BASE,
-    .dma_channel = 1,
-    .pio_sm = 1,
+    .dma_channel = dma_channel,
+    .pio_sm = pio_sm,
   };
 
   output_format = audio_i2s_setup(&audio_format, &config);

diff --git a/32blit-pico/audio_pwm.cpp b/32blit-pico/audio_pwm.cpp
@@ -3,12 +3,15 @@
 
 #include "pico/audio_pwm.h"
 #include "hardware/clocks.h"
+#include "hardware/dma.h"
 #include "hardware/pio.h"
 
 #define AUDIO_SAMPLE_FREQ 22050
 
 #include "audio/audio.hpp"
 
+#define audio_pio __CONCAT(pio, PICO_AUDIO_I2S_PIO)
+
 static audio_buffer_pool *audio_pool = nullptr;
 
 void init_audio() {
@@ -26,11 +29,18 @@ void init_audio() {
   struct audio_buffer_pool *producer_pool = audio_new_producer_pool(&producer_format, 4, 441);
   const struct audio_format *output_format;
 
+  uint8_t dma_channel = dma_claim_unused_channel(true);
+  uint8_t pio_sm = pio_claim_unused_sm(audio_pio, true);
+
+  // audio_i2s_setup claims
+  dma_channel_unclaim(dma_channel);
+  pio_sm_unclaim(audio_pio, pio_sm);
+
   struct audio_pwm_channel_config audio_pwm_config = {
     .core = {
       .base_pin = PICO_AUDIO_PWM_MONO_PIN,
-      .dma_channel = 1,
-      .pio_sm = 1,
+      .dma_channel = dma_channel,
+      .pio_sm = pio_sm,
     },
     .pattern = 3,
   };

diff --git a/32blit-pico/display_scanvideo.cpp b/32blit-pico/display_scanvideo.cpp
@@ -1,6 +1,7 @@
 #include "display.hpp"
 
 #include "hardware/clocks.h"
+#include "hardware/dma.h"
 #include "pico/time.h"
 #include "pico/scanvideo.h"
 #include "pico/scanvideo/composable_scanline.h"
@@ -43,7 +44,12 @@ static void fill_scanline_buffer(struct scanvideo_scanline_buffer *buffer) {
 }
 
 void init_display() {
+  // channel 0 get claimed later, channel 3 doesn't get claimed, but does get used
+  // reserve them so out claims don't conflict
+  dma_claim_mask(1 << 0 | 1 << 3);
 
+  // PIO SMs that get claimed later
+  pio_claim_sm_mask(pio0, 1 << 0 | 1 << 3);
 }
 
 void update_display(uint32_t time) {
@@ -56,6 +62,10 @@ void update_display(uint32_t time) {
 }
 
 void init_display_core1() {
+  dma_unclaim_mask(1 << 0 | 1 << 3);
+  pio_sm_unclaim(pio0,  0);
+  pio_sm_unclaim(pio0,  3);
+
   // no mode switching yet
 #if ALLOW_HIRES
 #if DISPLAY_HEIGHT == 160 // extra middle mode

diff --git a/32blit-pico/main.cpp b/32blit-pico/main.cpp
@@ -182,6 +182,7 @@ int main() {
   init_input();
   init_fs();
   init_usb();
+  init_audio();
 
 #if defined(ENABLE_CORE1)
   multicore_launch_core1(core1_main);
@@ -192,8 +193,6 @@ int main() {
   blit::render = ::render;
   blit::update = ::update;
 
-  init_audio();
-
   // user init
   ::init();