Fix save config (#27)

* Fix save config

* Fix save config when no audio is playing

* Fix build issue with the github workflow compiler

firmware/code/configuration_manager.c

@@ -96,6 +96,13 @@ static bool reload_config = false;
 static uint16_t write_offset = 0;
 static uint16_t read_offset = 0;
 
+typedef enum {
+    NormalOperation,
+    SaveRequested,
+    Saving
+} State;
+static State saveState = NormalOperation;
+
 bool validate_filter_configuration(filter_configuration_tlv *filters)
 {
     if (filters->header.type != FILTER_CONFIGURATION) {
@@ -357,14 +364,16 @@ void load_config() {
 }
 
 #ifndef TEST_TARGET
-bool __no_inline_not_in_flash_func(save_configuration)() {
+bool __no_inline_not_in_flash_func(save_config)() {
-
-
-    
     const uint8_t active_configuration = inactive_working_configuration ? 0 : 1;
     tlv_header* config = (tlv_header*) working_configuration[active_configuration];
 
+    switch (saveState) {
+        case SaveRequested:
             if (validate_configuration(config)) {      
+                /* Turn the DAC off so we don't make a huge noise when disrupting
+                real time audio operation. */
+                power_down_dac();
 
                 const size_t config_length = config->length - ((size_t)config->value - (size_t)config);
                 // Write data to flash
@@ -376,19 +385,27 @@ bool __no_inline_not_in_flash_func(save_configuration)() {
                 flash_header->version = CONFIG_VERSION;
                 memcpy((void*)(flash_header->tlvs), config->value, config_length);
 
-        /* Turn the DAC off so we don't make a huge noise when disrupting
-           real time audio operation. */
-        power_down_dac();
-
                 uint32_t ints = save_and_disable_interrupts();
                 flash_range_erase(USER_CONFIGURATION_OFFSET, FLASH_SECTOR_SIZE);
                 flash_range_program(USER_CONFIGURATION_OFFSET, flash_buffer, CFG_BUFFER_SIZE);
                 restore_interrupts(ints);
+                saveState = Saving;
 
-        power_up_dac();
+                // Return true, so the caller skips processing audio
-
                 return true;
             }
+            // Validation failed, give up.
+            saveState = NormalOperation;
+            break;
+        case Saving:
+            /* Turn the DAC off so we don't make a huge noise when disrupting
+            real time audio operation. */
+            power_up_dac();
+            saveState = NormalOperation;
+            return false;
+        default:
+            break;
+    }
 
     return false;
 }
@@ -415,7 +432,14 @@ bool process_cmd(tlv_header* cmd) {
             }
             break;
         case SAVE_CONFIGURATION: {
-            if (cmd->length == 4 && save_configuration()) {
+            if (cmd->length == 4) {
+                saveState = SaveRequested;
+                if (audio_state.interface == 0) {
+                    // The OS will configure the alternate "zero" interface when the device is not in use
+                    // in this sate we can write to flash now. Otherwise, defer the save until we get the next
+                    // usb packet.
+                    save_config();
+                }
                 result->type = OK;
                 result->length = 4;
                 return true;

firmware/code/configuration_manager.h

@@ -52,6 +52,7 @@ void config_in_packet(struct usb_endpoint *ep);
 void config_out_packet(struct usb_endpoint *ep);
 void configuration_ep_on_cancel(struct usb_endpoint *ep);
 extern void load_config();
+extern bool save_config();
 extern void apply_config_changes();
 
 #endif // CONFIGURATION_MANAGER_H

firmware/code/run.c

@@ -52,6 +52,7 @@ static uint8_t *userbuf;
 audio_state_config audio_state = {
     .freq = 48000,
     .de_emphasis_frequency = 0x1, // 48khz
+    .interface = 0
 };
 
 preprocessing_config preprocessing = {
@@ -125,6 +126,18 @@ static void __no_inline_not_in_flash_func(_as_audio_packet)(struct usb_endpoint
     int32_t *out = (int32_t *) userbuf;
     int samples = usb_buffer->data_len / 2;
 
+    // Make sure core 1 is ready for us.
+    multicore_fifo_pop_blocking();
+
+    if (save_config()) {
+        // Skip processing while we are writing to flash
+        multicore_fifo_push_blocking(CORE0_ABORTED);
+        // keep on truckin'
+        usb_grow_transfer(ep->current_transfer, 1);
+        usb_packet_done(ep);
+        return;
+    }
+
     if (preprocessing.reverse_stereo) {
         for (int i = 0; i < samples; i+=2) {
             out[i] = in[i+1];
@@ -136,8 +149,6 @@ static void __no_inline_not_in_flash_func(_as_audio_packet)(struct usb_endpoint
             out[i] = in[i];
     }
  
-    // Make sure core 1 is ready for us.
-    multicore_fifo_pop_blocking();
     multicore_fifo_push_blocking(CORE0_READY);
     multicore_fifo_push_blocking(samples);
 
@@ -186,8 +197,7 @@ void __no_inline_not_in_flash_func(core1_entry)() {
 
         // Block until the userbuf is filled with data
         uint32_t ready = multicore_fifo_pop_blocking();
-        while (ready != CORE0_READY)
+        if (ready == CORE0_ABORTED) continue;
-            ready = multicore_fifo_pop_blocking();
         
         const uint32_t samples = multicore_fifo_pop_blocking();
 
@@ -760,6 +770,7 @@ static const struct usb_transfer_type _audio_cmd_transfer_type = {
 
 static bool as_set_alternate(struct usb_interface *interface, uint alt) {
     assert(interface == &as_op_interface);
+    audio_state.interface = alt;
     switch (alt) {
         case 0: power_down_dac(); return true;
         case 1: power_up_dac(); return true;

firmware/code/run.h

@@ -76,6 +76,7 @@ typedef struct _audio_state_config {
         int16_t _target_pcm3060_registers;
     };
     int16_t pcm3060_registers;
+    int8_t interface;
 } audio_state_config;
 extern audio_state_config audio_state;
 
@@ -149,6 +150,7 @@ static char *descriptor_strings[] = {
 #define SAMPLING_FREQ (CODEC_FREQ / 192)
 
 #define CORE0_READY 19813219
+#define CORE0_ABORTED 91231891
 #define CORE1_READY 72965426
 
 /*****************************************************************************