main: kludge for Pi 5 reboot crashes

The Pi 5 bootloader will leave devices it doesn't care about in the
Addressed state, so tud_mount_cb never gets called. Handoff from the
bootloader to Linux causes a suspend event followed by Reset.

Check if the interface association was configured on entry to Suspend or
Resume. Also, TinyUSB doesn't expose Bus Reset events for whatever
reason, so there's nothing that tears down the interface threads.

Author: P33M

src/main.c

@@ -60,6 +60,8 @@ static uint8_t RxDataBuffer[CFG_TUD_HID_EP_BUFSIZE];
 
 TaskHandle_t dap_taskhandle, tud_taskhandle, mon_taskhandle;
 
+static int was_configured;
+
 void dev_mon(void *ptr)
 {
     uint32_t sof[3];
@@ -224,17 +226,21 @@ bool tud_vendor_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb_control_requ
 void tud_suspend_cb(bool remote_wakeup_en)
 {
   probe_info("Suspended\n");
-  /* Join DAP and UART threads? Or just suspend them, for transparency */
-  vTaskSuspend(uart_taskhandle);
-  vTaskSuspend(dap_taskhandle);
+  /* Were we actually configured? If not, threads don't exist */
+  if (was_configured) {
+	  vTaskSuspend(uart_taskhandle);
+	  vTaskSuspend(dap_taskhandle);
+  }
   /* slow down clk_sys for power saving ? */
 }
 
 void tud_resume_cb(void)
 {
   probe_info("Resumed\n");
-  vTaskResume(uart_taskhandle);
-  vTaskResume(dap_taskhandle);
+  if (was_configured) {
+	  vTaskResume(uart_taskhandle);
+	  vTaskResume(dap_taskhandle);
+  }
 }
 
 void tud_unmount_cb(void)
@@ -244,15 +250,19 @@ void tud_unmount_cb(void)
   vTaskSuspend(dap_taskhandle);
   vTaskDelete(uart_taskhandle);
   vTaskDelete(dap_taskhandle);
+  was_configured = 0;
 }
 
 void tud_mount_cb(void)
 {
   probe_info("Connected, Configured\n");
-  /* UART needs to preempt USB as if we don't, characters get lost */
-  xTaskCreate(cdc_thread, "UART", configMINIMAL_STACK_SIZE, NULL, UART_TASK_PRIO, &uart_taskhandle);
-  /* Lowest priority thread is debug - need to shuffle buffers before we can toggle swd... */
-  xTaskCreate(dap_thread, "DAP", configMINIMAL_STACK_SIZE, NULL, DAP_TASK_PRIO, &dap_taskhandle);
+  if (!was_configured) {
+    /* UART needs to preempt USB as if we don't, characters get lost */
+    xTaskCreate(cdc_thread, "UART", configMINIMAL_STACK_SIZE, NULL, UART_TASK_PRIO, &uart_taskhandle);
+    /* Lowest priority thread is debug - need to shuffle buffers before we can toggle swd... */
+    xTaskCreate(dap_thread, "DAP", configMINIMAL_STACK_SIZE, NULL, DAP_TASK_PRIO, &dap_taskhandle);
+    was_configured = 1;
+  }
 }
 
 void vApplicationTickHook (void)