Added DFU runtime implementation to reboot into on-board DFU bootloader, thus new software can be flashed without the BOOT0 jumper over USB.

stm32/aioc-fw/Inc/tusb_config.h

@@ -98,6 +98,7 @@
 #define CFG_TUD_AUDIO             1
 #define CFG_TUD_CDC               1
 #define CFG_TUD_HID               1
+#define CFG_TUD_DFU_RUNTIME       1
 
 // CDC FIFO size of TX and RX
 #define CFG_TUD_CDC_RX_BUFSIZE   128

stm32/aioc-fw/Src/usb_descriptors.c

@@ -112,7 +112,8 @@ uint8_t const * tud_hid_descriptor_report_cb(uint8_t itf)
         TUD_CONFIG_DESC_LEN + \
         AIOC_AUDIO_DESC_LEN + \
         AIOC_HID_DESC_LEN + \
-        AIOC_CDC_DESC_LEN \
+        AIOC_CDC_DESC_LEN + \
+        AIOC_DFU_RT_DESC_LEN \
 )
 
 uint8_t const desc_fs_configuration[] = {
@@ -155,6 +156,16 @@ uint8_t const desc_fs_configuration[] = {
         /* _epout */        EPNUM_CDC_0_OUT,
         /* _epin */         EPNUM_CDC_0_IN,
         /* _epsize */       CFG_TUD_CDC_EP_BUFSIZE
+    ),
+
+    AIOC_DFU_RT_DESCRIPTOR(
+        /* _itfnum */       ITF_NUM_DFU_RT,
+        /* _stridx */       STR_IDX_DFU_RT,
+        /* _attr */         DFU_ATTR_WILL_DETACH | \
+                            DFU_ATTR_CAN_UPLOAD  | \
+                            DFU_ATTR_CAN_DOWNLOAD,
+        /* _timeout */      255, /* not used if WILL_DETACH */
+        /* _xfer_size */    2048 /* max size for stm32 dfu bootloader */
     )
 };
 
@@ -280,6 +291,10 @@ const uint16_t * tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
         len = ascii_to_utf16(ptr, len, USB_STRING_HIDITF);
         break;
 
+    case STR_IDX_DFU_RT:
+        len = ascii_to_utf16(ptr, len, USB_STRING_DFU_RT);
+        break;
+
     default:
         TU_ASSERT(0, NULL);
         break;

stm32/aioc-fw/Src/usb_descriptors.h

@@ -9,6 +9,7 @@ enum USB_DESCRIPTORS_ITF {
     ITF_NUM_HID, /* For CM108 compatibility make this interface #3 */
     ITF_NUM_CDC_0,
     ITF_NUM_CDC_0_DATA,
+    ITF_NUM_DFU_RT,
     ITF_NUM_TOTAL
 };
 
@@ -26,7 +27,8 @@ enum USB_STRING_IDX {
     STR_IDX_AUDIOINCHAN,
     STR_IDX_AUDIOOUTCHAN,
     STR_IDX_HIDITF,
-    STR_IDX_CDCITF
+    STR_IDX_CDCITF,
+    STR_IDX_DFU_RT
 };
 
 #define USB_VID                     0x1209
@@ -44,6 +46,7 @@ enum USB_STRING_IDX {
 #define USB_STRING_AUDIOOUTCHAN     "AIOC Audio Out Channel"
 #define USB_STRING_CDCITF           "AIOC CDC"
 #define USB_STRING_HIDITF           "AIOC HID"
+#define USB_STRING_DFU_RT           "AIOC DFU Runtime"
 
 /* Endpoints */
 #define EPNUM_AUDIO_IN      0x81
@@ -55,7 +58,6 @@ enum USB_STRING_IDX {
 #define EPNUM_CDC_0_IN      0x84
 #define EPNUM_CDC_0_NOTIF   0x85
 
-
 /* Custom Audio Descriptor.
  * Courtesy of https://github.com/hathach/tinyusb/issues/1249#issuecomment-1148727765 */
 #define AUDIO_CTRL_ID_SPK_INPUT_STREAM  0x01
@@ -168,4 +170,8 @@ enum USB_STRING_IDX {
 
 #define AIOC_CDC_DESCRIPTOR TUD_CDC_DESCRIPTOR
 
+#define AIOC_DFU_RT_DESC_LEN   TUD_DFU_RT_DESC_LEN
+
+#define AIOC_DFU_RT_DESCRIPTOR TUD_DFU_RT_DESCRIPTOR
+
 #endif /* USB_DESCRIPTORS_H_ */

stm32/aioc-fw/Src/usb_dfu.c

@@ -0,0 +1,26 @@
+#include "usb_dfu.h"
+#include "stm32f3xx_hal.h"
+#include "tusb.h"
+#include "usb.h"
+
+// Invoked on DFU_DETACH request to reboot to the bootloader
+void tud_dfu_runtime_reboot_to_dfu_cb(void)
+{
+    /* Reset USB and force reset via watchdog timer. */
+    USB_Reset();
+
+    IWDG_HandleTypeDef IWDGHandle = {
+        .Instance = IWDG,
+        .Init = {
+            .Prescaler = IWDG_PRESCALER_4,
+            .Reload = 128,
+            .Window = 0x0FFF
+        }
+    };
+
+    HAL_IWDG_Init(&IWDGHandle);
+
+    while(1) {
+        /* Wait for Reset */
+    }
+}

stm32/aioc-fw/Src/usb_dfu.h

@@ -0,0 +1,4 @@
+#ifndef USB_DFU_H_
+#define USB_DFU_H_
+
+#endif /* USB_DFU_H_ */