stm32: Fix init sequence of USB hardware and TinyUSB stack.

This commit fixes the initialization sequence for TinyUSB when enabled on
the stm32 port:

- Following other ports, `mp_usbd_init()` should be called just after
  running `boot.py`, to give the user a chance to configure USB.

- Hardware initialization (via `pyb_usbd_init()`) should only occur once,
  the first time TinyUSB is started up.  This is achieved by adding a hook
  to the shared TinyUSB bindings to call `pyb_usbd_init()`, and only do the
  hardware init if TinyUSB was not already initialized.

Also, `pyb_usbd_init()` is renamed `mp_usbd_ll_init()` to make it match
with the rest of the stared TinyUSB binding code.

Signed-off-by: Damien George <damien@micropython.org>

ports/stm32/main.c

@@ -611,14 +611,9 @@ soft_reset:
     pyb_can_init0();
     #endif
 
-    #if MICROPY_HW_ENABLE_USB
+    #if MICROPY_HW_STM_USB_STACK && MICROPY_HW_ENABLE_USB
-    #if MICROPY_HW_TINYUSB_STACK
-    pyb_usbd_init();
-    mp_usbd_init();
-    #else
     pyb_usb_init0();
     #endif
-    #endif
 
     #if MICROPY_PY_MACHINE_I2S
     machine_i2s_init0();
@@ -690,6 +685,10 @@ soft_reset:
     }
     #endif
 
+    #if MICROPY_HW_TINYUSB_STACK && MICROPY_HW_ENABLE_USBDEV
+    mp_usbd_init();
+    #endif
+
     #if MICROPY_HW_HAS_MMA7660
     // MMA accel: init and reset
     accel_init();

ports/stm32/mpconfigboard_common.h

@@ -261,6 +261,7 @@
 #if MICROPY_HW_TINYUSB_STACK
 #ifndef MICROPY_HW_ENABLE_USBDEV
 #define MICROPY_HW_ENABLE_USBDEV (1)
+#define MICROPY_HW_TINYUSB_LL_INIT mp_usbd_ll_init
 #endif
 
 #ifndef MICROPY_HW_USB_CDC

ports/stm32/mphalport.h

@@ -1,6 +1,7 @@
 // We use the ST Cube HAL library for most hardware peripherals
 #include STM32_HAL_H
 #include "pin.h"
+#include "usbd_conf.h"
 #include "py/ringbuf.h"
 #include "shared/runtime/interrupt_char.h"
 

ports/stm32/usbd_conf.c

@@ -32,6 +32,7 @@
 #include "usbd_core.h"
 #include "py/obj.h"
 #include "py/mphal.h"
+#include "shared/tinyusb/mp_usbd.h"
 #include "irq.h"
 #include "usb.h"
 
@@ -334,7 +335,12 @@ static void mp_usbd_ll_init_hs(void) {
 
 #if MICROPY_HW_TINYUSB_STACK
 
-void pyb_usbd_init(void) {
+void mp_usbd_ll_init(void) {
+    // Only initialize the USB hardware once.
+    if (tusb_inited()) {
+        return;
+    }
+
     #if MICROPY_HW_USB_FS
     mp_usbd_ll_init_fs();
     #endif

ports/stm32/usbd_conf.h

@@ -65,7 +65,7 @@
 #define USBD_HS_NUM_FIFO                      (1 + USBD_HS_NUM_TX_FIFO)
 
 #if MICROPY_HW_TINYUSB_STACK
-void pyb_usbd_init(void);
+void mp_usbd_ll_init(void);
 #endif
 
 #endif // MICROPY_INCLUDED_STM32_USBD_CONF_H