ports: On cold boot, enable USB after boot.py completes.

For mimxrt, nrf, renesas-ra, rp2 and samd ports, this commit implements
similar behaviour to the stm32 port, where USB is only brought up after
boot.py completes execution.

Currently this doesn't add any useful functionality (and may break
workflows that depend on USB-CDC being live in boot.py), however it's a
precondition for more usable workflows with USB devices defined in
Python (allows setting up USB interfaces in boot.py before the device
enumerates for the first time).

This work was funded through GitHub Sponsors.

Signed-off-by: Angus Gratton <angus@redyak.com.au>

ports/mimxrt/main.c

@@ -34,8 +34,8 @@
 #include "shared/runtime/gchelper.h"
 #include "shared/runtime/pyexec.h"
 #include "shared/runtime/softtimer.h"
+#include "shared/tinyusb/mp_usbd.h"
 #include "ticks.h"
-#include "tusb.h"
 #include "led.h"
 #include "pendsv.h"
 #include "modmachine.h"
@@ -63,7 +63,6 @@ void board_init(void);
 int main(void) {
     board_init();
     ticks_init();
-    tusb_init();
     pendsv_init();
 
     #if MICROPY_PY_LWIP
@@ -115,6 +114,9 @@ int main(void) {
 
         // Execute user scripts.
         int ret = pyexec_file_if_exists("boot.py");
+
+        mp_usbd_init();
+
         if (ret & PYEXEC_FORCED_EXIT) {
             goto soft_reset_exit;
         }

ports/nrf/drivers/usb/usb_cdc.c

@@ -29,14 +29,14 @@
 
 #if MICROPY_HW_USB_CDC
 
-#include "tusb.h"
 #include "nrfx.h"
 #include "nrfx_power.h"
 #include "nrfx_uart.h"
 #include "py/ringbuf.h"
 #include "py/stream.h"
 #include "py/runtime.h"
 #include "shared/runtime/interrupt_char.h"
+#include "shared/tinyusb/mp_usbd.h"
 
 #ifdef BLUETOOTH_SD
 #include "nrf_sdm.h"
@@ -186,7 +186,7 @@ int usb_cdc_init(void)
     tx_ringbuf.iget = 0;
     tx_ringbuf.iput = 0;
 
-    tusb_init();
+    mp_usbd_init();
 
     return 0;
 }

ports/nrf/main.c

@@ -261,13 +261,15 @@ void NORETURN _start(void) {
 
     led_state(1, 0);
 
+    #if MICROPY_VFS || MICROPY_MBFS || MICROPY_MODULE_FROZEN
+    ret = pyexec_file_if_exists("boot.py");
+    #endif
+
     #if MICROPY_HW_USB_CDC
     usb_cdc_init();
     #endif
 
     #if MICROPY_VFS || MICROPY_MBFS || MICROPY_MODULE_FROZEN
-    // run boot.py and main.py if they exist.
-    ret = pyexec_file_if_exists("boot.py");
     if (pyexec_mode_kind == PYEXEC_MODE_FRIENDLY_REPL && ret != 0) {
         pyexec_file_if_exists("main.py");
     }

ports/renesas-ra/main.c

@@ -36,6 +36,7 @@
 #include "shared/readline/readline.h"
 #include "shared/runtime/pyexec.h"
 #include "shared/runtime/softtimer.h"
+#include "shared/tinyusb/mp_usbd.h"
 #include "lib/oofatfs/ff.h"
 #include "lib/littlefs/lfs1.h"
 #include "lib/littlefs/lfs1_util.h"
@@ -63,7 +64,6 @@
 #include "usrsw.h"
 #include "rtc.h"
 #include "storage.h"
-#include "tusb.h"
 #if MICROPY_PY_LWIP
 #include "lwip/init.h"
 #include "lwip/apps/mdns.h"
@@ -270,10 +270,6 @@ int main(void) {
     state.reset_mode = 1;
     state.log_soft_reset = false;
 
-    #if MICROPY_HW_ENABLE_USBDEV
-    tusb_init();
-    #endif
-
     #if MICROPY_PY_BLUETOOTH
     mp_bluetooth_hci_init();
     #endif
@@ -366,14 +362,20 @@ int main(void) {
     #endif
 
     // Run boot.py (or whatever else a board configures at this stage).
-    if (MICROPY_BOARD_RUN_BOOT_PY(&state) == BOARDCTRL_GOTO_SOFT_RESET_EXIT) {
-        goto soft_reset_exit;
-    }
+    int boot_res = MICROPY_BOARD_RUN_BOOT_PY(&state);
 
     // Now we initialise sub-systems that need configuration from boot.py,
     // or whose initialisation can be safely deferred until after running
     // boot.py.
 
+    #if MICROPY_HW_ENABLE_USBDEV
+    mp_usbd_init();
+    #endif
+
+    if (boot_res == BOARDCTRL_GOTO_SOFT_RESET_EXIT) {
+        goto soft_reset_exit;
+    }
+
     // At this point everything is fully configured and initialised.
 
     // Run main.py (or whatever else a board configures at this stage).

ports/rp2/main.c

@@ -38,7 +38,7 @@
 #include "shared/runtime/gchelper.h"
 #include "shared/runtime/pyexec.h"
 #include "shared/runtime/softtimer.h"
-#include "tusb.h"
+#include "shared/tinyusb/mp_usbd.h"
 #include "uart.h"
 #include "modmachine.h"
 #include "modrp2.h"
@@ -86,12 +86,9 @@ int main(int argc, char **argv) {
     #endif
     #endif
 
-    #if MICROPY_HW_ENABLE_USBDEV
-    #if MICROPY_HW_USB_CDC
+    #if MICROPY_HW_ENABLE_USBDEV && MICROPY_HW_USB_CDC
     bi_decl(bi_program_feature("USB REPL"))
     #endif
-    tusb_init();
-    #endif
 
     #if MICROPY_PY_THREAD
     bi_decl(bi_program_feature("thread support"))
@@ -181,6 +178,11 @@ int main(int argc, char **argv) {
 
         // Execute user scripts.
         int ret = pyexec_file_if_exists("boot.py");
+
+        #if MICROPY_HW_ENABLE_USBDEV
+        mp_usbd_init();
+        #endif
+
         if (ret & PYEXEC_FORCED_EXIT) {
             goto soft_reset_exit;
         }

ports/samd/main.c

@@ -33,6 +33,7 @@
 #include "shared/runtime/gchelper.h"
 #include "shared/runtime/pyexec.h"
 #include "shared/runtime/softtimer.h"
+#include "shared/tinyusb/mp_usbd.h"
 
 extern uint8_t _sstack, _estack, _sheap, _eheap;
 extern void adc_deinit_all(void);
@@ -56,6 +57,9 @@ void samd_main(void) {
 
         // Execute user scripts.
         int ret = pyexec_file_if_exists("boot.py");
+
+        mp_usbd_init();
+
         if (ret & PYEXEC_FORCED_EXIT) {
             goto soft_reset_exit;
         }

ports/samd/samd_soc.c

@@ -62,8 +62,6 @@ static void usb_init(void) {
     PORT->Group[0].PMUX[12].reg = alt << 4 | alt;
     PORT->Group[0].PINCFG[24].reg = PORT_PINCFG_PMUXEN;
     PORT->Group[0].PINCFG[25].reg = PORT_PINCFG_PMUXEN;
-
-    tusb_init();
 }
 
 // Initialize the µs counter on TC 0/1 or TC4/5

shared/tinyusb/mp_usbd.h

@@ -28,6 +28,13 @@
 #define MICROPY_INCLUDED_SHARED_TINYUSB_MP_USBD_H
 
 #include "py/obj.h"
+#include "tusb.h"
+
+static inline void mp_usbd_init(void) {
+    // Currently this is a thin wrapper around tusb_init(), however
+    // runtime USB support will require this to be extended.
+    tusb_init();
+}
 
 // Call this to explicitly run the TinyUSB device task.
 void mp_usbd_task(void);