esp32: Add automatic bootloader handling for S2 and S3.

Enables support for the ESP standard DTR/RTS based reboot to bootloader.

Switches from OTG to Serial/Jtag mode to workaround issue discussed
in: https://github.com/espressif/arduino-esp32/issues/6762

Signed-off-by: Andrew Leech <andrew@alelec.net>

ports/esp32/boards/ESP32_GENERIC_S3/sdkconfig.board

@@ -1,6 +1,5 @@
 CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_ESPTOOLPY_AFTER_NORESET=y
 
 CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
 CONFIG_ESPTOOLPY_FLASHSIZE_8MB=y

ports/esp32/boards/UM_FEATHERS2/sdkconfig.board

@@ -1,6 +1,5 @@
 CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_ESPTOOLPY_AFTER_NORESET=y
 
 CONFIG_SPIRAM_MEMTEST=
 

ports/esp32/boards/UM_FEATHERS2NEO/sdkconfig.board

@@ -1,6 +1,5 @@
 CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_ESPTOOLPY_AFTER_NORESET=y
 
 # LWIP
 CONFIG_LWIP_LOCAL_HOSTNAME="UMFeatherS2Neo"

ports/esp32/boards/UM_FEATHERS3/sdkconfig.board

@@ -1,6 +1,5 @@
 CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_ESPTOOLPY_AFTER_NORESET=y
 
 CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
 CONFIG_ESPTOOLPY_FLASHSIZE_8MB=

ports/esp32/boards/UM_NANOS3/sdkconfig.board

@@ -1,6 +1,5 @@
 CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_ESPTOOLPY_AFTER_NORESET=y
 
 CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
 CONFIG_ESPTOOLPY_FLASHSIZE_8MB=y

ports/esp32/boards/UM_PROS3/sdkconfig.board

@@ -1,6 +1,5 @@
 CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_ESPTOOLPY_AFTER_NORESET=y
 
 CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
 CONFIG_ESPTOOLPY_FLASHSIZE_8MB=

ports/esp32/boards/UM_TINYS2/sdkconfig.board

@@ -1,6 +1,5 @@
 CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_ESPTOOLPY_AFTER_NORESET=y
 
 # LWIP
 CONFIG_LWIP_LOCAL_HOSTNAME="UMTinyS2"

ports/esp32/boards/UM_TINYS3/sdkconfig.board

@@ -1,6 +1,5 @@
 CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_ESPTOOLPY_AFTER_NORESET=y
 
 CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
 CONFIG_ESPTOOLPY_FLASHSIZE_8MB=y

ports/esp32/boards/UM_TINYWATCHS3/sdkconfig.board

@@ -1,6 +1,5 @@
 CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_ESPTOOLPY_AFTER_NORESET=y
 
 CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
 CONFIG_ESPTOOLPY_FLASHSIZE_8MB=y

ports/esp32/modmachine.c

@@ -222,7 +222,19 @@ static mp_int_t mp_machine_reset_cause(void) {
 
 #if MICROPY_ESP32_USE_BOOTLOADER_RTC
 #include "soc/rtc_cntl_reg.h"
+#include "usb.h"
+#if CONFIG_IDF_TARGET_ESP32S3
+#include "esp32s3/rom/usb/usb_dc.h"
+#include "esp32s3/rom/usb/usb_persist.h"
+#include "esp32s3/rom/usb/chip_usb_dw_wrapper.h"
+#endif
+
 NORETURN static void machine_bootloader_rtc(void) {
+    #if CONFIG_IDF_TARGET_ESP32S3
+    usb_usj_mode();
+    usb_dc_prepare_persist();
+    chip_usb_set_persist_flags(USBDC_BOOT_DFU);
+    #endif
     REG_WRITE(RTC_CNTL_OPTION1_REG, RTC_CNTL_FORCE_DOWNLOAD_BOOT);
     esp_restart();
 }

ports/esp32/mpconfigport.h

@@ -199,7 +199,8 @@
 #endif
 
 #if MICROPY_HW_ENABLE_USBDEV
-#define MICROPY_SCHEDULER_STATIC_NODES      (1)
+#define MICROPY_SCHEDULER_STATIC_NODES        (1)
+#define MICROPY_HW_USB_CDC_DTR_RTS_BOOTLOADER (1)
 
 #ifndef MICROPY_HW_USB_VID
 #define USB_ESPRESSIF_VID 0x303A

ports/esp32/usb.c

@@ -57,6 +57,18 @@ void usb_init(void) {
 
 }
 
+#if CONFIG_IDF_TARGET_ESP32S3
+void usb_usj_mode(void) {
+    // Switch the USB PHY back to Serial/Jtag mode, disabling OTG support
+    // This should be run before jumping to bootloader.
+    usb_del_phy(phy_hdl);
+    usb_phy_config_t phy_conf = {
+        .controller = USB_PHY_CTRL_SERIAL_JTAG,
+    };
+    usb_new_phy(&phy_conf, &phy_hdl);
+}
+#endif
+
 void mp_usbd_port_get_serial_number(char *serial_buf) {
     // use factory default MAC as serial ID
     uint8_t mac[8];

ports/esp32/usb.h

@@ -29,5 +29,6 @@
 #define MICROPY_HW_USB_CDC_TX_TIMEOUT_MS (500)
 
 void usb_init(void);
+void usb_usj_mode(void);
 
 #endif // MICROPY_INCLUDED_ESP32_USB_H

shared/tinyusb/mp_usbd_cdc.c

@@ -138,9 +138,12 @@ void tud_sof_cb(uint32_t frame_count) {
 
 #endif
 
-#if MICROPY_HW_ENABLE_USBDEV && (MICROPY_HW_USB_CDC_1200BPS_TOUCH || MICROPY_HW_USB_CDC)
+#if MICROPY_HW_ENABLE_USBDEV && ( \
+    MICROPY_HW_USB_CDC_1200BPS_TOUCH || \
+    MICROPY_HW_USB_CDC || \
+    MICROPY_HW_USB_CDC_DTR_RTS_BOOTLOADER)
 
-#if MICROPY_HW_USB_CDC_1200BPS_TOUCH
+#if MICROPY_HW_USB_CDC_1200BPS_TOUCH || MICROPY_HW_USB_CDC_DTR_RTS_BOOTLOADER
 static mp_sched_node_t mp_bootloader_sched_node;
 
 static void usbd_cdc_run_bootloader_task(mp_sched_node_t *node) {
@@ -149,6 +152,13 @@ static void usbd_cdc_run_bootloader_task(mp_sched_node_t *node) {
 }
 #endif
 
+#if MICROPY_HW_USB_CDC_DTR_RTS_BOOTLOADER
+static struct {
+    bool dtr : 1;
+    bool rts : 1;
+} prev_line_state = {0};
+#endif
+
 void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts) {
     #if MICROPY_HW_USB_CDC && !MICROPY_EXCLUDE_SHARED_TINYUSB_USBD_CDC
     if (dtr) {
@@ -159,6 +169,15 @@ void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts) {
         tud_sof_cb_enable(true);
     }
     #endif
+    #if MICROPY_HW_USB_CDC_DTR_RTS_BOOTLOADER
+    if (dtr && !rts) {
+        if (prev_line_state.rts && !prev_line_state.dtr) {
+            mp_sched_schedule_node(&mp_bootloader_sched_node, usbd_cdc_run_bootloader_task);
+        }
+    }
+    prev_line_state.rts = rts;
+    prev_line_state.dtr = dtr;
+    #endif
     #if MICROPY_HW_USB_CDC_1200BPS_TOUCH
     if (dtr == false && rts == false) {
         // Device is disconnected.

shared/tinyusb/mp_usbd_cdc.h

@@ -31,6 +31,12 @@
 #define MICROPY_HW_USB_CDC_TX_TIMEOUT (500)
 #endif
 
+// This is typically only enabled on esp32
+// parts which have an internal usb peripheral.
+#ifndef MICROPY_HW_USB_CDC_DTR_RTS_BOOTLOADER
+#define MICROPY_HW_USB_CDC_DTR_RTS_BOOTLOADER (0)
+#endif
+
 uintptr_t mp_usbd_cdc_poll_interfaces(uintptr_t poll_flags);
 void tud_cdc_rx_cb(uint8_t itf);
 mp_uint_t mp_usbd_cdc_tx_strn(const char *str, mp_uint_t len);