WebUSB serial support (compile-time option, currently defaulted to OFF)

WEBUSB_README.md

@@ -0,0 +1,94 @@
+<!--
+SPDX-FileCopyrightText: 2014 MicroPython & CircuitPython contributors (https://github.com/adafruit/circuitpython/graphs/contributors)
+
+SPDX-License-Identifier: MIT
+-->
+
+# WebUSB Serial Support
+
+To date, this has only been tested on one port (esp32s2), on one board (espressif_kaluga_1).
+
+## What it does
+
+If you have ever used CircuitPython on a platform with a graphical LCD display, you have probably
+already seen multiple "consoles" in use (although the LCD console is "output only").
+
+New compile-time option CIRCUITPY_USB_VENDOR enables an additional "console" that can be used in
+parallel with the original (CDC) serial console.
+
+Web pages that support the WebUSB standard can connect to the "vendor" interface and activate
+this WebUSB serial console at any time.
+
+You can type into either console, and CircuitPython output is sent to all active consoles.
+
+One example of a web page you can use to test drive this feature can be found at:
+
+https://adafruit.github.io/Adafruit_TinyUSB_Arduino/examples/webusb-serial/index.html
+
+## How to enable
+
+Update your platform's mpconfigboard.mk file to enable and disable specific types of USB interfaces.
+
+CIRCUITPY_USB_HID = xxx
+CIRCUITPY_USB_MIDI = xxx
+CIRCUITPY_USB_VENDOR = xxx
+
+On at least some of the hardware platforms, the maximum number of USB endpoints is fixed.
+For example, on the ESP32S2, you must pick only one of the above 3 interfaces to be enabled.
+
+Original espressif_kaluga_1 mpconfigboard.mk settings:
+
+CIRCUITPY_USB_HID = 1
+CIRCUITPY_USB_MIDI = 0
+CIRCUITPY_USB_VENDOR = 0
+
+Settings to enable WebUSB instead:
+
+CIRCUITPY_USB_HID = 0
+CIRCUITPY_USB_MIDI = 0
+CIRCUITPY_USB_VENDOR = 1
+
+Notice that to enable VENDOR on ESP32-S2, we had to give up HID. There may be platforms that can have both, or even all three.
+
+## Implementation Notes
+
+CircuitPython uses the tinyusb library.
+
+The tinyusb library already has support for WebUSB serial.
+The tinyusb examples already include a "WebUSB serial" example.
+
+    Sidenote - The use of the term "vendor" instead of "WebUSB" was done to match tinyusb.
+
+Basically, this feature was ported into CircuitPython by pulling code snippets out of the
+tinyusb example, and putting them where they best belonged in the CircuitPython codebase.
+
+There was one complication:
+
+tinyusb uses C preprocessor macros to define things like USB descriptors.
+
+CircuitPython uses a Python program (tools/gen_usb_descriptor.py) to create USB descriptors (etc.)
+using "helper objects" from another repo (adafruit_usb_descriptor). This means some of the example
+code had to be adapted to the new programing model, and gen_usb_descriptor gained new command-line
+options to control the generated code.
+
+The generated files go into the "build" directory, look for autogen_usb_descriptor.c and
+genhdr/autogen_usb_descriptor.h.
+
+
+Also worth pointing out - the re-use of the CDC connect/disconnect mechanism is not actually part
+of the WebUSB standard, it's more of "common idiom". We make use of it here because we need to know
+when we should be paying attention to the WebUSB serial interface, and when we should ignore it..
+
+## Possible future work areas
+
+The current code uses the existing Python infrastructure to create the Interface descriptor, but
+simply outputs the code snippets from the original tinyusb demo code to create the WEBUSB_URL,
+BOS, and MS_OS_20 descriptors. I suppose additional work could be done to add these to the
+adafruit_usb_descriptor project, and then gen_usb_descriptor.py could be modified to make use
+of them.
+
+Program gen_usb_descriptor.py creates objects for most interface types, regardless of whether or
+not they are actually enabled. This increases the size of a generated string table. I made the
+new vendor-interface-related code not do this (because some of the ARM platforms would no longer
+build), but I did not go back and do this for the other interface types (CDC, MIDI, HID, etc.)
+Some FLASH savings are probably possible if this is done.

docs/index.rst

@@ -46,6 +46,7 @@ Full Table of Contents
    ../BUILDING
    ../CODE_OF_CONDUCT
    ../license.rst
+   ../WEBUSB_README
 
 Indices and tables
 ==================

ports/esp32s2/Makefile

@@ -164,7 +164,9 @@ LIBS += -lm
 endif
 
 # TinyUSB defines
-CFLAGS += -DCFG_TUSB_MCU=OPT_MCU_ESP32S2 -DCFG_TUSB_OS=OPT_OS_FREERTOS -DCFG_TUD_CDC_RX_BUFSIZE=1024 -DCFG_TUD_CDC_TX_BUFSIZE=1024 -DCFG_TUD_MSC_BUFSIZE=4096 -DCFG_TUD_MIDI_RX_BUFSIZE=128 -DCFG_TUD_MIDI_TX_BUFSIZE=128
+CFLAGS += -DCFG_TUSB_MCU=OPT_MCU_ESP32S2 -DCFG_TUSB_OS=OPT_OS_FREERTOS -DCFG_TUD_CDC_RX_BUFSIZE=1024 -DCFG_TUD_CDC_TX_BUFSIZE=1024
+CFLAGS += -DCFG_TUD_MSC_BUFSIZE=4096 -DCFG_TUD_MIDI_RX_BUFSIZE=128 -DCFG_TUD_MIDI_TX_BUFSIZE=128
+CFLAGS += -DCFG_TUD_VENDOR_RX_BUFSIZE=128 -DCFG_TUD_VENDOR_TX_BUFSIZE=128
 
 
 ######################################

ports/esp32s2/boards/espressif_kaluga_1/mpconfigboard.mk

@@ -14,4 +14,10 @@ CIRCUITPY_ESP_FLASH_MODE=dio
 CIRCUITPY_ESP_FLASH_FREQ=80m
 CIRCUITPY_ESP_FLASH_SIZE=4MB
 
+# We only have enough endpoints available in hardware to
+# enable ONE of these at a time.
+CIRCUITPY_USB_MIDI = 1
+CIRCUITPY_USB_HID = 0
+CIRCUITPY_USB_VENDOR = 0
+
 CIRCUITPY_MODULE=wrover

ports/esp32s2/mpconfigport.mk

@@ -29,7 +29,10 @@ CIRCUITPY_I2CPERIPHERAL = 0
 CIRCUITPY_ROTARYIO = 1
 CIRCUITPY_NVM = 1
 # We don't have enough endpoints to include MIDI.
-CIRCUITPY_USB_MIDI = 0
+CIRCUITPY_USB_MIDI ?= 0
+CIRCUITPY_USB_HID ?= 1
+# We have borrowed the VENDOR nomenclature from tinyusb. VENDOR AKA WEBUSB
+CIRCUITPY_USB_VENDOR ?= 0
 CIRCUITPY_WIFI = 1
 CIRCUITPY_WATCHDOG ?= 1
 CIRCUITPY_ESPIDF = 1

py/circuitpy_defns.mk

@@ -292,6 +292,9 @@ endif
 ifeq ($(CIRCUITPY_USB_MIDI),1)
 SRC_PATTERNS += usb_midi/%
 endif
+ifeq ($(CIRCUITPY_USB_VENDOR),1)
+SRC_PATTERNS += usb_vendor/%
+endif
 ifeq ($(CIRCUITPY_USTACK),1)
 SRC_PATTERNS += ustack/%
 endif

py/circuitpy_mpconfig.mk

@@ -288,6 +288,12 @@ CFLAGS += -DCIRCUITPY_USB_HID=$(CIRCUITPY_USB_HID)
 CIRCUITPY_USB_MIDI ?= 1
 CFLAGS += -DCIRCUITPY_USB_MIDI=$(CIRCUITPY_USB_MIDI)
 
+# Defaulting this to OFF initially because it has only been tested on a
+# limited number of platforms, and the other platforms do not have this
+# setting in their mpconfigport.mk and/or mpconfigboard.mk files yet.
+CIRCUITPY_USB_VENDOR ?= 0
+CFLAGS += -DCIRCUITPY_USB_VENDOR=$(CIRCUITPY_USB_VENDOR)
+
 CIRCUITPY_PEW ?= 0
 CFLAGS += -DCIRCUITPY_PEW=$(CIRCUITPY_PEW)
 

supervisor/shared/serial.c

@@ -47,6 +47,10 @@ busio_uart_obj_t debug_uart;
 byte buf_array[64];
 #endif
 
+#if CIRCUITPY_USB_VENDOR
+bool tud_vendor_connected(void);
+#endif
+
 void serial_early_init(void) {
 #if defined(DEBUG_UART_TX) && defined(DEBUG_UART_RX)
     debug_uart.base.type = &busio_uart_type;
@@ -66,6 +70,12 @@ void serial_init(void) {
 }
 
 bool serial_connected(void) {
+#if CIRCUITPY_USB_VENDOR
+    if (tud_vendor_connected()) {
+        return true;
+    }
+#endif
+
 #if defined(DEBUG_UART_TX) && defined(DEBUG_UART_RX)
     return true;
 #else
@@ -74,6 +84,14 @@ bool serial_connected(void) {
 }
 
 char serial_read(void) {
+#if CIRCUITPY_USB_VENDOR
+    if (tud_vendor_connected() && tud_vendor_available() > 0) {
+        char tiny_buffer;
+        tud_vendor_read(&tiny_buffer, 1);
+        return tiny_buffer;
+    }
+#endif
+
 #if defined(DEBUG_UART_TX) && defined(DEBUG_UART_RX)
     if (tud_cdc_connected() && tud_cdc_available() > 0) {
         return (char) tud_cdc_read_char();
@@ -88,6 +106,12 @@ char serial_read(void) {
 }
 
 bool serial_bytes_available(void) {
+#if CIRCUITPY_USB_VENDOR
+    if (tud_vendor_connected() && tud_vendor_available() > 0) {
+        return true;
+    }
+#endif
+
 #if defined(DEBUG_UART_TX) && defined(DEBUG_UART_RX)
     return common_hal_busio_uart_rx_characters_available(&debug_uart) || (tud_cdc_available() > 0);
 #else
@@ -104,6 +128,12 @@ void serial_write_substring(const char* text, uint32_t length) {
     common_hal_terminalio_terminal_write(&supervisor_terminal, (const uint8_t*) text, length, &errcode);
 #endif
 
+#if CIRCUITPY_USB_VENDOR
+    if (tud_vendor_connected()) {
+        tud_vendor_write(text, length);
+    }
+#endif
+
     uint32_t count = 0;
     while (count < length && tud_cdc_connected()) {
         count += tud_cdc_write(text + count, length - count);

supervisor/shared/usb/tusb_config.h

@@ -68,6 +68,7 @@
 #define CFG_TUD_MSC                 1
 #define CFG_TUD_HID                 CIRCUITPY_USB_HID
 #define CFG_TUD_MIDI                CIRCUITPY_USB_MIDI
+#define CFG_TUD_VENDOR              CIRCUITPY_USB_VENDOR
 #define CFG_TUD_CUSTOM_CLASS        0
 
 /*------------------------------------------------------------------*/

supervisor/shared/usb/usb.c

@@ -37,6 +37,19 @@
 
 #include "tusb.h"
 
+#if CIRCUITPY_USB_VENDOR
+#include "genhdr/autogen_usb_descriptor.h"
+
+// The WebUSB support being conditionally added to this file is based on the
+// tinyusb demo examples/device/webusb_serial.
+
+extern const tusb_desc_webusb_url_t desc_webusb_url;
+
+static bool web_serial_connected = false;
+#endif
+
+
+
 // Serial number as hex characters. This writes directly to the USB
 // descriptor.
 extern uint16_t usb_serial_number[1 + COMMON_HAL_MCU_PROCESSOR_UID_LENGTH * 2];
@@ -145,6 +158,62 @@ void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts) {
     }
 }
 
+#if CIRCUITPY_USB_VENDOR
+//--------------------------------------------------------------------+
+// WebUSB use vendor class
+//--------------------------------------------------------------------+
+
+bool tud_vendor_connected(void)
+{
+  return web_serial_connected;
+}
+
+// Invoked when a control transfer occurred on an interface of this class
+// Driver response accordingly to the request and the transfer stage (setup/data/ack)
+// return false to stall control endpoint (e.g unsupported request)
+bool tud_vendor_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb_control_request_t const * request)
+{
+  // nothing to with DATA & ACK stage
+  if (stage != CONTROL_STAGE_SETUP ) return true;
+
+  switch (request->bRequest)
+  {
+    case VENDOR_REQUEST_WEBUSB:
+      // match vendor request in BOS descriptor
+      // Get landing page url
+      return tud_control_xfer(rhport, request, (void*) &desc_webusb_url, desc_webusb_url.bLength);
+
+    case VENDOR_REQUEST_MICROSOFT:
+      if ( request->wIndex == 7 )
+      {
+        // Get Microsoft OS 2.0 compatible descriptor
+        uint16_t total_len;
+        memcpy(&total_len, desc_ms_os_20+8, 2);
+
+        return tud_control_xfer(rhport, request, (void*) desc_ms_os_20, total_len);
+      } else
+      {
+        return false;
+      }
+
+    case 0x22:
+      // Webserial simulate the CDC_REQUEST_SET_CONTROL_LINE_STATE (0x22) to
+      // connect and disconnect.
+      web_serial_connected = (request->wValue != 0);
+
+      // response with status OK
+      return tud_control_status(rhport, request);
+
+    default:
+      // stall unknown request
+      return false;
+  }
+
+  return true;
+}
+#endif CIRCUITPY_USB_VENDOR
+
+
 #if MICROPY_KBD_EXCEPTION
 
 /**

supervisor/supervisor.mk

@@ -102,6 +102,11 @@ else
 			shared-module/usb_midi/PortOut.c
 	endif
 
+	ifeq ($(CIRCUITPY_USB_VENDOR), 1)
+		SRC_SUPERVISOR += \
+			lib/tinyusb/src/class/vendor/vendor_device.c
+	endif
+
 	CFLAGS += -DUSB_AVAILABLE
 endif
 
@@ -119,13 +124,22 @@ ifndef USB_INTERFACE_NAME
 USB_INTERFACE_NAME = "CircuitPython"
 endif
 
+# In the following URL, don't include the https:// prefix.
+# It gets added automatically.
+ifndef USB_WEBUSB_URL
+USB_WEBUSB_URL = "circuitpython.org"
+endif
+
 USB_DEVICES_COMPUTED := CDC,MSC
 ifeq ($(CIRCUITPY_USB_MIDI),1)
 USB_DEVICES_COMPUTED := $(USB_DEVICES_COMPUTED),AUDIO
 endif
 ifeq ($(CIRCUITPY_USB_HID),1)
 USB_DEVICES_COMPUTED := $(USB_DEVICES_COMPUTED),HID
 endif
+ifeq ($(CIRCUITPY_USB_VENDOR),1)
+USB_DEVICES_COMPUTED := $(USB_DEVICES_COMPUTED),VENDOR
+endif
 USB_DEVICES ?= "$(USB_DEVICES_COMPUTED)"
 
 ifndef USB_HID_DEVICES
@@ -198,6 +212,12 @@ USB_DESCRIPTOR_ARGS = \
 	--output_c_file $(BUILD)/autogen_usb_descriptor.c\
 	--output_h_file $(BUILD)/genhdr/autogen_usb_descriptor.h
 
+ifeq ($(CIRCUITPY_USB_VENDOR), 1)
+USB_DESCRIPTOR_ARGS += \
+        --vendor_ep_num_out 0 --vendor_ep_num_in 0 \
+        --webusb_url $(USB_WEBUSB_URL)
+endif
+
 ifeq ($(USB_RENUMBER_ENDPOINTS), 0)
 USB_DESCRIPTOR_ARGS += --no-renumber_endpoints
 endif