bluepill: add usbcdc example

pio/bluepill/usbcdc/include/README

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+
+This directory is intended for project header files.
+
+A header file is a file containing C declarations and macro definitions
+to be shared between several project source files. You request the use of a
+header file in your project source file (C, C++, etc) located in `src` folder
+by including it, with the C preprocessing directive `#include'.
+
+```src/main.c
+
+#include "header.h"
+
+int main (void)
+{
+ ...
+}
+```
+
+Including a header file produces the same results as copying the header file
+into each source file that needs it. Such copying would be time-consuming
+and error-prone. With a header file, the related declarations appear
+in only one place. If they need to be changed, they can be changed in one
+place, and programs that include the header file will automatically use the
+new version when next recompiled. The header file eliminates the labor of
+finding and changing all the copies as well as the risk that a failure to
+find one copy will result in inconsistencies within a program.
+
+In C, the usual convention is to give header files names that end with `.h'.
+It is most portable to use only letters, digits, dashes, and underscores in
+header file names, and at most one dot.
+
+Read more about using header files in official GCC documentation:
+
+* Include Syntax
+* Include Operation
+* Once-Only Headers
+* Computed Includes
+
+https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html

pio/bluepill/usbcdc/lib/README

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+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into executable file.
+
+The source code of each library should be placed in a an own separate directory
+("lib/your_library_name/[here are source files]").
+
+For example, see a structure of the following two libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional, custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+and a contents of `src/main.c`:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+PlatformIO Library Dependency Finder will find automatically dependent
+libraries scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html

pio/bluepill/usbcdc/platformio.ini

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+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[env:bluepill_f103c8]
+platform = ststm32
+board = bluepill_f103c8
+framework = libopencm3

pio/bluepill/usbcdc/src/main.c

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+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2010 Gareth McMullin <gareth@blacksphere.co.nz>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/gpio.h>
+#include <libopencm3/usb/usbd.h>
+#include <libopencm3/usb/cdc.h>
+
+
+static const struct usb_device_descriptor dev = {
+	.bLength = USB_DT_DEVICE_SIZE,
+	.bDescriptorType = USB_DT_DEVICE,
+	.bcdUSB = 0x0200,
+	.bDeviceClass = USB_CLASS_CDC,
+	.bDeviceSubClass = 0,
+	.bDeviceProtocol = 0,
+	.bMaxPacketSize0 = 64,
+	.idVendor = 0x0483,
+	.idProduct = 0x5740,
+	.bcdDevice = 0x0200,
+	.iManufacturer = 1,
+	.iProduct = 2,
+	.iSerialNumber = 3,
+	.bNumConfigurations = 1,
+};
+
+
+/*
+ * This notification endpoint isn't implemented. According to CDC spec its
+ * optional, but its absence causes a NULL pointer dereference in Linux
+ * cdc_acm driver.
+ */
+static const struct usb_endpoint_descriptor comm_endp[] = {{
+	.bLength = USB_DT_ENDPOINT_SIZE,
+		.bDescriptorType = USB_DT_ENDPOINT,
+		.bEndpointAddress = 0x83,
+		.bmAttributes = USB_ENDPOINT_ATTR_INTERRUPT,
+		.wMaxPacketSize = 16,
+		.bInterval = 255,
+}};
+
+
+static const struct usb_endpoint_descriptor data_endp[] = {{
+	.bLength = USB_DT_ENDPOINT_SIZE,
+		.bDescriptorType = USB_DT_ENDPOINT,
+		.bEndpointAddress = 0x01,
+		.bmAttributes = USB_ENDPOINT_ATTR_BULK,
+		.wMaxPacketSize = 64,
+		.bInterval = 1,
+}, {
+	.bLength = USB_DT_ENDPOINT_SIZE,
+		.bDescriptorType = USB_DT_ENDPOINT,
+		.bEndpointAddress = 0x82,
+		.bmAttributes = USB_ENDPOINT_ATTR_BULK,
+		.wMaxPacketSize = 64,
+		.bInterval = 1,
+}};
+
+
+static const struct {
+	struct usb_cdc_header_descriptor header;
+	struct usb_cdc_call_management_descriptor call_mgmt;
+	struct usb_cdc_acm_descriptor acm;
+	struct usb_cdc_union_descriptor cdc_union;
+} __attribute__((packed)) cdcacm_functional_descriptors = {
+	.header = {
+		.bFunctionLength = sizeof(struct usb_cdc_header_descriptor),
+		.bDescriptorType = CS_INTERFACE,
+		.bDescriptorSubtype = USB_CDC_TYPE_HEADER,
+		.bcdCDC = 0x0110,
+	},
+	.call_mgmt = {
+		.bFunctionLength =
+			sizeof(struct usb_cdc_call_management_descriptor),
+		.bDescriptorType = CS_INTERFACE,
+		.bDescriptorSubtype = USB_CDC_TYPE_CALL_MANAGEMENT,
+		.bmCapabilities = 0,
+		.bDataInterface = 1,
+	},
+	.acm = {
+		.bFunctionLength = sizeof(struct usb_cdc_acm_descriptor),
+		.bDescriptorType = CS_INTERFACE,
+		.bDescriptorSubtype = USB_CDC_TYPE_ACM,
+		.bmCapabilities = 0,
+	},
+	.cdc_union = {
+		.bFunctionLength = sizeof(struct usb_cdc_union_descriptor),
+		.bDescriptorType = CS_INTERFACE,
+		.bDescriptorSubtype = USB_CDC_TYPE_UNION,
+		.bControlInterface = 0,
+		.bSubordinateInterface0 = 1,
+	},
+};
+
+
+static const struct usb_interface_descriptor comm_iface[] = {{
+	.bLength = USB_DT_INTERFACE_SIZE,
+		.bDescriptorType = USB_DT_INTERFACE,
+		.bInterfaceNumber = 0,
+		.bAlternateSetting = 0,
+		.bNumEndpoints = 1,
+		.bInterfaceClass = USB_CLASS_CDC,
+		.bInterfaceSubClass = USB_CDC_SUBCLASS_ACM,
+		.bInterfaceProtocol = USB_CDC_PROTOCOL_AT,
+		.iInterface = 0,
+
+		.endpoint = comm_endp,
+
+		.extra = &cdcacm_functional_descriptors,
+		.extralen = sizeof(cdcacm_functional_descriptors),
+}};
+
+
+static const struct usb_interface_descriptor data_iface[] = {{
+	.bLength = USB_DT_INTERFACE_SIZE,
+		.bDescriptorType = USB_DT_INTERFACE,
+		.bInterfaceNumber = 1,
+		.bAlternateSetting = 0,
+		.bNumEndpoints = 2,
+		.bInterfaceClass = USB_CLASS_DATA,
+		.bInterfaceSubClass = 0,
+		.bInterfaceProtocol = 0,
+		.iInterface = 0,
+
+		.endpoint = data_endp,
+}};
+
+
+static const struct usb_interface ifaces[] = {{
+	.num_altsetting = 1,
+		.altsetting = comm_iface,
+}, {
+	.num_altsetting = 1,
+		.altsetting = data_iface,
+}};
+
+
+static const struct usb_config_descriptor config = {
+	.bLength = USB_DT_CONFIGURATION_SIZE,
+	.bDescriptorType = USB_DT_CONFIGURATION,
+	.wTotalLength = 0,
+	.bNumInterfaces = 2,
+	.bConfigurationValue = 1,
+	.iConfiguration = 0,
+	.bmAttributes = 0x80,
+	.bMaxPower = 0x32,
+
+	.interface = ifaces,
+};
+
+
+static const char *usb_strings[] = {
+	"Black Sphere Technologies",
+	"CDC-ACM Demo",
+	"DEMO",
+};
+
+
+/* Buffer to be used for control requests. */
+uint8_t usbd_control_buffer[128];
+
+
+static enum usbd_request_return_codes
+cdcacm_control_request(usbd_device *usbd_dev, struct usb_setup_data *req, uint8_t **buf,
+		       uint16_t *len, void (**complete)(usbd_device *usbd_dev, struct usb_setup_data *req))
+{
+	(void)complete;
+	(void)buf;
+	(void)usbd_dev;
+
+	switch (req->bRequest) {
+		case USB_CDC_REQ_SET_CONTROL_LINE_STATE: {
+								 /*
+								  * This Linux cdc_acm driver requires this to be implemented
+								  * even though it's optional in the CDC spec, and we don't
+								  * advertise it in the ACM functional descriptor.
+								  */
+								 char local_buf[10];
+								 struct usb_cdc_notification *notif = (void *)local_buf;
+
+								 /* We echo signals back to host as notification. */
+								 notif->bmRequestType = 0xA1;
+								 notif->bNotification = USB_CDC_NOTIFY_SERIAL_STATE;
+								 notif->wValue = 0;
+								 notif->wIndex = 0;
+								 notif->wLength = 2;
+								 local_buf[8] = req->wValue & 3;
+								 local_buf[9] = 0;
+								 // usbd_ep_write_packet(0x83, buf, 10);
+								 return USBD_REQ_HANDLED;
+							 }
+		case USB_CDC_REQ_SET_LINE_CODING:
+							 if (*len < sizeof(struct usb_cdc_line_coding))
+								 return USBD_REQ_NOTSUPP;
+							 return USBD_REQ_HANDLED;
+	}
+	return USBD_REQ_NOTSUPP;
+}
+
+
+static void
+cdcacm_data_rx_cb(usbd_device *usbd_dev, uint8_t ep)
+{
+	(void)ep;
+	(void)usbd_dev;
+
+	char buf[64];
+	int len = usbd_ep_read_packet(usbd_dev, 0x01, buf, 64);
+
+	if (len) {
+		usbd_ep_write_packet(usbd_dev, 0x82, buf, len);
+		buf[len] = 0;
+	}
+}
+
+
+static void
+cdcacm_set_config(usbd_device *usbd_dev, uint16_t wValue)
+{
+	(void)wValue;
+	(void)usbd_dev;
+
+	usbd_ep_setup(usbd_dev, 0x01, USB_ENDPOINT_ATTR_BULK, 64, cdcacm_data_rx_cb);
+	usbd_ep_setup(usbd_dev, 0x82, USB_ENDPOINT_ATTR_BULK, 64, NULL);
+	usbd_ep_setup(usbd_dev, 0x83, USB_ENDPOINT_ATTR_INTERRUPT, 16, NULL);
+
+	usbd_register_control_callback(
+			usbd_dev,
+			USB_REQ_TYPE_CLASS | USB_REQ_TYPE_INTERFACE,
+			USB_REQ_TYPE_TYPE | USB_REQ_TYPE_RECIPIENT,
+			cdcacm_control_request);
+}
+
+
+int
+main(void)
+{
+	int i;
+
+	usbd_device *usbd_dev;
+
+	rcc_clock_setup_in_hsi_out_48mhz();
+
+	rcc_periph_clock_enable(RCC_GPIOC);
+
+	gpio_set(GPIOC, GPIO11);
+	gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_2_MHZ,
+			GPIO_CNF_OUTPUT_PUSHPULL, GPIO11);
+
+	usbd_dev = usbd_init(&st_usbfs_v1_usb_driver, &dev, &config, usb_strings, 3, usbd_control_buffer, sizeof(usbd_control_buffer));
+	usbd_register_set_config_callback(usbd_dev, cdcacm_set_config);
+
+	for (i = 0; i < 0x800000; i++)
+		__asm__("nop");
+	gpio_clear(GPIOC, GPIO11);
+
+	while (1)
+		usbd_poll(usbd_dev);
+}
+

pio/bluepill/usbcdc/test/README

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+
+This directory is intended for PIO Unit Testing and project tests.
+
+Unit Testing is a software testing method by which individual units of
+source code, sets of one or more MCU program modules together with associated
+control data, usage procedures, and operating procedures, are tested to
+determine whether they are fit for use. Unit testing finds problems early
+in the development cycle.
+
+More information about PIO Unit Testing:
+- https://docs.platformio.org/page/plus/unit-testing.html