lpc176x: Initial support for serial over usb

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/generic/usb_cdc.h

@@ -0,0 +1,35 @@
+#ifndef __GENERIC_USB_CDC_H
+#define __GENERIC_USB_CDC_H
+
+#include <stdint.h> // uint_fast8_t
+
+enum {
+    USB_CDC_EP0_SIZE = 16,
+
+    // XXX - endpoint ids may need to changed per-board
+    USB_CDC_EP_ACM = 1,
+    USB_CDC_EP_ACM_SIZE = 8,
+
+    USB_CDC_EP_BULK_OUT = 2,
+    USB_CDC_EP_BULK_OUT_SIZE = 64,
+
+    USB_CDC_EP_BULK_IN = 5,
+    USB_CDC_EP_BULK_IN_SIZE = 64,
+};
+
+// callbacks provided by board specific code
+int_fast8_t usb_read_bulk_out(void *data, uint_fast8_t max_len);
+int_fast8_t usb_send_bulk_in(void *data, uint_fast8_t len);
+int_fast8_t usb_read_setup(void *data, uint_fast8_t max_len);
+int_fast8_t usb_send_setup(const void *data, uint_fast8_t len);
+void usb_send_pgm_setup(void *data, uint_fast8_t len);
+void usb_set_stall(void);
+void usb_set_address(uint_fast8_t addr);
+void usb_set_configure(void);
+
+// usb_cdc.c
+void usb_notify_bulk_in(void);
+void usb_notify_bulk_out(void);
+void usb_notify_setup(void);
+
+#endif // usb_cdc.h

src/generic/usbstd.h

@@ -0,0 +1,121 @@
+// Standard definitions for USB commands and data structures
+#ifndef __GENERIC_USBSTD_H
+#define __GENERIC_USBSTD_H
+
+#include <stdint.h> // uint8_t
+#include "compiler.h" // PACKED
+
+#define USB_DIR_OUT                     0               /* to device */
+#define USB_DIR_IN                      0x80            /* to host */
+
+#define USB_REQ_GET_STATUS              0x00
+#define USB_REQ_CLEAR_FEATURE           0x01
+#define USB_REQ_SET_FEATURE             0x03
+#define USB_REQ_SET_ADDRESS             0x05
+#define USB_REQ_GET_DESCRIPTOR          0x06
+#define USB_REQ_SET_DESCRIPTOR          0x07
+#define USB_REQ_GET_CONFIGURATION       0x08
+#define USB_REQ_SET_CONFIGURATION       0x09
+#define USB_REQ_GET_INTERFACE           0x0A
+#define USB_REQ_SET_INTERFACE           0x0B
+#define USB_REQ_SYNCH_FRAME             0x0C
+
+struct usb_ctrlrequest {
+    uint8_t bRequestType;
+    uint8_t bRequest;
+    uint16_t wValue;
+    uint16_t wIndex;
+    uint16_t wLength;
+} PACKED;
+
+#define USB_DT_DEVICE                   0x01
+#define USB_DT_CONFIG                   0x02
+#define USB_DT_STRING                   0x03
+#define USB_DT_INTERFACE                0x04
+#define USB_DT_ENDPOINT                 0x05
+#define USB_DT_DEVICE_QUALIFIER         0x06
+#define USB_DT_OTHER_SPEED_CONFIG       0x07
+#define USB_DT_ENDPOINT_COMPANION       0x30
+
+struct usb_device_descriptor {
+    uint8_t  bLength;
+    uint8_t  bDescriptorType;
+
+    uint16_t bcdUSB;
+    uint8_t  bDeviceClass;
+    uint8_t  bDeviceSubClass;
+    uint8_t  bDeviceProtocol;
+    uint8_t  bMaxPacketSize0;
+    uint16_t idVendor;
+    uint16_t idProduct;
+    uint16_t bcdDevice;
+    uint8_t  iManufacturer;
+    uint8_t  iProduct;
+    uint8_t  iSerialNumber;
+    uint8_t  bNumConfigurations;
+} PACKED;
+
+#define USB_CLASS_PER_INTERFACE         0       /* for DeviceClass */
+#define USB_CLASS_AUDIO                 1
+#define USB_CLASS_COMM                  2
+#define USB_CLASS_HID                   3
+#define USB_CLASS_PHYSICAL              5
+#define USB_CLASS_STILL_IMAGE           6
+#define USB_CLASS_PRINTER               7
+#define USB_CLASS_MASS_STORAGE          8
+#define USB_CLASS_HUB                   9
+
+struct usb_config_descriptor {
+    uint8_t  bLength;
+    uint8_t  bDescriptorType;
+
+    uint16_t wTotalLength;
+    uint8_t  bNumInterfaces;
+    uint8_t  bConfigurationValue;
+    uint8_t  iConfiguration;
+    uint8_t  bmAttributes;
+    uint8_t  bMaxPower;
+} PACKED;
+
+struct usb_interface_descriptor {
+    uint8_t  bLength;
+    uint8_t  bDescriptorType;
+
+    uint8_t  bInterfaceNumber;
+    uint8_t  bAlternateSetting;
+    uint8_t  bNumEndpoints;
+    uint8_t  bInterfaceClass;
+    uint8_t  bInterfaceSubClass;
+    uint8_t  bInterfaceProtocol;
+    uint8_t  iInterface;
+} PACKED;
+
+struct usb_endpoint_descriptor {
+    uint8_t  bLength;
+    uint8_t  bDescriptorType;
+
+    uint8_t  bEndpointAddress;
+    uint8_t  bmAttributes;
+    uint16_t wMaxPacketSize;
+    uint8_t  bInterval;
+} PACKED;
+
+#define USB_ENDPOINT_NUMBER_MASK        0x0f    /* in bEndpointAddress */
+#define USB_ENDPOINT_DIR_MASK           0x80
+
+#define USB_ENDPOINT_XFERTYPE_MASK      0x03    /* in bmAttributes */
+#define USB_ENDPOINT_XFER_CONTROL       0
+#define USB_ENDPOINT_XFER_ISOC          1
+#define USB_ENDPOINT_XFER_BULK          2
+#define USB_ENDPOINT_XFER_INT           3
+#define USB_ENDPOINT_MAX_ADJUSTABLE     0x80
+
+struct usb_string_descriptor {
+    uint8_t bLength;
+    uint8_t bDescriptorType;
+    uint16_t data[];
+} PACKED;
+
+#define USB_LANGID_ENGLISH_US 0x0409
+
+#endif // usbstd.h

src/generic/usbstd_cdc.h

@@ -0,0 +1,49 @@
+// Standard definitions for USB CDC devices
+#ifndef __GENERIC_USBSTD_CDC_H
+#define __GENERIC_USBSTD_CDC_H
+
+#define USB_CDC_SUBCLASS_ACM 0x02
+
+#define USB_CDC_ACM_PROTO_AT_V25TER 1
+
+struct usb_cdc_header_descriptor {
+    uint8_t bLength;
+    uint8_t bDescriptorType;
+    uint8_t bDescriptorSubType;
+    uint16_t bcdCDC;
+} PACKED;
+
+#define USB_CDC_HEADER_TYPE 0x00
+#define USB_CDC_ACM_TYPE 0x02
+#define USB_CDC_UNION_TYPE 0x06
+
+#define USB_CDC_CS_INTERFACE 0x24
+#define USB_CDC_CS_ENDPOINT 0x25
+
+struct usb_cdc_acm_descriptor {
+    uint8_t bLength;
+    uint8_t bDescriptorType;
+    uint8_t bDescriptorSubType;
+    uint8_t bmCapabilities;
+} PACKED;
+
+struct usb_cdc_union_descriptor {
+    uint8_t bLength;
+    uint8_t bDescriptorType;
+    uint8_t bDescriptorSubType;
+    uint8_t bMasterInterface0;
+    uint8_t bSlaveInterface0;
+} PACKED;
+
+#define USB_CDC_REQ_SET_LINE_CODING 0x20
+#define USB_CDC_REQ_GET_LINE_CODING 0x21
+#define USB_CDC_REQ_SET_CONTROL_LINE_STATE 0x22
+
+struct usb_cdc_line_coding {
+    uint32_t dwDTERate;
+    uint8_t bCharFormat;
+    uint8_t bParityType;
+    uint8_t bDataBits;
+} PACKED;
+
+#endif // usbstd_cdc.h

src/lpc176x/Kconfig

@@ -25,7 +25,11 @@ config CLOCK_FREQ
     default 25000000 if MACH_LPC1768 # 100000000 / 4
     default 30000000 if MACH_LPC1769 # 120000000 / 4
 
+config USBSERIAL
+    bool "Use USB for communication (instead of serial)"
+    default y
 config SERIAL
+    depends on !USBSERIAL
     bool
     default y
 config SERIAL_BAUD

src/lpc176x/Makefile

@@ -17,6 +17,7 @@ src-y += lpc176x/main.c lpc176x/timer.c lpc176x/gpio.c
 src-y += generic/crc16_ccitt.c generic/alloc.c
 src-y += generic/armcm_irq.c generic/timer_irq.c
 src-y += ../lib/lpc176x/device/system_LPC17xx.c
+src-$(CONFIG_USBSERIAL) += lpc176x/usbserial.c generic/usb_cdc.c
 src-$(CONFIG_SERIAL) += lpc176x/serial.c generic/serial_irq.c
 
 # Add the TOOLCHAIN_GCC_ARM files to the build

src/lpc176x/timer.c

@@ -38,7 +38,7 @@ timer_init(void)
     // Disable timer
     LPC_TIM0->TCR = 0x02;
     // Enable interrupts
-    NVIC_SetPriority(TIMER0_IRQn, 1);
+    NVIC_SetPriority(TIMER0_IRQn, 2);
     NVIC_EnableIRQ(TIMER0_IRQn);
     LPC_TIM0->MCR = 0x01;
     // Clear counter value