usb_cdc: Add support for detecting a USB level Arduino bootloader request

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

src/avr/usbserial.c

@@ -178,6 +178,11 @@ usb_set_configure(void)
     UEIENX = 1<<TXINE;
 }
 
+void
+usb_request_bootloader(void)
+{
+}
+
 #if CONFIG_MACH_at90usb1286
 #define UHWCON_Init ((1<<UIMOD) | (1<<UVREGE))
 #define PLLCSR_Init ((1<<PLLP2) | (1<<PLLP0) | (1<<PLLE))

src/generic/usb_cdc.c

@@ -402,6 +402,15 @@ usb_req_set_configuration(struct usb_ctrlrequest *req)
 }
 
 static struct usb_cdc_line_coding line_coding;
+static uint8_t line_control_state;
+
+static void
+check_reboot(void)
+{
+    if (line_coding.dwDTERate == 1200 && !(line_control_state & 0x01))
+        // A baud of 1200 is an Arduino style request to enter the bootloader
+        usb_request_bootloader();
+}
 
 static void
 usb_req_set_line_coding(struct usb_ctrlrequest *req)
@@ -412,6 +421,7 @@ usb_req_set_line_coding(struct usb_ctrlrequest *req)
         return;
     }
     usb_do_xfer(&line_coding, sizeof(line_coding), UX_READ);
+    check_reboot();
 }
 
 static void
@@ -432,7 +442,9 @@ usb_req_set_line(struct usb_ctrlrequest *req)
         usb_do_stall();
         return;
     }
+    line_control_state = req->wValue;
     usb_do_xfer(NULL, 0, UX_SEND);
+    check_reboot();
 }
 
 static void

src/generic/usb_cdc.h

@@ -21,6 +21,7 @@ int_fast8_t usb_send_ep0_progmem(const void *data, uint_fast8_t len);
 void usb_stall_ep0(void);
 void usb_set_address(uint_fast8_t addr);
 void usb_set_configure(void);
+void usb_request_bootloader(void);
 
 // usb_cdc.c
 void usb_notify_bulk_in(void);

src/lpc176x/usbserial.c

@@ -241,6 +241,11 @@ usb_set_configure(void)
     usb_irq_enable();
 }
 
+void
+usb_request_bootloader(void)
+{
+}
+
 void
 usbserial_init(void)
 {

src/samd21/usbserial.c

@@ -168,6 +168,11 @@ usb_set_configure(void)
         USB_DEVICE_EPINTENSET_TRCPT0 | USB_DEVICE_EPINTENSET_TRCPT1);
 }
 
+void
+usb_request_bootloader(void)
+{
+}
+
 void
 usbserial_init(void)
 {

src/stm32f1/usbserial.c

@@ -211,6 +211,11 @@ usb_set_configure(void)
 {
 }
 
+void
+usb_request_bootloader(void)
+{
+}
+
 
 /****************************************************************
  * Setup and interrupts