atmel/samd: Support CTRL-C on USB. This won't escape native code but it will cause Python code to stop.

Author: tannewt

atmel-samd/Makefile

@@ -81,7 +81,43 @@ endif
 ifeq ($(DEBUG), 1)
 CFLAGS += -O0 -ggdb
 else
-CFLAGS += -Os -DNDEBUG
+# was -Os
+CFLAGS += -O1 -ggdb -DNDEBUG
+# CFLAGS += -O0 \
+#   -ftree-ter \
+# 	-ftree-sra \
+# 	-ftree-slsr \
+# 	-ftree-sink \
+# 	-ftree-pta \
+# 	-ftree-fre \
+# 	-ftree-dse \
+# 	-ftree-dominator-opts \
+# 	-ftree-dce \
+# 	-ftree-copyrename \
+# 	-ftree-copy-prop \
+# 	-ftree-ch \
+# 	-ftree-ccp \
+# 	-ftree-bit-ccp \
+# 	-fsplit-wide-types \
+# 	-fshrink-wrap \
+# 	-fsection-anchors \
+# 	-fsched-pressure \
+# 	-fomit-frame-pointer \
+# 	-fmove-loop-invariants \
+# 	-fmerge-constants \
+# 	-fipa-reference \
+# 	-fipa-pure-const \
+# 	-fipa-profile \
+# 	-finline-functions-called-once \
+# 	-fif-conversion \
+# 	-fif-conversion2 \
+# 	-fguess-branch-probability \
+# 	-fforward-propagate \
+# 	-fdefer-pop \
+# 	-fcprop-registers \
+# 	-fcompare-elim \
+# 	-fcombine-stack-adjustments \
+# 	-fbranch-count-reg
 endif
 
 LIBS =

atmel-samd/boards/arduino_zero/conf_usb.h

@@ -34,7 +34,8 @@ extern void mp_cdc_disable(uint8_t port);
 #define  UDI_CDC_DEFAULT_PARITY           CDC_PAR_NONE
 #define  UDI_CDC_DEFAULT_DATABITS         8
 
-#define  UDI_CDC_RX_NOTIFY(port)
+#define  UDI_CDC_RX_NOTIFY(port)           usb_rx_notify()
+void usb_rx_notify(void);
 #define  UDI_CDC_SET_CODING_EXT(port,cfg)
 #define  UDI_CDC_SET_DTR_EXT(port,set)
 #define  UDI_CDC_SET_RTS_EXT(port,set)

atmel-samd/boards/feather_m0_ble/conf_usb.h

@@ -34,7 +34,8 @@ extern void mp_cdc_disable(uint8_t port);
 #define  UDI_CDC_DEFAULT_PARITY           CDC_PAR_NONE
 #define  UDI_CDC_DEFAULT_DATABITS         8
 
-#define  UDI_CDC_RX_NOTIFY(port)
+#define  UDI_CDC_RX_NOTIFY(port)           usb_rx_notify()
+void usb_rx_notify(void);
 #define  UDI_CDC_SET_CODING_EXT(port,cfg)
 #define  UDI_CDC_SET_DTR_EXT(port,set)
 #define  UDI_CDC_SET_RTS_EXT(port,set)

atmel-samd/main.c

@@ -59,6 +59,8 @@ int main(int argc, char **argv) {
     #endif
     mp_init();
 
+    MP_STATE_PORT(mp_kbd_exception) = mp_obj_new_exception(&mp_type_KeyboardInterrupt);
+
     pin_init0();
 
     #if MICROPY_REPL_EVENT_DRIVEN
@@ -101,6 +103,10 @@ mp_obj_t mp_builtin_open(uint n_args, const mp_obj_t *args, mp_map_t *kwargs) {
 }
 MP_DEFINE_CONST_FUN_OBJ_KW(mp_builtin_open_obj, 1, mp_builtin_open);
 
+void mp_keyboard_interrupt(void) {
+    MP_STATE_VM(mp_pending_exception) = MP_STATE_PORT(mp_kbd_exception);
+}
+
 void nlr_jump_fail(void *val) {
 }
 

atmel-samd/mpconfigport.h

@@ -114,6 +114,7 @@ extern const struct _mp_obj_module_t utime_module;
 #define MICROPY_PORT_ROOT_POINTERS \
     const char *readline_hist[8]; \
     vstr_t *repl_line; \
+    mp_obj_t mp_kbd_exception; \
     mp_obj_t pin_class_mapper; \
     mp_obj_t pin_class_map_dict; \
 

atmel-samd/mphalport.c

@@ -7,8 +7,29 @@
 #include "py/mpstate.h"
 
 #include "mpconfigboard.h"
+#include "mphalport.h"
+
+// Store received characters on our own so that we can filter control characters
+// and act immediately on CTRL-C for example.
+// This is adapted from asf/thirdparty/wireless/addons/sio2host
+
+// Receive buffer
+static uint8_t usb_rx_buf[USB_RX_BUF_SIZE];
+
+// Receive buffer head
+static uint8_t usb_rx_buf_head;
+
+// Receive buffer tail
+static uint8_t usb_rx_buf_tail;
+
+// Number of bytes in receive buffer
+static volatile uint8_t usb_rx_count;
 
 static volatile bool mp_cdc_enabled = false;
+
+void mp_keyboard_interrupt(void);
+int interrupt_char;
+
 extern struct usart_module usart_instance;
 
 bool mp_cdc_enable(uint8_t port)
@@ -22,11 +43,71 @@ void mp_cdc_disable(uint8_t port)
 	mp_cdc_enabled = false;
 }
 
+void usb_rx_notify(void)
+{
+    if (mp_cdc_enabled) {
+        while (udi_cdc_is_rx_ready()) {
+            uint8_t c;
+            c = udi_cdc_getc();
+
+            if (c == interrupt_char) {
+                mp_keyboard_interrupt();
+                // Don't put the interrupt into the buffer, just continue.
+                continue;
+            }
+
+            // Introducing critical section to avoid buffer corruption.
+            cpu_irq_disable();
+
+            // The count of characters present in receive buffer is
+            // incremented.
+            usb_rx_count++;
+            usb_rx_buf[usb_rx_buf_tail] = c;
+
+            if ((USB_RX_BUF_SIZE - 1) == usb_rx_buf_tail) {
+                // Reached the end of buffer, revert back to beginning of
+                // buffer.
+                usb_rx_buf_tail = 0x00;
+            } else {
+                usb_rx_buf_tail++;
+            }
+
+            cpu_irq_enable();
+        }
+    }
+}
+
+int receive_usb() {
+    if (0 == usb_rx_count) {
+        return 0;
+    }
+
+    if (USB_RX_BUF_SIZE <= usb_rx_count) {
+        // Bytes between head and tail are overwritten by new data. The
+        // oldest data in buffer is the one to which the tail is pointing. So
+        // reading operation should start from the tail.
+        usb_rx_buf_head = usb_rx_buf_tail;
+
+        // This is a buffer overflow case.But still only the number of bytes
+        // equivalent to full buffer size are useful.
+        usb_rx_count = USB_RX_BUF_SIZE;
+    }
+
+    // Copy from head.
+    int data = usb_rx_buf[usb_rx_buf_head];
+    usb_rx_buf_head++;
+    usb_rx_count--;
+    if ((USB_RX_BUF_SIZE) == usb_rx_buf_head) {
+      usb_rx_buf_head = 0;
+    }
+    return data;
+}
+
 int mp_hal_stdin_rx_chr(void) {
   for (;;) {
     #ifdef USB_REPL
-    if (mp_cdc_enabled && udi_cdc_is_rx_ready()) {
-      return udi_cdc_getc();
+    if (mp_cdc_enabled && usb_rx_count > 0) {
+      return receive_usb();
     }
     #endif
     #ifdef UART_REPL
@@ -41,10 +122,6 @@ int mp_hal_stdin_rx_chr(void) {
   }
 }
 
-//void mp_hal_stdout_tx_str(const char *str) {
-//    mp_hal_stdout_tx_strn(str, strlen(str));
-//}
-
 void mp_hal_stdout_tx_strn(const char *str, size_t len) {
   #ifdef UART_REPL
   usart_write_buffer_wait(&usart_instance, (uint8_t*) str, len);
@@ -57,6 +134,14 @@ void mp_hal_stdout_tx_strn(const char *str, size_t len) {
   #endif
 }
 
+void mp_hal_set_interrupt_char(int c) {
+    if (c != -1) {
+        mp_obj_exception_clear_traceback(MP_STATE_PORT(mp_kbd_exception));
+    }
+    extern int interrupt_char;
+    interrupt_char = c;
+}
+
 void mp_hal_delay_ms(mp_uint_t delay) {
   delay_ms(delay);
 }

atmel-samd/mphalport.h

@@ -1,2 +1,35 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Scott Shawcroft
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef __MICROPY_INCLUDED_ATMEL_SAMD_MPHALPORT_H__
+#define __MICROPY_INCLUDED_ATMEL_SAMD_MPHALPORT_H__
+
+#define USB_RX_BUF_SIZE 128
+
 static inline mp_uint_t mp_hal_ticks_ms(void) { return 0; }
-static inline void mp_hal_set_interrupt_char(char c) {}
+void mp_hal_set_interrupt_char(int c);
+
+#endif // __MICROPY_INCLUDED_ATMEL_SAMD_MPHALPORT_H__