atmel-samd: Support raw repl and soft reset to support ampy.

Closes #1. Also adds TX and RX led support on the Arduino Zero.

6 files changed, 108 insertions, 66 deletions

diff --git a/atmel-samd/Makefile b/atmel-samd/Makefile
index bd5bd1e1d..1acd8f34e 100644
--- a/atmel-samd/Makefile
+++ b/atmel-samd/Makefile
@@ -150,6 +150,7 @@ SRC_C = \
 	asf/sam0/utils/cmsis/samd21/source/gcc/startup_samd21.c \
 	asf/sam0/utils/cmsis/samd21/source/system_samd21.c \
 	asf/sam0/utils/syscalls/gcc/syscalls.c \
+	boards/$(BOARD)/init.c \
 	boards/$(BOARD)/pins.c \
 	lib/fatfs/ff.c \
 	lib/fatfs/option/ccsbcs.c \
diff --git a/atmel-samd/boards/arduino_zero/init.c b/atmel-samd/boards/arduino_zero/init.c
index 32fba3695..af8b08ff7 100644
--- a/atmel-samd/boards/arduino_zero/init.c
+++ b/atmel-samd/boards/arduino_zero/init.c
@@ -8,14 +8,24 @@
  * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
  */
 
-#include <asf.h>
-#include <board.h>
-#include <conf_board.h>
+#include "board.h"
+#include "conf_board.h"
+#include "mpconfigboard.h"
+#include "asf/sam0/drivers/port/port.h"
 
 void board_init(void)
 {
-	/* This function is meant to contain board-specific initialization code
-	 * for, e.g., the I/O pins. The initialization can rely on application-
-	 * specific board configuration, found in conf_board.h.
-	 */
+    /* This function is meant to contain board-specific initialization code
+     * for, e.g., the I/O pins. The initialization can rely on application-
+     * specific board configuration, found in conf_board.h.
+     */
+    struct port_config pin_conf;
+    port_get_config_defaults(&pin_conf);
+
+    pin_conf.direction  = PORT_PIN_DIR_OUTPUT;
+    port_pin_set_config(MICROPY_HW_LED_TX, &pin_conf);
+    port_pin_set_output_level(MICROPY_HW_LED_TX, true);
+
+    port_pin_set_config(MICROPY_HW_LED_RX, &pin_conf);
+    port_pin_set_output_level(MICROPY_HW_LED_RX, true);
 }
diff --git a/atmel-samd/boards/arduino_zero/mpconfigboard.h b/atmel-samd/boards/arduino_zero/mpconfigboard.h
index 4a2723fc7..fbebaed2d 100644
--- a/atmel-samd/boards/arduino_zero/mpconfigboard.h
+++ b/atmel-samd/boards/arduino_zero/mpconfigboard.h
@@ -5,3 +5,6 @@
 
 #define MICROPY_HW_BOARD_NAME "Arduino Zero"
 #define MICROPY_HW_MCU_NAME "samd21g18"
+
+#define MICROPY_HW_LED_TX   PIN_PA27
+#define MICROPY_HW_LED_RX   PIN_PB03
diff --git a/atmel-samd/boards/feather_m0_bluefruit_le/init.c b/atmel-samd/boards/feather_m0_bluefruit_le/init.c
index 32fba3695..88608c0fb 100644
--- a/atmel-samd/boards/feather_m0_bluefruit_le/init.c
+++ b/atmel-samd/boards/feather_m0_bluefruit_le/init.c
@@ -8,9 +8,8 @@
  * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
  */
 
-#include <asf.h>
-#include <board.h>
-#include <conf_board.h>
+#include "board.h"
+#include "conf_board.h"
 
 void board_init(void)
 {
diff --git a/atmel-samd/main.c b/atmel-samd/main.c
index c4db13470..4b7cafd4d 100644
--- a/atmel-samd/main.c
+++ b/atmel-samd/main.c
@@ -19,6 +19,7 @@
 #include "asf/sam0/drivers/port/port.h"
 #include "asf/sam0/drivers/sercom/usart/usart.h"
 #include "asf/sam0/drivers/system/system.h"
+#include <board.h>
 
 #include "mpconfigboard.h"
 #include "modmachine_pin.h"
@@ -158,16 +159,7 @@ void init_flash_fs() {
 static char *stack_top;
 static char heap[8192];
 
-int main(int argc, char **argv) {
-    // initialise the cpu and peripherals
-    #if MICROPY_MIN_USE_SAMD21_MCU
-    void samd21_init(void);
-    samd21_init();
-    #endif
-
-    int stack_dummy;
-    stack_top = (char*)&stack_dummy;
-
+void reset_mp() {
     #if MICROPY_ENABLE_GC
     gc_init(heap, heap + sizeof(heap));
     #endif
@@ -176,11 +168,22 @@ int main(int argc, char **argv) {
     MP_STATE_PORT(mp_kbd_exception) = mp_obj_new_exception(&mp_type_KeyboardInterrupt);
 
     pin_init0();
+}
+
+int main(int argc, char **argv) {
+    // initialise the cpu and peripherals
+    #if MICROPY_MIN_USE_SAMD21_MCU
+    void samd21_init(void);
+    samd21_init();
+    #endif
 
     // Initialise the local flash filesystem.
     // Create it if needed, mount in on /flash, and set it as current dir.
     init_flash_fs();
 
+    int stack_dummy;
+    reset_mp();
+
     #if MICROPY_REPL_EVENT_DRIVEN
     pyexec_event_repl_init();
     for (;;) {
@@ -190,10 +193,24 @@ int main(int argc, char **argv) {
         }
     }
     #else
-    pyexec_friendly_repl();
+    // Main script is finished, so now go into REPL mode.
+    // The REPL mode can change, or it can request a soft reset.
+    int exit_code = 0;
+    for (;;) {
+        if (pyexec_mode_kind == PYEXEC_MODE_RAW_REPL) {
+            exit_code = pyexec_raw_repl();
+        } else {
+            exit_code = pyexec_friendly_repl();
+        }
+        if (exit_code == PYEXEC_FORCED_EXIT) {
+            mp_hal_stdout_tx_str("soft reboot\r\n");
+            stack_top = (char*)&stack_dummy;
+            reset_mp();
+        } else if (exit_code != 0) {
+            break;
+        }
+    }
     #endif
-    //do_str("print('hello world!', list(x+1 for x in range(10)), end='eol\\n')", MP_PARSE_SINGLE_INPUT);
-    //do_str("for i in range(10):\r\n  print(i)", MP_PARSE_FILE_INPUT);
     mp_deinit();
     return 0;
 }
@@ -239,33 +256,34 @@ void MP_WEAK __assert_func(const char *file, int line, const char *func, const c
 struct usart_module usart_instance;
 
 void samd21_init(void) {
+    irq_initialize_vectors();
+    cpu_irq_enable();
 
-  irq_initialize_vectors();
-  cpu_irq_enable();
+    // Initialize the sleep manager
+    sleepmgr_init();
 
-  // Initialize the sleep manager
-  sleepmgr_init();
+    system_init();
 
-  system_init();
+    delay_init();
 
-  delay_init();
+    board_init();
 
-  // Uncomment to init PIN_PA17 for debugging.
-  // struct port_config pin_conf;
-  // port_get_config_defaults(&pin_conf);
-  //
-  // pin_conf.direction  = PORT_PIN_DIR_OUTPUT;
-  // port_pin_set_config(MICROPY_HW_LED1, &pin_conf);
-  // port_pin_set_output_level(MICROPY_HW_LED1, false);
+    // Uncomment to init PIN_PA17 for debugging.
+    // struct port_config pin_conf;
+    // port_get_config_defaults(&pin_conf);
+    //
+    // pin_conf.direction  = PORT_PIN_DIR_OUTPUT;
+    // port_pin_set_config(MICROPY_HW_LED1, &pin_conf);
+    // port_pin_set_output_level(MICROPY_HW_LED1, false);
 
-  #ifdef USB_REPL
-    udc_start();
-  #endif
+    #ifdef USB_REPL
+        udc_start();
+    #endif
 
-  // TODO(tannewt): Switch to proper pyb based UARTs.
-  #ifdef UART_REPL
-    configure_usart();
-  #endif
+    // TODO(tannewt): Switch to proper pyb based UARTs.
+    #ifdef UART_REPL
+        configure_usart();
+    #endif
 }
 
 #endif
diff --git a/atmel-samd/mphalport.c b/atmel-samd/mphalport.c
index 29f29ff1f..f5002b303 100644
--- a/atmel-samd/mphalport.c
+++ b/atmel-samd/mphalport.c
@@ -2,6 +2,7 @@
 
 #include "asf/common/services/usb/class/cdc/device/udi_cdc.h"
 #include "asf/common2/services/delay/delay.h"
+#include "asf/sam0/drivers/port/port.h"
 #include "asf/sam0/drivers/sercom/usart/usart.h"
 #include "py/mphal.h"
 #include "py/mpstate.h"
@@ -104,34 +105,44 @@ int receive_usb() {
 }
 
 int mp_hal_stdin_rx_chr(void) {
-  for (;;) {
-    #ifdef USB_REPL
-    if (mp_cdc_enabled && usb_rx_count > 0) {
-      return receive_usb();
+    for (;;) {
+        #ifdef USB_REPL
+        if (mp_cdc_enabled && usb_rx_count > 0) {
+            #ifdef MICROPY_HW_LED_RX
+            port_pin_toggle_output_level(MICROPY_HW_LED_RX);
+            #endif
+            return receive_usb();
+        }
+        #endif
+        #ifdef UART_REPL
+        uint16_t temp;
+        if (usart_read_wait(&usart_instance, &temp) == STATUS_OK) {
+            #ifdef MICROPY_HW_LED_RX
+            port_pin_toggle_output_level(MICROPY_HW_LED_RX);
+            #endif
+            return temp;
+        }
+        #endif
+        // TODO(tannewt): Figure out how we can sleep while waiting for input and
+        // add it here. The current UART implementation doesn't cause a wake.
+        //__WFI();
     }
+}
+
+void mp_hal_stdout_tx_strn(const char *str, size_t len) {
+    #ifdef MICROPY_HW_LED_TX
+    port_pin_toggle_output_level(MICROPY_HW_LED_TX);
     #endif
+
     #ifdef UART_REPL
-    uint16_t temp;
-    if (usart_read_wait(&usart_instance, &temp) == STATUS_OK) {
-      return temp;
-    }
+    usart_write_buffer_wait(&usart_instance, (uint8_t*) str, len);
     #endif
-    // TODO(tannewt): Figure out how we can sleep while waiting for input and
-    // add it here. The current UART implementation doesn't cause a wake.
-    //__WFI();
-  }
-}
 
-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);
-  #endif
-
-  #ifdef USB_REPL
-  if (mp_cdc_enabled && udi_cdc_is_tx_ready()) {
-    udi_cdc_write_buf(str, len);
-  }
-  #endif
+    #ifdef USB_REPL
+    if (mp_cdc_enabled && udi_cdc_is_tx_ready()) {
+        udi_cdc_write_buf(str, len);
+    }
+    #endif
 }
 
 void mp_hal_set_interrupt_char(int c) {