Supervisor: move most of systick to the supervisor

This code is shared by most parts, except where not all the #ifdefs
inside the tick function were present in all ports.  This mostly would
have broken gamepad tick support on non-samd ports.

The "ms32" and "ms64" variants of the tick functions are introduced
because there is no 64-bit atomic read.  Disabling interrupts avoids
a low probability bug where milliseconds could be off by ~49.5 days
once every ~49.5 days (2^32 ms).

Avoiding disabling interrupts when only the low 32 bits are needed is a minor
optimization.

Testing performed: on metro m4 express, USB still works and
time.monotonic_ns() still counts up

5 files changed, 122 insertions, 6 deletions

diff --git a/supervisor/shared/rgb_led_status.c b/supervisor/shared/rgb_led_status.c
index 940cbf1f2..f751a7ffd 100644
--- a/supervisor/shared/rgb_led_status.c
+++ b/supervisor/shared/rgb_led_status.c
@@ -27,6 +27,7 @@
 #include "mphalport.h"
 #include "shared-bindings/microcontroller/Pin.h"
 #include "rgb_led_status.h"
+#include "supervisor/shared/tick.h"
 
 #ifdef MICROPY_HW_NEOPIXEL
 uint8_t rgb_status_brightness = 63;
@@ -360,7 +361,7 @@ void prep_rgb_status_animation(const pyexec_result_t* result,
                                rgb_status_animation_t* status) {
     #if defined(MICROPY_HW_NEOPIXEL) || (defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK)) || (defined(CP_RGB_STATUS_LED))
     new_status_color(ALL_DONE);
-    status->pattern_start = ticks_ms;
+    status->pattern_start = supervisor_ticks_ms32();
     status->safe_mode = safe_mode;
     status->found_main = found_main;
     status->total_exception_cycle = 0;
@@ -405,11 +406,11 @@ void prep_rgb_status_animation(const pyexec_result_t* result,
 
 void tick_rgb_status_animation(rgb_status_animation_t* status) {
     #if defined(MICROPY_HW_NEOPIXEL) || (defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK)) || (defined(CP_RGB_STATUS_LED))
-    uint32_t tick_diff = ticks_ms - status->pattern_start;
+    uint32_t tick_diff = supervisor_ticks_ms32() - status->pattern_start;
     if (status->ok) {
         // All is good. Ramp ALL_DONE up and down.
         if (tick_diff > ALL_GOOD_CYCLE_MS) {
-            status->pattern_start = ticks_ms;
+            status->pattern_start = supervisor_ticks_ms32();
             tick_diff = 0;
         }
 
@@ -424,7 +425,7 @@ void tick_rgb_status_animation(rgb_status_animation_t* status) {
         }
     } else {
         if (tick_diff > status->total_exception_cycle) {
-            status->pattern_start = ticks_ms;
+            status->pattern_start = supervisor_ticks_ms32();
             tick_diff = 0;
         }
         // First flash the file color.
diff --git a/supervisor/shared/safe_mode.c b/supervisor/shared/safe_mode.c
index d8d3ab379..363181da0 100644
--- a/supervisor/shared/safe_mode.c
+++ b/supervisor/shared/safe_mode.c
@@ -34,6 +34,7 @@
 #include "supervisor/shared/rgb_led_colors.h"
 #include "supervisor/shared/rgb_led_status.h"
 #include "supervisor/shared/translate.h"
+#include "supervisor/shared/tick.h"
 
 #define SAFE_MODE_DATA_GUARD 0xad0000af
 #define SAFE_MODE_DATA_GUARD_MASK 0xff0000ff
@@ -59,14 +60,14 @@ safe_mode_t wait_for_safe_mode_reset(void) {
     common_hal_digitalio_digitalinout_construct(&status_led, MICROPY_HW_LED_STATUS);
     common_hal_digitalio_digitalinout_switch_to_output(&status_led, true, DRIVE_MODE_PUSH_PULL);
     #endif
-    uint64_t start_ticks = ticks_ms;
+    uint64_t start_ticks = supervisor_ticks_ms64();
     uint64_t diff = 0;
     while (diff < 700) {
         #ifdef MICROPY_HW_LED_STATUS
         // Blink on for 100, off for 100, on for 100, off for 100 and on for 200
         common_hal_digitalio_digitalinout_set_value(&status_led, diff > 100 && diff / 100 != 2 && diff / 100 != 4);
         #endif
-        diff = ticks_ms - start_ticks;
+        diff = supervisor_ticks_ms64() - start_ticks;
     }
     #ifdef MICROPY_HW_LED_STATUS
     common_hal_digitalio_digitalinout_deinit(&status_led);
diff --git a/supervisor/shared/tick.c b/supervisor/shared/tick.c
new file mode 100644
index 000000000..d4a6ac5d7
--- /dev/null
+++ b/supervisor/shared/tick.c
@@ -0,0 +1,76 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Jeff Epler for Adafruit Industries
+ *
+ * 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.
+ */
+
+#include "supervisor/shared/tick.h"
+#include "supervisor/filesystem.h"
+#include "supervisor/shared/autoreload.h"
+
+static volatile uint64_t ticks_ms;
+
+#if CIRCUITPY_GAMEPAD
+#include "shared-module/gamepad/__init__.h"
+#endif
+
+#if CIRCUITPY_GAMEPADSHIFT
+#include "shared-module/gamepadshift/__init__.h"
+#endif
+
+#include "shared-bindings/microcontroller/__init__.h"
+
+void supervisor_tick(void) {
+
+    ticks_ms ++;
+
+
+#if CIRCUITPY_FILESYSTEM_FLUSH_INTERVAL_MS > 0
+    filesystem_tick();
+#endif
+#ifdef CIRCUITPY_AUTORELOAD_DELAY_MS
+    autoreload_tick();
+#endif
+#ifdef CIRCUITPY_GAMEPAD_TICKS
+    if (!(ticks_ms & CIRCUITPY_GAMEPAD_TICKS)) {
+        #if CIRCUITPY_GAMEPAD
+        gamepad_tick();
+        #endif
+        #if CIRCUITPY_GAMEPADSHIFT
+        gamepadshift_tick();
+        #endif
+    }
+#endif
+}
+
+uint64_t supervisor_ticks_ms64() {
+    uint64_t result;
+    common_hal_mcu_disable_interrupts();
+    result = ticks_ms;
+    common_hal_mcu_enable_interrupts();
+    return result;
+}
+
+uint32_t supervisor_ticks_ms32() {
+    return ticks_ms;
+}
diff --git a/supervisor/shared/tick.h b/supervisor/shared/tick.h
new file mode 100644
index 000000000..3defeb108
--- /dev/null
+++ b/supervisor/shared/tick.h
@@ -0,0 +1,37 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Jeff Epler for Adafruit Industries
+ *
+ * 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 __INCLUDED_SUPERVISOR_TICK_H
+#define __INCLUDED_SUPERVISOR_TICK_H
+
+#include <stdint.h>
+#include <stdatomic.h>
+
+extern void supervisor_tick(void);
+extern uint32_t supervisor_ticks_ms32(void);
+extern uint64_t supervisor_ticks_ms64(void);
+
+#endif
diff --git a/supervisor/supervisor.mk b/supervisor/supervisor.mk
index b2e4eb1dc..5e997ee78 100644
--- a/supervisor/supervisor.mk
+++ b/supervisor/supervisor.mk
@@ -10,6 +10,7 @@ SRC_SUPERVISOR = \
 	supervisor/shared/safe_mode.c \
 	supervisor/shared/stack.c \
 	supervisor/shared/status_leds.c \
+	supervisor/shared/tick.c \
 	supervisor/shared/translate.c
 
 ifndef $(NO_USB)