From 9ac9aa989c89a1d6310160dd408820d1164d4dd7 Mon Sep 17 00:00:00 2001
From: Damien George <damien.p.george@gmail.com>
Date: Mon, 28 Jan 2019 16:16:03 +1100
Subject: [PATCH] esp32/machine_timer: Deinit all active timers on soft reset.

Otherwise they will keep triggering the callback and access invalid data on
the heap.
---
 ports/esp32/machine_timer.c | 23 +++++++++++++++++++++++
 ports/esp32/main.c          |  2 ++
 ports/esp32/modmachine.h    |  1 +
 ports/esp32/mpconfigport.h  |  3 +++
 4 files changed, 29 insertions(+)

diff --git a/ports/esp32/machine_timer.c b/ports/esp32/machine_timer.c
index 7dca9e0143..081a46b9c1 100644
--- a/ports/esp32/machine_timer.c
+++ b/ports/esp32/machine_timer.c
@@ -56,10 +56,14 @@ typedef struct _machine_timer_obj_t {
     mp_obj_t callback;
 
     intr_handle_t handle;
+
+    struct _machine_timer_obj_t *next;
 } machine_timer_obj_t;
 
 const mp_obj_type_t machine_timer_type;
 
+STATIC void machine_timer_disable(machine_timer_obj_t *self);
+
 STATIC esp_err_t check_esp_err(esp_err_t code) {
     if (code) {
         mp_raise_OSError(code);
@@ -68,6 +72,12 @@ STATIC esp_err_t check_esp_err(esp_err_t code) {
     return code;
 }
 
+void machine_timer_deinit_all(void) {
+    while (MP_STATE_PORT(machine_timer_obj_head) != NULL) {
+        machine_timer_disable(MP_STATE_PORT(machine_timer_obj_head));
+    }
+}
+
 STATIC void machine_timer_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     machine_timer_obj_t *self = self_in;
 
@@ -88,6 +98,7 @@ STATIC mp_obj_t machine_timer_make_new(const mp_obj_type_t *type, size_t n_args,
 
     self->group = (mp_obj_get_int(args[0]) >> 1) & 1;
     self->index = mp_obj_get_int(args[0]) & 1;
+    self->next = NULL;
 
     return self;
 }
@@ -98,6 +109,14 @@ STATIC void machine_timer_disable(machine_timer_obj_t *self) {
         esp_intr_free(self->handle);
         self->handle = NULL;
     }
+
+    // Remove the timer from the linked-list of active timers
+    for (machine_timer_obj_t **t = &MP_STATE_PORT(machine_timer_obj_head); *t; t = &(*t)->next) {
+        if (*t == self) {
+            *t = (*t)->next;
+            break;
+        }
+    }
 }
 
 STATIC void machine_timer_isr(void *self_in) {
@@ -131,6 +150,10 @@ STATIC void machine_timer_enable(machine_timer_obj_t *self) {
     check_esp_err(timer_enable_intr(self->group, self->index));
     check_esp_err(timer_isr_register(self->group, self->index, machine_timer_isr, (void*)self, TIMER_FLAGS, &self->handle));
     check_esp_err(timer_start(self->group, self->index));
+
+    // Add the timer to the linked-list of active timers
+    self->next = MP_STATE_PORT(machine_timer_obj_head);
+    MP_STATE_PORT(machine_timer_obj_head) = self;
 }
 
 STATIC mp_obj_t machine_timer_init_helper(machine_timer_obj_t *self, mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
diff --git a/ports/esp32/main.c b/ports/esp32/main.c
index 9ca88699d2..01d22d3e75 100644
--- a/ports/esp32/main.c
+++ b/ports/esp32/main.c
@@ -109,6 +109,8 @@ soft_reset:
         }
     }
 
+    machine_timer_deinit_all();
+
     #if MICROPY_PY_THREAD
     mp_thread_deinit();
     #endif
diff --git a/ports/esp32/modmachine.h b/ports/esp32/modmachine.h
index c8513a4711..b65b427b4e 100644
--- a/ports/esp32/modmachine.h
+++ b/ports/esp32/modmachine.h
@@ -22,5 +22,6 @@ extern const mp_obj_type_t machine_rtc_type;
 
 void machine_pins_init(void);
 void machine_pins_deinit(void);
+void machine_timer_deinit_all(void);
 
 #endif // MICROPY_INCLUDED_ESP32_MODMACHINE_H
diff --git a/ports/esp32/mpconfigport.h b/ports/esp32/mpconfigport.h
index 0f8deb11c3..a70f6d3180 100644
--- a/ports/esp32/mpconfigport.h
+++ b/ports/esp32/mpconfigport.h
@@ -210,9 +210,12 @@ extern const struct _mp_obj_module_t mp_module_onewire;
 
 #define MP_STATE_PORT MP_STATE_VM
 
+struct _machine_timer_obj_t;
+
 #define MICROPY_PORT_ROOT_POINTERS \
     const char *readline_hist[8]; \
     mp_obj_t machine_pin_irq_handler[40]; \
+    struct _machine_timer_obj_t *machine_timer_obj_head; \
 
 // type definitions for the specific machine