From 79a0d3d56952fbea42d96a118a53f839dceaa21f Mon Sep 17 00:00:00 2001
From: Rahix <rahix@rahix.de>
Date: Fri, 3 Apr 2020 13:13:07 +0200
Subject: [PATCH] feat(interrupts): Dispatch interrupts asynchroneously
Instead of blocking the triggering task when core 1 is still busy
handling the previous interrupt, offload interrupt dispatching into
a separate task. This is the first step towards making API-calls
interrupt safe.
Next to the async triggering, the synchroneous mechanism is retained for
special cases where async does not work (e.g. because of spin-locks).
Currently, there is only one such case when resetting core 1 (triggering
EPIC_INT_RESET).
Signed-off-by: Rahix <rahix@rahix.de>
---
epicardium/api/control.c | 11 +++++--
epicardium/main.c | 10 ++++++
epicardium/modules/interrupts.c | 57 +++++++++++++++++++++++++++++++++
epicardium/modules/modules.h | 2 ++
4 files changed, 77 insertions(+), 3 deletions(-)
diff --git a/epicardium/api/control.c b/epicardium/api/control.c
index f59978842..deff43301 100644
--- a/epicardium/api/control.c
+++ b/epicardium/api/control.c
@@ -9,7 +9,7 @@
#include "tmr.h"
static void __core1_init(void);
-extern void interrupt_trigger(api_int_id_t id);
+extern void interrupt_trigger_sync(api_int_id_t id);
struct core1_info {
/* Location of core1's interrupt vector table */
@@ -206,8 +206,13 @@ void core1_boot(void)
void core1_trigger_reset(void)
{
- /* Signal core 1 that we intend to load a new payload. */
- interrupt_trigger(EPIC_INT_RESET);
+ /*
+ * Signal core 1 that we intend to load a new payload.
+ *
+ * This needs to be synchroneous because otherwise we will deadlock
+ * (Lifecycle task busy-spins and interrupt can never get dispatched).
+ */
+ interrupt_trigger_sync(EPIC_INT_RESET);
}
void core1_wait_ready(void)
diff --git a/epicardium/main.c b/epicardium/main.c
index c5e2768c3..89054e9e1 100644
--- a/epicardium/main.c
+++ b/epicardium/main.c
@@ -133,6 +133,16 @@ int main(void)
&dispatcher_task_id) != pdPASS) {
panic("Failed to create %s task!", "API Dispatcher");
}
+ /* Interrupts */
+ if (xTaskCreate(
+ vInterruptsTask,
+ (const char *)"Interrupt Dispatcher",
+ configMINIMAL_STACK_SIZE,
+ NULL,
+ tskIDLE_PRIORITY + 2,
+ NULL) != pdPASS) {
+ panic("Failed to create %s task!", "Interrupt Dispatcher");
+ }
/* BLE */
if (ble_shall_start()) {
diff --git a/epicardium/modules/interrupts.c b/epicardium/modules/interrupts.c
index e33e35769..0ead54fc5 100644
--- a/epicardium/modules/interrupts.c
+++ b/epicardium/modules/interrupts.c
@@ -1,4 +1,5 @@
#include "modules/mutex.h"
+#include "modules/log.h"
#include "epicardium.h"
#include "api/interrupt-sender.h"
#include <assert.h>
@@ -14,11 +15,28 @@ struct interrupt_priv {
static struct interrupt_priv interrupt_data;
static struct mutex interrupt_mutex;
+static TaskHandle_t interrupts_task;
void interrupt_trigger(api_int_id_t id)
{
assert(id < EPIC_INT_NUM);
+ mutex_lock(&interrupt_mutex);
+
+ if (interrupt_data.int_enabled[id]) {
+ interrupt_data.int_pending[id] = true;
+ interrupt_data.has_pending = true;
+ mutex_unlock(&interrupt_mutex);
+ xTaskNotifyGive(interrupts_task);
+ } else {
+ mutex_unlock(&interrupt_mutex);
+ }
+}
+
+void interrupt_trigger_sync(api_int_id_t id)
+{
+ assert(id < EPIC_INT_NUM);
+
mutex_lock(&interrupt_mutex);
if (!interrupt_data.int_enabled[id])
goto out;
@@ -97,3 +115,42 @@ int epic_interrupt_disable(api_int_id_t int_id)
return 0;
}
/* }}} */
+
+void vInterruptsTask(void *pvParameters)
+{
+ interrupts_task = xTaskGetCurrentTaskHandle();
+
+ while (true) {
+ mutex_lock(&interrupt_mutex);
+
+ if (!interrupt_data.has_pending) {
+ /* Wait for a wakeup event from interrupt_trigger() */
+ mutex_unlock(&interrupt_mutex);
+ ulTaskNotifyTake(pdTRUE, portMAX_DELAY);
+ mutex_lock(&interrupt_mutex);
+ }
+
+ while (!api_interrupt_is_ready()) {
+ mutex_unlock(&interrupt_mutex);
+ vTaskDelay(pdMS_TO_TICKS(5));
+ mutex_lock(&interrupt_mutex);
+ }
+
+ api_int_id_t current_irq = EPIC_INT_NUM;
+ for (size_t i = 0; i < EPIC_INT_NUM; i++) {
+ if (interrupt_data.int_pending[i]) {
+ current_irq = i;
+ interrupt_data.int_pending[i] = false;
+ break;
+ }
+ }
+
+ if (current_irq == EPIC_INT_NUM) {
+ interrupt_data.has_pending = false;
+ } else if (interrupt_data.int_enabled[current_irq]) {
+ api_interrupt_trigger(current_irq);
+ }
+
+ mutex_unlock(&interrupt_mutex);
+ }
+}
diff --git a/epicardium/modules/modules.h b/epicardium/modules/modules.h
index 534901c5c..c26a1ce6c 100644
--- a/epicardium/modules/modules.h
+++ b/epicardium/modules/modules.h
@@ -31,9 +31,11 @@ void return_to_menu(void);
/* ---------- Interrupts --------------------------------------------------- */
void interrupt_init(void);
void interrupt_trigger(api_int_id_t id);
+void interrupt_trigger_sync(api_int_id_t id);
void interrupt_trigger_unsafe(api_int_id_t id) __attribute__((deprecated(
"interrupt_trigger_unsafe() is racy and only exists for legacy code."
)));
+void vInterruptsTask(void *pvParameters);
/* ---------- Serial ------------------------------------------------------- */
#define SERIAL_READ_BUFFER_SIZE 128
--
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