From 0ca995ad8b0fcc28609703c130c2fadf518ee5d4 Mon Sep 17 00:00:00 2001
From: Rahix <rahix@rahix.de>
Date: Thu, 4 Jul 2019 10:04:23 +0200
Subject: [PATCH] feat(epicardium): Enable tickless idle
---
epicardium/FreeRTOSConfig.h | 25 +++++++++++-
epicardium/api/common.h | 1 +
epicardium/api/dispatcher.c | 31 +++++++++++++--
epicardium/api/dispatcher.h | 17 ++++++--
epicardium/main.c | 63 ++++++++++++++++++++++++------
epicardium/serial.c | 77 ++++++++++++++++++++++++++++---------
6 files changed, 176 insertions(+), 38 deletions(-)
diff --git a/epicardium/FreeRTOSConfig.h b/epicardium/FreeRTOSConfig.h
index 26e51bc4c..76ae165a9 100644
--- a/epicardium/FreeRTOSConfig.h
+++ b/epicardium/FreeRTOSConfig.h
@@ -1,6 +1,9 @@
#ifndef FREERTOS_CONFIG_H
#define FREERTOS_CONFIG_H
+#define MXC_ASSERT_ENABLE
+#include "mxc_assert.h"
+
#include "max32665.h"
/* CMSIS keeps a global updated with current system clock in Hz */
@@ -22,7 +25,14 @@
#define configMAX_SYSCALL_INTERRUPT_PRIORITY ( ( unsigned char ) 5 << ( 8 - configPRIO_BITS) )
/* We want to use preemption to easier integrate components */
-#define configUSE_PREEMPTION 1
+/* TODO: Figure out why turning this on does not work ... */
+#define configUSE_PREEMPTION 0
+
+/*
+ * Tickless idle from the FreeRTOS port + our own hooks (defined further down in
+ * this file)
+ */
+#define configUSE_TICKLESS_IDLE 1
/* TODO: Adjust */
#define configUSE_IDLE_HOOK 0
@@ -42,4 +52,17 @@
#define xPortPendSVHandler PendSV_Handler
#define xPortSysTickHandler SysTick_Handler
+/* Assert */
+#define configASSERT(x) MXC_ASSERT(x)
+
+/* Tickless idle hooks */
+typedef uint32_t TickType_t;
+void pre_idle_sleep(TickType_t xExpectedIdleTime);
+#define configPRE_SLEEP_PROCESSING(xModifiableIdleTime) \
+ pre_idle_sleep(xModifiableIdleTime); xModifiableIdleTime = 0
+
+void post_idle_sleep(TickType_t xExpectedIdleTime);
+#define configPOST_SLEEP_PROCESSING(xExpectedIdleTime) \
+ post_idle_sleep(xExpectedIdleTime)
+
#endif /* FREERTOS_CONFIG_H */
diff --git a/epicardium/api/common.h b/epicardium/api/common.h
index 70b24a35a..5b435fa58 100644
--- a/epicardium/api/common.h
+++ b/epicardium/api/common.h
@@ -1,4 +1,5 @@
#include <stdint.h>
+#include <stdbool.h>
/*
* Semaphore used for API synchronization.
diff --git a/epicardium/api/dispatcher.c b/epicardium/api/dispatcher.c
index d499bd16f..a6e5cf415 100644
--- a/epicardium/api/dispatcher.c
+++ b/epicardium/api/dispatcher.c
@@ -18,20 +18,45 @@ int api_dispatcher_init()
return ret;
}
-api_id_t api_dispatcher_poll()
+static bool event_ready = false;
+
+bool api_dispatcher_poll_once()
{
- api_id_t id = 0;
+ if (event_ready) {
+ return false;
+ }
+
while (SEMA_GetSema(_API_SEMAPHORE) == E_BUSY) {}
if (API_CALL_MEM->call_flag != _API_FLAG_CALLING) {
SEMA_FreeSema(_API_SEMAPHORE);
+ return false;
+ }
+
+ event_ready = true;
+ return true;
+}
+
+bool api_dispatcher_poll()
+{
+ if (event_ready) {
+ return true;
+ }
+
+ return api_dispatcher_poll_once();
+}
+
+api_id_t api_dispatcher_exec()
+{
+ if (!event_ready) {
return 0;
}
- id = API_CALL_MEM->id;
+ api_id_t id = API_CALL_MEM->id;
__api_dispatch_call(id, API_CALL_MEM->buffer);
API_CALL_MEM->call_flag = _API_FLAG_RETURNED;
+ event_ready = false;
SEMA_FreeSema(_API_SEMAPHORE);
/* Notify the caller that we returned */
diff --git a/epicardium/api/dispatcher.h b/epicardium/api/dispatcher.h
index 1385b7194..4098b162b 100644
--- a/epicardium/api/dispatcher.h
+++ b/epicardium/api/dispatcher.h
@@ -7,11 +7,20 @@
int api_dispatcher_init();
/*
- * Attempt to dispatch a call, if the caller has requested one.
- * Will return 0 if no call was dispatched and the ID of the dispatched
- * call otherwise.
+ * Check whether the other core requested a call. If this function returns
+ * true, the dispatcher should call api_dispatcher_exec() to actually dispatch
+ * the call. Consecutive calls to this function will return false. Use
+ * api_dispatcher_poll() if your need to recheck.
*/
-api_id_t api_dispatcher_poll();
+bool api_dispatcher_poll_once();
+bool api_dispatcher_poll();
+
+/*
+ * Attempt to dispatch a call, if one had been polled using
+ * api_dispatcher_poll(). Will return 0 if no call was dispatched or the ID of
+ * the dispatched call otherwise.
+ */
+api_id_t api_dispatcher_exec();
/* This function is defined by the generated dispatcher code */
void __api_dispatch_call(api_id_t id, void*buffer);
diff --git a/epicardium/main.c b/epicardium/main.c
index 3490b026d..cc2d0a4f3 100644
--- a/epicardium/main.c
+++ b/epicardium/main.c
@@ -12,17 +12,65 @@
#include "FreeRTOS.h"
#include "task.h"
+static TaskHandle_t dispatcher_task_id;
+
+/* TODO: Move out of main.c */
void epic_leds_set(int led, uint8_t r, uint8_t g, uint8_t b)
{
leds_set(led, r, g, b);
leds_update();
}
+/*
+ * This hook is called before FreeRTOS enters tickless idle.
+ */
+void pre_idle_sleep(TickType_t xExpectedIdleTime)
+{
+ if (xExpectedIdleTime > 0) {
+ /*
+ * WFE because the other core should be able to notify
+ * epicardium if it wants to issue an API call.
+ */
+ __asm volatile( "dsb" ::: "memory" );
+ __asm volatile( "wfe" );
+ __asm volatile( "isb" );
+ }
+}
+
+/*
+ * This hook is called after FreeRTOS exits tickless idle.
+ */
+void post_idle_sleep(TickType_t xExpectedIdleTime)
+{
+ /* Check whether a new API call was issued. */
+ if (api_dispatcher_poll_once()) {
+ xTaskNotifyGive(dispatcher_task_id);
+ }
+}
+
+#if 0
+void vPortSuppressTicksAndSleep(TickType_t xExpectedIdleTime)
+{
+ if (xExpectedIdleTime > 0) {
+ __WFE();
+ if (api_dispatcher_poll()) {
+ xTaskNotifyGive(dispatcher_task_id);
+ }
+ }
+}
+#endif
+
+/*
+ * API dispatcher task. This task will sleep until an API call is issued and
+ * then wake up to dispatch it.
+ */
void vApiDispatcher(void*pvParameters)
{
while (1) {
- api_dispatcher_poll();
- vTaskDelay(portTICK_PERIOD_MS * 10);
+ if (api_dispatcher_poll()) {
+ api_dispatcher_exec();
+ }
+ ulTaskNotifyTake(pdTRUE, portMAX_DELAY);
}
}
@@ -84,7 +132,7 @@ int main(void)
configMINIMAL_STACK_SIZE,
NULL,
tskIDLE_PRIORITY + 2,
- NULL
+ &dispatcher_task_id
) != pdPASS) {
printf("Failed to create api dispatcher task!\n");
abort();
@@ -97,12 +145,5 @@ int main(void)
core1_start();
vTaskStartScheduler();
- printf("ERROR: FreeRTOS did not start due to above error!\n");
-
-#if 0
- while(1) {
- __WFE();
- api_dispatcher_poll();
- }
-#endif
+ printf("ERROR: FreeRTOS did not start due to unknown error!\n");
}
diff --git a/epicardium/serial.c b/epicardium/serial.c
index a891f5103..0b956422a 100644
--- a/epicardium/serial.c
+++ b/epicardium/serial.c
@@ -3,6 +3,7 @@
#include "serial.h"
+#include "max32665.h"
#include "cdcacm.h"
#include "uart.h"
#include "tmr_utils.h"
@@ -11,16 +12,26 @@
#include "task.h"
#include "queue.h"
-extern mxc_uart_regs_t * ConsoleUart;
+/* Task ID for the serial handler */
+TaskHandle_t serial_task_id;
+/* The serial console in use (UART0) */
+extern mxc_uart_regs_t* ConsoleUart;
+/* Read queue, filled by both UART and CDCACM */
static QueueHandle_t read_queue;
+/*
+ * API-call to write a string. Output goes to both CDCACM and UART
+ */
void epic_uart_write_str(char*str, intptr_t length)
{
UART_Write(ConsoleUart, (uint8_t*)str, length);
cdcacm_write((uint8_t*)str, length);
}
+/*
+ * Blocking API-call to read a character from the queue.
+ */
char epic_uart_read_chr(void)
{
char chr;
@@ -28,11 +39,39 @@ char epic_uart_read_chr(void)
return chr;
}
+/* Interrupt handler needed for SDK UART implementation */
+void UART0_IRQHandler(void)
+{
+ UART_Handler(ConsoleUart);
+}
+
+static void uart_callback(uart_req_t*req, int error)
+{
+ BaseType_t xHigherPriorityTaskWoken = pdFALSE;
+ vTaskNotifyGiveFromISR(serial_task_id, &xHigherPriorityTaskWoken);
+ portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
+}
+
+static void enqueue_char(char chr)
+{
+ if (chr == 0x3) {
+ /* Control-C */
+ TMR_TO_Start(MXC_TMR5, 1, 0);
+ }
+
+ if (xQueueSend(read_queue, &chr, 100) == errQUEUE_FULL) {
+ /* Queue overran, wait a bit */
+ vTaskDelay(portTICK_PERIOD_MS * 50);
+ }
+}
+
void vSerialTask(void*pvParameters)
{
static uint8_t buffer[sizeof(char) * SERIAL_READ_BUFFER_SIZE];
static StaticQueue_t read_queue_data;
+ serial_task_id = xTaskGetCurrentTaskHandle();
+
/* Setup read queue */
read_queue = xQueueCreateStatic(
SERIAL_READ_BUFFER_SIZE,
@@ -44,31 +83,31 @@ void vSerialTask(void*pvParameters)
/* Setup UART interrupt */
NVIC_ClearPendingIRQ(UART0_IRQn);
NVIC_DisableIRQ(UART0_IRQn);
- NVIC_SetPriority(UART0_IRQn, 1);
+ NVIC_SetPriority(UART0_IRQn, 6);
NVIC_EnableIRQ(UART0_IRQn);
- while (1) {
- char chr;
-
- /* TODO: Wait for interrupt on either device */
- vTaskDelay(portTICK_PERIOD_MS * 10);
+ unsigned char data;
+ uart_req_t read_req = {
+ .data = &data,
+ .len = 1,
+ .callback = uart_callback,
+ };
- if(UART_NumReadAvail(ConsoleUart) > 0) {
- chr = UART_ReadByte(ConsoleUart);
- } else if(cdcacm_num_read_avail() > 0) {
- chr = cdcacm_read();
- } else {
- continue;
+ while (1) {
+ int ret = UART_ReadAsync(ConsoleUart, &read_req);
+ if (ret != E_NO_ERROR && ret != E_BUSY) {
+ printf("error reading uart: %d\n", ret);
+ vTaskDelay(portMAX_DELAY);
}
- if (chr == 0x3) {
- /* Control-C */
- TMR_TO_Start(MXC_TMR5, 1, 0);
+ ulTaskNotifyTake(pdTRUE, portTICK_PERIOD_MS * 1000);
+
+ if (read_req.num > 0) {
+ enqueue_char(*read_req.data);
}
- if (xQueueSend(read_queue, &chr, 100) == errQUEUE_FULL) {
- /* Queue overran, wait a bit */
- vTaskDelay(portTICK_PERIOD_MS * 50);
+ while (UART_NumReadAvail(ConsoleUart) > 0) {
+ enqueue_char(UART_ReadByte(ConsoleUart));
}
}
}
--
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