fix(freertos): sync signal from isr fixed (#6793)

Signed-off-by: Nicușor Cîțu <nicusor.citu@nxp.com>
Signed-off-by: Cosmin-Daniel Radu <cosmin.radu_1@nxp.com>
Co-authored-by: Nicușor Cîțu <nicusor.citu@nxp.com>

Kconfig

@@ -162,6 +162,15 @@ menu "LVGL configuration"
 			string "Custom OS include header"
 			default "stdint.h"
 			depends on LV_OS_CUSTOM
+
+        config LV_USE_FREERTOS_TASK_NOTIFY
+            bool "Use RTOS task with a direct notification for synchronization"
+            default y
+            depends on LV_OS_FREERTOS
+        help
+            Unblocking an RTOS task with a direct notification is 45% faster and uses less RAM
+            than unblocking a task using an intermediary object such as a binary semaphore.
+            RTOS task notifications can only be used when there is only one task that can be the recipient of the event.
 	endmenu
 
 	menu "Rendering Configuration"

env_support/cmake/esp.cmake

@@ -70,3 +70,9 @@ if(CONFIG_LV_ATTRIBUTE_FAST_MEM_USE_IRAM)
   target_compile_definitions(${COMPONENT_LIB}
                              PUBLIC "-DLV_ATTRIBUTE_FAST_MEM=IRAM_ATTR")
 endif()
+
+if(CONFIG_FREERTOS_SMP)
+    target_include_directories(${COMPONENT_LIB} PRIVATE "${IDF_PATH}/components/freertos/FreeRTOS-Kernel-SMP/include/freertos/")
+else()
+    target_include_directories(${COMPONENT_LIB} PRIVATE "${IDF_PATH}/components/freertos/FreeRTOS-Kernel/include/freertos/")
+endif()

lv_conf_template.h

@@ -111,6 +111,15 @@
 #if LV_USE_OS == LV_OS_CUSTOM
     #define LV_OS_CUSTOM_INCLUDE <stdint.h>
 #endif
+#if LV_USE_OS == LV_OS_FREERTOS
+	/*
+	 * Unblocking an RTOS task with a direct notification is 45% faster and uses less RAM
+	 * than unblocking a task using an intermediary object such as a binary semaphore.
+	 *
+	 * RTOS task notifications can only be used when there is only one task that can be the recipient of the event.
+	 */
+	#define LV_USE_FREERTOS_TASK_NOTIFY 1
+#endif
 
 /*========================
  * RENDERING CONFIGURATION

src/draw/nxp/vglite/lv_draw_vglite.c

@@ -340,9 +340,13 @@ static int32_t _vglite_wait_for_finish(lv_draw_unit_t * draw_unit)
     lv_draw_vglite_unit_t * draw_vglite_unit = (lv_draw_vglite_unit_t *) draw_unit;
     draw_vglite_unit->wait_for_finish = true;
 
+    /* Signal draw unit to finish its tasks and return READY state after completion. */
     if(draw_vglite_unit->inited)
         lv_thread_sync_signal(&draw_vglite_unit->sync);
 
+    /* Wait for finish now. */
+    lv_draw_dispatch_wait_for_request();
+
     return 1;
 }
 #endif

src/lv_conf_internal.h

@@ -282,6 +282,25 @@
         #endif
     #endif
 #endif
+#if LV_USE_OS == LV_OS_FREERTOS
+	/*
+	 * Unblocking an RTOS task with a direct notification is 45% faster and uses less RAM
+	 * than unblocking a task using an intermediary object such as a binary semaphore.
+	 *
+	 * RTOS task notifications can only be used when there is only one task that can be the recipient of the event.
+	 */
+	#ifndef LV_USE_FREERTOS_TASK_NOTIFY
+	    #ifdef LV_KCONFIG_PRESENT
+	        #ifdef CONFIG_LV_USE_FREERTOS_TASK_NOTIFY
+	            #define LV_USE_FREERTOS_TASK_NOTIFY CONFIG_LV_USE_FREERTOS_TASK_NOTIFY
+	        #else
+	            #define LV_USE_FREERTOS_TASK_NOTIFY 0
+	        #endif
+	    #else
+	        #define LV_USE_FREERTOS_TASK_NOTIFY 1
+	    #endif
+	#endif
+#endif
 
 /*========================
  * RENDERING CONFIGURATION

src/osal/lv_freertos.c

@@ -15,11 +15,7 @@
 #include "lv_os.h"
 #if LV_USE_OS == LV_OS_FREERTOS
 
-#if (ESP_PLATFORM)
+#include "atomic.h"
-    #include "freertos/atomic.h"
-#else
-    #include "atomic.h"
-#endif
 
 #include "../tick/lv_tick.h"
 #include "../misc/lv_log.h"
@@ -54,7 +50,9 @@ static void prvCondInit(lv_thread_sync_t * pxCond);
 
 static void prvCheckCondInit(lv_thread_sync_t * pxCond);
 
-#if !USE_FREERTOS_TASK_NOTIFY
+static void prvCheckCondInitIsr(lv_thread_sync_t * pxCond);
+
+#if !LV_USE_FREERTOS_TASK_NOTIFY
 static void prvTestAndDecrement(lv_thread_sync_t * pxCond,
                                 uint32_t ulLocalWaitingThreads);
 #endif
@@ -74,9 +72,13 @@ static void prvTestAndDecrement(lv_thread_sync_t * pxCond,
 #if (ESP_PLATFORM)
     #define _enter_critical()   taskENTER_CRITICAL(&critSectionMux);
     #define _exit_critical()    taskEXIT_CRITICAL(&critSectionMux);
+    #define _enter_critical_isr() taskENTER_CRITICAL_FROM_ISR();
+    #define _exit_critical_isr(x) taskEXIT_CRITICAL_FROM_ISR(x);
 #else
     #define _enter_critical()   taskENTER_CRITICAL();
     #define _exit_critical()    taskEXIT_CRITICAL();
+    #define _enter_critical_isr() taskENTER_CRITICAL_FROM_ISR();
+    #define _exit_critical_isr(x) taskEXIT_CRITICAL_FROM_ISR(x);
 #endif
 
 /**********************
@@ -195,20 +197,20 @@ lv_result_t lv_thread_sync_wait(lv_thread_sync_t * pxCond)
     /* If the cond is uninitialized, perform initialization. */
     prvCheckCondInit(pxCond);
 
-#if USE_FREERTOS_TASK_NOTIFY
+#if LV_USE_FREERTOS_TASK_NOTIFY
-    TaskHandle_t current_task_handle = xTaskGetCurrentTaskHandle();
+    TaskHandle_t xCurrentTaskHandle = xTaskGetCurrentTaskHandle();
 
     _enter_critical();
-    BaseType_t signal_sent = pxCond->xSyncSignal;
+    BaseType_t xSyncSygnal = pxCond->xSyncSignal;
     pxCond->xSyncSignal = pdFALSE;
-    if(signal_sent == pdFALSE) {
+    if(xSyncSygnal == pdFALSE) {
         /* The signal hasn't been sent yet. Tell the sender to notify this task */
-        pxCond->xTaskToNotify = current_task_handle;
+        pxCond->xTaskToNotify = xCurrentTaskHandle;
     }
     /* If we have a signal from the other task, we should not ask to be notified */
     _exit_critical();
 
-    if(signal_sent == pdFALSE) {
+    if(xSyncSygnal == pdFALSE) {
         /* Wait for other task to notify this task. */
         ulTaskNotifyTake(pdTRUE, portMAX_DELAY);
     }
@@ -275,20 +277,20 @@ lv_result_t lv_thread_sync_signal(lv_thread_sync_t * pxCond)
     /* If the cond is uninitialized, perform initialization. */
     prvCheckCondInit(pxCond);
 
-#if USE_FREERTOS_TASK_NOTIFY
+#if LV_USE_FREERTOS_TASK_NOTIFY
     _enter_critical();
-    TaskHandle_t task_to_notify = pxCond->xTaskToNotify;
+    TaskHandle_t xTaskToNotify = pxCond->xTaskToNotify;
     pxCond->xTaskToNotify = NULL;
-    if(task_to_notify == NULL) {
+    if(xTaskToNotify == NULL) {
         /* No task waiting to be notified. Send this signal for later */
         pxCond->xSyncSignal = pdTRUE;
     }
     /* If a task is already waiting, there is no need to set the sync signal */
     _exit_critical();
 
-    if(task_to_notify != NULL) {
+    if(xTaskToNotify != NULL) {
         /* There is a task waiting. Send a notification to it */
-        xTaskNotifyGive(task_to_notify);
+        xTaskNotifyGive(xTaskToNotify);
     }
     /* If there was no task waiting to be notified, we sent a signal for it to see later. */
 #else
@@ -329,13 +331,13 @@ lv_result_t lv_thread_sync_signal(lv_thread_sync_t * pxCond)
 
 lv_result_t lv_thread_sync_delete(lv_thread_sync_t * pxCond)
 {
-#if !USE_FREERTOS_TASK_NOTIFY
+#if !LV_USE_FREERTOS_TASK_NOTIFY
     /* Cleanup all resources used by the cond. */
     vSemaphoreDelete(pxCond->xCondWaitSemaphore);
     vSemaphoreDelete(pxCond->xSyncMutex);
     pxCond->ulWaitingThreads = 0;
-    pxCond->xSyncSignal = pdFALSE;
 #endif
+    pxCond->xSyncSignal = pdFALSE;
     pxCond->xIsInitialized = pdFALSE;
 
     return LV_RESULT_OK;
@@ -346,28 +348,28 @@ lv_result_t lv_thread_sync_signal_isr(lv_thread_sync_t * pxCond)
     BaseType_t xHigherPriorityTaskWoken = pdFALSE;
 
     /* If the cond is uninitialized, perform initialization. */
-    prvCheckCondInit(pxCond);
+    prvCheckCondInitIsr(pxCond);
 
-#if USE_FREERTOS_TASK_NOTIFY
+#if LV_USE_FREERTOS_TASK_NOTIFY
-    _enter_critical();
+    uint32_t mask = _enter_critical_isr();
-    TaskHandle_t task_to_notify = pxCond->xTaskToNotify;
+    TaskHandle_t xTaskToNotify = pxCond->xTaskToNotify;
     pxCond->xTaskToNotify = NULL;
-    if(task_to_notify == NULL) {
+    if(xTaskToNotify == NULL) {
         /* No task waiting to be notified. Send this signal for later */
         pxCond->xSyncSignal = pdTRUE;
     }
     /* If a task is already waiting, there is no need to set the sync signal */
-    _exit_critical();
+    _exit_critical_isr(mask);
 
-    if(task_to_notify != NULL) {
+    if(xTaskToNotify != NULL) {
         /* There is a task waiting. Send a notification to it */
-        vTaskNotifyGiveFromISR(task_to_notify, &xHigherPriorityTaskWoken);
+        vTaskNotifyGiveFromISR(xTaskToNotify, &xHigherPriorityTaskWoken);
         portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
     }
     /* If there was no task waiting to be notified, we sent a signal for it to see later. */
 #else
     /* Enter critical section to prevent preemption. */
-    _enter_critical();
+    uint32_t mask = _enter_critical_isr();
 
     pxCond->xSyncSignal = pdTRUE;
     BaseType_t xAnyHigherPriorityTaskWoken = pdFALSE;
@@ -378,7 +380,7 @@ lv_result_t lv_thread_sync_signal_isr(lv_thread_sync_t * pxCond)
         xHigherPriorityTaskWoken |= xAnyHigherPriorityTaskWoken;
     }
 
-    _exit_critical();
+    _exit_critical_isr(mask);
     portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
 #endif
 
@@ -470,7 +472,7 @@ static void prvCondInit(lv_thread_sync_t * pxCond)
     pxCond->xIsInitialized = pdTRUE;
     pxCond->xSyncSignal = pdFALSE;
 
-#if USE_FREERTOS_TASK_NOTIFY
+#if LV_USE_FREERTOS_TASK_NOTIFY
     pxCond->xTaskToNotify = NULL;
 #else
     pxCond->xCondWaitSemaphore = xSemaphoreCreateCounting(ulMAX_COUNT, 0U);
@@ -516,7 +518,27 @@ static void prvCheckCondInit(lv_thread_sync_t * pxCond)
     }
 }
 
-#if !USE_FREERTOS_TASK_NOTIFY
+static void prvCheckCondInitIsr(lv_thread_sync_t * pxCond)
+{
+    /* Check if the condition variable needs to be initialized. */
+    if(pxCond->xIsInitialized == pdFALSE) {
+        /* Cond initialization must be in a critical section to prevent two
+         * threads from initializing it at the same time. */
+        uint32_t mask = _enter_critical_isr();
+
+        /* Check again that the condition is still uninitialized, i.e. it wasn't
+         * initialized while this function was waiting to enter the critical
+         * section. */
+        if(pxCond->xIsInitialized == pdFALSE) {
+            prvCondInit(pxCond);
+        }
+
+        /* Exit the critical section. */
+        _exit_critical_isr(mask);
+    }
+}
+
+#if !LV_USE_FREERTOS_TASK_NOTIFY
 static void prvTestAndDecrement(lv_thread_sync_t * pxCond,
                                 uint32_t ulLocalWaitingThreads)
 {

src/osal/lv_freertos.h

@@ -37,14 +37,6 @@ extern "C" {
  *      DEFINES
  *********************/
 
-/*
- * Unblocking an RTOS task with a direct notification is 45% faster and uses less RAM
- * than unblocking a task using an intermediary object such as a binary semaphore.
- *
- * RTOS task notifications can only be used when there is only one task that can be the recipient of the event.
- */
-#define USE_FREERTOS_TASK_NOTIFY 1
-
 /**********************
  *      TYPEDEFS
  **********************/
@@ -64,7 +56,7 @@ typedef struct {
     BaseType_t
     xIsInitialized;                       /**< Set to pdTRUE if this condition variable is initialized, pdFALSE otherwise. */
     BaseType_t xSyncSignal;               /**< Set to pdTRUE if the thread is signaled, pdFALSE otherwise. */
-#if USE_FREERTOS_TASK_NOTIFY
+#if LV_USE_FREERTOS_TASK_NOTIFY
     TaskHandle_t xTaskToNotify;           /**< The task waiting to be signalled. NULL if nothing is waiting. */
 #else
     SemaphoreHandle_t xCondWaitSemaphore; /**< Threads block on this semaphore in lv_thread_sync_wait. */