Merge branch 'contrib/github_pr_15132_v5.3' into 'release/v5.3'

fix(newlib): usleep returning early (GitHub PR) (v5.3)

See merge request espressif/esp-idf!38709

components/cxx/test_apps/general/main/CMakeLists.txt

@@ -1,2 +1,2 @@
 idf_component_register(SRCS "test_cxx_general.cpp"
-                       PRIV_REQUIRES unity driver)
+                       PRIV_REQUIRES unity driver esp_timer)

components/cxx/test_apps/general/main/test_cxx_general.cpp

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2021-2024 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2021-2025 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -14,6 +14,9 @@
 #include "unity.h"
 #include "unity_test_utils.h"
 #include "soc/soc.h"
+#include <chrono>
+#include <thread>
+#include "esp_timer.h"
 
 extern "C" void setUp()
 {
@@ -197,7 +200,7 @@ struct PriorityInitTest {
 
 int PriorityInitTest::order = 0;
 
-// init_priority objects are initialized from the lowest to the heighest priority number
+// init_priority objects are initialized from the lowest to the highest priority number
 // Default init_priority is always the lowest (highest priority number)
 PriorityInitTest g_static_init_priority_test2;
 PriorityInitTest g_static_init_priority_test1 __attribute__((init_priority(1000)));
@@ -289,6 +292,29 @@ TEST_CASE("stack smashing protection CXX", "[stack_smash]")
     recur_and_smash_cxx();
 }
 
+TEST_CASE("test std::this_thread::sleep_for basic functionality", "[misc]")
+{
+    const int us_per_tick = portTICK_PERIOD_MS * 1000;
+
+    // Test sub-tick sleep
+    const auto short_sleep = std::chrono::microseconds(us_per_tick / 4);
+    int64_t start = esp_timer_get_time();
+    std::this_thread::sleep_for(short_sleep);
+    int64_t end = esp_timer_get_time();
+    int64_t elapsed_us = end - start;
+    printf("short sleep: %lld us\n", elapsed_us);
+    TEST_ASSERT_GREATER_OR_EQUAL(short_sleep.count(), elapsed_us);
+
+    // Test multi-tick sleep
+    const auto long_sleep = std::chrono::microseconds(us_per_tick * 2);
+    start = esp_timer_get_time();
+    std::this_thread::sleep_for(long_sleep);
+    end = esp_timer_get_time();
+    elapsed_us = end - start;
+    printf("long sleep: %lld us\n", elapsed_us);
+    TEST_ASSERT_GREATER_OR_EQUAL(long_sleep.count(), elapsed_us);
+}
+
 extern "C" void app_main(void)
 {
     printf("CXX GENERAL TEST\n");

components/driver/test_apps/legacy_mcpwm_driver/main/test_legacy_mcpwm.c

@@ -167,7 +167,7 @@ static uint32_t pcnt_get_pulse_number(pcnt_unit_handle_t pwm_pcnt_unit, int capt
     int count_value = 0;
     TEST_ESP_OK(pcnt_unit_clear_count(pwm_pcnt_unit));
     TEST_ESP_OK(pcnt_unit_start(pwm_pcnt_unit));
-    usleep(capture_window_ms * 1000);
+    vTaskDelay(pdMS_TO_TICKS(capture_window_ms));
     TEST_ESP_OK(pcnt_unit_stop(pwm_pcnt_unit));
     TEST_ESP_OK(pcnt_unit_get_count(pwm_pcnt_unit, &count_value));
     printf("count value: %d\r\n", count_value);

components/newlib/test_apps/newlib/main/test_time.c

@@ -1,11 +1,12 @@
 /*
- * SPDX-FileCopyrightText: 2015-2024 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2015-2025 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 #include <stdio.h>
 #include <string.h>
 #include <math.h>
+#include <unistd.h>
 #include "unity.h"
 #include <time.h>
 #include <sys/time.h>
@@ -93,6 +94,27 @@ TEST_CASE("Reading RTC registers on APP CPU doesn't affect clock", "[newlib]")
 
 #endif // (CONFIG_FREERTOS_NUMBER_OF_CORES == 2) && CONFIG_IDF_TARGET_ARCH_XTENSA
 
+TEST_CASE("test usleep basic functionality", "[newlib]")
+{
+    const int us_per_tick = portTICK_PERIOD_MS * 1000;
+
+    // Test sub-tick sleep such that usleep() uses ROM delay path
+    const int short_sleep_us = us_per_tick / 4;
+    int64_t start = esp_timer_get_time();
+    TEST_ASSERT_EQUAL(0, usleep(short_sleep_us));
+    int64_t end = esp_timer_get_time();
+    printf("short sleep: %lld us\n", end - start);
+    TEST_ASSERT_GREATER_OR_EQUAL(short_sleep_us, end - start);
+
+    // Test multi-tick sleep using vTaskDelay path
+    const int long_sleep_us = us_per_tick * 2;
+    start = esp_timer_get_time();
+    TEST_ASSERT_EQUAL(0, usleep(long_sleep_us));
+    end = esp_timer_get_time();
+    printf("long sleep: %lld us\n", end - start);
+    TEST_ASSERT_GREATER_OR_EQUAL(long_sleep_us, end - start);
+}
+
 TEST_CASE("test adjtime function", "[newlib]")
 {
     struct timeval tv_time;

components/newlib/time.c

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2015-2024 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2015-2025 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -207,10 +207,26 @@ int usleep(useconds_t us)
     if (us < us_per_tick) {
         esp_rom_delay_us((uint32_t) us);
     } else {
-        /* since vTaskDelay(1) blocks for anywhere between 0 and portTICK_PERIOD_MS,
-         * round up to compensate.
-         */
-        vTaskDelay((us + us_per_tick - 1) / us_per_tick);
+        /* vTaskDelay may return up to (n-1) tick periods due to the tick ISR
+           being asynchronous to the call. We must sleep at least the specified
+           time, or longer. Checking the monotonic clock allows making an
+           additional call to vTaskDelay when needed to ensure minimal time is
+           actually slept. Adding `us_per_tick - 1` prevents ever passing 0 to
+           vTaskDelay().
+        */
+        uint64_t now_us = esp_time_impl_get_time();
+        uint64_t target_us = now_us + us;
+        do {
+            vTaskDelay((((target_us - now_us) + us_per_tick - 1) / us_per_tick));
+            now_us = esp_time_impl_get_time();
+            /* It is possible that the time left until the target time is less
+             * than a tick period. However, we let usleep() to sleep for an
+             * entire tick period. This, could result in usleep() sleeping for
+             * a longer time than the requested time but that does not violate
+             * the spec of usleep(). Additionally, it allows FreeRTOS to schedule
+             * other tasks while the current task is sleeping.
+             */
+        } while (now_us < target_us);
     }
     return 0;
 }