From e64f3d43ad8f5dcbdff62865bacf1a56a464221f Mon Sep 17 00:00:00 2001
From: Konstantin Kondrashov <konstantin@espressif.com>
Date: Fri, 17 May 2019 21:27:05 +0800
Subject: [PATCH 1/2] i2c: Fix ticks_to_wait when 0 or time expired

Closes: https://github.com/espressif/esp-idf/issues/3301

Closes: IDFGH-964
---
 components/driver/i2c.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/components/driver/i2c.c b/components/driver/i2c.c
index 6d9a5c9f2..d9004db13 100644
--- a/components/driver/i2c.c
+++ b/components/driver/i2c.c
@@ -1380,13 +1380,18 @@ int i2c_slave_write_buffer(i2c_port_t i2c_num, uint8_t* data, int size, TickType
 
     portBASE_TYPE res;
     int cnt = 0;
-    portTickType ticks_end = xTaskGetTickCount() + ticks_to_wait;
+    portTickType ticks_start = xTaskGetTickCount();
 
     res = xSemaphoreTake(p_i2c->slv_tx_mux, ticks_to_wait);
     if (res == pdFALSE) {
         return 0;
     }
-    ticks_to_wait = ticks_end - xTaskGetTickCount();
+    TickType_t ticks_end = xTaskGetTickCount();
+    if (ticks_end - ticks_start > ticks_to_wait) {
+        ticks_to_wait = 0;
+    } else {
+        ticks_to_wait = ticks_to_wait - (ticks_end - ticks_start);
+    }
     res = xRingbufferSend(p_i2c->tx_ring_buf, data, size, ticks_to_wait);
     if (res == pdFALSE) {
         cnt = 0;
@@ -1421,18 +1426,28 @@ int i2c_slave_read_buffer(i2c_port_t i2c_num, uint8_t* data, size_t max_size, Ti
 
     i2c_obj_t* p_i2c = p_i2c_obj[i2c_num];
     portBASE_TYPE res;
-    portTickType ticks_end = xTaskGetTickCount() + ticks_to_wait;
+    portTickType ticks_start = xTaskGetTickCount();
     res = xSemaphoreTake(p_i2c->slv_rx_mux, ticks_to_wait);
     if (res == pdFALSE) {
         return 0;
     }
-    ticks_to_wait = ticks_end - xTaskGetTickCount();
+    TickType_t ticks_end = xTaskGetTickCount();
+    if (ticks_end - ticks_start > ticks_to_wait) {
+        ticks_to_wait = 0;
+    } else {
+        ticks_to_wait = ticks_to_wait - (ticks_end - ticks_start);
+    }
     int cnt = i2c_slave_read(i2c_num, data, max_size, ticks_to_wait);
     if (cnt > 0) {
         I2C_ENTER_CRITICAL(&i2c_spinlock[i2c_num]);
         I2C[i2c_num]->int_ena.rx_fifo_full = 1;
         I2C_EXIT_CRITICAL(&i2c_spinlock[i2c_num]);
-        ticks_to_wait = ticks_end - xTaskGetTickCount();
+        ticks_end = xTaskGetTickCount();
+        if (ticks_end - ticks_start > ticks_to_wait) {
+            ticks_to_wait = 0;
+        } else {
+            ticks_to_wait = ticks_to_wait - (ticks_end - ticks_start);
+        }
         if (cnt < max_size && ticks_to_wait > 0) {
             cnt += i2c_slave_read(i2c_num, data + cnt, max_size - cnt, ticks_to_wait);
         }

From db8ddf050fd421e3eba1a575c9f3cdfd130edd57 Mon Sep 17 00:00:00 2001
From: Konstantin Kondrashov <konstantin@espressif.com>
Date: Tue, 4 Jun 2019 12:17:55 +0800
Subject: [PATCH 2/2] driver: Add uart and i2c UTs to check ticks_to_wait in
 some functions

---
 components/driver/test/test_uart.c | 50 ++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/components/driver/test/test_uart.c b/components/driver/test/test_uart.c
index 370f00ffe..db2146efd 100644
--- a/components/driver/test/test_uart.c
+++ b/components/driver/test/test_uart.c
@@ -118,6 +118,56 @@ static void uart_config(uint32_t baud_rate, bool use_ref_tick)
     uart_driver_install(UART_NUM1, BUF_SIZE * 2, BUF_SIZE * 2, 20, NULL, 0);
 }
 
+static volatile bool exit_flag;
+
+static void test_task(void *pvParameters)
+{
+    xSemaphoreHandle *sema = (xSemaphoreHandle *) pvParameters;
+    char* data = (char *) malloc(256);
+
+    while (exit_flag == false) {
+        uart_tx_chars(UART_NUM1, data, 256);
+        // The uart_wait_tx_done() function does not block anything if ticks_to_wait = 0.
+        uart_wait_tx_done(UART_NUM1, 0);
+    }
+
+    free(data);
+    xSemaphoreGive(*sema);
+    vTaskDelete(NULL);
+}
+
+static void test_task2(void *pvParameters)
+{
+    while (exit_flag == false) {
+        // This task obstruct a setting tx_done_sem semaphore in the UART interrupt.
+        // It leads to waiting the ticks_to_wait time in uart_wait_tx_done() function.
+        uart_disable_intr_mask(UART_NUM1, UART_TX_DONE_INT_ENA_M);
+    }
+    vTaskDelete(NULL);
+}
+
+TEST_CASE("test uart_wait_tx_done is not blocked when ticks_to_wait=0", "[uart]")
+{
+    uart_config(UART_BAUD_11520, false);
+
+    xSemaphoreHandle exit_sema = xSemaphoreCreateBinary();
+    exit_flag = false;
+
+    xTaskCreate(test_task,  "tsk1", 2048, &exit_sema, 5, NULL);
+    xTaskCreate(test_task2, "tsk2", 2048, NULL,       5, NULL);
+
+    printf("Waiting for 5 sec\n");
+    vTaskDelay(5000 / portTICK_PERIOD_MS);
+    exit_flag = true;
+
+    if (xSemaphoreTake(exit_sema, 1000 / portTICK_PERIOD_MS) == pdTRUE) {
+        vSemaphoreDelete(exit_sema);
+    } else {
+        TEST_FAIL_MESSAGE("uart_wait_tx_done is blocked");
+    }
+    TEST_ESP_OK(uart_driver_delete(UART_NUM1));
+}
+
 TEST_CASE("test uart get baud-rate","[uart]")
 {
     uint32_t baud_rate1 = 0;