tests/periph_uart: add automated test

tests/periph_uart/Kconfig

@@ -10,4 +10,5 @@ config APPLICATION
     default y
     imply MODULE_PERIPH_UART_MODECFG
     imply MODULE_PERIPH_LPUART
+    imply MODULE_PERIPH_UART_RXSTART_IRQ
     depends on TEST_KCONFIG

tests/periph_uart/Makefile

@@ -3,6 +3,7 @@ include ../Makefile.tests_common
 FEATURES_REQUIRED += periph_uart
 FEATURES_OPTIONAL += periph_lpuart  # STM32 L0 and L4 provides lpuart support
 FEATURES_OPTIONAL += periph_uart_modecfg
+FEATURES_OPTIONAL += periph_uart_rxstart_irq
 
 USEMODULE += shell
 USEMODULE += xtimer

tests/periph_uart/main.c

@@ -50,6 +50,10 @@
 #define STDIO_UART_DEV      (UART_UNDEF)
 #endif
 
+#ifndef STX
+#define STX 0x2
+#endif
+
 typedef struct {
     char rx_mem[UART_BUFSIZE];
     ringbuffer_t rx_buf;
@@ -60,6 +64,8 @@ static uart_ctx_t ctx[UART_NUMOF];
 static kernel_pid_t printer_pid;
 static char printer_stack[THREAD_STACKSIZE_MAIN];
 
+static bool test_mode;
+
 #ifdef MODULE_PERIPH_UART_MODECFG
 static uart_data_bits_t data_bits_lut[] = { UART_DATA_BITS_5, UART_DATA_BITS_6,
                                             UART_DATA_BITS_7, UART_DATA_BITS_8 };
@@ -83,18 +89,73 @@ static int parse_dev(char *arg)
     return dev;
 }
 
+#ifdef MODULE_PERIPH_UART_RXSTART_IRQ
+static void rxs_cb(void *arg)
+{
+    ringbuffer_add_one(arg, STX);
+}
+#endif
+
 static void rx_cb(void *arg, uint8_t data)
 {
     uart_t dev = (uart_t)arg;
 
-    ringbuffer_add_one(&(ctx[dev].rx_buf), data);
-    if (data == '\n') {
+    ringbuffer_add_one(&ctx[dev].rx_buf, data);
+
+    if (!test_mode && data == '\n') {
         msg_t msg;
         msg.content.value = (uint32_t)dev;
         msg_send(&msg, printer_pid);
     }
 }
 
+static int _self_test(uart_t dev, unsigned baud)
+{
+    const char test_string[] = "Hello UART!";
+
+    if (uart_init(UART_DEV(dev), baud, rx_cb, (void *)dev)) {
+        printf("error configuring %u baud\n", baud);
+        return -1;
+    }
+
+    test_mode = true;
+
+    uart_write(dev, (uint8_t*)test_string, sizeof(test_string));
+    for (unsigned i = 0; i < sizeof(test_string); ++i) {
+        int c = ringbuffer_get_one(&ctx[dev].rx_buf);
+        if (c != test_string[i]) {
+            printf("mismatch at index %u: %x != %x\n", i, c, test_string[i]);
+            return -1;
+        }
+    }
+
+#ifdef MODULE_PERIPH_UART_RXSTART_IRQ
+    /* test RX Start detection if available */
+    uart_rxstart_irq_configure(dev, rxs_cb, &ctx[dev].rx_buf);
+    uart_rxstart_irq_enable(dev);
+
+    uart_write(dev, (uint8_t*)test_string, sizeof(test_string));
+    for (unsigned i = 0; i < sizeof(test_string); ++i) {
+        int c = ringbuffer_get_one(&ctx[dev].rx_buf);
+        if (c != STX) {
+            printf("expected start condition, got %x\n", c);
+            return -1;
+        }
+
+        c = ringbuffer_get_one(&ctx[dev].rx_buf);
+        if (c != test_string[i]) {
+            printf("mismatch at index %u: %x != %x, start condition reported\n",
+                   i, c, test_string[i]);
+            return -1;
+        }
+    }
+    uart_rxstart_irq_disable(dev);
+#endif
+
+    test_mode = false;
+    return 0;
+}
+
 static void *printer(void *arg)
 {
     (void)arg;
@@ -259,12 +320,41 @@ static int cmd_send(int argc, char **argv)
     return 0;
 }
 
+static int cmd_test(int argc, char **argv)
+{
+    int dev;
+
+    if (argc < 2) {
+        printf("usage: %s <dev>\n", argv[0]);
+        return 1;
+    }
+    /* parse parameters */
+    dev = parse_dev(argv[1]);
+    if (dev < 0) {
+        return 1;
+    }
+
+    puts("[START]");
+
+    /* run self test with different baud rates */
+    for (unsigned i = 1; i <= 12; ++i) {
+        if (_self_test(dev, 9600 * i)) {
+            puts("[FAILURE]");
+            return -1;
+        }
+    }
+
+    puts("[SUCCESS]");
+    return 0;
+}
+
 static const shell_command_t shell_commands[] = {
     { "init", "Initialize a UART device with a given baudrate", cmd_init },
 #ifdef MODULE_PERIPH_UART_MODECFG
     { "mode", "Setup data bits, stop bits and parity for a given UART device", cmd_mode },
 #endif
     { "send", "Send a string through given UART device", cmd_send },
+    { "test", "Run an automated test on a UART with RX and TX connected", cmd_test },
     { NULL, NULL, NULL }
 };