serial: uart_native_pty: IRQ support

Add support for the interrupt-driven API. Interrupts are
emulated using a polling thread.

Signed-off-by: Tim Pambor <tim.pambor@codewrights.de>

Author: tpambor

boards/native/native_sim/doc/index.rst

@@ -564,8 +564,7 @@ program ends, one could do:
 
    $ zephyr.exe --uart_attach_uart_cmd='ln -s %s /tmp/somename' ; rm /tmp/somename
 
-This driver supports poll mode or async mode with :kconfig:option:`CONFIG_UART_ASYNC_API`.
-Interrupt mode is not supported.
+This driver supports poll mode, interrupt mode and async mode.
 Neither runtime configuration or line control are supported.
 
 .. _native_tty_uart:

drivers/serial/Kconfig.native_pty

@@ -7,6 +7,7 @@ config UART_NATIVE_PTY
 	depends on (DT_HAS_ZEPHYR_NATIVE_PTY_UART_ENABLED || DT_HAS_ZEPHYR_NATIVE_POSIX_UART_ENABLED)
 	select SERIAL_HAS_DRIVER
 	select SERIAL_SUPPORT_ASYNC
+	select SERIAL_SUPPORT_INTERRUPT
 	help
 	  This enables a PTY based UART driver for the POSIX ARCH with up to 2 UARTs.
 	  For the first UART port, the driver can be configured

drivers/serial/uart_native_pty.c

@@ -43,6 +43,7 @@ struct native_pty_status {
 	int out_fd;       /* File descriptor used for output */
 	int in_fd;        /* File descriptor used for input */
 	bool on_stdinout; /* This UART is connected to a PTY and not STDIN/OUT */
+	bool stdin_disconnected;
 
 	bool auto_attach;      /* For PTY, attach a terminal emulator automatically */
 	char *auto_attach_cmd; /* If auto_attach, which command to launch the terminal emulator */
@@ -64,6 +65,18 @@ struct native_pty_status {
 		K_KERNEL_STACK_MEMBER(rx_stack, CONFIG_ARCH_POSIX_RECOMMENDED_STACK_SIZE);
 	} async;
 #endif /* CONFIG_UART_ASYNC_API */
+#ifdef CONFIG_UART_INTERRUPT_DRIVEN
+	struct {
+		bool tx_enabled;
+		bool rx_enabled;
+		uart_irq_callback_user_data_t callback;
+		void *cb_data;
+		/* Instance-specific IRQ emulation thread. */
+		struct k_thread poll_thread;
+		/* Stack for IRQ emulation thread */
+		K_KERNEL_STACK_MEMBER(poll_stack, CONFIG_ARCH_POSIX_RECOMMENDED_STACK_SIZE);
+	} irq;
+#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
 };
 
 static void np_uart_poll_out(const struct device *dev, unsigned char out_char);
@@ -81,6 +94,22 @@ static int np_uart_rx_enable(const struct device *dev, uint8_t *buf, size_t len,
 static int np_uart_rx_disable(const struct device *dev);
 #endif /* CONFIG_UART_ASYNC_API */
 
+#ifdef CONFIG_UART_INTERRUPT_DRIVEN
+static int np_uart_fifo_fill(const struct device *dev, const uint8_t *tx_data, int size);
+static int np_uart_fifo_read(const struct device *dev, uint8_t *rx_data, const int size);
+static void np_uart_irq_tx_enable(const struct device *dev);
+static void np_uart_irq_tx_disable(const struct device *dev);
+static int np_uart_irq_tx_ready(const struct device *dev);
+static int np_uart_irq_tx_complete(const struct device *dev);
+static void np_uart_irq_rx_enable(const struct device *dev);
+static void np_uart_irq_rx_disable(const struct device *dev);
+static int np_uart_irq_rx_ready(const struct device *dev);
+static int np_uart_irq_is_pending(const struct device *dev);
+static int np_uart_irq_update(const struct device *dev);
+static void np_uart_irq_callback_set(const struct device *dev, uart_irq_callback_user_data_t cb,
+				     void *cb_data);
+#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
+
 static DEVICE_API(uart, np_uart_driver_api) = {
 	.poll_out = np_uart_poll_out,
 	.poll_in = np_uart_poll_in,
@@ -92,6 +121,20 @@ static DEVICE_API(uart, np_uart_driver_api) = {
 	.rx_enable = np_uart_rx_enable,
 	.rx_disable = np_uart_rx_disable,
 #endif /* CONFIG_UART_ASYNC_API */
+#ifdef CONFIG_UART_INTERRUPT_DRIVEN
+	.fifo_fill        = np_uart_fifo_fill,
+	.fifo_read        = np_uart_fifo_read,
+	.irq_tx_enable    = np_uart_irq_tx_enable,
+	.irq_tx_disable	  = np_uart_irq_tx_disable,
+	.irq_tx_ready     = np_uart_irq_tx_ready,
+	.irq_tx_complete  = np_uart_irq_tx_complete,
+	.irq_rx_enable    = np_uart_irq_rx_enable,
+	.irq_rx_disable   = np_uart_irq_rx_disable,
+	.irq_rx_ready     = np_uart_irq_rx_ready,
+	.irq_is_pending   = np_uart_irq_is_pending,
+	.irq_update       = np_uart_irq_update,
+	.irq_callback_set = np_uart_irq_callback_set,
+#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
 };
 
 #define NATIVE_PTY_INSTANCE(inst)                                        \
@@ -192,61 +235,49 @@ static void np_uart_poll_out(const struct device *dev, unsigned char out_char)
 }
 
 /**
- * @brief Poll the device for input.
+ * @brief Poll the device for up to len input characters
  *
  * @param dev UART device structure.
  * @param p_char Pointer to character.
  *
- * @retval 0 If a character arrived and was stored in p_char
+ * @retval > 0 If a character arrived and was stored in p_char
+ * @retval == 0 If a character arrived but len was 0
  * @retval -1 If no character was available to read
  */
-static int np_uart_stdin_poll_in(const struct device *dev, unsigned char *p_char)
+static int np_uart_poll_in_n(const struct device *dev, unsigned char *p_char, int len)
 {
-	int in_f = ((struct native_pty_status *)dev->data)->in_fd;
-	static bool disconnected;
-	int rc;
+	int rc = -1;
+	struct native_pty_status *data = (struct native_pty_status *)dev->data;
+	int in_f = data->in_fd;
 
-	if (disconnected == true) {
+	if (data->stdin_disconnected) {
 		return -1;
 	}
 
-	rc = np_uart_stdin_poll_in_bottom(in_f, p_char, 1);
-	if (rc == -2) {
-		disconnected = true;
+	if (data->on_stdinout) {
+		rc = np_uart_stdin_poll_in_bottom(in_f, p_char, len);
+
+		if (rc == -2) {
+			data->stdin_disconnected = true;
+			return -1;
+		}
+	} else {
+		rc = np_uart_pty_poll_in_bottom(in_f, p_char, len);
 	}
-	return rc == 1 ? 0 : -1;
+
+	return rc;
 }
 
-/**
- * @brief Poll the device for input.
- *
- * @param dev UART device structure.
- * @param p_char Pointer to character.
- *
- * @retval 0 If a character arrived and was stored in p_char
- * @retval -1 If no character was available to read
- */
-static int np_uart_pty_poll_in(const struct device *dev, unsigned char *p_char)
+static int np_uart_poll_in(const struct device *dev, unsigned char *p_char)
 {
-	int n = -1;
-	int in_f = ((struct native_pty_status *)dev->data)->in_fd;
+	int ret = np_uart_poll_in_n(dev, p_char, 1);
 
-	n = nsi_host_read(in_f, p_char, 1);
-	if (n == -1) {
+	if (ret == -1) {
 		return -1;
 	}
 	return 0;
 }
 
-static int np_uart_poll_in(const struct device *dev, unsigned char *p_char)
-{
-	if (((struct native_pty_status *)dev->data)->on_stdinout) {
-		return np_uart_stdin_poll_in(dev, p_char);
-	} else {
-		return np_uart_pty_poll_in(dev, p_char);
-	}
-}
-
 #ifdef CONFIG_UART_ASYNC_API
 
 static int np_uart_callback_set(const struct device *dev, uart_callback_t callback, void *user_data)
@@ -337,8 +368,7 @@ static void native_pty_uart_async_poll_function(void *arg1, void *arg2, void *ar
 	ARG_UNUSED(arg3);
 
 	while (data->async.rx_len) {
-		rc = np_uart_stdin_poll_in_bottom(data->in_fd, data->async.rx_buf,
-						  data->async.rx_len);
+		rc = np_uart_poll_in_n(dev, data->async.rx_buf, data->async.rx_len);
 		if (rc > 0) {
 			/* Data received */
 			evt.type = UART_RX_RDY;
@@ -403,6 +433,179 @@ static int np_uart_rx_disable(const struct device *dev)
 
 #endif /* CONFIG_UART_ASYNC_API */
 
+#ifdef CONFIG_UART_INTERRUPT_DRIVEN
+static void np_uart_irq_handler(const struct device *dev)
+{
+	struct native_pty_status *data = dev->data;
+
+	if (data->irq.callback) {
+		data->irq.callback(dev, data->irq.cb_data);
+	} else {
+		WARN("No callback!\n");
+	}
+}
+
+/*
+ * Emulate uart interrupts using a polling thread
+ */
+static void np_uart_irq_thread(void *arg1, void *arg2, void *arg3)
+{
+	ARG_UNUSED(arg2);
+	ARG_UNUSED(arg3);
+
+	struct device *dev = (struct device *)arg1;
+	struct native_pty_status *data = dev->data;
+
+	while (1) {
+		if (data->irq.rx_enabled) {
+			int ret = np_uart_poll_in_n(dev, NULL, 0);
+
+			if (ret == 0) {
+				np_uart_irq_handler(dev);
+			} else if (ret == -1) {
+				k_sleep(K_MSEC(1));
+			} else {
+				WARN("Poll returned error %d\n", ret);
+			}
+		}
+		if (data->irq.tx_enabled) {
+			np_uart_irq_handler(dev);
+		}
+		if (!data->irq.tx_enabled && !data->irq.rx_enabled) {
+			break; /* No IRQs enabled, exit the thread */
+		}
+	}
+}
+
+static void np_uart_irq_thread_start(const struct device *dev)
+{
+	struct native_pty_status *data = dev->data;
+
+	/* Create a thread which will wait for data - replacement for IRQ */
+	k_thread_create(&data->irq.poll_thread, data->irq.poll_stack,
+			K_KERNEL_STACK_SIZEOF(data->irq.poll_stack),
+			np_uart_irq_thread,
+			(void *)dev, NULL, NULL,
+			K_HIGHEST_THREAD_PRIO, 0, K_NO_WAIT);
+}
+
+static void np_uart_irq_thread_stop(const struct device *dev)
+{
+	struct native_pty_status *data = dev->data;
+
+	/* Wait for IRQ thread to terminate */
+	k_thread_join(&data->irq.poll_thread, K_FOREVER);
+}
+
+static int np_uart_fifo_fill(const struct device *dev, const uint8_t *tx_data, int size)
+{
+	for (int i = 0; i < size; i++) {
+		np_uart_poll_out(dev, tx_data[i]);
+	}
+
+	return size;
+}
+
+static int np_uart_fifo_read(const struct device *dev, uint8_t *rx_data, const int size)
+{
+	return np_uart_poll_in_n(dev, rx_data, size);
+}
+
+static int np_uart_irq_tx_ready(const struct device *dev)
+{
+	struct native_pty_status *data = dev->data;
+
+	return data->irq.tx_enabled ? 1 : 0;
+}
+
+static int np_uart_irq_tx_complete(const struct device *dev)
+{
+	ARG_UNUSED(dev);
+
+	return 1;
+}
+
+static void np_uart_irq_tx_enable(const struct device *dev)
+{
+	struct native_pty_status *data = dev->data;
+
+	bool start_thread = !data->irq.rx_enabled && !data->irq.tx_enabled;
+
+	data->irq.tx_enabled = true;
+
+	if (start_thread) {
+		np_uart_irq_thread_start(dev);
+	}
+}
+
+static void np_uart_irq_tx_disable(const struct device *dev)
+{
+	struct native_pty_status *data = dev->data;
+
+	data->irq.tx_enabled = false;
+
+	if (!data->irq.rx_enabled && !data->irq.tx_enabled) {
+		np_uart_irq_thread_stop(dev);
+	}
+}
+
+static void np_uart_irq_rx_enable(const struct device *dev)
+{
+	struct native_pty_status *data = dev->data;
+
+	bool start_thread = !data->irq.rx_enabled && !data->irq.tx_enabled;
+
+	data->irq.rx_enabled = true;
+
+	if (start_thread) {
+		np_uart_irq_thread_start(dev);
+	}
+}
+
+static void np_uart_irq_rx_disable(const struct device *dev)
+{
+	struct native_pty_status *data = dev->data;
+
+	data->irq.rx_enabled = false;
+
+	if (!data->irq.rx_enabled && !data->irq.tx_enabled) {
+		np_uart_irq_thread_stop(dev);
+	}
+}
+
+static int np_uart_irq_rx_ready(const struct device *dev)
+{
+	struct native_pty_status *data = dev->data;
+
+	if (data->irq.rx_enabled && np_uart_poll_in_n(dev, NULL, 0) == 0) {
+		return 1;
+	}
+	return 0;
+}
+
+static int np_uart_irq_is_pending(const struct device *dev)
+{
+	return np_uart_irq_rx_ready(dev) ||
+		np_uart_irq_tx_ready(dev);
+}
+
+static int np_uart_irq_update(const struct device *dev)
+{
+	ARG_UNUSED(dev);
+
+	return 1;
+}
+
+static void np_uart_irq_callback_set(const struct device *dev, uart_irq_callback_user_data_t cb,
+				     void *cb_data)
+{
+	struct native_pty_status *data = dev->data;
+
+	data->irq.callback = cb;
+	data->irq.cb_data = cb_data;
+}
+#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
+
 
 #define NATIVE_PTY_SET_AUTO_ATTACH_CMD(inst, cmd)      \
 	native_pty_status_##inst.auto_attach_cmd = cmd;