drivers: uart: uart_native_tty: allow multiple instances

Adds one RX thread per instance. Previously, only one global RX thread was
used resulting in crashes due to the thread instance being overwritten by
other instances.

Signed-off-by: Nils Ruf <nils.ruf@endress.com>

Author: NilsRuf-EH

drivers/serial/uart_native_tty.c

@@ -48,6 +48,10 @@ struct native_tty_data {
 	uart_irq_callback_user_data_t callback;
 	/* IRQ callback data */
 	void *cb_data;
+	/* Instance-specific RX thread. */
+	struct k_thread rx_thread;
+	/* RX thread stack. */
+	K_KERNEL_STACK_MEMBER(rx_stack, CONFIG_ARCH_POSIX_RECOMMENDED_STACK_SIZE);
 #endif
 };
 
@@ -56,8 +60,6 @@ struct native_tty_config {
 };
 
 #ifdef CONFIG_UART_INTERRUPT_DRIVEN
-static struct k_thread rx_thread;
-static K_KERNEL_STACK_DEFINE(rx_stack, CONFIG_ARCH_POSIX_RECOMMENDED_STACK_SIZE);
 #define NATIVE_TTY_INIT_LEVEL POST_KERNEL
 #else
 #define NATIVE_TTY_INIT_LEVEL PRE_KERNEL_1
@@ -311,8 +313,10 @@ static void native_tty_uart_irq_callback_set(const struct device *dev,
 
 static void native_tty_irq_init(const struct device *dev)
 {
+	struct native_tty_data *data = dev->data;
+
 	/* Create a thread which will wait for data - replacement for IRQ */
-	k_thread_create(&rx_thread, rx_stack, K_KERNEL_STACK_SIZEOF(rx_stack),
+	k_thread_create(&data->rx_thread, data->rx_stack, K_KERNEL_STACK_SIZEOF(data->rx_stack),
 			native_tty_uart_irq_function,
 			(void *)dev, NULL, NULL,
 			K_HIGHEST_THREAD_PRIO, 0, K_NO_WAIT);