stm32f0: usart: allocate USART console object and expose FILE pointer

include/console.h

@@ -2,4 +2,6 @@
 
 #include <stdio.h>
 
-void console_init(void);
+struct usart_console;
+
+FILE *console_init(void);

source/drivers/usart_console.c

@@ -4,6 +4,7 @@
 #include <libopencm3/cm3/scb.h>
 
 #include <ctype.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -19,12 +20,12 @@
 struct usart_console {
 	char recv_buf[RECV_BUF_LEN];
 	void (* process_line)(void);
+	FILE *fp;
 	volatile size_t cur, next;
 	uint32_t dev;
 };
 
 static struct usart_console *usart[4];
-struct usart_console user_console;
 
 static void usart_isr(struct usart_console *console)
 {
@@ -168,32 +169,30 @@ static int usart_init(struct usart_console *console)
 	return 0;
 }
 
-void console_init(void)
+FILE *console_init(void)
 {
-	cookie_io_functions_t console_in = {
+	cookie_io_functions_t fops = {
 		.read = usart_read,
-		.write = NULL,
-		.seek = NULL,
-		.close = NULL,
-	};
-	cookie_io_functions_t console_out = {
-		.read = NULL,
 		.write = usart_write,
 		.seek = NULL,
 		.close = NULL,
 	};
+	struct usart_console *console;
+
+	if (!(console = malloc(sizeof *console)))
+		return NULL;
+
+	console->dev = USART1;
+	console->cur = 0;
+	console->next = 0;
+	console->process_line = NULL;
+	usart[0] = console;
+
+	usart_init(console);
 
-	user_console.dev = USART1;
-	user_console.cur = 0;
-	user_console.next = 0;
-	usart[0] = &user_console;
-	usart_init(&user_console);
+	console->fp = fopencookie(console, "r+w", fops);
 
-	stdin = fopencookie(&user_console, "r", console_in);
-	stdout = fopencookie(&user_console, "w", console_out);
-	stderr = fopencookie(&user_console, "w", console_out);
+	setbuf(console->fp, NULL);
 
-	setbuf(stdout, NULL);
-	//setlinebuf(stdout);
-	setbuf(stderr, NULL);
+	return console->fp;
 }