stm32f0: usart: implement asynchronous serial interfaces

include/console.h

@@ -4,6 +4,7 @@
 
 struct usart_console;
 
-typedef void (* process_line_func)(FILE *fp);
-
-FILE *console_init(unsigned dev_id, process_line_func process_line);
+struct usart_console *console_init(unsigned dev_id);
+FILE *console_to_fp(struct usart_console *console);
+int console_getc(char *c, struct usart_console *console);
+int console_getline(struct usart_console *console, char *buf, size_t n);

source/drivers/usart_console.c

@@ -19,46 +19,43 @@
 
 struct usart_console {
 	char recv_buf[RECV_BUF_LEN];
-	void (* process_line)(FILE *fp);
 	FILE *fp;
-	volatile size_t cur, next;
+	volatile size_t cur;
+	volatile size_t next;
+	unsigned irq_no;
 	uint32_t dev;
 };
 
-static struct usart_console *usart[4];
+static struct usart_console usart[4];
 
 static void usart_isr(struct usart_console *console)
 {
-	size_t idx, next;
+	size_t i;
 
 	if (!console)
 		return;
 
 	while (usart_get_flag(console->dev, USART_ISR_RXNE)) {
-		idx = console->next;
-		console->recv_buf[idx] = usart_recv(console->dev);
-
-		next = (console->next + 1) % RECV_BUF_LEN;
-
-		if (next != console->cur)
-			console->next = next;
+		console->recv_buf[console->next] = usart_recv(console->dev);
 
-		if (console->recv_buf[idx] == '\003')
+		if (console->recv_buf[console->next] == '\003')
 			scb_reset_system();
 
-		if (console->recv_buf[idx] == '\r' && console->process_line)
-			console->process_line(console->fp);
+		i = (console->next + 1) % RECV_BUF_LEN;
+
+		if (i != console->cur)
+			console->next = i;
 	}
 }
 
 void usart1_isr(void)
 {
-	usart_isr(usart[0]);
+	usart_isr(usart + 0);
 }
 
 void usart2_isr(void)
 {
-	usart_isr(usart[1]);
+	usart_isr(usart + 1);
 }
 
 static char usart_getc(struct usart_console *console, int block)
@@ -75,6 +72,57 @@ static char usart_getc(struct usart_console *console, int block)
 	return c;
 }
 
+int console_getc(char *c, struct usart_console *console)
+{
+	if (console->cur == console->next)
+		return -1;
+
+	if (console->cur != console->next) {
+		*c = console->recv_buf[console->cur];
+		console->cur = (console->cur + 1) % RECV_BUF_LEN;
+	}
+
+	return 0;
+}
+
+int console_getline(struct usart_console *console, char *buf, size_t n)
+{
+	char *p = buf + strlen(buf);
+	char c;
+
+	*p = '\0';
+
+	while (console_getc(&c, console) == 0) {
+		switch (c) {
+		case '\r':
+			usart_send_blocking(console->dev, '\r');
+			usart_send_blocking(console->dev, '\n');
+			return 0;
+		case 10:
+		case 127:
+			if (buf < p) {
+				usart_send_blocking(console->dev, '\010');
+				usart_send_blocking(console->dev, ' ');
+				usart_send_blocking(console->dev, '\010');
+				--p;
+			}
+
+			break;
+		default:
+			*p = c;
+			usart_send_blocking(console->dev, c);
+
+			if (((size_t)p - (size_t)buf) < n) {
+				++p;
+			}
+		}
+
+		*p = '\0';
+	}
+
+	return -E_AGAIN;
+}
+
 static ssize_t usart_read(void *cookie, char *buf, size_t n)
 {
 	struct usart_console *console = cookie;
@@ -149,9 +197,7 @@ static int usart_get_irq_no(unsigned *irq_no, unsigned dev)
 
 static int usart_init(struct usart_console *console)
 {
-	unsigned irq_no;
-
-	if (usart_get_irq_no(&irq_no, console->dev) < 0)
+	if (usart_get_irq_no(&console->irq_no, console->dev) < 0)
 		return -1;
 
 	usart_set_baudrate(console->dev, 115200);
@@ -161,14 +207,14 @@ static int usart_init(struct usart_console *console)
 	usart_set_mode(console->dev, USART_MODE_TX_RX);
 	usart_set_flow_control(console->dev, USART_FLOWCONTROL_NONE);
 
-	nvic_enable_irq(irq_no);
+	nvic_enable_irq(console->irq_no);
 	usart_enable(console->dev);
 	usart_enable_rx_interrupt(console->dev);
 
 	return 0;
 }
 
-FILE *console_init(unsigned dev_id, void (* process_line)(FILE *fp))
+struct usart_console *console_init(unsigned dev_id)
 {
 	cookie_io_functions_t fops = {
 		.read = usart_read,
@@ -178,8 +224,7 @@ FILE *console_init(unsigned dev_id, void (* process_line)(FILE *fp))
 	};
 	struct usart_console *console;
 
-	if (!(console = malloc(sizeof *console)))
-		return NULL;
+	console = usart + dev_id;
 
 	switch (dev_id) {
 	case 0: console->dev = USART1; break;
@@ -189,8 +234,7 @@ FILE *console_init(unsigned dev_id, void (* process_line)(FILE *fp))
 
 	console->cur = 0;
 	console->next = 0;
-	console->process_line = process_line;
-	usart[dev_id] = console;
+	//usart[dev_id] = console;
 
 	usart_init(console);
 
@@ -198,5 +242,10 @@ FILE *console_init(unsigned dev_id, void (* process_line)(FILE *fp))
 
 	setbuf(console->fp, NULL);
 
+	return console;
+}
+
+FILE *console_to_fp(struct usart_console *console)
+{
 	return console->fp;
 }

source/main.c

@@ -5,13 +5,40 @@
 #include <rcc.h>
 #include <shell.h>
 
+#include <libopencm3/stm32/usart.h>
+
+struct usart_console *user_con, *admin_con;
+FILE *user_io, *admin_io;
+char user_line[128];
+char admin_line[128];
+
 int main(void)
 {
 	rcc_init();
 	gpio_init();
-	console_init();
-	printf("TBM-dev (built on " __DATE__ ")\n");
-	cmd_loop("tbm # ");
+	user_con = console_init(0);
+	admin_con = console_init(1);
+	user_io = console_to_fp(user_con);
+	admin_io = console_to_fp(admin_con);
+
+	fprintf(user_io, "TBM-dev (built on " __DATE__ ")\n");
+	fprintf(admin_io, "TBM-dev (built on " __DATE__ ")\n");
+	fprintf(admin_io, "Welcome to the administrative interface.\n");
+	fprintf(user_io, "tbm # ");
+
+	while (1) {
+		if (console_getline(user_con, user_line, 128) == 0) {
+			fprintf(user_io, "user: %s\n", user_line);
+			fprintf(admin_io, "user: %s\n", user_line);
+			*user_line = '\0';
+		}
+
+		if (console_getline(admin_con, admin_line, 128) == 0) {
+			fprintf(admin_io, "admin: %s\n", admin_line);
+			fprintf(user_io, "admin: %s\n", admin_line);
+			*admin_line = '\0';
+		}
+	}
 
 	return 0;
 }