console: Add extensible console matching

Add match() method to struct console which allows the console to
perform console command line matching instead of (or in addition to)
default console matching (ie., by fixed name and index).

The match() method returns 0 to indicate a successful match; normal
console matching occurs if no match() method is defined or the
match() method returns non-zero. The match() method is expected to set
the console index if required.

Re-implement earlycon-to-console-handoff with direct matching of
"console=uart|uart8250,..." to the 8250 ttyS console.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_core.c

@@ -3322,9 +3322,54 @@ static int serial8250_console_setup(struct console *co, char *options)
 	return uart_set_options(port, co, baud, parity, bits, flow);
 }
 
-static int serial8250_console_early_setup(void)
+/**
+ *	serial8250_console_match - non-standard console matching
+ *	@co:	  registering console
+ *	@name:	  name from console command line
+ *	@idx:	  index from console command line
+ *	@options: ptr to option string from console command line
+ *
+ *	Only attempts to match console command lines of the form:
+ *	    console=uart<>,io|mmio|mmio32,<addr>,<options>
+ *	    console=uart<>,<addr>,options
+ *	This form is used to register an initial earlycon boot console and
+ *	replace it with the serial8250_console at 8250 driver init.
+ *
+ *	Performs console setup for a match (as required by interface)
+ *
+ *	Returns 0 if console matches; otherwise non-zero to use default matching
+ */
+static int serial8250_console_match(struct console *co, char *name, int idx,
+				    char *options)
 {
-	return serial8250_find_port_for_earlycon();
+	char match[] = "uart";	/* 8250-specific earlycon name */
+	unsigned char iotype;
+	unsigned long addr;
+	int i;
+
+	if (strncmp(name, match, 4) != 0)
+		return -ENODEV;
+
+	if (uart_parse_earlycon(options, &iotype, &addr, &options))
+		return -ENODEV;
+
+	/* try to match the port specified on the command line */
+	for (i = 0; i < nr_uarts; i++) {
+		struct uart_port *port = &serial8250_ports[i].port;
+
+		if (port->iotype != iotype)
+			continue;
+		if ((iotype == UPIO_MEM || iotype == UPIO_MEM32) &&
+		    (port->mapbase != addr))
+			continue;
+		if (iotype == UPIO_PORT && port->iobase != addr)
+			continue;
+
+		co->index = i;
+		return serial8250_console_setup(co, options);
+	}
+
+	return -ENODEV;
 }
 
 static struct console serial8250_console = {
@@ -3332,7 +3377,7 @@ static struct console serial8250_console = {
 	.write		= serial8250_console_write,
 	.device		= uart_console_device,
 	.setup		= serial8250_console_setup,
-	.early_setup	= serial8250_console_early_setup,
+	.match		= serial8250_console_match,
 	.flags		= CON_PRINTBUFFER | CON_ANYTIME,
 	.index		= -1,
 	.data		= &serial8250_reg,
@@ -3346,19 +3391,6 @@ static int __init serial8250_console_init(void)
 }
 console_initcall(serial8250_console_init);
 
-int serial8250_find_port(struct uart_port *p)
-{
-	int line;
-	struct uart_port *port;
-
-	for (line = 0; line < nr_uarts; line++) {
-		port = &serial8250_ports[line].port;
-		if (uart_match_port(p, port))
-			return line;
-	}
-	return -ENODEV;
-}
-
 #define SERIAL8250_CONSOLE	&serial8250_console
 #else
 #define SERIAL8250_CONSOLE	NULL

drivers/tty/serial/8250/8250_early.c

@@ -173,26 +173,3 @@ int __init setup_early_serial8250_console(char *cmdline)
 
 	return setup_earlycon(cmdline, match, early_serial8250_setup);
 }
-
-int serial8250_find_port_for_earlycon(void)
-{
-	struct earlycon_device *device = early_device;
-	struct uart_port *port = device ? &device->port : NULL;
-	int line;
-	int ret;
-
-	if (!port || (!port->membase && !port->iobase))
-		return -ENODEV;
-
-	line = serial8250_find_port(port);
-	if (line < 0)
-		return -ENODEV;
-
-	ret = update_console_cmdline("uart", 8250,
-			     "ttyS", line, device->options);
-	if (ret < 0)
-		ret = update_console_cmdline("uart", 0,
-				     "ttyS", line, device->options);
-
-	return ret;
-}

include/linux/console.h

@@ -123,7 +123,7 @@ struct console {
 	struct tty_driver *(*device)(struct console *, int *);
 	void	(*unblank)(void);
 	int	(*setup)(struct console *, char *);
-	int	(*early_setup)(void);
+	int	(*match)(struct console *, char *name, int idx, char *options);
 	short	flags;
 	short	index;
 	int	cflag;
@@ -141,7 +141,6 @@ extern int console_set_on_cmdline;
 extern struct console *early_console;
 
 extern int add_preferred_console(char *name, int idx, char *options);
-extern int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options);
 extern void register_console(struct console *);
 extern int unregister_console(struct console *);
 extern struct console *console_drivers;

include/linux/serial_8250.h

@@ -118,8 +118,6 @@ void serial8250_resume_port(int line);
 
 extern int early_serial_setup(struct uart_port *port);
 
-extern int serial8250_find_port(struct uart_port *p);
-extern int serial8250_find_port_for_earlycon(void);
 extern unsigned int serial8250_early_in(struct uart_port *port, int offset);
 extern void serial8250_early_out(struct uart_port *port, int offset, int value);
 extern int setup_early_serial8250_console(char *cmdline);

kernel/printk/printk.c

@@ -2017,24 +2017,6 @@ int add_preferred_console(char *name, int idx, char *options)
 	return __add_preferred_console(name, idx, options, NULL);
 }
 
-int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options)
-{
-	struct console_cmdline *c;
-	int i;
-
-	for (i = 0, c = console_cmdline;
-	     i < MAX_CMDLINECONSOLES && c->name[0];
-	     i++, c++)
-		if (strcmp(c->name, name) == 0 && c->index == idx) {
-			strlcpy(c->name, name_new, sizeof(c->name));
-			c->options = options;
-			c->index = idx_new;
-			return i;
-		}
-	/* not found */
-	return -1;
-}
-
 bool console_suspend_enabled = true;
 EXPORT_SYMBOL(console_suspend_enabled);
 
@@ -2436,9 +2418,6 @@ void register_console(struct console *newcon)
 	if (preferred_console < 0 || bcon || !console_drivers)
 		preferred_console = selected_console;
 
-	if (newcon->early_setup)
-		newcon->early_setup();
-
 	/*
 	 *	See if we want to use this console driver. If we
 	 *	didn't select a console we take the first one
@@ -2464,6 +2443,9 @@ void register_console(struct console *newcon)
 	for (i = 0, c = console_cmdline;
 	     i < MAX_CMDLINECONSOLES && c->name[0];
 	     i++, c++) {
+		if (!newcon->match ||
+		    newcon->match(newcon, c->name, c->index, c->options) != 0) {
+			/* default matching */
 			BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name));
 			if (strcmp(c->name, newcon->name) != 0)
 				continue;
@@ -2477,8 +2459,10 @@ void register_console(struct console *newcon)
 				return;
 
 			if (newcon->setup &&
-		    newcon->setup(newcon, console_cmdline[i].options) != 0)
+			    newcon->setup(newcon, c->options) != 0)
 				break;
+		}
+
 		newcon->flags |= CON_ENABLED;
 		if (i == selected_console) {
 			newcon->flags |= CON_CONSDEV;