sh-sci: Extend sh-sci driver with early console V2

This is V2 of early serial console support for the sh-sci
driver. The early serial console is using early platform
devices and "earlyprintk". To use this feature the early
platform devices must be broken out to one device per port
and the desired port should be selected on the kernel command
line like: "earlyprintk=sh-sci.N[,baudrate][,keep]"

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/kernel/early_printk.c

@@ -191,15 +191,7 @@ static void scif_sercon_init(char *s)
  * Setup a default console, if more than one is compiled in, rely on the
  * earlyprintk= parsing to give priority.
  */
-static struct console *early_console =
-#ifdef CONFIG_SH_STANDARD_BIOS
-	&bios_console
-#elif defined(CONFIG_EARLY_SCIF_CONSOLE)
-	&scif_console
-#else
-	NULL
-#endif
-	;
+static struct console *early_console;
 
 static int __init setup_early_printk(char *buf)
 {

arch/sh/kernel/setup.c

@@ -423,6 +423,9 @@ void __init setup_arch(char **cmdline_p)
 
 	plat_early_device_setup();
 
+	/* Let earlyprintk output early console messages */
+	early_platform_driver_probe("earlyprintk", 1, 1);
+
 	sh_mv_setup();
 
 	/*

drivers/serial/sh-sci.c

@@ -1043,10 +1043,14 @@ static void __devinit sci_init_single(struct platform_device *dev,
 	sci_port->port.iotype	= UPIO_MEM;
 	sci_port->port.line	= index;
 	sci_port->port.fifosize	= 1;
-	sci_port->iclk		= p->clk ? clk_get(&dev->dev, p->clk) : NULL;
-	sci_port->dclk		= clk_get(&dev->dev, "peripheral_clk");
-	sci_port->enable	= sci_clk_enable;
-	sci_port->disable	= sci_clk_disable;
+
+	if (dev) {
+		sci_port->iclk = p->clk ? clk_get(&dev->dev, p->clk) : NULL;
+		sci_port->dclk = clk_get(&dev->dev, "peripheral_clk");
+		sci_port->enable = sci_clk_enable;
+		sci_port->disable = sci_clk_disable;
+		sci_port->port.dev = &dev->dev;
+	}
 
 	sci_port->break_timer.data = (unsigned long)sci_port;
 	sci_port->break_timer.function = sci_break_timer;
@@ -1057,7 +1061,6 @@ static void __devinit sci_init_single(struct platform_device *dev,
 
 	sci_port->port.irq	= p->irqs[SCIx_TXI_IRQ];
 	sci_port->port.flags	= p->flags;
-	sci_port->port.dev	= &dev->dev;
 	sci_port->type		= sci_port->port.type = p->type;
 
 	memcpy(&sci_port->irqs, &p->irqs, sizeof(p->irqs));
@@ -1101,7 +1104,7 @@ static void serial_console_write(struct console *co, const char *s,
 		sci_port->disable(port);
 }
 
-static int __init serial_console_setup(struct console *co, char *options)
+static int __devinit serial_console_setup(struct console *co, char *options)
 {
 	struct sci_port *sci_port;
 	struct uart_port *port;
@@ -1119,9 +1122,14 @@ static int __init serial_console_setup(struct console *co, char *options)
 	if (co->index >= SCI_NPORTS)
 		co->index = 0;
 
-	sci_port = &sci_ports[co->index];
-	port = &sci_port->port;
-	co->data = port;
+	if (co->data) {
+		port = co->data;
+		sci_port = to_sci_port(port);
+	} else {
+		sci_port = &sci_ports[co->index];
+		port = &sci_port->port;
+		co->data = port;
+	}
 
 	/*
 	 * Also need to check port->type, we don't actually have any
@@ -1165,6 +1173,15 @@ static int __init sci_console_init(void)
 	return 0;
 }
 console_initcall(sci_console_init);
+
+static struct sci_port early_serial_port;
+static struct console early_serial_console = {
+	.name           = "early_ttySC",
+	.write          = serial_console_write,
+	.flags          = CON_PRINTBUFFER,
+};
+static char early_serial_buf[32];
+
 #endif /* CONFIG_SERIAL_SH_SCI_CONSOLE */
 
 #if defined(CONFIG_SERIAL_SH_SCI_CONSOLE)
@@ -1250,6 +1267,21 @@ static int __devinit sci_probe(struct platform_device *dev)
 	struct sh_sci_priv *priv;
 	int i, ret = -EINVAL;
 
+#ifdef CONFIG_SERIAL_SH_SCI_CONSOLE
+	if (is_early_platform_device(dev)) {
+		if (dev->id == -1)
+			return -ENOTSUPP;
+		early_serial_console.index = dev->id;
+		early_serial_console.data = &early_serial_port.port;
+		sci_init_single(NULL, &early_serial_port, dev->id, p);
+		serial_console_setup(&early_serial_console, early_serial_buf);
+		if (!strstr(early_serial_buf, "keep"))
+			early_serial_console.flags |= CON_BOOT;
+		register_console(&early_serial_console);
+		return 0;
+	}
+#endif
+
 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
@@ -1349,6 +1381,10 @@ static void __exit sci_exit(void)
 	uart_unregister_driver(&sci_uart_driver);
 }
 
+#ifdef CONFIG_SERIAL_SH_SCI_CONSOLE
+early_platform_init_buffer("earlyprintk", &sci_driver,
+			   early_serial_buf, ARRAY_SIZE(early_serial_buf));
+#endif
 module_init(sci_init);
 module_exit(sci_exit);