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 <[e-mail]>
Signed-off-by: Paul Mundt <[e-mail]>

arch/sh/kernel/early_printk.c

···
  * 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

···
 
 	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

···
 	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;
···
 
 	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));
···
 		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;
···
 	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
···
 	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)
···
 	struct plat_sci_port *p = dev->dev.platform_data;
 	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)
···
 	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);