[MIPS] Add early console for Cobalt.

Signed-off-by: Peter Horton <pdh@colonel-panic.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -790,6 +790,7 @@ source "arch/mips/tx4927/Kconfig"
 source "arch/mips/tx4938/Kconfig"
 source "arch/mips/vr41xx/Kconfig"
 source "arch/mips/philips/pnx8550/common/Kconfig"
+source "arch/mips/cobalt/Kconfig"
 
 endmenu
 

arch/mips/cobalt/Kconfig

+config EARLY_PRINTK
+	bool "Early console support"
+	depends on MIPS_COBALT
+	help
+	  Provide early console support by direct access to the
+	  on board UART. The UART must have been previously
+	  initialised by the boot loader.

arch/mips/cobalt/Makefile

@@ -4,4 +4,6 @@
 
 obj-y	 := irq.o int-handler.o reset.o setup.o
 
+obj-$(CONFIG_EARLY_PRINTK)	+= console.o
+
 EXTRA_AFLAGS := $(CFLAGS)

arch/mips/cobalt/console.c

+/*
+ * (C) P. Horton 2006
+ */
+
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/console.h>
+#include <linux/serial_reg.h>
+#include <asm/addrspace.h>
+#include <asm/mach-cobalt/cobalt.h>
+
+static void putchar(int c)
+{
+	if(c == '\n')
+		putchar('\r');
+
+	while(!(COBALT_UART[UART_LSR] & UART_LSR_THRE))
+		;
+
+	COBALT_UART[UART_TX] = c;
+}
+
+static void cons_write(struct console *c, const char *s, unsigned n)
+{
+	while(n-- && *s)
+		putchar(*s++);
+}
+
+static struct console cons_info =
+{
+	.name	= "uart",
+	.write	= cons_write,
+	.flags	= CON_PRINTBUFFER | CON_BOOT,
+	.index	= -1,
+};
+
+void __init cobalt_early_console(void)
+{
+	register_console(&cons_info);
+
+	printk("Cobalt: early console registered\n");
+}

arch/mips/cobalt/setup.c

@@ -31,6 +31,7 @@
 extern void cobalt_machine_restart(char *command);
 extern void cobalt_machine_halt(void);
 extern void cobalt_machine_power_off(void);
+extern void cobalt_early_console(void);
 
 int cobalt_board_id;
 
@@ -109,14 +110,6 @@ void __init plat_setup(void)
 	/* I/O port resource must include UART and LCD/buttons */
 	ioport_resource.end = 0x0fffffff;
 
-	/*
-	 * This is a prom style console. We just poke at the
-	 *  UART to make it talk.
-	 * Only use this console if you really screw up and can't
-	 *  get to the stage of setting up a real serial console.
-	 */
-	/*ns16550_setup_console();*/
-
 	/* request I/O space for devices used on all i[345]86 PCs */
 	for (i = 0; i < COBALT_IO_RESOURCES; i++)
 		request_resource(&ioport_resource, cobalt_io_resources + i);
@@ -136,6 +129,10 @@ void __init plat_setup(void)
 #ifdef CONFIG_SERIAL_8250
 	if (cobalt_board_id > COBALT_BRD_ID_RAQ1) {
 
+#ifdef CONFIG_EARLY_PRINTK
+		cobalt_early_console();
+#endif
+
 		uart.line	= 0;
 		uart.type	= PORT_UNKNOWN;
 		uart.uartclk	= 18432000;

include/asm-mips/mach-cobalt/cobalt.h

@@ -113,4 +113,6 @@ do {									\
 # define COBALT_KEY_SELECT	(1 << 7)
 # define COBALT_KEY_MASK	0xfe
 
+#define COBALT_UART		((volatile unsigned char *) CKSEG1ADDR(0x1c800000))
+
 #endif /* __ASM_COBALT_H */