serial: convert early_uart to earlycon for 8250

Beacuse SERIAL_PORT_DFNS is removed from include/asm-i386/serial.h and
include/asm-x86_64/serial.h.  the serial8250_ports need to be probed late in
serial initializing stage.  the console_init=>serial8250_console_init=>
register_console=>serial8250_console_setup will return -ENDEV, and console
ttyS0 can not be enabled at that time.  need to wait till uart_add_one_port in
drivers/serial/serial_core.c to call register_console to get console ttyS0.
that is too late.

Make early_uart to use early_param, so uart console can be used earlier.  Make
it to be bootconsole with CON_BOOT flag, so can use console handover feature.
and it will switch to corresponding normal serial console automatically.

new command line will be:
	console=uart8250,io,0x3f8,9600n8
	console=uart8250,mmio,0xff5e0000,115200n8
or
	earlycon=uart8250,io,0x3f8,9600n8
	earlycon=uart8250,mmio,0xff5e0000,115200n8

it will print in very early stage:
	Early serial console at I/O port 0x3f8 (options '9600n8')
	console [uart0] enabled
later for console it will print:
	console handover: boot [uart0] -> real [ttyS0]

Signed-off-by: <yinghai.lu@sun.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

7 files changed, 13 insertions, 7 deletions

diff --git a/include/asm-i386/fixmap.h b/include/asm-i386/fixmap.h
index 80ea052ee3a4..249e753ac805 100644
--- a/include/asm-i386/fixmap.h
+++ b/include/asm-i386/fixmap.h
@@ -54,6 +54,8 @@ extern unsigned long __FIXADDR_TOP;
 enum fixed_addresses {
         FIX_HOLE,
         FIX_VDSO,
+        FIX_DBGP_BASE,
+        FIX_EARLYCON_MEM_BASE,
 #ifdef CONFIG_X86_LOCAL_APIC
         FIX_APIC_BASE,  /* local (CPU) APIC) -- required for SMP or not */
 #endif
diff --git a/include/asm-i386/io.h b/include/asm-i386/io.h
index e797586a5bfc..7b65b5b00034 100644
--- a/include/asm-i386/io.h
+++ b/include/asm-i386/io.h
@@ -129,6 +129,7 @@ extern void iounmap(volatile void __iomem *addr);
  */
 extern void *bt_ioremap(unsigned long offset, unsigned long size);
 extern void bt_iounmap(void *addr, unsigned long size);
+extern void __iomem *fix_ioremap(unsigned idx, unsigned long phys);
 
 /* Use early IO mappings for DMI because it's initialized early */
 #define dmi_ioremap bt_ioremap
diff --git a/include/asm-x86_64/fixmap.h b/include/asm-x86_64/fixmap.h
index e90e1677531b..2acb9b7f6418 100644
--- a/include/asm-x86_64/fixmap.h
+++ b/include/asm-x86_64/fixmap.h
@@ -35,6 +35,8 @@ enum fixed_addresses {
         VSYSCALL_LAST_PAGE,
         VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE + ((VSYSCALL_END-VSYSCALL_START) >> PAGE_SHIFT) - 1,
         VSYSCALL_HPET,
+        FIX_DBGP_BASE,
+        FIX_EARLYCON_MEM_BASE,
         FIX_HPET_BASE,
         FIX_APIC_BASE,  /* local (CPU) APIC) -- required for SMP or not */
         FIX_IO_APIC_BASE_0,
@@ -84,7 +86,7 @@ static __always_inline unsigned long fix_to_virt(const unsigned int idx)
         if (idx >= __end_of_fixed_addresses)
                 __this_fixmap_does_not_exist();
 
-        return __fix_to_virt(idx);
+        return __fix_to_virt(idx);
 }
 
 #endif
diff --git a/include/asm-x86_64/io.h b/include/asm-x86_64/io.h
index de2cd9a2303a..7475095c5061 100644
--- a/include/asm-x86_64/io.h
+++ b/include/asm-x86_64/io.h
@@ -144,6 +144,7 @@ extern void early_iounmap(void *addr, unsigned long size);
  */
 extern void __iomem * ioremap_nocache (unsigned long offset, unsigned long size);
 extern void iounmap(volatile void __iomem *addr);
+extern void __iomem *fix_ioremap(unsigned idx, unsigned long phys);
 
 /*
  * ISA I/O bus memory addresses are 1:1 with the physical address.
diff --git a/include/linux/console.h b/include/linux/console.h
index 62ef6e11d0d2..c44d3dfde7a5 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -99,6 +99,7 @@ struct console {
         struct tty_driver *(*device)(struct console *, int *);
         void    (*unblank)(void);
         int     (*setup)(struct console *, char *);
+        int     (*early_setup)(void);
         short   flags;
         short   index;
         int     cflag;
@@ -107,6 +108,7 @@ struct 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;
diff --git a/include/linux/serial.h b/include/linux/serial.h
index 33fc8cb8ddfb..deb714314fb1 100644
--- a/include/linux/serial.h
+++ b/include/linux/serial.h
@@ -177,11 +177,5 @@ struct serial_icounter_struct {
 #ifdef __KERNEL__
 #include <linux/compiler.h>
 
-/* Allow architectures to override entries in serial8250_ports[] at run time: */
-struct uart_port;       /* forward declaration */
-extern int early_serial_setup(struct uart_port *port);
-extern int early_serial_console_init(char *options);
-extern int serial8250_start_console(struct uart_port *port, char *options);
-
 #endif /* __KERNEL__ */
 #endif /* _LINUX_SERIAL_H */
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index 71310d80c09a..706ee9a4c80c 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -60,4 +60,8 @@ void serial8250_unregister_port(int line);
 void serial8250_suspend_port(int line);
 void serial8250_resume_port(int line);
 
+extern int serial8250_find_port(struct uart_port *p);
+extern int serial8250_find_port_for_earlycon(void);
+extern int setup_early_serial8250_console(char *cmdline);
+
 #endif