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>
This commit is contained in:
committed by
Linus Torvalds
parent
b1c931e393
commit
18a8bd949d
@ -15,6 +15,7 @@
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#include <linux/console.h>
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#include <linux/efi.h>
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#include <linux/serial.h>
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#include <linux/serial_8250.h>
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#include <asm/vga.h>
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#include "pcdp.h"
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@ -27,7 +28,7 @@ setup_serial_console(struct pcdp_uart *uart)
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char parity;
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mmio = (uart->addr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY);
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p += sprintf(p, "console=uart,%s,0x%lx",
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p += sprintf(p, "uart8250,%s,0x%lx",
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mmio ? "mmio" : "io", uart->addr.address);
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if (uart->baud) {
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p += sprintf(p, ",%lu", uart->baud);
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@ -41,7 +42,8 @@ setup_serial_console(struct pcdp_uart *uart)
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}
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}
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return early_serial_console_init(options);
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add_preferred_console("uart", 8250, &options[9]);
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return setup_early_serial8250_console(options);
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#else
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return -ENODEV;
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#endif
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