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https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git
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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: <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Bjorn Helgaas <[email protected]> Cc: Russell King <[email protected]> Cc: Gerd Hoffmann <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Yinghai Lu
Linus Torvalds
parent
b1c931e393
commit
18a8bd949d
15 changed files with 132 additions and 95 deletions
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@ -2514,12 +2514,18 @@ static int __init serial8250_console_setup(struct console *co, char *options)
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return uart_set_options(port, co, baud, parity, bits, flow);
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}
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static int __init serial8250_console_early_setup(void)
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{
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return serial8250_find_port_for_earlycon();
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}
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static struct uart_driver serial8250_reg;
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static struct console serial8250_console = {
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.name = "ttyS",
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.write = serial8250_console_write,
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.device = uart_console_device,
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.setup = serial8250_console_setup,
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.early_setup = serial8250_console_early_setup,
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.flags = CON_PRINTBUFFER,
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.index = -1,
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.data = &serial8250_reg,
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@ -2533,7 +2539,7 @@ static int __init serial8250_console_init(void)
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}
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console_initcall(serial8250_console_init);
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static int __init find_port(struct uart_port *p)
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int serial8250_find_port(struct uart_port *p)
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{
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int line;
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struct uart_port *port;
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@ -2546,26 +2552,6 @@ static int __init find_port(struct uart_port *p)
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return -ENODEV;
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}
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int __init serial8250_start_console(struct uart_port *port, char *options)
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{
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int line;
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line = find_port(port);
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if (line < 0)
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return -ENODEV;
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add_preferred_console("ttyS", line, options);
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printk("Adding console on ttyS%d at %s 0x%lx (options '%s')\n",
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line, port->iotype == UPIO_MEM ? "MMIO" : "I/O port",
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port->iotype == UPIO_MEM ? (unsigned long) port->mapbase :
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(unsigned long) port->iobase, options);
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if (!(serial8250_console.flags & CON_ENABLED)) {
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serial8250_console.flags &= ~CON_PRINTBUFFER;
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register_console(&serial8250_console);
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}
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return line;
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}
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#define SERIAL8250_CONSOLE &serial8250_console
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#else
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#define SERIAL8250_CONSOLE NULL
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@ -17,13 +17,11 @@
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* we locate the device directly by its MMIO or I/O port address.
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*
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* The user can specify the device directly, e.g.,
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* console=uart,io,0x3f8,9600n8
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* console=uart,mmio,0xff5e0000,115200n8
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* or platform code can call early_uart_console_init() to set
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* the early UART device.
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*
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* After the normal serial driver starts, we try to locate the
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* matching ttyS device and start a console there.
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* earlycon=uart8250,io,0x3f8,9600n8
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* earlycon=uart8250,mmio,0xff5e0000,115200n8
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* or
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* console=uart8250,io,0x3f8,9600n8
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* console=uart8250,mmio,0xff5e0000,115200n8
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*/
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#include <linux/tty.h>
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@ -32,17 +30,21 @@
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#include <linux/serial_core.h>
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#include <linux/serial_reg.h>
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#include <linux/serial.h>
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#include <linux/serial_8250.h>
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#include <asm/io.h>
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#include <asm/serial.h>
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#ifdef CONFIG_FIX_EARLYCON_MEM
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#include <asm/pgtable.h>
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#include <asm/fixmap.h>
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#endif
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struct early_uart_device {
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struct early_serial8250_device {
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struct uart_port port;
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char options[16]; /* e.g., 115200n8 */
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unsigned int baud;
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};
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static struct early_uart_device early_device __initdata;
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static int early_uart_registered __initdata;
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static struct early_serial8250_device early_device;
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static unsigned int __init serial_in(struct uart_port *port, int offset)
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{
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@ -80,7 +82,7 @@ static void __init putc(struct uart_port *port, int c)
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serial_out(port, UART_TX, c);
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}
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static void __init early_uart_write(struct console *console, const char *s, unsigned int count)
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static void __init early_serial8250_write(struct console *console, const char *s, unsigned int count)
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{
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struct uart_port *port = &early_device.port;
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unsigned int ier;
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@ -111,7 +113,7 @@ static unsigned int __init probe_baud(struct uart_port *port)
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return (port->uartclk / 16) / quot;
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}
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static void __init init_port(struct early_uart_device *device)
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static void __init init_port(struct early_serial8250_device *device)
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{
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struct uart_port *port = &device->port;
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unsigned int divisor;
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@ -130,10 +132,9 @@ static void __init init_port(struct early_uart_device *device)
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serial_out(port, UART_LCR, c & ~UART_LCR_DLAB);
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}
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static int __init parse_options(struct early_uart_device *device, char *options)
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static int __init parse_options(struct early_serial8250_device *device, char *options)
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{
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struct uart_port *port = &device->port;
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int mapsize = 64;
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int mmio, length;
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if (!options)
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@ -143,12 +144,18 @@ static int __init parse_options(struct early_uart_device *device, char *options)
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if (!strncmp(options, "mmio,", 5)) {
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port->iotype = UPIO_MEM;
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port->mapbase = simple_strtoul(options + 5, &options, 0);
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port->membase = ioremap(port->mapbase, mapsize);
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#ifdef CONFIG_FIX_EARLYCON_MEM
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set_fixmap_nocache(FIX_EARLYCON_MEM_BASE, port->mapbase & PAGE_MASK);
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port->membase = (void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE);
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port->membase += port->mapbase & ~PAGE_MASK;
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#else
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port->membase = ioremap(port->mapbase, 64);
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if (!port->membase) {
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printk(KERN_ERR "%s: Couldn't ioremap 0x%lx\n",
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__FUNCTION__, port->mapbase);
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return -ENOMEM;
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}
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#endif
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mmio = 1;
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} else if (!strncmp(options, "io,", 3)) {
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port->iotype = UPIO_PORT;
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@ -175,9 +182,16 @@ static int __init parse_options(struct early_uart_device *device, char *options)
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return 0;
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}
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static int __init early_uart_setup(struct console *console, char *options)
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static struct console early_serial8250_console __initdata = {
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.name = "uart",
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.write = early_serial8250_write,
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.flags = CON_PRINTBUFFER | CON_BOOT,
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.index = -1,
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};
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static int __init early_serial8250_setup(char *options)
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{
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struct early_uart_device *device = &early_device;
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struct early_serial8250_device *device = &early_device;
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int err;
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if (device->port.membase || device->port.iobase)
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@ -190,61 +204,48 @@ static int __init early_uart_setup(struct console *console, char *options)
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return 0;
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}
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static struct console early_uart_console __initdata = {
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.name = "uart",
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.write = early_uart_write,
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.setup = early_uart_setup,
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.flags = CON_PRINTBUFFER,
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.index = -1,
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};
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static int __init early_uart_console_init(void)
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{
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if (!early_uart_registered) {
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register_console(&early_uart_console);
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early_uart_registered = 1;
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}
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return 0;
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}
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console_initcall(early_uart_console_init);
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int __init early_serial_console_init(char *cmdline)
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int __init setup_early_serial8250_console(char *cmdline)
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{
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char *options;
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int err;
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options = strstr(cmdline, "console=uart,");
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if (!options)
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return -ENODEV;
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options = strstr(cmdline, "uart8250,");
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if (!options) {
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options = strstr(cmdline, "uart,");
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if (!options)
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return 0;
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}
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options = strchr(cmdline, ',') + 1;
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if ((err = early_uart_setup(NULL, options)) < 0)
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if ((err = early_serial8250_setup(options)) < 0)
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return err;
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return early_uart_console_init();
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}
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static int __init early_uart_console_switch(void)
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{
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struct early_uart_device *device = &early_device;
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struct uart_port *port = &device->port;
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int mmio, line;
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if (!(early_uart_console.flags & CON_ENABLED))
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return 0;
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/* Try to start the normal driver on a matching line. */
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mmio = (port->iotype == UPIO_MEM);
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line = serial8250_start_console(port, device->options);
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if (line < 0)
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printk("No ttyS device at %s 0x%lx for console\n",
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mmio ? "MMIO" : "I/O port",
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mmio ? port->mapbase :
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(unsigned long) port->iobase);
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unregister_console(&early_uart_console);
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if (mmio)
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iounmap(port->membase);
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register_console(&early_serial8250_console);
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return 0;
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}
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late_initcall(early_uart_console_switch);
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int __init serial8250_find_port_for_earlycon(void)
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{
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struct early_serial8250_device *device = &early_device;
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struct uart_port *port = &device->port;
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int line;
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int ret;
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if (!device->port.membase && !device->port.iobase)
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return -ENODEV;
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line = serial8250_find_port(port);
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if (line < 0)
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return -ENODEV;
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ret = update_console_cmdline("uart", 8250,
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"ttyS", line, device->options);
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if (ret < 0)
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ret = update_console_cmdline("uart", 0,
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"ttyS", line, device->options);
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return ret;
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}
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early_param("earlycon", setup_early_serial8250_console);
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@ -62,8 +62,22 @@ config SERIAL_8250_CONSOLE
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kernel will automatically use the first serial line, /dev/ttyS0, as
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system console.
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you can set that using a kernel command line option such as
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"console=uart8250,io,0x3f8,9600n8"
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"console=uart8250,mmio,0xff5e0000,115200n8".
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and it will switch to normal serial console when correponding port is
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ready.
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"earlycon=uart8250,io,0x3f8,9600n8"
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"earlycon=uart8250,mmio,0xff5e0000,115200n8".
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it will not only setup early console.
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If unsure, say N.
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config FIX_EARLYCON_MEM
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bool
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depends on X86
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default y
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config SERIAL_8250_GSC
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tristate
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depends on SERIAL_8250 && GSC
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