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>
diff --git a/drivers/firmware/pcdp.c b/drivers/firmware/pcdp.c
index 2b4b76e..58e9f8e 100644
--- a/drivers/firmware/pcdp.c
+++ b/drivers/firmware/pcdp.c
@@ -15,6 +15,7 @@
#include <linux/console.h>
#include <linux/efi.h>
#include <linux/serial.h>
+#include <linux/serial_8250.h>
#include <asm/vga.h>
#include "pcdp.h"
@@ -27,7 +28,7 @@
char parity;
mmio = (uart->addr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY);
- p += sprintf(p, "console=uart,%s,0x%lx",
+ p += sprintf(p, "uart8250,%s,0x%lx",
mmio ? "mmio" : "io", uart->addr.address);
if (uart->baud) {
p += sprintf(p, ",%lu", uart->baud);
@@ -41,7 +42,8 @@
}
}
- return early_serial_console_init(options);
+ add_preferred_console("uart", 8250, &options[9]);
+ return setup_early_serial8250_console(options);
#else
return -ENODEV;
#endif
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index c84dab0..0b3ec38 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -2514,12 +2514,18 @@
return uart_set_options(port, co, baud, parity, bits, flow);
}
+static int __init serial8250_console_early_setup(void)
+{
+ return serial8250_find_port_for_earlycon();
+}
+
static struct uart_driver serial8250_reg;
static struct console serial8250_console = {
.name = "ttyS",
.write = serial8250_console_write,
.device = uart_console_device,
.setup = serial8250_console_setup,
+ .early_setup = serial8250_console_early_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &serial8250_reg,
@@ -2533,7 +2539,7 @@
}
console_initcall(serial8250_console_init);
-static int __init find_port(struct uart_port *p)
+int serial8250_find_port(struct uart_port *p)
{
int line;
struct uart_port *port;
@@ -2546,26 +2552,6 @@
return -ENODEV;
}
-int __init serial8250_start_console(struct uart_port *port, char *options)
-{
- int line;
-
- line = find_port(port);
- if (line < 0)
- return -ENODEV;
-
- add_preferred_console("ttyS", line, options);
- printk("Adding console on ttyS%d at %s 0x%lx (options '%s')\n",
- line, port->iotype == UPIO_MEM ? "MMIO" : "I/O port",
- port->iotype == UPIO_MEM ? (unsigned long) port->mapbase :
- (unsigned long) port->iobase, options);
- if (!(serial8250_console.flags & CON_ENABLED)) {
- serial8250_console.flags &= ~CON_PRINTBUFFER;
- register_console(&serial8250_console);
- }
- return line;
-}
-
#define SERIAL8250_CONSOLE &serial8250_console
#else
#define SERIAL8250_CONSOLE NULL
diff --git a/drivers/serial/8250_early.c b/drivers/serial/8250_early.c
index 7e51119..947c205 100644
--- a/drivers/serial/8250_early.c
+++ b/drivers/serial/8250_early.c
@@ -17,13 +17,11 @@
* we locate the device directly by its MMIO or I/O port address.
*
* The user can specify the device directly, e.g.,
- * console=uart,io,0x3f8,9600n8
- * console=uart,mmio,0xff5e0000,115200n8
- * or platform code can call early_uart_console_init() to set
- * the early UART device.
- *
- * After the normal serial driver starts, we try to locate the
- * matching ttyS device and start a console there.
+ * earlycon=uart8250,io,0x3f8,9600n8
+ * earlycon=uart8250,mmio,0xff5e0000,115200n8
+ * or
+ * console=uart8250,io,0x3f8,9600n8
+ * console=uart8250,mmio,0xff5e0000,115200n8
*/
#include <linux/tty.h>
@@ -32,17 +30,21 @@
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
#include <linux/serial.h>
+#include <linux/serial_8250.h>
#include <asm/io.h>
#include <asm/serial.h>
+#ifdef CONFIG_FIX_EARLYCON_MEM
+#include <asm/pgtable.h>
+#include <asm/fixmap.h>
+#endif
-struct early_uart_device {
+struct early_serial8250_device {
struct uart_port port;
char options[16]; /* e.g., 115200n8 */
unsigned int baud;
};
-static struct early_uart_device early_device __initdata;
-static int early_uart_registered __initdata;
+static struct early_serial8250_device early_device;
static unsigned int __init serial_in(struct uart_port *port, int offset)
{
@@ -80,7 +82,7 @@
serial_out(port, UART_TX, c);
}
-static void __init early_uart_write(struct console *console, const char *s, unsigned int count)
+static void __init early_serial8250_write(struct console *console, const char *s, unsigned int count)
{
struct uart_port *port = &early_device.port;
unsigned int ier;
@@ -111,7 +113,7 @@
return (port->uartclk / 16) / quot;
}
-static void __init init_port(struct early_uart_device *device)
+static void __init init_port(struct early_serial8250_device *device)
{
struct uart_port *port = &device->port;
unsigned int divisor;
@@ -130,10 +132,9 @@
serial_out(port, UART_LCR, c & ~UART_LCR_DLAB);
}
-static int __init parse_options(struct early_uart_device *device, char *options)
+static int __init parse_options(struct early_serial8250_device *device, char *options)
{
struct uart_port *port = &device->port;
- int mapsize = 64;
int mmio, length;
if (!options)
@@ -143,12 +144,18 @@
if (!strncmp(options, "mmio,", 5)) {
port->iotype = UPIO_MEM;
port->mapbase = simple_strtoul(options + 5, &options, 0);
- port->membase = ioremap(port->mapbase, mapsize);
+#ifdef CONFIG_FIX_EARLYCON_MEM
+ set_fixmap_nocache(FIX_EARLYCON_MEM_BASE, port->mapbase & PAGE_MASK);
+ port->membase = (void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE);
+ port->membase += port->mapbase & ~PAGE_MASK;
+#else
+ port->membase = ioremap(port->mapbase, 64);
if (!port->membase) {
printk(KERN_ERR "%s: Couldn't ioremap 0x%lx\n",
__FUNCTION__, port->mapbase);
return -ENOMEM;
}
+#endif
mmio = 1;
} else if (!strncmp(options, "io,", 3)) {
port->iotype = UPIO_PORT;
@@ -175,9 +182,16 @@
return 0;
}
-static int __init early_uart_setup(struct console *console, char *options)
+static struct console early_serial8250_console __initdata = {
+ .name = "uart",
+ .write = early_serial8250_write,
+ .flags = CON_PRINTBUFFER | CON_BOOT,
+ .index = -1,
+};
+
+static int __init early_serial8250_setup(char *options)
{
- struct early_uart_device *device = &early_device;
+ struct early_serial8250_device *device = &early_device;
int err;
if (device->port.membase || device->port.iobase)
@@ -190,61 +204,48 @@
return 0;
}
-static struct console early_uart_console __initdata = {
- .name = "uart",
- .write = early_uart_write,
- .setup = early_uart_setup,
- .flags = CON_PRINTBUFFER,
- .index = -1,
-};
-
-static int __init early_uart_console_init(void)
-{
- if (!early_uart_registered) {
- register_console(&early_uart_console);
- early_uart_registered = 1;
- }
- return 0;
-}
-console_initcall(early_uart_console_init);
-
-int __init early_serial_console_init(char *cmdline)
+int __init setup_early_serial8250_console(char *cmdline)
{
char *options;
int err;
- options = strstr(cmdline, "console=uart,");
- if (!options)
- return -ENODEV;
+ options = strstr(cmdline, "uart8250,");
+ if (!options) {
+ options = strstr(cmdline, "uart,");
+ if (!options)
+ return 0;
+ }
options = strchr(cmdline, ',') + 1;
- if ((err = early_uart_setup(NULL, options)) < 0)
+ if ((err = early_serial8250_setup(options)) < 0)
return err;
- return early_uart_console_init();
-}
-static int __init early_uart_console_switch(void)
-{
- struct early_uart_device *device = &early_device;
- struct uart_port *port = &device->port;
- int mmio, line;
-
- if (!(early_uart_console.flags & CON_ENABLED))
- return 0;
-
- /* Try to start the normal driver on a matching line. */
- mmio = (port->iotype == UPIO_MEM);
- line = serial8250_start_console(port, device->options);
- if (line < 0)
- printk("No ttyS device at %s 0x%lx for console\n",
- mmio ? "MMIO" : "I/O port",
- mmio ? port->mapbase :
- (unsigned long) port->iobase);
-
- unregister_console(&early_uart_console);
- if (mmio)
- iounmap(port->membase);
+ register_console(&early_serial8250_console);
return 0;
}
-late_initcall(early_uart_console_switch);
+
+int __init serial8250_find_port_for_earlycon(void)
+{
+ struct early_serial8250_device *device = &early_device;
+ struct uart_port *port = &device->port;
+ int line;
+ int ret;
+
+ if (!device->port.membase && !device->port.iobase)
+ return -ENODEV;
+
+ line = serial8250_find_port(port);
+ if (line < 0)
+ return -ENODEV;
+
+ ret = update_console_cmdline("uart", 8250,
+ "ttyS", line, device->options);
+ if (ret < 0)
+ ret = update_console_cmdline("uart", 0,
+ "ttyS", line, device->options);
+
+ return ret;
+}
+
+early_param("earlycon", setup_early_serial8250_console);
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 2adbed4..cab42cb 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -62,8 +62,22 @@
kernel will automatically use the first serial line, /dev/ttyS0, as
system console.
+ you can set that using a kernel command line option such as
+ "console=uart8250,io,0x3f8,9600n8"
+ "console=uart8250,mmio,0xff5e0000,115200n8".
+ and it will switch to normal serial console when correponding port is
+ ready.
+ "earlycon=uart8250,io,0x3f8,9600n8"
+ "earlycon=uart8250,mmio,0xff5e0000,115200n8".
+ it will not only setup early console.
+
If unsure, say N.
+config FIX_EARLYCON_MEM
+ bool
+ depends on X86
+ default y
+
config SERIAL_8250_GSC
tristate
depends on SERIAL_8250 && GSC