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tty/serial: convert 8250 to generic earlycon
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With the generic earlycon infrastructure in place, convert the 8250
early console to use it.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Rob Herring authored and Greg Kroah-Hartman committed Apr 24, 2014
1 parent 9aac588 commit d2fd681
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Showing 2 changed files with 16 additions and 123 deletions.
138 changes: 15 additions & 123 deletions drivers/tty/serial/8250/8250_early.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -35,18 +35,8 @@
#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_serial8250_device {
struct uart_port port;
char options[16]; /* e.g., 115200n8 */
unsigned int baud;
};

static struct early_serial8250_device early_device;
static struct earlycon_device *early_device;

unsigned int __weak __init serial8250_early_in(struct uart_port *port, int offset)
{
Expand Down Expand Up @@ -100,7 +90,7 @@ static void __init serial_putc(struct uart_port *port, int c)
static void __init early_serial8250_write(struct console *console,
const char *s, unsigned int count)
{
struct uart_port *port = &early_device.port;
struct uart_port *port = &early_device->port;
unsigned int ier;

/* Save the IER and disable interrupts */
Expand Down Expand Up @@ -129,7 +119,7 @@ static unsigned int __init probe_baud(struct uart_port *port)
return (port->uartclk / 16) / quot;
}

static void __init init_port(struct early_serial8250_device *device)
static void __init init_port(struct earlycon_device *device)
{
struct uart_port *port = &device->port;
unsigned int divisor;
Expand All @@ -148,128 +138,32 @@ static void __init init_port(struct early_serial8250_device *device)
serial8250_early_out(port, UART_LCR, c & ~UART_LCR_DLAB);
}

static int __init parse_options(struct early_serial8250_device *device,
char *options)
{
struct uart_port *port = &device->port;
int mmio, mmio32, length;

if (!options)
return -ENODEV;

port->uartclk = BASE_BAUD * 16;

mmio = !strncmp(options, "mmio,", 5);
mmio32 = !strncmp(options, "mmio32,", 7);
if (mmio || mmio32) {
port->iotype = (mmio ? UPIO_MEM : UPIO_MEM32);
port->mapbase = simple_strtoul(options + (mmio ? 5 : 7),
&options, 0);
if (mmio32)
port->regshift = 2;
#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_nocache(port->mapbase, 64);
if (!port->membase) {
printk(KERN_ERR "%s: Couldn't ioremap 0x%llx\n",
__func__,
(unsigned long long) port->mapbase);
return -ENOMEM;
}
#endif
} else if (!strncmp(options, "io,", 3)) {
port->iotype = UPIO_PORT;
port->iobase = simple_strtoul(options + 3, &options, 0);
mmio = 0;
} else
return -EINVAL;

options = strchr(options, ',');
if (options) {
options++;
device->baud = simple_strtoul(options, NULL, 0);
length = min(strcspn(options, " ") + 1,
(size_t)(sizeof(device->options)));
strlcpy(device->options, options, length);
} else {
device->baud = probe_baud(port);
snprintf(device->options, sizeof(device->options), "%u",
device->baud);
}

if (mmio || mmio32)
printk(KERN_INFO
"Early serial console at MMIO%s 0x%llx (options '%s')\n",
mmio32 ? "32" : "",
(unsigned long long)port->mapbase,
device->options);
else
printk(KERN_INFO
"Early serial console at I/O port 0x%lx (options '%s')\n",
port->iobase,
device->options);

return 0;
}

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)
static int __init early_serial8250_setup(struct earlycon_device *device,
const char *options)
{
struct early_serial8250_device *device = &early_device;
int err;

if (device->port.membase || device->port.iobase)
if (!(device->port.membase || device->port.iobase))
return 0;

err = parse_options(device, options);
if (err < 0)
return err;
if (!device->baud)
device->baud = probe_baud(&device->port);

init_port(device);
return 0;
}

int __init setup_early_serial8250_console(char *cmdline)
{
char *options;
int err;

options = strstr(cmdline, "uart8250,");
if (!options) {
options = strstr(cmdline, "uart,");
if (!options)
return 0;
}

options = strchr(cmdline, ',') + 1;
err = early_serial8250_setup(options);
if (err < 0)
return err;

register_console(&early_serial8250_console);

early_device = device;
device->con->write = early_serial8250_write;
return 0;
}
EARLYCON_DECLARE(uart8250, early_serial8250_setup);
EARLYCON_DECLARE(uart, early_serial8250_setup);

int serial8250_find_port_for_earlycon(void)
{
struct early_serial8250_device *device = &early_device;
struct uart_port *port = &device->port;
struct earlycon_device *device = early_device;
struct uart_port *port = device ? &device->port : NULL;
int line;
int ret;

if (!device->port.membase && !device->port.iobase)
if (!port || (!port->membase && !port->iobase))
return -ENODEV;

line = serial8250_find_port(port);
Expand All @@ -284,5 +178,3 @@ int serial8250_find_port_for_earlycon(void)

return ret;
}

early_param("earlycon", setup_early_serial8250_console);
1 change: 1 addition & 0 deletions drivers/tty/serial/8250/Kconfig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -61,6 +61,7 @@ config SERIAL_8250_CONSOLE
bool "Console on 8250/16550 and compatible serial port"
depends on SERIAL_8250=y
select SERIAL_CORE_CONSOLE
select SERIAL_EARLYCON
---help---
If you say Y here, it will be possible to use a serial port as the
system console (the system console is the device which receives all
Expand Down

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