diff options
| -rw-r--r-- | drivers/tty/serial/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/tty/serial/Makefile | 2 | ||||
| -rw-r--r-- | drivers/tty/serial/earlycon.c | 152 | ||||
| -rw-r--r-- | include/linux/serial_core.h | 16 |
4 files changed, 177 insertions, 0 deletions
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index 30530e47cdf0..9fb6028ad900 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -7,6 +7,13 @@ if TTY menu "Serial drivers" depends on HAS_IOMEM +config SERIAL_EARLYCON + bool + help + Support for early consoles with the earlycon parameter. This enables + the console before standard serial driver is probed. The console is + enabled when early_param is processed. + source "drivers/tty/serial/8250/Kconfig" comment "Non-8250 serial port support" diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile index 5f2a3f493ab9..28048178f308 100644 --- a/drivers/tty/serial/Makefile +++ b/drivers/tty/serial/Makefile @@ -5,6 +5,8 @@ obj-$(CONFIG_SERIAL_CORE) += serial_core.o obj-$(CONFIG_SERIAL_21285) += 21285.o +obj-$(CONFIG_SERIAL_EARLYCON) += earlycon.o + # These Sparc drivers have to appear before others such as 8250 # which share ttySx minor node space. Otherwise console device # names change and other unplesantries. diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c new file mode 100644 index 000000000000..73bf1e21aae0 --- /dev/null +++ b/drivers/tty/serial/earlycon.c @@ -0,0 +1,152 @@ +/* + * Copyright (C) 2014 Linaro Ltd. + * Author: Rob Herring <robh@kernel.org> + * + * Based on 8250 earlycon: + * (c) Copyright 2004 Hewlett-Packard Development Company, L.P. + * Bjorn Helgaas <bjorn.helgaas@hp.com> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include <linux/console.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/serial_core.h> + +#ifdef CONFIG_FIX_EARLYCON_MEM +#include <asm/fixmap.h> +#endif + +#include <asm/serial.h> + +static struct console early_con = { + .name = "earlycon", + .flags = CON_PRINTBUFFER | CON_BOOT, + .index = -1, +}; + +static struct earlycon_device early_console_dev = { + .con = &early_con, +}; + +static void __iomem * __init earlycon_map(unsigned long paddr, size_t size) +{ + void __iomem *base; +#ifdef CONFIG_FIX_EARLYCON_MEM + set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr & PAGE_MASK); + base = (void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE); + base += paddr & ~PAGE_MASK; +#else + base = ioremap(paddr, size); +#endif + if (!base) + pr_err("%s: Couldn't map 0x%llx\n", __func__, + (unsigned long long)paddr); + + return base; +} + +static int __init parse_options(struct earlycon_device *device, + char *options) +{ + struct uart_port *port = &device->port; + int mmio, mmio32, length, ret; + unsigned long addr; + + if (!options) + return -ENODEV; + + mmio = !strncmp(options, "mmio,", 5); + mmio32 = !strncmp(options, "mmio32,", 7); + if (mmio || mmio32) { + port->iotype = (mmio ? UPIO_MEM : UPIO_MEM32); + options += mmio ? 5 : 7; + ret = kstrtoul(options, 0, &addr); + if (ret) + return ret; + port->mapbase = addr; + if (mmio32) + port->regshift = 2; + } else if (!strncmp(options, "io,", 3)) { + port->iotype = UPIO_PORT; + options += 3; + ret = kstrtoul(options, 0, &addr); + if (ret) + return ret; + port->iobase = addr; + mmio = 0; + } else if (!strncmp(options, "0x", 2)) { + port->iotype = UPIO_MEM; + ret = kstrtoul(options, 0, &addr); + if (ret) + return ret; + port->mapbase = addr; + } else { + return -EINVAL; + } + + port->uartclk = BASE_BAUD * 16; + + options = strchr(options, ','); + if (options) { + options++; + ret = kstrtouint(options, 0, &device->baud); + if (ret) + return ret; + length = min(strcspn(options, " ") + 1, + (size_t)(sizeof(device->options))); + strlcpy(device->options, options, length); + } + + if (mmio || mmio32) + pr_info("Early serial console at MMIO%s 0x%llx (options '%s')\n", + mmio32 ? "32" : "", + (unsigned long long)port->mapbase, + device->options); + else + pr_info("Early serial console at I/O port 0x%lx (options '%s')\n", + port->iobase, + device->options); + + return 0; +} + +int __init setup_earlycon(char *buf, const char *match, + int (*setup)(struct earlycon_device *, const char *)) +{ + int err; + size_t len; + struct uart_port *port = &early_console_dev.port; + + if (!buf || !match || !setup) + return 0; + + len = strlen(match); + if (strncmp(buf, match, len)) + return 0; + if (buf[len] && (buf[len] != ',')) + return 0; + + buf += len + 1; + + err = parse_options(&early_console_dev, buf); + /* On parsing error, pass the options buf to the setup function */ + if (!err) + buf = NULL; + + if (port->mapbase) + port->membase = earlycon_map(port->mapbase, 64); + + early_console_dev.con->data = &early_console_dev; + err = setup(&early_console_dev, buf); + if (err < 0) + return err; + if (!early_console_dev.con->write) + return -ENODEV; + + register_console(early_console_dev.con); + return 0; +} diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index f729be981da0..7a15b5b24c0b 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -285,6 +285,22 @@ static inline int uart_poll_timeout(struct uart_port *port) /* * Console helpers. */ +struct earlycon_device { + struct console *con; + struct uart_port port; + char options[16]; /* e.g., 115200n8 */ + unsigned int baud; +}; +int setup_earlycon(char *buf, const char *match, + int (*setup)(struct earlycon_device *, const char *)); + +#define EARLYCON_DECLARE(name, func) \ +static int __init name ## _setup_earlycon(char *buf) \ +{ \ + return setup_earlycon(buf, __stringify(name), func); \ +} \ +early_param("earlycon", name ## _setup_earlycon); + struct uart_port *uart_get_console(struct uart_port *ports, int nr, struct console *c); void uart_parse_options(char *options, int *baud, int *parity, int *bits, |