From 9aac5887595b765b6f64b2af08b785e82e095b57 Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Fri, 18 Apr 2014 17:19:55 -0500 Subject: tty/serial: add generic serial earlycon This introduces generic earlycon infrastructure for serial devices based on the 8250 earlycon. This allows for supporting earlycon option with other serial devices. The earlycon output is enabled at the time early_params are processed. Only architectures that have fixmap support or have functional ioremap when early_params are processed are supported. This is the same restriction that the 8250 driver had. Signed-off-by: Rob Herring Cc: Jiri Slaby Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/earlycon.c | 152 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 152 insertions(+) create mode 100644 drivers/tty/serial/earlycon.c (limited to 'drivers/tty/serial/earlycon.c') 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 + * + * Based on 8250 earlycon: + * (c) Copyright 2004 Hewlett-Packard Development Company, L.P. + * Bjorn Helgaas + * + * 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 +#include +#include +#include +#include + +#ifdef CONFIG_FIX_EARLYCON_MEM +#include +#endif + +#include + +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; +} -- cgit