From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- drivers/tty/serial/earlycon.c | 217 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 217 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 000000000..6dc471e30 --- /dev/null +++ b/drivers/tty/serial/earlycon.c @@ -0,0 +1,217 @@ +/* + * 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. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include + +#ifdef CONFIG_FIX_EARLYCON_MEM +#include +#endif + +#include + +static struct console early_con = { + .name = "uart", /* 8250 console switch requires this name */ + .flags = CON_PRINTBUFFER | CON_BOOT, + .index = -1, +}; + +static struct earlycon_device early_console_dev = { + .con = &early_con, +}; + +extern struct earlycon_id __earlycon_table[]; +static const struct earlycon_id __earlycon_table_sentinel + __used __section(__earlycon_table_end); + +static const struct of_device_id __earlycon_of_table_sentinel + __used __section(__earlycon_of_table_end); + +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 length; + unsigned long addr; + + if (uart_parse_earlycon(options, &port->iotype, &addr, &options)) + return -EINVAL; + + switch (port->iotype) { + case UPIO_MEM32: + port->regshift = 2; /* fall-through */ + case UPIO_MEM: + port->mapbase = addr; + break; + case UPIO_PORT: + port->iobase = addr; + break; + default: + return -EINVAL; + } + + if (options) { + device->baud = simple_strtoul(options, NULL, 0); + length = min(strcspn(options, " ") + 1, + (size_t)(sizeof(device->options))); + strlcpy(device->options, options, length); + } + + if (port->iotype == UPIO_MEM || port->iotype == UPIO_MEM32) + pr_info("Early serial console at MMIO%s 0x%llx (options '%s')\n", + (port->iotype == UPIO_MEM32) ? "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; +} + +static int __init register_earlycon(char *buf, const struct earlycon_id *match) +{ + int err; + struct uart_port *port = &early_console_dev.port; + + /* On parsing error, pass the options buf to the setup function */ + if (buf && !parse_options(&early_console_dev, buf)) + buf = NULL; + + port->uartclk = BASE_BAUD * 16; + if (port->mapbase) + port->membase = earlycon_map(port->mapbase, 64); + + early_console_dev.con->data = &early_console_dev; + err = match->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; +} + +/** + * setup_earlycon - match and register earlycon console + * @buf: earlycon param string + * + * Registers the earlycon console matching the earlycon specified + * in the param string @buf. Acceptable param strings are of the form + * ,io|mmio|mmio32,, + * ,0x, + * , + * + * + * Only for the third form does the earlycon setup() method receive the + * string in the 'options' parameter; all other forms set + * the parameter to NULL. + * + * Returns 0 if an attempt to register the earlycon was made, + * otherwise negative error code + */ +int __init setup_earlycon(char *buf) +{ + const struct earlycon_id *match; + + if (!buf || !buf[0]) + return -EINVAL; + + if (early_con.flags & CON_ENABLED) + return -EALREADY; + + for (match = __earlycon_table; match->name[0]; match++) { + size_t len = strlen(match->name); + + if (strncmp(buf, match->name, len)) + continue; + + if (buf[len]) { + if (buf[len] != ',') + continue; + buf += len + 1; + } else + buf = NULL; + + return register_earlycon(buf, match); + } + + return -ENOENT; +} + +/* early_param wrapper for setup_earlycon() */ +static int __init param_setup_earlycon(char *buf) +{ + int err; + + /* + * Just 'earlycon' is a valid param for devicetree earlycons; + * don't generate a warning from parse_early_params() in that case + */ + if (!buf || !buf[0]) + return 0; + + err = setup_earlycon(buf); + if (err == -ENOENT || err == -EALREADY) + return 0; + return err; +} +early_param("earlycon", param_setup_earlycon); + +int __init of_setup_earlycon(unsigned long addr, + int (*setup)(struct earlycon_device *, const char *)) +{ + int err; + struct uart_port *port = &early_console_dev.port; + + port->iotype = UPIO_MEM; + port->mapbase = addr; + port->uartclk = BASE_BAUD * 16; + port->membase = earlycon_map(addr, SZ_4K); + + early_console_dev.con->data = &early_console_dev; + err = setup(&early_console_dev, NULL); + if (err < 0) + return err; + if (!early_console_dev.con->write) + return -ENODEV; + + + register_console(early_console_dev.con); + return 0; +} -- cgit v1.2.3-54-g00ecf