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/*
* 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/console.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/serial_core.h>
#include <linux/sizes.h>
#include <linux/mod_devicetable.h>
#ifdef CONFIG_FIX_EARLYCON_MEM
#include <asm/fixmap.h>
#endif
#include <asm/serial.h>
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
* <name>,io|mmio|mmio32,<addr>,<options>
* <name>,0x<addr>,<options>
* <name>,<options>
* <name>
*
* Only for the third form does the earlycon setup() method receive the
* <options> 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) {
pr_warn("no match for %s\n", buf);
err = 0;
} else if (err == -EALREADY) {
pr_warn("already registered\n");
err = 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;
}
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