linux/drivers/tty/serial/earlycon.c

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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/of.h>
#include <linux/of_fdt.h>
#ifdef CONFIG_FIX_EARLYCON_MEM
#include <asm/fixmap.h>
#endif
#include <asm/serial.h>
static struct console early_con = {
.name = "uart", /* fixed up at earlycon registration */
.flags = CON_PRINTBUFFER | CON_BOOT,
.index = 0,
};
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 void __init earlycon_init(struct earlycon_device *device,
const char *name)
{
struct console *earlycon = device->con;
struct uart_port *port = &device->port;
const char *s;
size_t len;
/* scan backwards from end of string for first non-numeral */
for (s = name + strlen(name);
s > name && s[-1] >= '0' && s[-1] <= '9';
s--)
;
if (*s)
earlycon->index = simple_strtoul(s, NULL, 10);
len = s - name;
strlcpy(earlycon->name, name, min(len + 1, sizeof(earlycon->name)));
earlycon->data = &early_console_dev;
if (port->iotype == UPIO_MEM || port->iotype == UPIO_MEM16 ||
port->iotype == UPIO_MEM32 || port->iotype == UPIO_MEM32BE)
pr_info("%s%d at MMIO%s %pa (options '%s')\n",
earlycon->name, earlycon->index,
(port->iotype == UPIO_MEM) ? "" :
(port->iotype == UPIO_MEM16) ? "16" :
(port->iotype == UPIO_MEM32) ? "32" : "32be",
&port->mapbase, device->options);
else
pr_info("%s%d at I/O port 0x%lx (options '%s')\n",
earlycon->name, earlycon->index,
port->iobase, device->options);
}
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_MEM:
port->mapbase = addr;
break;
case UPIO_MEM16:
port->regshift = 1;
port->mapbase = addr;
break;
case UPIO_MEM32:
case UPIO_MEM32BE:
port->regshift = 2;
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);
}
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;
serial: earlycon: Add missing spinlock initialization If an earlycon console driver needs to acquire the uart_port.lock spinlock for serial console output, and CONFIG_DEBUG_SPINLOCK=y: BUG: spinlock bad magic on CPU#0, swapper/0 lock: sci_ports+0x0/0x3480, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0 CPU: 0 PID: 0 Comm: swapper Not tainted 4.4.0-rc2-koelsch-g62ea5edf143bb1d0-dirty #2083 Hardware name: Generic R8A7791 (Flattened Device Tree) [<c00173a0>] (unwind_backtrace) from [<c0013094>] (show_stack+0x10/0x14) [<c0013094>] (show_stack) from [<c01f2338>] (dump_stack+0x70/0x8c) [<c01f2338>] (dump_stack) from [<c00702d8>] (do_raw_spin_lock+0x20/0x190) [<c00702d8>] (do_raw_spin_lock) from [<c0267590>] (serial_console_write+0x4c/0x130) [<c0267590>] (serial_console_write) from [<c00734c4>] (call_console_drivers.constprop.13+0xc8/0xec) [<c00734c4>] (call_console_drivers.constprop.13) from [<c0074ef0>] (console_unlock+0x354/0x440) [<c0074ef0>] (console_unlock) from [<c0075bb4>] (register_console+0x2a0/0x394) [<c0075bb4>] (register_console) from [<c06cb750>] (of_setup_earlycon+0x90/0xa4) [<c06cb750>] (of_setup_earlycon) from [<c06cfb60>] (setup_of_earlycon+0x118/0x13c) [<c06cfb60>] (setup_of_earlycon) from [<c06b34ac>] (do_early_param+0x64/0xb4) [<c06b34ac>] (do_early_param) from [<c00472c0>] (parse_args+0x254/0x350) [<c00472c0>] (parse_args) from [<c06b3860>] (parse_early_options+0x2c/0x3c) [<c06b3860>] (parse_early_options) from [<c06b389c>] (parse_early_param+0x2c/0x40) [<c06b389c>] (parse_early_param) from [<c06b5b08>] (setup_arch+0x520/0xaf0) [<c06b5b08>] (setup_arch) from [<c06b3948>] (start_kernel+0x94/0x370) [<c06b3948>] (start_kernel) from [<40008090>] (0x40008090) Initialize the spinlock in of_setup_earlycon() and register_earlycon(), to fix this for both DT-based and legacy earlycon. If the driver would reinitialize the spinlock again, this is harmless, as it's allowed to reinitialize an unlocked spinlock. Alternatives are: - Drivers having an early_serial_console_write() that only performs the core functionality of serial_console_write(), without acquiring the lock (which may be unsafe, depending on the hardware), - Drivers initializing the spinlock in their private earlycon setup functions. As uart_port is owned by generic serial_core, and uart_port.lock is initialized by uart_add_one_port() for the normal case, this can better be handled in the earlycon core. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Reported-by: Bjorn Andersson <bjorn.andersson@sonymobile.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-11-27 10:13:48 +00:00
spin_lock_init(&port->lock);
port->uartclk = BASE_BAUD * 16;
if (port->mapbase)
port->membase = earlycon_map(port->mapbase, 64);
earlycon_init(&early_console_dev, match->name);
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|mmio32be,<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 < __earlycon_table_end; 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);
#ifdef CONFIG_OF_EARLY_FLATTREE
int __init of_setup_earlycon(const struct earlycon_id *match,
unsigned long node,
const char *options)
{
int err;
struct uart_port *port = &early_console_dev.port;
const __be32 *val;
bool big_endian;
u64 addr;
serial: earlycon: Add missing spinlock initialization If an earlycon console driver needs to acquire the uart_port.lock spinlock for serial console output, and CONFIG_DEBUG_SPINLOCK=y: BUG: spinlock bad magic on CPU#0, swapper/0 lock: sci_ports+0x0/0x3480, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0 CPU: 0 PID: 0 Comm: swapper Not tainted 4.4.0-rc2-koelsch-g62ea5edf143bb1d0-dirty #2083 Hardware name: Generic R8A7791 (Flattened Device Tree) [<c00173a0>] (unwind_backtrace) from [<c0013094>] (show_stack+0x10/0x14) [<c0013094>] (show_stack) from [<c01f2338>] (dump_stack+0x70/0x8c) [<c01f2338>] (dump_stack) from [<c00702d8>] (do_raw_spin_lock+0x20/0x190) [<c00702d8>] (do_raw_spin_lock) from [<c0267590>] (serial_console_write+0x4c/0x130) [<c0267590>] (serial_console_write) from [<c00734c4>] (call_console_drivers.constprop.13+0xc8/0xec) [<c00734c4>] (call_console_drivers.constprop.13) from [<c0074ef0>] (console_unlock+0x354/0x440) [<c0074ef0>] (console_unlock) from [<c0075bb4>] (register_console+0x2a0/0x394) [<c0075bb4>] (register_console) from [<c06cb750>] (of_setup_earlycon+0x90/0xa4) [<c06cb750>] (of_setup_earlycon) from [<c06cfb60>] (setup_of_earlycon+0x118/0x13c) [<c06cfb60>] (setup_of_earlycon) from [<c06b34ac>] (do_early_param+0x64/0xb4) [<c06b34ac>] (do_early_param) from [<c00472c0>] (parse_args+0x254/0x350) [<c00472c0>] (parse_args) from [<c06b3860>] (parse_early_options+0x2c/0x3c) [<c06b3860>] (parse_early_options) from [<c06b389c>] (parse_early_param+0x2c/0x40) [<c06b389c>] (parse_early_param) from [<c06b5b08>] (setup_arch+0x520/0xaf0) [<c06b5b08>] (setup_arch) from [<c06b3948>] (start_kernel+0x94/0x370) [<c06b3948>] (start_kernel) from [<40008090>] (0x40008090) Initialize the spinlock in of_setup_earlycon() and register_earlycon(), to fix this for both DT-based and legacy earlycon. If the driver would reinitialize the spinlock again, this is harmless, as it's allowed to reinitialize an unlocked spinlock. Alternatives are: - Drivers having an early_serial_console_write() that only performs the core functionality of serial_console_write(), without acquiring the lock (which may be unsafe, depending on the hardware), - Drivers initializing the spinlock in their private earlycon setup functions. As uart_port is owned by generic serial_core, and uart_port.lock is initialized by uart_add_one_port() for the normal case, this can better be handled in the earlycon core. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Reported-by: Bjorn Andersson <bjorn.andersson@sonymobile.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-11-27 10:13:48 +00:00
spin_lock_init(&port->lock);
port->iotype = UPIO_MEM;
addr = of_flat_dt_translate_address(node);
if (addr == OF_BAD_ADDR) {
pr_warn("[%s] bad address\n", match->name);
return -ENXIO;
}
port->mapbase = addr;
port->uartclk = BASE_BAUD * 16;
port->membase = earlycon_map(port->mapbase, SZ_4K);
val = of_get_flat_dt_prop(node, "reg-offset", NULL);
if (val)
port->mapbase += be32_to_cpu(*val);
val = of_get_flat_dt_prop(node, "reg-shift", NULL);
if (val)
port->regshift = be32_to_cpu(*val);
big_endian = of_get_flat_dt_prop(node, "big-endian", NULL) != NULL ||
(IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
of_get_flat_dt_prop(node, "native-endian", NULL) != NULL);
val = of_get_flat_dt_prop(node, "reg-io-width", NULL);
if (val) {
switch (be32_to_cpu(*val)) {
case 1:
port->iotype = UPIO_MEM;
break;
case 2:
port->iotype = UPIO_MEM16;
break;
case 4:
port->iotype = (big_endian) ? UPIO_MEM32BE : UPIO_MEM32;
break;
default:
pr_warn("[%s] unsupported reg-io-width\n", match->name);
return -EINVAL;
}
}
if (options) {
strlcpy(early_console_dev.options, options,
sizeof(early_console_dev.options));
}
earlycon_init(&early_console_dev, match->name);
err = match->setup(&early_console_dev, options);
if (err < 0)
return err;
if (!early_console_dev.con->write)
return -ENODEV;
register_console(early_console_dev.con);
return 0;
}
#endif /* CONFIG_OF_EARLY_FLATTREE */