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// SPDX-License-Identifier: GPL-2.0
/*
* Kernel command line console options for hardware based addressing
*
* Copyright (C) 2023 Texas Instruments Incorporated - https://www.ti.com/
* Author: Tony Lindgren <tony@atomide.com>
*/
#include <linux/console.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/types.h>
#include <asm/errno.h>
#include "console_cmdline.h"
/*
* Allow longer DEVNAME:0.0 style console naming such as abcd0000.serial:0.0
* in addition to the legacy ttyS0 style naming.
*/
#define CONSOLE_NAME_MAX 32
#define CONSOLE_OPT_MAX 16
#define CONSOLE_BRL_OPT_MAX 16
struct console_option {
char name[CONSOLE_NAME_MAX];
char opt[CONSOLE_OPT_MAX];
char brl_opt[CONSOLE_BRL_OPT_MAX];
u8 has_brl_opt:1;
};
/* Updated only at console_setup() time, no locking needed */
static struct console_option conopt[MAX_CMDLINECONSOLES];
/**
* console_opt_save - Saves kernel command line console option for driver use
* @str: Kernel command line console name and option
* @brl_opt: Braille console options
*
* Saves a kernel command line console option for driver subsystems to use for
* adding a preferred console during init. Called from console_setup() only.
*
* Return: 0 on success, negative error code on failure.
*/
int __init console_opt_save(const char *str, const char *brl_opt)
{
struct console_option *con;
size_t namelen, optlen;
const char *opt;
int i;
namelen = strcspn(str, ",");
if (namelen == 0 || namelen >= CONSOLE_NAME_MAX)
return -EINVAL;
opt = str + namelen;
if (*opt == ',')
opt++;
optlen = strlen(opt);
if (optlen >= CONSOLE_OPT_MAX)
return -EINVAL;
for (i = 0; i < MAX_CMDLINECONSOLES; i++) {
con = &conopt[i];
if (con->name[0]) {
if (!strncmp(str, con->name, namelen))
return 0;
continue;
}
/*
* The name isn't terminated, only opt is. Empty opt is fine,
* but brl_opt can be either empty or NULL. For more info, see
* _braille_console_setup().
*/
strscpy(con->name, str, namelen + 1);
strscpy(con->opt, opt, CONSOLE_OPT_MAX);
if (brl_opt) {
strscpy(con->brl_opt, brl_opt, CONSOLE_BRL_OPT_MAX);
con->has_brl_opt = 1;
}
return 0;
}
return -ENOMEM;
}
static struct console_option *console_opt_find(const char *name)
{
struct console_option *con;
int i;
for (i = 0; i < MAX_CMDLINECONSOLES; i++) {
con = &conopt[i];
if (!strcmp(name, con->name))
return con;
}
return NULL;
}
/**
* add_preferred_console_match - Adds a preferred console if a match is found
* @match: Expected console on kernel command line, such as console=DEVNAME:0.0
* @name: Name of the console character device to add such as ttyS
* @idx: Index for the console
*
* Allows driver subsystems to add a console after translating the command
* line name to the character device name used for the console. Options are
* added automatically based on the kernel command line. Duplicate preferred
* consoles are ignored by __add_preferred_console().
*
* Return: 0 on success, negative error code on failure.
*/
int add_preferred_console_match(const char *match, const char *name,
const short idx)
{
struct console_option *con;
char *brl_opt = NULL;
if (!match || !strlen(match) || !name || !strlen(name) ||
idx < 0)
return -EINVAL;
con = console_opt_find(match);
if (!con)
return -ENOENT;
/*
* See __add_preferred_console(). It checks for NULL brl_options to set
* the preferred_console flag. Empty brl_opt instead of NULL leads into
* the preferred_console flag not set, and CON_CONSDEV not being set,
* and the boot console won't get disabled at the end of console_setup().
*/
if (con->has_brl_opt)
brl_opt = con->brl_opt;
console_opt_add_preferred_console(name, idx, con->opt, brl_opt);
return 0;
}
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