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