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// SPDX-License-Identifier: GPL-2.0
/*
* Based on the fbdev code in drivers/video/fbdev/core/fb_cmdline:
*
* Copyright (C) 2014 Intel Corp
* Copyright (C) 1994 Martin Schaller
*
* 2001 - Documented with DocBook
* - Brad Douglas <brad@neruo.com>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive
* for more details.
*
* Authors:
* Daniel Vetter <daniel.vetter@ffwll.ch>
*/
#include <linux/fb.h> /* for FB_MAX */
#include <linux/init.h>
#include <video/cmdline.h>
/*
* FB_MAX is the maximum number of framebuffer devices and also
* the maximum number of video= parameters. Although not directly
* related to each other, it makes sense to keep it that way.
*/
static const char *video_options[FB_MAX] __read_mostly;
static const char *video_option __read_mostly;
static int video_of_only __read_mostly;
static const char *__video_get_option_string(const char *name)
{
const char *options = NULL;
size_t name_len = 0;
if (name)
name_len = strlen(name);
if (name_len) {
unsigned int i;
const char *opt;
for (i = 0; i < ARRAY_SIZE(video_options); ++i) {
if (!video_options[i])
continue;
if (video_options[i][0] == '\0')
continue;
opt = video_options[i];
if (!strncmp(opt, name, name_len) && opt[name_len] == ':')
options = opt + name_len + 1;
}
}
/* No match, return global options */
if (!options)
options = video_option;
return options;
}
/**
* video_get_options - get kernel boot parameters
* @name: name of the output as it would appear in the boot parameter
* line (video=<name>:<options>)
*
* Looks up the video= options for the given name. Names are connector
* names with DRM, or driver names with fbdev. If no video option for
* the name has been specified, the function returns the global video=
* setting. A @name of NULL always returns the global video setting.
*
* Returns:
* The string of video options for the given name, or NULL if no video
* option has been specified.
*/
const char *video_get_options(const char *name)
{
return __video_get_option_string(name);
}
EXPORT_SYMBOL(video_get_options);
bool __video_get_options(const char *name, const char **options, bool is_of)
{
bool enabled = true;
const char *opt = NULL;
if (video_of_only && !is_of)
enabled = false;
opt = __video_get_option_string(name);
if (options)
*options = opt;
return enabled;
}
EXPORT_SYMBOL(__video_get_options);
/*
* Process command line options for video adapters. This function is
* a __setup and __init function. It only stores the options. Drivers
* have to call video_get_options() as necessary.
*/
static int __init video_setup(char *options)
{
if (!options || !*options)
goto out;
if (!strncmp(options, "ofonly", 6)) {
video_of_only = true;
goto out;
}
if (strchr(options, ':')) {
/* named */
size_t i;
for (i = 0; i < ARRAY_SIZE(video_options); i++) {
if (!video_options[i]) {
video_options[i] = options;
break;
}
}
} else {
/* global */
video_option = options;
}
out:
return 1;
}
__setup("video=", video_setup);
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