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1// SPDX-License-Identifier: GPL-2.02/*3 * Based on the fbdev code in drivers/video/fbdev/core/fb_cmdline:4 *5 * Copyright (C) 2014 Intel Corp6 * Copyright (C) 1994 Martin Schaller7 *8 * 2001 - Documented with DocBook9 * - Brad Douglas <brad@neruo.com>10 *11 * This file is subject to the terms and conditions of the GNU General Public12 * License. See the file COPYING in the main directory of this archive13 * for more details.14 *15 * Authors:16 * Daniel Vetter <daniel.vetter@ffwll.ch>17 */18 19#include <linux/fb.h> /* for FB_MAX */20#include <linux/init.h>21 22#include <video/cmdline.h>23 24/*25 * FB_MAX is the maximum number of framebuffer devices and also26 * the maximum number of video= parameters. Although not directly27 * related to each other, it makes sense to keep it that way.28 */29static const char *video_options[FB_MAX] __read_mostly;30static const char *video_option __read_mostly;31static int video_of_only __read_mostly;32 33static const char *__video_get_option_string(const char *name)34{35 const char *options = NULL;36 size_t name_len = 0;37 38 if (name)39 name_len = strlen(name);40 41 if (name_len) {42 unsigned int i;43 const char *opt;44 45 for (i = 0; i < ARRAY_SIZE(video_options); ++i) {46 if (!video_options[i])47 continue;48 if (video_options[i][0] == '\0')49 continue;50 opt = video_options[i];51 if (!strncmp(opt, name, name_len) && opt[name_len] == ':')52 options = opt + name_len + 1;53 }54 }55 56 /* No match, return global options */57 if (!options)58 options = video_option;59 60 return options;61}62 63/**64 * video_get_options - get kernel boot parameters65 * @name: name of the output as it would appear in the boot parameter66 * line (video=<name>:<options>)67 *68 * Looks up the video= options for the given name. Names are connector69 * names with DRM, or driver names with fbdev. If no video option for70 * the name has been specified, the function returns the global video=71 * setting. A @name of NULL always returns the global video setting.72 *73 * Returns:74 * The string of video options for the given name, or NULL if no video75 * option has been specified.76 */77const char *video_get_options(const char *name)78{79 return __video_get_option_string(name);80}81EXPORT_SYMBOL(video_get_options);82 83#if IS_ENABLED(CONFIG_FB_CORE)84bool __video_get_options(const char *name, const char **options, bool is_of)85{86 bool enabled = true;87 const char *opt = NULL;88 89 if (video_of_only && !is_of)90 enabled = false;91 92 opt = __video_get_option_string(name);93 94 if (options)95 *options = opt;96 97 return enabled;98}99EXPORT_SYMBOL(__video_get_options);100#endif101 102/*103 * Process command line options for video adapters. This function is104 * a __setup and __init function. It only stores the options. Drivers105 * have to call video_get_options() as necessary.106 */107static int __init video_setup(char *options)108{109 if (!options || !*options)110 goto out;111 112 if (!strncmp(options, "ofonly", 6)) {113 video_of_only = true;114 goto out;115 }116 117 if (strchr(options, ':')) {118 /* named */119 size_t i;120 121 for (i = 0; i < ARRAY_SIZE(video_options); i++) {122 if (!video_options[i]) {123 video_options[i] = options;124 break;125 }126 }127 } else {128 /* global */129 video_option = options;130 }131 132out:133 return 1;134}135__setup("video=", video_setup);136