// 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);