| 1 | |
| 2 | |
| 3 | * Based on the fbdev code in drivers/video/fbdev/core/fb_cmdline:
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| 4 | *
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| 5 | * Copyright (C) 2014 Intel Corp
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| 6 | * Copyright (C) 1994 Martin Schaller
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| 7 | *
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| 8 | * 2001 - Documented with DocBook
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| 9 | * - Brad Douglas <[email protected]>
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| 10 | *
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| 11 | * This file is subject to the terms and conditions of the GNU General Public
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| 12 | * License. See the file COPYING in the main directory of this archive
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| 13 | * for more details.
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| 14 | *
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| 15 | * Authors:
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| 16 | * Daniel Vetter <[email protected]>
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| 17 |
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| 18 |
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| 19 | #include <linux/fb.h>
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| 20 | #include <linux/init.h>
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| 21 |
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| 22 | #include <video/cmdline.h>
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| 23 |
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| 24 | |
| 25 | * FB_MAX is the maximum number of framebuffer devices and also
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| 26 | * the maximum number of video= parameters. Although not directly
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| 27 | * related to each other, it makes sense to keep it that way.
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| 28 |
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| 29 | static const char *video_options[FB_MAX] __read_mostly;
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| 30 | static const char *video_option __read_mostly;
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| 31 | static int video_of_only __read_mostly;
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| 32 |
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| 33 | static const char *__video_get_option_string(const char *name)
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| 34 | {
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| 35 | const char *options = NULL;
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| 36 | size_t name_len = 0;
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| 37 |
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| 38 | if (name)
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| 39 | name_len = strlen(name);
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| 40 |
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| 41 | if (name_len) {
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| 42 | unsigned int i;
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| 43 | const char *opt;
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| 44 |
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| 45 | for (i = 0; i < ARRAY_SIZE(video_options); ++i) {
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| 46 | if (!video_options[i])
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| 47 | continue;
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| 48 | if (video_options[i][0] == '\0')
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| 49 | continue;
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| 50 | opt = video_options[i];
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| 51 | if (!strncmp(opt, name, name_len) && opt[name_len] == ':')
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| 52 | options = opt + name_len + 1;
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| 53 | }
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| 54 | }
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| 55 |
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| 56 |
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| 57 | if (!options)
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| 58 | options = video_option;
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| 59 |
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| 60 | return options;
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| 61 | }
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| 62 |
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| 63 | |
| 64 | * video_get_options - get kernel boot parameters
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| 65 | * @name: name of the output as it would appear in the boot parameter
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| 66 | * line (video=<name>:<options>)
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| 67 | *
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| 68 | * Looks up the video= options for the given name. Names are connector
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| 69 | * names with DRM, or driver names with fbdev. If no video option for
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| 70 | * the name has been specified, the function returns the global video=
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| 71 | * setting. A @name of NULL always returns the global video setting.
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| 72 | *
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| 73 | * Returns:
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| 74 | * The string of video options for the given name, or NULL if no video
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| 75 | * option has been specified.
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| 76 |
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| 77 | const char *video_get_options(const char *name)
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| 78 | {
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| 79 | return __video_get_option_string(name);
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| 80 | }
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| 81 | EXPORT_SYMBOL(video_get_options);
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| 82 |
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| 83 | #if IS_ENABLED(CONFIG_FB_CORE)
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| 84 | bool __video_get_options(const char *name, const char **options, bool is_of)
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| 85 | {
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| 86 | bool enabled = true;
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| 87 | const char *opt = NULL;
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| 88 |
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| 89 | if (video_of_only && !is_of)
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| 90 | enabled = false;
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| 91 |
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| 92 | opt = __video_get_option_string(name);
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| 93 |
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| 94 | if (options)
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| 95 | *options = opt;
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| 96 |
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| 97 | return enabled;
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| 98 | }
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| 99 | EXPORT_SYMBOL(__video_get_options);
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| 100 | #endif
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| 101 |
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| 102 | |
| 103 | * Process command line options for video adapters. This function is
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| 104 | * a __setup and __init function. It only stores the options. Drivers
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| 105 | * have to call video_get_options() as necessary.
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| 106 |
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| 107 | static int __init video_setup(char *options)
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| 108 | {
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| 109 | if (!options || !*options)
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| 110 | goto out;
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| 111 |
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| 112 | if (!strncmp(options, "ofonly", 6)) {
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| 113 | video_of_only = true;
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| 114 | goto out;
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| 115 | }
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| 116 |
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| 117 | if (strchr(options, ':')) {
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| 118 |
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| 119 | size_t i;
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| 120 |
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| 121 | for (i = 0; i < ARRAY_SIZE(video_options); i++) {
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| 122 | if (!video_options[i]) {
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| 123 | video_options[i] = options;
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| 124 | break;
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| 125 | }
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| 126 | }
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| 127 | } else {
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| 128 |
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| 129 | video_option = options;
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| 130 | }
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| 131 |
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| 132 | out:
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| 133 | return 1;
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| 134 | }
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| 135 | __setup("video=", video_setup);
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