video/fbdev: Always built-in video= cmdline parsing

In drm/i915 we want to get at the video= cmdline modes even when we
don't have fbdev support enabled, so that users can always override
the kernel's initial mode selection.

But that gives us a direct depency upon the parsing code in the fbdev
subsystem. Since it's so little code just extract these 2 functions
and always build them in.

Whiel at it fix the checkpatch fail in this code.

v2: Also move fb_mode_option. Spotted by the kbuild.

v3: Review from Geert:
- Keep the old copyright notice from fb_mem.c, although I have no
idea what exactly applies.
- Only compile this when needed.

Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: linux-fbdev@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

--

I prefer if we can merge this through drm-next since we'll use it
there in follow-up patches.
-Daniel

1 files changed, 110 insertions, 0 deletions

diff --git a/drivers/video/fbdev/core/fb_cmdline.c b/drivers/video/fbdev/core/fb_cmdline.c
new file mode 100644
index 000000000000..39509ccd92f1
--- /dev/null
+++ b/drivers/video/fbdev/core/fb_cmdline.c
@@ -0,0 +1,110 @@
+/*
+ *  linux/drivers/video/fb_cmdline.c
+ *
+ *  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:
+ *    Vetter <danie.vetter@ffwll.ch>
+ */
+#include <linux/init.h>
+#include <linux/fb.h>
+
+static char *video_options[FB_MAX] __read_mostly;
+static int ofonly __read_mostly;
+
+const char *fb_mode_option;
+EXPORT_SYMBOL_GPL(fb_mode_option);
+
+/**
+ * fb_get_options - get kernel boot parameters
+ * @name:   framebuffer name as it would appear in
+ *          the boot parameter line
+ *          (video=<name>:<options>)
+ * @option: the option will be stored here
+ *
+ * NOTE: Needed to maintain backwards compatibility
+ */
+int fb_get_options(const char *name, char **option)
+{
+	char *opt, *options = NULL;
+	int retval = 0;
+	int name_len = strlen(name), i;
+
+	if (name_len && ofonly && strncmp(name, "offb", 4))
+		retval = 1;
+
+	if (name_len && !retval) {
+		for (i = 0; i < FB_MAX; i++) {
+			if (video_options[i] == NULL)
+				continue;
+			if (!video_options[i][0])
+				continue;
+			opt = video_options[i];
+			if (!strncmp(name, opt, name_len) &&
+			    opt[name_len] == ':')
+				options = opt + name_len + 1;
+		}
+	}
+	/* No match, pass global option */
+	if (!options && option && fb_mode_option)
+		options = kstrdup(fb_mode_option, GFP_KERNEL);
+	if (options && !strncmp(options, "off", 3))
+		retval = 1;
+
+	if (option)
+		*option = options;
+
+	return retval;
+}
+EXPORT_SYMBOL(fb_get_options);
+
+/**
+ *	video_setup - process command line options
+ *	@options: string of options
+ *
+ *	Process command line options for frame buffer subsystem.
+ *
+ *	NOTE: This function is a __setup and __init function.
+ *            It only stores the options.  Drivers have to call
+ *            fb_get_options() as necessary.
+ *
+ *	Returns zero.
+ *
+ */
+static int __init video_setup(char *options)
+{
+	int i, global = 0;
+
+	if (!options || !*options)
+		global = 1;
+
+	if (!global && !strncmp(options, "ofonly", 6)) {
+		ofonly = 1;
+		global = 1;
+	}
+
+	if (!global && !strchr(options, ':')) {
+		fb_mode_option = options;
+		global = 1;
+	}
+
+	if (!global) {
+		for (i = 0; i < FB_MAX; i++) {
+			if (video_options[i] == NULL) {
+				video_options[i] = options;
+				break;
+			}
+		}
+	}
+
+	return 1;
+}
+__setup("video=", video_setup);