path: root/drivers/gpu/drm/drm_fb_helper.c

/*
 * Copyright (c) 2006-2009 Red Hat Inc.
 * Copyright (c) 2006-2008 Intel Corporation
 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
 *
 * DRM framebuffer helper functions
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 *
 * Authors:
 *      Dave Airlie <airlied@linux.ie>
 *      Jesse Barnes <jesse.barnes@intel.com>
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/sysrq.h>
#include <linux/slab.h>
#include <linux/fb.h>
#include <linux/module.h>
#include <drm/drmP.h>
#include <drm/drm_crtc.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_crtc_helper.h>

MODULE_AUTHOR("David Airlie, Jesse Barnes");
MODULE_DESCRIPTION("DRM KMS helper");
MODULE_LICENSE("GPL and additional rights");

static LIST_HEAD(kernel_fb_helper_list);

/**
 * DOC: fbdev helpers
 *
 * The fb helper functions are useful to provide an fbdev on top of a drm kernel
 * mode setting driver. They can be used mostly independantely from the crtc
 * helper functions used by many drivers to implement the kernel mode setting
 * interfaces.
 *
 * Initialization is done as a three-step process with drm_fb_helper_init(),
 * drm_fb_helper_single_add_all_connectors() and drm_fb_helper_initial_config().
 * Drivers with fancier requirements than the default beheviour can override the
 * second step with their own code.  Teardown is done with drm_fb_helper_fini().
 *
 * At runtime drivers should restore the fbdev console by calling
 * drm_fb_helper_restore_fbdev_mode() from their ->lastclose callback. They
 * should also notify the fb helper code from updates to the output
 * configuration by calling drm_fb_helper_hotplug_event(). For easier
 * integration with the output polling code in drm_crtc_helper.c the modeset
 * code proves a ->output_poll_changed callback.
 *
 * All other functions exported by the fb helper library can be used to
 * implement the fbdev driver interface by the driver.
 */

/**
 * drm_fb_helper_single_add_all_connectors() - add all connectors to fbdev
 * 					       emulation helper
 * @fb_helper: fbdev initialized with drm_fb_helper_init
 *
 * This functions adds all the available connectors for use with the given
 * fb_helper. This is a separate step to allow drivers to freely assign
 * connectors to the fbdev, e.g. if some are reserved for special purposes or
 * not adequate to be used for the fbcon.
 *
 * Since this is part of the initial setup before the fbdev is published, no
 * locking is required.
 */
int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
{
	struct drm_device *dev = fb_helper->dev;
	struct drm_connector *connector;
	int i;

	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
		struct drm_fb_helper_connector *fb_helper_connector;

		fb_helper_connector = kzalloc(sizeof(struct drm_fb_helper_connector), GFP_KERNEL);
		if (!fb_helper_connector)
			goto fail;

		fb_helper_connector->connector = connector;
		fb_helper->connector_info[fb_helper->connector_count++] = fb_helper_connector;
	}
	return 0;
fail:
	for (i = 0; i < fb_helper->connector_count; i++) {
		kfree(fb_helper->connector_info[i]);
		fb_helper->connector_info[i] = NULL;
	}
	fb_helper->connector_count = 0;
	return -ENOMEM;
}
EXPORT_SYMBOL(drm_fb_helper_single_add_all_connectors);

static int drm_fb_helper_parse_command_line(struct drm_fb_helper *fb_helper)
{
	struct drm_fb_helper_connector *fb_helper_conn;
	int i;

	for (i = 0; i < fb_helper->connector_count; i++) {
		struct drm_cmdline_mode *mode;
		struct drm_connector *connector;
		char *option = NULL;

		fb_helper_conn = fb_helper->connector_info[i];
		connector = fb_helper_conn->connector;
		mode = &fb_helper_conn->cmdline_mode;

		/* do something on return - turn off connector maybe */
		if (fb_get_options(drm_get_connector_name(connector), &option))
			continue;

		if (drm_mode_parse_command_line_for_connector(option,
							      connector,