modedb.c

Linux环境下视频显示卡设备的驱动程序源代码

	mode->hsync_len = var->hsync_len;
	mode->vsync_len = var->vsync_len;
	mode->left_margin = var->left_margin;
	mode->right_margin = var->right_margin;
	mode->upper_margin = var->upper_margin;
	mode->lower_margin = var->lower_margin;
	mode->sync = var->sync;
	mode->vmode = var->vmode & FB_VMODE_MASK;
	mode->flag = FB_MODE_IS_FROM_VAR;
	mode->refresh = 0;

	if (!var->pixclock)
		return;

	pixclock = PICOS2KHZ(var->pixclock) * 1000;

	htotal = var->xres + var->right_margin + var->hsync_len +
		var->left_margin;
	vtotal = var->yres + var->lower_margin + var->vsync_len +
		var->upper_margin;

	if (var->vmode & FB_VMODE_INTERLACED)
		vtotal /= 2;
	if (var->vmode & FB_VMODE_DOUBLE)
		vtotal *= 2;

	hfreq = pixclock/htotal;
	mode->refresh = hfreq/vtotal;
}

/**
 * fb_videomode_to_var - convert fb_videomode to fb_var_screeninfo
 * @var: pointer to struct fb_var_screeninfo
 * @mode: pointer to struct fb_videomode
 */
void fb_videomode_to_var(struct fb_var_screeninfo *var,
			 const struct fb_videomode *mode)
{
	var->xres = mode->xres;
	var->yres = mode->yres;
	var->xres_virtual = mode->xres;
	var->yres_virtual = mode->yres;
	var->xoffset = 0;
	var->yoffset = 0;
	var->pixclock = mode->pixclock;
	var->left_margin = mode->left_margin;
	var->right_margin = mode->right_margin;
	var->upper_margin = mode->upper_margin;
	var->lower_margin = mode->lower_margin;
	var->hsync_len = mode->hsync_len;
	var->vsync_len = mode->vsync_len;
	var->sync = mode->sync;
	var->vmode = mode->vmode & FB_VMODE_MASK;
}

/**
 * fb_mode_is_equal - compare 2 videomodes
 * @mode1: first videomode
 * @mode2: second videomode
 *
 * RETURNS:
 * 1 if equal, 0 if not
 */
int fb_mode_is_equal(const struct fb_videomode *mode1,
		     const struct fb_videomode *mode2)
{
	return (mode1->xres         == mode2->xres &&
		mode1->yres         == mode2->yres &&
		mode1->pixclock     == mode2->pixclock &&
		mode1->hsync_len    == mode2->hsync_len &&
		mode1->vsync_len    == mode2->vsync_len &&
		mode1->left_margin  == mode2->left_margin &&
		mode1->right_margin == mode2->right_margin &&
		mode1->upper_margin == mode2->upper_margin &&
		mode1->lower_margin == mode2->lower_margin &&
		mode1->sync         == mode2->sync &&
		mode1->vmode        == mode2->vmode);
}

/**
 * fb_find_best_mode - find best matching videomode
 * @var: pointer to struct fb_var_screeninfo
 * @head: pointer to struct list_head of modelist
 *
 * RETURNS:
 * struct fb_videomode, NULL if none found
 *
 * IMPORTANT:
 * This function assumes that all modelist entries in
 * info->modelist are valid.
 *
 * NOTES:
 * Finds best matching videomode which has an equal or greater dimension than
 * var->xres and var->yres.  If more than 1 videomode is found, will return
 * the videomode with the highest refresh rate
 */
const struct fb_videomode *fb_find_best_mode(const struct fb_var_screeninfo *var,
					     struct list_head *head)
{
	struct list_head *pos;
	struct fb_modelist *modelist;
	struct fb_videomode *mode, *best = NULL;
	u32 diff = -1;

	list_for_each(pos, head) {
		u32 d;

		modelist = list_entry(pos, struct fb_modelist, list);
		mode = &modelist->mode;

		if (mode->xres >= var->xres && mode->yres >= var->yres) {
			d = (mode->xres - var->xres) +
				(mode->yres - var->yres);
			if (diff > d) {
				diff = d;
				best = mode;
			} else if (diff == d && best &&
				   mode->refresh > best->refresh)
				best = mode;
		}
	}
	return best;
}

/**
 * fb_find_nearest_mode - find closest videomode
 *
 * @mode: pointer to struct fb_videomode
 * @head: pointer to modelist
 *
 * Finds best matching videomode, smaller or greater in dimension.
 * If more than 1 videomode is found, will return the videomode with
 * the closest refresh rate.
 */
const struct fb_videomode *fb_find_nearest_mode(const struct fb_videomode *mode,
					        struct list_head *head)
{
	struct list_head *pos;
	struct fb_modelist *modelist;
	struct fb_videomode *cmode, *best = NULL;
	u32 diff = -1, diff_refresh = -1;

	list_for_each(pos, head) {
		u32 d;

		modelist = list_entry(pos, struct fb_modelist, list);
		cmode = &modelist->mode;

		d = abs(cmode->xres - mode->xres) +
			abs(cmode->yres - mode->yres);
		if (diff > d) {
			diff = d;
			best = cmode;
		} else if (diff == d) {
			d = abs(cmode->refresh - mode->refresh);
			if (diff_refresh > d) {
				diff_refresh = d;
				best = cmode;
			}
		}
	}

	return best;
}

/**
 * fb_match_mode - find a videomode which exactly matches the timings in var
 * @var: pointer to struct fb_var_screeninfo
 * @head: pointer to struct list_head of modelist
 *
 * RETURNS:
 * struct fb_videomode, NULL if none found
 */
const struct fb_videomode *fb_match_mode(const struct fb_var_screeninfo *var,
					 struct list_head *head)
{
	struct list_head *pos;
	struct fb_modelist *modelist;
	struct fb_videomode *m, mode;

	fb_var_to_videomode(&mode, var);
	list_for_each(pos, head) {
		modelist = list_entry(pos, struct fb_modelist, list);
		m = &modelist->mode;
		if (fb_mode_is_equal(m, &mode))
			return m;
	}
	return NULL;
}

/**
 * fb_add_videomode: adds videomode entry to modelist
 * @mode: videomode to add
 * @head: struct list_head of modelist
 *
 * NOTES:
 * Will only add unmatched mode entries
 */
int fb_add_videomode(const struct fb_videomode *mode, struct list_head *head)
{
	struct list_head *pos;
	struct fb_modelist *modelist;
	struct fb_videomode *m;
	int found = 0;

	list_for_each(pos, head) {
		modelist = list_entry(pos, struct fb_modelist, list);
		m = &modelist->mode;
		if (fb_mode_is_equal(m, mode)) {
			found = 1;
			break;
		}
	}
	if (!found) {
		modelist = kmalloc(sizeof(struct fb_modelist),
						  GFP_KERNEL);

		if (!modelist)
			return -ENOMEM;
		modelist->mode = *mode;
		list_add(&modelist->list, head);
	}
	return 0;
}

/**
 * fb_delete_videomode: removed videomode entry from modelist
 * @mode: videomode to remove
 * @head: struct list_head of modelist
 *
 * NOTES:
 * Will remove all matching mode entries
 */
void fb_delete_videomode(const struct fb_videomode *mode,
			 struct list_head *head)
{
	struct list_head *pos, *n;
	struct fb_modelist *modelist;
	struct fb_videomode *m;

	list_for_each_safe(pos, n, head) {
		modelist = list_entry(pos, struct fb_modelist, list);
		m = &modelist->mode;
		if (fb_mode_is_equal(m, mode)) {
			list_del(pos);
			kfree(pos);
		}
	}
}

/**
 * fb_destroy_modelist: destroy modelist
 * @head: struct list_head of modelist
 */
void fb_destroy_modelist(struct list_head *head)
{
	struct list_head *pos, *n;

	list_for_each_safe(pos, n, head) {
		list_del(pos);
		kfree(pos);
	}
}
EXPORT_SYMBOL_GPL(fb_destroy_modelist);

/**
 * fb_videomode_to_modelist: convert mode array to mode list
 * @modedb: array of struct fb_videomode
 * @num: number of entries in array
 * @head: struct list_head of modelist
 */
void fb_videomode_to_modelist(const struct fb_videomode *modedb, int num,
			      struct list_head *head)
{
	int i;

	INIT_LIST_HEAD(head);

	for (i = 0; i < num; i++) {
		if (fb_add_videomode(&modedb[i], head))
			return;
	}
}

const struct fb_videomode *fb_find_best_display(const struct fb_monspecs *specs,
					        struct list_head *head)
{
	struct list_head *pos;
	struct fb_modelist *modelist;
	const struct fb_videomode *m, *m1 = NULL, *md = NULL, *best = NULL;
	int first = 0;

	if (!head->prev || !head->next || list_empty(head))
		goto finished;

	/* get the first detailed mode and the very first mode */
	list_for_each(pos, head) {
		modelist = list_entry(pos, struct fb_modelist, list);
		m = &modelist->mode;

		if (!first) {
			m1 = m;
			first = 1;
		}

		if (m->flag & FB_MODE_IS_FIRST) {
 			md = m;
			break;
		}
	}

	/* first detailed timing is preferred */
	if (specs->misc & FB_MISC_1ST_DETAIL) {
		best = md;
		goto finished;
	}

	/* find best mode based on display width and height */
	if (specs->max_x && specs->max_y) {
		struct fb_var_screeninfo var;

		memset(&var, 0, sizeof(struct fb_var_screeninfo));
		var.xres = (specs->max_x * 7200)/254;
		var.yres = (specs->max_y * 7200)/254;
		m = fb_find_best_mode(&var, head);
		if (m) {
			best = m;
			goto finished;
		}
	}

	/* use first detailed mode */
	if (md) {
		best = md;
		goto finished;
	}

	/* last resort, use the very first mode */
	best = m1;
finished:
	return best;
}
EXPORT_SYMBOL(fb_find_best_display);

EXPORT_SYMBOL(fb_videomode_to_var);
EXPORT_SYMBOL(fb_var_to_videomode);
EXPORT_SYMBOL(fb_mode_is_equal);
EXPORT_SYMBOL(fb_add_videomode);
EXPORT_SYMBOL(fb_match_mode);
EXPORT_SYMBOL(fb_find_best_mode);
EXPORT_SYMBOL(fb_find_nearest_mode);
EXPORT_SYMBOL(fb_videomode_to_modelist);
EXPORT_SYMBOL(fb_find_mode);