fbcon: Move fbcon callbacks into struct fbcon_bitops

Depending on rotation settings, fbcon sets different callback
functions in struct fbcon_par from within fbcon_set_bitops(). Declare
the callback functions in the new type struct fbcon_bitops. Then
only replace the single bitops pointer in struct fbcon_par.

Keeping callbacks in constant instances of struct fbcon_bitops
makes it harder to exploit the callbacks. Also makes the code slightly
easier to maintain.

For tile-based consoles, there's a separate instance of the bitops
structure.

Signed-off-by: Thomas Zimmermann <[e-mail]>
Reviewed-by: Sam Ravnborg <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/video/fbdev/core/bitblit.c

···
 	return err;
 }
 
+static const struct fbcon_bitops bit_fbcon_bitops = {
+	.bmove = bit_bmove,
+	.clear = bit_clear,
+	.putcs = bit_putcs,
+	.clear_margins = bit_clear_margins,
+	.cursor = bit_cursor,
+	.update_start = bit_update_start,
+};
+
 void fbcon_set_bitops(struct fbcon_par *par)
 {
-	par->bmove = bit_bmove;
-	par->clear = bit_clear;
-	par->putcs = bit_putcs;
-	par->clear_margins = bit_clear_margins;
-	par->cursor = bit_cursor;
-	par->update_start = bit_update_start;
-	par->rotate_font = NULL;
+	par->bitops = &bit_fbcon_bitops;
 
 	if (par->rotate)
 		fbcon_set_rotate(par);

drivers/video/fbdev/core/fbcon.c

···
 
 	c = scr_readw((u16 *) vc->vc_pos);
 	enable = par->cursor_flash && !par->cursor_state.enable;
-	par->cursor(vc, info, enable,
-		    get_fg_color(vc, info, c),
-		    get_bg_color(vc, info, c));
+	par->bitops->cursor(vc, info, enable,
+			    get_fg_color(vc, info, c),
+			    get_bg_color(vc, info, c));
 	console_unlock();
 
 	queue_delayed_work(system_power_efficient_wq, &par->cursor_work,
···
 	if (logo)
 		fbcon_prepare_logo(vc, info, cols, rows, new_cols, new_rows);
 
-	if (par->rotate_font && par->rotate_font(info, vc)) {
+	if (par->bitops->rotate_font && par->bitops->rotate_font(info, vc)) {
 		par->rotate = FB_ROTATE_UR;
 		set_blitting_type(vc, info);
 	}
···
 	y_break = p->vrows - p->yscroll;
 	if (sy < y_break && sy + height - 1 >= y_break) {
 		u_int b = y_break - sy;
-		par->clear(vc, info, real_y(p, sy), sx, b, width, fg, bg);
-		par->clear(vc, info, real_y(p, sy + b), sx, height - b, width, fg, bg);
+		par->bitops->clear(vc, info, real_y(p, sy), sx, b, width, fg, bg);
+		par->bitops->clear(vc, info, real_y(p, sy + b), sx, height - b,
+				     width, fg, bg);
 	} else
-		par->clear(vc, info, real_y(p, sy), sx, height, width, fg, bg);
+		par->bitops->clear(vc, info, real_y(p, sy), sx, height, width, fg, bg);
 }
 
 static void fbcon_clear(struct vc_data *vc, unsigned int sy, unsigned int sx,
···
 	struct fbcon_par *par = info->fbcon_par;
 
 	if (fbcon_is_active(vc, info))
-		par->putcs(vc, info, s, count, real_y(p, ypos), xpos,
-			   get_fg_color(vc, info, scr_readw(s)),
-			   get_bg_color(vc, info, scr_readw(s)));
+		par->bitops->putcs(vc, info, s, count, real_y(p, ypos), xpos,
+				   get_fg_color(vc, info, scr_readw(s)),
+				   get_bg_color(vc, info, scr_readw(s)));
 }
 
 static void fbcon_clear_margins(struct vc_data *vc, int bottom_only)
···
 	struct fbcon_par *par = info->fbcon_par;
 
 	if (fbcon_is_active(vc, info))
-		par->clear_margins(vc, info, margin_color, bottom_only);
+		par->bitops->clear_margins(vc, info, margin_color, bottom_only);
 }
 
 static void fbcon_cursor(struct vc_data *vc, bool enable)
···
 
 	par->cursor_flash = enable;
 
-	if (!par->cursor)
+	if (!par->bitops->cursor)
 		return;
 
-	par->cursor(vc, info, enable,
-		    get_fg_color(vc, info, c),
-		    get_bg_color(vc, info, c));
+	par->bitops->cursor(vc, info, enable,
+			    get_fg_color(vc, info, c),
+			    get_bg_color(vc, info, c));
 }
 
 static int scrollback_phys_max = 0;
···
 	par->var.xoffset = 0;
 	par->var.yoffset = p->yscroll * vc->vc_font.height;
 	par->var.vmode |= FB_VMODE_YWRAP;
-	par->update_start(info);
+	par->bitops->update_start(info);
 	scrollback_max += count;
 	if (scrollback_max > scrollback_phys_max)
 		scrollback_max = scrollback_phys_max;
···
 	par->var.xoffset = 0;
 	par->var.yoffset = p->yscroll * vc->vc_font.height;
 	par->var.vmode |= FB_VMODE_YWRAP;
-	par->update_start(info);
+	par->bitops->update_start(info);
 	scrollback_max -= count;
 	if (scrollback_max < 0)
 		scrollback_max = 0;
···
 
 	p->yscroll += count;
 	if (p->yscroll > p->vrows - vc->vc_rows) {
-		par->bmove(vc, info, p->vrows - vc->vc_rows,
-			    0, 0, 0, vc->vc_rows, vc->vc_cols);
+		par->bitops->bmove(vc, info, p->vrows - vc->vc_rows,
+				   0, 0, 0, vc->vc_rows, vc->vc_cols);
 		p->yscroll -= p->vrows - vc->vc_rows;
 	}
 
 	par->var.xoffset = 0;
 	par->var.yoffset = p->yscroll * vc->vc_font.height;
 	par->var.vmode &= ~FB_VMODE_YWRAP;
-	par->update_start(info);
+	par->bitops->update_start(info);
 	fbcon_clear_margins(vc, 1);
 	scrollback_max += count;
 	if (scrollback_max > scrollback_phys_max)
···
 	par->var.xoffset = 0;
 	par->var.yoffset = p->yscroll * vc->vc_font.height;
 	par->var.vmode &= ~FB_VMODE_YWRAP;
-	par->update_start(info);
+	par->bitops->update_start(info);
 	fbcon_clear_margins(vc, 1);
 	scrollback_max += count;
 	if (scrollback_max > scrollback_phys_max)
···
 
 	p->yscroll -= count;
 	if (p->yscroll < 0) {
-		par->bmove(vc, info, 0, 0, p->vrows - vc->vc_rows,
-			    0, vc->vc_rows, vc->vc_cols);
+		par->bitops->bmove(vc, info, 0, 0, p->vrows - vc->vc_rows,
+				   0, vc->vc_rows, vc->vc_cols);
 		p->yscroll += p->vrows - vc->vc_rows;
 	}
 
 	par->var.xoffset = 0;
 	par->var.yoffset = p->yscroll * vc->vc_font.height;
 	par->var.vmode &= ~FB_VMODE_YWRAP;
-	par->update_start(info);
+	par->bitops->update_start(info);
 	fbcon_clear_margins(vc, 1);
 	scrollback_max -= count;
 	if (scrollback_max < 0)
···
 	par->var.xoffset = 0;
 	par->var.yoffset = p->yscroll * vc->vc_font.height;
 	par->var.vmode &= ~FB_VMODE_YWRAP;
-	par->update_start(info);
+	par->bitops->update_start(info);
 	fbcon_clear_margins(vc, 1);
 	scrollback_max -= count;
 	if (scrollback_max < 0)
···
 
 			if (c == scr_readw(d)) {
 				if (s > start) {
-					par->bmove(vc, info, line + ycount, x,
-						   line, x, 1, s - start);
+					par->bitops->bmove(vc, info, line + ycount, x,
+							   line, x, 1, s - start);
 					x += s - start + 1;
 					start = s + 1;
 				} else {
···
 			d++;
 		} while (s < le);
 		if (s > start)
-			par->bmove(vc, info, line + ycount, x, line, x, 1, s - start);
+			par->bitops->bmove(vc, info, line + ycount, x, line, x, 1,
+					     s - start);
 		console_conditional_schedule();
 		if (ycount > 0)
 			line++;
···
 		}
 		return;
 	}
-	par->bmove(vc, info, real_y(p, sy), sx, real_y(p, dy), dx, height, width);
+	par->bitops->bmove(vc, info, real_y(p, sy), sx, real_y(p, dy), dx,
+			     height, width);
 }
 
 static void fbcon_bmove(struct vc_data *vc, int sy, int sx, int dy, int dx,
···
 	set_blitting_type(vc, info);
 	par->cursor_reset = 1;
 
-	if (par->rotate_font && par->rotate_font(info, vc)) {
+	if (par->bitops->rotate_font && par->bitops->rotate_font(info, vc)) {
 		par->rotate = FB_ROTATE_UR;
 		set_blitting_type(vc, info);
 	}
···
 
 	if (fbcon_is_active(vc, info)) {
 		par->var.xoffset = par->var.yoffset = p->yscroll = 0;
-		par->update_start(info);
+		par->bitops->update_start(info);
 	}
 
 	fbcon_set_palette(vc, color_table);
···
 
 		if (fbcon_is_active(vc, info)) {
 			par->var.xoffset = par->var.yoffset = p->yscroll = 0;
-			par->update_start(info);
+			par->bitops->update_start(info);
 		}
 
 		fbcon_set_palette(vc, color_table);

drivers/video/fbdev/core/fbcon.h

···
     const struct fb_videomode *mode;
 };
 
-struct fbcon_par {
+struct fbcon_bitops {
 	void (*bmove)(struct vc_data *vc, struct fb_info *info, int sy,
 		      int sx, int dy, int dx, int height, int width);
 	void (*clear)(struct vc_data *vc, struct fb_info *info, int sy,
···
 		       bool enable, int fg, int bg);
 	int  (*update_start)(struct fb_info *info);
 	int  (*rotate_font)(struct fb_info *info, struct vc_data *vc);
+};
+
+struct fbcon_par {
 	struct fb_var_screeninfo var;  /* copy of the current fb_var_screeninfo */
 	struct delayed_work cursor_work; /* Cursor timer */
 	struct fb_cursor cursor_state;
···
 	u8    *cursor_src;
 	u32    cursor_size;
 	u32    fd_size;
+
+	const struct fbcon_bitops *bitops;
 };
 
     /*

drivers/video/fbdev/core/fbcon_ccw.c

···
 	return err;
 }
 
+static const struct fbcon_bitops ccw_fbcon_bitops = {
+	.bmove = ccw_bmove,
+	.clear = ccw_clear,
+	.putcs = ccw_putcs,
+	.clear_margins = ccw_clear_margins,
+	.cursor = ccw_cursor,
+	.update_start = ccw_update_start,
+	.rotate_font = fbcon_rotate_font,
+};
+
 void fbcon_rotate_ccw(struct fbcon_par *par)
 {
-	par->bmove = ccw_bmove;
-	par->clear = ccw_clear;
-	par->putcs = ccw_putcs;
-	par->clear_margins = ccw_clear_margins;
-	par->cursor = ccw_cursor;
-	par->update_start = ccw_update_start;
-	par->rotate_font = fbcon_rotate_font;
+	par->bitops = &ccw_fbcon_bitops;
 }

drivers/video/fbdev/core/fbcon_cw.c

···
 	return err;
 }
 
+static const struct fbcon_bitops cw_fbcon_bitops = {
+	.bmove = cw_bmove,
+	.clear = cw_clear,
+	.putcs = cw_putcs,
+	.clear_margins = cw_clear_margins,
+	.cursor = cw_cursor,
+	.update_start = cw_update_start,
+	.rotate_font = fbcon_rotate_font,
+};
+
 void fbcon_rotate_cw(struct fbcon_par *par)
 {
-	par->bmove = cw_bmove;
-	par->clear = cw_clear;
-	par->putcs = cw_putcs;
-	par->clear_margins = cw_clear_margins;
-	par->cursor = cw_cursor;
-	par->update_start = cw_update_start;
-	par->rotate_font = fbcon_rotate_font;
+	par->bitops = &cw_fbcon_bitops;
 }

drivers/video/fbdev/core/fbcon_ud.c

···
 	return err;
 }
 
+static const struct fbcon_bitops ud_fbcon_bitops = {
+	.bmove = ud_bmove,
+	.clear = ud_clear,
+	.putcs = ud_putcs,
+	.clear_margins = ud_clear_margins,
+	.cursor = ud_cursor,
+	.update_start = ud_update_start,
+	.rotate_font = fbcon_rotate_font,
+};
+
 void fbcon_rotate_ud(struct fbcon_par *par)
 {
-	par->bmove = ud_bmove;
-	par->clear = ud_clear;
-	par->putcs = ud_putcs;
-	par->clear_margins = ud_clear_margins;
-	par->cursor = ud_cursor;
-	par->update_start = ud_update_start;
-	par->rotate_font = fbcon_rotate_font;
+	par->bitops = &ud_fbcon_bitops;
 }

drivers/video/fbdev/core/tileblit.c

···
 	return err;
 }
 
+static const struct fbcon_bitops tile_fbcon_bitops = {
+	.bmove = tile_bmove,
+	.clear = tile_clear,
+	.putcs = tile_putcs,
+	.clear_margins = tile_clear_margins,
+	.cursor = tile_cursor,
+	.update_start = tile_update_start,
+};
+
 void fbcon_set_tileops(struct vc_data *vc, struct fb_info *info)
 {
 	struct fb_tilemap map;
 	struct fbcon_par *par = info->fbcon_par;
 
-	par->bmove = tile_bmove;
-	par->clear = tile_clear;
-	par->putcs = tile_putcs;
-	par->clear_margins = tile_clear_margins;
-	par->cursor = tile_cursor;
-	par->update_start = tile_update_start;
+	par->bitops = &tile_fbcon_bitops;
 
 	if (par->p) {
 		map.width = vc->vc_font.width;