xref: /netbsd/sys/arch/sgimips/gio/light.c (revision 6550d01e)
1 /*	$Id: light.c,v 1.5 2007/03/04 06:00:39 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 2006 Stephen M. Rumble
5  * Copyright (c) 2003 Ilpo Ruotsalainen
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. The name of the author may not be used to endorse or promote products
17  *    derived from this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  *
30  * <<Id: LICENSE_GC,v 1.1 2001/10/01 23:24:05 cgd Exp>>
31  */
32 
33 /*
34  * SGI "Light" graphics, a.k.a. "Entry", "Starter", "LG1", and "LG2".
35  *
36  * 1024x768 8bpp at 60Hz.
37  *
38  * This driver supports the boards found in Indigo R3k and R4k machines.
39  * There is a Crimson variant, but the register offsets differ significantly.
40  *
41  * Light's REX chip is the precursor of the REX3 found in "newport", hence
42  * much similarity exists.
43  */
44 
45 #include <sys/cdefs.h>
46 __KERNEL_RCSID(0, "$NetBSD: light.c,v 1.5 2007/03/04 06:00:39 christos Exp $");
47 
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/device.h>
51 #include <sys/malloc.h>
52 
53 #include <machine/sysconf.h>
54 
55 #include <dev/wscons/wsconsio.h>
56 #include <dev/wscons/wsdisplayvar.h>
57 #include <dev/wsfont/wsfont.h>
58 
59 #include <sgimips/gio/giovar.h>
60 #include <sgimips/gio/lightvar.h>
61 #include <sgimips/gio/lightreg.h>
62 
63 struct light_softc {
64 	struct device sc_dev;
65 
66 	struct light_devconfig *sc_dc;
67 };
68 
69 struct light_devconfig {
70 	uint32_t		dc_addr;
71 
72 	bus_space_tag_t		dc_st;
73 	bus_space_handle_t	dc_sh;
74 
75 	int			dc_boardrev;
76 	int                     dc_font;
77 	struct wsdisplay_font  *dc_fontdata;
78 };
79 
80 /* always 1024x768x8 */
81 #define LIGHT_XRES	1024
82 #define LIGHT_YRES	768
83 #define LIGHT_DEPTH	8
84 
85 static int	light_match(struct device *, struct cfdata *, void *);
86 static void	light_attach(struct device *, struct device *, void *);
87 
88 CFATTACH_DECL(light, sizeof(struct light_softc), light_match, light_attach,
89     NULL, NULL);
90 
91 /* wsdisplay_emulops */
92 static void	light_cursor(void *, int, int, int);
93 static int	light_mapchar(void *, int, unsigned int *);
94 static void	light_putchar(void *, int, int, u_int, long);
95 static void	light_copycols(void *, int, int, int, int);
96 static void	light_erasecols(void *, int, int, int, long);
97 static void	light_copyrows(void *, int, int, int);
98 static void	light_eraserows(void *, int, int, long);
99 static int	light_allocattr(void *, int, int, int, long *);
100 
101 /* wsdisplay_accessops */
102 static int	light_ioctl(void *, void *, u_long, void *, int, struct lwp *);
103 static paddr_t	light_mmap(void *, void *, off_t, int);
104 static int	light_alloc_screen(void *, const struct wsscreen_descr *,
105     void **, int *, int *, long *);
106 static void	light_free_screen(void *, void *);
107 static int	light_show_screen(void *, void *, int,
108     void (*)(void *, int, int), void *);
109 
110 static const struct wsdisplay_accessops light_accessops = {
111 	.ioctl		= light_ioctl,
112 	.mmap		= light_mmap,
113 	.alloc_screen	= light_alloc_screen,
114 	.free_screen	= light_free_screen,
115 	.show_screen	= light_show_screen,
116 	.load_font	= NULL,
117 	.pollc		= NULL,
118 	.scroll		= NULL
119 };
120 
121 static const struct wsdisplay_emulops light_emulops = {
122 	.cursor		= light_cursor,
123 	.mapchar	= light_mapchar,
124 	.putchar	= light_putchar,
125 	.copycols	= light_copycols,
126 	.erasecols	= light_erasecols,
127 	.copyrows	= light_copyrows,
128 	.eraserows	= light_eraserows,
129 	.allocattr	= light_allocattr,
130 	.replaceattr	= NULL
131 };
132 
133 static const struct wsscreen_descr light_screen = {
134 	.name           = "1024x768",
135 	.ncols          = 128,
136 	.nrows          = 48,
137 	.textops        = &light_emulops,
138 	.fontwidth      = 8,
139 	.fontheight     = 16,
140 	.capabilities   = WSSCREEN_WSCOLORS | WSSCREEN_HILIT | WSSCREEN_REVERSE
141 };
142 
143 const struct wsscreen_descr *_light_screenlist[] = {
144 	&light_screen
145 };
146 
147 static const struct wsscreen_list light_screenlist = {
148 	sizeof(_light_screenlist) / sizeof(_light_screenlist[0]),
149 	_light_screenlist
150 };
151 
152 static struct light_devconfig	light_console_dc;
153 static int			light_is_console = 0;
154 
155 #define LIGHT_ATTR_ENCODE(fg, bg)	(((fg << 8) & 0xff00) | (bg * 0x00ff))
156 #define LIGHT_ATTR_FG(attr)		((attr >> 8) & 0x00ff)
157 #define LIGHT_ATTR_BG(attr)		(attr & 0x00ff)
158 
159 #define LIGHT_IS_LG1(_rev)		((_rev) < 2)	/* else LG2 */
160 
161 /*******************************************************************************
162  * REX routines and helper functions
163  ******************************************************************************/
164 
165 static uint32_t
166 rex_read(struct light_devconfig *dc, uint32_t rset, uint32_t r)
167 {
168 
169 	return (bus_space_read_4(dc->dc_st, dc->dc_sh, rset + r));
170 }
171 
172 static void
173 rex_write(struct light_devconfig *dc, uint32_t rset, uint32_t r, uint32_t v)
174 {
175 
176 	bus_space_write_4(dc->dc_st, dc->dc_sh, rset + r, v);
177 }
178 
179 static uint8_t
180 rex_vc1_read(struct light_devconfig *dc)
181 {
182 
183 	rex_write(dc, REX_PAGE1_GO, REX_P1REG_CFGSEL, REX_CFGSEL_VC1_SYSCTL);
184 	rex_read(dc, REX_PAGE1_GO, REX_P1REG_VC1_ADDRDATA);
185 	return (rex_read(dc, REX_PAGE1_SET, REX_P1REG_VC1_ADDRDATA));
186 }
187 
188 static void
189 rex_vc1_write(struct light_devconfig *dc, uint8_t val)
190 {
191 
192 	rex_write(dc, REX_PAGE1_GO, REX_P1REG_CFGSEL, REX_CFGSEL_VC1_SYSCTL);
193 	rex_write(dc, REX_PAGE1_SET, REX_P1REG_VC1_ADDRDATA, val);
194 	rex_write(dc, REX_PAGE1_GO, REX_P1REG_VC1_ADDRDATA, val);
195 }
196 
197 static void
198 rex_wait(struct light_devconfig *dc)
199 {
200 
201 	while (rex_read(dc, REX_PAGE1_SET,REX_P1REG_CFGMODE) & REX_CFGMODE_BUSY)
202 		;
203 }
204 
205 static int
206 rex_revision(struct light_devconfig *dc)
207 {
208 
209 	rex_write(dc, REX_PAGE1_SET, REX_P1REG_CFGSEL, REX_CFGSEL_VC1_LADDR);
210 	rex_read(dc, REX_PAGE1_GO, REX_P1REG_WCLOCKREV);
211 	return (rex_read(dc, REX_PAGE1_SET, REX_P1REG_WCLOCKREV) & 0x7);
212 }
213 
214 static void
215 rex_copy_rect(struct light_devconfig *dc, int from_x, int from_y, int to_x,
216     int to_y, int width, int height)
217 {
218 	int dx, dy, ystarti, yendi;
219 
220 	dx = from_x - to_x;
221 	dy = from_y - to_y;
222 
223 	/* adjust for y. NB: STOPONX, STOPONY are inclusive */
224 	if (to_y > from_y) {
225 		ystarti = to_y + height - 1;
226 		yendi = to_y;
227 	} else {
228 		ystarti = to_y;
229 		yendi = to_y + height - 1;
230 	}
231 
232 	rex_wait(dc);
233 
234 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_XSTARTI, to_x);
235 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_XENDI, to_x + width);
236 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_YSTARTI, ystarti);
237 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_YENDI, yendi);
238 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_COMMAND, REX_OP_DRAW |
239 	    REX_LOGICOP_SRC | REX_OP_FLG_LOGICSRC | REX_OP_FLG_QUADMODE |
240 	    REX_OP_FLG_BLOCK | REX_OP_FLG_STOPONX | REX_OP_FLG_STOPONY);
241 	rex_write(dc, REX_PAGE0_GO, REX_P0REG_XYMOVE,
242 	    ((dx << 16) & 0xffff0000) | (dy & 0x0000ffff));
243 }
244 
245 static void
246 rex_fill_rect(struct light_devconfig *dc, int from_x, int from_y, int to_x,
247     int to_y, long attr)
248 {
249 
250 	rex_wait(dc);
251 
252 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_YSTARTI, from_y);
253 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_YENDI, to_y);
254 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_XSTARTI, from_x);
255 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_XENDI, to_x);
256 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_COLORREDI, LIGHT_ATTR_BG(attr));
257 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_COMMAND, REX_OP_DRAW |
258 	    REX_LOGICOP_SRC | REX_OP_FLG_QUADMODE | REX_OP_FLG_BLOCK |
259 	    REX_OP_FLG_STOPONX | REX_OP_FLG_STOPONY);
260 	rex_read(dc, REX_PAGE0_GO, REX_P0REG_COMMAND);
261 }
262 
263 /*******************************************************************************
264  * match/attach functions
265  ******************************************************************************/
266 
267 static int
268 light_match(struct device *parent, struct cfdata *self, void *aux)
269 {
270 	struct gio_attach_args *ga = aux;
271 
272 	if (ga->ga_addr != LIGHT_ADDR_0 && ga->ga_addr != LIGHT_ADDR_1)
273 		return (0);
274 
275 	if (platform.badaddr(
276 	    (void *)(ga->ga_ioh + REX_PAGE1_SET + REX_P1REG_XYOFFSET),
277 	    sizeof(uint32_t)))
278 		return (0);
279 
280 	if (bus_space_read_4(ga->ga_iot, ga->ga_ioh,
281 	    REX_PAGE1_SET + REX_P1REG_XYOFFSET) != 0x08000800)
282 		return (0);
283 
284 	return (1);
285 }
286 
287 static void
288 light_attach_common(struct light_devconfig *dc, struct gio_attach_args *ga)
289 {
290 
291 	dc->dc_addr = ga->ga_addr;
292 	dc->dc_st = ga->ga_iot;
293 	dc->dc_sh = ga->ga_ioh;
294 
295 	dc->dc_boardrev = rex_revision(dc);
296 
297 	wsfont_init();
298 
299 	dc->dc_font = wsfont_find(NULL, 8, 16, 0, WSDISPLAY_FONTORDER_L2R,
300 	    WSDISPLAY_FONTORDER_L2R);
301 
302 	if (dc->dc_font < 0)
303 		panic("light_attach_common: no suitable fonts");
304 
305 	if (wsfont_lock(dc->dc_font, &dc->dc_fontdata))
306 		panic("light_attach_common: unable to lock font data");
307 
308 	rex_vc1_write(dc, rex_vc1_read(dc) & ~(VC1_SYSCTL_CURSOR |
309 	    VC1_SYSCTL_CURSOR_ON));
310 	rex_fill_rect(dc, 0, 0, LIGHT_XRES - 1, LIGHT_YRES - 1, 0);
311 }
312 
313 static void
314 light_attach(struct device *parent, struct device *self, void *aux)
315 {
316 	struct gio_attach_args *ga = aux;
317 	struct light_softc *sc = (void *)self;
318 	struct wsemuldisplaydev_attach_args wa;
319 
320 	if (light_is_console && ga->ga_addr == light_console_dc.dc_addr) {
321 		wa.console = 1;
322 		sc->sc_dc = &light_console_dc;
323 	} else {
324 		wa.console = 0;
325 		sc->sc_dc = malloc(sizeof(struct light_devconfig), M_DEVBUF,
326 		    M_WAITOK | M_ZERO);
327 		if (sc->sc_dc == NULL)
328 			panic("light_attach: out of memory");
329 
330 		light_attach_common(sc->sc_dc, ga);
331 	}
332 
333 	aprint_naive(": Display adapter\n");
334 
335 	aprint_normal(": SGI LG%d (board revision %d)\n",
336 	    LIGHT_IS_LG1(sc->sc_dc->dc_boardrev) ? 1 : 2,
337 	    sc->sc_dc->dc_boardrev);
338 
339 	wa.scrdata = &light_screenlist;
340 	wa.accessops = &light_accessops;
341 	wa.accesscookie = sc->sc_dc;
342 
343 	config_found(&sc->sc_dev, &wa, wsemuldisplaydevprint);
344 }
345 
346 int
347 light_cnattach(struct gio_attach_args *ga)
348 {
349 
350 	if (!light_match(NULL, NULL, ga))
351 		return (ENXIO);
352 
353 	light_attach_common(&light_console_dc, ga);
354 
355 	wsdisplay_cnattach(&light_screen, &light_console_dc, 0, 0,
356 	    LIGHT_ATTR_ENCODE(WSCOL_WHITE, WSCOL_BLACK));
357 
358 	light_is_console = 1;
359 
360 	return (0);
361 }
362 
363 /*******************************************************************************
364  * wsdisplay_emulops
365  ******************************************************************************/
366 
367 static void
368 light_cursor(void *c, int on, int row, int col)
369 {
370 	/* XXX */
371 }
372 
373 static int
374 light_mapchar(void *c, int ch, unsigned int *cp)
375 {
376 	struct light_devconfig *dc = (void *)c;
377 
378 	if (dc->dc_fontdata->encoding != WSDISPLAY_FONTENC_ISO) {
379 		ch = wsfont_map_unichar(dc->dc_fontdata, ch);
380 
381 		if (ch < 0)
382 			goto fail;
383 	}
384 
385 	if (ch < dc->dc_fontdata->firstchar ||
386 	    ch >= dc->dc_fontdata->firstchar + dc->dc_fontdata->numchars)
387 		goto fail;
388 
389 	*cp = ch;
390 	return 5;
391 
392 fail:
393 	*cp = ' ';
394 	return 0;
395 }
396 
397 static void
398 light_putchar(void *c, int row, int col, u_int ch, long attr)
399 {
400         struct light_devconfig *dc = c;
401 	struct wsdisplay_font *font = dc->dc_fontdata;
402 	uint8_t *bitmap;
403 	uint32_t pattern;
404 	int i, x, y;
405 
406 	bitmap = (u_int8_t *)font->data +
407 	    ((ch - font->firstchar) * font->fontheight * font->stride);
408 	x = col * font->fontwidth;
409 	y = row * font->fontheight;
410 
411 	rex_wait(dc);
412 
413 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_YSTARTI, y);
414 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_YENDI, y + font->fontheight - 1);
415 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_XSTARTI, x);
416 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_XENDI, x + font->fontwidth - 1);
417 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_COLORREDI, LIGHT_ATTR_FG(attr));
418 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_COLORBACK, LIGHT_ATTR_BG(attr));
419 	rex_write(dc, REX_PAGE0_GO,  REX_P0REG_COMMAND, REX_OP_NOP);
420 
421 	rex_wait(dc);
422 
423 	rex_write(dc, REX_PAGE0_SET, REX_P0REG_COMMAND, REX_OP_DRAW |
424 	    REX_LOGICOP_SRC | REX_OP_FLG_ENZPATTERN | REX_OP_FLG_QUADMODE |
425 	    REX_OP_FLG_XYCONTINUE | REX_OP_FLG_STOPONX | REX_OP_FLG_BLOCK |
426 	    REX_OP_FLG_LENGTH32 | REX_OP_FLG_ZOPAQUE);
427 
428 	for (i = 0; i < font->fontheight; i++) {
429 		/* XXX assumes font->fontwidth == 8 */
430 		pattern = *bitmap << 24;
431 		rex_write(dc, REX_PAGE0_GO, REX_P0REG_ZPATTERN, pattern);
432 		bitmap += font->stride;
433 	}
434 }
435 
436 /* copy set of columns within the same line */
437 static void
438 light_copycols(void *c, int row, int srccol, int dstcol, int ncols)
439 {
440 	struct light_devconfig *dc = c;
441 	struct wsdisplay_font *font = dc->dc_fontdata;
442 	int from_x, from_y, to_x, to_y, width, height;
443 
444 	from_x	= srccol * font->fontwidth;
445 	from_y	= row * font->fontheight;
446 	to_x	= dstcol * font->fontwidth;
447 	to_y	= from_y;
448 	width	= ncols * font->fontwidth;
449 	height	= font->fontheight;
450 
451 	rex_copy_rect(c, from_x, from_y, to_x, to_y, width, height);
452 }
453 
454 /* erase a set of columns in the same line */
455 static void
456 light_erasecols(void *c, int row, int startcol, int ncols, long attr)
457 {
458 	struct light_devconfig *dc = c;
459 	struct wsdisplay_font *font = dc->dc_fontdata;
460 	int from_x, from_y, to_x, to_y;
461 
462 	from_x	= startcol * font->fontwidth;
463 	from_y	= row * font->fontheight;
464 	to_x	= from_x + (ncols * font->fontwidth) - 1;
465 	to_y	= from_y + font->fontheight - 1;
466 
467 	rex_fill_rect(c, from_x, from_y, to_x, to_y, attr);
468 }
469 
470 /* copy a set of complete rows */
471 static void
472 light_copyrows(void *c, int srcrow, int dstrow, int nrows)
473 {
474 	struct light_devconfig *dc = c;
475 	struct wsdisplay_font *font = dc->dc_fontdata;
476 	int from_x, from_y, to_x, to_y, width, height;
477 
478 	from_x	= 0;
479 	from_y	= srcrow * font->fontheight;
480 	to_x	= 0;
481 	to_y	= dstrow * font->fontheight;
482 	width	= LIGHT_XRES;
483 	height	= nrows * font->fontheight;
484 
485 	rex_copy_rect(c, from_x, from_y, to_x, to_y, width, height);
486 }
487 
488 /* erase a set of complete rows */
489 static void
490 light_eraserows(void *c, int row, int nrows, long attr)
491 {
492 	struct light_devconfig *dc = c;
493 	struct wsdisplay_font *font = dc->dc_fontdata;
494 	int from_x, from_y, to_x, to_y;
495 
496 	from_x	= 0;
497 	from_y	= row * font->fontheight;
498 	to_x	= LIGHT_XRES - 1;
499 	to_y	= from_y + (nrows * font->fontheight) - 1;
500 
501 	rex_fill_rect(c, from_x, from_y, to_x, to_y, attr);
502 }
503 
504 static int
505 light_allocattr(void *c, int fg, int bg, int flags, long *attr)
506 {
507 
508 	if (flags & ~(WSATTR_WSCOLORS | WSATTR_HILIT | WSATTR_REVERSE))
509 		return (EINVAL);
510 
511 	if ((flags & WSATTR_WSCOLORS) == 0) {
512 		fg = WSCOL_WHITE;
513 		bg = WSCOL_BLACK;
514 	}
515 
516 	if (flags & WSATTR_HILIT)
517 		fg += 8;
518 
519 	if (flags & WSATTR_REVERSE) {
520 		int tmp = fg;
521 		fg = bg;
522 		bg = tmp;
523 	}
524 
525 	*attr = LIGHT_ATTR_ENCODE(fg, bg);
526 	return (0);
527 }
528 
529 /*******************************************************************************
530  * wsdisplay_accessops
531  ******************************************************************************/
532 
533 static int
534 light_ioctl(void *c, void *vs, u_long cmd, void *data, int flag,
535     struct lwp *l)
536 {
537 	struct wsdisplay_fbinfo *fbinfo = (struct wsdisplay_fbinfo *)data;
538 
539 	switch (cmd) {
540 	case WSDISPLAYIO_GINFO:
541 		fbinfo->width	= LIGHT_XRES;
542 		fbinfo->height	= LIGHT_YRES;
543 		fbinfo->depth	= LIGHT_DEPTH;
544 		fbinfo->cmsize	= 1 << LIGHT_DEPTH;
545 		return (0);
546 
547 	case WSDISPLAYIO_GMODE:
548 		*(u_int *)data = WSDISPLAYIO_MODE_EMUL;
549 		break;
550 
551 	case WSDISPLAYIO_GTYPE:
552 		*(u_int *)data = WSDISPLAY_TYPE_LIGHT;
553 		return (0);
554 
555 	case WSDISPLAYIO_SVIDEO:
556 		/*
557 		 * Turning off VC1 will stop refreshing the video ram (or so I
558 		 * suspect). We'll blank the screen after bringing it back up,
559 		 * since that's nicer than displaying garbage.
560 		 */
561 		if (*(u_int *)data == WSDISPLAYIO_VIDEO_OFF)
562 			rex_vc1_write(c,rex_vc1_read(c) & ~VC1_SYSCTL_VIDEO_ON);
563 		else {
564 			rex_vc1_write(c, rex_vc1_read(c) | VC1_SYSCTL_VIDEO_ON);
565 			rex_fill_rect(c, 0, 0, LIGHT_XRES-1, LIGHT_YRES-1, 0);
566 		}
567 		return (0);
568 	}
569 
570 	return (EPASSTHROUGH);
571 }
572 
573 static paddr_t
574 light_mmap(void *c, void *vs, off_t off, int prot)
575 {
576         struct light_devconfig *dc = c;
577 
578 	if (off >= 0x7fff)
579 		return (-1);
580 
581 	return (mips_btop(dc->dc_addr + off));
582 }
583 
584 static int
585 light_alloc_screen(void *c, const struct wsscreen_descr *type, void **cookiep,
586     int *curxp, int *curyp, long *attr)
587 {
588 
589 	return (ENOMEM);
590 }
591 
592 static void
593 light_free_screen(void *c, void *cookie)
594 {
595 
596 	panic("light_free_screen");
597 }
598 
599 static int
600 light_show_screen(void *c, void *cookie, int waitok,
601     void (*cb)(void *, int, int), void *cbarg)
602 {
603 
604 	return (0);
605 }
606