xref: /openbmc/linux/drivers/gpu/drm/udl/udl_modeset.c (revision 95e9fd10)
1 /*
2  * Copyright (C) 2012 Red Hat
3  *
4  * based in parts on udlfb.c:
5  * Copyright (C) 2009 Roberto De Ioris <roberto@unbit.it>
6  * Copyright (C) 2009 Jaya Kumar <jayakumar.lkml@gmail.com>
7  * Copyright (C) 2009 Bernie Thompson <bernie@plugable.com>
8 
9  * This file is subject to the terms and conditions of the GNU General Public
10  * License v2. See the file COPYING in the main directory of this archive for
11  * more details.
12  */
13 
14 #include "drmP.h"
15 #include "drm_crtc.h"
16 #include "drm_crtc_helper.h"
17 #include "udl_drv.h"
18 
19 /*
20  * All DisplayLink bulk operations start with 0xAF, followed by specific code
21  * All operations are written to buffers which then later get sent to device
22  */
23 static char *udl_set_register(char *buf, u8 reg, u8 val)
24 {
25 	*buf++ = 0xAF;
26 	*buf++ = 0x20;
27 	*buf++ = reg;
28 	*buf++ = val;
29 	return buf;
30 }
31 
32 static char *udl_vidreg_lock(char *buf)
33 {
34 	return udl_set_register(buf, 0xFF, 0x00);
35 }
36 
37 static char *udl_vidreg_unlock(char *buf)
38 {
39 	return udl_set_register(buf, 0xFF, 0xFF);
40 }
41 
42 /*
43  * On/Off for driving the DisplayLink framebuffer to the display
44  *  0x00 H and V sync on
45  *  0x01 H and V sync off (screen blank but powered)
46  *  0x07 DPMS powerdown (requires modeset to come back)
47  */
48 static char *udl_set_blank(char *buf, int dpms_mode)
49 {
50 	u8 reg;
51 	switch (dpms_mode) {
52 	case DRM_MODE_DPMS_OFF:
53 		reg = 0x07;
54 		break;
55 	case DRM_MODE_DPMS_STANDBY:
56 		reg = 0x05;
57 		break;
58 	case DRM_MODE_DPMS_SUSPEND:
59 		reg = 0x01;
60 		break;
61 	case DRM_MODE_DPMS_ON:
62 		reg = 0x00;
63 		break;
64 	}
65 
66 	return udl_set_register(buf, 0x1f, reg);
67 }
68 
69 static char *udl_set_color_depth(char *buf, u8 selection)
70 {
71 	return udl_set_register(buf, 0x00, selection);
72 }
73 
74 static char *udl_set_base16bpp(char *wrptr, u32 base)
75 {
76 	/* the base pointer is 16 bits wide, 0x20 is hi byte. */
77 	wrptr = udl_set_register(wrptr, 0x20, base >> 16);
78 	wrptr = udl_set_register(wrptr, 0x21, base >> 8);
79 	return udl_set_register(wrptr, 0x22, base);
80 }
81 
82 /*
83  * DisplayLink HW has separate 16bpp and 8bpp framebuffers.
84  * In 24bpp modes, the low 323 RGB bits go in the 8bpp framebuffer
85  */
86 static char *udl_set_base8bpp(char *wrptr, u32 base)
87 {
88 	wrptr = udl_set_register(wrptr, 0x26, base >> 16);
89 	wrptr = udl_set_register(wrptr, 0x27, base >> 8);
90 	return udl_set_register(wrptr, 0x28, base);
91 }
92 
93 static char *udl_set_register_16(char *wrptr, u8 reg, u16 value)
94 {
95 	wrptr = udl_set_register(wrptr, reg, value >> 8);
96 	return udl_set_register(wrptr, reg+1, value);
97 }
98 
99 /*
100  * This is kind of weird because the controller takes some
101  * register values in a different byte order than other registers.
102  */
103 static char *udl_set_register_16be(char *wrptr, u8 reg, u16 value)
104 {
105 	wrptr = udl_set_register(wrptr, reg, value);
106 	return udl_set_register(wrptr, reg+1, value >> 8);
107 }
108 
109 /*
110  * LFSR is linear feedback shift register. The reason we have this is
111  * because the display controller needs to minimize the clock depth of
112  * various counters used in the display path. So this code reverses the
113  * provided value into the lfsr16 value by counting backwards to get
114  * the value that needs to be set in the hardware comparator to get the
115  * same actual count. This makes sense once you read above a couple of
116  * times and think about it from a hardware perspective.
117  */
118 static u16 udl_lfsr16(u16 actual_count)
119 {
120 	u32 lv = 0xFFFF; /* This is the lfsr value that the hw starts with */
121 
122 	while (actual_count--) {
123 		lv =	 ((lv << 1) |
124 			(((lv >> 15) ^ (lv >> 4) ^ (lv >> 2) ^ (lv >> 1)) & 1))
125 			& 0xFFFF;
126 	}
127 
128 	return (u16) lv;
129 }
130 
131 /*
132  * This does LFSR conversion on the value that is to be written.
133  * See LFSR explanation above for more detail.
134  */
135 static char *udl_set_register_lfsr16(char *wrptr, u8 reg, u16 value)
136 {
137 	return udl_set_register_16(wrptr, reg, udl_lfsr16(value));
138 }
139 
140 /*
141  * This takes a standard fbdev screeninfo struct and all of its monitor mode
142  * details and converts them into the DisplayLink equivalent register commands.
143   ERR(vreg(dev,               0x00, (color_depth == 16) ? 0 : 1));
144   ERR(vreg_lfsr16(dev,        0x01, xDisplayStart));
145   ERR(vreg_lfsr16(dev,        0x03, xDisplayEnd));
146   ERR(vreg_lfsr16(dev,        0x05, yDisplayStart));
147   ERR(vreg_lfsr16(dev,        0x07, yDisplayEnd));
148   ERR(vreg_lfsr16(dev,        0x09, xEndCount));
149   ERR(vreg_lfsr16(dev,        0x0B, hSyncStart));
150   ERR(vreg_lfsr16(dev,        0x0D, hSyncEnd));
151   ERR(vreg_big_endian(dev,    0x0F, hPixels));
152   ERR(vreg_lfsr16(dev,        0x11, yEndCount));
153   ERR(vreg_lfsr16(dev,        0x13, vSyncStart));
154   ERR(vreg_lfsr16(dev,        0x15, vSyncEnd));
155   ERR(vreg_big_endian(dev,    0x17, vPixels));
156   ERR(vreg_little_endian(dev, 0x1B, pixelClock5KHz));
157 
158   ERR(vreg(dev,               0x1F, 0));
159 
160   ERR(vbuf(dev, WRITE_VIDREG_UNLOCK, DSIZEOF(WRITE_VIDREG_UNLOCK)));
161  */
162 static char *udl_set_vid_cmds(char *wrptr, struct drm_display_mode *mode)
163 {
164 	u16 xds, yds;
165 	u16 xde, yde;
166 	u16 yec;
167 
168 	/* x display start */
169 	xds = mode->crtc_htotal - mode->crtc_hsync_start;
170 	wrptr = udl_set_register_lfsr16(wrptr, 0x01, xds);
171 	/* x display end */
172 	xde = xds + mode->crtc_hdisplay;
173 	wrptr = udl_set_register_lfsr16(wrptr, 0x03, xde);
174 
175 	/* y display start */
176 	yds = mode->crtc_vtotal - mode->crtc_vsync_start;
177 	wrptr = udl_set_register_lfsr16(wrptr, 0x05, yds);
178 	/* y display end */
179 	yde = yds + mode->crtc_vdisplay;
180 	wrptr = udl_set_register_lfsr16(wrptr, 0x07, yde);
181 
182 	/* x end count is active + blanking - 1 */
183 	wrptr = udl_set_register_lfsr16(wrptr, 0x09,
184 					mode->crtc_htotal - 1);
185 
186 	/* libdlo hardcodes hsync start to 1 */
187 	wrptr = udl_set_register_lfsr16(wrptr, 0x0B, 1);
188 
189 	/* hsync end is width of sync pulse + 1 */
190 	wrptr = udl_set_register_lfsr16(wrptr, 0x0D,
191 					mode->crtc_hsync_end - mode->crtc_hsync_start + 1);
192 
193 	/* hpixels is active pixels */
194 	wrptr = udl_set_register_16(wrptr, 0x0F, mode->hdisplay);
195 
196 	/* yendcount is vertical active + vertical blanking */
197 	yec = mode->crtc_vtotal;
198 	wrptr = udl_set_register_lfsr16(wrptr, 0x11, yec);
199 
200 	/* libdlo hardcodes vsync start to 0 */
201 	wrptr = udl_set_register_lfsr16(wrptr, 0x13, 0);
202 
203 	/* vsync end is width of vsync pulse */
204 	wrptr = udl_set_register_lfsr16(wrptr, 0x15, mode->crtc_vsync_end - mode->crtc_vsync_start);
205 
206 	/* vpixels is active pixels */
207 	wrptr = udl_set_register_16(wrptr, 0x17, mode->crtc_vdisplay);
208 
209 	wrptr = udl_set_register_16be(wrptr, 0x1B,
210 				      mode->clock / 5);
211 
212 	return wrptr;
213 }
214 
215 static char *udl_dummy_render(char *wrptr)
216 {
217 	*wrptr++ = 0xAF;
218 	*wrptr++ = 0x6A; /* copy */
219 	*wrptr++ = 0x00; /* from addr */
220 	*wrptr++ = 0x00;
221 	*wrptr++ = 0x00;
222 	*wrptr++ = 0x01; /* one pixel */
223 	*wrptr++ = 0x00; /* to address */
224 	*wrptr++ = 0x00;
225 	*wrptr++ = 0x00;
226 	return wrptr;
227 }
228 
229 static int udl_crtc_write_mode_to_hw(struct drm_crtc *crtc)
230 {
231 	struct drm_device *dev = crtc->dev;
232 	struct udl_device *udl = dev->dev_private;
233 	struct urb *urb;
234 	char *buf;
235 	int retval;
236 
237 	urb = udl_get_urb(dev);
238 	if (!urb)
239 		return -ENOMEM;
240 
241 	buf = (char *)urb->transfer_buffer;
242 
243 	memcpy(buf, udl->mode_buf, udl->mode_buf_len);
244 	retval = udl_submit_urb(dev, urb, udl->mode_buf_len);
245 	DRM_INFO("write mode info %d\n", udl->mode_buf_len);
246 	return retval;
247 }
248 
249 
250 static void udl_crtc_dpms(struct drm_crtc *crtc, int mode)
251 {
252 	struct drm_device *dev = crtc->dev;
253 	struct udl_device *udl = dev->dev_private;
254 	int retval;
255 
256 	if (mode == DRM_MODE_DPMS_OFF) {
257 		char *buf;
258 		struct urb *urb;
259 		urb = udl_get_urb(dev);
260 		if (!urb)
261 			return;
262 
263 		buf = (char *)urb->transfer_buffer;
264 		buf = udl_vidreg_lock(buf);
265 		buf = udl_set_blank(buf, mode);
266 		buf = udl_vidreg_unlock(buf);
267 
268 		buf = udl_dummy_render(buf);
269 		retval = udl_submit_urb(dev, urb, buf - (char *)
270 					urb->transfer_buffer);
271 	} else {
272 		if (udl->mode_buf_len == 0) {
273 			DRM_ERROR("Trying to enable DPMS with no mode\n");
274 			return;
275 		}
276 		udl_crtc_write_mode_to_hw(crtc);
277 	}
278 
279 }
280 
281 static bool udl_crtc_mode_fixup(struct drm_crtc *crtc,
282 				  const struct drm_display_mode *mode,
283 				  struct drm_display_mode *adjusted_mode)
284 
285 {
286 	return true;
287 }
288 
289 #if 0
290 static int
291 udl_pipe_set_base_atomic(struct drm_crtc *crtc, struct drm_framebuffer *fb,
292 			   int x, int y, enum mode_set_atomic state)
293 {
294 	return 0;
295 }
296 
297 static int
298 udl_pipe_set_base(struct drm_crtc *crtc, int x, int y,
299 		    struct drm_framebuffer *old_fb)
300 {
301 	return 0;
302 }
303 #endif
304 
305 static int udl_crtc_mode_set(struct drm_crtc *crtc,
306 			       struct drm_display_mode *mode,
307 			       struct drm_display_mode *adjusted_mode,
308 			       int x, int y,
309 			       struct drm_framebuffer *old_fb)
310 
311 {
312 	struct drm_device *dev = crtc->dev;
313 	struct udl_framebuffer *ufb = to_udl_fb(crtc->fb);
314 	struct udl_device *udl = dev->dev_private;
315 	char *buf;
316 	char *wrptr;
317 	int color_depth = 0;
318 
319 	buf = (char *)udl->mode_buf;
320 
321 	/* for now we just clip 24 -> 16 - if we fix that fix this */
322 	/*if  (crtc->fb->bits_per_pixel != 16)
323 	  color_depth = 1; */
324 
325 	/* This first section has to do with setting the base address on the
326 	* controller * associated with the display. There are 2 base
327 	* pointers, currently, we only * use the 16 bpp segment.
328 	*/
329 	wrptr = udl_vidreg_lock(buf);
330 	wrptr = udl_set_color_depth(wrptr, color_depth);
331 	/* set base for 16bpp segment to 0 */
332 	wrptr = udl_set_base16bpp(wrptr, 0);
333 	/* set base for 8bpp segment to end of fb */
334 	wrptr = udl_set_base8bpp(wrptr, 2 * mode->vdisplay * mode->hdisplay);
335 
336 	wrptr = udl_set_vid_cmds(wrptr, adjusted_mode);
337 	wrptr = udl_set_blank(wrptr, DRM_MODE_DPMS_ON);
338 	wrptr = udl_vidreg_unlock(wrptr);
339 
340 	wrptr = udl_dummy_render(wrptr);
341 
342 	ufb->active_16 = true;
343 	if (old_fb) {
344 		struct udl_framebuffer *uold_fb = to_udl_fb(old_fb);
345 		uold_fb->active_16 = false;
346 	}
347 	udl->mode_buf_len = wrptr - buf;
348 
349 	/* damage all of it */
350 	udl_handle_damage(ufb, 0, 0, ufb->base.width, ufb->base.height);
351 	return 0;
352 }
353 
354 
355 static void udl_crtc_disable(struct drm_crtc *crtc)
356 {
357 	udl_crtc_dpms(crtc, DRM_MODE_DPMS_OFF);
358 }
359 
360 static void udl_crtc_destroy(struct drm_crtc *crtc)
361 {
362 	drm_crtc_cleanup(crtc);
363 	kfree(crtc);
364 }
365 
366 static void udl_load_lut(struct drm_crtc *crtc)
367 {
368 }
369 
370 static void udl_crtc_prepare(struct drm_crtc *crtc)
371 {
372 }
373 
374 static void udl_crtc_commit(struct drm_crtc *crtc)
375 {
376 	udl_crtc_dpms(crtc, DRM_MODE_DPMS_ON);
377 }
378 
379 static struct drm_crtc_helper_funcs udl_helper_funcs = {
380 	.dpms = udl_crtc_dpms,
381 	.mode_fixup = udl_crtc_mode_fixup,
382 	.mode_set = udl_crtc_mode_set,
383 	.prepare = udl_crtc_prepare,
384 	.commit = udl_crtc_commit,
385 	.disable = udl_crtc_disable,
386 	.load_lut = udl_load_lut,
387 };
388 
389 static const struct drm_crtc_funcs udl_crtc_funcs = {
390 	.set_config = drm_crtc_helper_set_config,
391 	.destroy = udl_crtc_destroy,
392 };
393 
394 int udl_crtc_init(struct drm_device *dev)
395 {
396 	struct drm_crtc *crtc;
397 
398 	crtc = kzalloc(sizeof(struct drm_crtc) + sizeof(struct drm_connector *), GFP_KERNEL);
399 	if (crtc == NULL)
400 		return -ENOMEM;
401 
402 	drm_crtc_init(dev, crtc, &udl_crtc_funcs);
403 	drm_crtc_helper_add(crtc, &udl_helper_funcs);
404 
405 	return 0;
406 }
407 
408 static const struct drm_mode_config_funcs udl_mode_funcs = {
409 	.fb_create = udl_fb_user_fb_create,
410 	.output_poll_changed = NULL,
411 };
412 
413 int udl_modeset_init(struct drm_device *dev)
414 {
415 	struct drm_encoder *encoder;
416 	drm_mode_config_init(dev);
417 
418 	dev->mode_config.min_width = 640;
419 	dev->mode_config.min_height = 480;
420 
421 	dev->mode_config.max_width = 2048;
422 	dev->mode_config.max_height = 2048;
423 
424 	dev->mode_config.prefer_shadow = 0;
425 	dev->mode_config.preferred_depth = 24;
426 
427 	dev->mode_config.funcs = &udl_mode_funcs;
428 
429 	drm_mode_create_dirty_info_property(dev);
430 
431 	udl_crtc_init(dev);
432 
433 	encoder = udl_encoder_init(dev);
434 
435 	udl_connector_init(dev, encoder);
436 
437 	return 0;
438 }
439 
440 void udl_modeset_cleanup(struct drm_device *dev)
441 {
442 	drm_mode_config_cleanup(dev);
443 }
444