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 <drm/drmP.h>
15#include <drm/drm_crtc.h>
16#include <drm/drm_crtc_helper.h>
17#include <drm/drm_plane_helper.h>
18#include "udl_drv.h"
19
20/*
21 * All DisplayLink bulk operations start with 0xAF, followed by specific code
22 * All operations are written to buffers which then later get sent to device
23 */
24static char *udl_set_register(char *buf, u8 reg, u8 val)
25{
26	*buf++ = 0xAF;
27	*buf++ = 0x20;
28	*buf++ = reg;
29	*buf++ = val;
30	return buf;
31}
32
33static char *udl_vidreg_lock(char *buf)
34{
35	return udl_set_register(buf, 0xFF, 0x00);
36}
37
38static char *udl_vidreg_unlock(char *buf)
39{
40	return udl_set_register(buf, 0xFF, 0xFF);
41}
42
43/*
44 * On/Off for driving the DisplayLink framebuffer to the display
45 *  0x00 H and V sync on
46 *  0x01 H and V sync off (screen blank but powered)
47 *  0x07 DPMS powerdown (requires modeset to come back)
48 */
49static char *udl_set_blank(char *buf, int dpms_mode)
50{
51	u8 reg;
52	switch (dpms_mode) {
53	case DRM_MODE_DPMS_OFF:
54		reg = 0x07;
55		break;
56	case DRM_MODE_DPMS_STANDBY:
57		reg = 0x05;
58		break;
59	case DRM_MODE_DPMS_SUSPEND:
60		reg = 0x01;
61		break;
62	case DRM_MODE_DPMS_ON:
63		reg = 0x00;
64		break;
65	}
66
67	return udl_set_register(buf, 0x1f, reg);
68}
69
70static char *udl_set_color_depth(char *buf, u8 selection)
71{
72	return udl_set_register(buf, 0x00, selection);
73}
74
75static char *udl_set_base16bpp(char *wrptr, u32 base)
76{
77	/* the base pointer is 16 bits wide, 0x20 is hi byte. */
78	wrptr = udl_set_register(wrptr, 0x20, base >> 16);
79	wrptr = udl_set_register(wrptr, 0x21, base >> 8);
80	return udl_set_register(wrptr, 0x22, base);
81}
82
83/*
84 * DisplayLink HW has separate 16bpp and 8bpp framebuffers.
85 * In 24bpp modes, the low 323 RGB bits go in the 8bpp framebuffer
86 */
87static char *udl_set_base8bpp(char *wrptr, u32 base)
88{
89	wrptr = udl_set_register(wrptr, 0x26, base >> 16);
90	wrptr = udl_set_register(wrptr, 0x27, base >> 8);
91	return udl_set_register(wrptr, 0x28, base);
92}
93
94static char *udl_set_register_16(char *wrptr, u8 reg, u16 value)
95{
96	wrptr = udl_set_register(wrptr, reg, value >> 8);
97	return udl_set_register(wrptr, reg+1, value);
98}
99
100/*
101 * This is kind of weird because the controller takes some
102 * register values in a different byte order than other registers.
103 */
104static char *udl_set_register_16be(char *wrptr, u8 reg, u16 value)
105{
106	wrptr = udl_set_register(wrptr, reg, value);
107	return udl_set_register(wrptr, reg+1, value >> 8);
108}
109
110/*
111 * LFSR is linear feedback shift register. The reason we have this is
112 * because the display controller needs to minimize the clock depth of
113 * various counters used in the display path. So this code reverses the
114 * provided value into the lfsr16 value by counting backwards to get
115 * the value that needs to be set in the hardware comparator to get the
116 * same actual count. This makes sense once you read above a couple of
117 * times and think about it from a hardware perspective.
118 */
119static u16 udl_lfsr16(u16 actual_count)
120{
121	u32 lv = 0xFFFF; /* This is the lfsr value that the hw starts with */
122
123	while (actual_count--) {
124		lv =	 ((lv << 1) |
125			(((lv >> 15) ^ (lv >> 4) ^ (lv >> 2) ^ (lv >> 1)) & 1))
126			& 0xFFFF;
127	}
128
129	return (u16) lv;
130}
131
132/*
133 * This does LFSR conversion on the value that is to be written.
134 * See LFSR explanation above for more detail.
135 */
136static char *udl_set_register_lfsr16(char *wrptr, u8 reg, u16 value)
137{
138	return udl_set_register_16(wrptr, reg, udl_lfsr16(value));
139}
140
141/*
142 * This takes a standard fbdev screeninfo struct and all of its monitor mode
143 * details and converts them into the DisplayLink equivalent register commands.
144  ERR(vreg(dev,               0x00, (color_depth == 16) ? 0 : 1));
145  ERR(vreg_lfsr16(dev,        0x01, xDisplayStart));
146  ERR(vreg_lfsr16(dev,        0x03, xDisplayEnd));
147  ERR(vreg_lfsr16(dev,        0x05, yDisplayStart));
148  ERR(vreg_lfsr16(dev,        0x07, yDisplayEnd));
149  ERR(vreg_lfsr16(dev,        0x09, xEndCount));
150  ERR(vreg_lfsr16(dev,        0x0B, hSyncStart));
151  ERR(vreg_lfsr16(dev,        0x0D, hSyncEnd));
152  ERR(vreg_big_endian(dev,    0x0F, hPixels));
153  ERR(vreg_lfsr16(dev,        0x11, yEndCount));
154  ERR(vreg_lfsr16(dev,        0x13, vSyncStart));
155  ERR(vreg_lfsr16(dev,        0x15, vSyncEnd));
156  ERR(vreg_big_endian(dev,    0x17, vPixels));
157  ERR(vreg_little_endian(dev, 0x1B, pixelClock5KHz));
158
159  ERR(vreg(dev,               0x1F, 0));
160
161  ERR(vbuf(dev, WRITE_VIDREG_UNLOCK, DSIZEOF(WRITE_VIDREG_UNLOCK)));
162 */
163static char *udl_set_vid_cmds(char *wrptr, struct drm_display_mode *mode)
164{
165	u16 xds, yds;
166	u16 xde, yde;
167	u16 yec;
168
169	/* x display start */
170	xds = mode->crtc_htotal - mode->crtc_hsync_start;
171	wrptr = udl_set_register_lfsr16(wrptr, 0x01, xds);
172	/* x display end */
173	xde = xds + mode->crtc_hdisplay;
174	wrptr = udl_set_register_lfsr16(wrptr, 0x03, xde);
175
176	/* y display start */
177	yds = mode->crtc_vtotal - mode->crtc_vsync_start;
178	wrptr = udl_set_register_lfsr16(wrptr, 0x05, yds);
179	/* y display end */
180	yde = yds + mode->crtc_vdisplay;
181	wrptr = udl_set_register_lfsr16(wrptr, 0x07, yde);
182
183	/* x end count is active + blanking - 1 */
184	wrptr = udl_set_register_lfsr16(wrptr, 0x09,
185					mode->crtc_htotal - 1);
186
187	/* libdlo hardcodes hsync start to 1 */
188	wrptr = udl_set_register_lfsr16(wrptr, 0x0B, 1);
189
190	/* hsync end is width of sync pulse + 1 */
191	wrptr = udl_set_register_lfsr16(wrptr, 0x0D,
192					mode->crtc_hsync_end - mode->crtc_hsync_start + 1);
193
194	/* hpixels is active pixels */
195	wrptr = udl_set_register_16(wrptr, 0x0F, mode->hdisplay);
196
197	/* yendcount is vertical active + vertical blanking */
198	yec = mode->crtc_vtotal;
199	wrptr = udl_set_register_lfsr16(wrptr, 0x11, yec);
200
201	/* libdlo hardcodes vsync start to 0 */
202	wrptr = udl_set_register_lfsr16(wrptr, 0x13, 0);
203
204	/* vsync end is width of vsync pulse */
205	wrptr = udl_set_register_lfsr16(wrptr, 0x15, mode->crtc_vsync_end - mode->crtc_vsync_start);
206
207	/* vpixels is active pixels */
208	wrptr = udl_set_register_16(wrptr, 0x17, mode->crtc_vdisplay);
209
210	wrptr = udl_set_register_16be(wrptr, 0x1B,
211				      mode->clock / 5);
212
213	return wrptr;
214}
215
216static char *udl_dummy_render(char *wrptr)
217{
218	*wrptr++ = 0xAF;
219	*wrptr++ = 0x6A; /* copy */
220	*wrptr++ = 0x00; /* from addr */
221	*wrptr++ = 0x00;
222	*wrptr++ = 0x00;
223	*wrptr++ = 0x01; /* one pixel */
224	*wrptr++ = 0x00; /* to address */
225	*wrptr++ = 0x00;
226	*wrptr++ = 0x00;
227	return wrptr;
228}
229
230static int udl_crtc_write_mode_to_hw(struct drm_crtc *crtc)
231{
232	struct drm_device *dev = crtc->dev;
233	struct udl_device *udl = dev->dev_private;
234	struct urb *urb;
235	char *buf;
236	int retval;
237
238	urb = udl_get_urb(dev);
239	if (!urb)
240		return -ENOMEM;
241
242	buf = (char *)urb->transfer_buffer;
243
244	memcpy(buf, udl->mode_buf, udl->mode_buf_len);
245	retval = udl_submit_urb(dev, urb, udl->mode_buf_len);
246	DRM_INFO("write mode info %d\n", udl->mode_buf_len);
247	return retval;
248}
249
250
251static void udl_crtc_dpms(struct drm_crtc *crtc, int mode)
252{
253	struct drm_device *dev = crtc->dev;
254	struct udl_device *udl = dev->dev_private;
255	int retval;
256
257	if (mode == DRM_MODE_DPMS_OFF) {
258		char *buf;
259		struct urb *urb;
260		urb = udl_get_urb(dev);
261		if (!urb)
262			return;
263
264		buf = (char *)urb->transfer_buffer;
265		buf = udl_vidreg_lock(buf);
266		buf = udl_set_blank(buf, mode);
267		buf = udl_vidreg_unlock(buf);
268
269		buf = udl_dummy_render(buf);
270		retval = udl_submit_urb(dev, urb, buf - (char *)
271					urb->transfer_buffer);
272	} else {
273		if (udl->mode_buf_len == 0) {
274			DRM_ERROR("Trying to enable DPMS with no mode\n");
275			return;
276		}
277		udl_crtc_write_mode_to_hw(crtc);
278	}
279
280}
281
282static bool udl_crtc_mode_fixup(struct drm_crtc *crtc,
283				  const struct drm_display_mode *mode,
284				  struct drm_display_mode *adjusted_mode)
285
286{
287	return true;
288}
289
290#if 0
291static int
292udl_pipe_set_base_atomic(struct drm_crtc *crtc, struct drm_framebuffer *fb,
293			   int x, int y, enum mode_set_atomic state)
294{
295	return 0;
296}
297
298static int
299udl_pipe_set_base(struct drm_crtc *crtc, int x, int y,
300		    struct drm_framebuffer *old_fb)
301{
302	return 0;
303}
304#endif
305
306static int udl_crtc_mode_set(struct drm_crtc *crtc,
307			       struct drm_display_mode *mode,
308			       struct drm_display_mode *adjusted_mode,
309			       int x, int y,
310			       struct drm_framebuffer *old_fb)
311
312{
313	struct drm_device *dev = crtc->dev;
314	struct udl_framebuffer *ufb = to_udl_fb(crtc->primary->fb);
315	struct udl_device *udl = dev->dev_private;
316	char *buf;
317	char *wrptr;
318	int color_depth = 0;
319
320	buf = (char *)udl->mode_buf;
321
322	/* for now we just clip 24 -> 16 - if we fix that fix this */
323	/*if  (crtc->fb->bits_per_pixel != 16)
324	  color_depth = 1; */
325
326	/* This first section has to do with setting the base address on the
327	* controller * associated with the display. There are 2 base
328	* pointers, currently, we only * use the 16 bpp segment.
329	*/
330	wrptr = udl_vidreg_lock(buf);
331	wrptr = udl_set_color_depth(wrptr, color_depth);
332	/* set base for 16bpp segment to 0 */
333	wrptr = udl_set_base16bpp(wrptr, 0);
334	/* set base for 8bpp segment to end of fb */
335	wrptr = udl_set_base8bpp(wrptr, 2 * mode->vdisplay * mode->hdisplay);
336
337	wrptr = udl_set_vid_cmds(wrptr, adjusted_mode);
338	wrptr = udl_set_blank(wrptr, DRM_MODE_DPMS_ON);
339	wrptr = udl_vidreg_unlock(wrptr);
340
341	wrptr = udl_dummy_render(wrptr);
342
343	if (old_fb) {
344		struct udl_framebuffer *uold_fb = to_udl_fb(old_fb);
345		uold_fb->active_16 = false;
346	}
347	ufb->active_16 = true;
348	udl->mode_buf_len = wrptr - buf;
349
350	/* damage all of it */
351	udl_handle_damage(ufb, 0, 0, ufb->base.width, ufb->base.height);
352	return 0;
353}
354
355
356static void udl_crtc_disable(struct drm_crtc *crtc)
357{
358	udl_crtc_dpms(crtc, DRM_MODE_DPMS_OFF);
359}
360
361static void udl_crtc_destroy(struct drm_crtc *crtc)
362{
363	drm_crtc_cleanup(crtc);
364	kfree(crtc);
365}
366
367static int udl_crtc_page_flip(struct drm_crtc *crtc,
368			      struct drm_framebuffer *fb,
369			      struct drm_pending_vblank_event *event,
370			      uint32_t page_flip_flags)
371{
372	struct udl_framebuffer *ufb = to_udl_fb(fb);
373	struct drm_device *dev = crtc->dev;
374	unsigned long flags;
375
376	struct drm_framebuffer *old_fb = crtc->primary->fb;
377	if (old_fb) {
378		struct udl_framebuffer *uold_fb = to_udl_fb(old_fb);
379		uold_fb->active_16 = false;
380	}
381	ufb->active_16 = true;
382
383	udl_handle_damage(ufb, 0, 0, fb->width, fb->height);
384
385	spin_lock_irqsave(&dev->event_lock, flags);
386	if (event)
387		drm_send_vblank_event(dev, 0, event);
388	spin_unlock_irqrestore(&dev->event_lock, flags);
389	crtc->primary->fb = fb;
390
391	return 0;
392}
393
394static void udl_crtc_prepare(struct drm_crtc *crtc)
395{
396}
397
398static void udl_crtc_commit(struct drm_crtc *crtc)
399{
400	udl_crtc_dpms(crtc, DRM_MODE_DPMS_ON);
401}
402
403static struct drm_crtc_helper_funcs udl_helper_funcs = {
404	.dpms = udl_crtc_dpms,
405	.mode_fixup = udl_crtc_mode_fixup,
406	.mode_set = udl_crtc_mode_set,
407	.prepare = udl_crtc_prepare,
408	.commit = udl_crtc_commit,
409	.disable = udl_crtc_disable,
410};
411
412static const struct drm_crtc_funcs udl_crtc_funcs = {
413	.set_config = drm_crtc_helper_set_config,
414	.destroy = udl_crtc_destroy,
415	.page_flip = udl_crtc_page_flip,
416};
417
418static int udl_crtc_init(struct drm_device *dev)
419{
420	struct drm_crtc *crtc;
421
422	crtc = kzalloc(sizeof(struct drm_crtc) + sizeof(struct drm_connector *), GFP_KERNEL);
423	if (crtc == NULL)
424		return -ENOMEM;
425
426	drm_crtc_init(dev, crtc, &udl_crtc_funcs);
427	drm_crtc_helper_add(crtc, &udl_helper_funcs);
428
429	return 0;
430}
431
432static const struct drm_mode_config_funcs udl_mode_funcs = {
433	.fb_create = udl_fb_user_fb_create,
434	.output_poll_changed = NULL,
435};
436
437int udl_modeset_init(struct drm_device *dev)
438{
439	struct drm_encoder *encoder;
440	drm_mode_config_init(dev);
441
442	dev->mode_config.min_width = 640;
443	dev->mode_config.min_height = 480;
444
445	dev->mode_config.max_width = 2048;
446	dev->mode_config.max_height = 2048;
447
448	dev->mode_config.prefer_shadow = 0;
449	dev->mode_config.preferred_depth = 24;
450
451	dev->mode_config.funcs = &udl_mode_funcs;
452
453	drm_mode_create_dirty_info_property(dev);
454
455	udl_crtc_init(dev);
456
457	encoder = udl_encoder_init(dev);
458
459	udl_connector_init(dev, encoder);
460
461	return 0;
462}
463
464void udl_modeset_cleanup(struct drm_device *dev)
465{
466	drm_mode_config_cleanup(dev);
467}
468