xref: /openbmc/linux/drivers/video/fbdev/hyperv_fb.c (revision 275876e2)
1 /*
2  * Copyright (c) 2012, Microsoft Corporation.
3  *
4  * Author:
5  *   Haiyang Zhang <haiyangz@microsoft.com>
6  *
7  * This program is free software; you can redistribute it and/or modify it
8  * under the terms of the GNU General Public License version 2 as published
9  * by the Free Software Foundation.
10  *
11  * This program is distributed in the hope that it will be useful, but
12  * WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
14  * NON INFRINGEMENT.  See the GNU General Public License for more
15  * details.
16  */
17 
18 /*
19  * Hyper-V Synthetic Video Frame Buffer Driver
20  *
21  * This is the driver for the Hyper-V Synthetic Video, which supports
22  * screen resolution up to Full HD 1920x1080 with 32 bit color on Windows
23  * Server 2012, and 1600x1200 with 16 bit color on Windows Server 2008 R2
24  * or earlier.
25  *
26  * It also solves the double mouse cursor issue of the emulated video mode.
27  *
28  * The default screen resolution is 1152x864, which may be changed by a
29  * kernel parameter:
30  *     video=hyperv_fb:<width>x<height>
31  *     For example: video=hyperv_fb:1280x1024
32  *
33  * Portrait orientation is also supported:
34  *     For example: video=hyperv_fb:864x1152
35  */
36 
37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
38 
39 #include <linux/module.h>
40 #include <linux/kernel.h>
41 #include <linux/init.h>
42 #include <linux/completion.h>
43 #include <linux/fb.h>
44 #include <linux/pci.h>
45 #include <linux/efi.h>
46 
47 #include <linux/hyperv.h>
48 
49 
50 /* Hyper-V Synthetic Video Protocol definitions and structures */
51 #define MAX_VMBUS_PKT_SIZE 0x4000
52 
53 #define SYNTHVID_VERSION(major, minor) ((minor) << 16 | (major))
54 #define SYNTHVID_VERSION_WIN7 SYNTHVID_VERSION(3, 0)
55 #define SYNTHVID_VERSION_WIN8 SYNTHVID_VERSION(3, 2)
56 
57 #define SYNTHVID_DEPTH_WIN7 16
58 #define SYNTHVID_DEPTH_WIN8 32
59 
60 #define SYNTHVID_FB_SIZE_WIN7 (4 * 1024 * 1024)
61 #define SYNTHVID_WIDTH_MAX_WIN7 1600
62 #define SYNTHVID_HEIGHT_MAX_WIN7 1200
63 
64 #define SYNTHVID_FB_SIZE_WIN8 (8 * 1024 * 1024)
65 
66 #define PCI_VENDOR_ID_MICROSOFT 0x1414
67 #define PCI_DEVICE_ID_HYPERV_VIDEO 0x5353
68 
69 
70 enum pipe_msg_type {
71 	PIPE_MSG_INVALID,
72 	PIPE_MSG_DATA,
73 	PIPE_MSG_MAX
74 };
75 
76 struct pipe_msg_hdr {
77 	u32 type;
78 	u32 size; /* size of message after this field */
79 } __packed;
80 
81 
82 enum synthvid_msg_type {
83 	SYNTHVID_ERROR			= 0,
84 	SYNTHVID_VERSION_REQUEST	= 1,
85 	SYNTHVID_VERSION_RESPONSE	= 2,
86 	SYNTHVID_VRAM_LOCATION		= 3,
87 	SYNTHVID_VRAM_LOCATION_ACK	= 4,
88 	SYNTHVID_SITUATION_UPDATE	= 5,
89 	SYNTHVID_SITUATION_UPDATE_ACK	= 6,
90 	SYNTHVID_POINTER_POSITION	= 7,
91 	SYNTHVID_POINTER_SHAPE		= 8,
92 	SYNTHVID_FEATURE_CHANGE		= 9,
93 	SYNTHVID_DIRT			= 10,
94 
95 	SYNTHVID_MAX			= 11
96 };
97 
98 struct synthvid_msg_hdr {
99 	u32 type;
100 	u32 size;  /* size of this header + payload after this field*/
101 } __packed;
102 
103 
104 struct synthvid_version_req {
105 	u32 version;
106 } __packed;
107 
108 struct synthvid_version_resp {
109 	u32 version;
110 	u8 is_accepted;
111 	u8 max_video_outputs;
112 } __packed;
113 
114 struct synthvid_vram_location {
115 	u64 user_ctx;
116 	u8 is_vram_gpa_specified;
117 	u64 vram_gpa;
118 } __packed;
119 
120 struct synthvid_vram_location_ack {
121 	u64 user_ctx;
122 } __packed;
123 
124 struct video_output_situation {
125 	u8 active;
126 	u32 vram_offset;
127 	u8 depth_bits;
128 	u32 width_pixels;
129 	u32 height_pixels;
130 	u32 pitch_bytes;
131 } __packed;
132 
133 struct synthvid_situation_update {
134 	u64 user_ctx;
135 	u8 video_output_count;
136 	struct video_output_situation video_output[1];
137 } __packed;
138 
139 struct synthvid_situation_update_ack {
140 	u64 user_ctx;
141 } __packed;
142 
143 struct synthvid_pointer_position {
144 	u8 is_visible;
145 	u8 video_output;
146 	s32 image_x;
147 	s32 image_y;
148 } __packed;
149 
150 
151 #define CURSOR_MAX_X 96
152 #define CURSOR_MAX_Y 96
153 #define CURSOR_ARGB_PIXEL_SIZE 4
154 #define CURSOR_MAX_SIZE (CURSOR_MAX_X * CURSOR_MAX_Y * CURSOR_ARGB_PIXEL_SIZE)
155 #define CURSOR_COMPLETE (-1)
156 
157 struct synthvid_pointer_shape {
158 	u8 part_idx;
159 	u8 is_argb;
160 	u32 width; /* CURSOR_MAX_X at most */
161 	u32 height; /* CURSOR_MAX_Y at most */
162 	u32 hot_x; /* hotspot relative to upper-left of pointer image */
163 	u32 hot_y;
164 	u8 data[4];
165 } __packed;
166 
167 struct synthvid_feature_change {
168 	u8 is_dirt_needed;
169 	u8 is_ptr_pos_needed;
170 	u8 is_ptr_shape_needed;
171 	u8 is_situ_needed;
172 } __packed;
173 
174 struct rect {
175 	s32 x1, y1; /* top left corner */
176 	s32 x2, y2; /* bottom right corner, exclusive */
177 } __packed;
178 
179 struct synthvid_dirt {
180 	u8 video_output;
181 	u8 dirt_count;
182 	struct rect rect[1];
183 } __packed;
184 
185 struct synthvid_msg {
186 	struct pipe_msg_hdr pipe_hdr;
187 	struct synthvid_msg_hdr vid_hdr;
188 	union {
189 		struct synthvid_version_req ver_req;
190 		struct synthvid_version_resp ver_resp;
191 		struct synthvid_vram_location vram;
192 		struct synthvid_vram_location_ack vram_ack;
193 		struct synthvid_situation_update situ;
194 		struct synthvid_situation_update_ack situ_ack;
195 		struct synthvid_pointer_position ptr_pos;
196 		struct synthvid_pointer_shape ptr_shape;
197 		struct synthvid_feature_change feature_chg;
198 		struct synthvid_dirt dirt;
199 	};
200 } __packed;
201 
202 
203 
204 /* FB driver definitions and structures */
205 #define HVFB_WIDTH 1152 /* default screen width */
206 #define HVFB_HEIGHT 864 /* default screen height */
207 #define HVFB_WIDTH_MIN 640
208 #define HVFB_HEIGHT_MIN 480
209 
210 #define RING_BUFSIZE (256 * 1024)
211 #define VSP_TIMEOUT (10 * HZ)
212 #define HVFB_UPDATE_DELAY (HZ / 20)
213 
214 struct hvfb_par {
215 	struct fb_info *info;
216 	struct resource mem;
217 	bool fb_ready; /* fb device is ready */
218 	struct completion wait;
219 	u32 synthvid_version;
220 
221 	struct delayed_work dwork;
222 	bool update;
223 
224 	u32 pseudo_palette[16];
225 	u8 init_buf[MAX_VMBUS_PKT_SIZE];
226 	u8 recv_buf[MAX_VMBUS_PKT_SIZE];
227 
228 	/* If true, the VSC notifies the VSP on every framebuffer change */
229 	bool synchronous_fb;
230 
231 	struct notifier_block hvfb_panic_nb;
232 };
233 
234 static uint screen_width = HVFB_WIDTH;
235 static uint screen_height = HVFB_HEIGHT;
236 static uint screen_depth;
237 static uint screen_fb_size;
238 
239 /* Send message to Hyper-V host */
240 static inline int synthvid_send(struct hv_device *hdev,
241 				struct synthvid_msg *msg)
242 {
243 	static atomic64_t request_id = ATOMIC64_INIT(0);
244 	int ret;
245 
246 	msg->pipe_hdr.type = PIPE_MSG_DATA;
247 	msg->pipe_hdr.size = msg->vid_hdr.size;
248 
249 	ret = vmbus_sendpacket(hdev->channel, msg,
250 			       msg->vid_hdr.size + sizeof(struct pipe_msg_hdr),
251 			       atomic64_inc_return(&request_id),
252 			       VM_PKT_DATA_INBAND, 0);
253 
254 	if (ret)
255 		pr_err("Unable to send packet via vmbus\n");
256 
257 	return ret;
258 }
259 
260 
261 /* Send screen resolution info to host */
262 static int synthvid_send_situ(struct hv_device *hdev)
263 {
264 	struct fb_info *info = hv_get_drvdata(hdev);
265 	struct synthvid_msg msg;
266 
267 	if (!info)
268 		return -ENODEV;
269 
270 	memset(&msg, 0, sizeof(struct synthvid_msg));
271 
272 	msg.vid_hdr.type = SYNTHVID_SITUATION_UPDATE;
273 	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
274 		sizeof(struct synthvid_situation_update);
275 	msg.situ.user_ctx = 0;
276 	msg.situ.video_output_count = 1;
277 	msg.situ.video_output[0].active = 1;
278 	msg.situ.video_output[0].vram_offset = 0;
279 	msg.situ.video_output[0].depth_bits = info->var.bits_per_pixel;
280 	msg.situ.video_output[0].width_pixels = info->var.xres;
281 	msg.situ.video_output[0].height_pixels = info->var.yres;
282 	msg.situ.video_output[0].pitch_bytes = info->fix.line_length;
283 
284 	synthvid_send(hdev, &msg);
285 
286 	return 0;
287 }
288 
289 /* Send mouse pointer info to host */
290 static int synthvid_send_ptr(struct hv_device *hdev)
291 {
292 	struct synthvid_msg msg;
293 
294 	memset(&msg, 0, sizeof(struct synthvid_msg));
295 	msg.vid_hdr.type = SYNTHVID_POINTER_POSITION;
296 	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
297 		sizeof(struct synthvid_pointer_position);
298 	msg.ptr_pos.is_visible = 1;
299 	msg.ptr_pos.video_output = 0;
300 	msg.ptr_pos.image_x = 0;
301 	msg.ptr_pos.image_y = 0;
302 	synthvid_send(hdev, &msg);
303 
304 	memset(&msg, 0, sizeof(struct synthvid_msg));
305 	msg.vid_hdr.type = SYNTHVID_POINTER_SHAPE;
306 	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
307 		sizeof(struct synthvid_pointer_shape);
308 	msg.ptr_shape.part_idx = CURSOR_COMPLETE;
309 	msg.ptr_shape.is_argb = 1;
310 	msg.ptr_shape.width = 1;
311 	msg.ptr_shape.height = 1;
312 	msg.ptr_shape.hot_x = 0;
313 	msg.ptr_shape.hot_y = 0;
314 	msg.ptr_shape.data[0] = 0;
315 	msg.ptr_shape.data[1] = 1;
316 	msg.ptr_shape.data[2] = 1;
317 	msg.ptr_shape.data[3] = 1;
318 	synthvid_send(hdev, &msg);
319 
320 	return 0;
321 }
322 
323 /* Send updated screen area (dirty rectangle) location to host */
324 static int synthvid_update(struct fb_info *info)
325 {
326 	struct hv_device *hdev = device_to_hv_device(info->device);
327 	struct synthvid_msg msg;
328 
329 	memset(&msg, 0, sizeof(struct synthvid_msg));
330 
331 	msg.vid_hdr.type = SYNTHVID_DIRT;
332 	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
333 		sizeof(struct synthvid_dirt);
334 	msg.dirt.video_output = 0;
335 	msg.dirt.dirt_count = 1;
336 	msg.dirt.rect[0].x1 = 0;
337 	msg.dirt.rect[0].y1 = 0;
338 	msg.dirt.rect[0].x2 = info->var.xres;
339 	msg.dirt.rect[0].y2 = info->var.yres;
340 
341 	synthvid_send(hdev, &msg);
342 
343 	return 0;
344 }
345 
346 
347 /*
348  * Actions on received messages from host:
349  * Complete the wait event.
350  * Or, reply with screen and cursor info.
351  */
352 static void synthvid_recv_sub(struct hv_device *hdev)
353 {
354 	struct fb_info *info = hv_get_drvdata(hdev);
355 	struct hvfb_par *par;
356 	struct synthvid_msg *msg;
357 
358 	if (!info)
359 		return;
360 
361 	par = info->par;
362 	msg = (struct synthvid_msg *)par->recv_buf;
363 
364 	/* Complete the wait event */
365 	if (msg->vid_hdr.type == SYNTHVID_VERSION_RESPONSE ||
366 	    msg->vid_hdr.type == SYNTHVID_VRAM_LOCATION_ACK) {
367 		memcpy(par->init_buf, msg, MAX_VMBUS_PKT_SIZE);
368 		complete(&par->wait);
369 		return;
370 	}
371 
372 	/* Reply with screen and cursor info */
373 	if (msg->vid_hdr.type == SYNTHVID_FEATURE_CHANGE) {
374 		if (par->fb_ready) {
375 			synthvid_send_ptr(hdev);
376 			synthvid_send_situ(hdev);
377 		}
378 
379 		par->update = msg->feature_chg.is_dirt_needed;
380 		if (par->update)
381 			schedule_delayed_work(&par->dwork, HVFB_UPDATE_DELAY);
382 	}
383 }
384 
385 /* Receive callback for messages from the host */
386 static void synthvid_receive(void *ctx)
387 {
388 	struct hv_device *hdev = ctx;
389 	struct fb_info *info = hv_get_drvdata(hdev);
390 	struct hvfb_par *par;
391 	struct synthvid_msg *recv_buf;
392 	u32 bytes_recvd;
393 	u64 req_id;
394 	int ret;
395 
396 	if (!info)
397 		return;
398 
399 	par = info->par;
400 	recv_buf = (struct synthvid_msg *)par->recv_buf;
401 
402 	do {
403 		ret = vmbus_recvpacket(hdev->channel, recv_buf,
404 				       MAX_VMBUS_PKT_SIZE,
405 				       &bytes_recvd, &req_id);
406 		if (bytes_recvd > 0 &&
407 		    recv_buf->pipe_hdr.type == PIPE_MSG_DATA)
408 			synthvid_recv_sub(hdev);
409 	} while (bytes_recvd > 0 && ret == 0);
410 }
411 
412 /* Check synthetic video protocol version with the host */
413 static int synthvid_negotiate_ver(struct hv_device *hdev, u32 ver)
414 {
415 	struct fb_info *info = hv_get_drvdata(hdev);
416 	struct hvfb_par *par = info->par;
417 	struct synthvid_msg *msg = (struct synthvid_msg *)par->init_buf;
418 	int t, ret = 0;
419 
420 	memset(msg, 0, sizeof(struct synthvid_msg));
421 	msg->vid_hdr.type = SYNTHVID_VERSION_REQUEST;
422 	msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
423 		sizeof(struct synthvid_version_req);
424 	msg->ver_req.version = ver;
425 	synthvid_send(hdev, msg);
426 
427 	t = wait_for_completion_timeout(&par->wait, VSP_TIMEOUT);
428 	if (!t) {
429 		pr_err("Time out on waiting version response\n");
430 		ret = -ETIMEDOUT;
431 		goto out;
432 	}
433 	if (!msg->ver_resp.is_accepted) {
434 		ret = -ENODEV;
435 		goto out;
436 	}
437 
438 	par->synthvid_version = ver;
439 
440 out:
441 	return ret;
442 }
443 
444 /* Connect to VSP (Virtual Service Provider) on host */
445 static int synthvid_connect_vsp(struct hv_device *hdev)
446 {
447 	struct fb_info *info = hv_get_drvdata(hdev);
448 	struct hvfb_par *par = info->par;
449 	int ret;
450 
451 	ret = vmbus_open(hdev->channel, RING_BUFSIZE, RING_BUFSIZE,
452 			 NULL, 0, synthvid_receive, hdev);
453 	if (ret) {
454 		pr_err("Unable to open vmbus channel\n");
455 		return ret;
456 	}
457 
458 	/* Negotiate the protocol version with host */
459 	if (vmbus_proto_version == VERSION_WS2008 ||
460 	    vmbus_proto_version == VERSION_WIN7)
461 		ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN7);
462 	else
463 		ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN8);
464 
465 	if (ret) {
466 		pr_err("Synthetic video device version not accepted\n");
467 		goto error;
468 	}
469 
470 	if (par->synthvid_version == SYNTHVID_VERSION_WIN7)
471 		screen_depth = SYNTHVID_DEPTH_WIN7;
472 	else
473 		screen_depth = SYNTHVID_DEPTH_WIN8;
474 
475 	screen_fb_size = hdev->channel->offermsg.offer.
476 				mmio_megabytes * 1024 * 1024;
477 
478 	return 0;
479 
480 error:
481 	vmbus_close(hdev->channel);
482 	return ret;
483 }
484 
485 /* Send VRAM and Situation messages to the host */
486 static int synthvid_send_config(struct hv_device *hdev)
487 {
488 	struct fb_info *info = hv_get_drvdata(hdev);
489 	struct hvfb_par *par = info->par;
490 	struct synthvid_msg *msg = (struct synthvid_msg *)par->init_buf;
491 	int t, ret = 0;
492 
493 	/* Send VRAM location */
494 	memset(msg, 0, sizeof(struct synthvid_msg));
495 	msg->vid_hdr.type = SYNTHVID_VRAM_LOCATION;
496 	msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
497 		sizeof(struct synthvid_vram_location);
498 	msg->vram.user_ctx = msg->vram.vram_gpa = info->fix.smem_start;
499 	msg->vram.is_vram_gpa_specified = 1;
500 	synthvid_send(hdev, msg);
501 
502 	t = wait_for_completion_timeout(&par->wait, VSP_TIMEOUT);
503 	if (!t) {
504 		pr_err("Time out on waiting vram location ack\n");
505 		ret = -ETIMEDOUT;
506 		goto out;
507 	}
508 	if (msg->vram_ack.user_ctx != info->fix.smem_start) {
509 		pr_err("Unable to set VRAM location\n");
510 		ret = -ENODEV;
511 		goto out;
512 	}
513 
514 	/* Send pointer and situation update */
515 	synthvid_send_ptr(hdev);
516 	synthvid_send_situ(hdev);
517 
518 out:
519 	return ret;
520 }
521 
522 
523 /*
524  * Delayed work callback:
525  * It is called at HVFB_UPDATE_DELAY or longer time interval to process
526  * screen updates. It is re-scheduled if further update is necessary.
527  */
528 static void hvfb_update_work(struct work_struct *w)
529 {
530 	struct hvfb_par *par = container_of(w, struct hvfb_par, dwork.work);
531 	struct fb_info *info = par->info;
532 
533 	if (par->fb_ready)
534 		synthvid_update(info);
535 
536 	if (par->update)
537 		schedule_delayed_work(&par->dwork, HVFB_UPDATE_DELAY);
538 }
539 
540 static int hvfb_on_panic(struct notifier_block *nb,
541 			 unsigned long e, void *p)
542 {
543 	struct hvfb_par *par;
544 	struct fb_info *info;
545 
546 	par = container_of(nb, struct hvfb_par, hvfb_panic_nb);
547 	par->synchronous_fb = true;
548 	info = par->info;
549 	synthvid_update(info);
550 
551 	return NOTIFY_DONE;
552 }
553 
554 /* Framebuffer operation handlers */
555 
556 static int hvfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
557 {
558 	if (var->xres < HVFB_WIDTH_MIN || var->yres < HVFB_HEIGHT_MIN ||
559 	    var->xres > screen_width || var->yres >  screen_height ||
560 	    var->bits_per_pixel != screen_depth)
561 		return -EINVAL;
562 
563 	var->xres_virtual = var->xres;
564 	var->yres_virtual = var->yres;
565 
566 	return 0;
567 }
568 
569 static int hvfb_set_par(struct fb_info *info)
570 {
571 	struct hv_device *hdev = device_to_hv_device(info->device);
572 
573 	return synthvid_send_situ(hdev);
574 }
575 
576 
577 static inline u32 chan_to_field(u32 chan, struct fb_bitfield *bf)
578 {
579 	return ((chan & 0xffff) >> (16 - bf->length)) << bf->offset;
580 }
581 
582 static int hvfb_setcolreg(unsigned regno, unsigned red, unsigned green,
583 			  unsigned blue, unsigned transp, struct fb_info *info)
584 {
585 	u32 *pal = info->pseudo_palette;
586 
587 	if (regno > 15)
588 		return -EINVAL;
589 
590 	pal[regno] = chan_to_field(red, &info->var.red)
591 		| chan_to_field(green, &info->var.green)
592 		| chan_to_field(blue, &info->var.blue)
593 		| chan_to_field(transp, &info->var.transp);
594 
595 	return 0;
596 }
597 
598 static int hvfb_blank(int blank, struct fb_info *info)
599 {
600 	return 1;	/* get fb_blank to set the colormap to all black */
601 }
602 
603 static void hvfb_cfb_fillrect(struct fb_info *p,
604 			      const struct fb_fillrect *rect)
605 {
606 	struct hvfb_par *par = p->par;
607 
608 	cfb_fillrect(p, rect);
609 	if (par->synchronous_fb)
610 		synthvid_update(p);
611 }
612 
613 static void hvfb_cfb_copyarea(struct fb_info *p,
614 			      const struct fb_copyarea *area)
615 {
616 	struct hvfb_par *par = p->par;
617 
618 	cfb_copyarea(p, area);
619 	if (par->synchronous_fb)
620 		synthvid_update(p);
621 }
622 
623 static void hvfb_cfb_imageblit(struct fb_info *p,
624 			       const struct fb_image *image)
625 {
626 	struct hvfb_par *par = p->par;
627 
628 	cfb_imageblit(p, image);
629 	if (par->synchronous_fb)
630 		synthvid_update(p);
631 }
632 
633 static struct fb_ops hvfb_ops = {
634 	.owner = THIS_MODULE,
635 	.fb_check_var = hvfb_check_var,
636 	.fb_set_par = hvfb_set_par,
637 	.fb_setcolreg = hvfb_setcolreg,
638 	.fb_fillrect = hvfb_cfb_fillrect,
639 	.fb_copyarea = hvfb_cfb_copyarea,
640 	.fb_imageblit = hvfb_cfb_imageblit,
641 	.fb_blank = hvfb_blank,
642 };
643 
644 
645 /* Get options from kernel paramenter "video=" */
646 static void hvfb_get_option(struct fb_info *info)
647 {
648 	struct hvfb_par *par = info->par;
649 	char *opt = NULL, *p;
650 	uint x = 0, y = 0;
651 
652 	if (fb_get_options(KBUILD_MODNAME, &opt) || !opt || !*opt)
653 		return;
654 
655 	p = strsep(&opt, "x");
656 	if (!*p || kstrtouint(p, 0, &x) ||
657 	    !opt || !*opt || kstrtouint(opt, 0, &y)) {
658 		pr_err("Screen option is invalid: skipped\n");
659 		return;
660 	}
661 
662 	if (x < HVFB_WIDTH_MIN || y < HVFB_HEIGHT_MIN ||
663 	    (par->synthvid_version == SYNTHVID_VERSION_WIN8 &&
664 	     x * y * screen_depth / 8 > SYNTHVID_FB_SIZE_WIN8) ||
665 	    (par->synthvid_version == SYNTHVID_VERSION_WIN7 &&
666 	     (x > SYNTHVID_WIDTH_MAX_WIN7 || y > SYNTHVID_HEIGHT_MAX_WIN7))) {
667 		pr_err("Screen resolution option is out of range: skipped\n");
668 		return;
669 	}
670 
671 	screen_width = x;
672 	screen_height = y;
673 	return;
674 }
675 
676 
677 /* Get framebuffer memory from Hyper-V video pci space */
678 static int hvfb_getmem(struct fb_info *info)
679 {
680 	struct hvfb_par *par = info->par;
681 	struct pci_dev *pdev  = NULL;
682 	void __iomem *fb_virt;
683 	int gen2vm = efi_enabled(EFI_BOOT);
684 	int ret;
685 
686 	par->mem.name = KBUILD_MODNAME;
687 	par->mem.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
688 	if (gen2vm) {
689 		ret = allocate_resource(&hyperv_mmio, &par->mem,
690 					screen_fb_size,
691 					0, -1,
692 					screen_fb_size,
693 					NULL, NULL);
694 		if (ret != 0) {
695 			pr_err("Unable to allocate framebuffer memory\n");
696 			return -ENODEV;
697 		}
698 	} else {
699 		pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT,
700 			      PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
701 		if (!pdev) {
702 			pr_err("Unable to find PCI Hyper-V video\n");
703 			return -ENODEV;
704 		}
705 
706 		if (!(pci_resource_flags(pdev, 0) & IORESOURCE_MEM) ||
707 		    pci_resource_len(pdev, 0) < screen_fb_size)
708 			goto err1;
709 
710 		par->mem.end = pci_resource_end(pdev, 0);
711 		par->mem.start = par->mem.end - screen_fb_size + 1;
712 		ret = request_resource(&pdev->resource[0], &par->mem);
713 		if (ret != 0) {
714 			pr_err("Unable to request framebuffer memory\n");
715 			goto err1;
716 		}
717 	}
718 
719 	fb_virt = ioremap(par->mem.start, screen_fb_size);
720 	if (!fb_virt)
721 		goto err2;
722 
723 	info->apertures = alloc_apertures(1);
724 	if (!info->apertures)
725 		goto err3;
726 
727 	if (gen2vm) {
728 		info->apertures->ranges[0].base = screen_info.lfb_base;
729 		info->apertures->ranges[0].size = screen_info.lfb_size;
730 		remove_conflicting_framebuffers(info->apertures,
731 						KBUILD_MODNAME, false);
732 	} else {
733 		info->apertures->ranges[0].base = pci_resource_start(pdev, 0);
734 		info->apertures->ranges[0].size = pci_resource_len(pdev, 0);
735 	}
736 
737 	info->fix.smem_start = par->mem.start;
738 	info->fix.smem_len = screen_fb_size;
739 	info->screen_base = fb_virt;
740 	info->screen_size = screen_fb_size;
741 
742 	if (!gen2vm)
743 		pci_dev_put(pdev);
744 
745 	return 0;
746 
747 err3:
748 	iounmap(fb_virt);
749 err2:
750 	release_resource(&par->mem);
751 err1:
752 	if (!gen2vm)
753 		pci_dev_put(pdev);
754 
755 	return -ENOMEM;
756 }
757 
758 /* Release the framebuffer */
759 static void hvfb_putmem(struct fb_info *info)
760 {
761 	struct hvfb_par *par = info->par;
762 
763 	iounmap(info->screen_base);
764 	release_resource(&par->mem);
765 }
766 
767 
768 static int hvfb_probe(struct hv_device *hdev,
769 		      const struct hv_vmbus_device_id *dev_id)
770 {
771 	struct fb_info *info;
772 	struct hvfb_par *par;
773 	int ret;
774 
775 	info = framebuffer_alloc(sizeof(struct hvfb_par), &hdev->device);
776 	if (!info) {
777 		pr_err("No memory for framebuffer info\n");
778 		return -ENOMEM;
779 	}
780 
781 	par = info->par;
782 	par->info = info;
783 	par->fb_ready = false;
784 	init_completion(&par->wait);
785 	INIT_DELAYED_WORK(&par->dwork, hvfb_update_work);
786 
787 	/* Connect to VSP */
788 	hv_set_drvdata(hdev, info);
789 	ret = synthvid_connect_vsp(hdev);
790 	if (ret) {
791 		pr_err("Unable to connect to VSP\n");
792 		goto error1;
793 	}
794 
795 	ret = hvfb_getmem(info);
796 	if (ret) {
797 		pr_err("No memory for framebuffer\n");
798 		goto error2;
799 	}
800 
801 	hvfb_get_option(info);
802 	pr_info("Screen resolution: %dx%d, Color depth: %d\n",
803 		screen_width, screen_height, screen_depth);
804 
805 
806 	/* Set up fb_info */
807 	info->flags = FBINFO_DEFAULT;
808 
809 	info->var.xres_virtual = info->var.xres = screen_width;
810 	info->var.yres_virtual = info->var.yres = screen_height;
811 	info->var.bits_per_pixel = screen_depth;
812 
813 	if (info->var.bits_per_pixel == 16) {
814 		info->var.red = (struct fb_bitfield){11, 5, 0};
815 		info->var.green = (struct fb_bitfield){5, 6, 0};
816 		info->var.blue = (struct fb_bitfield){0, 5, 0};
817 		info->var.transp = (struct fb_bitfield){0, 0, 0};
818 	} else {
819 		info->var.red = (struct fb_bitfield){16, 8, 0};
820 		info->var.green = (struct fb_bitfield){8, 8, 0};
821 		info->var.blue = (struct fb_bitfield){0, 8, 0};
822 		info->var.transp = (struct fb_bitfield){24, 8, 0};
823 	}
824 
825 	info->var.activate = FB_ACTIVATE_NOW;
826 	info->var.height = -1;
827 	info->var.width = -1;
828 	info->var.vmode = FB_VMODE_NONINTERLACED;
829 
830 	strcpy(info->fix.id, KBUILD_MODNAME);
831 	info->fix.type = FB_TYPE_PACKED_PIXELS;
832 	info->fix.visual = FB_VISUAL_TRUECOLOR;
833 	info->fix.line_length = screen_width * screen_depth / 8;
834 	info->fix.accel = FB_ACCEL_NONE;
835 
836 	info->fbops = &hvfb_ops;
837 	info->pseudo_palette = par->pseudo_palette;
838 
839 	/* Send config to host */
840 	ret = synthvid_send_config(hdev);
841 	if (ret)
842 		goto error;
843 
844 	ret = register_framebuffer(info);
845 	if (ret) {
846 		pr_err("Unable to register framebuffer\n");
847 		goto error;
848 	}
849 
850 	par->fb_ready = true;
851 
852 	par->synchronous_fb = false;
853 	par->hvfb_panic_nb.notifier_call = hvfb_on_panic;
854 	atomic_notifier_chain_register(&panic_notifier_list,
855 				       &par->hvfb_panic_nb);
856 
857 	return 0;
858 
859 error:
860 	hvfb_putmem(info);
861 error2:
862 	vmbus_close(hdev->channel);
863 error1:
864 	cancel_delayed_work_sync(&par->dwork);
865 	hv_set_drvdata(hdev, NULL);
866 	framebuffer_release(info);
867 	return ret;
868 }
869 
870 
871 static int hvfb_remove(struct hv_device *hdev)
872 {
873 	struct fb_info *info = hv_get_drvdata(hdev);
874 	struct hvfb_par *par = info->par;
875 
876 	atomic_notifier_chain_unregister(&panic_notifier_list,
877 					 &par->hvfb_panic_nb);
878 
879 	par->update = false;
880 	par->fb_ready = false;
881 
882 	unregister_framebuffer(info);
883 	cancel_delayed_work_sync(&par->dwork);
884 
885 	vmbus_close(hdev->channel);
886 	hv_set_drvdata(hdev, NULL);
887 
888 	hvfb_putmem(info);
889 	framebuffer_release(info);
890 
891 	return 0;
892 }
893 
894 
895 static const struct pci_device_id pci_stub_id_table[] = {
896 	{
897 		.vendor      = PCI_VENDOR_ID_MICROSOFT,
898 		.device      = PCI_DEVICE_ID_HYPERV_VIDEO,
899 	},
900 	{ /* end of list */ }
901 };
902 
903 static const struct hv_vmbus_device_id id_table[] = {
904 	/* Synthetic Video Device GUID */
905 	{HV_SYNTHVID_GUID},
906 	{}
907 };
908 
909 MODULE_DEVICE_TABLE(pci, pci_stub_id_table);
910 MODULE_DEVICE_TABLE(vmbus, id_table);
911 
912 static struct hv_driver hvfb_drv = {
913 	.name = KBUILD_MODNAME,
914 	.id_table = id_table,
915 	.probe = hvfb_probe,
916 	.remove = hvfb_remove,
917 };
918 
919 static int hvfb_pci_stub_probe(struct pci_dev *pdev,
920 			       const struct pci_device_id *ent)
921 {
922 	return 0;
923 }
924 
925 static void hvfb_pci_stub_remove(struct pci_dev *pdev)
926 {
927 }
928 
929 static struct pci_driver hvfb_pci_stub_driver = {
930 	.name =		KBUILD_MODNAME,
931 	.id_table =	pci_stub_id_table,
932 	.probe =	hvfb_pci_stub_probe,
933 	.remove =	hvfb_pci_stub_remove,
934 };
935 
936 static int __init hvfb_drv_init(void)
937 {
938 	int ret;
939 
940 	ret = vmbus_driver_register(&hvfb_drv);
941 	if (ret != 0)
942 		return ret;
943 
944 	ret = pci_register_driver(&hvfb_pci_stub_driver);
945 	if (ret != 0) {
946 		vmbus_driver_unregister(&hvfb_drv);
947 		return ret;
948 	}
949 
950 	return 0;
951 }
952 
953 static void __exit hvfb_drv_exit(void)
954 {
955 	pci_unregister_driver(&hvfb_pci_stub_driver);
956 	vmbus_driver_unregister(&hvfb_drv);
957 }
958 
959 module_init(hvfb_drv_init);
960 module_exit(hvfb_drv_exit);
961 
962 MODULE_LICENSE("GPL");
963 MODULE_DESCRIPTION("Microsoft Hyper-V Synthetic Video Frame Buffer Driver");
964