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Linux 4.16.11
[linux/fpc-iii.git] / drivers / video / fbdev / xen-fbfront.c
blob46f63960fa9e6aa2913be8b804c1de24ce1245be
1 /*
2 * Xen para-virtual frame buffer device
3 *
4 * Copyright (C) 2005-2006 Anthony Liguori <aliguori@us.ibm.com>
5 * Copyright (C) 2006-2008 Red Hat, Inc., Markus Armbruster <armbru@redhat.com>
6 *
7 * Based on linux/drivers/video/q40fb.c
8 *
9 * This file is subject to the terms and conditions of the GNU General Public
10 * License. See the file COPYING in the main directory of this archive for
11 * more details.
12 */
13
14 /*
15 * TODO:
16 *
17 * Switch to grant tables when they become capable of dealing with the
18 * frame buffer.
19 */
20
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22
23 #include <linux/console.h>
24 #include <linux/kernel.h>
25 #include <linux/errno.h>
26 #include <linux/fb.h>
27 #include <linux/module.h>
28 #include <linux/slab.h>
29 #include <linux/vmalloc.h>
30 #include <linux/mm.h>
31
32 #include <asm/xen/hypervisor.h>
33
34 #include <xen/xen.h>
35 #include <xen/events.h>
36 #include <xen/page.h>
37 #include <xen/interface/io/fbif.h>
38 #include <xen/interface/io/protocols.h>
39 #include <xen/xenbus.h>
40 #include <xen/platform_pci.h>
41
42 struct xenfb_info {
43 unsigned char *fb;
44 struct fb_info *fb_info;
45 int x1, y1, x2, y2; /* dirty rectangle,
46 protected by dirty_lock */
47 spinlock_t dirty_lock;
48 int nr_pages;
49 int irq;
50 struct xenfb_page *page;
51 unsigned long *gfns;
52 int update_wanted; /* XENFB_TYPE_UPDATE wanted */
53 int feature_resize; /* XENFB_TYPE_RESIZE ok */
54 struct xenfb_resize resize; /* protected by resize_lock */
55 int resize_dpy; /* ditto */
56 spinlock_t resize_lock;
57
58 struct xenbus_device *xbdev;
59 };
60
61 #define XENFB_DEFAULT_FB_LEN (XENFB_WIDTH * XENFB_HEIGHT * XENFB_DEPTH / 8)
62
63 enum { KPARAM_MEM, KPARAM_WIDTH, KPARAM_HEIGHT, KPARAM_CNT };
64 static int video[KPARAM_CNT] = { 2, XENFB_WIDTH, XENFB_HEIGHT };
65 module_param_array(video, int, NULL, 0);
66 MODULE_PARM_DESC(video,
67 "Video memory size in MB, width, height in pixels (default 2,800,600)");
68
69 static void xenfb_make_preferred_console(void);
70 static int xenfb_remove(struct xenbus_device *);
71 static void xenfb_init_shared_page(struct xenfb_info *, struct fb_info *);
72 static int xenfb_connect_backend(struct xenbus_device *, struct xenfb_info *);
73 static void xenfb_disconnect_backend(struct xenfb_info *);
74
75 static void xenfb_send_event(struct xenfb_info *info,
76 union xenfb_out_event *event)
77 {
78 u32 prod;
79
80 prod = info->page->out_prod;
81 /* caller ensures !xenfb_queue_full() */
82 mb(); /* ensure ring space available */
83 XENFB_OUT_RING_REF(info->page, prod) = *event;
84 wmb(); /* ensure ring contents visible */
85 info->page->out_prod = prod + 1;
86
87 notify_remote_via_irq(info->irq);
88 }
89
90 static void xenfb_do_update(struct xenfb_info *info,
91 int x, int y, int w, int h)
92 {
93 union xenfb_out_event event;
94
95 memset(&event, 0, sizeof(event));
96 event.type = XENFB_TYPE_UPDATE;
97 event.update.x = x;
98 event.update.y = y;
99 event.update.width = w;
100 event.update.height = h;
101
102 /* caller ensures !xenfb_queue_full() */
103 xenfb_send_event(info, &event);
104 }
105
106 static void xenfb_do_resize(struct xenfb_info *info)
107 {
108 union xenfb_out_event event;
109
110 memset(&event, 0, sizeof(event));
111 event.resize = info->resize;
112
113 /* caller ensures !xenfb_queue_full() */
114 xenfb_send_event(info, &event);
115 }
116
117 static int xenfb_queue_full(struct xenfb_info *info)
118 {
119 u32 cons, prod;
120
121 prod = info->page->out_prod;
122 cons = info->page->out_cons;
123 return prod - cons == XENFB_OUT_RING_LEN;
124 }
125
126 static void xenfb_handle_resize_dpy(struct xenfb_info *info)
127 {
128 unsigned long flags;
129
130 spin_lock_irqsave(&info->resize_lock, flags);
131 if (info->resize_dpy) {
132 if (!xenfb_queue_full(info)) {
133 info->resize_dpy = 0;
134 xenfb_do_resize(info);
135 }
136 }
137 spin_unlock_irqrestore(&info->resize_lock, flags);
138 }
139
140 static void xenfb_refresh(struct xenfb_info *info,
141 int x1, int y1, int w, int h)
142 {
143 unsigned long flags;
144 int x2 = x1 + w - 1;
145 int y2 = y1 + h - 1;
146
147 xenfb_handle_resize_dpy(info);
148
149 if (!info->update_wanted)
150 return;
151
152 spin_lock_irqsave(&info->dirty_lock, flags);
153
154 /* Combine with dirty rectangle: */
155 if (info->y1 < y1)
156 y1 = info->y1;
157 if (info->y2 > y2)
158 y2 = info->y2;
159 if (info->x1 < x1)
160 x1 = info->x1;
161 if (info->x2 > x2)
162 x2 = info->x2;
163
164 if (xenfb_queue_full(info)) {
165 /* Can't send right now, stash it in the dirty rectangle */
166 info->x1 = x1;
167 info->x2 = x2;
168 info->y1 = y1;
169 info->y2 = y2;
170 spin_unlock_irqrestore(&info->dirty_lock, flags);
171 return;
172 }
173
174 /* Clear dirty rectangle: */
175 info->x1 = info->y1 = INT_MAX;
176 info->x2 = info->y2 = 0;
177
178 spin_unlock_irqrestore(&info->dirty_lock, flags);
179
180 if (x1 <= x2 && y1 <= y2)
181 xenfb_do_update(info, x1, y1, x2 - x1 + 1, y2 - y1 + 1);
182 }
183
184 static void xenfb_deferred_io(struct fb_info *fb_info,
185 struct list_head *pagelist)
186 {
187 struct xenfb_info *info = fb_info->par;
188 struct page *page;
189 unsigned long beg, end;
190 int y1, y2, miny, maxy;
191
192 miny = INT_MAX;
193 maxy = 0;
194 list_for_each_entry(page, pagelist, lru) {
195 beg = page->index << PAGE_SHIFT;
196 end = beg + PAGE_SIZE - 1;
197 y1 = beg / fb_info->fix.line_length;
198 y2 = end / fb_info->fix.line_length;
199 if (y2 >= fb_info->var.yres)
200 y2 = fb_info->var.yres - 1;
201 if (miny > y1)
202 miny = y1;
203 if (maxy < y2)
204 maxy = y2;
205 }
206 xenfb_refresh(info, 0, miny, fb_info->var.xres, maxy - miny + 1);
207 }
208
209 static struct fb_deferred_io xenfb_defio = {
210 .delay = HZ / 20,
211 .deferred_io = xenfb_deferred_io,
212 };
213
214 static int xenfb_setcolreg(unsigned regno, unsigned red, unsigned green,
215 unsigned blue, unsigned transp,
216 struct fb_info *info)
217 {
218 u32 v;
219
220 if (regno > info->cmap.len)
221 return 1;
222
223 #define CNVT_TOHW(val, width) ((((val)<<(width))+0x7FFF-(val))>>16)
224 red = CNVT_TOHW(red, info->var.red.length);
225 green = CNVT_TOHW(green, info->var.green.length);
226 blue = CNVT_TOHW(blue, info->var.blue.length);
227 transp = CNVT_TOHW(transp, info->var.transp.length);
228 #undef CNVT_TOHW
229
230 v = (red << info->var.red.offset) |
231 (green << info->var.green.offset) |
232 (blue << info->var.blue.offset);
233
234 switch (info->var.bits_per_pixel) {
235 case 16:
236 case 24:
237 case 32:
238 ((u32 *)info->pseudo_palette)[regno] = v;
239 break;
240 }
241
242 return 0;
243 }
244
245 static void xenfb_fillrect(struct fb_info *p, const struct fb_fillrect *rect)
246 {
247 struct xenfb_info *info = p->par;
248
249 sys_fillrect(p, rect);
250 xenfb_refresh(info, rect->dx, rect->dy, rect->width, rect->height);
251 }
252
253 static void xenfb_imageblit(struct fb_info *p, const struct fb_image *image)
254 {
255 struct xenfb_info *info = p->par;
256
257 sys_imageblit(p, image);
258 xenfb_refresh(info, image->dx, image->dy, image->width, image->height);
259 }
260
261 static void xenfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
262 {
263 struct xenfb_info *info = p->par;
264
265 sys_copyarea(p, area);
266 xenfb_refresh(info, area->dx, area->dy, area->width, area->height);
267 }
268
269 static ssize_t xenfb_write(struct fb_info *p, const char __user *buf,
270 size_t count, loff_t *ppos)
271 {
272 struct xenfb_info *info = p->par;
273 ssize_t res;
274
275 res = fb_sys_write(p, buf, count, ppos);
276 xenfb_refresh(info, 0, 0, info->page->width, info->page->height);
277 return res;
278 }
279
280 static int
281 xenfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
282 {
283 struct xenfb_info *xenfb_info;
284 int required_mem_len;
285
286 xenfb_info = info->par;
287
288 if (!xenfb_info->feature_resize) {
289 if (var->xres == video[KPARAM_WIDTH] &&
290 var->yres == video[KPARAM_HEIGHT] &&
291 var->bits_per_pixel == xenfb_info->page->depth) {
292 return 0;
293 }
294 return -EINVAL;
295 }
296
297 /* Can't resize past initial width and height */
298 if (var->xres > video[KPARAM_WIDTH] || var->yres > video[KPARAM_HEIGHT])
299 return -EINVAL;
300
301 required_mem_len = var->xres * var->yres * xenfb_info->page->depth / 8;
302 if (var->bits_per_pixel == xenfb_info->page->depth &&
303 var->xres <= info->fix.line_length / (XENFB_DEPTH / 8) &&
304 required_mem_len <= info->fix.smem_len) {
305 var->xres_virtual = var->xres;
306 var->yres_virtual = var->yres;
307 return 0;
308 }
309 return -EINVAL;
310 }
311
312 static int xenfb_set_par(struct fb_info *info)
313 {
314 struct xenfb_info *xenfb_info;
315 unsigned long flags;
316
317 xenfb_info = info->par;
318
319 spin_lock_irqsave(&xenfb_info->resize_lock, flags);
320 xenfb_info->resize.type = XENFB_TYPE_RESIZE;
321 xenfb_info->resize.width = info->var.xres;
322 xenfb_info->resize.height = info->var.yres;
323 xenfb_info->resize.stride = info->fix.line_length;
324 xenfb_info->resize.depth = info->var.bits_per_pixel;
325 xenfb_info->resize.offset = 0;
326 xenfb_info->resize_dpy = 1;
327 spin_unlock_irqrestore(&xenfb_info->resize_lock, flags);
328 return 0;
329 }
330
331 static struct fb_ops xenfb_fb_ops = {
332 .owner = THIS_MODULE,
333 .fb_read = fb_sys_read,
334 .fb_write = xenfb_write,
335 .fb_setcolreg = xenfb_setcolreg,
336 .fb_fillrect = xenfb_fillrect,
337 .fb_copyarea = xenfb_copyarea,
338 .fb_imageblit = xenfb_imageblit,
339 .fb_check_var = xenfb_check_var,
340 .fb_set_par = xenfb_set_par,
341 };
342
343 static irqreturn_t xenfb_event_handler(int rq, void *dev_id)
344 {
345 /*
346 * No in events recognized, simply ignore them all.
347 * If you need to recognize some, see xen-kbdfront's
348 * input_handler() for how to do that.
349 */
350 struct xenfb_info *info = dev_id;
351 struct xenfb_page *page = info->page;
352
353 if (page->in_cons != page->in_prod) {
354 info->page->in_cons = info->page->in_prod;
355 notify_remote_via_irq(info->irq);
356 }
357
358 /* Flush dirty rectangle: */
359 xenfb_refresh(info, INT_MAX, INT_MAX, -INT_MAX, -INT_MAX);
360
361 return IRQ_HANDLED;
362 }
363
364 static int xenfb_probe(struct xenbus_device *dev,
365 const struct xenbus_device_id *id)
366 {
367 struct xenfb_info *info;
368 struct fb_info *fb_info;
369 int fb_size;
370 int val;
371 int ret = 0;
372
373 info = kzalloc(sizeof(*info), GFP_KERNEL);
374 if (info == NULL) {
375 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
376 return -ENOMEM;
377 }
378
379 /* Limit kernel param videoram amount to what is in xenstore */
380 if (xenbus_scanf(XBT_NIL, dev->otherend, "videoram", "%d", &val) == 1) {
381 if (val < video[KPARAM_MEM])
382 video[KPARAM_MEM] = val;
383 }
384
385 video[KPARAM_WIDTH] = xenbus_read_unsigned(dev->otherend, "width",
386 video[KPARAM_WIDTH]);
387 video[KPARAM_HEIGHT] = xenbus_read_unsigned(dev->otherend, "height",
388 video[KPARAM_HEIGHT]);
389
390 /* If requested res does not fit in available memory, use default */
391 fb_size = video[KPARAM_MEM] * 1024 * 1024;
392 if (video[KPARAM_WIDTH] * video[KPARAM_HEIGHT] * XENFB_DEPTH / 8
393 > fb_size) {
394 pr_warn("display parameters %d,%d,%d invalid, use defaults\n",
395 video[KPARAM_MEM], video[KPARAM_WIDTH],
396 video[KPARAM_HEIGHT]);
397 video[KPARAM_WIDTH] = XENFB_WIDTH;
398 video[KPARAM_HEIGHT] = XENFB_HEIGHT;
399 fb_size = XENFB_DEFAULT_FB_LEN;
400 }
401
402 dev_set_drvdata(&dev->dev, info);
403 info->xbdev = dev;
404 info->irq = -1;
405 info->x1 = info->y1 = INT_MAX;
406 spin_lock_init(&info->dirty_lock);
407 spin_lock_init(&info->resize_lock);
408
409 info->fb = vzalloc(fb_size);
410 if (info->fb == NULL)
411 goto error_nomem;
412
413 info->nr_pages = (fb_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
414
415 info->gfns = vmalloc(sizeof(unsigned long) * info->nr_pages);
416 if (!info->gfns)
417 goto error_nomem;
418
419 /* set up shared page */
420 info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
421 if (!info->page)
422 goto error_nomem;
423
424 /* abusing framebuffer_alloc() to allocate pseudo_palette */
425 fb_info = framebuffer_alloc(sizeof(u32) * 256, NULL);
426 if (fb_info == NULL)
427 goto error_nomem;
428
429 /* complete the abuse: */
430 fb_info->pseudo_palette = fb_info->par;
431 fb_info->par = info;
432
433 fb_info->screen_base = info->fb;
434
435 fb_info->fbops = &xenfb_fb_ops;
436 fb_info->var.xres_virtual = fb_info->var.xres = video[KPARAM_WIDTH];
437 fb_info->var.yres_virtual = fb_info->var.yres = video[KPARAM_HEIGHT];
438 fb_info->var.bits_per_pixel = XENFB_DEPTH;
439
440 fb_info->var.red = (struct fb_bitfield){16, 8, 0};
441 fb_info->var.green = (struct fb_bitfield){8, 8, 0};
442 fb_info->var.blue = (struct fb_bitfield){0, 8, 0};
443
444 fb_info->var.activate = FB_ACTIVATE_NOW;
445 fb_info->var.height = -1;
446 fb_info->var.width = -1;
447 fb_info->var.vmode = FB_VMODE_NONINTERLACED;
448
449 fb_info->fix.visual = FB_VISUAL_TRUECOLOR;
450 fb_info->fix.line_length = fb_info->var.xres * XENFB_DEPTH / 8;
451 fb_info->fix.smem_start = 0;
452 fb_info->fix.smem_len = fb_size;
453 strcpy(fb_info->fix.id, "xen");
454 fb_info->fix.type = FB_TYPE_PACKED_PIXELS;
455 fb_info->fix.accel = FB_ACCEL_NONE;
456
457 fb_info->flags = FBINFO_FLAG_DEFAULT | FBINFO_VIRTFB;
458
459 ret = fb_alloc_cmap(&fb_info->cmap, 256, 0);
460 if (ret < 0) {
461 framebuffer_release(fb_info);
462 xenbus_dev_fatal(dev, ret, "fb_alloc_cmap");
463 goto error;
464 }
465
466 fb_info->fbdefio = &xenfb_defio;
467 fb_deferred_io_init(fb_info);
468
469 xenfb_init_shared_page(info, fb_info);
470
471 ret = xenfb_connect_backend(dev, info);
472 if (ret < 0) {
473 xenbus_dev_fatal(dev, ret, "xenfb_connect_backend");
474 goto error_fb;
475 }
476
477 ret = register_framebuffer(fb_info);
478 if (ret) {
479 xenbus_dev_fatal(dev, ret, "register_framebuffer");
480 goto error_fb;
481 }
482 info->fb_info = fb_info;
483
484 xenfb_make_preferred_console();
485 return 0;
486
487 error_fb:
488 fb_deferred_io_cleanup(fb_info);
489 fb_dealloc_cmap(&fb_info->cmap);
490 framebuffer_release(fb_info);
491 error_nomem:
492 if (!ret) {
493 ret = -ENOMEM;
494 xenbus_dev_fatal(dev, ret, "allocating device memory");
495 }
496 error:
497 xenfb_remove(dev);
498 return ret;
499 }
500
501 static void xenfb_make_preferred_console(void)
502 {
503 struct console *c;
504
505 if (console_set_on_cmdline)
506 return;
507
508 console_lock();
509 for_each_console(c) {
510 if (!strcmp(c->name, "tty") && c->index == 0)
511 break;
512 }
513 console_unlock();
514 if (c) {
515 unregister_console(c);
516 c->flags |= CON_CONSDEV;
517 c->flags &= ~CON_PRINTBUFFER; /* don't print again */
518 register_console(c);
519 }
520 }
521
522 static int xenfb_resume(struct xenbus_device *dev)
523 {
524 struct xenfb_info *info = dev_get_drvdata(&dev->dev);
525
526 xenfb_disconnect_backend(info);
527 xenfb_init_shared_page(info, info->fb_info);
528 return xenfb_connect_backend(dev, info);
529 }
530
531 static int xenfb_remove(struct xenbus_device *dev)
532 {
533 struct xenfb_info *info = dev_get_drvdata(&dev->dev);
534
535 xenfb_disconnect_backend(info);
536 if (info->fb_info) {
537 fb_deferred_io_cleanup(info->fb_info);
538 unregister_framebuffer(info->fb_info);
539 fb_dealloc_cmap(&info->fb_info->cmap);
540 framebuffer_release(info->fb_info);
541 }
542 free_page((unsigned long)info->page);
543 vfree(info->gfns);
544 vfree(info->fb);
545 kfree(info);
546
547 return 0;
548 }
549
550 static unsigned long vmalloc_to_gfn(void *address)
551 {
552 return xen_page_to_gfn(vmalloc_to_page(address));
553 }
554
555 static void xenfb_init_shared_page(struct xenfb_info *info,
556 struct fb_info *fb_info)
557 {
558 int i;
559 int epd = PAGE_SIZE / sizeof(info->gfns[0]);
560
561 for (i = 0; i < info->nr_pages; i++)
562 info->gfns[i] = vmalloc_to_gfn(info->fb + i * PAGE_SIZE);
563
564 for (i = 0; i * epd < info->nr_pages; i++)
565 info->page->pd[i] = vmalloc_to_gfn(&info->gfns[i * epd]);
566
567 info->page->width = fb_info->var.xres;
568 info->page->height = fb_info->var.yres;
569 info->page->depth = fb_info->var.bits_per_pixel;
570 info->page->line_length = fb_info->fix.line_length;
571 info->page->mem_length = fb_info->fix.smem_len;
572 info->page->in_cons = info->page->in_prod = 0;
573 info->page->out_cons = info->page->out_prod = 0;
574 }
575
576 static int xenfb_connect_backend(struct xenbus_device *dev,
577 struct xenfb_info *info)
578 {
579 int ret, evtchn, irq;
580 struct xenbus_transaction xbt;
581
582 ret = xenbus_alloc_evtchn(dev, &evtchn);
583 if (ret)
584 return ret;
585 irq = bind_evtchn_to_irqhandler(evtchn, xenfb_event_handler,
586 0, dev->devicetype, info);
587 if (irq < 0) {
588 xenbus_free_evtchn(dev, evtchn);
589 xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
590 return irq;
591 }
592 again:
593 ret = xenbus_transaction_start(&xbt);
594 if (ret) {
595 xenbus_dev_fatal(dev, ret, "starting transaction");
596 goto unbind_irq;
597 }
598 ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
599 virt_to_gfn(info->page));
600 if (ret)
601 goto error_xenbus;
602 ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
603 evtchn);
604 if (ret)
605 goto error_xenbus;
606 ret = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
607 XEN_IO_PROTO_ABI_NATIVE);
608 if (ret)
609 goto error_xenbus;
610 ret = xenbus_printf(xbt, dev->nodename, "feature-update", "1");
611 if (ret)
612 goto error_xenbus;
613 ret = xenbus_transaction_end(xbt, 0);
614 if (ret) {
615 if (ret == -EAGAIN)
616 goto again;
617 xenbus_dev_fatal(dev, ret, "completing transaction");
618 goto unbind_irq;
619 }
620
621 xenbus_switch_state(dev, XenbusStateInitialised);
622 info->irq = irq;
623 return 0;
624
625 error_xenbus:
626 xenbus_transaction_end(xbt, 1);
627 xenbus_dev_fatal(dev, ret, "writing xenstore");
628 unbind_irq:
629 unbind_from_irqhandler(irq, info);
630 return ret;
631 }
632
633 static void xenfb_disconnect_backend(struct xenfb_info *info)
634 {
635 /* Prevent xenfb refresh */
636 info->update_wanted = 0;
637 if (info->irq >= 0)
638 unbind_from_irqhandler(info->irq, info);
639 info->irq = -1;
640 }
641
642 static void xenfb_backend_changed(struct xenbus_device *dev,
643 enum xenbus_state backend_state)
644 {
645 struct xenfb_info *info = dev_get_drvdata(&dev->dev);
646
647 switch (backend_state) {
648 case XenbusStateInitialising:
649 case XenbusStateInitialised:
650 case XenbusStateReconfiguring:
651 case XenbusStateReconfigured:
652 case XenbusStateUnknown:
653 break;
654
655 case XenbusStateInitWait:
656 xenbus_switch_state(dev, XenbusStateConnected);
657 break;
658
659 case XenbusStateConnected:
660 /*
661 * Work around xenbus race condition: If backend goes
662 * through InitWait to Connected fast enough, we can
663 * get Connected twice here.
664 */
665 if (dev->state != XenbusStateConnected)
666 /* no InitWait seen yet, fudge it */
667 xenbus_switch_state(dev, XenbusStateConnected);
668
669 if (xenbus_read_unsigned(info->xbdev->otherend,
670 "request-update", 0))
671 info->update_wanted = 1;
672
673 info->feature_resize = xenbus_read_unsigned(dev->otherend,
674 "feature-resize", 0);
675 break;
676
677 case XenbusStateClosed:
678 if (dev->state == XenbusStateClosed)
679 break;
680 /* Missed the backend's CLOSING state -- fallthrough */
681 case XenbusStateClosing:
682 xenbus_frontend_closed(dev);
683 break;
684 }
685 }
686
687 static const struct xenbus_device_id xenfb_ids[] = {
688 { "vfb" },
689 { "" }
690 };
691
692 static struct xenbus_driver xenfb_driver = {
693 .ids = xenfb_ids,
694 .probe = xenfb_probe,
695 .remove = xenfb_remove,
696 .resume = xenfb_resume,
697 .otherend_changed = xenfb_backend_changed,
698 };
699
700 static int __init xenfb_init(void)
701 {
702 if (!xen_domain())
703 return -ENODEV;
704
705 /* Nothing to do if running in dom0. */
706 if (xen_initial_domain())
707 return -ENODEV;
708
709 if (!xen_has_pv_devices())
710 return -ENODEV;
711
712 return xenbus_register_frontend(&xenfb_driver);
713 }
714
715 static void __exit xenfb_cleanup(void)
716 {
717 xenbus_unregister_driver(&xenfb_driver);
718 }
719
720 module_init(xenfb_init);
721 module_exit(xenfb_cleanup);
722
723 MODULE_DESCRIPTION("Xen virtual framebuffer device frontend");
724 MODULE_LICENSE("GPL");
725 MODULE_ALIAS("xen:vfb");
Linux with added FPC-III support