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 void 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
xenfb_send_event(struct xenfb_info * info,union xenfb_out_event * event)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
xenfb_do_update(struct xenfb_info * info,int x,int y,int w,int h)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
xenfb_do_resize(struct xenfb_info * info)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
xenfb_queue_full(struct xenfb_info * info)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
xenfb_handle_resize_dpy(struct xenfb_info * info)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
xenfb_refresh(struct xenfb_info * info,int x1,int y1,int w,int h)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
xenfb_deferred_io(struct fb_info * fb_info,struct list_head * pagereflist)184 static void xenfb_deferred_io(struct fb_info *fb_info, struct list_head *pagereflist)
185 {
186 struct xenfb_info *info = fb_info->par;
187 struct fb_deferred_io_pageref *pageref;
188 unsigned long beg, end;
189 int y1, y2, miny, maxy;
190
191 miny = INT_MAX;
192 maxy = 0;
193 list_for_each_entry(pageref, pagereflist, list) {
194 beg = pageref->offset;
195 end = beg + PAGE_SIZE - 1;
196 y1 = beg / fb_info->fix.line_length;
197 y2 = end / fb_info->fix.line_length;
198 if (y2 >= fb_info->var.yres)
199 y2 = fb_info->var.yres - 1;
200 if (miny > y1)
201 miny = y1;
202 if (maxy < y2)
203 maxy = y2;
204 }
205 xenfb_refresh(info, 0, miny, fb_info->var.xres, maxy - miny + 1);
206 }
207
208 static struct fb_deferred_io xenfb_defio = {
209 .delay = HZ / 20,
210 .deferred_io = xenfb_deferred_io,
211 };
212
xenfb_setcolreg(unsigned regno,unsigned red,unsigned green,unsigned blue,unsigned transp,struct fb_info * info)213 static int xenfb_setcolreg(unsigned regno, unsigned red, unsigned green,
214 unsigned blue, unsigned transp,
215 struct fb_info *info)
216 {
217 u32 v;
218
219 if (regno > info->cmap.len)
220 return 1;
221
222 #define CNVT_TOHW(val, width) ((((val)<<(width))+0x7FFF-(val))>>16)
223 red = CNVT_TOHW(red, info->var.red.length);
224 green = CNVT_TOHW(green, info->var.green.length);
225 blue = CNVT_TOHW(blue, info->var.blue.length);
226 #undef CNVT_TOHW
227
228 v = (red << info->var.red.offset) |
229 (green << info->var.green.offset) |
230 (blue << info->var.blue.offset);
231
232 switch (info->var.bits_per_pixel) {
233 case 16:
234 case 24:
235 case 32:
236 ((u32 *)info->pseudo_palette)[regno] = v;
237 break;
238 }
239
240 return 0;
241 }
242
243 static int
xenfb_check_var(struct fb_var_screeninfo * var,struct fb_info * info)244 xenfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
245 {
246 struct xenfb_info *xenfb_info;
247 int required_mem_len;
248
249 xenfb_info = info->par;
250
251 if (!xenfb_info->feature_resize) {
252 if (var->xres == video[KPARAM_WIDTH] &&
253 var->yres == video[KPARAM_HEIGHT] &&
254 var->bits_per_pixel == xenfb_info->page->depth) {
255 return 0;
256 }
257 return -EINVAL;
258 }
259
260 /* Can't resize past initial width and height */
261 if (var->xres > video[KPARAM_WIDTH] || var->yres > video[KPARAM_HEIGHT])
262 return -EINVAL;
263
264 required_mem_len = var->xres * var->yres * xenfb_info->page->depth / 8;
265 if (var->bits_per_pixel == xenfb_info->page->depth &&
266 var->xres <= info->fix.line_length / (XENFB_DEPTH / 8) &&
267 required_mem_len <= info->fix.smem_len) {
268 var->xres_virtual = var->xres;
269 var->yres_virtual = var->yres;
270 return 0;
271 }
272 return -EINVAL;
273 }
274
xenfb_set_par(struct fb_info * info)275 static int xenfb_set_par(struct fb_info *info)
276 {
277 struct xenfb_info *xenfb_info;
278 unsigned long flags;
279
280 xenfb_info = info->par;
281
282 spin_lock_irqsave(&xenfb_info->resize_lock, flags);
283 xenfb_info->resize.type = XENFB_TYPE_RESIZE;
284 xenfb_info->resize.width = info->var.xres;
285 xenfb_info->resize.height = info->var.yres;
286 xenfb_info->resize.stride = info->fix.line_length;
287 xenfb_info->resize.depth = info->var.bits_per_pixel;
288 xenfb_info->resize.offset = 0;
289 xenfb_info->resize_dpy = 1;
290 spin_unlock_irqrestore(&xenfb_info->resize_lock, flags);
291 return 0;
292 }
293
xenfb_defio_damage_range(struct fb_info * info,off_t off,size_t len)294 static void xenfb_defio_damage_range(struct fb_info *info, off_t off, size_t len)
295 {
296 struct xenfb_info *xenfb_info = info->par;
297
298 xenfb_refresh(xenfb_info, 0, 0, xenfb_info->page->width, xenfb_info->page->height);
299 }
300
xenfb_defio_damage_area(struct fb_info * info,u32 x,u32 y,u32 width,u32 height)301 static void xenfb_defio_damage_area(struct fb_info *info, u32 x, u32 y,
302 u32 width, u32 height)
303 {
304 struct xenfb_info *xenfb_info = info->par;
305
306 xenfb_refresh(xenfb_info, x, y, width, height);
307 }
308
309 FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(xenfb,
310 xenfb_defio_damage_range,
311 xenfb_defio_damage_area)
312
313 static const struct fb_ops xenfb_fb_ops = {
314 .owner = THIS_MODULE,
315 FB_DEFAULT_DEFERRED_OPS(xenfb),
316 .fb_setcolreg = xenfb_setcolreg,
317 .fb_check_var = xenfb_check_var,
318 .fb_set_par = xenfb_set_par,
319 };
320
xenfb_event_handler(int rq,void * dev_id)321 static irqreturn_t xenfb_event_handler(int rq, void *dev_id)
322 {
323 /*
324 * No in events recognized, simply ignore them all.
325 * If you need to recognize some, see xen-kbdfront's
326 * input_handler() for how to do that.
327 */
328 struct xenfb_info *info = dev_id;
329 struct xenfb_page *page = info->page;
330
331 if (page->in_cons != page->in_prod) {
332 info->page->in_cons = info->page->in_prod;
333 notify_remote_via_irq(info->irq);
334 }
335
336 /* Flush dirty rectangle: */
337 xenfb_refresh(info, INT_MAX, INT_MAX, -INT_MAX, -INT_MAX);
338
339 return IRQ_HANDLED;
340 }
341
xenfb_probe(struct xenbus_device * dev,const struct xenbus_device_id * id)342 static int xenfb_probe(struct xenbus_device *dev,
343 const struct xenbus_device_id *id)
344 {
345 struct xenfb_info *info;
346 struct fb_info *fb_info;
347 int fb_size;
348 int val;
349 int ret = 0;
350
351 info = kzalloc(sizeof(*info), GFP_KERNEL);
352 if (info == NULL) {
353 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
354 return -ENOMEM;
355 }
356
357 /* Limit kernel param videoram amount to what is in xenstore */
358 if (xenbus_scanf(XBT_NIL, dev->otherend, "videoram", "%d", &val) == 1) {
359 if (val < video[KPARAM_MEM])
360 video[KPARAM_MEM] = val;
361 }
362
363 video[KPARAM_WIDTH] = xenbus_read_unsigned(dev->otherend, "width",
364 video[KPARAM_WIDTH]);
365 video[KPARAM_HEIGHT] = xenbus_read_unsigned(dev->otherend, "height",
366 video[KPARAM_HEIGHT]);
367
368 /* If requested res does not fit in available memory, use default */
369 fb_size = video[KPARAM_MEM] * 1024 * 1024;
370 if (video[KPARAM_WIDTH] * video[KPARAM_HEIGHT] * XENFB_DEPTH / 8
371 > fb_size) {
372 pr_warn("display parameters %d,%d,%d invalid, use defaults\n",
373 video[KPARAM_MEM], video[KPARAM_WIDTH],
374 video[KPARAM_HEIGHT]);
375 video[KPARAM_WIDTH] = XENFB_WIDTH;
376 video[KPARAM_HEIGHT] = XENFB_HEIGHT;
377 fb_size = XENFB_DEFAULT_FB_LEN;
378 }
379
380 dev_set_drvdata(&dev->dev, info);
381 info->xbdev = dev;
382 info->irq = -1;
383 info->x1 = info->y1 = INT_MAX;
384 spin_lock_init(&info->dirty_lock);
385 spin_lock_init(&info->resize_lock);
386
387 info->fb = vzalloc(fb_size);
388 if (info->fb == NULL)
389 goto error_nomem;
390
391 info->nr_pages = (fb_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
392
393 info->gfns = vmalloc(array_size(sizeof(unsigned long), info->nr_pages));
394 if (!info->gfns)
395 goto error_nomem;
396
397 /* set up shared page */
398 info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
399 if (!info->page)
400 goto error_nomem;
401
402 /* abusing framebuffer_alloc() to allocate pseudo_palette */
403 fb_info = framebuffer_alloc(sizeof(u32) * 256, NULL);
404 if (fb_info == NULL)
405 goto error_nomem;
406
407 /* complete the abuse: */
408 fb_info->pseudo_palette = fb_info->par;
409 fb_info->par = info;
410
411 fb_info->screen_buffer = info->fb;
412
413 fb_info->fbops = &xenfb_fb_ops;
414 fb_info->var.xres_virtual = fb_info->var.xres = video[KPARAM_WIDTH];
415 fb_info->var.yres_virtual = fb_info->var.yres = video[KPARAM_HEIGHT];
416 fb_info->var.bits_per_pixel = XENFB_DEPTH;
417
418 fb_info->var.red = (struct fb_bitfield){16, 8, 0};
419 fb_info->var.green = (struct fb_bitfield){8, 8, 0};
420 fb_info->var.blue = (struct fb_bitfield){0, 8, 0};
421
422 fb_info->var.activate = FB_ACTIVATE_NOW;
423 fb_info->var.height = -1;
424 fb_info->var.width = -1;
425 fb_info->var.vmode = FB_VMODE_NONINTERLACED;
426
427 fb_info->fix.visual = FB_VISUAL_TRUECOLOR;
428 fb_info->fix.line_length = fb_info->var.xres * XENFB_DEPTH / 8;
429 fb_info->fix.smem_start = 0;
430 fb_info->fix.smem_len = fb_size;
431 strcpy(fb_info->fix.id, "xen");
432 fb_info->fix.type = FB_TYPE_PACKED_PIXELS;
433 fb_info->fix.accel = FB_ACCEL_NONE;
434
435 fb_info->flags = FBINFO_VIRTFB;
436
437 ret = fb_alloc_cmap(&fb_info->cmap, 256, 0);
438 if (ret < 0) {
439 framebuffer_release(fb_info);
440 xenbus_dev_fatal(dev, ret, "fb_alloc_cmap");
441 goto error;
442 }
443
444 fb_info->fbdefio = &xenfb_defio;
445 fb_deferred_io_init(fb_info);
446
447 xenfb_init_shared_page(info, fb_info);
448
449 ret = xenfb_connect_backend(dev, info);
450 if (ret < 0) {
451 xenbus_dev_fatal(dev, ret, "xenfb_connect_backend");
452 goto error_fb;
453 }
454
455 ret = register_framebuffer(fb_info);
456 if (ret) {
457 xenbus_dev_fatal(dev, ret, "register_framebuffer");
458 goto error_fb;
459 }
460 info->fb_info = fb_info;
461
462 xenfb_make_preferred_console();
463 return 0;
464
465 error_fb:
466 fb_deferred_io_cleanup(fb_info);
467 fb_dealloc_cmap(&fb_info->cmap);
468 framebuffer_release(fb_info);
469 error_nomem:
470 if (!ret) {
471 ret = -ENOMEM;
472 xenbus_dev_fatal(dev, ret, "allocating device memory");
473 }
474 error:
475 xenfb_remove(dev);
476 return ret;
477 }
478
xenfb_make_preferred_console(void)479 static void xenfb_make_preferred_console(void)
480 {
481 struct console *c;
482
483 if (console_set_on_cmdline)
484 return;
485
486 console_list_lock();
487 for_each_console(c) {
488 if (!strcmp(c->name, "tty") && c->index == 0)
489 break;
490 }
491 if (c)
492 console_force_preferred_locked(c);
493 console_list_unlock();
494 }
495
xenfb_resume(struct xenbus_device * dev)496 static int xenfb_resume(struct xenbus_device *dev)
497 {
498 struct xenfb_info *info = dev_get_drvdata(&dev->dev);
499
500 xenfb_disconnect_backend(info);
501 xenfb_init_shared_page(info, info->fb_info);
502 return xenfb_connect_backend(dev, info);
503 }
504
xenfb_remove(struct xenbus_device * dev)505 static void xenfb_remove(struct xenbus_device *dev)
506 {
507 struct xenfb_info *info = dev_get_drvdata(&dev->dev);
508
509 xenfb_disconnect_backend(info);
510 if (info->fb_info) {
511 fb_deferred_io_cleanup(info->fb_info);
512 unregister_framebuffer(info->fb_info);
513 fb_dealloc_cmap(&info->fb_info->cmap);
514 framebuffer_release(info->fb_info);
515 }
516 free_page((unsigned long)info->page);
517 vfree(info->gfns);
518 vfree(info->fb);
519 kfree(info);
520 }
521
vmalloc_to_gfn(void * address)522 static unsigned long vmalloc_to_gfn(void *address)
523 {
524 return xen_page_to_gfn(vmalloc_to_page(address));
525 }
526
xenfb_init_shared_page(struct xenfb_info * info,struct fb_info * fb_info)527 static void xenfb_init_shared_page(struct xenfb_info *info,
528 struct fb_info *fb_info)
529 {
530 int i;
531 int epd = PAGE_SIZE / sizeof(info->gfns[0]);
532
533 for (i = 0; i < info->nr_pages; i++)
534 info->gfns[i] = vmalloc_to_gfn(info->fb + i * PAGE_SIZE);
535
536 for (i = 0; i * epd < info->nr_pages; i++)
537 info->page->pd[i] = vmalloc_to_gfn(&info->gfns[i * epd]);
538
539 info->page->width = fb_info->var.xres;
540 info->page->height = fb_info->var.yres;
541 info->page->depth = fb_info->var.bits_per_pixel;
542 info->page->line_length = fb_info->fix.line_length;
543 info->page->mem_length = fb_info->fix.smem_len;
544 info->page->in_cons = info->page->in_prod = 0;
545 info->page->out_cons = info->page->out_prod = 0;
546 }
547
xenfb_connect_backend(struct xenbus_device * dev,struct xenfb_info * info)548 static int xenfb_connect_backend(struct xenbus_device *dev,
549 struct xenfb_info *info)
550 {
551 int ret, evtchn, irq;
552 struct xenbus_transaction xbt;
553
554 ret = xenbus_alloc_evtchn(dev, &evtchn);
555 if (ret)
556 return ret;
557 irq = bind_evtchn_to_irqhandler(evtchn, xenfb_event_handler,
558 0, dev->devicetype, info);
559 if (irq < 0) {
560 xenbus_free_evtchn(dev, evtchn);
561 xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
562 return irq;
563 }
564 again:
565 ret = xenbus_transaction_start(&xbt);
566 if (ret) {
567 xenbus_dev_fatal(dev, ret, "starting transaction");
568 goto unbind_irq;
569 }
570 ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
571 virt_to_gfn(info->page));
572 if (ret)
573 goto error_xenbus;
574 ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
575 evtchn);
576 if (ret)
577 goto error_xenbus;
578 ret = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
579 XEN_IO_PROTO_ABI_NATIVE);
580 if (ret)
581 goto error_xenbus;
582 ret = xenbus_printf(xbt, dev->nodename, "feature-update", "1");
583 if (ret)
584 goto error_xenbus;
585 ret = xenbus_transaction_end(xbt, 0);
586 if (ret) {
587 if (ret == -EAGAIN)
588 goto again;
589 xenbus_dev_fatal(dev, ret, "completing transaction");
590 goto unbind_irq;
591 }
592
593 xenbus_switch_state(dev, XenbusStateInitialised);
594 info->irq = irq;
595 return 0;
596
597 error_xenbus:
598 xenbus_transaction_end(xbt, 1);
599 xenbus_dev_fatal(dev, ret, "writing xenstore");
600 unbind_irq:
601 unbind_from_irqhandler(irq, info);
602 return ret;
603 }
604
xenfb_disconnect_backend(struct xenfb_info * info)605 static void xenfb_disconnect_backend(struct xenfb_info *info)
606 {
607 /* Prevent xenfb refresh */
608 info->update_wanted = 0;
609 if (info->irq >= 0)
610 unbind_from_irqhandler(info->irq, info);
611 info->irq = -1;
612 }
613
xenfb_backend_changed(struct xenbus_device * dev,enum xenbus_state backend_state)614 static void xenfb_backend_changed(struct xenbus_device *dev,
615 enum xenbus_state backend_state)
616 {
617 struct xenfb_info *info = dev_get_drvdata(&dev->dev);
618
619 switch (backend_state) {
620 case XenbusStateInitialising:
621 case XenbusStateInitialised:
622 case XenbusStateReconfiguring:
623 case XenbusStateReconfigured:
624 case XenbusStateUnknown:
625 break;
626
627 case XenbusStateInitWait:
628 xenbus_switch_state(dev, XenbusStateConnected);
629 break;
630
631 case XenbusStateConnected:
632 /*
633 * Work around xenbus race condition: If backend goes
634 * through InitWait to Connected fast enough, we can
635 * get Connected twice here.
636 */
637 if (dev->state != XenbusStateConnected)
638 /* no InitWait seen yet, fudge it */
639 xenbus_switch_state(dev, XenbusStateConnected);
640
641 if (xenbus_read_unsigned(info->xbdev->otherend,
642 "request-update", 0))
643 info->update_wanted = 1;
644
645 info->feature_resize = xenbus_read_unsigned(dev->otherend,
646 "feature-resize", 0);
647 break;
648
649 case XenbusStateClosed:
650 if (dev->state == XenbusStateClosed)
651 break;
652 fallthrough; /* Missed the backend's CLOSING state */
653 case XenbusStateClosing:
654 xenbus_frontend_closed(dev);
655 break;
656 }
657 }
658
659 static const struct xenbus_device_id xenfb_ids[] = {
660 { "vfb" },
661 { "" }
662 };
663
664 static struct xenbus_driver xenfb_driver = {
665 .ids = xenfb_ids,
666 .probe = xenfb_probe,
667 .remove = xenfb_remove,
668 .resume = xenfb_resume,
669 .otherend_changed = xenfb_backend_changed,
670 .not_essential = true,
671 };
672
xenfb_init(void)673 static int __init xenfb_init(void)
674 {
675 if (!xen_domain())
676 return -ENODEV;
677
678 /* Nothing to do if running in dom0. */
679 if (xen_initial_domain())
680 return -ENODEV;
681
682 if (!xen_has_pv_devices())
683 return -ENODEV;
684
685 return xenbus_register_frontend(&xenfb_driver);
686 }
687
xenfb_cleanup(void)688 static void __exit xenfb_cleanup(void)
689 {
690 xenbus_unregister_driver(&xenfb_driver);
691 }
692
693 module_init(xenfb_init);
694 module_exit(xenfb_cleanup);
695
696 MODULE_DESCRIPTION("Xen virtual framebuffer device frontend");
697 MODULE_LICENSE("GPL");
698 MODULE_ALIAS("xen:vfb");
699