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 fb_info->device = &dev->dev;
411
412 fb_info->screen_buffer = info->fb;
413
414 fb_info->fbops = &xenfb_fb_ops;
415 fb_info->var.xres_virtual = fb_info->var.xres = video[KPARAM_WIDTH];
416 fb_info->var.yres_virtual = fb_info->var.yres = video[KPARAM_HEIGHT];
417 fb_info->var.bits_per_pixel = XENFB_DEPTH;
418
419 fb_info->var.red = (struct fb_bitfield){16, 8, 0};
420 fb_info->var.green = (struct fb_bitfield){8, 8, 0};
421 fb_info->var.blue = (struct fb_bitfield){0, 8, 0};
422
423 fb_info->var.activate = FB_ACTIVATE_NOW;
424 fb_info->var.height = -1;
425 fb_info->var.width = -1;
426 fb_info->var.vmode = FB_VMODE_NONINTERLACED;
427
428 fb_info->fix.visual = FB_VISUAL_TRUECOLOR;
429 fb_info->fix.line_length = fb_info->var.xres * XENFB_DEPTH / 8;
430 fb_info->fix.smem_start = 0;
431 fb_info->fix.smem_len = fb_size;
432 strcpy(fb_info->fix.id, "xen");
433 fb_info->fix.type = FB_TYPE_PACKED_PIXELS;
434 fb_info->fix.accel = FB_ACCEL_NONE;
435
436 fb_info->flags = FBINFO_VIRTFB;
437
438 ret = fb_alloc_cmap(&fb_info->cmap, 256, 0);
439 if (ret < 0) {
440 framebuffer_release(fb_info);
441 xenbus_dev_fatal(dev, ret, "fb_alloc_cmap");
442 goto error;
443 }
444
445 fb_info->fbdefio = &xenfb_defio;
446 fb_deferred_io_init(fb_info);
447
448 xenfb_init_shared_page(info, fb_info);
449
450 ret = xenfb_connect_backend(dev, info);
451 if (ret < 0) {
452 xenbus_dev_fatal(dev, ret, "xenfb_connect_backend");
453 goto error_fb;
454 }
455
456 ret = register_framebuffer(fb_info);
457 if (ret) {
458 xenbus_dev_fatal(dev, ret, "register_framebuffer");
459 goto error_fb;
460 }
461 info->fb_info = fb_info;
462
463 xenfb_make_preferred_console();
464 return 0;
465
466 error_fb:
467 fb_deferred_io_cleanup(fb_info);
468 fb_dealloc_cmap(&fb_info->cmap);
469 framebuffer_release(fb_info);
470 error_nomem:
471 if (!ret) {
472 ret = -ENOMEM;
473 xenbus_dev_fatal(dev, ret, "allocating device memory");
474 }
475 error:
476 xenfb_remove(dev);
477 return ret;
478 }
479
xenfb_make_preferred_console(void)480 static void xenfb_make_preferred_console(void)
481 {
482 struct console *c;
483
484 if (console_set_on_cmdline)
485 return;
486
487 console_list_lock();
488 for_each_console(c) {
489 if (!strcmp(c->name, "tty") && c->index == 0)
490 break;
491 }
492 if (c)
493 console_force_preferred_locked(c);
494 console_list_unlock();
495 }
496
xenfb_resume(struct xenbus_device * dev)497 static int xenfb_resume(struct xenbus_device *dev)
498 {
499 struct xenfb_info *info = dev_get_drvdata(&dev->dev);
500
501 xenfb_disconnect_backend(info);
502 xenfb_init_shared_page(info, info->fb_info);
503 return xenfb_connect_backend(dev, info);
504 }
505
xenfb_remove(struct xenbus_device * dev)506 static void xenfb_remove(struct xenbus_device *dev)
507 {
508 struct xenfb_info *info = dev_get_drvdata(&dev->dev);
509
510 xenfb_disconnect_backend(info);
511 if (info->fb_info) {
512 fb_deferred_io_cleanup(info->fb_info);
513 unregister_framebuffer(info->fb_info);
514 fb_dealloc_cmap(&info->fb_info->cmap);
515 framebuffer_release(info->fb_info);
516 }
517 free_page((unsigned long)info->page);
518 vfree(info->gfns);
519 vfree(info->fb);
520 kfree(info);
521 }
522
vmalloc_to_gfn(void * address)523 static unsigned long vmalloc_to_gfn(void *address)
524 {
525 return xen_page_to_gfn(vmalloc_to_page(address));
526 }
527
xenfb_init_shared_page(struct xenfb_info * info,struct fb_info * fb_info)528 static void xenfb_init_shared_page(struct xenfb_info *info,
529 struct fb_info *fb_info)
530 {
531 int i;
532 int epd = PAGE_SIZE / sizeof(info->gfns[0]);
533
534 for (i = 0; i < info->nr_pages; i++)
535 info->gfns[i] = vmalloc_to_gfn(info->fb + i * PAGE_SIZE);
536
537 for (i = 0; i * epd < info->nr_pages; i++)
538 info->page->pd[i] = vmalloc_to_gfn(&info->gfns[i * epd]);
539
540 info->page->width = fb_info->var.xres;
541 info->page->height = fb_info->var.yres;
542 info->page->depth = fb_info->var.bits_per_pixel;
543 info->page->line_length = fb_info->fix.line_length;
544 info->page->mem_length = fb_info->fix.smem_len;
545 info->page->in_cons = info->page->in_prod = 0;
546 info->page->out_cons = info->page->out_prod = 0;
547 }
548
xenfb_connect_backend(struct xenbus_device * dev,struct xenfb_info * info)549 static int xenfb_connect_backend(struct xenbus_device *dev,
550 struct xenfb_info *info)
551 {
552 int ret, evtchn, irq;
553 struct xenbus_transaction xbt;
554
555 ret = xenbus_alloc_evtchn(dev, &evtchn);
556 if (ret)
557 return ret;
558 irq = bind_evtchn_to_irqhandler(evtchn, xenfb_event_handler,
559 0, dev->devicetype, info);
560 if (irq < 0) {
561 xenbus_free_evtchn(dev, evtchn);
562 xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
563 return irq;
564 }
565 again:
566 ret = xenbus_transaction_start(&xbt);
567 if (ret) {
568 xenbus_dev_fatal(dev, ret, "starting transaction");
569 goto unbind_irq;
570 }
571 ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
572 virt_to_gfn(info->page));
573 if (ret)
574 goto error_xenbus;
575 ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
576 evtchn);
577 if (ret)
578 goto error_xenbus;
579 ret = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
580 XEN_IO_PROTO_ABI_NATIVE);
581 if (ret)
582 goto error_xenbus;
583 ret = xenbus_printf(xbt, dev->nodename, "feature-update", "1");
584 if (ret)
585 goto error_xenbus;
586 ret = xenbus_transaction_end(xbt, 0);
587 if (ret) {
588 if (ret == -EAGAIN)
589 goto again;
590 xenbus_dev_fatal(dev, ret, "completing transaction");
591 goto unbind_irq;
592 }
593
594 xenbus_switch_state(dev, XenbusStateInitialised);
595 info->irq = irq;
596 return 0;
597
598 error_xenbus:
599 xenbus_transaction_end(xbt, 1);
600 xenbus_dev_fatal(dev, ret, "writing xenstore");
601 unbind_irq:
602 unbind_from_irqhandler(irq, info);
603 return ret;
604 }
605
xenfb_disconnect_backend(struct xenfb_info * info)606 static void xenfb_disconnect_backend(struct xenfb_info *info)
607 {
608 /* Prevent xenfb refresh */
609 info->update_wanted = 0;
610 if (info->irq >= 0)
611 unbind_from_irqhandler(info->irq, info);
612 info->irq = -1;
613 }
614
xenfb_backend_changed(struct xenbus_device * dev,enum xenbus_state backend_state)615 static void xenfb_backend_changed(struct xenbus_device *dev,
616 enum xenbus_state backend_state)
617 {
618 struct xenfb_info *info = dev_get_drvdata(&dev->dev);
619
620 switch (backend_state) {
621 case XenbusStateInitialising:
622 case XenbusStateInitialised:
623 case XenbusStateReconfiguring:
624 case XenbusStateReconfigured:
625 case XenbusStateUnknown:
626 break;
627
628 case XenbusStateInitWait:
629 xenbus_switch_state(dev, XenbusStateConnected);
630 break;
631
632 case XenbusStateConnected:
633 /*
634 * Work around xenbus race condition: If backend goes
635 * through InitWait to Connected fast enough, we can
636 * get Connected twice here.
637 */
638 if (dev->state != XenbusStateConnected)
639 /* no InitWait seen yet, fudge it */
640 xenbus_switch_state(dev, XenbusStateConnected);
641
642 if (xenbus_read_unsigned(info->xbdev->otherend,
643 "request-update", 0))
644 info->update_wanted = 1;
645
646 info->feature_resize = xenbus_read_unsigned(dev->otherend,
647 "feature-resize", 0);
648 break;
649
650 case XenbusStateClosed:
651 if (dev->state == XenbusStateClosed)
652 break;
653 fallthrough; /* Missed the backend's CLOSING state */
654 case XenbusStateClosing:
655 xenbus_frontend_closed(dev);
656 break;
657 }
658 }
659
660 static const struct xenbus_device_id xenfb_ids[] = {
661 { "vfb" },
662 { "" }
663 };
664
665 static struct xenbus_driver xenfb_driver = {
666 .ids = xenfb_ids,
667 .probe = xenfb_probe,
668 .remove = xenfb_remove,
669 .resume = xenfb_resume,
670 .otherend_changed = xenfb_backend_changed,
671 .not_essential = true,
672 };
673
xenfb_init(void)674 static int __init xenfb_init(void)
675 {
676 if (!xen_domain())
677 return -ENODEV;
678
679 /* Nothing to do if running in dom0. */
680 if (xen_initial_domain())
681 return -ENODEV;
682
683 if (!xen_has_pv_devices())
684 return -ENODEV;
685
686 return xenbus_register_frontend(&xenfb_driver);
687 }
688
xenfb_cleanup(void)689 static void __exit xenfb_cleanup(void)
690 {
691 xenbus_unregister_driver(&xenfb_driver);
692 }
693
694 module_init(xenfb_init);
695 module_exit(xenfb_cleanup);
696
697 MODULE_DESCRIPTION("Xen virtual framebuffer device frontend");
698 MODULE_LICENSE("GPL");
699 MODULE_ALIAS("xen:vfb");
700