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