xen-fbfront.c revision 1ccbf5344c3daef046d2323190cc6807c44f1917 
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/vmalloc.h>
27#include <linux/mm.h>
28
29#include <asm/xen/hypervisor.h>
30
31#include <xen/xen.h>
32#include <xen/events.h>
33#include <xen/page.h>
34#include <xen/interface/io/fbif.h>
35#include <xen/interface/io/protocols.h>
36#include <xen/xenbus.h>
37
38struct xenfb_info {
39	unsigned char		*fb;
40	struct fb_info		*fb_info;
41	int			x1, y1, x2, y2;	/* dirty rectangle,
42						   protected by dirty_lock */
43	spinlock_t		dirty_lock;
44	int			nr_pages;
45	int			irq;
46	struct xenfb_page	*page;
47	unsigned long 		*mfns;
48	int			update_wanted; /* XENFB_TYPE_UPDATE wanted */
49	int			feature_resize; /* XENFB_TYPE_RESIZE ok */
50	struct xenfb_resize	resize;		/* protected by resize_lock */
51	int			resize_dpy;	/* ditto */
52	spinlock_t		resize_lock;
53
54	struct xenbus_device	*xbdev;
55};
56
57#define XENFB_DEFAULT_FB_LEN (XENFB_WIDTH * XENFB_HEIGHT * XENFB_DEPTH / 8)
58
59enum { KPARAM_MEM, KPARAM_WIDTH, KPARAM_HEIGHT, KPARAM_CNT };
60static int video[KPARAM_CNT] = { 2, XENFB_WIDTH, XENFB_HEIGHT };
61module_param_array(video, int, NULL, 0);
62MODULE_PARM_DESC(video,
63	"Video memory size in MB, width, height in pixels (default 2,800,600)");
64
65static void xenfb_make_preferred_console(void);
66static int xenfb_remove(struct xenbus_device *);
67static void xenfb_init_shared_page(struct xenfb_info *, struct fb_info *);
68static int xenfb_connect_backend(struct xenbus_device *, struct xenfb_info *);
69static void xenfb_disconnect_backend(struct xenfb_info *);
70
71static void xenfb_send_event(struct xenfb_info *info,
72			     union xenfb_out_event *event)
73{
74	u32 prod;
75
76	prod = info->page->out_prod;
77	/* caller ensures !xenfb_queue_full() */
78	mb();			/* ensure ring space available */
79	XENFB_OUT_RING_REF(info->page, prod) = *event;
80	wmb();			/* ensure ring contents visible */
81	info->page->out_prod = prod + 1;
82
83	notify_remote_via_irq(info->irq);
84}
85
86static void xenfb_do_update(struct xenfb_info *info,
87			    int x, int y, int w, int h)
88{
89	union xenfb_out_event event;
90
91	memset(&event, 0, sizeof(event));
92	event.type = XENFB_TYPE_UPDATE;
93	event.update.x = x;
94	event.update.y = y;
95	event.update.width = w;
96	event.update.height = h;
97
98	/* caller ensures !xenfb_queue_full() */
99	xenfb_send_event(info, &event);
100}
101
102static void xenfb_do_resize(struct xenfb_info *info)
103{
104	union xenfb_out_event event;
105
106	memset(&event, 0, sizeof(event));
107	event.resize = info->resize;
108
109	/* caller ensures !xenfb_queue_full() */
110	xenfb_send_event(info, &event);
111}
112
113static int xenfb_queue_full(struct xenfb_info *info)
114{
115	u32 cons, prod;
116
117	prod = info->page->out_prod;
118	cons = info->page->out_cons;
119	return prod - cons == XENFB_OUT_RING_LEN;
120}
121
122static void xenfb_handle_resize_dpy(struct xenfb_info *info)
123{
124	unsigned long flags;
125
126	spin_lock_irqsave(&info->resize_lock, flags);
127	if (info->resize_dpy) {
128		if (!xenfb_queue_full(info)) {
129			info->resize_dpy = 0;
130			xenfb_do_resize(info);
131		}
132	}
133	spin_unlock_irqrestore(&info->resize_lock, flags);
134}
135
136static void xenfb_refresh(struct xenfb_info *info,
137			  int x1, int y1, int w, int h)
138{
139	unsigned long flags;
140	int x2 = x1 + w - 1;
141	int y2 = y1 + h - 1;
142
143	xenfb_handle_resize_dpy(info);
144
145	if (!info->update_wanted)
146		return;
147
148	spin_lock_irqsave(&info->dirty_lock, flags);
149
150	/* Combine with dirty rectangle: */
151	if (info->y1 < y1)
152		y1 = info->y1;
153	if (info->y2 > y2)
154		y2 = info->y2;
155	if (info->x1 < x1)
156		x1 = info->x1;
157	if (info->x2 > x2)
158		x2 = info->x2;
159
160	if (xenfb_queue_full(info)) {
161		/* Can't send right now, stash it in the dirty rectangle */
162		info->x1 = x1;
163		info->x2 = x2;
164		info->y1 = y1;
165		info->y2 = y2;
166		spin_unlock_irqrestore(&info->dirty_lock, flags);
167		return;
168	}
169
170	/* Clear dirty rectangle: */
171	info->x1 = info->y1 = INT_MAX;
172	info->x2 = info->y2 = 0;
173
174	spin_unlock_irqrestore(&info->dirty_lock, flags);
175
176	if (x1 <= x2 && y1 <= y2)
177		xenfb_do_update(info, x1, y1, x2 - x1 + 1, y2 - y1 + 1);
178}
179
180static void xenfb_deferred_io(struct fb_info *fb_info,
181			      struct list_head *pagelist)
182{
183	struct xenfb_info *info = fb_info->par;
184	struct page *page;
185	unsigned long beg, end;
186	int y1, y2, miny, maxy;
187
188	miny = INT_MAX;
189	maxy = 0;
190	list_for_each_entry(page, pagelist, lru) {
191		beg = page->index << PAGE_SHIFT;
192		end = beg + PAGE_SIZE - 1;
193		y1 = beg / fb_info->fix.line_length;
194		y2 = end / fb_info->fix.line_length;
195		if (y2 >= fb_info->var.yres)
196			y2 = fb_info->var.yres - 1;
197		if (miny > y1)
198			miny = y1;
199		if (maxy < y2)
200			maxy = y2;
201	}
202	xenfb_refresh(info, 0, miny, fb_info->var.xres, maxy - miny + 1);
203}
204
205static struct fb_deferred_io xenfb_defio = {
206	.delay		= HZ / 20,
207	.deferred_io	= xenfb_deferred_io,
208};
209
210static int xenfb_setcolreg(unsigned regno, unsigned red, unsigned green,
211			   unsigned blue, unsigned transp,
212			   struct fb_info *info)
213{
214	u32 v;
215
216	if (regno > info->cmap.len)
217		return 1;
218
219#define CNVT_TOHW(val, width) ((((val)<<(width))+0x7FFF-(val))>>16)
220	red = CNVT_TOHW(red, info->var.red.length);
221	green = CNVT_TOHW(green, info->var.green.length);
222	blue = CNVT_TOHW(blue, info->var.blue.length);
223	transp = CNVT_TOHW(transp, info->var.transp.length);
224#undef CNVT_TOHW
225
226	v = (red << info->var.red.offset) |
227	    (green << info->var.green.offset) |
228	    (blue << info->var.blue.offset);
229
230	switch (info->var.bits_per_pixel) {
231	case 16:
232	case 24:
233	case 32:
234		((u32 *)info->pseudo_palette)[regno] = v;
235		break;
236	}
237
238	return 0;
239}
240
241static void xenfb_fillrect(struct fb_info *p, const struct fb_fillrect *rect)
242{
243	struct xenfb_info *info = p->par;
244
245	sys_fillrect(p, rect);
246	xenfb_refresh(info, rect->dx, rect->dy, rect->width, rect->height);
247}
248
249static void xenfb_imageblit(struct fb_info *p, const struct fb_image *image)
250{
251	struct xenfb_info *info = p->par;
252
253	sys_imageblit(p, image);
254	xenfb_refresh(info, image->dx, image->dy, image->width, image->height);
255}
256
257static void xenfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
258{
259	struct xenfb_info *info = p->par;
260
261	sys_copyarea(p, area);
262	xenfb_refresh(info, area->dx, area->dy, area->width, area->height);
263}
264
265static ssize_t xenfb_write(struct fb_info *p, const char __user *buf,
266			size_t count, loff_t *ppos)
267{
268	struct xenfb_info *info = p->par;
269	ssize_t res;
270
271	res = fb_sys_write(p, buf, count, ppos);
272	xenfb_refresh(info, 0, 0, info->page->width, info->page->height);
273	return res;
274}
275
276static int
277xenfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
278{
279	struct xenfb_info *xenfb_info;
280	int required_mem_len;
281
282	xenfb_info = info->par;
283
284	if (!xenfb_info->feature_resize) {
285		if (var->xres == video[KPARAM_WIDTH] &&
286		    var->yres == video[KPARAM_HEIGHT] &&
287		    var->bits_per_pixel == xenfb_info->page->depth) {
288			return 0;
289		}
290		return -EINVAL;
291	}
292
293	/* Can't resize past initial width and height */
294	if (var->xres > video[KPARAM_WIDTH] || var->yres > video[KPARAM_HEIGHT])
295		return -EINVAL;
296
297	required_mem_len = var->xres * var->yres * xenfb_info->page->depth / 8;
298	if (var->bits_per_pixel == xenfb_info->page->depth &&
299	    var->xres <= info->fix.line_length / (XENFB_DEPTH / 8) &&
300	    required_mem_len <= info->fix.smem_len) {
301		var->xres_virtual = var->xres;
302		var->yres_virtual = var->yres;
303		return 0;
304	}
305	return -EINVAL;
306}
307
308static int xenfb_set_par(struct fb_info *info)
309{
310	struct xenfb_info *xenfb_info;
311	unsigned long flags;
312
313	xenfb_info = info->par;
314
315	spin_lock_irqsave(&xenfb_info->resize_lock, flags);
316	xenfb_info->resize.type = XENFB_TYPE_RESIZE;
317	xenfb_info->resize.width = info->var.xres;
318	xenfb_info->resize.height = info->var.yres;
319	xenfb_info->resize.stride = info->fix.line_length;
320	xenfb_info->resize.depth = info->var.bits_per_pixel;
321	xenfb_info->resize.offset = 0;
322	xenfb_info->resize_dpy = 1;
323	spin_unlock_irqrestore(&xenfb_info->resize_lock, flags);
324	return 0;
325}
326
327static struct fb_ops xenfb_fb_ops = {
328	.owner		= THIS_MODULE,
329	.fb_read	= fb_sys_read,
330	.fb_write	= xenfb_write,
331	.fb_setcolreg	= xenfb_setcolreg,
332	.fb_fillrect	= xenfb_fillrect,
333	.fb_copyarea	= xenfb_copyarea,
334	.fb_imageblit	= xenfb_imageblit,
335	.fb_check_var	= xenfb_check_var,
336	.fb_set_par     = xenfb_set_par,
337};
338
339static irqreturn_t xenfb_event_handler(int rq, void *dev_id)
340{
341	/*
342	 * No in events recognized, simply ignore them all.
343	 * If you need to recognize some, see xen-kbdfront's
344	 * input_handler() for how to do that.
345	 */
346	struct xenfb_info *info = dev_id;
347	struct xenfb_page *page = info->page;
348
349	if (page->in_cons != page->in_prod) {
350		info->page->in_cons = info->page->in_prod;
351		notify_remote_via_irq(info->irq);
352	}
353
354	/* Flush dirty rectangle: */
355	xenfb_refresh(info, INT_MAX, INT_MAX, -INT_MAX, -INT_MAX);
356
357	return IRQ_HANDLED;
358}
359
360static int __devinit xenfb_probe(struct xenbus_device *dev,
361				 const struct xenbus_device_id *id)
362{
363	struct xenfb_info *info;
364	struct fb_info *fb_info;
365	int fb_size;
366	int val;
367	int ret;
368
369	info = kzalloc(sizeof(*info), GFP_KERNEL);
370	if (info == NULL) {
371		xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
372		return -ENOMEM;
373	}
374
375	/* Limit kernel param videoram amount to what is in xenstore */
376	if (xenbus_scanf(XBT_NIL, dev->otherend, "videoram", "%d", &val) == 1) {
377		if (val < video[KPARAM_MEM])
378			video[KPARAM_MEM] = val;
379	}
380
381	/* If requested res does not fit in available memory, use default */
382	fb_size = video[KPARAM_MEM] * 1024 * 1024;
383	if (video[KPARAM_WIDTH] * video[KPARAM_HEIGHT] * XENFB_DEPTH / 8
384	    > fb_size) {
385		video[KPARAM_WIDTH] = XENFB_WIDTH;
386		video[KPARAM_HEIGHT] = XENFB_HEIGHT;
387		fb_size = XENFB_DEFAULT_FB_LEN;
388	}
389
390	dev_set_drvdata(&dev->dev, info);
391	info->xbdev = dev;
392	info->irq = -1;
393	info->x1 = info->y1 = INT_MAX;
394	spin_lock_init(&info->dirty_lock);
395	spin_lock_init(&info->resize_lock);
396
397	info->fb = vmalloc(fb_size);
398	if (info->fb == NULL)
399		goto error_nomem;
400	memset(info->fb, 0, fb_size);
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;
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
485static __devinit void
486xenfb_make_preferred_console(void)
487{
488	struct console *c;
489
490	if (console_set_on_cmdline)
491		return;
492
493	acquire_console_sem();
494	for (c = console_drivers; c; c = c->next) {
495		if (!strcmp(c->name, "tty") && c->index == 0)
496			break;
497	}
498	release_console_sem();
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
507static 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
516static 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
535static unsigned long vmalloc_to_mfn(void *address)
536{
537	return pfn_to_mfn(vmalloc_to_pfn(address));
538}
539
540static 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
561static int xenfb_connect_backend(struct xenbus_device *dev,
562				 struct xenfb_info *info)
563{
564	int ret, evtchn;
565	struct xenbus_transaction xbt;
566
567	ret = xenbus_alloc_evtchn(dev, &evtchn);
568	if (ret)
569		return ret;
570	ret = bind_evtchn_to_irqhandler(evtchn, xenfb_event_handler,
571					0, dev->devicetype, info);
572	if (ret < 0) {
573		xenbus_free_evtchn(dev, evtchn);
574		xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
575		return ret;
576	}
577	info->irq = ret;
578
579 again:
580	ret = xenbus_transaction_start(&xbt);
581	if (ret) {
582		xenbus_dev_fatal(dev, ret, "starting transaction");
583		return ret;
584	}
585	ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
586			    virt_to_mfn(info->page));
587	if (ret)
588		goto error_xenbus;
589	ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
590			    evtchn);
591	if (ret)
592		goto error_xenbus;
593	ret = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
594			    XEN_IO_PROTO_ABI_NATIVE);
595	if (ret)
596		goto error_xenbus;
597	ret = xenbus_printf(xbt, dev->nodename, "feature-update", "1");
598	if (ret)
599		goto error_xenbus;
600	ret = xenbus_transaction_end(xbt, 0);
601	if (ret) {
602		if (ret == -EAGAIN)
603			goto again;
604		xenbus_dev_fatal(dev, ret, "completing transaction");
605		return ret;
606	}
607
608	xenbus_switch_state(dev, XenbusStateInitialised);
609	return 0;
610
611 error_xenbus:
612	xenbus_transaction_end(xbt, 1);
613	xenbus_dev_fatal(dev, ret, "writing xenstore");
614	return ret;
615}
616
617static void xenfb_disconnect_backend(struct xenfb_info *info)
618{
619	if (info->irq >= 0)
620		unbind_from_irqhandler(info->irq, info);
621	info->irq = -1;
622}
623
624static void xenfb_backend_changed(struct xenbus_device *dev,
625				  enum xenbus_state backend_state)
626{
627	struct xenfb_info *info = dev_get_drvdata(&dev->dev);
628	int val;
629
630	switch (backend_state) {
631	case XenbusStateInitialising:
632	case XenbusStateInitialised:
633	case XenbusStateUnknown:
634	case XenbusStateClosed:
635		break;
636
637	case XenbusStateInitWait:
638InitWait:
639		xenbus_switch_state(dev, XenbusStateConnected);
640		break;
641
642	case XenbusStateConnected:
643		/*
644		 * Work around xenbus race condition: If backend goes
645		 * through InitWait to Connected fast enough, we can
646		 * get Connected twice here.
647		 */
648		if (dev->state != XenbusStateConnected)
649			goto InitWait; /* no InitWait seen yet, fudge it */
650
651		if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
652				 "request-update", "%d", &val) < 0)
653			val = 0;
654		if (val)
655			info->update_wanted = 1;
656
657		if (xenbus_scanf(XBT_NIL, dev->otherend,
658				 "feature-resize", "%d", &val) < 0)
659			val = 0;
660		info->feature_resize = val;
661		break;
662
663	case XenbusStateClosing:
664		xenbus_frontend_closed(dev);
665		break;
666	}
667}
668
669static struct xenbus_device_id xenfb_ids[] = {
670	{ "vfb" },
671	{ "" }
672};
673
674static struct xenbus_driver xenfb_driver = {
675	.name = "vfb",
676	.owner = THIS_MODULE,
677	.ids = xenfb_ids,
678	.probe = xenfb_probe,
679	.remove = xenfb_remove,
680	.resume = xenfb_resume,
681	.otherend_changed = xenfb_backend_changed,
682};
683
684static int __init xenfb_init(void)
685{
686	if (!xen_domain())
687		return -ENODEV;
688
689	/* Nothing to do if running in dom0. */
690	if (xen_initial_domain())
691		return -ENODEV;
692
693	return xenbus_register_frontend(&xenfb_driver);
694}
695
696static void __exit xenfb_cleanup(void)
697{
698	xenbus_unregister_driver(&xenfb_driver);
699}
700
701module_init(xenfb_init);
702module_exit(xenfb_cleanup);
703
704MODULE_DESCRIPTION("Xen virtual framebuffer device frontend");
705MODULE_LICENSE("GPL");
706MODULE_ALIAS("xen:vfb");
707