Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm
[linux-2.6] / drivers / video / xen-fbfront.c
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/kernel.h>
22 #include <linux/errno.h>
23 #include <linux/fb.h>
24 #include <linux/module.h>
25 #include <linux/vmalloc.h>
26 #include <linux/mm.h>
27 #include <asm/xen/hypervisor.h>
28 #include <xen/events.h>
29 #include <xen/page.h>
30 #include <xen/interface/io/fbif.h>
31 #include <xen/interface/io/protocols.h>
32 #include <xen/xenbus.h>
33
34 struct xenfb_info {
35         unsigned char           *fb;
36         struct fb_info          *fb_info;
37         int                     x1, y1, x2, y2; /* dirty rectangle,
38                                                    protected by dirty_lock */
39         spinlock_t              dirty_lock;
40         int                     nr_pages;
41         int                     irq;
42         struct xenfb_page       *page;
43         unsigned long           *mfns;
44         int                     update_wanted; /* XENFB_TYPE_UPDATE wanted */
45
46         struct xenbus_device    *xbdev;
47 };
48
49 static u32 xenfb_mem_len = XENFB_WIDTH * XENFB_HEIGHT * XENFB_DEPTH / 8;
50
51 static int xenfb_remove(struct xenbus_device *);
52 static void xenfb_init_shared_page(struct xenfb_info *);
53 static int xenfb_connect_backend(struct xenbus_device *, struct xenfb_info *);
54 static void xenfb_disconnect_backend(struct xenfb_info *);
55
56 static void xenfb_do_update(struct xenfb_info *info,
57                             int x, int y, int w, int h)
58 {
59         union xenfb_out_event event;
60         u32 prod;
61
62         event.type = XENFB_TYPE_UPDATE;
63         event.update.x = x;
64         event.update.y = y;
65         event.update.width = w;
66         event.update.height = h;
67
68         prod = info->page->out_prod;
69         /* caller ensures !xenfb_queue_full() */
70         mb();                   /* ensure ring space available */
71         XENFB_OUT_RING_REF(info->page, prod) = event;
72         wmb();                  /* ensure ring contents visible */
73         info->page->out_prod = prod + 1;
74
75         notify_remote_via_irq(info->irq);
76 }
77
78 static int xenfb_queue_full(struct xenfb_info *info)
79 {
80         u32 cons, prod;
81
82         prod = info->page->out_prod;
83         cons = info->page->out_cons;
84         return prod - cons == XENFB_OUT_RING_LEN;
85 }
86
87 static void xenfb_refresh(struct xenfb_info *info,
88                           int x1, int y1, int w, int h)
89 {
90         unsigned long flags;
91         int y2 = y1 + h - 1;
92         int x2 = x1 + w - 1;
93
94         if (!info->update_wanted)
95                 return;
96
97         spin_lock_irqsave(&info->dirty_lock, flags);
98
99         /* Combine with dirty rectangle: */
100         if (info->y1 < y1)
101                 y1 = info->y1;
102         if (info->y2 > y2)
103                 y2 = info->y2;
104         if (info->x1 < x1)
105                 x1 = info->x1;
106         if (info->x2 > x2)
107                 x2 = info->x2;
108
109         if (xenfb_queue_full(info)) {
110                 /* Can't send right now, stash it in the dirty rectangle */
111                 info->x1 = x1;
112                 info->x2 = x2;
113                 info->y1 = y1;
114                 info->y2 = y2;
115                 spin_unlock_irqrestore(&info->dirty_lock, flags);
116                 return;
117         }
118
119         /* Clear dirty rectangle: */
120         info->x1 = info->y1 = INT_MAX;
121         info->x2 = info->y2 = 0;
122
123         spin_unlock_irqrestore(&info->dirty_lock, flags);
124
125         if (x1 <= x2 && y1 <= y2)
126                 xenfb_do_update(info, x1, y1, x2 - x1 + 1, y2 - y1 + 1);
127 }
128
129 static void xenfb_deferred_io(struct fb_info *fb_info,
130                               struct list_head *pagelist)
131 {
132         struct xenfb_info *info = fb_info->par;
133         struct page *page;
134         unsigned long beg, end;
135         int y1, y2, miny, maxy;
136
137         miny = INT_MAX;
138         maxy = 0;
139         list_for_each_entry(page, pagelist, lru) {
140                 beg = page->index << PAGE_SHIFT;
141                 end = beg + PAGE_SIZE - 1;
142                 y1 = beg / fb_info->fix.line_length;
143                 y2 = end / fb_info->fix.line_length;
144                 if (y2 >= fb_info->var.yres)
145                         y2 = fb_info->var.yres - 1;
146                 if (miny > y1)
147                         miny = y1;
148                 if (maxy < y2)
149                         maxy = y2;
150         }
151         xenfb_refresh(info, 0, miny, fb_info->var.xres, maxy - miny + 1);
152 }
153
154 static struct fb_deferred_io xenfb_defio = {
155         .delay          = HZ / 20,
156         .deferred_io    = xenfb_deferred_io,
157 };
158
159 static int xenfb_setcolreg(unsigned regno, unsigned red, unsigned green,
160                            unsigned blue, unsigned transp,
161                            struct fb_info *info)
162 {
163         u32 v;
164
165         if (regno > info->cmap.len)
166                 return 1;
167
168 #define CNVT_TOHW(val, width) ((((val)<<(width))+0x7FFF-(val))>>16)
169         red = CNVT_TOHW(red, info->var.red.length);
170         green = CNVT_TOHW(green, info->var.green.length);
171         blue = CNVT_TOHW(blue, info->var.blue.length);
172         transp = CNVT_TOHW(transp, info->var.transp.length);
173 #undef CNVT_TOHW
174
175         v = (red << info->var.red.offset) |
176             (green << info->var.green.offset) |
177             (blue << info->var.blue.offset);
178
179         switch (info->var.bits_per_pixel) {
180         case 16:
181         case 24:
182         case 32:
183                 ((u32 *)info->pseudo_palette)[regno] = v;
184                 break;
185         }
186
187         return 0;
188 }
189
190 static void xenfb_fillrect(struct fb_info *p, const struct fb_fillrect *rect)
191 {
192         struct xenfb_info *info = p->par;
193
194         sys_fillrect(p, rect);
195         xenfb_refresh(info, rect->dx, rect->dy, rect->width, rect->height);
196 }
197
198 static void xenfb_imageblit(struct fb_info *p, const struct fb_image *image)
199 {
200         struct xenfb_info *info = p->par;
201
202         sys_imageblit(p, image);
203         xenfb_refresh(info, image->dx, image->dy, image->width, image->height);
204 }
205
206 static void xenfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
207 {
208         struct xenfb_info *info = p->par;
209
210         sys_copyarea(p, area);
211         xenfb_refresh(info, area->dx, area->dy, area->width, area->height);
212 }
213
214 static ssize_t xenfb_write(struct fb_info *p, const char __user *buf,
215                         size_t count, loff_t *ppos)
216 {
217         struct xenfb_info *info = p->par;
218         ssize_t res;
219
220         res = fb_sys_write(p, buf, count, ppos);
221         xenfb_refresh(info, 0, 0, info->page->width, info->page->height);
222         return res;
223 }
224
225 static struct fb_ops xenfb_fb_ops = {
226         .owner          = THIS_MODULE,
227         .fb_read        = fb_sys_read,
228         .fb_write       = xenfb_write,
229         .fb_setcolreg   = xenfb_setcolreg,
230         .fb_fillrect    = xenfb_fillrect,
231         .fb_copyarea    = xenfb_copyarea,
232         .fb_imageblit   = xenfb_imageblit,
233 };
234
235 static irqreturn_t xenfb_event_handler(int rq, void *dev_id)
236 {
237         /*
238          * No in events recognized, simply ignore them all.
239          * If you need to recognize some, see xen-kbdfront's
240          * input_handler() for how to do that.
241          */
242         struct xenfb_info *info = dev_id;
243         struct xenfb_page *page = info->page;
244
245         if (page->in_cons != page->in_prod) {
246                 info->page->in_cons = info->page->in_prod;
247                 notify_remote_via_irq(info->irq);
248         }
249
250         /* Flush dirty rectangle: */
251         xenfb_refresh(info, INT_MAX, INT_MAX, -INT_MAX, -INT_MAX);
252
253         return IRQ_HANDLED;
254 }
255
256 static int __devinit xenfb_probe(struct xenbus_device *dev,
257                                  const struct xenbus_device_id *id)
258 {
259         struct xenfb_info *info;
260         struct fb_info *fb_info;
261         int ret;
262
263         info = kzalloc(sizeof(*info), GFP_KERNEL);
264         if (info == NULL) {
265                 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
266                 return -ENOMEM;
267         }
268         dev->dev.driver_data = info;
269         info->xbdev = dev;
270         info->irq = -1;
271         info->x1 = info->y1 = INT_MAX;
272         spin_lock_init(&info->dirty_lock);
273
274         info->fb = vmalloc(xenfb_mem_len);
275         if (info->fb == NULL)
276                 goto error_nomem;
277         memset(info->fb, 0, xenfb_mem_len);
278
279         info->nr_pages = (xenfb_mem_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
280
281         info->mfns = vmalloc(sizeof(unsigned long) * info->nr_pages);
282         if (!info->mfns)
283                 goto error_nomem;
284
285         /* set up shared page */
286         info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
287         if (!info->page)
288                 goto error_nomem;
289
290         xenfb_init_shared_page(info);
291
292         /* abusing framebuffer_alloc() to allocate pseudo_palette */
293         fb_info = framebuffer_alloc(sizeof(u32) * 256, NULL);
294         if (fb_info == NULL)
295                 goto error_nomem;
296
297         /* complete the abuse: */
298         fb_info->pseudo_palette = fb_info->par;
299         fb_info->par = info;
300
301         fb_info->screen_base = info->fb;
302
303         fb_info->fbops = &xenfb_fb_ops;
304         fb_info->var.xres_virtual = fb_info->var.xres = info->page->width;
305         fb_info->var.yres_virtual = fb_info->var.yres = info->page->height;
306         fb_info->var.bits_per_pixel = info->page->depth;
307
308         fb_info->var.red = (struct fb_bitfield){16, 8, 0};
309         fb_info->var.green = (struct fb_bitfield){8, 8, 0};
310         fb_info->var.blue = (struct fb_bitfield){0, 8, 0};
311
312         fb_info->var.activate = FB_ACTIVATE_NOW;
313         fb_info->var.height = -1;
314         fb_info->var.width = -1;
315         fb_info->var.vmode = FB_VMODE_NONINTERLACED;
316
317         fb_info->fix.visual = FB_VISUAL_TRUECOLOR;
318         fb_info->fix.line_length = info->page->line_length;
319         fb_info->fix.smem_start = 0;
320         fb_info->fix.smem_len = xenfb_mem_len;
321         strcpy(fb_info->fix.id, "xen");
322         fb_info->fix.type = FB_TYPE_PACKED_PIXELS;
323         fb_info->fix.accel = FB_ACCEL_NONE;
324
325         fb_info->flags = FBINFO_FLAG_DEFAULT;
326
327         ret = fb_alloc_cmap(&fb_info->cmap, 256, 0);
328         if (ret < 0) {
329                 framebuffer_release(fb_info);
330                 xenbus_dev_fatal(dev, ret, "fb_alloc_cmap");
331                 goto error;
332         }
333
334         fb_info->fbdefio = &xenfb_defio;
335         fb_deferred_io_init(fb_info);
336
337         ret = register_framebuffer(fb_info);
338         if (ret) {
339                 fb_deferred_io_cleanup(fb_info);
340                 fb_dealloc_cmap(&fb_info->cmap);
341                 framebuffer_release(fb_info);
342                 xenbus_dev_fatal(dev, ret, "register_framebuffer");
343                 goto error;
344         }
345         info->fb_info = fb_info;
346
347         ret = xenfb_connect_backend(dev, info);
348         if (ret < 0)
349                 goto error;
350
351         return 0;
352
353  error_nomem:
354         ret = -ENOMEM;
355         xenbus_dev_fatal(dev, ret, "allocating device memory");
356  error:
357         xenfb_remove(dev);
358         return ret;
359 }
360
361 static int xenfb_resume(struct xenbus_device *dev)
362 {
363         struct xenfb_info *info = dev->dev.driver_data;
364
365         xenfb_disconnect_backend(info);
366         xenfb_init_shared_page(info);
367         return xenfb_connect_backend(dev, info);
368 }
369
370 static int xenfb_remove(struct xenbus_device *dev)
371 {
372         struct xenfb_info *info = dev->dev.driver_data;
373
374         xenfb_disconnect_backend(info);
375         if (info->fb_info) {
376                 fb_deferred_io_cleanup(info->fb_info);
377                 unregister_framebuffer(info->fb_info);
378                 fb_dealloc_cmap(&info->fb_info->cmap);
379                 framebuffer_release(info->fb_info);
380         }
381         free_page((unsigned long)info->page);
382         vfree(info->mfns);
383         vfree(info->fb);
384         kfree(info);
385
386         return 0;
387 }
388
389 static unsigned long vmalloc_to_mfn(void *address)
390 {
391         return pfn_to_mfn(vmalloc_to_pfn(address));
392 }
393
394 static void xenfb_init_shared_page(struct xenfb_info *info)
395 {
396         int i;
397
398         for (i = 0; i < info->nr_pages; i++)
399                 info->mfns[i] = vmalloc_to_mfn(info->fb + i * PAGE_SIZE);
400
401         info->page->pd[0] = vmalloc_to_mfn(info->mfns);
402         info->page->pd[1] = 0;
403         info->page->width = XENFB_WIDTH;
404         info->page->height = XENFB_HEIGHT;
405         info->page->depth = XENFB_DEPTH;
406         info->page->line_length = (info->page->depth / 8) * info->page->width;
407         info->page->mem_length = xenfb_mem_len;
408         info->page->in_cons = info->page->in_prod = 0;
409         info->page->out_cons = info->page->out_prod = 0;
410 }
411
412 static int xenfb_connect_backend(struct xenbus_device *dev,
413                                  struct xenfb_info *info)
414 {
415         int ret, evtchn;
416         struct xenbus_transaction xbt;
417
418         ret = xenbus_alloc_evtchn(dev, &evtchn);
419         if (ret)
420                 return ret;
421         ret = bind_evtchn_to_irqhandler(evtchn, xenfb_event_handler,
422                                         0, dev->devicetype, info);
423         if (ret < 0) {
424                 xenbus_free_evtchn(dev, evtchn);
425                 xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
426                 return ret;
427         }
428         info->irq = ret;
429
430  again:
431         ret = xenbus_transaction_start(&xbt);
432         if (ret) {
433                 xenbus_dev_fatal(dev, ret, "starting transaction");
434                 return ret;
435         }
436         ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
437                             virt_to_mfn(info->page));
438         if (ret)
439                 goto error_xenbus;
440         ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
441                             evtchn);
442         if (ret)
443                 goto error_xenbus;
444         ret = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
445                             XEN_IO_PROTO_ABI_NATIVE);
446         if (ret)
447                 goto error_xenbus;
448         ret = xenbus_printf(xbt, dev->nodename, "feature-update", "1");
449         if (ret)
450                 goto error_xenbus;
451         ret = xenbus_transaction_end(xbt, 0);
452         if (ret) {
453                 if (ret == -EAGAIN)
454                         goto again;
455                 xenbus_dev_fatal(dev, ret, "completing transaction");
456                 return ret;
457         }
458
459         xenbus_switch_state(dev, XenbusStateInitialised);
460         return 0;
461
462  error_xenbus:
463         xenbus_transaction_end(xbt, 1);
464         xenbus_dev_fatal(dev, ret, "writing xenstore");
465         return ret;
466 }
467
468 static void xenfb_disconnect_backend(struct xenfb_info *info)
469 {
470         if (info->irq >= 0)
471                 unbind_from_irqhandler(info->irq, info);
472         info->irq = -1;
473 }
474
475 static void xenfb_backend_changed(struct xenbus_device *dev,
476                                   enum xenbus_state backend_state)
477 {
478         struct xenfb_info *info = dev->dev.driver_data;
479         int val;
480
481         switch (backend_state) {
482         case XenbusStateInitialising:
483         case XenbusStateInitialised:
484         case XenbusStateUnknown:
485         case XenbusStateClosed:
486                 break;
487
488         case XenbusStateInitWait:
489 InitWait:
490                 xenbus_switch_state(dev, XenbusStateConnected);
491                 break;
492
493         case XenbusStateConnected:
494                 /*
495                  * Work around xenbus race condition: If backend goes
496                  * through InitWait to Connected fast enough, we can
497                  * get Connected twice here.
498                  */
499                 if (dev->state != XenbusStateConnected)
500                         goto InitWait; /* no InitWait seen yet, fudge it */
501
502                 if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
503                                  "request-update", "%d", &val) < 0)
504                         val = 0;
505                 if (val)
506                         info->update_wanted = 1;
507                 break;
508
509         case XenbusStateClosing:
510                 xenbus_frontend_closed(dev);
511                 break;
512         }
513 }
514
515 static struct xenbus_device_id xenfb_ids[] = {
516         { "vfb" },
517         { "" }
518 };
519
520 static struct xenbus_driver xenfb = {
521         .name = "vfb",
522         .owner = THIS_MODULE,
523         .ids = xenfb_ids,
524         .probe = xenfb_probe,
525         .remove = xenfb_remove,
526         .resume = xenfb_resume,
527         .otherend_changed = xenfb_backend_changed,
528 };
529
530 static int __init xenfb_init(void)
531 {
532         if (!is_running_on_xen())
533                 return -ENODEV;
534
535         /* Nothing to do if running in dom0. */
536         if (is_initial_xendomain())
537                 return -ENODEV;
538
539         return xenbus_register_frontend(&xenfb);
540 }
541
542 static void __exit xenfb_cleanup(void)
543 {
544         xenbus_unregister_driver(&xenfb);
545 }
546
547 module_init(xenfb_init);
548 module_exit(xenfb_cleanup);
549
550 MODULE_LICENSE("GPL");