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 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 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 } 105 106 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 } 116 117 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 } 125 126 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 } 139 140 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 } 183 184 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 }; 212 213 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 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 } 274 275 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 } 293 294 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 } 300 301 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 }; 320 321 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 } 341 342 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_obj(*info); 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(info->nr_pages, sizeof(unsigned long)); 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 ret = fb_deferred_io_init(fb_info); 447 if (ret < 0) { 448 xenbus_dev_fatal(dev, ret, "fb_deferred_io_init"); 449 goto error_cmap; 450 } 451 452 xenfb_init_shared_page(info, fb_info); 453 454 ret = xenfb_connect_backend(dev, info); 455 if (ret < 0) { 456 xenbus_dev_fatal(dev, ret, "xenfb_connect_backend"); 457 goto error_fb; 458 } 459 460 ret = register_framebuffer(fb_info); 461 if (ret) { 462 xenbus_dev_fatal(dev, ret, "register_framebuffer"); 463 goto error_fb; 464 } 465 info->fb_info = fb_info; 466 467 xenfb_make_preferred_console(); 468 return 0; 469 470 error_fb: 471 fb_deferred_io_cleanup(fb_info); 472 error_cmap: 473 fb_dealloc_cmap(&fb_info->cmap); 474 framebuffer_release(fb_info); 475 error_nomem: 476 if (!ret) { 477 ret = -ENOMEM; 478 xenbus_dev_fatal(dev, ret, "allocating device memory"); 479 } 480 error: 481 xenfb_remove(dev); 482 return ret; 483 } 484 485 static void xenfb_make_preferred_console(void) 486 { 487 struct console *c; 488 489 if (console_set_on_cmdline) 490 return; 491 492 console_list_lock(); 493 for_each_console(c) { 494 if (!strcmp(c->name, "tty") && c->index == 0) 495 break; 496 } 497 if (c) 498 console_force_preferred_locked(c); 499 console_list_unlock(); 500 } 501 502 static int xenfb_resume(struct xenbus_device *dev) 503 { 504 struct xenfb_info *info = dev_get_drvdata(&dev->dev); 505 506 xenfb_disconnect_backend(info); 507 xenfb_init_shared_page(info, info->fb_info); 508 return xenfb_connect_backend(dev, info); 509 } 510 511 static void xenfb_remove(struct xenbus_device *dev) 512 { 513 struct xenfb_info *info = dev_get_drvdata(&dev->dev); 514 515 xenfb_disconnect_backend(info); 516 if (info->fb_info) { 517 fb_deferred_io_cleanup(info->fb_info); 518 unregister_framebuffer(info->fb_info); 519 fb_dealloc_cmap(&info->fb_info->cmap); 520 framebuffer_release(info->fb_info); 521 } 522 free_page((unsigned long)info->page); 523 vfree(info->gfns); 524 vfree(info->fb); 525 kfree(info); 526 } 527 528 static unsigned long vmalloc_to_gfn(void *address) 529 { 530 return xen_page_to_gfn(vmalloc_to_page(address)); 531 } 532 533 static void xenfb_init_shared_page(struct xenfb_info *info, 534 struct fb_info *fb_info) 535 { 536 int i; 537 int epd = PAGE_SIZE / sizeof(info->gfns[0]); 538 539 for (i = 0; i < info->nr_pages; i++) 540 info->gfns[i] = vmalloc_to_gfn(info->fb + i * PAGE_SIZE); 541 542 for (i = 0; i * epd < info->nr_pages; i++) 543 info->page->pd[i] = vmalloc_to_gfn(&info->gfns[i * epd]); 544 545 info->page->width = fb_info->var.xres; 546 info->page->height = fb_info->var.yres; 547 info->page->depth = fb_info->var.bits_per_pixel; 548 info->page->line_length = fb_info->fix.line_length; 549 info->page->mem_length = fb_info->fix.smem_len; 550 info->page->in_cons = info->page->in_prod = 0; 551 info->page->out_cons = info->page->out_prod = 0; 552 } 553 554 static int xenfb_connect_backend(struct xenbus_device *dev, 555 struct xenfb_info *info) 556 { 557 int ret, evtchn, irq; 558 struct xenbus_transaction xbt; 559 560 ret = xenbus_alloc_evtchn(dev, &evtchn); 561 if (ret) 562 return ret; 563 irq = bind_evtchn_to_irqhandler(evtchn, xenfb_event_handler, 564 0, dev->devicetype, info); 565 if (irq < 0) { 566 xenbus_free_evtchn(dev, evtchn); 567 xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler"); 568 return irq; 569 } 570 again: 571 ret = xenbus_transaction_start(&xbt); 572 if (ret) { 573 xenbus_dev_fatal(dev, ret, "starting transaction"); 574 goto unbind_irq; 575 } 576 ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu", 577 virt_to_gfn(info->page)); 578 if (ret) 579 goto error_xenbus; 580 ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u", 581 evtchn); 582 if (ret) 583 goto error_xenbus; 584 ret = xenbus_printf(xbt, dev->nodename, "protocol", "%s", 585 XEN_IO_PROTO_ABI_NATIVE); 586 if (ret) 587 goto error_xenbus; 588 ret = xenbus_printf(xbt, dev->nodename, "feature-update", "1"); 589 if (ret) 590 goto error_xenbus; 591 ret = xenbus_transaction_end(xbt, 0); 592 if (ret) { 593 if (ret == -EAGAIN) 594 goto again; 595 xenbus_dev_fatal(dev, ret, "completing transaction"); 596 goto unbind_irq; 597 } 598 599 xenbus_switch_state(dev, XenbusStateInitialised); 600 info->irq = irq; 601 return 0; 602 603 error_xenbus: 604 xenbus_transaction_end(xbt, 1); 605 xenbus_dev_fatal(dev, ret, "writing xenstore"); 606 unbind_irq: 607 unbind_from_irqhandler(irq, info); 608 return ret; 609 } 610 611 static void xenfb_disconnect_backend(struct xenfb_info *info) 612 { 613 /* Prevent xenfb refresh */ 614 info->update_wanted = 0; 615 if (info->irq >= 0) 616 unbind_from_irqhandler(info->irq, info); 617 info->irq = -1; 618 } 619 620 static void xenfb_backend_changed(struct xenbus_device *dev, 621 enum xenbus_state backend_state) 622 { 623 struct xenfb_info *info = dev_get_drvdata(&dev->dev); 624 625 switch (backend_state) { 626 case XenbusStateInitialising: 627 case XenbusStateInitialised: 628 case XenbusStateReconfiguring: 629 case XenbusStateReconfigured: 630 case XenbusStateUnknown: 631 break; 632 633 case XenbusStateInitWait: 634 xenbus_switch_state(dev, XenbusStateConnected); 635 break; 636 637 case XenbusStateConnected: 638 /* 639 * Work around xenbus race condition: If backend goes 640 * through InitWait to Connected fast enough, we can 641 * get Connected twice here. 642 */ 643 if (dev->state != XenbusStateConnected) 644 /* no InitWait seen yet, fudge it */ 645 xenbus_switch_state(dev, XenbusStateConnected); 646 647 if (xenbus_read_unsigned(info->xbdev->otherend, 648 "request-update", 0)) 649 info->update_wanted = 1; 650 651 info->feature_resize = xenbus_read_unsigned(dev->otherend, 652 "feature-resize", 0); 653 break; 654 655 case XenbusStateClosed: 656 if (dev->state == XenbusStateClosed) 657 break; 658 fallthrough; /* Missed the backend's CLOSING state */ 659 case XenbusStateClosing: 660 xenbus_frontend_closed(dev); 661 break; 662 } 663 } 664 665 static const struct xenbus_device_id xenfb_ids[] = { 666 { "vfb" }, 667 { "" } 668 }; 669 670 static struct xenbus_driver xenfb_driver = { 671 .ids = xenfb_ids, 672 .probe = xenfb_probe, 673 .remove = xenfb_remove, 674 .resume = xenfb_resume, 675 .otherend_changed = xenfb_backend_changed, 676 .not_essential = true, 677 }; 678 679 static int __init xenfb_init(void) 680 { 681 if (!xen_domain()) 682 return -ENODEV; 683 684 /* Nothing to do if running in dom0. */ 685 if (xen_initial_domain()) 686 return -ENODEV; 687 688 if (!xen_has_pv_devices()) 689 return -ENODEV; 690 691 return xenbus_register_frontend(&xenfb_driver); 692 } 693 694 static void __exit xenfb_cleanup(void) 695 { 696 xenbus_unregister_driver(&xenfb_driver); 697 } 698 699 module_init(xenfb_init); 700 module_exit(xenfb_cleanup); 701 702 MODULE_DESCRIPTION("Xen virtual framebuffer device frontend"); 703 MODULE_LICENSE("GPL"); 704 MODULE_ALIAS("xen:vfb"); 705