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 int 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, 185 struct list_head *pagelist) 186 { 187 struct xenfb_info *info = fb_info->par; 188 struct page *page; 189 unsigned long beg, end; 190 int y1, y2, miny, maxy; 191 192 miny = INT_MAX; 193 maxy = 0; 194 list_for_each_entry(page, pagelist, lru) { 195 beg = page->index << PAGE_SHIFT; 196 end = beg + PAGE_SIZE - 1; 197 y1 = beg / fb_info->fix.line_length; 198 y2 = end / fb_info->fix.line_length; 199 if (y2 >= fb_info->var.yres) 200 y2 = fb_info->var.yres - 1; 201 if (miny > y1) 202 miny = y1; 203 if (maxy < y2) 204 maxy = y2; 205 } 206 xenfb_refresh(info, 0, miny, fb_info->var.xres, maxy - miny + 1); 207 } 208 209 static struct fb_deferred_io xenfb_defio = { 210 .delay = HZ / 20, 211 .deferred_io = xenfb_deferred_io, 212 }; 213 214 static int xenfb_setcolreg(unsigned regno, unsigned red, unsigned green, 215 unsigned blue, unsigned transp, 216 struct fb_info *info) 217 { 218 u32 v; 219 220 if (regno > info->cmap.len) 221 return 1; 222 223 #define CNVT_TOHW(val, width) ((((val)<<(width))+0x7FFF-(val))>>16) 224 red = CNVT_TOHW(red, info->var.red.length); 225 green = CNVT_TOHW(green, info->var.green.length); 226 blue = CNVT_TOHW(blue, info->var.blue.length); 227 transp = CNVT_TOHW(transp, info->var.transp.length); 228 #undef CNVT_TOHW 229 230 v = (red << info->var.red.offset) | 231 (green << info->var.green.offset) | 232 (blue << info->var.blue.offset); 233 234 switch (info->var.bits_per_pixel) { 235 case 16: 236 case 24: 237 case 32: 238 ((u32 *)info->pseudo_palette)[regno] = v; 239 break; 240 } 241 242 return 0; 243 } 244 245 static void xenfb_fillrect(struct fb_info *p, const struct fb_fillrect *rect) 246 { 247 struct xenfb_info *info = p->par; 248 249 sys_fillrect(p, rect); 250 xenfb_refresh(info, rect->dx, rect->dy, rect->width, rect->height); 251 } 252 253 static void xenfb_imageblit(struct fb_info *p, const struct fb_image *image) 254 { 255 struct xenfb_info *info = p->par; 256 257 sys_imageblit(p, image); 258 xenfb_refresh(info, image->dx, image->dy, image->width, image->height); 259 } 260 261 static void xenfb_copyarea(struct fb_info *p, const struct fb_copyarea *area) 262 { 263 struct xenfb_info *info = p->par; 264 265 sys_copyarea(p, area); 266 xenfb_refresh(info, area->dx, area->dy, area->width, area->height); 267 } 268 269 static ssize_t xenfb_write(struct fb_info *p, const char __user *buf, 270 size_t count, loff_t *ppos) 271 { 272 struct xenfb_info *info = p->par; 273 ssize_t res; 274 275 res = fb_sys_write(p, buf, count, ppos); 276 xenfb_refresh(info, 0, 0, info->page->width, info->page->height); 277 return res; 278 } 279 280 static int 281 xenfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info) 282 { 283 struct xenfb_info *xenfb_info; 284 int required_mem_len; 285 286 xenfb_info = info->par; 287 288 if (!xenfb_info->feature_resize) { 289 if (var->xres == video[KPARAM_WIDTH] && 290 var->yres == video[KPARAM_HEIGHT] && 291 var->bits_per_pixel == xenfb_info->page->depth) { 292 return 0; 293 } 294 return -EINVAL; 295 } 296 297 /* Can't resize past initial width and height */ 298 if (var->xres > video[KPARAM_WIDTH] || var->yres > video[KPARAM_HEIGHT]) 299 return -EINVAL; 300 301 required_mem_len = var->xres * var->yres * xenfb_info->page->depth / 8; 302 if (var->bits_per_pixel == xenfb_info->page->depth && 303 var->xres <= info->fix.line_length / (XENFB_DEPTH / 8) && 304 required_mem_len <= info->fix.smem_len) { 305 var->xres_virtual = var->xres; 306 var->yres_virtual = var->yres; 307 return 0; 308 } 309 return -EINVAL; 310 } 311 312 static int xenfb_set_par(struct fb_info *info) 313 { 314 struct xenfb_info *xenfb_info; 315 unsigned long flags; 316 317 xenfb_info = info->par; 318 319 spin_lock_irqsave(&xenfb_info->resize_lock, flags); 320 xenfb_info->resize.type = XENFB_TYPE_RESIZE; 321 xenfb_info->resize.width = info->var.xres; 322 xenfb_info->resize.height = info->var.yres; 323 xenfb_info->resize.stride = info->fix.line_length; 324 xenfb_info->resize.depth = info->var.bits_per_pixel; 325 xenfb_info->resize.offset = 0; 326 xenfb_info->resize_dpy = 1; 327 spin_unlock_irqrestore(&xenfb_info->resize_lock, flags); 328 return 0; 329 } 330 331 static const struct fb_ops xenfb_fb_ops = { 332 .owner = THIS_MODULE, 333 .fb_read = fb_sys_read, 334 .fb_write = xenfb_write, 335 .fb_setcolreg = xenfb_setcolreg, 336 .fb_fillrect = xenfb_fillrect, 337 .fb_copyarea = xenfb_copyarea, 338 .fb_imageblit = xenfb_imageblit, 339 .fb_check_var = xenfb_check_var, 340 .fb_set_par = xenfb_set_par, 341 }; 342 343 static irqreturn_t xenfb_event_handler(int rq, void *dev_id) 344 { 345 /* 346 * No in events recognized, simply ignore them all. 347 * If you need to recognize some, see xen-kbdfront's 348 * input_handler() for how to do that. 349 */ 350 struct xenfb_info *info = dev_id; 351 struct xenfb_page *page = info->page; 352 353 if (page->in_cons != page->in_prod) { 354 info->page->in_cons = info->page->in_prod; 355 notify_remote_via_irq(info->irq); 356 } 357 358 /* Flush dirty rectangle: */ 359 xenfb_refresh(info, INT_MAX, INT_MAX, -INT_MAX, -INT_MAX); 360 361 return IRQ_HANDLED; 362 } 363 364 static int xenfb_probe(struct xenbus_device *dev, 365 const struct xenbus_device_id *id) 366 { 367 struct xenfb_info *info; 368 struct fb_info *fb_info; 369 int fb_size; 370 int val; 371 int ret = 0; 372 373 info = kzalloc(sizeof(*info), GFP_KERNEL); 374 if (info == NULL) { 375 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure"); 376 return -ENOMEM; 377 } 378 379 /* Limit kernel param videoram amount to what is in xenstore */ 380 if (xenbus_scanf(XBT_NIL, dev->otherend, "videoram", "%d", &val) == 1) { 381 if (val < video[KPARAM_MEM]) 382 video[KPARAM_MEM] = val; 383 } 384 385 video[KPARAM_WIDTH] = xenbus_read_unsigned(dev->otherend, "width", 386 video[KPARAM_WIDTH]); 387 video[KPARAM_HEIGHT] = xenbus_read_unsigned(dev->otherend, "height", 388 video[KPARAM_HEIGHT]); 389 390 /* If requested res does not fit in available memory, use default */ 391 fb_size = video[KPARAM_MEM] * 1024 * 1024; 392 if (video[KPARAM_WIDTH] * video[KPARAM_HEIGHT] * XENFB_DEPTH / 8 393 > fb_size) { 394 pr_warn("display parameters %d,%d,%d invalid, use defaults\n", 395 video[KPARAM_MEM], video[KPARAM_WIDTH], 396 video[KPARAM_HEIGHT]); 397 video[KPARAM_WIDTH] = XENFB_WIDTH; 398 video[KPARAM_HEIGHT] = XENFB_HEIGHT; 399 fb_size = XENFB_DEFAULT_FB_LEN; 400 } 401 402 dev_set_drvdata(&dev->dev, info); 403 info->xbdev = dev; 404 info->irq = -1; 405 info->x1 = info->y1 = INT_MAX; 406 spin_lock_init(&info->dirty_lock); 407 spin_lock_init(&info->resize_lock); 408 409 info->fb = vzalloc(fb_size); 410 if (info->fb == NULL) 411 goto error_nomem; 412 413 info->nr_pages = (fb_size + PAGE_SIZE - 1) >> PAGE_SHIFT; 414 415 info->gfns = vmalloc(array_size(sizeof(unsigned long), info->nr_pages)); 416 if (!info->gfns) 417 goto error_nomem; 418 419 /* set up shared page */ 420 info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO); 421 if (!info->page) 422 goto error_nomem; 423 424 /* abusing framebuffer_alloc() to allocate pseudo_palette */ 425 fb_info = framebuffer_alloc(sizeof(u32) * 256, NULL); 426 if (fb_info == NULL) 427 goto error_nomem; 428 429 /* complete the abuse: */ 430 fb_info->pseudo_palette = fb_info->par; 431 fb_info->par = info; 432 433 fb_info->screen_base = info->fb; 434 435 fb_info->fbops = &xenfb_fb_ops; 436 fb_info->var.xres_virtual = fb_info->var.xres = video[KPARAM_WIDTH]; 437 fb_info->var.yres_virtual = fb_info->var.yres = video[KPARAM_HEIGHT]; 438 fb_info->var.bits_per_pixel = XENFB_DEPTH; 439 440 fb_info->var.red = (struct fb_bitfield){16, 8, 0}; 441 fb_info->var.green = (struct fb_bitfield){8, 8, 0}; 442 fb_info->var.blue = (struct fb_bitfield){0, 8, 0}; 443 444 fb_info->var.activate = FB_ACTIVATE_NOW; 445 fb_info->var.height = -1; 446 fb_info->var.width = -1; 447 fb_info->var.vmode = FB_VMODE_NONINTERLACED; 448 449 fb_info->fix.visual = FB_VISUAL_TRUECOLOR; 450 fb_info->fix.line_length = fb_info->var.xres * XENFB_DEPTH / 8; 451 fb_info->fix.smem_start = 0; 452 fb_info->fix.smem_len = fb_size; 453 strcpy(fb_info->fix.id, "xen"); 454 fb_info->fix.type = FB_TYPE_PACKED_PIXELS; 455 fb_info->fix.accel = FB_ACCEL_NONE; 456 457 fb_info->flags = FBINFO_FLAG_DEFAULT | FBINFO_VIRTFB; 458 459 ret = fb_alloc_cmap(&fb_info->cmap, 256, 0); 460 if (ret < 0) { 461 framebuffer_release(fb_info); 462 xenbus_dev_fatal(dev, ret, "fb_alloc_cmap"); 463 goto error; 464 } 465 466 fb_info->fbdefio = &xenfb_defio; 467 fb_deferred_io_init(fb_info); 468 469 xenfb_init_shared_page(info, fb_info); 470 471 ret = xenfb_connect_backend(dev, info); 472 if (ret < 0) { 473 xenbus_dev_fatal(dev, ret, "xenfb_connect_backend"); 474 goto error_fb; 475 } 476 477 ret = register_framebuffer(fb_info); 478 if (ret) { 479 xenbus_dev_fatal(dev, ret, "register_framebuffer"); 480 goto error_fb; 481 } 482 info->fb_info = fb_info; 483 484 xenfb_make_preferred_console(); 485 return 0; 486 487 error_fb: 488 fb_deferred_io_cleanup(fb_info); 489 fb_dealloc_cmap(&fb_info->cmap); 490 framebuffer_release(fb_info); 491 error_nomem: 492 if (!ret) { 493 ret = -ENOMEM; 494 xenbus_dev_fatal(dev, ret, "allocating device memory"); 495 } 496 error: 497 xenfb_remove(dev); 498 return ret; 499 } 500 501 static void xenfb_make_preferred_console(void) 502 { 503 struct console *c; 504 505 if (console_set_on_cmdline) 506 return; 507 508 console_lock(); 509 for_each_console(c) { 510 if (!strcmp(c->name, "tty") && c->index == 0) 511 break; 512 } 513 console_unlock(); 514 if (c) { 515 unregister_console(c); 516 c->flags |= CON_CONSDEV; 517 c->flags &= ~CON_PRINTBUFFER; /* don't print again */ 518 register_console(c); 519 } 520 } 521 522 static int xenfb_resume(struct xenbus_device *dev) 523 { 524 struct xenfb_info *info = dev_get_drvdata(&dev->dev); 525 526 xenfb_disconnect_backend(info); 527 xenfb_init_shared_page(info, info->fb_info); 528 return xenfb_connect_backend(dev, info); 529 } 530 531 static int xenfb_remove(struct xenbus_device *dev) 532 { 533 struct xenfb_info *info = dev_get_drvdata(&dev->dev); 534 535 xenfb_disconnect_backend(info); 536 if (info->fb_info) { 537 fb_deferred_io_cleanup(info->fb_info); 538 unregister_framebuffer(info->fb_info); 539 fb_dealloc_cmap(&info->fb_info->cmap); 540 framebuffer_release(info->fb_info); 541 } 542 free_page((unsigned long)info->page); 543 vfree(info->gfns); 544 vfree(info->fb); 545 kfree(info); 546 547 return 0; 548 } 549 550 static unsigned long vmalloc_to_gfn(void *address) 551 { 552 return xen_page_to_gfn(vmalloc_to_page(address)); 553 } 554 555 static void xenfb_init_shared_page(struct xenfb_info *info, 556 struct fb_info *fb_info) 557 { 558 int i; 559 int epd = PAGE_SIZE / sizeof(info->gfns[0]); 560 561 for (i = 0; i < info->nr_pages; i++) 562 info->gfns[i] = vmalloc_to_gfn(info->fb + i * PAGE_SIZE); 563 564 for (i = 0; i * epd < info->nr_pages; i++) 565 info->page->pd[i] = vmalloc_to_gfn(&info->gfns[i * epd]); 566 567 info->page->width = fb_info->var.xres; 568 info->page->height = fb_info->var.yres; 569 info->page->depth = fb_info->var.bits_per_pixel; 570 info->page->line_length = fb_info->fix.line_length; 571 info->page->mem_length = fb_info->fix.smem_len; 572 info->page->in_cons = info->page->in_prod = 0; 573 info->page->out_cons = info->page->out_prod = 0; 574 } 575 576 static int xenfb_connect_backend(struct xenbus_device *dev, 577 struct xenfb_info *info) 578 { 579 int ret, evtchn, irq; 580 struct xenbus_transaction xbt; 581 582 ret = xenbus_alloc_evtchn(dev, &evtchn); 583 if (ret) 584 return ret; 585 irq = bind_evtchn_to_irqhandler(evtchn, xenfb_event_handler, 586 0, dev->devicetype, info); 587 if (irq < 0) { 588 xenbus_free_evtchn(dev, evtchn); 589 xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler"); 590 return irq; 591 } 592 again: 593 ret = xenbus_transaction_start(&xbt); 594 if (ret) { 595 xenbus_dev_fatal(dev, ret, "starting transaction"); 596 goto unbind_irq; 597 } 598 ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu", 599 virt_to_gfn(info->page)); 600 if (ret) 601 goto error_xenbus; 602 ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u", 603 evtchn); 604 if (ret) 605 goto error_xenbus; 606 ret = xenbus_printf(xbt, dev->nodename, "protocol", "%s", 607 XEN_IO_PROTO_ABI_NATIVE); 608 if (ret) 609 goto error_xenbus; 610 ret = xenbus_printf(xbt, dev->nodename, "feature-update", "1"); 611 if (ret) 612 goto error_xenbus; 613 ret = xenbus_transaction_end(xbt, 0); 614 if (ret) { 615 if (ret == -EAGAIN) 616 goto again; 617 xenbus_dev_fatal(dev, ret, "completing transaction"); 618 goto unbind_irq; 619 } 620 621 xenbus_switch_state(dev, XenbusStateInitialised); 622 info->irq = irq; 623 return 0; 624 625 error_xenbus: 626 xenbus_transaction_end(xbt, 1); 627 xenbus_dev_fatal(dev, ret, "writing xenstore"); 628 unbind_irq: 629 unbind_from_irqhandler(irq, info); 630 return ret; 631 } 632 633 static void xenfb_disconnect_backend(struct xenfb_info *info) 634 { 635 /* Prevent xenfb refresh */ 636 info->update_wanted = 0; 637 if (info->irq >= 0) 638 unbind_from_irqhandler(info->irq, info); 639 info->irq = -1; 640 } 641 642 static void xenfb_backend_changed(struct xenbus_device *dev, 643 enum xenbus_state backend_state) 644 { 645 struct xenfb_info *info = dev_get_drvdata(&dev->dev); 646 647 switch (backend_state) { 648 case XenbusStateInitialising: 649 case XenbusStateInitialised: 650 case XenbusStateReconfiguring: 651 case XenbusStateReconfigured: 652 case XenbusStateUnknown: 653 break; 654 655 case XenbusStateInitWait: 656 xenbus_switch_state(dev, XenbusStateConnected); 657 break; 658 659 case XenbusStateConnected: 660 /* 661 * Work around xenbus race condition: If backend goes 662 * through InitWait to Connected fast enough, we can 663 * get Connected twice here. 664 */ 665 if (dev->state != XenbusStateConnected) 666 /* no InitWait seen yet, fudge it */ 667 xenbus_switch_state(dev, XenbusStateConnected); 668 669 if (xenbus_read_unsigned(info->xbdev->otherend, 670 "request-update", 0)) 671 info->update_wanted = 1; 672 673 info->feature_resize = xenbus_read_unsigned(dev->otherend, 674 "feature-resize", 0); 675 break; 676 677 case XenbusStateClosed: 678 if (dev->state == XenbusStateClosed) 679 break; 680 fallthrough; /* Missed the backend's CLOSING state */ 681 case XenbusStateClosing: 682 xenbus_frontend_closed(dev); 683 break; 684 } 685 } 686 687 static const struct xenbus_device_id xenfb_ids[] = { 688 { "vfb" }, 689 { "" } 690 }; 691 692 static struct xenbus_driver xenfb_driver = { 693 .ids = xenfb_ids, 694 .probe = xenfb_probe, 695 .remove = xenfb_remove, 696 .resume = xenfb_resume, 697 .otherend_changed = xenfb_backend_changed, 698 .not_essential = true, 699 }; 700 701 static int __init xenfb_init(void) 702 { 703 if (!xen_domain()) 704 return -ENODEV; 705 706 /* Nothing to do if running in dom0. */ 707 if (xen_initial_domain()) 708 return -ENODEV; 709 710 if (!xen_has_pv_devices()) 711 return -ENODEV; 712 713 return xenbus_register_frontend(&xenfb_driver); 714 } 715 716 static void __exit xenfb_cleanup(void) 717 { 718 xenbus_unregister_driver(&xenfb_driver); 719 } 720 721 module_init(xenfb_init); 722 module_exit(xenfb_cleanup); 723 724 MODULE_DESCRIPTION("Xen virtual framebuffer device frontend"); 725 MODULE_LICENSE("GPL"); 726 MODULE_ALIAS("xen:vfb"); 727