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");