drivers/input/misc/xen-kbdfront.c

   1 /*
   2  * Xen para-virtual input device
   3  *
   4  * Copyright (C) 2005 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/input/mouse/sermouse.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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15
  16 #include <linux/kernel.h>
  17 #include <linux/errno.h>
  18 #include <linux/module.h>
  19 #include <linux/input.h>
  20 #include <linux/slab.h>
  21
  22 #include <asm/xen/hypervisor.h>
  23
  24 #include <xen/xen.h>
  25 #include <xen/events.h>
  26 #include <xen/page.h>
  27 #include <xen/grant_table.h>
  28 #include <xen/interface/grant_table.h>
  29 #include <xen/interface/io/fbif.h>
  30 #include <xen/interface/io/kbdif.h>
  31 #include <xen/xenbus.h>
  32 #include <xen/platform_pci.h>
  33
  34 struct xenkbd_info {
  35         struct input_dev *kbd;
  36         struct input_dev *ptr;
  37         struct xenkbd_page *page;
  38         int gref;
  39         int irq;
  40         struct xenbus_device *xbdev;
  41         char phys[32];
  42 };
  43
  44 static int xenkbd_remove(struct xenbus_device *);
  45 static int xenkbd_connect_backend(struct xenbus_device *, struct xenkbd_info *);
  46 static void xenkbd_disconnect_backend(struct xenkbd_info *);
  47
  48 /*
  49  * Note: if you need to send out events, see xenfb_do_update() for how
  50  * to do that.
  51  */
  52
  53 static irqreturn_t input_handler(int rq, void *dev_id)
  54 {
  55         struct xenkbd_info *info = dev_id;
  56         struct xenkbd_page *page = info->page;
  57         __u32 cons, prod;
  58
  59         prod = page->in_prod;
  60         if (prod == page->in_cons)
  61                 return IRQ_HANDLED;
  62         rmb();                  /* ensure we see ring contents up to prod */
  63         for (cons = page->in_cons; cons != prod; cons++) {
  64                 union xenkbd_in_event *event;
  65                 struct input_dev *dev;
  66                 event = &XENKBD_IN_RING_REF(page, cons);
  67
  68                 dev = info->ptr;
  69                 switch (event->type) {
  70                 case XENKBD_TYPE_MOTION:
  71                         input_report_rel(dev, REL_X, event->motion.rel_x);
  72                         input_report_rel(dev, REL_Y, event->motion.rel_y);
  73                         if (event->motion.rel_z)
  74                                 input_report_rel(dev, REL_WHEEL,
  75                                                  -event->motion.rel_z);
  76                         break;
  77                 case XENKBD_TYPE_KEY:
  78                         dev = NULL;
  79                         if (test_bit(event->key.keycode, info->kbd->keybit))
  80                                 dev = info->kbd;
  81                         if (test_bit(event->key.keycode, info->ptr->keybit))
  82                                 dev = info->ptr;
  83                         if (dev)
  84                                 input_report_key(dev, event->key.keycode,
  85                                                  event->key.pressed);
  86                         else
  87                                 pr_warning("unhandled keycode 0x%x\n",
  88                                            event->key.keycode);
  89                         break;
  90                 case XENKBD_TYPE_POS:
  91                         input_report_abs(dev, ABS_X, event->pos.abs_x);
  92                         input_report_abs(dev, ABS_Y, event->pos.abs_y);
  93                         if (event->pos.rel_z)
  94                                 input_report_rel(dev, REL_WHEEL,
  95                                                  -event->pos.rel_z);
  96                         break;
  97                 }
  98                 if (dev)
  99                         input_sync(dev);
 100         }
 101         mb();                   /* ensure we got ring contents */
 102         page->in_cons = cons;
 103         notify_remote_via_irq(info->irq);
 104
 105         return IRQ_HANDLED;
 106 }
 107
 108 static int xenkbd_probe(struct xenbus_device *dev,
 109                                   const struct xenbus_device_id *id)
 110 {
 111         int ret, i, abs;
 112         struct xenkbd_info *info;
 113         struct input_dev *kbd, *ptr;
 114
 115         info = kzalloc(sizeof(*info), GFP_KERNEL);
 116         if (!info) {
 117                 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
 118                 return -ENOMEM;
 119         }
 120         dev_set_drvdata(&dev->dev, info);
 121         info->xbdev = dev;
 122         info->irq = -1;
 123         info->gref = -1;
 124         snprintf(info->phys, sizeof(info->phys), "xenbus/%s", dev->nodename);
 125
 126         info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
 127         if (!info->page)
 128                 goto error_nomem;
 129
 130         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-abs-pointer", "%d", &abs) < 0)
 131                 abs = 0;
 132         if (abs)
 133                 xenbus_printf(XBT_NIL, dev->nodename, "request-abs-pointer", "1");
 134
 135         /* keyboard */
 136         kbd = input_allocate_device();
 137         if (!kbd)
 138                 goto error_nomem;
 139         kbd->name = "Xen Virtual Keyboard";
 140         kbd->phys = info->phys;
 141         kbd->id.bustype = BUS_PCI;
 142         kbd->id.vendor = 0x5853;
 143         kbd->id.product = 0xffff;
 144
 145         __set_bit(EV_KEY, kbd->evbit);
 146         for (i = KEY_ESC; i < KEY_UNKNOWN; i++)
 147                 __set_bit(i, kbd->keybit);
 148         for (i = KEY_OK; i < KEY_MAX; i++)
 149                 __set_bit(i, kbd->keybit);
 150
 151         ret = input_register_device(kbd);
 152         if (ret) {
 153                 input_free_device(kbd);
 154                 xenbus_dev_fatal(dev, ret, "input_register_device(kbd)");
 155                 goto error;
 156         }
 157         info->kbd = kbd;
 158
 159         /* pointing device */
 160         ptr = input_allocate_device();
 161         if (!ptr)
 162                 goto error_nomem;
 163         ptr->name = "Xen Virtual Pointer";
 164         ptr->phys = info->phys;
 165         ptr->id.bustype = BUS_PCI;
 166         ptr->id.vendor = 0x5853;
 167         ptr->id.product = 0xfffe;
 168
 169         if (abs) {
 170                 __set_bit(EV_ABS, ptr->evbit);
 171                 input_set_abs_params(ptr, ABS_X, 0, XENFB_WIDTH, 0, 0);
 172                 input_set_abs_params(ptr, ABS_Y, 0, XENFB_HEIGHT, 0, 0);
 173         } else {
 174                 input_set_capability(ptr, EV_REL, REL_X);
 175                 input_set_capability(ptr, EV_REL, REL_Y);
 176         }
 177         input_set_capability(ptr, EV_REL, REL_WHEEL);
 178
 179         __set_bit(EV_KEY, ptr->evbit);
 180         for (i = BTN_LEFT; i <= BTN_TASK; i++)
 181                 __set_bit(i, ptr->keybit);
 182
 183         ret = input_register_device(ptr);
 184         if (ret) {
 185                 input_free_device(ptr);
 186                 xenbus_dev_fatal(dev, ret, "input_register_device(ptr)");
 187                 goto error;
 188         }
 189         info->ptr = ptr;
 190
 191         ret = xenkbd_connect_backend(dev, info);
 192         if (ret < 0)
 193                 goto error;
 194
 195         return 0;
 196
 197  error_nomem:
 198         ret = -ENOMEM;
 199         xenbus_dev_fatal(dev, ret, "allocating device memory");
 200  error:
 201         xenkbd_remove(dev);
 202         return ret;
 203 }
 204
 205 static int xenkbd_resume(struct xenbus_device *dev)
 206 {
 207         struct xenkbd_info *info = dev_get_drvdata(&dev->dev);
 208
 209         xenkbd_disconnect_backend(info);
 210         memset(info->page, 0, PAGE_SIZE);
 211         return xenkbd_connect_backend(dev, info);
 212 }
 213
 214 static int xenkbd_remove(struct xenbus_device *dev)
 215 {
 216         struct xenkbd_info *info = dev_get_drvdata(&dev->dev);
 217
 218         xenkbd_disconnect_backend(info);
 219         if (info->kbd)
 220                 input_unregister_device(info->kbd);
 221         if (info->ptr)
 222                 input_unregister_device(info->ptr);
 223         free_page((unsigned long)info->page);
 224         kfree(info);
 225         return 0;
 226 }
 227
 228 static int xenkbd_connect_backend(struct xenbus_device *dev,
 229                                   struct xenkbd_info *info)
 230 {
 231         int ret, evtchn;
 232         struct xenbus_transaction xbt;
 233
 234         ret = gnttab_grant_foreign_access(dev->otherend_id,
 235                                           virt_to_gfn(info->page), 0);
 236         if (ret < 0)
 237                 return ret;
 238         info->gref = ret;
 239
 240         ret = xenbus_alloc_evtchn(dev, &evtchn);
 241         if (ret)
 242                 goto error_grant;
 243         ret = bind_evtchn_to_irqhandler(evtchn, input_handler,
 244                                         0, dev->devicetype, info);
 245         if (ret < 0) {
 246                 xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
 247                 goto error_evtchan;
 248         }
 249         info->irq = ret;
 250
 251  again:
 252         ret = xenbus_transaction_start(&xbt);
 253         if (ret) {
 254                 xenbus_dev_fatal(dev, ret, "starting transaction");
 255                 goto error_irqh;
 256         }
 257         ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
 258                             virt_to_gfn(info->page));
 259         if (ret)
 260                 goto error_xenbus;
 261         ret = xenbus_printf(xbt, dev->nodename, "page-gref", "%u", info->gref);
 262         if (ret)
 263                 goto error_xenbus;
 264         ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
 265                             evtchn);
 266         if (ret)
 267                 goto error_xenbus;
 268         ret = xenbus_transaction_end(xbt, 0);
 269         if (ret) {
 270                 if (ret == -EAGAIN)
 271                         goto again;
 272                 xenbus_dev_fatal(dev, ret, "completing transaction");
 273                 goto error_irqh;
 274         }
 275
 276         xenbus_switch_state(dev, XenbusStateInitialised);
 277         return 0;
 278
 279  error_xenbus:
 280         xenbus_transaction_end(xbt, 1);
 281         xenbus_dev_fatal(dev, ret, "writing xenstore");
 282  error_irqh:
 283         unbind_from_irqhandler(info->irq, info);
 284         info->irq = -1;
 285  error_evtchan:
 286         xenbus_free_evtchn(dev, evtchn);
 287  error_grant:
 288         gnttab_end_foreign_access(info->gref, 0, 0UL);
 289         info->gref = -1;
 290         return ret;
 291 }
 292
 293 static void xenkbd_disconnect_backend(struct xenkbd_info *info)
 294 {
 295         if (info->irq >= 0)
 296                 unbind_from_irqhandler(info->irq, info);
 297         info->irq = -1;
 298         if (info->gref >= 0)
 299                 gnttab_end_foreign_access(info->gref, 0, 0UL);
 300         info->gref = -1;
 301 }
 302
 303 static void xenkbd_backend_changed(struct xenbus_device *dev,
 304                                    enum xenbus_state backend_state)
 305 {
 306         struct xenkbd_info *info = dev_get_drvdata(&dev->dev);
 307         int ret, val;
 308
 309         switch (backend_state) {
 310         case XenbusStateInitialising:
 311         case XenbusStateInitialised:
 312         case XenbusStateReconfiguring:
 313         case XenbusStateReconfigured:
 314         case XenbusStateUnknown:
 315                 break;
 316
 317         case XenbusStateInitWait:
 318 InitWait:
 319                 ret = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
 320                                    "feature-abs-pointer", "%d", &val);
 321                 if (ret < 0)
 322                         val = 0;
 323                 if (val) {
 324                         ret = xenbus_printf(XBT_NIL, info->xbdev->nodename,
 325                                             "request-abs-pointer", "1");
 326                         if (ret)
 327                                 pr_warning("xenkbd: can't request abs-pointer");
 328                 }
 329
 330                 xenbus_switch_state(dev, XenbusStateConnected);
 331                 break;
 332
 333         case XenbusStateConnected:
 334                 /*
 335                  * Work around xenbus race condition: If backend goes
 336                  * through InitWait to Connected fast enough, we can
 337                  * get Connected twice here.
 338                  */
 339                 if (dev->state != XenbusStateConnected)
 340                         goto InitWait; /* no InitWait seen yet, fudge it */
 341
 342                 /* Set input abs params to match backend screen res */
 343                 if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
 344                                  "width", "%d", &val) > 0)
 345                         input_set_abs_params(info->ptr, ABS_X, 0, val, 0, 0);
 346
 347                 if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
 348                                  "height", "%d", &val) > 0)
 349                         input_set_abs_params(info->ptr, ABS_Y, 0, val, 0, 0);
 350
 351                 break;
 352
 353         case XenbusStateClosed:
 354                 if (dev->state == XenbusStateClosed)
 355                         break;
 356                 /* Missed the backend's CLOSING state -- fallthrough */
 357         case XenbusStateClosing:
 358                 xenbus_frontend_closed(dev);
 359                 break;
 360         }
 361 }
 362
 363 static const struct xenbus_device_id xenkbd_ids[] = {
 364         { "vkbd" },
 365         { "" }
 366 };
 367
 368 static struct xenbus_driver xenkbd_driver = {
 369         .ids = xenkbd_ids,
 370         .probe = xenkbd_probe,
 371         .remove = xenkbd_remove,
 372         .resume = xenkbd_resume,
 373         .otherend_changed = xenkbd_backend_changed,
 374 };
 375
 376 static int __init xenkbd_init(void)
 377 {
 378         if (!xen_domain())
 379                 return -ENODEV;
 380
 381         /* Nothing to do if running in dom0. */
 382         if (xen_initial_domain())
 383                 return -ENODEV;
 384
 385         if (!xen_has_pv_devices())
 386                 return -ENODEV;
 387
 388         return xenbus_register_frontend(&xenkbd_driver);
 389 }
 390
 391 static void __exit xenkbd_cleanup(void)
 392 {
 393         xenbus_unregister_driver(&xenkbd_driver);
 394 }
 395
 396 module_init(xenkbd_init);
 397 module_exit(xenkbd_cleanup);
 398
 399 MODULE_DESCRIPTION("Xen virtual keyboard/pointer device frontend");
 400 MODULE_LICENSE("GPL");
 401 MODULE_ALIAS("xen:vkbd");