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