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;
 112         unsigned int abs;
 113         struct xenkbd_info *info;
 114         struct input_dev *kbd, *ptr;
 115
 116         info = kzalloc(sizeof(*info), GFP_KERNEL);
 117         if (!info) {
 118                 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
 119                 return -ENOMEM;
 120         }
 121         dev_set_drvdata(&dev->dev, info);
 122         info->xbdev = dev;
 123         info->irq = -1;
 124         info->gref = -1;
 125         snprintf(info->phys, sizeof(info->phys), "xenbus/%s", dev->nodename);
 126
 127         info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
 128         if (!info->page)
 129                 goto error_nomem;
 130
 131         abs = xenbus_read_unsigned(dev->otherend, "feature-abs-pointer", 0);
 132         if (abs) {
 133                 ret = xenbus_write(XBT_NIL, dev->nodename,
 134                                    "request-abs-pointer", "1");
 135                 if (ret) {
 136                         pr_warning("xenkbd: can't request abs-pointer");
 137                         abs = 0;
 138                 }
 139         }
 140
 141         /* keyboard */
 142         kbd = input_allocate_device();
 143         if (!kbd)
 144                 goto error_nomem;
 145         kbd->name = "Xen Virtual Keyboard";
 146         kbd->phys = info->phys;
 147         kbd->id.bustype = BUS_PCI;
 148         kbd->id.vendor = 0x5853;
 149         kbd->id.product = 0xffff;
 150
 151         __set_bit(EV_KEY, kbd->evbit);
 152         for (i = KEY_ESC; i < KEY_UNKNOWN; i++)
 153                 __set_bit(i, kbd->keybit);
 154         for (i = KEY_OK; i < KEY_MAX; i++)
 155                 __set_bit(i, kbd->keybit);
 156
 157         ret = input_register_device(kbd);
 158         if (ret) {
 159                 input_free_device(kbd);
 160                 xenbus_dev_fatal(dev, ret, "input_register_device(kbd)");
 161                 goto error;
 162         }
 163         info->kbd = kbd;
 164
 165         /* pointing device */
 166         ptr = input_allocate_device();
 167         if (!ptr)
 168                 goto error_nomem;
 169         ptr->name = "Xen Virtual Pointer";
 170         ptr->phys = info->phys;
 171         ptr->id.bustype = BUS_PCI;
 172         ptr->id.vendor = 0x5853;
 173         ptr->id.product = 0xfffe;
 174
 175         if (abs) {
 176                 __set_bit(EV_ABS, ptr->evbit);
 177                 input_set_abs_params(ptr, ABS_X, 0, XENFB_WIDTH, 0, 0);
 178                 input_set_abs_params(ptr, ABS_Y, 0, XENFB_HEIGHT, 0, 0);
 179         } else {
 180                 input_set_capability(ptr, EV_REL, REL_X);
 181                 input_set_capability(ptr, EV_REL, REL_Y);
 182         }
 183         input_set_capability(ptr, EV_REL, REL_WHEEL);
 184
 185         __set_bit(EV_KEY, ptr->evbit);
 186         for (i = BTN_LEFT; i <= BTN_TASK; i++)
 187                 __set_bit(i, ptr->keybit);
 188
 189         ret = input_register_device(ptr);
 190         if (ret) {
 191                 input_free_device(ptr);
 192                 xenbus_dev_fatal(dev, ret, "input_register_device(ptr)");
 193                 goto error;
 194         }
 195         info->ptr = ptr;
 196
 197         ret = xenkbd_connect_backend(dev, info);
 198         if (ret < 0)
 199                 goto error;
 200
 201         return 0;
 202
 203  error_nomem:
 204         ret = -ENOMEM;
 205         xenbus_dev_fatal(dev, ret, "allocating device memory");
 206  error:
 207         xenkbd_remove(dev);
 208         return ret;
 209 }
 210
 211 static int xenkbd_resume(struct xenbus_device *dev)
 212 {
 213         struct xenkbd_info *info = dev_get_drvdata(&dev->dev);
 214
 215         xenkbd_disconnect_backend(info);
 216         memset(info->page, 0, PAGE_SIZE);
 217         return xenkbd_connect_backend(dev, info);
 218 }
 219
 220 static int xenkbd_remove(struct xenbus_device *dev)
 221 {
 222         struct xenkbd_info *info = dev_get_drvdata(&dev->dev);
 223
 224         xenkbd_disconnect_backend(info);
 225         if (info->kbd)
 226                 input_unregister_device(info->kbd);
 227         if (info->ptr)
 228                 input_unregister_device(info->ptr);
 229         free_page((unsigned long)info->page);
 230         kfree(info);
 231         return 0;
 232 }
 233
 234 static int xenkbd_connect_backend(struct xenbus_device *dev,
 235                                   struct xenkbd_info *info)
 236 {
 237         int ret, evtchn;
 238         struct xenbus_transaction xbt;
 239
 240         ret = gnttab_grant_foreign_access(dev->otherend_id,
 241                                           virt_to_gfn(info->page), 0);
 242         if (ret < 0)
 243                 return ret;
 244         info->gref = ret;
 245
 246         ret = xenbus_alloc_evtchn(dev, &evtchn);
 247         if (ret)
 248                 goto error_grant;
 249         ret = bind_evtchn_to_irqhandler(evtchn, input_handler,
 250                                         0, dev->devicetype, info);
 251         if (ret < 0) {
 252                 xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
 253                 goto error_evtchan;
 254         }
 255         info->irq = ret;
 256
 257  again:
 258         ret = xenbus_transaction_start(&xbt);
 259         if (ret) {
 260                 xenbus_dev_fatal(dev, ret, "starting transaction");
 261                 goto error_irqh;
 262         }
 263         ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
 264                             virt_to_gfn(info->page));
 265         if (ret)
 266                 goto error_xenbus;
 267         ret = xenbus_printf(xbt, dev->nodename, "page-gref", "%u", info->gref);
 268         if (ret)
 269                 goto error_xenbus;
 270         ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
 271                             evtchn);
 272         if (ret)
 273                 goto error_xenbus;
 274         ret = xenbus_transaction_end(xbt, 0);
 275         if (ret) {
 276                 if (ret == -EAGAIN)
 277                         goto again;
 278                 xenbus_dev_fatal(dev, ret, "completing transaction");
 279                 goto error_irqh;
 280         }
 281
 282         xenbus_switch_state(dev, XenbusStateInitialised);
 283         return 0;
 284
 285  error_xenbus:
 286         xenbus_transaction_end(xbt, 1);
 287         xenbus_dev_fatal(dev, ret, "writing xenstore");
 288  error_irqh:
 289         unbind_from_irqhandler(info->irq, info);
 290         info->irq = -1;
 291  error_evtchan:
 292         xenbus_free_evtchn(dev, evtchn);
 293  error_grant:
 294         gnttab_end_foreign_access(info->gref, 0, 0UL);
 295         info->gref = -1;
 296         return ret;
 297 }
 298
 299 static void xenkbd_disconnect_backend(struct xenkbd_info *info)
 300 {
 301         if (info->irq >= 0)
 302                 unbind_from_irqhandler(info->irq, info);
 303         info->irq = -1;
 304         if (info->gref >= 0)
 305                 gnttab_end_foreign_access(info->gref, 0, 0UL);
 306         info->gref = -1;
 307 }
 308
 309 static void xenkbd_backend_changed(struct xenbus_device *dev,
 310                                    enum xenbus_state backend_state)
 311 {
 312         struct xenkbd_info *info = dev_get_drvdata(&dev->dev);
 313         int ret, val;
 314
 315         switch (backend_state) {
 316         case XenbusStateInitialising:
 317         case XenbusStateInitialised:
 318         case XenbusStateReconfiguring:
 319         case XenbusStateReconfigured:
 320         case XenbusStateUnknown:
 321                 break;
 322
 323         case XenbusStateInitWait:
 324 InitWait:
 325                 if (xenbus_read_unsigned(info->xbdev->otherend,
 326                                          "feature-abs-pointer", 0)) {
 327                         ret = xenbus_write(XBT_NIL, info->xbdev->nodename,
 328                                            "request-abs-pointer", "1");
 329                         if (ret)
 330                                 pr_warning("xenkbd: can't request abs-pointer");
 331                 }
 332
 333                 xenbus_switch_state(dev, XenbusStateConnected);
 334                 break;
 335
 336         case XenbusStateConnected:
 337                 /*
 338                  * Work around xenbus race condition: If backend goes
 339                  * through InitWait to Connected fast enough, we can
 340                  * get Connected twice here.
 341                  */
 342                 if (dev->state != XenbusStateConnected)
 343                         goto InitWait; /* no InitWait seen yet, fudge it */
 344
 345                 /* Set input abs params to match backend screen res */
 346                 if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
 347                                  "width", "%d", &val) > 0)
 348                         input_set_abs_params(info->ptr, ABS_X, 0, val, 0, 0);
 349
 350                 if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
 351                                  "height", "%d", &val) > 0)
 352                         input_set_abs_params(info->ptr, ABS_Y, 0, val, 0, 0);
 353
 354                 break;
 355
 356         case XenbusStateClosed:
 357                 if (dev->state == XenbusStateClosed)
 358                         break;
 359                 /* Missed the backend's CLOSING state -- fallthrough */
 360         case XenbusStateClosing:
 361                 xenbus_frontend_closed(dev);
 362                 break;
 363         }
 364 }
 365
 366 static const struct xenbus_device_id xenkbd_ids[] = {
 367         { "vkbd" },
 368         { "" }
 369 };
 370
 371 static struct xenbus_driver xenkbd_driver = {
 372         .ids = xenkbd_ids,
 373         .probe = xenkbd_probe,
 374         .remove = xenkbd_remove,
 375         .resume = xenkbd_resume,
 376         .otherend_changed = xenkbd_backend_changed,
 377 };
 378
 379 static int __init xenkbd_init(void)
 380 {
 381         if (!xen_domain())
 382                 return -ENODEV;
 383
 384         /* Nothing to do if running in dom0. */
 385         if (xen_initial_domain())
 386                 return -ENODEV;
 387
 388         if (!xen_has_pv_devices())
 389                 return -ENODEV;
 390
 391         return xenbus_register_frontend(&xenkbd_driver);
 392 }
 393
 394 static void __exit xenkbd_cleanup(void)
 395 {
 396         xenbus_unregister_driver(&xenkbd_driver);
 397 }
 398
 399 module_init(xenkbd_init);
 400 module_exit(xenkbd_cleanup);
 401
 402 MODULE_DESCRIPTION("Xen virtual keyboard/pointer device frontend");
 403 MODULE_LICENSE("GPL");
 404 MODULE_ALIAS("xen:vkbd");