drivers/virtio/virtio_input.c

   1 #include <linux/module.h>
   2 #include <linux/virtio.h>
   3 #include <linux/virtio_config.h>
   4 #include <linux/input.h>
   5
   6 #include <uapi/linux/virtio_ids.h>
   7 #include <uapi/linux/virtio_input.h>
   8
   9 struct virtio_input {
  10         struct virtio_device       *vdev;
  11         struct input_dev           *idev;
  12         char                       name[64];
  13         char                       serial[64];
  14         char                       phys[64];
  15         struct virtqueue           *evt, *sts;
  16         struct virtio_input_event  evts[64];
  17         spinlock_t                 lock;
  18         bool                       ready;
  19 };
  20
  21 static void virtinput_queue_evtbuf(struct virtio_input *vi,
  22                                    struct virtio_input_event *evtbuf)
  23 {
  24         struct scatterlist sg[1];
  25
  26         sg_init_one(sg, evtbuf, sizeof(*evtbuf));
  27         virtqueue_add_inbuf(vi->evt, sg, 1, evtbuf, GFP_ATOMIC);
  28 }
  29
  30 static void virtinput_recv_events(struct virtqueue *vq)
  31 {
  32         struct virtio_input *vi = vq->vdev->priv;
  33         struct virtio_input_event *event;
  34         unsigned long flags;
  35         unsigned int len;
  36
  37         spin_lock_irqsave(&vi->lock, flags);
  38         if (vi->ready) {
  39                 while ((event = virtqueue_get_buf(vi->evt, &len)) != NULL) {
  40                         spin_unlock_irqrestore(&vi->lock, flags);
  41                         input_event(vi->idev,
  42                                     le16_to_cpu(event->type),
  43                                     le16_to_cpu(event->code),
  44                                     le32_to_cpu(event->value));
  45                         spin_lock_irqsave(&vi->lock, flags);
  46                         virtinput_queue_evtbuf(vi, event);
  47                 }
  48                 virtqueue_kick(vq);
  49         }
  50         spin_unlock_irqrestore(&vi->lock, flags);
  51 }
  52
  53 /*
  54  * On error we are losing the status update, which isn't critical as
  55  * this is typically used for stuff like keyboard leds.
  56  */
  57 static int virtinput_send_status(struct virtio_input *vi,
  58                                  u16 type, u16 code, s32 value)
  59 {
  60         struct virtio_input_event *stsbuf;
  61         struct scatterlist sg[1];
  62         unsigned long flags;
  63         int rc;
  64
  65         stsbuf = kzalloc(sizeof(*stsbuf), GFP_ATOMIC);
  66         if (!stsbuf)
  67                 return -ENOMEM;
  68
  69         stsbuf->type  = cpu_to_le16(type);
  70         stsbuf->code  = cpu_to_le16(code);
  71         stsbuf->value = cpu_to_le32(value);
  72         sg_init_one(sg, stsbuf, sizeof(*stsbuf));
  73
  74         spin_lock_irqsave(&vi->lock, flags);
  75         if (vi->ready) {
  76                 rc = virtqueue_add_outbuf(vi->sts, sg, 1, stsbuf, GFP_ATOMIC);
  77                 virtqueue_kick(vi->sts);
  78         } else {
  79                 rc = -ENODEV;
  80         }
  81         spin_unlock_irqrestore(&vi->lock, flags);
  82
  83         if (rc != 0)
  84                 kfree(stsbuf);
  85         return rc;
  86 }
  87
  88 static void virtinput_recv_status(struct virtqueue *vq)
  89 {
  90         struct virtio_input *vi = vq->vdev->priv;
  91         struct virtio_input_event *stsbuf;
  92         unsigned long flags;
  93         unsigned int len;
  94
  95         spin_lock_irqsave(&vi->lock, flags);
  96         while ((stsbuf = virtqueue_get_buf(vi->sts, &len)) != NULL)
  97                 kfree(stsbuf);
  98         spin_unlock_irqrestore(&vi->lock, flags);
  99 }
 100
 101 static int virtinput_status(struct input_dev *idev, unsigned int type,
 102                             unsigned int code, int value)
 103 {
 104         struct virtio_input *vi = input_get_drvdata(idev);
 105
 106         return virtinput_send_status(vi, type, code, value);
 107 }
 108
 109 static u8 virtinput_cfg_select(struct virtio_input *vi,
 110                                u8 select, u8 subsel)
 111 {
 112         u8 size;
 113
 114         virtio_cwrite(vi->vdev, struct virtio_input_config, select, &select);
 115         virtio_cwrite(vi->vdev, struct virtio_input_config, subsel, &subsel);
 116         virtio_cread(vi->vdev, struct virtio_input_config, size, &size);
 117         return size;
 118 }
 119
 120 static void virtinput_cfg_bits(struct virtio_input *vi, int select, int subsel,
 121                                unsigned long *bits, unsigned int bitcount)
 122 {
 123         unsigned int bit;
 124         u8 *virtio_bits;
 125         u8 bytes;
 126
 127         bytes = virtinput_cfg_select(vi, select, subsel);
 128         if (!bytes)
 129                 return;
 130         if (bitcount > bytes * 8)
 131                 bitcount = bytes * 8;
 132
 133         /*
 134          * Bitmap in virtio config space is a simple stream of bytes,
 135          * with the first byte carrying bits 0-7, second bits 8-15 and
 136          * so on.
 137          */
 138         virtio_bits = kzalloc(bytes, GFP_KERNEL);
 139         if (!virtio_bits)
 140                 return;
 141         virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config,
 142                                               u.bitmap),
 143                            virtio_bits, bytes);
 144         for (bit = 0; bit < bitcount; bit++) {
 145                 if (virtio_bits[bit / 8] & (1 << (bit % 8)))
 146                         __set_bit(bit, bits);
 147         }
 148         kfree(virtio_bits);
 149
 150         if (select == VIRTIO_INPUT_CFG_EV_BITS)
 151                 __set_bit(subsel, vi->idev->evbit);
 152 }
 153
 154 static void virtinput_cfg_abs(struct virtio_input *vi, int abs)
 155 {
 156         u32 mi, ma, re, fu, fl;
 157
 158         virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ABS_INFO, abs);
 159         virtio_cread(vi->vdev, struct virtio_input_config, u.abs.min, &mi);
 160         virtio_cread(vi->vdev, struct virtio_input_config, u.abs.max, &ma);
 161         virtio_cread(vi->vdev, struct virtio_input_config, u.abs.res, &re);
 162         virtio_cread(vi->vdev, struct virtio_input_config, u.abs.fuzz, &fu);
 163         virtio_cread(vi->vdev, struct virtio_input_config, u.abs.flat, &fl);
 164         input_set_abs_params(vi->idev, abs, mi, ma, fu, fl);
 165         input_abs_set_res(vi->idev, abs, re);
 166 }
 167
 168 static int virtinput_init_vqs(struct virtio_input *vi)
 169 {
 170         struct virtqueue *vqs[2];
 171         vq_callback_t *cbs[] = { virtinput_recv_events,
 172                                  virtinput_recv_status };
 173         static const char * const names[] = { "events", "status" };
 174         int err;
 175
 176         err = virtio_find_vqs(vi->vdev, 2, vqs, cbs, names, NULL);
 177         if (err)
 178                 return err;
 179         vi->evt = vqs[0];
 180         vi->sts = vqs[1];
 181
 182         return 0;
 183 }
 184
 185 static void virtinput_fill_evt(struct virtio_input *vi)
 186 {
 187         unsigned long flags;
 188         int i, size;
 189
 190         spin_lock_irqsave(&vi->lock, flags);
 191         size = virtqueue_get_vring_size(vi->evt);
 192         if (size > ARRAY_SIZE(vi->evts))
 193                 size = ARRAY_SIZE(vi->evts);
 194         for (i = 0; i < size; i++)
 195                 virtinput_queue_evtbuf(vi, &vi->evts[i]);
 196         virtqueue_kick(vi->evt);
 197         spin_unlock_irqrestore(&vi->lock, flags);
 198 }
 199
 200 static int virtinput_probe(struct virtio_device *vdev)
 201 {
 202         struct virtio_input *vi;
 203         unsigned long flags;
 204         size_t size;
 205         int abs, err;
 206
 207         if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
 208                 return -ENODEV;
 209
 210         vi = kzalloc(sizeof(*vi), GFP_KERNEL);
 211         if (!vi)
 212                 return -ENOMEM;
 213
 214         vdev->priv = vi;
 215         vi->vdev = vdev;
 216         spin_lock_init(&vi->lock);
 217
 218         err = virtinput_init_vqs(vi);
 219         if (err)
 220                 goto err_init_vq;
 221
 222         vi->idev = input_allocate_device();
 223         if (!vi->idev) {
 224                 err = -ENOMEM;
 225                 goto err_input_alloc;
 226         }
 227         input_set_drvdata(vi->idev, vi);
 228
 229         size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_NAME, 0);
 230         virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config,
 231                                               u.string),
 232                            vi->name, min(size, sizeof(vi->name)));
 233         size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_SERIAL, 0);
 234         virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config,
 235                                               u.string),
 236                            vi->serial, min(size, sizeof(vi->serial)));
 237         snprintf(vi->phys, sizeof(vi->phys),
 238                  "virtio%d/input0", vdev->index);
 239         vi->idev->name = vi->name;
 240         vi->idev->phys = vi->phys;
 241         vi->idev->uniq = vi->serial;
 242
 243         size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_DEVIDS, 0);
 244         if (size >= sizeof(struct virtio_input_devids)) {
 245                 virtio_cread(vi->vdev, struct virtio_input_config,
 246                              u.ids.bustype, &vi->idev->id.bustype);
 247                 virtio_cread(vi->vdev, struct virtio_input_config,
 248                              u.ids.vendor, &vi->idev->id.vendor);
 249                 virtio_cread(vi->vdev, struct virtio_input_config,
 250                              u.ids.product, &vi->idev->id.product);
 251                 virtio_cread(vi->vdev, struct virtio_input_config,
 252                              u.ids.version, &vi->idev->id.version);
 253         } else {
 254                 vi->idev->id.bustype = BUS_VIRTUAL;
 255         }
 256
 257         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_PROP_BITS, 0,
 258                            vi->idev->propbit, INPUT_PROP_CNT);
 259         size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_REP);
 260         if (size)
 261                 __set_bit(EV_REP, vi->idev->evbit);
 262
 263         vi->idev->dev.parent = &vdev->dev;
 264         vi->idev->event = virtinput_status;
 265
 266         /* device -> kernel */
 267         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_KEY,
 268                            vi->idev->keybit, KEY_CNT);
 269         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_REL,
 270                            vi->idev->relbit, REL_CNT);
 271         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_ABS,
 272                            vi->idev->absbit, ABS_CNT);
 273         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_MSC,
 274                            vi->idev->mscbit, MSC_CNT);
 275         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SW,
 276                            vi->idev->swbit,  SW_CNT);
 277
 278         /* kernel -> device */
 279         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_LED,
 280                            vi->idev->ledbit, LED_CNT);
 281         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SND,
 282                            vi->idev->sndbit, SND_CNT);
 283
 284         if (test_bit(EV_ABS, vi->idev->evbit)) {
 285                 for (abs = 0; abs < ABS_CNT; abs++) {
 286                         if (!test_bit(abs, vi->idev->absbit))
 287                                 continue;
 288                         virtinput_cfg_abs(vi, abs);
 289                 }
 290         }
 291
 292         virtio_device_ready(vdev);
 293         vi->ready = true;
 294         err = input_register_device(vi->idev);
 295         if (err)
 296                 goto err_input_register;
 297
 298         virtinput_fill_evt(vi);
 299         return 0;
 300
 301 err_input_register:
 302         spin_lock_irqsave(&vi->lock, flags);
 303         vi->ready = false;
 304         spin_unlock_irqrestore(&vi->lock, flags);
 305         input_free_device(vi->idev);
 306 err_input_alloc:
 307         vdev->config->del_vqs(vdev);
 308 err_init_vq:
 309         kfree(vi);
 310         return err;
 311 }
 312
 313 static void virtinput_remove(struct virtio_device *vdev)
 314 {
 315         struct virtio_input *vi = vdev->priv;
 316         void *buf;
 317         unsigned long flags;
 318
 319         spin_lock_irqsave(&vi->lock, flags);
 320         vi->ready = false;
 321         spin_unlock_irqrestore(&vi->lock, flags);
 322
 323         input_unregister_device(vi->idev);
 324         vdev->config->reset(vdev);
 325         while ((buf = virtqueue_detach_unused_buf(vi->sts)) != NULL)
 326                 kfree(buf);
 327         vdev->config->del_vqs(vdev);
 328         kfree(vi);
 329 }
 330
 331 #ifdef CONFIG_PM_SLEEP
 332 static int virtinput_freeze(struct virtio_device *vdev)
 333 {
 334         struct virtio_input *vi = vdev->priv;
 335         unsigned long flags;
 336
 337         spin_lock_irqsave(&vi->lock, flags);
 338         vi->ready = false;
 339         spin_unlock_irqrestore(&vi->lock, flags);
 340
 341         vdev->config->del_vqs(vdev);
 342         return 0;
 343 }
 344
 345 static int virtinput_restore(struct virtio_device *vdev)
 346 {
 347         struct virtio_input *vi = vdev->priv;
 348         int err;
 349
 350         err = virtinput_init_vqs(vi);
 351         if (err)
 352                 return err;
 353
 354         virtio_device_ready(vdev);
 355         vi->ready = true;
 356         virtinput_fill_evt(vi);
 357         return 0;
 358 }
 359 #endif
 360
 361 static unsigned int features[] = {
 362         /* none */
 363 };
 364 static struct virtio_device_id id_table[] = {
 365         { VIRTIO_ID_INPUT, VIRTIO_DEV_ANY_ID },
 366         { 0 },
 367 };
 368
 369 static struct virtio_driver virtio_input_driver = {
 370         .driver.name         = KBUILD_MODNAME,
 371         .driver.owner        = THIS_MODULE,
 372         .feature_table       = features,
 373         .feature_table_size  = ARRAY_SIZE(features),
 374         .id_table            = id_table,
 375         .probe               = virtinput_probe,
 376         .remove              = virtinput_remove,
 377 #ifdef CONFIG_PM_SLEEP
 378         .freeze              = virtinput_freeze,
 379         .restore             = virtinput_restore,
 380 #endif
 381 };
 382
 383 module_virtio_driver(virtio_input_driver);
 384 MODULE_DEVICE_TABLE(virtio, id_table);
 385
 386 MODULE_LICENSE("GPL");
 387 MODULE_DESCRIPTION("Virtio input device driver");
 388 MODULE_AUTHOR("Gerd Hoffmann <kraxel@redhat.com>");