drivers/virtio/virtio_input.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/module.h>
   3 #include <linux/virtio.h>
   4 #include <linux/virtio_config.h>
   5 #include <linux/input.h>
   6
   7 #include <uapi/linux/virtio_ids.h>
   8 #include <uapi/linux/virtio_input.h>
   9
  10 struct virtio_input {
  11         struct virtio_device       *vdev;
  12         struct input_dev           *idev;
  13         char                       name[64];
  14         char                       serial[64];
  15         char                       phys[64];
  16         struct virtqueue           *evt, *sts;
  17         struct virtio_input_event  evts[64];
  18         spinlock_t                 lock;
  19         bool                       ready;
  20 };
  21
  22 static void virtinput_queue_evtbuf(struct virtio_input *vi,
  23                                    struct virtio_input_event *evtbuf)
  24 {
  25         struct scatterlist sg[1];
  26
  27         sg_init_one(sg, evtbuf, sizeof(*evtbuf));
  28         virtqueue_add_inbuf(vi->evt, sg, 1, evtbuf, GFP_ATOMIC);
  29 }
  30
  31 static void virtinput_recv_events(struct virtqueue *vq)
  32 {
  33         struct virtio_input *vi = vq->vdev->priv;
  34         struct virtio_input_event *event;
  35         unsigned long flags;
  36         unsigned int len;
  37
  38         spin_lock_irqsave(&vi->lock, flags);
  39         if (vi->ready) {
  40                 while ((event = virtqueue_get_buf(vi->evt, &len)) != NULL) {
  41                         spin_unlock_irqrestore(&vi->lock, flags);
  42                         input_event(vi->idev,
  43                                     le16_to_cpu(event->type),
  44                                     le16_to_cpu(event->code),
  45                                     le32_to_cpu(event->value));
  46                         spin_lock_irqsave(&vi->lock, flags);
  47                         virtinput_queue_evtbuf(vi, event);
  48                 }
  49                 virtqueue_kick(vq);
  50         }
  51         spin_unlock_irqrestore(&vi->lock, flags);
  52 }
  53
  54 /*
  55  * On error we are losing the status update, which isn't critical as
  56  * this is typically used for stuff like keyboard leds.
  57  */
  58 static int virtinput_send_status(struct virtio_input *vi,
  59                                  u16 type, u16 code, s32 value)
  60 {
  61         struct virtio_input_event *stsbuf;
  62         struct scatterlist sg[1];
  63         unsigned long flags;
  64         int rc;
  65
  66         stsbuf = kzalloc(sizeof(*stsbuf), GFP_ATOMIC);
  67         if (!stsbuf)
  68                 return -ENOMEM;
  69
  70         stsbuf->type  = cpu_to_le16(type);
  71         stsbuf->code  = cpu_to_le16(code);
  72         stsbuf->value = cpu_to_le32(value);
  73         sg_init_one(sg, stsbuf, sizeof(*stsbuf));
  74
  75         spin_lock_irqsave(&vi->lock, flags);
  76         if (vi->ready) {
  77                 rc = virtqueue_add_outbuf(vi->sts, sg, 1, stsbuf, GFP_ATOMIC);
  78                 virtqueue_kick(vi->sts);
  79         } else {
  80                 rc = -ENODEV;
  81         }
  82         spin_unlock_irqrestore(&vi->lock, flags);
  83
  84         if (rc != 0)
  85                 kfree(stsbuf);
  86         return rc;
  87 }
  88
  89 static void virtinput_recv_status(struct virtqueue *vq)
  90 {
  91         struct virtio_input *vi = vq->vdev->priv;
  92         struct virtio_input_event *stsbuf;
  93         unsigned long flags;
  94         unsigned int len;
  95
  96         spin_lock_irqsave(&vi->lock, flags);
  97         while ((stsbuf = virtqueue_get_buf(vi->sts, &len)) != NULL)
  98                 kfree(stsbuf);
  99         spin_unlock_irqrestore(&vi->lock, flags);
 100 }
 101
 102 static int virtinput_status(struct input_dev *idev, unsigned int type,
 103                             unsigned int code, int value)
 104 {
 105         struct virtio_input *vi = input_get_drvdata(idev);
 106
 107         return virtinput_send_status(vi, type, code, value);
 108 }
 109
 110 static u8 virtinput_cfg_select(struct virtio_input *vi,
 111                                u8 select, u8 subsel)
 112 {
 113         u8 size;
 114
 115         virtio_cwrite(vi->vdev, struct virtio_input_config, select, &select);
 116         virtio_cwrite(vi->vdev, struct virtio_input_config, subsel, &subsel);
 117         virtio_cread(vi->vdev, struct virtio_input_config, size, &size);
 118         return size;
 119 }
 120
 121 static void virtinput_cfg_bits(struct virtio_input *vi, int select, int subsel,
 122                                unsigned long *bits, unsigned int bitcount)
 123 {
 124         unsigned int bit;
 125         u8 *virtio_bits;
 126         u8 bytes;
 127
 128         bytes = virtinput_cfg_select(vi, select, subsel);
 129         if (!bytes)
 130                 return;
 131         if (bitcount > bytes * 8)
 132                 bitcount = bytes * 8;
 133
 134         /*
 135          * Bitmap in virtio config space is a simple stream of bytes,
 136          * with the first byte carrying bits 0-7, second bits 8-15 and
 137          * so on.
 138          */
 139         virtio_bits = kzalloc(bytes, GFP_KERNEL);
 140         if (!virtio_bits)
 141                 return;
 142         virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config,
 143                                               u.bitmap),
 144                            virtio_bits, bytes);
 145         for (bit = 0; bit < bitcount; bit++) {
 146                 if (virtio_bits[bit / 8] & (1 << (bit % 8)))
 147                         __set_bit(bit, bits);
 148         }
 149         kfree(virtio_bits);
 150
 151         if (select == VIRTIO_INPUT_CFG_EV_BITS)
 152                 __set_bit(subsel, vi->idev->evbit);
 153 }
 154
 155 static void virtinput_cfg_abs(struct virtio_input *vi, int abs)
 156 {
 157         u32 mi, ma, re, fu, fl;
 158
 159         virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ABS_INFO, abs);
 160         virtio_cread(vi->vdev, struct virtio_input_config, u.abs.min, &mi);
 161         virtio_cread(vi->vdev, struct virtio_input_config, u.abs.max, &ma);
 162         virtio_cread(vi->vdev, struct virtio_input_config, u.abs.res, &re);
 163         virtio_cread(vi->vdev, struct virtio_input_config, u.abs.fuzz, &fu);
 164         virtio_cread(vi->vdev, struct virtio_input_config, u.abs.flat, &fl);
 165         input_set_abs_params(vi->idev, abs, mi, ma, fu, fl);
 166         input_abs_set_res(vi->idev, abs, re);
 167 }
 168
 169 static int virtinput_init_vqs(struct virtio_input *vi)
 170 {
 171         struct virtqueue *vqs[2];
 172         vq_callback_t *cbs[] = { virtinput_recv_events,
 173                                  virtinput_recv_status };
 174         static const char * const names[] = { "events", "status" };
 175         int err;
 176
 177         err = virtio_find_vqs(vi->vdev, 2, vqs, cbs, names, NULL);
 178         if (err)
 179                 return err;
 180         vi->evt = vqs[0];
 181         vi->sts = vqs[1];
 182
 183         return 0;
 184 }
 185
 186 static void virtinput_fill_evt(struct virtio_input *vi)
 187 {
 188         unsigned long flags;
 189         int i, size;
 190
 191         spin_lock_irqsave(&vi->lock, flags);
 192         size = virtqueue_get_vring_size(vi->evt);
 193         if (size > ARRAY_SIZE(vi->evts))
 194                 size = ARRAY_SIZE(vi->evts);
 195         for (i = 0; i < size; i++)
 196                 virtinput_queue_evtbuf(vi, &vi->evts[i]);
 197         virtqueue_kick(vi->evt);
 198         spin_unlock_irqrestore(&vi->lock, flags);
 199 }
 200
 201 static int virtinput_probe(struct virtio_device *vdev)
 202 {
 203         struct virtio_input *vi;
 204         unsigned long flags;
 205         size_t size;
 206         int abs, err;
 207
 208         if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
 209                 return -ENODEV;
 210
 211         vi = kzalloc(sizeof(*vi), GFP_KERNEL);
 212         if (!vi)
 213                 return -ENOMEM;
 214
 215         vdev->priv = vi;
 216         vi->vdev = vdev;
 217         spin_lock_init(&vi->lock);
 218
 219         err = virtinput_init_vqs(vi);
 220         if (err)
 221                 goto err_init_vq;
 222
 223         vi->idev = input_allocate_device();
 224         if (!vi->idev) {
 225                 err = -ENOMEM;
 226                 goto err_input_alloc;
 227         }
 228         input_set_drvdata(vi->idev, vi);
 229
 230         size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_NAME, 0);
 231         virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config,
 232                                               u.string),
 233                            vi->name, min(size, sizeof(vi->name)));
 234         size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_SERIAL, 0);
 235         virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config,
 236                                               u.string),
 237                            vi->serial, min(size, sizeof(vi->serial)));
 238         snprintf(vi->phys, sizeof(vi->phys),
 239                  "virtio%d/input0", vdev->index);
 240         vi->idev->name = vi->name;
 241         vi->idev->phys = vi->phys;
 242         vi->idev->uniq = vi->serial;
 243
 244         size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_DEVIDS, 0);
 245         if (size >= sizeof(struct virtio_input_devids)) {
 246                 virtio_cread(vi->vdev, struct virtio_input_config,
 247                              u.ids.bustype, &vi->idev->id.bustype);
 248                 virtio_cread(vi->vdev, struct virtio_input_config,
 249                              u.ids.vendor, &vi->idev->id.vendor);
 250                 virtio_cread(vi->vdev, struct virtio_input_config,
 251                              u.ids.product, &vi->idev->id.product);
 252                 virtio_cread(vi->vdev, struct virtio_input_config,
 253                              u.ids.version, &vi->idev->id.version);
 254         } else {
 255                 vi->idev->id.bustype = BUS_VIRTUAL;
 256         }
 257
 258         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_PROP_BITS, 0,
 259                            vi->idev->propbit, INPUT_PROP_CNT);
 260         size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_REP);
 261         if (size)
 262                 __set_bit(EV_REP, vi->idev->evbit);
 263
 264         vi->idev->dev.parent = &vdev->dev;
 265         vi->idev->event = virtinput_status;
 266
 267         /* device -> kernel */
 268         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_KEY,
 269                            vi->idev->keybit, KEY_CNT);
 270         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_REL,
 271                            vi->idev->relbit, REL_CNT);
 272         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_ABS,
 273                            vi->idev->absbit, ABS_CNT);
 274         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_MSC,
 275                            vi->idev->mscbit, MSC_CNT);
 276         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SW,
 277                            vi->idev->swbit,  SW_CNT);
 278
 279         /* kernel -> device */
 280         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_LED,
 281                            vi->idev->ledbit, LED_CNT);
 282         virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SND,
 283                            vi->idev->sndbit, SND_CNT);
 284
 285         if (test_bit(EV_ABS, vi->idev->evbit)) {
 286                 for (abs = 0; abs < ABS_CNT; abs++) {
 287                         if (!test_bit(abs, vi->idev->absbit))
 288                                 continue;
 289                         virtinput_cfg_abs(vi, abs);
 290                 }
 291         }
 292
 293         virtio_device_ready(vdev);
 294         vi->ready = true;
 295         err = input_register_device(vi->idev);
 296         if (err)
 297                 goto err_input_register;
 298
 299         virtinput_fill_evt(vi);
 300         return 0;
 301
 302 err_input_register:
 303         spin_lock_irqsave(&vi->lock, flags);
 304         vi->ready = false;
 305         spin_unlock_irqrestore(&vi->lock, flags);
 306         input_free_device(vi->idev);
 307 err_input_alloc:
 308         vdev->config->del_vqs(vdev);
 309 err_init_vq:
 310         kfree(vi);
 311         return err;
 312 }
 313
 314 static void virtinput_remove(struct virtio_device *vdev)
 315 {
 316         struct virtio_input *vi = vdev->priv;
 317         void *buf;
 318         unsigned long flags;
 319
 320         spin_lock_irqsave(&vi->lock, flags);
 321         vi->ready = false;
 322         spin_unlock_irqrestore(&vi->lock, flags);
 323
 324         input_unregister_device(vi->idev);
 325         vdev->config->reset(vdev);
 326         while ((buf = virtqueue_detach_unused_buf(vi->sts)) != NULL)
 327                 kfree(buf);
 328         vdev->config->del_vqs(vdev);
 329         kfree(vi);
 330 }
 331
 332 #ifdef CONFIG_PM_SLEEP
 333 static int virtinput_freeze(struct virtio_device *vdev)
 334 {
 335         struct virtio_input *vi = vdev->priv;
 336         unsigned long flags;
 337
 338         spin_lock_irqsave(&vi->lock, flags);
 339         vi->ready = false;
 340         spin_unlock_irqrestore(&vi->lock, flags);
 341
 342         vdev->config->del_vqs(vdev);
 343         return 0;
 344 }
 345
 346 static int virtinput_restore(struct virtio_device *vdev)
 347 {
 348         struct virtio_input *vi = vdev->priv;
 349         int err;
 350
 351         err = virtinput_init_vqs(vi);
 352         if (err)
 353                 return err;
 354
 355         virtio_device_ready(vdev);
 356         vi->ready = true;
 357         virtinput_fill_evt(vi);
 358         return 0;
 359 }
 360 #endif
 361
 362 static unsigned int features[] = {
 363         /* none */
 364 };
 365 static struct virtio_device_id id_table[] = {
 366         { VIRTIO_ID_INPUT, VIRTIO_DEV_ANY_ID },
 367         { 0 },
 368 };
 369
 370 static struct virtio_driver virtio_input_driver = {
 371         .driver.name         = KBUILD_MODNAME,
 372         .driver.owner        = THIS_MODULE,
 373         .feature_table       = features,
 374         .feature_table_size  = ARRAY_SIZE(features),
 375         .id_table            = id_table,
 376         .probe               = virtinput_probe,
 377         .remove              = virtinput_remove,
 378 #ifdef CONFIG_PM_SLEEP
 379         .freeze              = virtinput_freeze,
 380         .restore             = virtinput_restore,
 381 #endif
 382 };
 383
 384 module_virtio_driver(virtio_input_driver);
 385 MODULE_DEVICE_TABLE(virtio, id_table);
 386
 387 MODULE_LICENSE("GPL");
 388 MODULE_DESCRIPTION("Virtio input device driver");
 389 MODULE_AUTHOR("Gerd Hoffmann <kraxel@redhat.com>");