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