linux/drivers/virtio/virtio_input.c
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   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
   9struct 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
  21static 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
  30static 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 */
  57static 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
  88static 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
 101static 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
 109static 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
 120static 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
 154static 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
 168static 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 = vi->vdev->config->find_vqs(vi->vdev, 2, vqs, cbs, names);
 177        if (err)
 178                return err;
 179        vi->evt = vqs[0];
 180        vi->sts = vqs[1];
 181
 182        return 0;
 183}
 184
 185static 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
 200static 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
 301err_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);
 306err_input_alloc:
 307        vdev->config->del_vqs(vdev);
 308err_init_vq:
 309        kfree(vi);
 310        return err;
 311}
 312
 313static 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
 332static 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
 345static 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
 361static unsigned int features[] = {
 362        /* none */
 363};
 364static struct virtio_device_id id_table[] = {
 365        { VIRTIO_ID_INPUT, VIRTIO_DEV_ANY_ID },
 366        { 0 },
 367};
 368
 369static 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
 383module_virtio_driver(virtio_input_driver);
 384MODULE_DEVICE_TABLE(virtio, id_table);
 385
 386MODULE_LICENSE("GPL");
 387MODULE_DESCRIPTION("Virtio input device driver");
 388MODULE_AUTHOR("Gerd Hoffmann <kraxel@redhat.com>");
 389