linux/drivers/virtio/virtio_input.c
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   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
  10struct 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
  22static 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
  31static 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 */
  58static 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
  89static 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
 102static 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
 110static 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
 121static 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
 155static 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
 169static 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
 186static 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
 201static 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
 302err_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);
 307err_input_alloc:
 308        vdev->config->del_vqs(vdev);
 309err_init_vq:
 310        kfree(vi);
 311        return err;
 312}
 313
 314static 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
 333static 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
 346static 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
 362static unsigned int features[] = {
 363        /* none */
 364};
 365static struct virtio_device_id id_table[] = {
 366        { VIRTIO_ID_INPUT, VIRTIO_DEV_ANY_ID },
 367        { 0 },
 368};
 369
 370static 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
 384module_virtio_driver(virtio_input_driver);
 385MODULE_DEVICE_TABLE(virtio, id_table);
 386
 387MODULE_LICENSE("GPL");
 388MODULE_DESCRIPTION("Virtio input device driver");
 389MODULE_AUTHOR("Gerd Hoffmann <kraxel@redhat.com>");
 390