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#include <linux/input/mt.h>
11
12struct virtio_input {
13 struct virtio_device *vdev;
14 struct input_dev *idev;
15 char name[64];
16 char serial[64];
17 char phys[64];
18 struct virtqueue *evt, *sts;
19 struct virtio_input_event evts[64];
20 spinlock_t lock;
21 bool ready;
22};
23
24static void virtinput_queue_evtbuf(struct virtio_input *vi,
25 struct virtio_input_event *evtbuf)
26{
27 struct scatterlist sg[1];
28
29 sg_init_one(sg, evtbuf, sizeof(*evtbuf));
30 virtqueue_add_inbuf(vq: vi->evt, sg, num: 1, data: evtbuf, GFP_ATOMIC);
31}
32
33static void virtinput_recv_events(struct virtqueue *vq)
34{
35 struct virtio_input *vi = vq->vdev->priv;
36 struct virtio_input_event *event;
37 unsigned long flags;
38 unsigned int len;
39
40 spin_lock_irqsave(&vi->lock, flags);
41 if (vi->ready) {
42 while ((event = virtqueue_get_buf(vq: vi->evt, len: &len)) != NULL) {
43 spin_unlock_irqrestore(lock: &vi->lock, flags);
44 input_event(dev: vi->idev,
45 le16_to_cpu(event->type),
46 le16_to_cpu(event->code),
47 le32_to_cpu(event->value));
48 spin_lock_irqsave(&vi->lock, flags);
49 virtinput_queue_evtbuf(vi, evtbuf: event);
50 }
51 virtqueue_kick(vq);
52 }
53 spin_unlock_irqrestore(lock: &vi->lock, flags);
54}
55
56/*
57 * On error we are losing the status update, which isn't critical as
58 * this is typically used for stuff like keyboard leds.
59 */
60static int virtinput_send_status(struct virtio_input *vi,
61 u16 type, u16 code, s32 value)
62{
63 struct virtio_input_event *stsbuf;
64 struct scatterlist sg[1];
65 unsigned long flags;
66 int rc;
67
68 /*
69 * Since 29cc309d8bf1 (HID: hid-multitouch: forward MSC_TIMESTAMP),
70 * EV_MSC/MSC_TIMESTAMP is added to each before EV_SYN event.
71 * EV_MSC is configured as INPUT_PASS_TO_ALL.
72 * In case of touch device:
73 * BE pass EV_MSC/MSC_TIMESTAMP to FE on receiving event from evdev.
74 * FE pass EV_MSC/MSC_TIMESTAMP back to BE.
75 * BE writes EV_MSC/MSC_TIMESTAMP to evdev due to INPUT_PASS_TO_ALL.
76 * BE receives extra EV_MSC/MSC_TIMESTAMP and pass to FE.
77 * >>> Each new frame becomes larger and larger.
78 * Disable EV_MSC/MSC_TIMESTAMP forwarding for MT.
79 */
80 if (vi->idev->mt && type == EV_MSC && code == MSC_TIMESTAMP)
81 return 0;
82
83 stsbuf = kzalloc(size: sizeof(*stsbuf), GFP_ATOMIC);
84 if (!stsbuf)
85 return -ENOMEM;
86
87 stsbuf->type = cpu_to_le16(type);
88 stsbuf->code = cpu_to_le16(code);
89 stsbuf->value = cpu_to_le32(value);
90 sg_init_one(sg, stsbuf, sizeof(*stsbuf));
91
92 spin_lock_irqsave(&vi->lock, flags);
93 if (vi->ready) {
94 rc = virtqueue_add_outbuf(vq: vi->sts, sg, num: 1, data: stsbuf, GFP_ATOMIC);
95 virtqueue_kick(vq: vi->sts);
96 } else {
97 rc = -ENODEV;
98 }
99 spin_unlock_irqrestore(lock: &vi->lock, flags);
100
101 if (rc != 0)
102 kfree(objp: stsbuf);
103 return rc;
104}
105
106static void virtinput_recv_status(struct virtqueue *vq)
107{
108 struct virtio_input *vi = vq->vdev->priv;
109 struct virtio_input_event *stsbuf;
110 unsigned long flags;
111 unsigned int len;
112
113 spin_lock_irqsave(&vi->lock, flags);
114 while ((stsbuf = virtqueue_get_buf(vq: vi->sts, len: &len)) != NULL)
115 kfree(objp: stsbuf);
116 spin_unlock_irqrestore(lock: &vi->lock, flags);
117}
118
119static int virtinput_status(struct input_dev *idev, unsigned int type,
120 unsigned int code, int value)
121{
122 struct virtio_input *vi = input_get_drvdata(dev: idev);
123
124 return virtinput_send_status(vi, type, code, value);
125}
126
127static u8 virtinput_cfg_select(struct virtio_input *vi,
128 u8 select, u8 subsel)
129{
130 u8 size;
131
132 virtio_cwrite_le(vi->vdev, struct virtio_input_config, select, &select);
133 virtio_cwrite_le(vi->vdev, struct virtio_input_config, subsel, &subsel);
134 virtio_cread_le(vi->vdev, struct virtio_input_config, size, &size);
135 return size;
136}
137
138static void virtinput_cfg_bits(struct virtio_input *vi, int select, int subsel,
139 unsigned long *bits, unsigned int bitcount)
140{
141 unsigned int bit;
142 u8 *virtio_bits;
143 u8 bytes;
144
145 bytes = virtinput_cfg_select(vi, select, subsel);
146 if (!bytes)
147 return;
148 if (bitcount > bytes * 8)
149 bitcount = bytes * 8;
150
151 /*
152 * Bitmap in virtio config space is a simple stream of bytes,
153 * with the first byte carrying bits 0-7, second bits 8-15 and
154 * so on.
155 */
156 virtio_bits = kzalloc(size: bytes, GFP_KERNEL);
157 if (!virtio_bits)
158 return;
159 virtio_cread_bytes(vdev: vi->vdev, offsetof(struct virtio_input_config,
160 u.bitmap),
161 buf: virtio_bits, len: bytes);
162 for (bit = 0; bit < bitcount; bit++) {
163 if (virtio_bits[bit / 8] & (1 << (bit % 8)))
164 __set_bit(bit, bits);
165 }
166 kfree(objp: virtio_bits);
167
168 if (select == VIRTIO_INPUT_CFG_EV_BITS)
169 __set_bit(subsel, vi->idev->evbit);
170}
171
172static void virtinput_cfg_abs(struct virtio_input *vi, int abs)
173{
174 u32 mi, ma, re, fu, fl;
175
176 virtinput_cfg_select(vi, select: VIRTIO_INPUT_CFG_ABS_INFO, subsel: abs);
177 virtio_cread_le(vi->vdev, struct virtio_input_config, u.abs.min, &mi);
178 virtio_cread_le(vi->vdev, struct virtio_input_config, u.abs.max, &ma);
179 virtio_cread_le(vi->vdev, struct virtio_input_config, u.abs.res, &re);
180 virtio_cread_le(vi->vdev, struct virtio_input_config, u.abs.fuzz, &fu);
181 virtio_cread_le(vi->vdev, struct virtio_input_config, u.abs.flat, &fl);
182 input_set_abs_params(dev: vi->idev, axis: abs, min: mi, max: ma, fuzz: fu, flat: fl);
183 input_abs_set_res(dev: vi->idev, axis: abs, val: re);
184}
185
186static int virtinput_init_vqs(struct virtio_input *vi)
187{
188 struct virtqueue *vqs[2];
189 vq_callback_t *cbs[] = { virtinput_recv_events,
190 virtinput_recv_status };
191 static const char * const names[] = { "events", "status" };
192 int err;
193
194 err = virtio_find_vqs(vdev: vi->vdev, nvqs: 2, vqs, callbacks: cbs, names, NULL);
195 if (err)
196 return err;
197 vi->evt = vqs[0];
198 vi->sts = vqs[1];
199
200 return 0;
201}
202
203static void virtinput_fill_evt(struct virtio_input *vi)
204{
205 unsigned long flags;
206 int i, size;
207
208 spin_lock_irqsave(&vi->lock, flags);
209 size = virtqueue_get_vring_size(vq: vi->evt);
210 if (size > ARRAY_SIZE(vi->evts))
211 size = ARRAY_SIZE(vi->evts);
212 for (i = 0; i < size; i++)
213 virtinput_queue_evtbuf(vi, evtbuf: &vi->evts[i]);
214 virtqueue_kick(vq: vi->evt);
215 spin_unlock_irqrestore(lock: &vi->lock, flags);
216}
217
218static int virtinput_probe(struct virtio_device *vdev)
219{
220 struct virtio_input *vi;
221 unsigned long flags;
222 size_t size;
223 int abs, err, nslots;
224
225 if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
226 return -ENODEV;
227
228 vi = kzalloc(size: sizeof(*vi), GFP_KERNEL);
229 if (!vi)
230 return -ENOMEM;
231
232 vdev->priv = vi;
233 vi->vdev = vdev;
234 spin_lock_init(&vi->lock);
235
236 err = virtinput_init_vqs(vi);
237 if (err)
238 goto err_init_vq;
239
240 vi->idev = input_allocate_device();
241 if (!vi->idev) {
242 err = -ENOMEM;
243 goto err_input_alloc;
244 }
245 input_set_drvdata(dev: vi->idev, data: vi);
246
247 size = virtinput_cfg_select(vi, select: VIRTIO_INPUT_CFG_ID_NAME, subsel: 0);
248 virtio_cread_bytes(vdev: vi->vdev, offsetof(struct virtio_input_config,
249 u.string),
250 buf: vi->name, min(size, sizeof(vi->name)));
251 size = virtinput_cfg_select(vi, select: VIRTIO_INPUT_CFG_ID_SERIAL, subsel: 0);
252 virtio_cread_bytes(vdev: vi->vdev, offsetof(struct virtio_input_config,
253 u.string),
254 buf: vi->serial, min(size, sizeof(vi->serial)));
255 snprintf(buf: vi->phys, size: sizeof(vi->phys),
256 fmt: "virtio%d/input0", vdev->index);
257 vi->idev->name = vi->name;
258 vi->idev->phys = vi->phys;
259 vi->idev->uniq = vi->serial;
260
261 size = virtinput_cfg_select(vi, select: VIRTIO_INPUT_CFG_ID_DEVIDS, subsel: 0);
262 if (size >= sizeof(struct virtio_input_devids)) {
263 virtio_cread_le(vi->vdev, struct virtio_input_config,
264 u.ids.bustype, &vi->idev->id.bustype);
265 virtio_cread_le(vi->vdev, struct virtio_input_config,
266 u.ids.vendor, &vi->idev->id.vendor);
267 virtio_cread_le(vi->vdev, struct virtio_input_config,
268 u.ids.product, &vi->idev->id.product);
269 virtio_cread_le(vi->vdev, struct virtio_input_config,
270 u.ids.version, &vi->idev->id.version);
271 } else {
272 vi->idev->id.bustype = BUS_VIRTUAL;
273 }
274
275 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_PROP_BITS, subsel: 0,
276 bits: vi->idev->propbit, INPUT_PROP_CNT);
277 size = virtinput_cfg_select(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_REP);
278 if (size)
279 __set_bit(EV_REP, vi->idev->evbit);
280
281 vi->idev->dev.parent = &vdev->dev;
282 vi->idev->event = virtinput_status;
283
284 /* device -> kernel */
285 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_KEY,
286 bits: vi->idev->keybit, KEY_CNT);
287 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_REL,
288 bits: vi->idev->relbit, REL_CNT);
289 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_ABS,
290 bits: vi->idev->absbit, ABS_CNT);
291 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_MSC,
292 bits: vi->idev->mscbit, MSC_CNT);
293 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_SW,
294 bits: vi->idev->swbit, SW_CNT);
295
296 /* kernel -> device */
297 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_LED,
298 bits: vi->idev->ledbit, LED_CNT);
299 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_SND,
300 bits: vi->idev->sndbit, SND_CNT);
301
302 if (test_bit(EV_ABS, vi->idev->evbit)) {
303 for (abs = 0; abs < ABS_CNT; abs++) {
304 if (!test_bit(abs, vi->idev->absbit))
305 continue;
306 virtinput_cfg_abs(vi, abs);
307 }
308
309 if (test_bit(ABS_MT_SLOT, vi->idev->absbit)) {
310 nslots = input_abs_get_max(dev: vi->idev, ABS_MT_SLOT) + 1;
311 err = input_mt_init_slots(dev: vi->idev, num_slots: nslots, flags: 0);
312 if (err)
313 goto err_mt_init_slots;
314 }
315 }
316
317 virtio_device_ready(dev: vdev);
318 vi->ready = true;
319 err = input_register_device(vi->idev);
320 if (err)
321 goto err_input_register;
322
323 virtinput_fill_evt(vi);
324 return 0;
325
326err_input_register:
327 spin_lock_irqsave(&vi->lock, flags);
328 vi->ready = false;
329 spin_unlock_irqrestore(lock: &vi->lock, flags);
330err_mt_init_slots:
331 input_free_device(dev: vi->idev);
332err_input_alloc:
333 vdev->config->del_vqs(vdev);
334err_init_vq:
335 kfree(objp: vi);
336 return err;
337}
338
339static void virtinput_remove(struct virtio_device *vdev)
340{
341 struct virtio_input *vi = vdev->priv;
342 void *buf;
343 unsigned long flags;
344
345 spin_lock_irqsave(&vi->lock, flags);
346 vi->ready = false;
347 spin_unlock_irqrestore(lock: &vi->lock, flags);
348
349 input_unregister_device(vi->idev);
350 virtio_reset_device(dev: vdev);
351 while ((buf = virtqueue_detach_unused_buf(vq: vi->sts)) != NULL)
352 kfree(objp: buf);
353 vdev->config->del_vqs(vdev);
354 kfree(objp: vi);
355}
356
357#ifdef CONFIG_PM_SLEEP
358static int virtinput_freeze(struct virtio_device *vdev)
359{
360 struct virtio_input *vi = vdev->priv;
361 unsigned long flags;
362
363 spin_lock_irqsave(&vi->lock, flags);
364 vi->ready = false;
365 spin_unlock_irqrestore(lock: &vi->lock, flags);
366
367 vdev->config->del_vqs(vdev);
368 return 0;
369}
370
371static int virtinput_restore(struct virtio_device *vdev)
372{
373 struct virtio_input *vi = vdev->priv;
374 int err;
375
376 err = virtinput_init_vqs(vi);
377 if (err)
378 return err;
379
380 virtio_device_ready(dev: vdev);
381 vi->ready = true;
382 virtinput_fill_evt(vi);
383 return 0;
384}
385#endif
386
387static unsigned int features[] = {
388 /* none */
389};
390static const struct virtio_device_id id_table[] = {
391 { VIRTIO_ID_INPUT, VIRTIO_DEV_ANY_ID },
392 { 0 },
393};
394
395static struct virtio_driver virtio_input_driver = {
396 .driver.name = KBUILD_MODNAME,
397 .driver.owner = THIS_MODULE,
398 .feature_table = features,
399 .feature_table_size = ARRAY_SIZE(features),
400 .id_table = id_table,
401 .probe = virtinput_probe,
402 .remove = virtinput_remove,
403#ifdef CONFIG_PM_SLEEP
404 .freeze = virtinput_freeze,
405 .restore = virtinput_restore,
406#endif
407};
408
409module_virtio_driver(virtio_input_driver);
410MODULE_DEVICE_TABLE(virtio, id_table);
411
412MODULE_LICENSE("GPL");
413MODULE_DESCRIPTION("Virtio input device driver");
414MODULE_AUTHOR("Gerd Hoffmann <kraxel@redhat.com>");
415

source code of linux/drivers/virtio/virtio_input.c