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(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(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_info vqs_info[] = {
189 { "events", virtinput_recv_events },
190 { "status", virtinput_recv_status },
191 };
192 struct virtqueue *vqs[2];
193 int err;
194
195 err = virtio_find_vqs(vdev: vi->vdev, nvqs: 2, vqs, vqs_info, NULL);
196 if (err)
197 return err;
198 vi->evt = vqs[0];
199 vi->sts = vqs[1];
200
201 return 0;
202}
203
204static void virtinput_fill_evt(struct virtio_input *vi)
205{
206 unsigned long flags;
207 int i, size;
208
209 spin_lock_irqsave(&vi->lock, flags);
210 size = virtqueue_get_vring_size(vq: vi->evt);
211 if (size > ARRAY_SIZE(vi->evts))
212 size = ARRAY_SIZE(vi->evts);
213 for (i = 0; i < size; i++)
214 virtinput_queue_evtbuf(vi, evtbuf: &vi->evts[i]);
215 virtqueue_kick(vq: vi->evt);
216 spin_unlock_irqrestore(lock: &vi->lock, flags);
217}
218
219static int virtinput_probe(struct virtio_device *vdev)
220{
221 struct virtio_input *vi;
222 unsigned long flags;
223 size_t size;
224 int abs, err, nslots;
225
226 if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
227 return -ENODEV;
228
229 vi = kzalloc(sizeof(*vi), GFP_KERNEL);
230 if (!vi)
231 return -ENOMEM;
232
233 vdev->priv = vi;
234 vi->vdev = vdev;
235 spin_lock_init(&vi->lock);
236
237 err = virtinput_init_vqs(vi);
238 if (err)
239 goto err_init_vq;
240
241 vi->idev = input_allocate_device();
242 if (!vi->idev) {
243 err = -ENOMEM;
244 goto err_input_alloc;
245 }
246 input_set_drvdata(dev: vi->idev, data: vi);
247
248 size = virtinput_cfg_select(vi, select: VIRTIO_INPUT_CFG_ID_NAME, subsel: 0);
249 virtio_cread_bytes(vdev: vi->vdev, offsetof(struct virtio_input_config,
250 u.string),
251 buf: vi->name, min(size, sizeof(vi->name)));
252 size = virtinput_cfg_select(vi, select: VIRTIO_INPUT_CFG_ID_SERIAL, subsel: 0);
253 virtio_cread_bytes(vdev: vi->vdev, offsetof(struct virtio_input_config,
254 u.string),
255 buf: vi->serial, min(size, sizeof(vi->serial)));
256 snprintf(buf: vi->phys, size: sizeof(vi->phys),
257 fmt: "virtio%d/input0", vdev->index);
258 vi->idev->name = vi->name;
259 vi->idev->phys = vi->phys;
260 vi->idev->uniq = vi->serial;
261
262 size = virtinput_cfg_select(vi, select: VIRTIO_INPUT_CFG_ID_DEVIDS, subsel: 0);
263 if (size >= sizeof(struct virtio_input_devids)) {
264 virtio_cread_le(vi->vdev, struct virtio_input_config,
265 u.ids.bustype, &vi->idev->id.bustype);
266 virtio_cread_le(vi->vdev, struct virtio_input_config,
267 u.ids.vendor, &vi->idev->id.vendor);
268 virtio_cread_le(vi->vdev, struct virtio_input_config,
269 u.ids.product, &vi->idev->id.product);
270 virtio_cread_le(vi->vdev, struct virtio_input_config,
271 u.ids.version, &vi->idev->id.version);
272 } else {
273 vi->idev->id.bustype = BUS_VIRTUAL;
274 }
275
276 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_PROP_BITS, subsel: 0,
277 bits: vi->idev->propbit, INPUT_PROP_CNT);
278 size = virtinput_cfg_select(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_REP);
279 if (size)
280 __set_bit(EV_REP, vi->idev->evbit);
281
282 vi->idev->dev.parent = &vdev->dev;
283 vi->idev->event = virtinput_status;
284
285 /* device -> kernel */
286 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_KEY,
287 bits: vi->idev->keybit, KEY_CNT);
288 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_REL,
289 bits: vi->idev->relbit, REL_CNT);
290 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_ABS,
291 bits: vi->idev->absbit, ABS_CNT);
292 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_MSC,
293 bits: vi->idev->mscbit, MSC_CNT);
294 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_SW,
295 bits: vi->idev->swbit, SW_CNT);
296
297 /* kernel -> device */
298 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_LED,
299 bits: vi->idev->ledbit, LED_CNT);
300 virtinput_cfg_bits(vi, select: VIRTIO_INPUT_CFG_EV_BITS, EV_SND,
301 bits: vi->idev->sndbit, SND_CNT);
302
303 if (test_bit(EV_ABS, vi->idev->evbit)) {
304 for (abs = 0; abs < ABS_CNT; abs++) {
305 if (!test_bit(abs, vi->idev->absbit))
306 continue;
307 virtinput_cfg_abs(vi, abs);
308 }
309
310 if (test_bit(ABS_MT_SLOT, vi->idev->absbit)) {
311 nslots = input_abs_get_max(dev: vi->idev, ABS_MT_SLOT) + 1;
312 err = input_mt_init_slots(dev: vi->idev, num_slots: nslots, flags: 0);
313 if (err)
314 goto err_mt_init_slots;
315 }
316 }
317
318 virtio_device_ready(dev: vdev);
319 vi->ready = true;
320 err = input_register_device(vi->idev);
321 if (err)
322 goto err_input_register;
323
324 virtinput_fill_evt(vi);
325 return 0;
326
327err_input_register:
328 spin_lock_irqsave(&vi->lock, flags);
329 vi->ready = false;
330 spin_unlock_irqrestore(lock: &vi->lock, flags);
331err_mt_init_slots:
332 input_free_device(dev: vi->idev);
333err_input_alloc:
334 vdev->config->del_vqs(vdev);
335err_init_vq:
336 kfree(objp: vi);
337 return err;
338}
339
340static void virtinput_remove(struct virtio_device *vdev)
341{
342 struct virtio_input *vi = vdev->priv;
343 void *buf;
344 unsigned long flags;
345
346 spin_lock_irqsave(&vi->lock, flags);
347 vi->ready = false;
348 spin_unlock_irqrestore(lock: &vi->lock, flags);
349
350 input_unregister_device(vi->idev);
351 virtio_reset_device(dev: vdev);
352 while ((buf = virtqueue_detach_unused_buf(vq: vi->sts)) != NULL)
353 kfree(objp: buf);
354 vdev->config->del_vqs(vdev);
355 kfree(objp: vi);
356}
357
358#ifdef CONFIG_PM_SLEEP
359static int virtinput_freeze(struct virtio_device *vdev)
360{
361 struct virtio_input *vi = vdev->priv;
362 unsigned long flags;
363
364 spin_lock_irqsave(&vi->lock, flags);
365 vi->ready = false;
366 spin_unlock_irqrestore(lock: &vi->lock, flags);
367
368 vdev->config->del_vqs(vdev);
369 return 0;
370}
371
372static int virtinput_restore(struct virtio_device *vdev)
373{
374 struct virtio_input *vi = vdev->priv;
375 int err;
376
377 err = virtinput_init_vqs(vi);
378 if (err)
379 return err;
380
381 virtio_device_ready(dev: vdev);
382 vi->ready = true;
383 virtinput_fill_evt(vi);
384 return 0;
385}
386#endif
387
388static unsigned int features[] = {
389 /* none */
390};
391static const struct virtio_device_id id_table[] = {
392 { VIRTIO_ID_INPUT, VIRTIO_DEV_ANY_ID },
393 { 0 },
394};
395
396static struct virtio_driver virtio_input_driver = {
397 .driver.name = KBUILD_MODNAME,
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

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