xref: /openbmc/linux/drivers/virtio/virtio_input.c (revision d9679d00)
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 
12 struct 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 
virtinput_queue_evtbuf(struct virtio_input * vi,struct virtio_input_event * evtbuf)24 static 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(vi->evt, sg, 1, evtbuf, GFP_ATOMIC);
31 }
32 
virtinput_recv_events(struct virtqueue * vq)33 static 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(vi->evt, &len)) != NULL) {
43 			spin_unlock_irqrestore(&vi->lock, flags);
44 			input_event(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, event);
50 		}
51 		virtqueue_kick(vq);
52 	}
53 	spin_unlock_irqrestore(&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  */
virtinput_send_status(struct virtio_input * vi,u16 type,u16 code,s32 value)60 static 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(vi->sts, sg, 1, stsbuf, GFP_ATOMIC);
95 		virtqueue_kick(vi->sts);
96 	} else {
97 		rc = -ENODEV;
98 	}
99 	spin_unlock_irqrestore(&vi->lock, flags);
100 
101 	if (rc != 0)
102 		kfree(stsbuf);
103 	return rc;
104 }
105 
virtinput_recv_status(struct virtqueue * vq)106 static 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(vi->sts, &len)) != NULL)
115 		kfree(stsbuf);
116 	spin_unlock_irqrestore(&vi->lock, flags);
117 }
118 
virtinput_status(struct input_dev * idev,unsigned int type,unsigned int code,int value)119 static 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(idev);
123 
124 	return virtinput_send_status(vi, type, code, value);
125 }
126 
virtinput_cfg_select(struct virtio_input * vi,u8 select,u8 subsel)127 static 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 
virtinput_cfg_bits(struct virtio_input * vi,int select,int subsel,unsigned long * bits,unsigned int bitcount)138 static 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(vi->vdev, offsetof(struct virtio_input_config,
160 					      u.bitmap),
161 			   virtio_bits, 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(virtio_bits);
167 
168 	if (select == VIRTIO_INPUT_CFG_EV_BITS)
169 		__set_bit(subsel, vi->idev->evbit);
170 }
171 
virtinput_cfg_abs(struct virtio_input * vi,int abs)172 static void virtinput_cfg_abs(struct virtio_input *vi, int abs)
173 {
174 	u32 mi, ma, re, fu, fl;
175 
176 	virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ABS_INFO, 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(vi->idev, abs, mi, ma, fu, fl);
183 	input_abs_set_res(vi->idev, abs, re);
184 }
185 
virtinput_init_vqs(struct virtio_input * vi)186 static 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(vi->vdev, 2, vqs, 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 
virtinput_fill_evt(struct virtio_input * vi)203 static 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(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, &vi->evts[i]);
214 	virtqueue_kick(vi->evt);
215 	spin_unlock_irqrestore(&vi->lock, flags);
216 }
217 
virtinput_probe(struct virtio_device * vdev)218 static 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(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(vi->idev, vi);
246 
247 	size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_NAME, 0);
248 	virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config,
249 					      u.string),
250 			   vi->name, min(size, sizeof(vi->name)));
251 	size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_SERIAL, 0);
252 	virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config,
253 					      u.string),
254 			   vi->serial, min(size, sizeof(vi->serial)));
255 	snprintf(vi->phys, sizeof(vi->phys),
256 		 "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, VIRTIO_INPUT_CFG_ID_DEVIDS, 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, VIRTIO_INPUT_CFG_PROP_BITS, 0,
276 			   vi->idev->propbit, INPUT_PROP_CNT);
277 	size = virtinput_cfg_select(vi, 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, VIRTIO_INPUT_CFG_EV_BITS, EV_KEY,
286 			   vi->idev->keybit, KEY_CNT);
287 	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_REL,
288 			   vi->idev->relbit, REL_CNT);
289 	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_ABS,
290 			   vi->idev->absbit, ABS_CNT);
291 	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_MSC,
292 			   vi->idev->mscbit, MSC_CNT);
293 	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SW,
294 			   vi->idev->swbit,  SW_CNT);
295 
296 	/* kernel -> device */
297 	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_LED,
298 			   vi->idev->ledbit, LED_CNT);
299 	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SND,
300 			   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(vi->idev, ABS_MT_SLOT) + 1;
311 			err = input_mt_init_slots(vi->idev, nslots, 0);
312 			if (err)
313 				goto err_mt_init_slots;
314 		}
315 	}
316 
317 	virtio_device_ready(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 
326 err_input_register:
327 	spin_lock_irqsave(&vi->lock, flags);
328 	vi->ready = false;
329 	spin_unlock_irqrestore(&vi->lock, flags);
330 err_mt_init_slots:
331 	input_free_device(vi->idev);
332 err_input_alloc:
333 	vdev->config->del_vqs(vdev);
334 err_init_vq:
335 	kfree(vi);
336 	return err;
337 }
338 
virtinput_remove(struct virtio_device * vdev)339 static 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(&vi->lock, flags);
348 
349 	input_unregister_device(vi->idev);
350 	virtio_reset_device(vdev);
351 	while ((buf = virtqueue_detach_unused_buf(vi->sts)) != NULL)
352 		kfree(buf);
353 	vdev->config->del_vqs(vdev);
354 	kfree(vi);
355 }
356 
357 #ifdef CONFIG_PM_SLEEP
virtinput_freeze(struct virtio_device * vdev)358 static 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(&vi->lock, flags);
366 
367 	vdev->config->del_vqs(vdev);
368 	return 0;
369 }
370 
virtinput_restore(struct virtio_device * vdev)371 static 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(vdev);
381 	vi->ready = true;
382 	virtinput_fill_evt(vi);
383 	return 0;
384 }
385 #endif
386 
387 static unsigned int features[] = {
388 	/* none */
389 };
390 static const struct virtio_device_id id_table[] = {
391 	{ VIRTIO_ID_INPUT, VIRTIO_DEV_ANY_ID },
392 	{ 0 },
393 };
394 
395 static 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 
409 module_virtio_driver(virtio_input_driver);
410 MODULE_DEVICE_TABLE(virtio, id_table);
411 
412 MODULE_LICENSE("GPL");
413 MODULE_DESCRIPTION("Virtio input device driver");
414 MODULE_AUTHOR("Gerd Hoffmann <kraxel@redhat.com>");
415