1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2023 Intel Corporation. All rights reserved.
4 * Intel Visual Sensing Controller ACE Linux driver
5 */
6
7/*
8 * To set ownership of camera sensor, there is specific command, which
9 * is sent via MEI protocol. That's a two-step scheme where the firmware
10 * first acks receipt of the command and later responses the command was
11 * executed. The command sending function uses "completion" as the
12 * synchronization mechanism. The notification for command is received
13 * via a mei callback which wakes up the caller. There can be only one
14 * outstanding command at a time.
15 *
16 * The power line of camera sensor is directly connected to IVSC instead
17 * of host, when camera sensor ownership is switched to host, sensor is
18 * already powered up by firmware.
19 */
20
21#include <linux/acpi.h>
22#include <linux/completion.h>
23#include <linux/delay.h>
24#include <linux/kernel.h>
25#include <linux/mei_cl_bus.h>
26#include <linux/module.h>
27#include <linux/mutex.h>
28#include <linux/pm_runtime.h>
29#include <linux/slab.h>
30#include <linux/uuid.h>
31#include <linux/workqueue.h>
32
33/* indicating driver message */
34#define	ACE_DRV_MSG		1
35/* indicating set command */
36#define	ACE_CMD_SET		4
37/* command timeout determined experimentally */
38#define	ACE_CMD_TIMEOUT		(5 * HZ)
39/* indicating the first command block */
40#define	ACE_CMD_INIT_BLOCK	1
41/* indicating the last command block */
42#define	ACE_CMD_FINAL_BLOCK	1
43/* size of camera status notification content */
44#define	ACE_CAMERA_STATUS_SIZE	5
45
46/* UUID used to get firmware id */
47#define ACE_GET_FW_ID_UUID UUID_LE(0x6167DCFB, 0x72F1, 0x4584, 0xBF, \
48				   0xE3, 0x84, 0x17, 0x71, 0xAA, 0x79, 0x0B)
49
50/* UUID used to get csi device */
51#define MEI_CSI_UUID UUID_LE(0x92335FCF, 0x3203, 0x4472, \
52			     0xAF, 0x93, 0x7b, 0x44, 0x53, 0xAC, 0x29, 0xDA)
53
54/* identify firmware event type */
55enum ace_event_type {
56	/* firmware ready */
57	ACE_FW_READY = 0x8,
58
59	/* command response */
60	ACE_CMD_RESPONSE = 0x10,
61};
62
63/* identify camera sensor ownership */
64enum ace_camera_owner {
65	ACE_CAMERA_IVSC,
66	ACE_CAMERA_HOST,
67};
68
69/* identify the command id supported by firmware IPC */
70enum ace_cmd_id {
71	/* used to switch camera sensor to host */
72	ACE_SWITCH_CAMERA_TO_HOST = 0x13,
73
74	/* used to switch camera sensor to IVSC */
75	ACE_SWITCH_CAMERA_TO_IVSC = 0x14,
76
77	/* used to get firmware id */
78	ACE_GET_FW_ID = 0x1A,
79};
80
81/* ACE command header structure */
82struct ace_cmd_hdr {
83	u32 firmware_id : 16;
84	u32 instance_id : 8;
85	u32 type : 5;
86	u32 rsp : 1;
87	u32 msg_tgt : 1;
88	u32 _hw_rsvd_1 : 1;
89	u32 param_size : 20;
90	u32 cmd_id : 8;
91	u32 final_block : 1;
92	u32 init_block : 1;
93	u32 _hw_rsvd_2 : 2;
94} __packed;
95
96/* ACE command parameter structure */
97union ace_cmd_param {
98	uuid_le uuid;
99	u32 param;
100};
101
102/* ACE command structure */
103struct ace_cmd {
104	struct ace_cmd_hdr hdr;
105	union ace_cmd_param param;
106} __packed;
107
108/* ACE notification header */
109union ace_notif_hdr {
110	struct _confirm {
111		u32 status : 24;
112		u32 type : 5;
113		u32 rsp : 1;
114		u32 msg_tgt : 1;
115		u32 _hw_rsvd_1 : 1;
116		u32 param_size : 20;
117		u32 cmd_id : 8;
118		u32 final_block : 1;
119		u32 init_block : 1;
120		u32 _hw_rsvd_2 : 2;
121	} __packed ack;
122
123	struct _event {
124		u32 rsvd1 : 16;
125		u32 event_type : 8;
126		u32 type : 5;
127		u32 ack : 1;
128		u32 msg_tgt : 1;
129		u32 _hw_rsvd_1 : 1;
130		u32 rsvd2 : 30;
131		u32 _hw_rsvd_2 : 2;
132	} __packed event;
133
134	struct _response {
135		u32 event_id : 16;
136		u32 notif_type : 8;
137		u32 type : 5;
138		u32 rsp : 1;
139		u32 msg_tgt : 1;
140		u32 _hw_rsvd_1 : 1;
141		u32 event_data_size : 16;
142		u32 request_target : 1;
143		u32 request_type : 5;
144		u32 cmd_id : 8;
145		u32 _hw_rsvd_2 : 2;
146	} __packed response;
147};
148
149/* ACE notification content */
150union ace_notif_cont {
151	u16 firmware_id;
152	u8 state_notif;
153	u8 camera_status[ACE_CAMERA_STATUS_SIZE];
154};
155
156/* ACE notification structure */
157struct ace_notif {
158	union ace_notif_hdr hdr;
159	union ace_notif_cont cont;
160} __packed;
161
162struct mei_ace {
163	struct mei_cl_device *cldev;
164
165	/* command ack */
166	struct ace_notif cmd_ack;
167	/* command response */
168	struct ace_notif cmd_response;
169	/* used to wait for command ack and response */
170	struct completion cmd_completion;
171	/* lock used to prevent multiple call to send command */
172	struct mutex lock;
173
174	/* used to construct command */
175	u16 firmware_id;
176
177	struct device *csi_dev;
178
179	/* runtime PM link from ace to csi */
180	struct device_link *csi_link;
181
182	struct work_struct work;
183};
184
185static inline void init_cmd_hdr(struct ace_cmd_hdr *hdr)
186{
187	memset(hdr, 0, sizeof(struct ace_cmd_hdr));
188
189	hdr->type = ACE_CMD_SET;
190	hdr->msg_tgt = ACE_DRV_MSG;
191	hdr->init_block = ACE_CMD_INIT_BLOCK;
192	hdr->final_block = ACE_CMD_FINAL_BLOCK;
193}
194
195static int construct_command(struct mei_ace *ace, struct ace_cmd *cmd,
196			     enum ace_cmd_id cmd_id)
197{
198	union ace_cmd_param *param = &cmd->param;
199	struct ace_cmd_hdr *hdr = &cmd->hdr;
200
201	init_cmd_hdr(hdr);
202
203	hdr->cmd_id = cmd_id;
204	switch (cmd_id) {
205	case ACE_GET_FW_ID:
206		param->uuid = ACE_GET_FW_ID_UUID;
207		hdr->param_size = sizeof(param->uuid);
208		break;
209	case ACE_SWITCH_CAMERA_TO_IVSC:
210		param->param = 0;
211		hdr->firmware_id = ace->firmware_id;
212		hdr->param_size = sizeof(param->param);
213		break;
214	case ACE_SWITCH_CAMERA_TO_HOST:
215		hdr->firmware_id = ace->firmware_id;
216		break;
217	default:
218		return -EINVAL;
219	}
220
221	return hdr->param_size + sizeof(cmd->hdr);
222}
223
224/* send command to firmware */
225static int mei_ace_send(struct mei_ace *ace, struct ace_cmd *cmd,
226			size_t len, bool only_ack)
227{
228	union ace_notif_hdr *resp_hdr = &ace->cmd_response.hdr;
229	union ace_notif_hdr *ack_hdr = &ace->cmd_ack.hdr;
230	struct ace_cmd_hdr *cmd_hdr = &cmd->hdr;
231	int ret;
232
233	mutex_lock(&ace->lock);
234
235	reinit_completion(&ace->cmd_completion);
236
237	ret = mei_cldev_send(ace->cldev, (u8 *)cmd, len);
238	if (ret < 0)
239		goto out;
240
241	ret = wait_for_completion_killable_timeout(&ace->cmd_completion,
242						   ACE_CMD_TIMEOUT);
243	if (ret < 0) {
244		goto out;
245	} else if (!ret) {
246		ret = -ETIMEDOUT;
247		goto out;
248	}
249
250	if (ack_hdr->ack.cmd_id != cmd_hdr->cmd_id) {
251		ret = -EINVAL;
252		goto out;
253	}
254
255	/* command ack status */
256	ret = ack_hdr->ack.status;
257	if (ret) {
258		ret = -EIO;
259		goto out;
260	}
261
262	if (only_ack)
263		goto out;
264
265	ret = wait_for_completion_killable_timeout(&ace->cmd_completion,
266						   ACE_CMD_TIMEOUT);
267	if (ret < 0) {
268		goto out;
269	} else if (!ret) {
270		ret = -ETIMEDOUT;
271		goto out;
272	} else {
273		ret = 0;
274	}
275
276	if (resp_hdr->response.cmd_id != cmd_hdr->cmd_id)
277		ret = -EINVAL;
278
279out:
280	mutex_unlock(&ace->lock);
281
282	return ret;
283}
284
285static int ace_set_camera_owner(struct mei_ace *ace,
286				enum ace_camera_owner owner)
287{
288	enum ace_cmd_id cmd_id;
289	struct ace_cmd cmd;
290	int cmd_size;
291	int ret;
292
293	if (owner == ACE_CAMERA_IVSC)
294		cmd_id = ACE_SWITCH_CAMERA_TO_IVSC;
295	else
296		cmd_id = ACE_SWITCH_CAMERA_TO_HOST;
297
298	cmd_size = construct_command(ace, &cmd, cmd_id);
299	if (cmd_size >= 0)
300		ret = mei_ace_send(ace, &cmd, cmd_size, false);
301	else
302		ret = cmd_size;
303
304	return ret;
305}
306
307/* the first command downloaded to firmware */
308static inline int ace_get_firmware_id(struct mei_ace *ace)
309{
310	struct ace_cmd cmd;
311	int cmd_size;
312	int ret;
313
314	cmd_size = construct_command(ace, &cmd, ACE_GET_FW_ID);
315	if (cmd_size >= 0)
316		ret = mei_ace_send(ace, &cmd, cmd_size, true);
317	else
318		ret = cmd_size;
319
320	return ret;
321}
322
323static void handle_command_response(struct mei_ace *ace,
324				    struct ace_notif *resp, int len)
325{
326	union ace_notif_hdr *hdr = &resp->hdr;
327
328	switch (hdr->response.cmd_id) {
329	case ACE_SWITCH_CAMERA_TO_IVSC:
330	case ACE_SWITCH_CAMERA_TO_HOST:
331		memcpy(&ace->cmd_response, resp, len);
332		complete(&ace->cmd_completion);
333		break;
334	case ACE_GET_FW_ID:
335		break;
336	default:
337		break;
338	}
339}
340
341static void handle_command_ack(struct mei_ace *ace,
342			       struct ace_notif *ack, int len)
343{
344	union ace_notif_hdr *hdr = &ack->hdr;
345
346	switch (hdr->ack.cmd_id) {
347	case ACE_GET_FW_ID:
348		ace->firmware_id = ack->cont.firmware_id;
349		fallthrough;
350	case ACE_SWITCH_CAMERA_TO_IVSC:
351	case ACE_SWITCH_CAMERA_TO_HOST:
352		memcpy(&ace->cmd_ack, ack, len);
353		complete(&ace->cmd_completion);
354		break;
355	default:
356		break;
357	}
358}
359
360/* callback for receive */
361static void mei_ace_rx(struct mei_cl_device *cldev)
362{
363	struct mei_ace *ace = mei_cldev_get_drvdata(cldev);
364	struct ace_notif event;
365	union ace_notif_hdr *hdr = &event.hdr;
366	int ret;
367
368	ret = mei_cldev_recv(cldev, (u8 *)&event, sizeof(event));
369	if (ret < 0) {
370		dev_err(&cldev->dev, "recv error: %d\n", ret);
371		return;
372	}
373
374	if (hdr->event.ack) {
375		handle_command_ack(ace, &event, ret);
376		return;
377	}
378
379	switch (hdr->event.event_type) {
380	case ACE_CMD_RESPONSE:
381		handle_command_response(ace, &event, ret);
382		break;
383	case ACE_FW_READY:
384		/*
385		 * firmware ready notification sent to driver
386		 * after HECI client connected with firmware.
387		 */
388		dev_dbg(&cldev->dev, "firmware ready\n");
389		break;
390	default:
391		break;
392	}
393}
394
395static int mei_ace_setup_dev_link(struct mei_ace *ace)
396{
397	struct device *dev = &ace->cldev->dev;
398	uuid_le uuid = MEI_CSI_UUID;
399	struct device *csi_dev;
400	char name[64];
401	int ret;
402
403	snprintf(name, sizeof(name), "%s-%pUl", dev_name(dev->parent), &uuid);
404
405	csi_dev = device_find_child_by_name(dev->parent, name);
406	if (!csi_dev) {
407		ret = -EPROBE_DEFER;
408		goto err;
409	} else if (!dev_fwnode(csi_dev)) {
410		ret = -EPROBE_DEFER;
411		goto err_put;
412	}
413
414	/* setup link between mei_ace and mei_csi */
415	ace->csi_link = device_link_add(csi_dev, dev, DL_FLAG_PM_RUNTIME |
416					DL_FLAG_RPM_ACTIVE | DL_FLAG_STATELESS);
417	if (!ace->csi_link) {
418		ret = -EINVAL;
419		dev_err(dev, "failed to link to %s\n", dev_name(csi_dev));
420		goto err_put;
421	}
422
423	ace->csi_dev = csi_dev;
424
425	return 0;
426
427err_put:
428	put_device(csi_dev);
429
430err:
431	return ret;
432}
433
434/* switch camera to host before probe sensor device */
435static void mei_ace_post_probe_work(struct work_struct *work)
436{
437	struct acpi_device *adev;
438	struct mei_ace *ace;
439	struct device *dev;
440	int ret;
441
442	ace = container_of(work, struct mei_ace, work);
443	dev = &ace->cldev->dev;
444
445	ret = ace_set_camera_owner(ace, ACE_CAMERA_HOST);
446	if (ret) {
447		dev_err(dev, "switch camera to host failed: %d\n", ret);
448		return;
449	}
450
451	adev = ACPI_COMPANION(dev->parent);
452	if (!adev)
453		return;
454
455	acpi_dev_clear_dependencies(adev);
456}
457
458static int mei_ace_probe(struct mei_cl_device *cldev,
459			 const struct mei_cl_device_id *id)
460{
461	struct device *dev = &cldev->dev;
462	struct mei_ace *ace;
463	int ret;
464
465	ace = devm_kzalloc(dev, sizeof(struct mei_ace), GFP_KERNEL);
466	if (!ace)
467		return -ENOMEM;
468
469	ace->cldev = cldev;
470	mutex_init(&ace->lock);
471	init_completion(&ace->cmd_completion);
472	INIT_WORK(&ace->work, mei_ace_post_probe_work);
473
474	mei_cldev_set_drvdata(cldev, ace);
475
476	ret = mei_cldev_enable(cldev);
477	if (ret < 0) {
478		dev_err(dev, "mei_cldev_enable failed: %d\n", ret);
479		goto destroy_mutex;
480	}
481
482	ret = mei_cldev_register_rx_cb(cldev, mei_ace_rx);
483	if (ret) {
484		dev_err(dev, "event cb registration failed: %d\n", ret);
485		goto err_disable;
486	}
487
488	ret = ace_get_firmware_id(ace);
489	if (ret) {
490		dev_err(dev, "get firmware id failed: %d\n", ret);
491		goto err_disable;
492	}
493
494	pm_runtime_set_active(dev);
495	pm_runtime_enable(dev);
496
497	ret = mei_ace_setup_dev_link(ace);
498	if (ret)
499		goto disable_pm;
500
501	schedule_work(&ace->work);
502
503	return 0;
504
505disable_pm:
506	pm_runtime_disable(dev);
507	pm_runtime_set_suspended(dev);
508
509err_disable:
510	mei_cldev_disable(cldev);
511
512destroy_mutex:
513	mutex_destroy(&ace->lock);
514
515	return ret;
516}
517
518static void mei_ace_remove(struct mei_cl_device *cldev)
519{
520	struct mei_ace *ace = mei_cldev_get_drvdata(cldev);
521
522	cancel_work_sync(&ace->work);
523
524	device_link_del(ace->csi_link);
525	put_device(ace->csi_dev);
526
527	pm_runtime_disable(&cldev->dev);
528	pm_runtime_set_suspended(&cldev->dev);
529
530	ace_set_camera_owner(ace, ACE_CAMERA_IVSC);
531
532	mutex_destroy(&ace->lock);
533}
534
535static int __maybe_unused mei_ace_runtime_suspend(struct device *dev)
536{
537	struct mei_ace *ace = dev_get_drvdata(dev);
538
539	return ace_set_camera_owner(ace, ACE_CAMERA_IVSC);
540}
541
542static int __maybe_unused mei_ace_runtime_resume(struct device *dev)
543{
544	struct mei_ace *ace = dev_get_drvdata(dev);
545
546	return ace_set_camera_owner(ace, ACE_CAMERA_HOST);
547}
548
549static const struct dev_pm_ops mei_ace_pm_ops = {
550	SET_RUNTIME_PM_OPS(mei_ace_runtime_suspend,
551			   mei_ace_runtime_resume, NULL)
552};
553
554#define MEI_ACE_UUID UUID_LE(0x5DB76CF6, 0x0A68, 0x4ED6, \
555			     0x9B, 0x78, 0x03, 0x61, 0x63, 0x5E, 0x24, 0x47)
556
557static const struct mei_cl_device_id mei_ace_tbl[] = {
558	{ .uuid = MEI_ACE_UUID, .version = MEI_CL_VERSION_ANY },
559	{ /* sentinel */ }
560};
561MODULE_DEVICE_TABLE(mei, mei_ace_tbl);
562
563static struct mei_cl_driver mei_ace_driver = {
564	.id_table = mei_ace_tbl,
565	.name = KBUILD_MODNAME,
566
567	.probe = mei_ace_probe,
568	.remove = mei_ace_remove,
569
570	.driver = {
571		.pm = &mei_ace_pm_ops,
572	},
573};
574
575module_mei_cl_driver(mei_ace_driver);
576
577MODULE_AUTHOR("Wentong Wu <wentong.wu@intel.com>");
578MODULE_AUTHOR("Zhifeng Wang <zhifeng.wang@intel.com>");
579MODULE_DESCRIPTION("Device driver for IVSC ACE");
580MODULE_LICENSE("GPL");
581