1 // SPDX-License-Identifier: GPL-2.0+
5  * Provides a user-space interface to properly handle clipboard/tablet
9  * use), or request detachment via user-space.
11  * Copyright (C) 2019-2022 Maximilian Luz <luzmaximilian@gmail.com>
34 /* -- SSAM interface. ------------------------------------------------------- */
136 /* -- Main structures. ------------------------------------------------------ */
191 	mutex_destroy(&ddev->write_lock);  in __sdtx_device_release()
198 		kref_get(&ddev->kref);  in sdtx_device_get()
206 		kref_put(&ddev->kref, __sdtx_device_release);  in sdtx_device_put()
210 /* -- Firmware value translations. ------------------------------------------ */
225 		dev_err(ddev->dev, "unknown base state: %#04x\n", state);  in sdtx_translate_base_state()
249 		dev_err(ddev->dev, "unknown latch status: %#04x\n", status);  in sdtx_translate_latch_status()
273 		dev_err(ddev->dev, "unknown cancel reason: %#04x\n", reason);  in sdtx_translate_cancel_reason()
279 /* -- IOCTLs. --------------------------------------------------------------- */
288 	lockdep_assert_held_read(&ddev->lock);  in sdtx_ioctl_get_base_info()
290 	status = ssam_retry(ssam_bas_get_base, ddev->ctrl, &raw);  in sdtx_ioctl_get_base_info()
298 		return -EFAULT;  in sdtx_ioctl_get_base_info()
308 	lockdep_assert_held_read(&ddev->lock);  in sdtx_ioctl_get_device_mode()
310 	status = ssam_retry(ssam_bas_get_device_mode, ddev->ctrl, &mode);  in sdtx_ioctl_get_device_mode()
319 	u8 latch;  in sdtx_ioctl_get_latch_status()  local
322 	lockdep_assert_held_read(&ddev->lock);  in sdtx_ioctl_get_latch_status()
324 	status = ssam_retry(ssam_bas_get_latch_status, ddev->ctrl, &latch);  in sdtx_ioctl_get_latch_status()
328 	return put_user(sdtx_translate_latch_status(ddev, latch), buf);  in sdtx_ioctl_get_latch_status()
333 	struct sdtx_device *ddev = client->ddev;  in __surface_dtx_ioctl()
335 	lockdep_assert_held_read(&ddev->lock);  in __surface_dtx_ioctl()
339 		set_bit(SDTX_CLIENT_EVENTS_ENABLED_BIT, &client->flags);  in __surface_dtx_ioctl()
343 		clear_bit(SDTX_CLIENT_EVENTS_ENABLED_BIT, &client->flags);  in __surface_dtx_ioctl()
347 		return ssam_retry(ssam_bas_latch_lock, ddev->ctrl);  in __surface_dtx_ioctl()
350 		return ssam_retry(ssam_bas_latch_unlock, ddev->ctrl);  in __surface_dtx_ioctl()
353 		return ssam_retry(ssam_bas_latch_request, ddev->ctrl);  in __surface_dtx_ioctl()
356 		return ssam_retry(ssam_bas_latch_confirm, ddev->ctrl);  in __surface_dtx_ioctl()
359 		return ssam_retry(ssam_bas_latch_heartbeat, ddev->ctrl);  in __surface_dtx_ioctl()
362 		return ssam_retry(ssam_bas_latch_cancel, ddev->ctrl);  in __surface_dtx_ioctl()
374 		return -EINVAL;  in __surface_dtx_ioctl()
380 	struct sdtx_client *client = file->private_data;  in surface_dtx_ioctl()
383 	if (down_read_killable(&client->ddev->lock))  in surface_dtx_ioctl()
384 		return -ERESTARTSYS;  in surface_dtx_ioctl()
386 	if (test_bit(SDTX_DEVICE_SHUTDOWN_BIT, &client->ddev->flags)) {  in surface_dtx_ioctl()
387 		up_read(&client->ddev->lock);  in surface_dtx_ioctl()
388 		return -ENODEV;  in surface_dtx_ioctl()
393 	up_read(&client->ddev->lock);  in surface_dtx_ioctl()
398 /* -- File operations. ------------------------------------------------------ */
402 	struct sdtx_device *ddev = container_of(file->private_data, struct sdtx_device, mdev);  in surface_dtx_open()
408 		return -ENOMEM;  in surface_dtx_open()
410 	client->ddev = sdtx_device_get(ddev);  in surface_dtx_open()
412 	INIT_LIST_HEAD(&client->node);  in surface_dtx_open()
414 	mutex_init(&client->read_lock);  in surface_dtx_open()
415 	INIT_KFIFO(client->buffer);  in surface_dtx_open()
417 	file->private_data = client;  in surface_dtx_open()
420 	down_write(&ddev->client_lock);  in surface_dtx_open()
428 	if (test_bit(SDTX_DEVICE_SHUTDOWN_BIT, &ddev->flags)) {  in surface_dtx_open()
429 		up_write(&ddev->client_lock);  in surface_dtx_open()
430 		mutex_destroy(&client->read_lock);  in surface_dtx_open()
431 		sdtx_device_put(client->ddev);  in surface_dtx_open()
433 		return -ENODEV;  in surface_dtx_open()
436 	list_add_tail(&client->node, &ddev->client_list);  in surface_dtx_open()
437 	up_write(&ddev->client_lock);  in surface_dtx_open()
445 	struct sdtx_client *client = file->private_data;  in surface_dtx_release()
448 	down_write(&client->ddev->client_lock);  in surface_dtx_release()
449 	list_del(&client->node);  in surface_dtx_release()
450 	up_write(&client->ddev->client_lock);  in surface_dtx_release()
453 	sdtx_device_put(client->ddev);  in surface_dtx_release()
454 	mutex_destroy(&client->read_lock);  in surface_dtx_release()
462 	struct sdtx_client *client = file->private_data;  in surface_dtx_read()
463 	struct sdtx_device *ddev = client->ddev;  in surface_dtx_read()
467 	if (down_read_killable(&ddev->lock))  in surface_dtx_read()
468 		return -ERESTARTSYS;  in surface_dtx_read()
471 	if (test_bit(SDTX_DEVICE_SHUTDOWN_BIT, &ddev->flags)) {  in surface_dtx_read()
472 		up_read(&ddev->lock);  in surface_dtx_read()
473 		return -ENODEV;  in surface_dtx_read()
478 		if (kfifo_is_empty(&client->buffer)) {  in surface_dtx_read()
479 			up_read(&ddev->lock);  in surface_dtx_read()
481 			if (file->f_flags & O_NONBLOCK)  in surface_dtx_read()
482 				return -EAGAIN;  in surface_dtx_read()
484 			status = wait_event_interruptible(ddev->waitq,  in surface_dtx_read()
485 							  !kfifo_is_empty(&client->buffer) ||  in surface_dtx_read()
487 								   &ddev->flags));  in surface_dtx_read()
491 			if (down_read_killable(&ddev->lock))  in surface_dtx_read()
492 				return -ERESTARTSYS;  in surface_dtx_read()
495 			if (test_bit(SDTX_DEVICE_SHUTDOWN_BIT, &ddev->flags)) {  in surface_dtx_read()
496 				up_read(&ddev->lock);  in surface_dtx_read()
497 				return -ENODEV;  in surface_dtx_read()
502 		if (mutex_lock_interruptible(&client->read_lock)) {  in surface_dtx_read()
503 			up_read(&ddev->lock);  in surface_dtx_read()
504 			return -ERESTARTSYS;  in surface_dtx_read()
507 		status = kfifo_to_user(&client->buffer, buf, count, &copied);  in surface_dtx_read()
508 		mutex_unlock(&client->read_lock);  in surface_dtx_read()
511 			up_read(&ddev->lock);  in surface_dtx_read()
516 		if (copied == 0 && (file->f_flags & O_NONBLOCK)) {  in surface_dtx_read()
517 			up_read(&ddev->lock);  in surface_dtx_read()
518 			return -EAGAIN;  in surface_dtx_read()
522 	up_read(&ddev->lock);  in surface_dtx_read()
528 	struct sdtx_client *client = file->private_data;  in surface_dtx_poll()
531 	if (test_bit(SDTX_DEVICE_SHUTDOWN_BIT, &client->ddev->flags))  in surface_dtx_poll()
534 	poll_wait(file, &client->ddev->waitq, pt);  in surface_dtx_poll()
536 	if (!kfifo_is_empty(&client->buffer))  in surface_dtx_poll()
544 	struct sdtx_client *client = file->private_data;  in surface_dtx_fasync()
546 	return fasync_helper(fd, file, on, &client->fasync);  in surface_dtx_fasync()
561 /* -- Event handling/forwarding. -------------------------------------------- */
567  * determine the new tablet-mode switch and device mode values after some
595 /* Must be executed with ddev->write_lock held. */
598 	const size_t len = sizeof(struct sdtx_event) + evt->length;  in sdtx_push_event()
601 	lockdep_assert_held(&ddev->write_lock);  in sdtx_push_event()
603 	down_read(&ddev->client_lock);  in sdtx_push_event()
604 	list_for_each_entry(client, &ddev->client_list, node) {  in sdtx_push_event()
605 		if (!test_bit(SDTX_CLIENT_EVENTS_ENABLED_BIT, &client->flags))  in sdtx_push_event()
608 		if (likely(kfifo_avail(&client->buffer) >= len))  in sdtx_push_event()
609 			kfifo_in(&client->buffer, (const u8 *)evt, len);  in sdtx_push_event()
611 			dev_warn(ddev->dev, "event buffer overrun\n");  in sdtx_push_event()
613 		kill_fasync(&client->fasync, SIGIO, POLL_IN);  in sdtx_push_event()
615 	up_read(&ddev->client_lock);  in sdtx_push_event()
617 	wake_up_interruptible(&ddev->waitq);  in sdtx_push_event()
627 	switch (in->command_id) {  in sdtx_notifier()
648 	if (in->length != len) {  in sdtx_notifier()
649 		dev_err(ddev->dev,  in sdtx_notifier()
651 			in->command_id, in->length, len);  in sdtx_notifier()
655 	mutex_lock(&ddev->write_lock);  in sdtx_notifier()
658 	switch (in->command_id) {  in sdtx_notifier()
660 		clear_bit(SDTX_DEVICE_DIRTY_BASE_BIT, &ddev->flags);  in sdtx_notifier()
663 		if (ddev->state.base.state == in->data[0] &&  in sdtx_notifier()
664 		    ddev->state.base.base_id == in->data[1])  in sdtx_notifier()
667 		ddev->state.base.state = in->data[0];  in sdtx_notifier()
668 		ddev->state.base.base_id = in->data[1];  in sdtx_notifier()
672 		event.base.v.state = sdtx_translate_base_state(ddev, in->data[0]);  in sdtx_notifier()
673 		event.base.v.base_id = SDTX_BASE_TYPE_SSH(in->data[1]);  in sdtx_notifier()
684 		event.status.v = sdtx_translate_cancel_reason(ddev, in->data[0]);  in sdtx_notifier()
688 		clear_bit(SDTX_DEVICE_DIRTY_LATCH_BIT, &ddev->flags);  in sdtx_notifier()
691 		if (ddev->state.latch_status == in->data[0])  in sdtx_notifier()
694 		ddev->state.latch_status = in->data[0];  in sdtx_notifier()
698 		event.status.v = sdtx_translate_latch_status(ddev, in->data[0]);  in sdtx_notifier()
705 	if (in->command_id == SAM_EVENT_CID_DTX_CONNECTION) {  in sdtx_notifier()
708 		delay = in->data[0] ? SDTX_DEVICE_MODE_DELAY_CONNECT : 0;  in sdtx_notifier()
713 	mutex_unlock(&ddev->write_lock);  in sdtx_notifier()
718 /* -- State update functions. ----------------------------------------------- */
737 	status = ssam_retry(ssam_bas_get_device_mode, ddev->ctrl, &mode);  in sdtx_device_mode_workfn()
739 		dev_err(ddev->dev, "failed to get device mode: %d\n", status);  in sdtx_device_mode_workfn()
744 	status = ssam_retry(ssam_bas_get_base, ddev->ctrl, &base);  in sdtx_device_mode_workfn()
746 		dev_err(ddev->dev, "failed to get base info: %d\n", status);  in sdtx_device_mode_workfn()
757 		dev_dbg(ddev->dev, "device mode is invalid, trying again\n");  in sdtx_device_mode_workfn()
762 	mutex_lock(&ddev->write_lock);  in sdtx_device_mode_workfn()
763 	clear_bit(SDTX_DEVICE_DIRTY_MODE_BIT, &ddev->flags);  in sdtx_device_mode_workfn()
765 	/* Avoid sending duplicate device-mode events. */  in sdtx_device_mode_workfn()
766 	if (ddev->state.device_mode == mode) {  in sdtx_device_mode_workfn()
767 		mutex_unlock(&ddev->write_lock);  in sdtx_device_mode_workfn()
771 	ddev->state.device_mode = mode;  in sdtx_device_mode_workfn()
781 	input_report_switch(ddev->mode_switch, SW_TABLET_MODE, tablet);  in sdtx_device_mode_workfn()
782 	input_sync(ddev->mode_switch);  in sdtx_device_mode_workfn()
784 	mutex_unlock(&ddev->write_lock);  in sdtx_device_mode_workfn()
789 	schedule_delayed_work(&ddev->mode_work, delay);  in sdtx_update_device_mode()
792 /* Must be executed with ddev->write_lock held. */
798 	lockdep_assert_held(&ddev->write_lock);  in __sdtx_device_state_update_base()
801 	if (ddev->state.base.state == info.state &&  in __sdtx_device_state_update_base()
802 	    ddev->state.base.base_id == info.base_id)  in __sdtx_device_state_update_base()
805 	ddev->state.base = info;  in __sdtx_device_state_update_base()
815 /* Must be executed with ddev->write_lock held. */
827 	lockdep_assert_held(&ddev->write_lock);  in __sdtx_device_state_update_mode()
829 	if (sdtx_device_mode_invalid(mode, ddev->state.base.state)) {  in __sdtx_device_state_update_mode()
830 		dev_dbg(ddev->dev, "device mode is invalid, trying again\n");  in __sdtx_device_state_update_mode()
836 	if (ddev->state.device_mode == mode)  in __sdtx_device_state_update_mode()
839 	ddev->state.device_mode = mode;  in __sdtx_device_state_update_mode()
850 	input_report_switch(ddev->mode_switch, SW_TABLET_MODE, tablet);  in __sdtx_device_state_update_mode()
851 	input_sync(ddev->mode_switch);  in __sdtx_device_state_update_mode()
854 /* Must be executed with ddev->write_lock held. */
859 	lockdep_assert_held(&ddev->write_lock);  in __sdtx_device_state_update_latch()
862 	if (ddev->state.latch_status == status)  in __sdtx_device_state_update_latch()
865 	ddev->state.latch_status = status;  in __sdtx_device_state_update_latch()
878 	u8 mode, latch;  in sdtx_device_state_workfn()  local
882 	set_bit(SDTX_DEVICE_DIRTY_BASE_BIT, &ddev->flags);  in sdtx_device_state_workfn()
883 	set_bit(SDTX_DEVICE_DIRTY_MODE_BIT, &ddev->flags);  in sdtx_device_state_workfn()
884 	set_bit(SDTX_DEVICE_DIRTY_LATCH_BIT, &ddev->flags);  in sdtx_device_state_workfn()
894 	status = ssam_retry(ssam_bas_get_base, ddev->ctrl, &base);  in sdtx_device_state_workfn()
896 		dev_err(ddev->dev, "failed to get base state: %d\n", status);  in sdtx_device_state_workfn()
900 	status = ssam_retry(ssam_bas_get_device_mode, ddev->ctrl, &mode);  in sdtx_device_state_workfn()
902 		dev_err(ddev->dev, "failed to get device mode: %d\n", status);  in sdtx_device_state_workfn()
906 	status = ssam_retry(ssam_bas_get_latch_status, ddev->ctrl, &latch);  in sdtx_device_state_workfn()
908 		dev_err(ddev->dev, "failed to get latch status: %d\n", status);  in sdtx_device_state_workfn()
912 	mutex_lock(&ddev->write_lock);  in sdtx_device_state_workfn()
915 	 * If the respective dirty-bit has been cleared, an event has been  in sdtx_device_state_workfn()
922 	if (test_and_clear_bit(SDTX_DEVICE_DIRTY_BASE_BIT, &ddev->flags))  in sdtx_device_state_workfn()
925 	if (test_and_clear_bit(SDTX_DEVICE_DIRTY_MODE_BIT, &ddev->flags))  in sdtx_device_state_workfn()
928 	if (test_and_clear_bit(SDTX_DEVICE_DIRTY_LATCH_BIT, &ddev->flags))  in sdtx_device_state_workfn()
929 		__sdtx_device_state_update_latch(ddev, latch);  in sdtx_device_state_workfn()
931 	mutex_unlock(&ddev->write_lock);  in sdtx_device_state_workfn()
936 	schedule_delayed_work(&ddev->state_work, delay);  in sdtx_update_device_state()
940 /* -- Common device initialization. ----------------------------------------- */
948 	kref_init(&ddev->kref);  in sdtx_device_init()
949 	init_rwsem(&ddev->lock);  in sdtx_device_init()
950 	ddev->dev = dev;  in sdtx_device_init()
951 	ddev->ctrl = ctrl;  in sdtx_device_init()
953 	ddev->mdev.minor = MISC_DYNAMIC_MINOR;  in sdtx_device_init()
954 	ddev->mdev.name = "surface_dtx";  in sdtx_device_init()
955 	ddev->mdev.nodename = "surface/dtx";  in sdtx_device_init()
956 	ddev->mdev.fops = &surface_dtx_fops;  in sdtx_device_init()
958 	ddev->notif.base.priority = 1;  in sdtx_device_init()
959 	ddev->notif.base.fn = sdtx_notifier;  in sdtx_device_init()
960 	ddev->notif.event.reg = SSAM_EVENT_REGISTRY_SAM;  in sdtx_device_init()
961 	ddev->notif.event.id.target_category = SSAM_SSH_TC_BAS;  in sdtx_device_init()
962 	ddev->notif.event.id.instance = 0;  in sdtx_device_init()
963 	ddev->notif.event.mask = SSAM_EVENT_MASK_NONE;  in sdtx_device_init()
964 	ddev->notif.event.flags = SSAM_EVENT_SEQUENCED;  in sdtx_device_init()
966 	init_waitqueue_head(&ddev->waitq);  in sdtx_device_init()
967 	mutex_init(&ddev->write_lock);  in sdtx_device_init()
968 	init_rwsem(&ddev->client_lock);  in sdtx_device_init()
969 	INIT_LIST_HEAD(&ddev->client_list);  in sdtx_device_init()
971 	INIT_DELAYED_WORK(&ddev->mode_work, sdtx_device_mode_workfn);  in sdtx_device_init()
972 	INIT_DELAYED_WORK(&ddev->state_work, sdtx_device_state_workfn);  in sdtx_device_init()
985 	status = ssam_retry(ssam_bas_get_base, ddev->ctrl, &ddev->state.base);  in sdtx_device_init()
989 	status = ssam_retry(ssam_bas_get_device_mode, ddev->ctrl, &ddev->state.device_mode);  in sdtx_device_init()
993 	status = ssam_retry(ssam_bas_get_latch_status, ddev->ctrl, &ddev->state.latch_status);  in sdtx_device_init()
998 	ddev->mode_switch = input_allocate_device();  in sdtx_device_init()
999 	if (!ddev->mode_switch)  in sdtx_device_init()
1000 		return -ENOMEM;  in sdtx_device_init()
1002 	ddev->mode_switch->name = "Microsoft Surface DTX Device Mode Switch";  in sdtx_device_init()
1003 	ddev->mode_switch->phys = "ssam/01:11:01:00:00/input0";  in sdtx_device_init()
1004 	ddev->mode_switch->id.bustype = BUS_HOST;  in sdtx_device_init()
1005 	ddev->mode_switch->dev.parent = ddev->dev;  in sdtx_device_init()
1007 	tablet_mode = (ddev->state.device_mode != SDTX_DEVICE_MODE_LAPTOP);  in sdtx_device_init()
1008 	input_set_capability(ddev->mode_switch, EV_SW, SW_TABLET_MODE);  in sdtx_device_init()
1009 	input_report_switch(ddev->mode_switch, SW_TABLET_MODE, tablet_mode);  in sdtx_device_init()
1011 	status = input_register_device(ddev->mode_switch);  in sdtx_device_init()
1013 		input_free_device(ddev->mode_switch);  in sdtx_device_init()
1018 	status = ssam_notifier_register(ddev->ctrl, &ddev->notif);  in sdtx_device_init()
1023 	status = misc_register(&ddev->mdev);  in sdtx_device_init()
1035 	ssam_notifier_unregister(ddev->ctrl, &ddev->notif);  in sdtx_device_init()
1036 	cancel_delayed_work_sync(&ddev->mode_work);  in sdtx_device_init()
1038 	input_unregister_device(ddev->mode_switch);  in sdtx_device_init()
1049 		return ERR_PTR(-ENOMEM);  in sdtx_device_create()
1065 	 * Mark device as shut-down. Prevent new clients from being added and  in sdtx_device_destroy()
1068 	set_bit(SDTX_DEVICE_SHUTDOWN_BIT, &ddev->flags);  in sdtx_device_destroy()
1071 	ssam_notifier_unregister(ddev->ctrl, &ddev->notif);  in sdtx_device_destroy()
1074 	cancel_delayed_work_sync(&ddev->mode_work);  in sdtx_device_destroy()
1077 	cancel_delayed_work_sync(&ddev->state_work);  in sdtx_device_destroy()
1080 	input_unregister_device(ddev->mode_switch);  in sdtx_device_destroy()
1083 	down_write(&ddev->client_lock);  in sdtx_device_destroy()
1084 	list_for_each_entry(client, &ddev->client_list, node) {  in sdtx_device_destroy()
1085 		kill_fasync(&client->fasync, SIGIO, POLL_HUP);  in sdtx_device_destroy()
1087 	up_write(&ddev->client_lock);  in sdtx_device_destroy()
1090 	wake_up_interruptible(&ddev->waitq);  in sdtx_device_destroy()
1097 	down_write(&ddev->lock);  in sdtx_device_destroy()
1098 	ddev->dev = NULL;  in sdtx_device_destroy()
1099 	ddev->ctrl = NULL;  in sdtx_device_destroy()
1100 	up_write(&ddev->lock);  in sdtx_device_destroy()
1102 	/* Finally remove the misc-device. */  in sdtx_device_destroy()
1103 	misc_deregister(&ddev->mdev);  in sdtx_device_destroy()
1113 /* -- PM ops. --------------------------------------------------------------- */
1123 	 * display-off state) and release them when resumed (i.e. transitioned  in surface_dtx_pm_complete()
1124 	 * to display-on state). During hibernation, however, the EC will be  in surface_dtx_pm_complete()
1150 /* -- Platform driver. ------------------------------------------------------ */
1158 	ctrl = ssam_client_bind(&pdev->dev);  in surface_dtx_platform_probe()
1160 		return PTR_ERR(ctrl) == -ENODEV ? -EPROBE_DEFER : PTR_ERR(ctrl);  in surface_dtx_platform_probe()
1162 	ddev = sdtx_device_create(&pdev->dev, ctrl);  in surface_dtx_platform_probe()
1193 /* -- SSAM device driver. --------------------------------------------------- */
1201 	ddev = sdtx_device_create(&sdev->dev, sdev->ctrl);  in surface_dtx_ssam_probe()
1255 /* -- Module setup. --------------------------------------------------------- */
1281 MODULE_DESCRIPTION("Detachment-system driver for Surface System Aggregator Module");