1283 lines · c
1// SPDX-License-Identifier: GPL-2.0+2/*3 * Surface Book (gen. 2 and later) detachment system (DTX) driver.4 *5 * Provides a user-space interface to properly handle clipboard/tablet6 * (containing screen and processor) detachment from the base of the device7 * (containing the keyboard and optionally a discrete GPU). Allows to8 * acknowledge (to speed things up), abort (e.g. in case the dGPU is still in9 * use), or request detachment via user-space.10 *11 * Copyright (C) 2019-2022 Maximilian Luz <luzmaximilian@gmail.com>12 */13 14#include <linux/fs.h>15#include <linux/input.h>16#include <linux/ioctl.h>17#include <linux/kernel.h>18#include <linux/kfifo.h>19#include <linux/kref.h>20#include <linux/miscdevice.h>21#include <linux/module.h>22#include <linux/mutex.h>23#include <linux/platform_device.h>24#include <linux/poll.h>25#include <linux/rwsem.h>26#include <linux/slab.h>27#include <linux/workqueue.h>28 29#include <linux/surface_aggregator/controller.h>30#include <linux/surface_aggregator/device.h>31#include <linux/surface_aggregator/dtx.h>32 33 34/* -- SSAM interface. ------------------------------------------------------- */35 36enum sam_event_cid_bas {37 SAM_EVENT_CID_DTX_CONNECTION = 0x0c,38 SAM_EVENT_CID_DTX_REQUEST = 0x0e,39 SAM_EVENT_CID_DTX_CANCEL = 0x0f,40 SAM_EVENT_CID_DTX_LATCH_STATUS = 0x11,41};42 43enum ssam_bas_base_state {44 SSAM_BAS_BASE_STATE_DETACH_SUCCESS = 0x00,45 SSAM_BAS_BASE_STATE_ATTACHED = 0x01,46 SSAM_BAS_BASE_STATE_NOT_FEASIBLE = 0x02,47};48 49enum ssam_bas_latch_status {50 SSAM_BAS_LATCH_STATUS_CLOSED = 0x00,51 SSAM_BAS_LATCH_STATUS_OPENED = 0x01,52 SSAM_BAS_LATCH_STATUS_FAILED_TO_OPEN = 0x02,53 SSAM_BAS_LATCH_STATUS_FAILED_TO_REMAIN_OPEN = 0x03,54 SSAM_BAS_LATCH_STATUS_FAILED_TO_CLOSE = 0x04,55};56 57enum ssam_bas_cancel_reason {58 SSAM_BAS_CANCEL_REASON_NOT_FEASIBLE = 0x00, /* Low battery. */59 SSAM_BAS_CANCEL_REASON_TIMEOUT = 0x02,60 SSAM_BAS_CANCEL_REASON_FAILED_TO_OPEN = 0x03,61 SSAM_BAS_CANCEL_REASON_FAILED_TO_REMAIN_OPEN = 0x04,62 SSAM_BAS_CANCEL_REASON_FAILED_TO_CLOSE = 0x05,63};64 65struct ssam_bas_base_info {66 u8 state;67 u8 base_id;68} __packed;69 70static_assert(sizeof(struct ssam_bas_base_info) == 2);71 72SSAM_DEFINE_SYNC_REQUEST_N(ssam_bas_latch_lock, {73 .target_category = SSAM_SSH_TC_BAS,74 .target_id = SSAM_SSH_TID_SAM,75 .command_id = 0x06,76 .instance_id = 0x00,77});78 79SSAM_DEFINE_SYNC_REQUEST_N(ssam_bas_latch_unlock, {80 .target_category = SSAM_SSH_TC_BAS,81 .target_id = SSAM_SSH_TID_SAM,82 .command_id = 0x07,83 .instance_id = 0x00,84});85 86SSAM_DEFINE_SYNC_REQUEST_N(ssam_bas_latch_request, {87 .target_category = SSAM_SSH_TC_BAS,88 .target_id = SSAM_SSH_TID_SAM,89 .command_id = 0x08,90 .instance_id = 0x00,91});92 93SSAM_DEFINE_SYNC_REQUEST_N(ssam_bas_latch_confirm, {94 .target_category = SSAM_SSH_TC_BAS,95 .target_id = SSAM_SSH_TID_SAM,96 .command_id = 0x09,97 .instance_id = 0x00,98});99 100SSAM_DEFINE_SYNC_REQUEST_N(ssam_bas_latch_heartbeat, {101 .target_category = SSAM_SSH_TC_BAS,102 .target_id = SSAM_SSH_TID_SAM,103 .command_id = 0x0a,104 .instance_id = 0x00,105});106 107SSAM_DEFINE_SYNC_REQUEST_N(ssam_bas_latch_cancel, {108 .target_category = SSAM_SSH_TC_BAS,109 .target_id = SSAM_SSH_TID_SAM,110 .command_id = 0x0b,111 .instance_id = 0x00,112});113 114SSAM_DEFINE_SYNC_REQUEST_R(ssam_bas_get_base, struct ssam_bas_base_info, {115 .target_category = SSAM_SSH_TC_BAS,116 .target_id = SSAM_SSH_TID_SAM,117 .command_id = 0x0c,118 .instance_id = 0x00,119});120 121SSAM_DEFINE_SYNC_REQUEST_R(ssam_bas_get_device_mode, u8, {122 .target_category = SSAM_SSH_TC_BAS,123 .target_id = SSAM_SSH_TID_SAM,124 .command_id = 0x0d,125 .instance_id = 0x00,126});127 128SSAM_DEFINE_SYNC_REQUEST_R(ssam_bas_get_latch_status, u8, {129 .target_category = SSAM_SSH_TC_BAS,130 .target_id = SSAM_SSH_TID_SAM,131 .command_id = 0x11,132 .instance_id = 0x00,133});134 135 136/* -- Main structures. ------------------------------------------------------ */137 138enum sdtx_device_state {139 SDTX_DEVICE_SHUTDOWN_BIT = BIT(0),140 SDTX_DEVICE_DIRTY_BASE_BIT = BIT(1),141 SDTX_DEVICE_DIRTY_MODE_BIT = BIT(2),142 SDTX_DEVICE_DIRTY_LATCH_BIT = BIT(3),143};144 145struct sdtx_device {146 struct kref kref;147 struct rw_semaphore lock; /* Guards device and controller reference. */148 149 struct device *dev;150 struct ssam_controller *ctrl;151 unsigned long flags;152 153 struct miscdevice mdev;154 wait_queue_head_t waitq;155 struct mutex write_lock; /* Guards order of events/notifications. */156 struct rw_semaphore client_lock; /* Guards client list. */157 struct list_head client_list;158 159 struct delayed_work state_work;160 struct {161 struct ssam_bas_base_info base;162 u8 device_mode;163 u8 latch_status;164 } state;165 166 struct delayed_work mode_work;167 struct input_dev *mode_switch;168 169 struct ssam_event_notifier notif;170};171 172enum sdtx_client_state {173 SDTX_CLIENT_EVENTS_ENABLED_BIT = BIT(0),174};175 176struct sdtx_client {177 struct sdtx_device *ddev;178 struct list_head node;179 unsigned long flags;180 181 struct fasync_struct *fasync;182 183 struct mutex read_lock; /* Guards FIFO buffer read access. */184 DECLARE_KFIFO(buffer, u8, 512);185};186 187static void __sdtx_device_release(struct kref *kref)188{189 struct sdtx_device *ddev = container_of(kref, struct sdtx_device, kref);190 191 mutex_destroy(&ddev->write_lock);192 kfree(ddev);193}194 195static struct sdtx_device *sdtx_device_get(struct sdtx_device *ddev)196{197 if (ddev)198 kref_get(&ddev->kref);199 200 return ddev;201}202 203static void sdtx_device_put(struct sdtx_device *ddev)204{205 if (ddev)206 kref_put(&ddev->kref, __sdtx_device_release);207}208 209 210/* -- Firmware value translations. ------------------------------------------ */211 212static u16 sdtx_translate_base_state(struct sdtx_device *ddev, u8 state)213{214 switch (state) {215 case SSAM_BAS_BASE_STATE_ATTACHED:216 return SDTX_BASE_ATTACHED;217 218 case SSAM_BAS_BASE_STATE_DETACH_SUCCESS:219 return SDTX_BASE_DETACHED;220 221 case SSAM_BAS_BASE_STATE_NOT_FEASIBLE:222 return SDTX_DETACH_NOT_FEASIBLE;223 224 default:225 dev_err(ddev->dev, "unknown base state: %#04x\n", state);226 return SDTX_UNKNOWN(state);227 }228}229 230static u16 sdtx_translate_latch_status(struct sdtx_device *ddev, u8 status)231{232 switch (status) {233 case SSAM_BAS_LATCH_STATUS_CLOSED:234 return SDTX_LATCH_CLOSED;235 236 case SSAM_BAS_LATCH_STATUS_OPENED:237 return SDTX_LATCH_OPENED;238 239 case SSAM_BAS_LATCH_STATUS_FAILED_TO_OPEN:240 return SDTX_ERR_FAILED_TO_OPEN;241 242 case SSAM_BAS_LATCH_STATUS_FAILED_TO_REMAIN_OPEN:243 return SDTX_ERR_FAILED_TO_REMAIN_OPEN;244 245 case SSAM_BAS_LATCH_STATUS_FAILED_TO_CLOSE:246 return SDTX_ERR_FAILED_TO_CLOSE;247 248 default:249 dev_err(ddev->dev, "unknown latch status: %#04x\n", status);250 return SDTX_UNKNOWN(status);251 }252}253 254static u16 sdtx_translate_cancel_reason(struct sdtx_device *ddev, u8 reason)255{256 switch (reason) {257 case SSAM_BAS_CANCEL_REASON_NOT_FEASIBLE:258 return SDTX_DETACH_NOT_FEASIBLE;259 260 case SSAM_BAS_CANCEL_REASON_TIMEOUT:261 return SDTX_DETACH_TIMEDOUT;262 263 case SSAM_BAS_CANCEL_REASON_FAILED_TO_OPEN:264 return SDTX_ERR_FAILED_TO_OPEN;265 266 case SSAM_BAS_CANCEL_REASON_FAILED_TO_REMAIN_OPEN:267 return SDTX_ERR_FAILED_TO_REMAIN_OPEN;268 269 case SSAM_BAS_CANCEL_REASON_FAILED_TO_CLOSE:270 return SDTX_ERR_FAILED_TO_CLOSE;271 272 default:273 dev_err(ddev->dev, "unknown cancel reason: %#04x\n", reason);274 return SDTX_UNKNOWN(reason);275 }276}277 278 279/* -- IOCTLs. --------------------------------------------------------------- */280 281static int sdtx_ioctl_get_base_info(struct sdtx_device *ddev,282 struct sdtx_base_info __user *buf)283{284 struct ssam_bas_base_info raw;285 struct sdtx_base_info info;286 int status;287 288 lockdep_assert_held_read(&ddev->lock);289 290 status = ssam_retry(ssam_bas_get_base, ddev->ctrl, &raw);291 if (status < 0)292 return status;293 294 info.state = sdtx_translate_base_state(ddev, raw.state);295 info.base_id = SDTX_BASE_TYPE_SSH(raw.base_id);296 297 if (copy_to_user(buf, &info, sizeof(info)))298 return -EFAULT;299 300 return 0;301}302 303static int sdtx_ioctl_get_device_mode(struct sdtx_device *ddev, u16 __user *buf)304{305 u8 mode;306 int status;307 308 lockdep_assert_held_read(&ddev->lock);309 310 status = ssam_retry(ssam_bas_get_device_mode, ddev->ctrl, &mode);311 if (status < 0)312 return status;313 314 return put_user(mode, buf);315}316 317static int sdtx_ioctl_get_latch_status(struct sdtx_device *ddev, u16 __user *buf)318{319 u8 latch;320 int status;321 322 lockdep_assert_held_read(&ddev->lock);323 324 status = ssam_retry(ssam_bas_get_latch_status, ddev->ctrl, &latch);325 if (status < 0)326 return status;327 328 return put_user(sdtx_translate_latch_status(ddev, latch), buf);329}330 331static long __surface_dtx_ioctl(struct sdtx_client *client, unsigned int cmd, unsigned long arg)332{333 struct sdtx_device *ddev = client->ddev;334 335 lockdep_assert_held_read(&ddev->lock);336 337 switch (cmd) {338 case SDTX_IOCTL_EVENTS_ENABLE:339 set_bit(SDTX_CLIENT_EVENTS_ENABLED_BIT, &client->flags);340 return 0;341 342 case SDTX_IOCTL_EVENTS_DISABLE:343 clear_bit(SDTX_CLIENT_EVENTS_ENABLED_BIT, &client->flags);344 return 0;345 346 case SDTX_IOCTL_LATCH_LOCK:347 return ssam_retry(ssam_bas_latch_lock, ddev->ctrl);348 349 case SDTX_IOCTL_LATCH_UNLOCK:350 return ssam_retry(ssam_bas_latch_unlock, ddev->ctrl);351 352 case SDTX_IOCTL_LATCH_REQUEST:353 return ssam_retry(ssam_bas_latch_request, ddev->ctrl);354 355 case SDTX_IOCTL_LATCH_CONFIRM:356 return ssam_retry(ssam_bas_latch_confirm, ddev->ctrl);357 358 case SDTX_IOCTL_LATCH_HEARTBEAT:359 return ssam_retry(ssam_bas_latch_heartbeat, ddev->ctrl);360 361 case SDTX_IOCTL_LATCH_CANCEL:362 return ssam_retry(ssam_bas_latch_cancel, ddev->ctrl);363 364 case SDTX_IOCTL_GET_BASE_INFO:365 return sdtx_ioctl_get_base_info(ddev, (struct sdtx_base_info __user *)arg);366 367 case SDTX_IOCTL_GET_DEVICE_MODE:368 return sdtx_ioctl_get_device_mode(ddev, (u16 __user *)arg);369 370 case SDTX_IOCTL_GET_LATCH_STATUS:371 return sdtx_ioctl_get_latch_status(ddev, (u16 __user *)arg);372 373 default:374 return -EINVAL;375 }376}377 378static long surface_dtx_ioctl(struct file *file, unsigned int cmd, unsigned long arg)379{380 struct sdtx_client *client = file->private_data;381 long status;382 383 if (down_read_killable(&client->ddev->lock))384 return -ERESTARTSYS;385 386 if (test_bit(SDTX_DEVICE_SHUTDOWN_BIT, &client->ddev->flags)) {387 up_read(&client->ddev->lock);388 return -ENODEV;389 }390 391 status = __surface_dtx_ioctl(client, cmd, arg);392 393 up_read(&client->ddev->lock);394 return status;395}396 397 398/* -- File operations. ------------------------------------------------------ */399 400static int surface_dtx_open(struct inode *inode, struct file *file)401{402 struct sdtx_device *ddev = container_of(file->private_data, struct sdtx_device, mdev);403 struct sdtx_client *client;404 405 /* Initialize client. */406 client = kzalloc(sizeof(*client), GFP_KERNEL);407 if (!client)408 return -ENOMEM;409 410 client->ddev = sdtx_device_get(ddev);411 412 INIT_LIST_HEAD(&client->node);413 414 mutex_init(&client->read_lock);415 INIT_KFIFO(client->buffer);416 417 file->private_data = client;418 419 /* Attach client. */420 down_write(&ddev->client_lock);421 422 /*423 * Do not add a new client if the device has been shut down. Note that424 * it's enough to hold the client_lock here as, during shutdown, we425 * only acquire that lock and remove clients after marking the device426 * as shut down.427 */428 if (test_bit(SDTX_DEVICE_SHUTDOWN_BIT, &ddev->flags)) {429 up_write(&ddev->client_lock);430 mutex_destroy(&client->read_lock);431 sdtx_device_put(client->ddev);432 kfree(client);433 return -ENODEV;434 }435 436 list_add_tail(&client->node, &ddev->client_list);437 up_write(&ddev->client_lock);438 439 stream_open(inode, file);440 return 0;441}442 443static int surface_dtx_release(struct inode *inode, struct file *file)444{445 struct sdtx_client *client = file->private_data;446 447 /* Detach client. */448 down_write(&client->ddev->client_lock);449 list_del(&client->node);450 up_write(&client->ddev->client_lock);451 452 /* Free client. */453 sdtx_device_put(client->ddev);454 mutex_destroy(&client->read_lock);455 kfree(client);456 457 return 0;458}459 460static ssize_t surface_dtx_read(struct file *file, char __user *buf, size_t count, loff_t *offs)461{462 struct sdtx_client *client = file->private_data;463 struct sdtx_device *ddev = client->ddev;464 unsigned int copied;465 int status = 0;466 467 if (down_read_killable(&ddev->lock))468 return -ERESTARTSYS;469 470 /* Make sure we're not shut down. */471 if (test_bit(SDTX_DEVICE_SHUTDOWN_BIT, &ddev->flags)) {472 up_read(&ddev->lock);473 return -ENODEV;474 }475 476 do {477 /* Check availability, wait if necessary. */478 if (kfifo_is_empty(&client->buffer)) {479 up_read(&ddev->lock);480 481 if (file->f_flags & O_NONBLOCK)482 return -EAGAIN;483 484 status = wait_event_interruptible(ddev->waitq,485 !kfifo_is_empty(&client->buffer) ||486 test_bit(SDTX_DEVICE_SHUTDOWN_BIT,487 &ddev->flags));488 if (status < 0)489 return status;490 491 if (down_read_killable(&ddev->lock))492 return -ERESTARTSYS;493 494 /* Need to check that we're not shut down again. */495 if (test_bit(SDTX_DEVICE_SHUTDOWN_BIT, &ddev->flags)) {496 up_read(&ddev->lock);497 return -ENODEV;498 }499 }500 501 /* Try to read from FIFO. */502 if (mutex_lock_interruptible(&client->read_lock)) {503 up_read(&ddev->lock);504 return -ERESTARTSYS;505 }506 507 status = kfifo_to_user(&client->buffer, buf, count, &copied);508 mutex_unlock(&client->read_lock);509 510 if (status < 0) {511 up_read(&ddev->lock);512 return status;513 }514 515 /* We might not have gotten anything, check this here. */516 if (copied == 0 && (file->f_flags & O_NONBLOCK)) {517 up_read(&ddev->lock);518 return -EAGAIN;519 }520 } while (copied == 0);521 522 up_read(&ddev->lock);523 return copied;524}525 526static __poll_t surface_dtx_poll(struct file *file, struct poll_table_struct *pt)527{528 struct sdtx_client *client = file->private_data;529 __poll_t events = 0;530 531 if (test_bit(SDTX_DEVICE_SHUTDOWN_BIT, &client->ddev->flags))532 return EPOLLHUP | EPOLLERR;533 534 poll_wait(file, &client->ddev->waitq, pt);535 536 if (!kfifo_is_empty(&client->buffer))537 events |= EPOLLIN | EPOLLRDNORM;538 539 return events;540}541 542static int surface_dtx_fasync(int fd, struct file *file, int on)543{544 struct sdtx_client *client = file->private_data;545 546 return fasync_helper(fd, file, on, &client->fasync);547}548 549static const struct file_operations surface_dtx_fops = {550 .owner = THIS_MODULE,551 .open = surface_dtx_open,552 .release = surface_dtx_release,553 .read = surface_dtx_read,554 .poll = surface_dtx_poll,555 .fasync = surface_dtx_fasync,556 .unlocked_ioctl = surface_dtx_ioctl,557 .compat_ioctl = surface_dtx_ioctl,558};559 560 561/* -- Event handling/forwarding. -------------------------------------------- */562 563/*564 * The device operation mode is not immediately updated on the EC when the565 * base has been connected, i.e. querying the device mode inside the566 * connection event callback yields an outdated value. Thus, we can only567 * determine the new tablet-mode switch and device mode values after some568 * time.569 *570 * These delays have been chosen by experimenting. We first delay on connect571 * events, then check and validate the device mode against the base state and572 * if invalid delay again by the "recheck" delay.573 */574#define SDTX_DEVICE_MODE_DELAY_CONNECT msecs_to_jiffies(100)575#define SDTX_DEVICE_MODE_DELAY_RECHECK msecs_to_jiffies(100)576 577struct sdtx_status_event {578 struct sdtx_event e;579 __u16 v;580} __packed;581 582struct sdtx_base_info_event {583 struct sdtx_event e;584 struct sdtx_base_info v;585} __packed;586 587union sdtx_generic_event {588 struct sdtx_event common;589 struct sdtx_status_event status;590 struct sdtx_base_info_event base;591};592 593static void sdtx_update_device_mode(struct sdtx_device *ddev, unsigned long delay);594 595/* Must be executed with ddev->write_lock held. */596static void sdtx_push_event(struct sdtx_device *ddev, struct sdtx_event *evt)597{598 const size_t len = sizeof(struct sdtx_event) + evt->length;599 struct sdtx_client *client;600 601 lockdep_assert_held(&ddev->write_lock);602 603 down_read(&ddev->client_lock);604 list_for_each_entry(client, &ddev->client_list, node) {605 if (!test_bit(SDTX_CLIENT_EVENTS_ENABLED_BIT, &client->flags))606 continue;607 608 if (likely(kfifo_avail(&client->buffer) >= len))609 kfifo_in(&client->buffer, (const u8 *)evt, len);610 else611 dev_warn(ddev->dev, "event buffer overrun\n");612 613 kill_fasync(&client->fasync, SIGIO, POLL_IN);614 }615 up_read(&ddev->client_lock);616 617 wake_up_interruptible(&ddev->waitq);618}619 620static u32 sdtx_notifier(struct ssam_event_notifier *nf, const struct ssam_event *in)621{622 struct sdtx_device *ddev = container_of(nf, struct sdtx_device, notif);623 union sdtx_generic_event event;624 size_t len;625 626 /* Validate event payload length. */627 switch (in->command_id) {628 case SAM_EVENT_CID_DTX_CONNECTION:629 len = 2 * sizeof(u8);630 break;631 632 case SAM_EVENT_CID_DTX_REQUEST:633 len = 0;634 break;635 636 case SAM_EVENT_CID_DTX_CANCEL:637 len = sizeof(u8);638 break;639 640 case SAM_EVENT_CID_DTX_LATCH_STATUS:641 len = sizeof(u8);642 break;643 644 default:645 return 0;646 }647 648 if (in->length != len) {649 dev_err(ddev->dev,650 "unexpected payload size for event %#04x: got %u, expected %zu\n",651 in->command_id, in->length, len);652 return 0;653 }654 655 mutex_lock(&ddev->write_lock);656 657 /* Translate event. */658 switch (in->command_id) {659 case SAM_EVENT_CID_DTX_CONNECTION:660 clear_bit(SDTX_DEVICE_DIRTY_BASE_BIT, &ddev->flags);661 662 /* If state has not changed: do not send new event. */663 if (ddev->state.base.state == in->data[0] &&664 ddev->state.base.base_id == in->data[1])665 goto out;666 667 ddev->state.base.state = in->data[0];668 ddev->state.base.base_id = in->data[1];669 670 event.base.e.length = sizeof(struct sdtx_base_info);671 event.base.e.code = SDTX_EVENT_BASE_CONNECTION;672 event.base.v.state = sdtx_translate_base_state(ddev, in->data[0]);673 event.base.v.base_id = SDTX_BASE_TYPE_SSH(in->data[1]);674 break;675 676 case SAM_EVENT_CID_DTX_REQUEST:677 event.common.code = SDTX_EVENT_REQUEST;678 event.common.length = 0;679 break;680 681 case SAM_EVENT_CID_DTX_CANCEL:682 event.status.e.length = sizeof(u16);683 event.status.e.code = SDTX_EVENT_CANCEL;684 event.status.v = sdtx_translate_cancel_reason(ddev, in->data[0]);685 break;686 687 case SAM_EVENT_CID_DTX_LATCH_STATUS:688 clear_bit(SDTX_DEVICE_DIRTY_LATCH_BIT, &ddev->flags);689 690 /* If state has not changed: do not send new event. */691 if (ddev->state.latch_status == in->data[0])692 goto out;693 694 ddev->state.latch_status = in->data[0];695 696 event.status.e.length = sizeof(u16);697 event.status.e.code = SDTX_EVENT_LATCH_STATUS;698 event.status.v = sdtx_translate_latch_status(ddev, in->data[0]);699 break;700 }701 702 sdtx_push_event(ddev, &event.common);703 704 /* Update device mode on base connection change. */705 if (in->command_id == SAM_EVENT_CID_DTX_CONNECTION) {706 unsigned long delay;707 708 delay = in->data[0] ? SDTX_DEVICE_MODE_DELAY_CONNECT : 0;709 sdtx_update_device_mode(ddev, delay);710 }711 712out:713 mutex_unlock(&ddev->write_lock);714 return SSAM_NOTIF_HANDLED;715}716 717 718/* -- State update functions. ----------------------------------------------- */719 720static bool sdtx_device_mode_invalid(u8 mode, u8 base_state)721{722 return ((base_state == SSAM_BAS_BASE_STATE_ATTACHED) &&723 (mode == SDTX_DEVICE_MODE_TABLET)) ||724 ((base_state == SSAM_BAS_BASE_STATE_DETACH_SUCCESS) &&725 (mode != SDTX_DEVICE_MODE_TABLET));726}727 728static void sdtx_device_mode_workfn(struct work_struct *work)729{730 struct sdtx_device *ddev = container_of(work, struct sdtx_device, mode_work.work);731 struct sdtx_status_event event;732 struct ssam_bas_base_info base;733 int status, tablet;734 u8 mode;735 736 /* Get operation mode. */737 status = ssam_retry(ssam_bas_get_device_mode, ddev->ctrl, &mode);738 if (status) {739 dev_err(ddev->dev, "failed to get device mode: %d\n", status);740 return;741 }742 743 /* Get base info. */744 status = ssam_retry(ssam_bas_get_base, ddev->ctrl, &base);745 if (status) {746 dev_err(ddev->dev, "failed to get base info: %d\n", status);747 return;748 }749 750 /*751 * In some cases (specifically when attaching the base), the device752 * mode isn't updated right away. Thus we check if the device mode753 * makes sense for the given base state and try again later if it754 * doesn't.755 */756 if (sdtx_device_mode_invalid(mode, base.state)) {757 dev_dbg(ddev->dev, "device mode is invalid, trying again\n");758 sdtx_update_device_mode(ddev, SDTX_DEVICE_MODE_DELAY_RECHECK);759 return;760 }761 762 mutex_lock(&ddev->write_lock);763 clear_bit(SDTX_DEVICE_DIRTY_MODE_BIT, &ddev->flags);764 765 /* Avoid sending duplicate device-mode events. */766 if (ddev->state.device_mode == mode) {767 mutex_unlock(&ddev->write_lock);768 return;769 }770 771 ddev->state.device_mode = mode;772 773 event.e.length = sizeof(u16);774 event.e.code = SDTX_EVENT_DEVICE_MODE;775 event.v = mode;776 777 sdtx_push_event(ddev, &event.e);778 779 /* Send SW_TABLET_MODE event. */780 tablet = mode != SDTX_DEVICE_MODE_LAPTOP;781 input_report_switch(ddev->mode_switch, SW_TABLET_MODE, tablet);782 input_sync(ddev->mode_switch);783 784 mutex_unlock(&ddev->write_lock);785}786 787static void sdtx_update_device_mode(struct sdtx_device *ddev, unsigned long delay)788{789 schedule_delayed_work(&ddev->mode_work, delay);790}791 792/* Must be executed with ddev->write_lock held. */793static void __sdtx_device_state_update_base(struct sdtx_device *ddev,794 struct ssam_bas_base_info info)795{796 struct sdtx_base_info_event event;797 798 lockdep_assert_held(&ddev->write_lock);799 800 /* Prevent duplicate events. */801 if (ddev->state.base.state == info.state &&802 ddev->state.base.base_id == info.base_id)803 return;804 805 ddev->state.base = info;806 807 event.e.length = sizeof(struct sdtx_base_info);808 event.e.code = SDTX_EVENT_BASE_CONNECTION;809 event.v.state = sdtx_translate_base_state(ddev, info.state);810 event.v.base_id = SDTX_BASE_TYPE_SSH(info.base_id);811 812 sdtx_push_event(ddev, &event.e);813}814 815/* Must be executed with ddev->write_lock held. */816static void __sdtx_device_state_update_mode(struct sdtx_device *ddev, u8 mode)817{818 struct sdtx_status_event event;819 int tablet;820 821 /*822 * Note: This function must be called after updating the base state823 * via __sdtx_device_state_update_base(), as we rely on the updated824 * base state value in the validity check below.825 */826 827 lockdep_assert_held(&ddev->write_lock);828 829 if (sdtx_device_mode_invalid(mode, ddev->state.base.state)) {830 dev_dbg(ddev->dev, "device mode is invalid, trying again\n");831 sdtx_update_device_mode(ddev, SDTX_DEVICE_MODE_DELAY_RECHECK);832 return;833 }834 835 /* Prevent duplicate events. */836 if (ddev->state.device_mode == mode)837 return;838 839 ddev->state.device_mode = mode;840 841 /* Send event. */842 event.e.length = sizeof(u16);843 event.e.code = SDTX_EVENT_DEVICE_MODE;844 event.v = mode;845 846 sdtx_push_event(ddev, &event.e);847 848 /* Send SW_TABLET_MODE event. */849 tablet = mode != SDTX_DEVICE_MODE_LAPTOP;850 input_report_switch(ddev->mode_switch, SW_TABLET_MODE, tablet);851 input_sync(ddev->mode_switch);852}853 854/* Must be executed with ddev->write_lock held. */855static void __sdtx_device_state_update_latch(struct sdtx_device *ddev, u8 status)856{857 struct sdtx_status_event event;858 859 lockdep_assert_held(&ddev->write_lock);860 861 /* Prevent duplicate events. */862 if (ddev->state.latch_status == status)863 return;864 865 ddev->state.latch_status = status;866 867 event.e.length = sizeof(struct sdtx_base_info);868 event.e.code = SDTX_EVENT_BASE_CONNECTION;869 event.v = sdtx_translate_latch_status(ddev, status);870 871 sdtx_push_event(ddev, &event.e);872}873 874static void sdtx_device_state_workfn(struct work_struct *work)875{876 struct sdtx_device *ddev = container_of(work, struct sdtx_device, state_work.work);877 struct ssam_bas_base_info base;878 u8 mode, latch;879 int status;880 881 /* Mark everything as dirty. */882 set_bit(SDTX_DEVICE_DIRTY_BASE_BIT, &ddev->flags);883 set_bit(SDTX_DEVICE_DIRTY_MODE_BIT, &ddev->flags);884 set_bit(SDTX_DEVICE_DIRTY_LATCH_BIT, &ddev->flags);885 886 /*887 * Ensure that the state gets marked as dirty before continuing to888 * query it. Necessary to ensure that clear_bit() calls in889 * sdtx_notifier() and sdtx_device_mode_workfn() actually clear these890 * bits if an event is received while updating the state here.891 */892 smp_mb__after_atomic();893 894 status = ssam_retry(ssam_bas_get_base, ddev->ctrl, &base);895 if (status) {896 dev_err(ddev->dev, "failed to get base state: %d\n", status);897 return;898 }899 900 status = ssam_retry(ssam_bas_get_device_mode, ddev->ctrl, &mode);901 if (status) {902 dev_err(ddev->dev, "failed to get device mode: %d\n", status);903 return;904 }905 906 status = ssam_retry(ssam_bas_get_latch_status, ddev->ctrl, &latch);907 if (status) {908 dev_err(ddev->dev, "failed to get latch status: %d\n", status);909 return;910 }911 912 mutex_lock(&ddev->write_lock);913 914 /*915 * If the respective dirty-bit has been cleared, an event has been916 * received, updating this state. The queried state may thus be out of917 * date. At this point, we can safely assume that the state provided918 * by the event is either up to date, or we're about to receive919 * another event updating it.920 */921 922 if (test_and_clear_bit(SDTX_DEVICE_DIRTY_BASE_BIT, &ddev->flags))923 __sdtx_device_state_update_base(ddev, base);924 925 if (test_and_clear_bit(SDTX_DEVICE_DIRTY_MODE_BIT, &ddev->flags))926 __sdtx_device_state_update_mode(ddev, mode);927 928 if (test_and_clear_bit(SDTX_DEVICE_DIRTY_LATCH_BIT, &ddev->flags))929 __sdtx_device_state_update_latch(ddev, latch);930 931 mutex_unlock(&ddev->write_lock);932}933 934static void sdtx_update_device_state(struct sdtx_device *ddev, unsigned long delay)935{936 schedule_delayed_work(&ddev->state_work, delay);937}938 939 940/* -- Common device initialization. ----------------------------------------- */941 942static int sdtx_device_init(struct sdtx_device *ddev, struct device *dev,943 struct ssam_controller *ctrl)944{945 int status, tablet_mode;946 947 /* Basic initialization. */948 kref_init(&ddev->kref);949 init_rwsem(&ddev->lock);950 ddev->dev = dev;951 ddev->ctrl = ctrl;952 953 ddev->mdev.minor = MISC_DYNAMIC_MINOR;954 ddev->mdev.name = "surface_dtx";955 ddev->mdev.nodename = "surface/dtx";956 ddev->mdev.fops = &surface_dtx_fops;957 958 ddev->notif.base.priority = 1;959 ddev->notif.base.fn = sdtx_notifier;960 ddev->notif.event.reg = SSAM_EVENT_REGISTRY_SAM;961 ddev->notif.event.id.target_category = SSAM_SSH_TC_BAS;962 ddev->notif.event.id.instance = 0;963 ddev->notif.event.mask = SSAM_EVENT_MASK_NONE;964 ddev->notif.event.flags = SSAM_EVENT_SEQUENCED;965 966 init_waitqueue_head(&ddev->waitq);967 mutex_init(&ddev->write_lock);968 init_rwsem(&ddev->client_lock);969 INIT_LIST_HEAD(&ddev->client_list);970 971 INIT_DELAYED_WORK(&ddev->mode_work, sdtx_device_mode_workfn);972 INIT_DELAYED_WORK(&ddev->state_work, sdtx_device_state_workfn);973 974 /*975 * Get current device state. We want to guarantee that events are only976 * sent when state actually changes. Thus we cannot use special977 * "uninitialized" values, as that would cause problems when manually978 * querying the state in surface_dtx_pm_complete(). I.e. we would not979 * be able to detect state changes there if no change event has been980 * received between driver initialization and first device suspension.981 *982 * Note that we also need to do this before registering the event983 * notifier, as that may access the state values.984 */985 status = ssam_retry(ssam_bas_get_base, ddev->ctrl, &ddev->state.base);986 if (status)987 return status;988 989 status = ssam_retry(ssam_bas_get_device_mode, ddev->ctrl, &ddev->state.device_mode);990 if (status)991 return status;992 993 status = ssam_retry(ssam_bas_get_latch_status, ddev->ctrl, &ddev->state.latch_status);994 if (status)995 return status;996 997 /* Set up tablet mode switch. */998 ddev->mode_switch = input_allocate_device();999 if (!ddev->mode_switch)1000 return -ENOMEM;1001 1002 ddev->mode_switch->name = "Microsoft Surface DTX Device Mode Switch";1003 ddev->mode_switch->phys = "ssam/01:11:01:00:00/input0";1004 ddev->mode_switch->id.bustype = BUS_HOST;1005 ddev->mode_switch->dev.parent = ddev->dev;1006 1007 tablet_mode = (ddev->state.device_mode != SDTX_DEVICE_MODE_LAPTOP);1008 input_set_capability(ddev->mode_switch, EV_SW, SW_TABLET_MODE);1009 input_report_switch(ddev->mode_switch, SW_TABLET_MODE, tablet_mode);1010 1011 status = input_register_device(ddev->mode_switch);1012 if (status) {1013 input_free_device(ddev->mode_switch);1014 return status;1015 }1016 1017 /* Set up event notifier. */1018 status = ssam_notifier_register(ddev->ctrl, &ddev->notif);1019 if (status)1020 goto err_notif;1021 1022 /* Register miscdevice. */1023 status = misc_register(&ddev->mdev);1024 if (status)1025 goto err_mdev;1026 1027 /*1028 * Update device state in case it has changed between getting the1029 * initial mode and registering the event notifier.1030 */1031 sdtx_update_device_state(ddev, 0);1032 return 0;1033 1034err_notif:1035 ssam_notifier_unregister(ddev->ctrl, &ddev->notif);1036 cancel_delayed_work_sync(&ddev->mode_work);1037err_mdev:1038 input_unregister_device(ddev->mode_switch);1039 return status;1040}1041 1042static struct sdtx_device *sdtx_device_create(struct device *dev, struct ssam_controller *ctrl)1043{1044 struct sdtx_device *ddev;1045 int status;1046 1047 ddev = kzalloc(sizeof(*ddev), GFP_KERNEL);1048 if (!ddev)1049 return ERR_PTR(-ENOMEM);1050 1051 status = sdtx_device_init(ddev, dev, ctrl);1052 if (status) {1053 sdtx_device_put(ddev);1054 return ERR_PTR(status);1055 }1056 1057 return ddev;1058}1059 1060static void sdtx_device_destroy(struct sdtx_device *ddev)1061{1062 struct sdtx_client *client;1063 1064 /*1065 * Mark device as shut-down. Prevent new clients from being added and1066 * new operations from being executed.1067 */1068 set_bit(SDTX_DEVICE_SHUTDOWN_BIT, &ddev->flags);1069 1070 /* Disable notifiers, prevent new events from arriving. */1071 ssam_notifier_unregister(ddev->ctrl, &ddev->notif);1072 1073 /* Stop mode_work, prevent access to mode_switch. */1074 cancel_delayed_work_sync(&ddev->mode_work);1075 1076 /* Stop state_work. */1077 cancel_delayed_work_sync(&ddev->state_work);1078 1079 /* With mode_work canceled, we can unregister the mode_switch. */1080 input_unregister_device(ddev->mode_switch);1081 1082 /* Wake up async clients. */1083 down_write(&ddev->client_lock);1084 list_for_each_entry(client, &ddev->client_list, node) {1085 kill_fasync(&client->fasync, SIGIO, POLL_HUP);1086 }1087 up_write(&ddev->client_lock);1088 1089 /* Wake up blocking clients. */1090 wake_up_interruptible(&ddev->waitq);1091 1092 /*1093 * Wait for clients to finish their current operation. After this, the1094 * controller and device references are guaranteed to be no longer in1095 * use.1096 */1097 down_write(&ddev->lock);1098 ddev->dev = NULL;1099 ddev->ctrl = NULL;1100 up_write(&ddev->lock);1101 1102 /* Finally remove the misc-device. */1103 misc_deregister(&ddev->mdev);1104 1105 /*1106 * We're now guaranteed that sdtx_device_open() won't be called any1107 * more, so we can now drop out reference.1108 */1109 sdtx_device_put(ddev);1110}1111 1112 1113/* -- PM ops. --------------------------------------------------------------- */1114 1115#ifdef CONFIG_PM_SLEEP1116 1117static void surface_dtx_pm_complete(struct device *dev)1118{1119 struct sdtx_device *ddev = dev_get_drvdata(dev);1120 1121 /*1122 * Normally, the EC will store events while suspended (i.e. in1123 * display-off state) and release them when resumed (i.e. transitioned1124 * to display-on state). During hibernation, however, the EC will be1125 * shut down and does not store events. Furthermore, events might be1126 * dropped during prolonged suspension (it is currently unknown how1127 * big this event buffer is and how it behaves on overruns).1128 *1129 * To prevent any problems, we update the device state here. We do1130 * this delayed to ensure that any events sent by the EC directly1131 * after resuming will be handled first. The delay below has been1132 * chosen (experimentally), so that there should be ample time for1133 * these events to be handled, before we check and, if necessary,1134 * update the state.1135 */1136 sdtx_update_device_state(ddev, msecs_to_jiffies(1000));1137}1138 1139static const struct dev_pm_ops surface_dtx_pm_ops = {1140 .complete = surface_dtx_pm_complete,1141};1142 1143#else /* CONFIG_PM_SLEEP */1144 1145static const struct dev_pm_ops surface_dtx_pm_ops = {};1146 1147#endif /* CONFIG_PM_SLEEP */1148 1149 1150/* -- Platform driver. ------------------------------------------------------ */1151 1152static int surface_dtx_platform_probe(struct platform_device *pdev)1153{1154 struct ssam_controller *ctrl;1155 struct sdtx_device *ddev;1156 1157 /* Link to EC. */1158 ctrl = ssam_client_bind(&pdev->dev);1159 if (IS_ERR(ctrl))1160 return PTR_ERR(ctrl) == -ENODEV ? -EPROBE_DEFER : PTR_ERR(ctrl);1161 1162 ddev = sdtx_device_create(&pdev->dev, ctrl);1163 if (IS_ERR(ddev))1164 return PTR_ERR(ddev);1165 1166 platform_set_drvdata(pdev, ddev);1167 return 0;1168}1169 1170static void surface_dtx_platform_remove(struct platform_device *pdev)1171{1172 sdtx_device_destroy(platform_get_drvdata(pdev));1173}1174 1175static const struct acpi_device_id surface_dtx_acpi_match[] = {1176 { "MSHW0133", 0 },1177 { },1178};1179MODULE_DEVICE_TABLE(acpi, surface_dtx_acpi_match);1180 1181static struct platform_driver surface_dtx_platform_driver = {1182 .probe = surface_dtx_platform_probe,1183 .remove_new = surface_dtx_platform_remove,1184 .driver = {1185 .name = "surface_dtx_pltf",1186 .acpi_match_table = surface_dtx_acpi_match,1187 .pm = &surface_dtx_pm_ops,1188 .probe_type = PROBE_PREFER_ASYNCHRONOUS,1189 },1190};1191 1192 1193/* -- SSAM device driver. --------------------------------------------------- */1194 1195#ifdef CONFIG_SURFACE_AGGREGATOR_BUS1196 1197static int surface_dtx_ssam_probe(struct ssam_device *sdev)1198{1199 struct sdtx_device *ddev;1200 1201 ddev = sdtx_device_create(&sdev->dev, sdev->ctrl);1202 if (IS_ERR(ddev))1203 return PTR_ERR(ddev);1204 1205 ssam_device_set_drvdata(sdev, ddev);1206 return 0;1207}1208 1209static void surface_dtx_ssam_remove(struct ssam_device *sdev)1210{1211 sdtx_device_destroy(ssam_device_get_drvdata(sdev));1212}1213 1214static const struct ssam_device_id surface_dtx_ssam_match[] = {1215 { SSAM_SDEV(BAS, SAM, 0x00, 0x00) },1216 { },1217};1218MODULE_DEVICE_TABLE(ssam, surface_dtx_ssam_match);1219 1220static struct ssam_device_driver surface_dtx_ssam_driver = {1221 .probe = surface_dtx_ssam_probe,1222 .remove = surface_dtx_ssam_remove,1223 .match_table = surface_dtx_ssam_match,1224 .driver = {1225 .name = "surface_dtx",1226 .pm = &surface_dtx_pm_ops,1227 .probe_type = PROBE_PREFER_ASYNCHRONOUS,1228 },1229};1230 1231static int ssam_dtx_driver_register(void)1232{1233 return ssam_device_driver_register(&surface_dtx_ssam_driver);1234}1235 1236static void ssam_dtx_driver_unregister(void)1237{1238 ssam_device_driver_unregister(&surface_dtx_ssam_driver);1239}1240 1241#else /* CONFIG_SURFACE_AGGREGATOR_BUS */1242 1243static int ssam_dtx_driver_register(void)1244{1245 return 0;1246}1247 1248static void ssam_dtx_driver_unregister(void)1249{1250}1251 1252#endif /* CONFIG_SURFACE_AGGREGATOR_BUS */1253 1254 1255/* -- Module setup. --------------------------------------------------------- */1256 1257static int __init surface_dtx_init(void)1258{1259 int status;1260 1261 status = ssam_dtx_driver_register();1262 if (status)1263 return status;1264 1265 status = platform_driver_register(&surface_dtx_platform_driver);1266 if (status)1267 ssam_dtx_driver_unregister();1268 1269 return status;1270}1271module_init(surface_dtx_init);1272 1273static void __exit surface_dtx_exit(void)1274{1275 platform_driver_unregister(&surface_dtx_platform_driver);1276 ssam_dtx_driver_unregister();1277}1278module_exit(surface_dtx_exit);1279 1280MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");1281MODULE_DESCRIPTION("Detachment-system driver for Surface System Aggregator Module");1282MODULE_LICENSE("GPL");1283