drivers/usb/common/usb-otg-fsm.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * OTG Finite State Machine from OTG spec
   4  *
   5  * Copyright (C) 2007,2008 Freescale Semiconductor, Inc.
   6  *
   7  * Author:      Li Yang <[email protected]>
   8  *              Jerry Huang <[email protected]>
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/types.h>
  14 #include <linux/mutex.h>
  15 #include <linux/delay.h>
  16 #include <linux/usb.h>
  17 #include <linux/usb/gadget.h>
  18 #include <linux/usb/otg.h>
  19 #include <linux/usb/otg-fsm.h>
  20
  21 #ifdef VERBOSE
  22 #define VDBG(fmt, args...) pr_debug("[%s]  " fmt, \
  23                                  __func__, ## args)
  24 #else
  25 #define VDBG(stuff...)  do {} while (0)
  26 #endif
  27
  28 /* Change USB protocol when there is a protocol change */
  29 static int otg_set_protocol(struct otg_fsm *fsm, int protocol)
  30 {
  31         int ret = 0;
  32
  33         if (fsm->protocol != protocol) {
  34                 VDBG("Changing role fsm->protocol= %d; new protocol= %d\n",
  35                         fsm->protocol, protocol);
  36                 /* stop old protocol */
  37                 if (fsm->protocol == PROTO_HOST)
  38                         ret = otg_start_host(fsm, 0);
  39                 else if (fsm->protocol == PROTO_GADGET)
  40                         ret = otg_start_gadget(fsm, 0);
  41                 if (ret)
  42                         return ret;
  43
  44                 /* start new protocol */
  45                 if (protocol == PROTO_HOST)
  46                         ret = otg_start_host(fsm, 1);
  47                 else if (protocol == PROTO_GADGET)
  48                         ret = otg_start_gadget(fsm, 1);
  49                 if (ret)
  50                         return ret;
  51
  52                 fsm->protocol = protocol;
  53                 return 0;
  54         }
  55
  56         return 0;
  57 }
  58
  59 /* Called when leaving a state.  Do state clean up jobs here */
  60 static void otg_leave_state(struct otg_fsm *fsm, enum usb_otg_state old_state)
  61 {
  62         switch (old_state) {
  63         case OTG_STATE_B_IDLE:
  64                 otg_del_timer(fsm, B_SE0_SRP);
  65                 fsm->b_se0_srp = 0;
  66                 fsm->adp_sns = 0;
  67                 fsm->adp_prb = 0;
  68                 break;
  69         case OTG_STATE_B_SRP_INIT:
  70                 fsm->data_pulse = 0;
  71                 fsm->b_srp_done = 0;
  72                 break;
  73         case OTG_STATE_B_PERIPHERAL:
  74                 if (fsm->otg->gadget)
  75                         fsm->otg->gadget->host_request_flag = 0;
  76                 break;
  77         case OTG_STATE_B_WAIT_ACON:
  78                 otg_del_timer(fsm, B_ASE0_BRST);
  79                 fsm->b_ase0_brst_tmout = 0;
  80                 break;
  81         case OTG_STATE_B_HOST:
  82                 break;
  83         case OTG_STATE_A_IDLE:
  84                 fsm->adp_prb = 0;
  85                 break;
  86         case OTG_STATE_A_WAIT_VRISE:
  87                 otg_del_timer(fsm, A_WAIT_VRISE);
  88                 fsm->a_wait_vrise_tmout = 0;
  89                 break;
  90         case OTG_STATE_A_WAIT_BCON:
  91                 otg_del_timer(fsm, A_WAIT_BCON);
  92                 fsm->a_wait_bcon_tmout = 0;
  93                 break;
  94         case OTG_STATE_A_HOST:
  95                 otg_del_timer(fsm, A_WAIT_ENUM);
  96                 break;
  97         case OTG_STATE_A_SUSPEND:
  98                 otg_del_timer(fsm, A_AIDL_BDIS);
  99                 fsm->a_aidl_bdis_tmout = 0;
 100                 fsm->a_suspend_req_inf = 0;
 101                 break;
 102         case OTG_STATE_A_PERIPHERAL:
 103                 otg_del_timer(fsm, A_BIDL_ADIS);
 104                 fsm->a_bidl_adis_tmout = 0;
 105                 if (fsm->otg->gadget)
 106                         fsm->otg->gadget->host_request_flag = 0;
 107                 break;
 108         case OTG_STATE_A_WAIT_VFALL:
 109                 otg_del_timer(fsm, A_WAIT_VFALL);
 110                 fsm->a_wait_vfall_tmout = 0;
 111                 otg_del_timer(fsm, A_WAIT_VRISE);
 112                 break;
 113         case OTG_STATE_A_VBUS_ERR:
 114                 break;
 115         default:
 116                 break;
 117         }
 118 }
 119
 120 static void otg_hnp_polling_work(struct work_struct *work)
 121 {
 122         struct otg_fsm *fsm = container_of(to_delayed_work(work),
 123                                 struct otg_fsm, hnp_polling_work);
 124         struct usb_device *udev;
 125         enum usb_otg_state state = fsm->otg->state;
 126         u8 flag;
 127         int retval;
 128
 129         if (state != OTG_STATE_A_HOST && state != OTG_STATE_B_HOST)
 130                 return;
 131
 132         udev = usb_hub_find_child(fsm->otg->host->root_hub, 1);
 133         if (!udev) {
 134                 dev_err(fsm->otg->host->controller,
 135                         "no usb dev connected, can't start HNP polling\n");
 136                 return;
 137         }
 138
 139         *fsm->host_req_flag = 0;
 140         /* Get host request flag from connected USB device */
 141         retval = usb_control_msg(udev,
 142                                 usb_rcvctrlpipe(udev, 0),
 143                                 USB_REQ_GET_STATUS,
 144                                 USB_DIR_IN | USB_RECIP_DEVICE,
 145                                 0,
 146                                 OTG_STS_SELECTOR,
 147                                 fsm->host_req_flag,
 148                                 1,
 149                                 USB_CTRL_GET_TIMEOUT);
 150         if (retval != 1) {
 151                 dev_err(&udev->dev, "Get one byte OTG status failed\n");
 152                 return;
 153         }
 154
 155         flag = *fsm->host_req_flag;
 156         if (flag == 0) {
 157                 /* Continue HNP polling */
 158                 schedule_delayed_work(&fsm->hnp_polling_work,
 159                                         msecs_to_jiffies(T_HOST_REQ_POLL));
 160                 return;
 161         } else if (flag != HOST_REQUEST_FLAG) {
 162                 dev_err(&udev->dev, "host request flag %d is invalid\n", flag);
 163                 return;
 164         }
 165
 166         /* Host request flag is set */
 167         if (state == OTG_STATE_A_HOST) {
 168                 /* Set b_hnp_enable */
 169                 if (!fsm->otg->host->b_hnp_enable) {
 170                         retval = usb_control_msg(udev,
 171                                         usb_sndctrlpipe(udev, 0),
 172                                         USB_REQ_SET_FEATURE, 0,
 173                                         USB_DEVICE_B_HNP_ENABLE,
 174                                         0, NULL, 0,
 175                                         USB_CTRL_SET_TIMEOUT);
 176                         if (retval >= 0)
 177                                 fsm->otg->host->b_hnp_enable = 1;
 178                 }
 179                 fsm->a_bus_req = 0;
 180         } else if (state == OTG_STATE_B_HOST) {
 181                 fsm->b_bus_req = 0;
 182         }
 183
 184         otg_statemachine(fsm);
 185 }
 186
 187 static void otg_start_hnp_polling(struct otg_fsm *fsm)
 188 {
 189         /*
 190          * The memory of host_req_flag should be allocated by
 191          * controller driver, otherwise, hnp polling is not started.
 192          */
 193         if (!fsm->host_req_flag)
 194                 return;
 195
 196         INIT_DELAYED_WORK(&fsm->hnp_polling_work, otg_hnp_polling_work);
 197         schedule_delayed_work(&fsm->hnp_polling_work,
 198                                         msecs_to_jiffies(T_HOST_REQ_POLL));
 199 }
 200
 201 /* Called when entering a state */
 202 static int otg_set_state(struct otg_fsm *fsm, enum usb_otg_state new_state)
 203 {
 204         if (fsm->otg->state == new_state)
 205                 return 0;
 206         VDBG("Set state: %s\n", usb_otg_state_string(new_state));
 207         otg_leave_state(fsm, fsm->otg->state);
 208         switch (new_state) {
 209         case OTG_STATE_B_IDLE:
 210                 otg_drv_vbus(fsm, 0);
 211                 otg_chrg_vbus(fsm, 0);
 212                 otg_loc_conn(fsm, 0);
 213                 otg_loc_sof(fsm, 0);
 214                 /*
 215                  * Driver is responsible for starting ADP probing
 216                  * if ADP sensing times out.
 217                  */
 218                 otg_start_adp_sns(fsm);
 219                 otg_set_protocol(fsm, PROTO_UNDEF);
 220                 otg_add_timer(fsm, B_SE0_SRP);
 221                 break;
 222         case OTG_STATE_B_SRP_INIT:
 223                 otg_start_pulse(fsm);
 224                 otg_loc_sof(fsm, 0);
 225                 otg_set_protocol(fsm, PROTO_UNDEF);
 226                 otg_add_timer(fsm, B_SRP_FAIL);
 227                 break;
 228         case OTG_STATE_B_PERIPHERAL:
 229                 otg_chrg_vbus(fsm, 0);
 230                 otg_loc_sof(fsm, 0);
 231                 otg_set_protocol(fsm, PROTO_GADGET);
 232                 otg_loc_conn(fsm, 1);
 233                 break;
 234         case OTG_STATE_B_WAIT_ACON:
 235                 otg_chrg_vbus(fsm, 0);
 236                 otg_loc_conn(fsm, 0);
 237                 otg_loc_sof(fsm, 0);
 238                 otg_set_protocol(fsm, PROTO_HOST);
 239                 otg_add_timer(fsm, B_ASE0_BRST);
 240                 fsm->a_bus_suspend = 0;
 241                 break;
 242         case OTG_STATE_B_HOST:
 243                 otg_chrg_vbus(fsm, 0);
 244                 otg_loc_conn(fsm, 0);
 245                 otg_loc_sof(fsm, 1);
 246                 otg_set_protocol(fsm, PROTO_HOST);
 247                 usb_bus_start_enum(fsm->otg->host,
 248                                 fsm->otg->host->otg_port);
 249                 otg_start_hnp_polling(fsm);
 250                 break;
 251         case OTG_STATE_A_IDLE:
 252                 otg_drv_vbus(fsm, 0);
 253                 otg_chrg_vbus(fsm, 0);
 254                 otg_loc_conn(fsm, 0);
 255                 otg_loc_sof(fsm, 0);
 256                 otg_start_adp_prb(fsm);
 257                 otg_set_protocol(fsm, PROTO_HOST);
 258                 break;
 259         case OTG_STATE_A_WAIT_VRISE:
 260                 otg_drv_vbus(fsm, 1);
 261                 otg_loc_conn(fsm, 0);
 262                 otg_loc_sof(fsm, 0);
 263                 otg_set_protocol(fsm, PROTO_HOST);
 264                 otg_add_timer(fsm, A_WAIT_VRISE);
 265                 break;
 266         case OTG_STATE_A_WAIT_BCON:
 267                 otg_drv_vbus(fsm, 1);
 268                 otg_loc_conn(fsm, 0);
 269                 otg_loc_sof(fsm, 0);
 270                 otg_set_protocol(fsm, PROTO_HOST);
 271                 otg_add_timer(fsm, A_WAIT_BCON);
 272                 break;
 273         case OTG_STATE_A_HOST:
 274                 otg_drv_vbus(fsm, 1);
 275                 otg_loc_conn(fsm, 0);
 276                 otg_loc_sof(fsm, 1);
 277                 otg_set_protocol(fsm, PROTO_HOST);
 278                 /*
 279                  * When HNP is triggered while a_bus_req = 0, a_host will
 280                  * suspend too fast to complete a_set_b_hnp_en
 281                  */
 282                 if (!fsm->a_bus_req || fsm->a_suspend_req_inf)
 283                         otg_add_timer(fsm, A_WAIT_ENUM);
 284                 otg_start_hnp_polling(fsm);
 285                 break;
 286         case OTG_STATE_A_SUSPEND:
 287                 otg_drv_vbus(fsm, 1);
 288                 otg_loc_conn(fsm, 0);
 289                 otg_loc_sof(fsm, 0);
 290                 otg_set_protocol(fsm, PROTO_HOST);
 291                 otg_add_timer(fsm, A_AIDL_BDIS);
 292
 293                 break;
 294         case OTG_STATE_A_PERIPHERAL:
 295                 otg_loc_sof(fsm, 0);
 296                 otg_set_protocol(fsm, PROTO_GADGET);
 297                 otg_drv_vbus(fsm, 1);
 298                 otg_loc_conn(fsm, 1);
 299                 otg_add_timer(fsm, A_BIDL_ADIS);
 300                 break;
 301         case OTG_STATE_A_WAIT_VFALL:
 302                 otg_drv_vbus(fsm, 0);
 303                 otg_loc_conn(fsm, 0);
 304                 otg_loc_sof(fsm, 0);
 305                 otg_set_protocol(fsm, PROTO_HOST);
 306                 otg_add_timer(fsm, A_WAIT_VFALL);
 307                 break;
 308         case OTG_STATE_A_VBUS_ERR:
 309                 otg_drv_vbus(fsm, 0);
 310                 otg_loc_conn(fsm, 0);
 311                 otg_loc_sof(fsm, 0);
 312                 otg_set_protocol(fsm, PROTO_UNDEF);
 313                 break;
 314         default:
 315                 break;
 316         }
 317
 318         fsm->otg->state = new_state;
 319         fsm->state_changed = 1;
 320         return 0;
 321 }
 322
 323 /* State change judgement */
 324 int otg_statemachine(struct otg_fsm *fsm)
 325 {
 326         enum usb_otg_state state;
 327
 328         mutex_lock(&fsm->lock);
 329
 330         state = fsm->otg->state;
 331         fsm->state_changed = 0;
 332         /* State machine state change judgement */
 333
 334         switch (state) {
 335         case OTG_STATE_UNDEFINED:
 336                 VDBG("fsm->id = %d\n", fsm->id);
 337                 if (fsm->id)
 338                         otg_set_state(fsm, OTG_STATE_B_IDLE);
 339                 else
 340                         otg_set_state(fsm, OTG_STATE_A_IDLE);
 341                 break;
 342         case OTG_STATE_B_IDLE:
 343                 if (!fsm->id)
 344                         otg_set_state(fsm, OTG_STATE_A_IDLE);
 345                 else if (fsm->b_sess_vld && fsm->otg->gadget)
 346                         otg_set_state(fsm, OTG_STATE_B_PERIPHERAL);
 347                 else if ((fsm->b_bus_req || fsm->adp_change || fsm->power_up) &&
 348                                 fsm->b_ssend_srp && fsm->b_se0_srp)
 349                         otg_set_state(fsm, OTG_STATE_B_SRP_INIT);
 350                 break;
 351         case OTG_STATE_B_SRP_INIT:
 352                 if (!fsm->id || fsm->b_srp_done)
 353                         otg_set_state(fsm, OTG_STATE_B_IDLE);
 354                 break;
 355         case OTG_STATE_B_PERIPHERAL:
 356                 if (!fsm->id || !fsm->b_sess_vld)
 357                         otg_set_state(fsm, OTG_STATE_B_IDLE);
 358                 else if (fsm->b_bus_req && fsm->otg->
 359                                 gadget->b_hnp_enable && fsm->a_bus_suspend)
 360                         otg_set_state(fsm, OTG_STATE_B_WAIT_ACON);
 361                 break;
 362         case OTG_STATE_B_WAIT_ACON:
 363                 if (fsm->a_conn)
 364                         otg_set_state(fsm, OTG_STATE_B_HOST);
 365                 else if (!fsm->id || !fsm->b_sess_vld)
 366                         otg_set_state(fsm, OTG_STATE_B_IDLE);
 367                 else if (fsm->a_bus_resume || fsm->b_ase0_brst_tmout) {
 368                         fsm->b_ase0_brst_tmout = 0;
 369                         otg_set_state(fsm, OTG_STATE_B_PERIPHERAL);
 370                 }
 371                 break;
 372         case OTG_STATE_B_HOST:
 373                 if (!fsm->id || !fsm->b_sess_vld)
 374                         otg_set_state(fsm, OTG_STATE_B_IDLE);
 375                 else if (!fsm->b_bus_req || !fsm->a_conn || fsm->test_device)
 376                         otg_set_state(fsm, OTG_STATE_B_PERIPHERAL);
 377                 break;
 378         case OTG_STATE_A_IDLE:
 379                 if (fsm->id)
 380                         otg_set_state(fsm, OTG_STATE_B_IDLE);
 381                 else if (!fsm->a_bus_drop && (fsm->a_bus_req ||
 382                           fsm->a_srp_det || fsm->adp_change || fsm->power_up))
 383                         otg_set_state(fsm, OTG_STATE_A_WAIT_VRISE);
 384                 break;
 385         case OTG_STATE_A_WAIT_VRISE:
 386                 if (fsm->a_vbus_vld)
 387                         otg_set_state(fsm, OTG_STATE_A_WAIT_BCON);
 388                 else if (fsm->id || fsm->a_bus_drop ||
 389                                 fsm->a_wait_vrise_tmout)
 390                         otg_set_state(fsm, OTG_STATE_A_WAIT_VFALL);
 391                 break;
 392         case OTG_STATE_A_WAIT_BCON:
 393                 if (!fsm->a_vbus_vld)
 394                         otg_set_state(fsm, OTG_STATE_A_VBUS_ERR);
 395                 else if (fsm->b_conn)
 396                         otg_set_state(fsm, OTG_STATE_A_HOST);
 397                 else if (fsm->id || fsm->a_bus_drop || fsm->a_wait_bcon_tmout)
 398                         otg_set_state(fsm, OTG_STATE_A_WAIT_VFALL);
 399                 break;
 400         case OTG_STATE_A_HOST:
 401                 if (fsm->id || fsm->a_bus_drop)
 402                         otg_set_state(fsm, OTG_STATE_A_WAIT_VFALL);
 403                 else if ((!fsm->a_bus_req || fsm->a_suspend_req_inf) &&
 404                                 fsm->otg->host->b_hnp_enable)
 405                         otg_set_state(fsm, OTG_STATE_A_SUSPEND);
 406                 else if (!fsm->b_conn)
 407                         otg_set_state(fsm, OTG_STATE_A_WAIT_BCON);
 408                 else if (!fsm->a_vbus_vld)
 409                         otg_set_state(fsm, OTG_STATE_A_VBUS_ERR);
 410                 break;
 411         case OTG_STATE_A_SUSPEND:
 412                 if (!fsm->b_conn && fsm->otg->host->b_hnp_enable)
 413                         otg_set_state(fsm, OTG_STATE_A_PERIPHERAL);
 414                 else if (!fsm->b_conn && !fsm->otg->host->b_hnp_enable)
 415                         otg_set_state(fsm, OTG_STATE_A_WAIT_BCON);
 416                 else if (fsm->a_bus_req || fsm->b_bus_resume)
 417                         otg_set_state(fsm, OTG_STATE_A_HOST);
 418                 else if (fsm->id || fsm->a_bus_drop || fsm->a_aidl_bdis_tmout)
 419                         otg_set_state(fsm, OTG_STATE_A_WAIT_VFALL);
 420                 else if (!fsm->a_vbus_vld)
 421                         otg_set_state(fsm, OTG_STATE_A_VBUS_ERR);
 422                 break;
 423         case OTG_STATE_A_PERIPHERAL:
 424                 if (fsm->id || fsm->a_bus_drop)
 425                         otg_set_state(fsm, OTG_STATE_A_WAIT_VFALL);
 426                 else if (fsm->a_bidl_adis_tmout || fsm->b_bus_suspend)
 427                         otg_set_state(fsm, OTG_STATE_A_WAIT_BCON);
 428                 else if (!fsm->a_vbus_vld)
 429                         otg_set_state(fsm, OTG_STATE_A_VBUS_ERR);
 430                 break;
 431         case OTG_STATE_A_WAIT_VFALL:
 432                 if (fsm->a_wait_vfall_tmout)
 433                         otg_set_state(fsm, OTG_STATE_A_IDLE);
 434                 break;
 435         case OTG_STATE_A_VBUS_ERR:
 436                 if (fsm->id || fsm->a_bus_drop || fsm->a_clr_err)
 437                         otg_set_state(fsm, OTG_STATE_A_WAIT_VFALL);
 438                 break;
 439         default:
 440                 break;
 441         }
 442         mutex_unlock(&fsm->lock);
 443
 444         VDBG("quit statemachine, changed = %d\n", fsm->state_changed);
 445         return fsm->state_changed;
 446 }
 447 EXPORT_SYMBOL_GPL(otg_statemachine);
 448 MODULE_LICENSE("GPL");