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 <LeoLi@freescale.com> 8 * Jerry Huang <Chang-Ming.Huang@freescale.com> 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"); 449