usb/common/usb-otg-fsm.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * OTG Finite State Machine from OTG spec
0004  *
0005  * Copyright (C) 2007,2008 Freescale Semiconductor, Inc.
0006  *
0007  * Author:  Li Yang <LeoLi@freescale.com>
0008  *      Jerry Huang <Chang-Ming.Huang@freescale.com>
0009  */
0010
0011 #include <linux/module.h>
0012 #include <linux/kernel.h>
0013 #include <linux/types.h>
0014 #include <linux/mutex.h>
0015 #include <linux/delay.h>
0016 #include <linux/usb.h>
0017 #include <linux/usb/gadget.h>
0018 #include <linux/usb/otg.h>
0019 #include <linux/usb/otg-fsm.h>
0020
0021 #ifdef VERBOSE
0022 #define VDBG(fmt, args...) pr_debug("[%s]  " fmt, \
0023                  __func__, ## args)
0024 #else
0025 #define VDBG(stuff...)  do {} while (0)
0026 #endif
0027
0028 /* Change USB protocol when there is a protocol change */
0029 static int otg_set_protocol(struct otg_fsm *fsm, int protocol)
0030 {
0031     int ret = 0;
0032
0033     if (fsm->protocol != protocol) {
0034         VDBG("Changing role fsm->protocol= %d; new protocol= %d\n",
0035             fsm->protocol, protocol);
0036         /* stop old protocol */
0037         if (fsm->protocol == PROTO_HOST)
0038             ret = otg_start_host(fsm, 0);
0039         else if (fsm->protocol == PROTO_GADGET)
0040             ret = otg_start_gadget(fsm, 0);
0041         if (ret)
0042             return ret;
0043
0044         /* start new protocol */
0045         if (protocol == PROTO_HOST)
0046             ret = otg_start_host(fsm, 1);
0047         else if (protocol == PROTO_GADGET)
0048             ret = otg_start_gadget(fsm, 1);
0049         if (ret)
0050             return ret;
0051
0052         fsm->protocol = protocol;
0053         return 0;
0054     }
0055
0056     return 0;
0057 }
0058
0059 /* Called when leaving a state.  Do state clean up jobs here */
0060 static void otg_leave_state(struct otg_fsm *fsm, enum usb_otg_state old_state)
0061 {
0062     switch (old_state) {
0063     case OTG_STATE_B_IDLE:
0064         otg_del_timer(fsm, B_SE0_SRP);
0065         fsm->b_se0_srp = 0;
0066         fsm->adp_sns = 0;
0067         fsm->adp_prb = 0;
0068         break;
0069     case OTG_STATE_B_SRP_INIT:
0070         fsm->data_pulse = 0;
0071         fsm->b_srp_done = 0;
0072         break;
0073     case OTG_STATE_B_PERIPHERAL:
0074         if (fsm->otg->gadget)
0075             fsm->otg->gadget->host_request_flag = 0;
0076         break;
0077     case OTG_STATE_B_WAIT_ACON:
0078         otg_del_timer(fsm, B_ASE0_BRST);
0079         fsm->b_ase0_brst_tmout = 0;
0080         break;
0081     case OTG_STATE_B_HOST:
0082         break;
0083     case OTG_STATE_A_IDLE:
0084         fsm->adp_prb = 0;
0085         break;
0086     case OTG_STATE_A_WAIT_VRISE:
0087         otg_del_timer(fsm, A_WAIT_VRISE);
0088         fsm->a_wait_vrise_tmout = 0;
0089         break;
0090     case OTG_STATE_A_WAIT_BCON:
0091         otg_del_timer(fsm, A_WAIT_BCON);
0092         fsm->a_wait_bcon_tmout = 0;
0093         break;
0094     case OTG_STATE_A_HOST:
0095         otg_del_timer(fsm, A_WAIT_ENUM);
0096         break;
0097     case OTG_STATE_A_SUSPEND:
0098         otg_del_timer(fsm, A_AIDL_BDIS);
0099         fsm->a_aidl_bdis_tmout = 0;
0100         fsm->a_suspend_req_inf = 0;
0101         break;
0102     case OTG_STATE_A_PERIPHERAL:
0103         otg_del_timer(fsm, A_BIDL_ADIS);
0104         fsm->a_bidl_adis_tmout = 0;
0105         if (fsm->otg->gadget)
0106             fsm->otg->gadget->host_request_flag = 0;
0107         break;
0108     case OTG_STATE_A_WAIT_VFALL:
0109         otg_del_timer(fsm, A_WAIT_VFALL);
0110         fsm->a_wait_vfall_tmout = 0;
0111         otg_del_timer(fsm, A_WAIT_VRISE);
0112         break;
0113     case OTG_STATE_A_VBUS_ERR:
0114         break;
0115     default:
0116         break;
0117     }
0118 }
0119
0120 static void otg_hnp_polling_work(struct work_struct *work)
0121 {
0122     struct otg_fsm *fsm = container_of(to_delayed_work(work),
0123                 struct otg_fsm, hnp_polling_work);
0124     struct usb_device *udev;
0125     enum usb_otg_state state = fsm->otg->state;
0126     u8 flag;
0127     int retval;
0128
0129     if (state != OTG_STATE_A_HOST && state != OTG_STATE_B_HOST)
0130         return;
0131
0132     udev = usb_hub_find_child(fsm->otg->host->root_hub, 1);
0133     if (!udev) {
0134         dev_err(fsm->otg->host->controller,
0135             "no usb dev connected, can't start HNP polling\n");
0136         return;
0137     }
0138
0139     *fsm->host_req_flag = 0;
0140     /* Get host request flag from connected USB device */
0141     retval = usb_control_msg(udev,
0142                 usb_rcvctrlpipe(udev, 0),
0143                 USB_REQ_GET_STATUS,
0144                 USB_DIR_IN | USB_RECIP_DEVICE,
0145                 0,
0146                 OTG_STS_SELECTOR,
0147                 fsm->host_req_flag,
0148                 1,
0149                 USB_CTRL_GET_TIMEOUT);
0150     if (retval != 1) {
0151         dev_err(&udev->dev, "Get one byte OTG status failed\n");
0152         return;
0153     }
0154
0155     flag = *fsm->host_req_flag;
0156     if (flag == 0) {
0157         /* Continue HNP polling */
0158         schedule_delayed_work(&fsm->hnp_polling_work,
0159                     msecs_to_jiffies(T_HOST_REQ_POLL));
0160         return;
0161     } else if (flag != HOST_REQUEST_FLAG) {
0162         dev_err(&udev->dev, "host request flag %d is invalid\n", flag);
0163         return;
0164     }
0165
0166     /* Host request flag is set */
0167     if (state == OTG_STATE_A_HOST) {
0168         /* Set b_hnp_enable */
0169         if (!fsm->otg->host->b_hnp_enable) {
0170             retval = usb_control_msg(udev,
0171                     usb_sndctrlpipe(udev, 0),
0172                     USB_REQ_SET_FEATURE, 0,
0173                     USB_DEVICE_B_HNP_ENABLE,
0174                     0, NULL, 0,
0175                     USB_CTRL_SET_TIMEOUT);
0176             if (retval >= 0)
0177                 fsm->otg->host->b_hnp_enable = 1;
0178         }
0179         fsm->a_bus_req = 0;
0180     } else if (state == OTG_STATE_B_HOST) {
0181         fsm->b_bus_req = 0;
0182     }
0183
0184     otg_statemachine(fsm);
0185 }
0186
0187 static void otg_start_hnp_polling(struct otg_fsm *fsm)
0188 {
0189     /*
0190      * The memory of host_req_flag should be allocated by
0191      * controller driver, otherwise, hnp polling is not started.
0192      */
0193     if (!fsm->host_req_flag)
0194         return;
0195
0196     if (!fsm->hnp_work_inited) {
0197         INIT_DELAYED_WORK(&fsm->hnp_polling_work, otg_hnp_polling_work);
0198         fsm->hnp_work_inited = true;
0199     }
0200
0201     schedule_delayed_work(&fsm->hnp_polling_work,
0202                     msecs_to_jiffies(T_HOST_REQ_POLL));
0203 }
0204
0205 /* Called when entering a state */
0206 static int otg_set_state(struct otg_fsm *fsm, enum usb_otg_state new_state)
0207 {
0208     if (fsm->otg->state == new_state)
0209         return 0;
0210     VDBG("Set state: %s\n", usb_otg_state_string(new_state));
0211     otg_leave_state(fsm, fsm->otg->state);
0212     switch (new_state) {
0213     case OTG_STATE_B_IDLE:
0214         otg_drv_vbus(fsm, 0);
0215         otg_chrg_vbus(fsm, 0);
0216         otg_loc_conn(fsm, 0);
0217         otg_loc_sof(fsm, 0);
0218         /*
0219          * Driver is responsible for starting ADP probing
0220          * if ADP sensing times out.
0221          */
0222         otg_start_adp_sns(fsm);
0223         otg_set_protocol(fsm, PROTO_UNDEF);
0224         otg_add_timer(fsm, B_SE0_SRP);
0225         break;
0226     case OTG_STATE_B_SRP_INIT:
0227         otg_start_pulse(fsm);
0228         otg_loc_sof(fsm, 0);
0229         otg_set_protocol(fsm, PROTO_UNDEF);
0230         otg_add_timer(fsm, B_SRP_FAIL);
0231         break;
0232     case OTG_STATE_B_PERIPHERAL:
0233         otg_chrg_vbus(fsm, 0);
0234         otg_loc_sof(fsm, 0);
0235         otg_set_protocol(fsm, PROTO_GADGET);
0236         otg_loc_conn(fsm, 1);
0237         break;
0238     case OTG_STATE_B_WAIT_ACON:
0239         otg_chrg_vbus(fsm, 0);
0240         otg_loc_conn(fsm, 0);
0241         otg_loc_sof(fsm, 0);
0242         otg_set_protocol(fsm, PROTO_HOST);
0243         otg_add_timer(fsm, B_ASE0_BRST);
0244         fsm->a_bus_suspend = 0;
0245         break;
0246     case OTG_STATE_B_HOST:
0247         otg_chrg_vbus(fsm, 0);
0248         otg_loc_conn(fsm, 0);
0249         otg_loc_sof(fsm, 1);
0250         otg_set_protocol(fsm, PROTO_HOST);
0251         usb_bus_start_enum(fsm->otg->host,
0252                 fsm->otg->host->otg_port);
0253         otg_start_hnp_polling(fsm);
0254         break;
0255     case OTG_STATE_A_IDLE:
0256         otg_drv_vbus(fsm, 0);
0257         otg_chrg_vbus(fsm, 0);
0258         otg_loc_conn(fsm, 0);
0259         otg_loc_sof(fsm, 0);
0260         otg_start_adp_prb(fsm);
0261         otg_set_protocol(fsm, PROTO_HOST);
0262         break;
0263     case OTG_STATE_A_WAIT_VRISE:
0264         otg_drv_vbus(fsm, 1);
0265         otg_loc_conn(fsm, 0);
0266         otg_loc_sof(fsm, 0);
0267         otg_set_protocol(fsm, PROTO_HOST);
0268         otg_add_timer(fsm, A_WAIT_VRISE);
0269         break;
0270     case OTG_STATE_A_WAIT_BCON:
0271         otg_drv_vbus(fsm, 1);
0272         otg_loc_conn(fsm, 0);
0273         otg_loc_sof(fsm, 0);
0274         otg_set_protocol(fsm, PROTO_HOST);
0275         otg_add_timer(fsm, A_WAIT_BCON);
0276         break;
0277     case OTG_STATE_A_HOST:
0278         otg_drv_vbus(fsm, 1);
0279         otg_loc_conn(fsm, 0);
0280         otg_loc_sof(fsm, 1);
0281         otg_set_protocol(fsm, PROTO_HOST);
0282         /*
0283          * When HNP is triggered while a_bus_req = 0, a_host will
0284          * suspend too fast to complete a_set_b_hnp_en
0285          */
0286         if (!fsm->a_bus_req || fsm->a_suspend_req_inf)
0287             otg_add_timer(fsm, A_WAIT_ENUM);
0288         otg_start_hnp_polling(fsm);
0289         break;
0290     case OTG_STATE_A_SUSPEND:
0291         otg_drv_vbus(fsm, 1);
0292         otg_loc_conn(fsm, 0);
0293         otg_loc_sof(fsm, 0);
0294         otg_set_protocol(fsm, PROTO_HOST);
0295         otg_add_timer(fsm, A_AIDL_BDIS);
0296
0297         break;
0298     case OTG_STATE_A_PERIPHERAL:
0299         otg_loc_sof(fsm, 0);
0300         otg_set_protocol(fsm, PROTO_GADGET);
0301         otg_drv_vbus(fsm, 1);
0302         otg_loc_conn(fsm, 1);
0303         otg_add_timer(fsm, A_BIDL_ADIS);
0304         break;
0305     case OTG_STATE_A_WAIT_VFALL:
0306         otg_drv_vbus(fsm, 0);
0307         otg_loc_conn(fsm, 0);
0308         otg_loc_sof(fsm, 0);
0309         otg_set_protocol(fsm, PROTO_HOST);
0310         otg_add_timer(fsm, A_WAIT_VFALL);
0311         break;
0312     case OTG_STATE_A_VBUS_ERR:
0313         otg_drv_vbus(fsm, 0);
0314         otg_loc_conn(fsm, 0);
0315         otg_loc_sof(fsm, 0);
0316         otg_set_protocol(fsm, PROTO_UNDEF);
0317         break;
0318     default:
0319         break;
0320     }
0321
0322     fsm->otg->state = new_state;
0323     fsm->state_changed = 1;
0324     return 0;
0325 }
0326
0327 /* State change judgement */
0328 int otg_statemachine(struct otg_fsm *fsm)
0329 {
0330     enum usb_otg_state state;
0331
0332     mutex_lock(&fsm->lock);
0333
0334     state = fsm->otg->state;
0335     fsm->state_changed = 0;
0336     /* State machine state change judgement */
0337
0338     switch (state) {
0339     case OTG_STATE_UNDEFINED:
0340         VDBG("fsm->id = %d\n", fsm->id);
0341         if (fsm->id)
0342             otg_set_state(fsm, OTG_STATE_B_IDLE);
0343         else
0344             otg_set_state(fsm, OTG_STATE_A_IDLE);
0345         break;
0346     case OTG_STATE_B_IDLE:
0347         if (!fsm->id)
0348             otg_set_state(fsm, OTG_STATE_A_IDLE);
0349         else if (fsm->b_sess_vld && fsm->otg->gadget)
0350             otg_set_state(fsm, OTG_STATE_B_PERIPHERAL);
0351         else if ((fsm->b_bus_req || fsm->adp_change || fsm->power_up) &&
0352                 fsm->b_ssend_srp && fsm->b_se0_srp)
0353             otg_set_state(fsm, OTG_STATE_B_SRP_INIT);
0354         break;
0355     case OTG_STATE_B_SRP_INIT:
0356         if (!fsm->id || fsm->b_srp_done)
0357             otg_set_state(fsm, OTG_STATE_B_IDLE);
0358         break;
0359     case OTG_STATE_B_PERIPHERAL:
0360         if (!fsm->id || !fsm->b_sess_vld)
0361             otg_set_state(fsm, OTG_STATE_B_IDLE);
0362         else if (fsm->b_bus_req && fsm->otg->
0363                 gadget->b_hnp_enable && fsm->a_bus_suspend)
0364             otg_set_state(fsm, OTG_STATE_B_WAIT_ACON);
0365         break;
0366     case OTG_STATE_B_WAIT_ACON:
0367         if (fsm->a_conn)
0368             otg_set_state(fsm, OTG_STATE_B_HOST);
0369         else if (!fsm->id || !fsm->b_sess_vld)
0370             otg_set_state(fsm, OTG_STATE_B_IDLE);
0371         else if (fsm->a_bus_resume || fsm->b_ase0_brst_tmout) {
0372             fsm->b_ase0_brst_tmout = 0;
0373             otg_set_state(fsm, OTG_STATE_B_PERIPHERAL);
0374         }
0375         break;
0376     case OTG_STATE_B_HOST:
0377         if (!fsm->id || !fsm->b_sess_vld)
0378             otg_set_state(fsm, OTG_STATE_B_IDLE);
0379         else if (!fsm->b_bus_req || !fsm->a_conn || fsm->test_device)
0380             otg_set_state(fsm, OTG_STATE_B_PERIPHERAL);
0381         break;
0382     case OTG_STATE_A_IDLE:
0383         if (fsm->id)
0384             otg_set_state(fsm, OTG_STATE_B_IDLE);
0385         else if (!fsm->a_bus_drop && (fsm->a_bus_req ||
0386               fsm->a_srp_det || fsm->adp_change || fsm->power_up))
0387             otg_set_state(fsm, OTG_STATE_A_WAIT_VRISE);
0388         break;
0389     case OTG_STATE_A_WAIT_VRISE:
0390         if (fsm->a_vbus_vld)
0391             otg_set_state(fsm, OTG_STATE_A_WAIT_BCON);
0392         else if (fsm->id || fsm->a_bus_drop ||
0393                 fsm->a_wait_vrise_tmout)
0394             otg_set_state(fsm, OTG_STATE_A_WAIT_VFALL);
0395         break;
0396     case OTG_STATE_A_WAIT_BCON:
0397         if (!fsm->a_vbus_vld)
0398             otg_set_state(fsm, OTG_STATE_A_VBUS_ERR);
0399         else if (fsm->b_conn)
0400             otg_set_state(fsm, OTG_STATE_A_HOST);
0401         else if (fsm->id || fsm->a_bus_drop || fsm->a_wait_bcon_tmout)
0402             otg_set_state(fsm, OTG_STATE_A_WAIT_VFALL);
0403         break;
0404     case OTG_STATE_A_HOST:
0405         if (fsm->id || fsm->a_bus_drop)
0406             otg_set_state(fsm, OTG_STATE_A_WAIT_VFALL);
0407         else if ((!fsm->a_bus_req || fsm->a_suspend_req_inf) &&
0408                 fsm->otg->host->b_hnp_enable)
0409             otg_set_state(fsm, OTG_STATE_A_SUSPEND);
0410         else if (!fsm->b_conn)
0411             otg_set_state(fsm, OTG_STATE_A_WAIT_BCON);
0412         else if (!fsm->a_vbus_vld)
0413             otg_set_state(fsm, OTG_STATE_A_VBUS_ERR);
0414         break;
0415     case OTG_STATE_A_SUSPEND:
0416         if (!fsm->b_conn && fsm->otg->host->b_hnp_enable)
0417             otg_set_state(fsm, OTG_STATE_A_PERIPHERAL);
0418         else if (!fsm->b_conn && !fsm->otg->host->b_hnp_enable)
0419             otg_set_state(fsm, OTG_STATE_A_WAIT_BCON);
0420         else if (fsm->a_bus_req || fsm->b_bus_resume)
0421             otg_set_state(fsm, OTG_STATE_A_HOST);
0422         else if (fsm->id || fsm->a_bus_drop || fsm->a_aidl_bdis_tmout)
0423             otg_set_state(fsm, OTG_STATE_A_WAIT_VFALL);
0424         else if (!fsm->a_vbus_vld)
0425             otg_set_state(fsm, OTG_STATE_A_VBUS_ERR);
0426         break;
0427     case OTG_STATE_A_PERIPHERAL:
0428         if (fsm->id || fsm->a_bus_drop)
0429             otg_set_state(fsm, OTG_STATE_A_WAIT_VFALL);
0430         else if (fsm->a_bidl_adis_tmout || fsm->b_bus_suspend)
0431             otg_set_state(fsm, OTG_STATE_A_WAIT_BCON);
0432         else if (!fsm->a_vbus_vld)
0433             otg_set_state(fsm, OTG_STATE_A_VBUS_ERR);
0434         break;
0435     case OTG_STATE_A_WAIT_VFALL:
0436         if (fsm->a_wait_vfall_tmout)
0437             otg_set_state(fsm, OTG_STATE_A_IDLE);
0438         break;
0439     case OTG_STATE_A_VBUS_ERR:
0440         if (fsm->id || fsm->a_bus_drop || fsm->a_clr_err)
0441             otg_set_state(fsm, OTG_STATE_A_WAIT_VFALL);
0442         break;
0443     default:
0444         break;
0445     }
0446     mutex_unlock(&fsm->lock);
0447
0448     VDBG("quit statemachine, changed = %d\n", fsm->state_changed);
0449     return fsm->state_changed;
0450 }
0451 EXPORT_SYMBOL_GPL(otg_statemachine);
0452 MODULE_LICENSE("GPL");