drivers/misc/mic/cosm_client/cosm_scif_client.c

   1 /*
   2  * Intel MIC Platform Software Stack (MPSS)
   3  *
   4  * Copyright(c) 2015 Intel Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 2, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * The full GNU General Public License is included in this distribution in
  16  * the file called "COPYING".
  17  *
  18  * Intel MIC COSM Client Driver
  19  *
  20  */
  21 #include <linux/module.h>
  22 #include <linux/delay.h>
  23 #include <linux/reboot.h>
  24 #include <linux/kthread.h>
  25 #include <linux/sched/signal.h>
  26
  27 #include "../cosm/cosm_main.h"
  28
  29 #define COSM_SCIF_MAX_RETRIES 10
  30 #define COSM_HEARTBEAT_SEND_MSEC (COSM_HEARTBEAT_SEND_SEC * MSEC_PER_SEC)
  31
  32 static struct task_struct *client_thread;
  33 static scif_epd_t client_epd;
  34 static struct scif_peer_dev *client_spdev;
  35
  36 /*
  37  * Reboot notifier: receives shutdown status from the OS and communicates it
  38  * back to the COSM process on the host
  39  */
  40 static int cosm_reboot_event(struct notifier_block *this, unsigned long event,
  41                              void *ptr)
  42 {
  43         struct cosm_msg msg = { .id = COSM_MSG_SHUTDOWN_STATUS };
  44         int rc;
  45
  46         event = (event == SYS_RESTART) ? SYSTEM_RESTART : event;
  47         dev_info(&client_spdev->dev, "%s %d received event %ld\n",
  48                  __func__, __LINE__, event);
  49
  50         msg.shutdown_status = event;
  51         rc = scif_send(client_epd, &msg, sizeof(msg), SCIF_SEND_BLOCK);
  52         if (rc < 0)
  53                 dev_err(&client_spdev->dev, "%s %d scif_send rc %d\n",
  54                         __func__, __LINE__, rc);
  55
  56         return NOTIFY_DONE;
  57 }
  58
  59 static struct notifier_block cosm_reboot = {
  60         .notifier_call  = cosm_reboot_event,
  61 };
  62
  63 /* Set system time from timespec value received from the host */
  64 static void cosm_set_time(struct cosm_msg *msg)
  65 {
  66         int rc = do_settimeofday64(&msg->timespec);
  67
  68         if (rc)
  69                 dev_err(&client_spdev->dev, "%s: %d settimeofday rc %d\n",
  70                         __func__, __LINE__, rc);
  71 }
  72
  73 /* COSM client receive message processing */
  74 static void cosm_client_recv(void)
  75 {
  76         struct cosm_msg msg;
  77         int rc;
  78
  79         while (1) {
  80                 rc = scif_recv(client_epd, &msg, sizeof(msg), 0);
  81                 if (!rc) {
  82                         return;
  83                 } else if (rc < 0) {
  84                         dev_err(&client_spdev->dev, "%s: %d rc %d\n",
  85                                 __func__, __LINE__, rc);
  86                         return;
  87                 }
  88
  89                 dev_dbg(&client_spdev->dev, "%s: %d rc %d id 0x%llx\n",
  90                         __func__, __LINE__, rc, msg.id);
  91
  92                 switch (msg.id) {
  93                 case COSM_MSG_SYNC_TIME:
  94                         cosm_set_time(&msg);
  95                         break;
  96                 case COSM_MSG_SHUTDOWN:
  97                         orderly_poweroff(true);
  98                         break;
  99                 default:
 100                         dev_err(&client_spdev->dev, "%s: %d unknown id %lld\n",
 101                                 __func__, __LINE__, msg.id);
 102                         break;
 103                 }
 104         }
 105 }
 106
 107 /* Initiate connection to the COSM server on the host */
 108 static int cosm_scif_connect(void)
 109 {
 110         struct scif_port_id port_id;
 111         int i, rc;
 112
 113         client_epd = scif_open();
 114         if (!client_epd) {
 115                 dev_err(&client_spdev->dev, "%s %d scif_open failed\n",
 116                         __func__, __LINE__);
 117                 return -ENOMEM;
 118         }
 119
 120         port_id.node = 0;
 121         port_id.port = SCIF_COSM_LISTEN_PORT;
 122
 123         for (i = 0; i < COSM_SCIF_MAX_RETRIES; i++) {
 124                 rc = scif_connect(client_epd, &port_id);
 125                 if (rc < 0)
 126                         msleep(1000);
 127                 else
 128                         break;
 129         }
 130
 131         if (rc < 0) {
 132                 dev_err(&client_spdev->dev, "%s %d scif_connect rc %d\n",
 133                         __func__, __LINE__, rc);
 134                 scif_close(client_epd);
 135                 client_epd = NULL;
 136         }
 137         return rc < 0 ? rc : 0;
 138 }
 139
 140 /* Close host SCIF connection */
 141 static void cosm_scif_connect_exit(void)
 142 {
 143         if (client_epd) {
 144                 scif_close(client_epd);
 145                 client_epd = NULL;
 146         }
 147 }
 148
 149 /*
 150  * COSM SCIF client thread function: waits for messages from the host and sends
 151  * a heartbeat to the host
 152  */
 153 static int cosm_scif_client(void *unused)
 154 {
 155         struct cosm_msg msg = { .id = COSM_MSG_HEARTBEAT };
 156         struct scif_pollepd pollepd;
 157         int rc;
 158
 159         allow_signal(SIGKILL);
 160
 161         while (!kthread_should_stop()) {
 162                 pollepd.epd = client_epd;
 163                 pollepd.events = EPOLLIN;
 164
 165                 rc = scif_poll(&pollepd, 1, COSM_HEARTBEAT_SEND_MSEC);
 166                 if (rc < 0) {
 167                         if (-EINTR != rc)
 168                                 dev_err(&client_spdev->dev,
 169                                         "%s %d scif_poll rc %d\n",
 170                                         __func__, __LINE__, rc);
 171                         continue;
 172                 }
 173
 174                 if (pollepd.revents & EPOLLIN)
 175                         cosm_client_recv();
 176
 177                 msg.id = COSM_MSG_HEARTBEAT;
 178                 rc = scif_send(client_epd, &msg, sizeof(msg), SCIF_SEND_BLOCK);
 179                 if (rc < 0)
 180                         dev_err(&client_spdev->dev, "%s %d scif_send rc %d\n",
 181                                 __func__, __LINE__, rc);
 182         }
 183
 184         dev_dbg(&client_spdev->dev, "%s %d Client thread stopped\n",
 185                 __func__, __LINE__);
 186         return 0;
 187 }
 188
 189 static void cosm_scif_probe(struct scif_peer_dev *spdev)
 190 {
 191         int rc;
 192
 193         dev_dbg(&spdev->dev, "%s %d: dnode %d\n",
 194                 __func__, __LINE__, spdev->dnode);
 195
 196         /* We are only interested in the host with spdev->dnode == 0 */
 197         if (spdev->dnode)
 198                 return;
 199
 200         client_spdev = spdev;
 201         rc = cosm_scif_connect();
 202         if (rc)
 203                 goto exit;
 204
 205         rc = register_reboot_notifier(&cosm_reboot);
 206         if (rc) {
 207                 dev_err(&spdev->dev,
 208                         "reboot notifier registration failed rc %d\n", rc);
 209                 goto connect_exit;
 210         }
 211
 212         client_thread = kthread_run(cosm_scif_client, NULL, "cosm_client");
 213         if (IS_ERR(client_thread)) {
 214                 rc = PTR_ERR(client_thread);
 215                 dev_err(&spdev->dev, "%s %d kthread_run rc %d\n",
 216                         __func__, __LINE__, rc);
 217                 goto unreg_reboot;
 218         }
 219         return;
 220 unreg_reboot:
 221         unregister_reboot_notifier(&cosm_reboot);
 222 connect_exit:
 223         cosm_scif_connect_exit();
 224 exit:
 225         client_spdev = NULL;
 226 }
 227
 228 static void cosm_scif_remove(struct scif_peer_dev *spdev)
 229 {
 230         int rc;
 231
 232         dev_dbg(&spdev->dev, "%s %d: dnode %d\n",
 233                 __func__, __LINE__, spdev->dnode);
 234
 235         if (spdev->dnode)
 236                 return;
 237
 238         if (!IS_ERR_OR_NULL(client_thread)) {
 239                 rc = send_sig(SIGKILL, client_thread, 0);
 240                 if (rc) {
 241                         pr_err("%s %d send_sig rc %d\n",
 242                                __func__, __LINE__, rc);
 243                         return;
 244                 }
 245                 kthread_stop(client_thread);
 246         }
 247         unregister_reboot_notifier(&cosm_reboot);
 248         cosm_scif_connect_exit();
 249         client_spdev = NULL;
 250 }
 251
 252 static struct scif_client scif_client_cosm = {
 253         .name = KBUILD_MODNAME,
 254         .probe = cosm_scif_probe,
 255         .remove = cosm_scif_remove,
 256 };
 257
 258 static int __init cosm_client_init(void)
 259 {
 260         int rc = scif_client_register(&scif_client_cosm);
 261
 262         if (rc)
 263                 pr_err("scif_client_register failed rc %d\n", rc);
 264         return rc;
 265 }
 266
 267 static void __exit cosm_client_exit(void)
 268 {
 269         scif_client_unregister(&scif_client_cosm);
 270 }
 271
 272 module_init(cosm_client_init);
 273 module_exit(cosm_client_exit);
 274
 275 MODULE_AUTHOR("Intel Corporation");
 276 MODULE_DESCRIPTION("Intel(R) MIC card OS state management client driver");
 277 MODULE_LICENSE("GPL v2");