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         struct timespec64 ts = {
  67                 .tv_sec = msg->timespec.tv_sec,
  68                 .tv_nsec = msg->timespec.tv_nsec,
  69         };
  70         int rc = do_settimeofday64(&ts);
  71
  72         if (rc)
  73                 dev_err(&client_spdev->dev, "%s: %d settimeofday rc %d\n",
  74                         __func__, __LINE__, rc);
  75 }
  76
  77 /* COSM client receive message processing */
  78 static void cosm_client_recv(void)
  79 {
  80         struct cosm_msg msg;
  81         int rc;
  82
  83         while (1) {
  84                 rc = scif_recv(client_epd, &msg, sizeof(msg), 0);
  85                 if (!rc) {
  86                         return;
  87                 } else if (rc < 0) {
  88                         dev_err(&client_spdev->dev, "%s: %d rc %d\n",
  89                                 __func__, __LINE__, rc);
  90                         return;
  91                 }
  92
  93                 dev_dbg(&client_spdev->dev, "%s: %d rc %d id 0x%llx\n",
  94                         __func__, __LINE__, rc, msg.id);
  95
  96                 switch (msg.id) {
  97                 case COSM_MSG_SYNC_TIME:
  98                         cosm_set_time(&msg);
  99                         break;
 100                 case COSM_MSG_SHUTDOWN:
 101                         orderly_poweroff(true);
 102                         break;
 103                 default:
 104                         dev_err(&client_spdev->dev, "%s: %d unknown id %lld\n",
 105                                 __func__, __LINE__, msg.id);
 106                         break;
 107                 }
 108         }
 109 }
 110
 111 /* Initiate connection to the COSM server on the host */
 112 static int cosm_scif_connect(void)
 113 {
 114         struct scif_port_id port_id;
 115         int i, rc;
 116
 117         client_epd = scif_open();
 118         if (!client_epd) {
 119                 dev_err(&client_spdev->dev, "%s %d scif_open failed\n",
 120                         __func__, __LINE__);
 121                 return -ENOMEM;
 122         }
 123
 124         port_id.node = 0;
 125         port_id.port = SCIF_COSM_LISTEN_PORT;
 126
 127         for (i = 0; i < COSM_SCIF_MAX_RETRIES; i++) {
 128                 rc = scif_connect(client_epd, &port_id);
 129                 if (rc < 0)
 130                         msleep(1000);
 131                 else
 132                         break;
 133         }
 134
 135         if (rc < 0) {
 136                 dev_err(&client_spdev->dev, "%s %d scif_connect rc %d\n",
 137                         __func__, __LINE__, rc);
 138                 scif_close(client_epd);
 139                 client_epd = NULL;
 140         }
 141         return rc < 0 ? rc : 0;
 142 }
 143
 144 /* Close host SCIF connection */
 145 static void cosm_scif_connect_exit(void)
 146 {
 147         if (client_epd) {
 148                 scif_close(client_epd);
 149                 client_epd = NULL;
 150         }
 151 }
 152
 153 /*
 154  * COSM SCIF client thread function: waits for messages from the host and sends
 155  * a heartbeat to the host
 156  */
 157 static int cosm_scif_client(void *unused)
 158 {
 159         struct cosm_msg msg = { .id = COSM_MSG_HEARTBEAT };
 160         struct scif_pollepd pollepd;
 161         int rc;
 162
 163         allow_signal(SIGKILL);
 164
 165         while (!kthread_should_stop()) {
 166                 pollepd.epd = client_epd;
 167                 pollepd.events = EPOLLIN;
 168
 169                 rc = scif_poll(&pollepd, 1, COSM_HEARTBEAT_SEND_MSEC);
 170                 if (rc < 0) {
 171                         if (-EINTR != rc)
 172                                 dev_err(&client_spdev->dev,
 173                                         "%s %d scif_poll rc %d\n",
 174                                         __func__, __LINE__, rc);
 175                         continue;
 176                 }
 177
 178                 if (pollepd.revents & EPOLLIN)
 179                         cosm_client_recv();
 180
 181                 msg.id = COSM_MSG_HEARTBEAT;
 182                 rc = scif_send(client_epd, &msg, sizeof(msg), SCIF_SEND_BLOCK);
 183                 if (rc < 0)
 184                         dev_err(&client_spdev->dev, "%s %d scif_send rc %d\n",
 185                                 __func__, __LINE__, rc);
 186         }
 187
 188         dev_dbg(&client_spdev->dev, "%s %d Client thread stopped\n",
 189                 __func__, __LINE__);
 190         return 0;
 191 }
 192
 193 static void cosm_scif_probe(struct scif_peer_dev *spdev)
 194 {
 195         int rc;
 196
 197         dev_dbg(&spdev->dev, "%s %d: dnode %d\n",
 198                 __func__, __LINE__, spdev->dnode);
 199
 200         /* We are only interested in the host with spdev->dnode == 0 */
 201         if (spdev->dnode)
 202                 return;
 203
 204         client_spdev = spdev;
 205         rc = cosm_scif_connect();
 206         if (rc)
 207                 goto exit;
 208
 209         rc = register_reboot_notifier(&cosm_reboot);
 210         if (rc) {
 211                 dev_err(&spdev->dev,
 212                         "reboot notifier registration failed rc %d\n", rc);
 213                 goto connect_exit;
 214         }
 215
 216         client_thread = kthread_run(cosm_scif_client, NULL, "cosm_client");
 217         if (IS_ERR(client_thread)) {
 218                 rc = PTR_ERR(client_thread);
 219                 dev_err(&spdev->dev, "%s %d kthread_run rc %d\n",
 220                         __func__, __LINE__, rc);
 221                 goto unreg_reboot;
 222         }
 223         return;
 224 unreg_reboot:
 225         unregister_reboot_notifier(&cosm_reboot);
 226 connect_exit:
 227         cosm_scif_connect_exit();
 228 exit:
 229         client_spdev = NULL;
 230 }
 231
 232 static void cosm_scif_remove(struct scif_peer_dev *spdev)
 233 {
 234         int rc;
 235
 236         dev_dbg(&spdev->dev, "%s %d: dnode %d\n",
 237                 __func__, __LINE__, spdev->dnode);
 238
 239         if (spdev->dnode)
 240                 return;
 241
 242         if (!IS_ERR_OR_NULL(client_thread)) {
 243                 rc = send_sig(SIGKILL, client_thread, 0);
 244                 if (rc) {
 245                         pr_err("%s %d send_sig rc %d\n",
 246                                __func__, __LINE__, rc);
 247                         return;
 248                 }
 249                 kthread_stop(client_thread);
 250         }
 251         unregister_reboot_notifier(&cosm_reboot);
 252         cosm_scif_connect_exit();
 253         client_spdev = NULL;
 254 }
 255
 256 static struct scif_client scif_client_cosm = {
 257         .name = KBUILD_MODNAME,
 258         .probe = cosm_scif_probe,
 259         .remove = cosm_scif_remove,
 260 };
 261
 262 static int __init cosm_client_init(void)
 263 {
 264         int rc = scif_client_register(&scif_client_cosm);
 265
 266         if (rc)
 267                 pr_err("scif_client_register failed rc %d\n", rc);
 268         return rc;
 269 }
 270
 271 static void __exit cosm_client_exit(void)
 272 {
 273         scif_client_unregister(&scif_client_cosm);
 274 }
 275
 276 module_init(cosm_client_init);
 277 module_exit(cosm_client_exit);
 278
 279 MODULE_AUTHOR("Intel Corporation");
 280 MODULE_DESCRIPTION("Intel(R) MIC card OS state management client driver");
 281 MODULE_LICENSE("GPL v2");