1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Intel MIC Platform Software Stack (MPSS)
  4 *
  5 * Copyright(c) 2015 Intel Corporation.
  6 *
  7 * Intel MIC COSM Client Driver
  8 */
  9#include <linux/module.h>
 10#include <linux/delay.h>
 11#include <linux/reboot.h>
 12#include <linux/kthread.h>
 13#include <linux/sched/signal.h>
 14
 15#include "../cosm/cosm_main.h"
 16
 17#define COSM_SCIF_MAX_RETRIES 10
 18#define COSM_HEARTBEAT_SEND_MSEC (COSM_HEARTBEAT_SEND_SEC * MSEC_PER_SEC)
 19
 20static struct task_struct *client_thread;
 21static scif_epd_t client_epd;
 22static struct scif_peer_dev *client_spdev;
 23
 24/*
 25 * Reboot notifier: receives shutdown status from the OS and communicates it
 26 * back to the COSM process on the host
 27 */
 28static int cosm_reboot_event(struct notifier_block *this, unsigned long event,
 29			     void *ptr)
 30{
 31	struct cosm_msg msg = { .id = COSM_MSG_SHUTDOWN_STATUS };
 32	int rc;
 33
 34	event = (event == SYS_RESTART) ? SYSTEM_RESTART : event;
 35	dev_info(&client_spdev->dev, "%s %d received event %ld\n",
 36		 __func__, __LINE__, event);
 37
 38	msg.shutdown_status = event;
 39	rc = scif_send(client_epd, &msg, sizeof(msg), SCIF_SEND_BLOCK);
 40	if (rc < 0)
 41		dev_err(&client_spdev->dev, "%s %d scif_send rc %d\n",
 42			__func__, __LINE__, rc);
 43
 44	return NOTIFY_DONE;
 45}
 46
 47static struct notifier_block cosm_reboot = {
 48	.notifier_call  = cosm_reboot_event,
 49};
 50
 51/* Set system time from timespec value received from the host */
 52static void cosm_set_time(struct cosm_msg *msg)
 53{
 54	struct timespec64 ts = {
 55		.tv_sec = msg->timespec.tv_sec,
 56		.tv_nsec = msg->timespec.tv_nsec,
 57	};
 58	int rc = do_settimeofday64(&ts);
 59
 60	if (rc)
 61		dev_err(&client_spdev->dev, "%s: %d settimeofday rc %d\n",
 62			__func__, __LINE__, rc);
 63}
 64
 65/* COSM client receive message processing */
 66static void cosm_client_recv(void)
 67{
 68	struct cosm_msg msg;
 69	int rc;
 70
 71	while (1) {
 72		rc = scif_recv(client_epd, &msg, sizeof(msg), 0);
 73		if (!rc) {
 74			return;
 75		} else if (rc < 0) {
 76			dev_err(&client_spdev->dev, "%s: %d rc %d\n",
 77				__func__, __LINE__, rc);
 78			return;
 79		}
 80
 81		dev_dbg(&client_spdev->dev, "%s: %d rc %d id 0x%llx\n",
 82			__func__, __LINE__, rc, msg.id);
 83
 84		switch (msg.id) {
 85		case COSM_MSG_SYNC_TIME:
 86			cosm_set_time(&msg);
 87			break;
 88		case COSM_MSG_SHUTDOWN:
 89			orderly_poweroff(true);
 90			break;
 91		default:
 92			dev_err(&client_spdev->dev, "%s: %d unknown id %lld\n",
 93				__func__, __LINE__, msg.id);
 94			break;
 95		}
 96	}
 97}
 98
 99/* Initiate connection to the COSM server on the host */
100static int cosm_scif_connect(void)
101{
102	struct scif_port_id port_id;
103	int i, rc;
104
105	client_epd = scif_open();
106	if (!client_epd) {
107		dev_err(&client_spdev->dev, "%s %d scif_open failed\n",
108			__func__, __LINE__);
109		return -ENOMEM;
110	}
111
112	port_id.node = 0;
113	port_id.port = SCIF_COSM_LISTEN_PORT;
114
115	for (i = 0; i < COSM_SCIF_MAX_RETRIES; i++) {
116		rc = scif_connect(client_epd, &port_id);
117		if (rc < 0)
118			msleep(1000);
119		else
120			break;
121	}
122
123	if (rc < 0) {
124		dev_err(&client_spdev->dev, "%s %d scif_connect rc %d\n",
125			__func__, __LINE__, rc);
126		scif_close(client_epd);
127		client_epd = NULL;
128	}
129	return rc < 0 ? rc : 0;
130}
131
132/* Close host SCIF connection */
133static void cosm_scif_connect_exit(void)
134{
135	if (client_epd) {
136		scif_close(client_epd);
137		client_epd = NULL;
138	}
139}
140
141/*
142 * COSM SCIF client thread function: waits for messages from the host and sends
143 * a heartbeat to the host
144 */
145static int cosm_scif_client(void *unused)
146{
147	struct cosm_msg msg = { .id = COSM_MSG_HEARTBEAT };
148	struct scif_pollepd pollepd;
149	int rc;
150
151	allow_signal(SIGKILL);
152
153	while (!kthread_should_stop()) {
154		pollepd.epd = client_epd;
155		pollepd.events = EPOLLIN;
156
157		rc = scif_poll(&pollepd, 1, COSM_HEARTBEAT_SEND_MSEC);
158		if (rc < 0) {
159			if (-EINTR != rc)
160				dev_err(&client_spdev->dev,
161					"%s %d scif_poll rc %d\n",
162					__func__, __LINE__, rc);
163			continue;
164		}
165
166		if (pollepd.revents & EPOLLIN)
167			cosm_client_recv();
168
169		msg.id = COSM_MSG_HEARTBEAT;
170		rc = scif_send(client_epd, &msg, sizeof(msg), SCIF_SEND_BLOCK);
171		if (rc < 0)
172			dev_err(&client_spdev->dev, "%s %d scif_send rc %d\n",
173				__func__, __LINE__, rc);
174	}
175
176	dev_dbg(&client_spdev->dev, "%s %d Client thread stopped\n",
177		__func__, __LINE__);
178	return 0;
179}
180
181static void cosm_scif_probe(struct scif_peer_dev *spdev)
182{
183	int rc;
184
185	dev_dbg(&spdev->dev, "%s %d: dnode %d\n",
186		__func__, __LINE__, spdev->dnode);
187
188	/* We are only interested in the host with spdev->dnode == 0 */
189	if (spdev->dnode)
190		return;
191
192	client_spdev = spdev;
193	rc = cosm_scif_connect();
194	if (rc)
195		goto exit;
196
197	rc = register_reboot_notifier(&cosm_reboot);
198	if (rc) {
199		dev_err(&spdev->dev,
200			"reboot notifier registration failed rc %d\n", rc);
201		goto connect_exit;
202	}
203
204	client_thread = kthread_run(cosm_scif_client, NULL, "cosm_client");
205	if (IS_ERR(client_thread)) {
206		rc = PTR_ERR(client_thread);
207		dev_err(&spdev->dev, "%s %d kthread_run rc %d\n",
208			__func__, __LINE__, rc);
209		goto unreg_reboot;
210	}
211	return;
212unreg_reboot:
213	unregister_reboot_notifier(&cosm_reboot);
214connect_exit:
215	cosm_scif_connect_exit();
216exit:
217	client_spdev = NULL;
218}
219
220static void cosm_scif_remove(struct scif_peer_dev *spdev)
221{
222	int rc;
223
224	dev_dbg(&spdev->dev, "%s %d: dnode %d\n",
225		__func__, __LINE__, spdev->dnode);
226
227	if (spdev->dnode)
228		return;
229
230	if (!IS_ERR_OR_NULL(client_thread)) {
231		rc = send_sig(SIGKILL, client_thread, 0);
232		if (rc) {
233			pr_err("%s %d send_sig rc %d\n",
234			       __func__, __LINE__, rc);
235			return;
236		}
237		kthread_stop(client_thread);
238	}
239	unregister_reboot_notifier(&cosm_reboot);
240	cosm_scif_connect_exit();
241	client_spdev = NULL;
242}
243
244static struct scif_client scif_client_cosm = {
245	.name = KBUILD_MODNAME,
246	.probe = cosm_scif_probe,
247	.remove = cosm_scif_remove,
248};
249
250static int __init cosm_client_init(void)
251{
252	int rc = scif_client_register(&scif_client_cosm);
253
254	if (rc)
255		pr_err("scif_client_register failed rc %d\n", rc);
256	return rc;
257}
258
259static void __exit cosm_client_exit(void)
260{
261	scif_client_unregister(&scif_client_cosm);
262}
263
264module_init(cosm_client_init);
265module_exit(cosm_client_exit);
266
267MODULE_AUTHOR("Intel Corporation");
268MODULE_DESCRIPTION("Intel(R) MIC card OS state management client driver");
269MODULE_LICENSE("GPL v2");