1 // SPDX-License-Identifier: GPL-2.0
4 * Driver to talk to a remote management controller on IPMB.
7 #include <linux/acpi.h>
8 #include <linux/errno.h>
10 #include <linux/miscdevice.h>
11 #include <linux/module.h>
12 #include <linux/mutex.h>
13 #include <linux/poll.h>
14 #include <linux/slab.h>
15 #include <linux/spinlock.h>
16 #include <linux/semaphore.h>
17 #include <linux/kthread.h>
18 #include <linux/wait.h>
19 #include <linux/ipmi_msgdefs.h>
20 #include <linux/ipmi_smi.h>
22 #define DEVICE_NAME "ipmi-ipmb"
24 static int bmcaddr = 0x20;
25 module_param(bmcaddr, int, 0644);
26 MODULE_PARM_DESC(bmcaddr, "Address to use for BMC.");
28 static unsigned int retry_time_ms = 250;
29 module_param(retry_time_ms, uint, 0644);
30 MODULE_PARM_DESC(max_retries, "Timeout time between retries, in milliseconds.");
32 static unsigned int max_retries = 1;
33 module_param(max_retries, uint, 0644);
34 MODULE_PARM_DESC(max_retries, "Max resends of a command before timing out.");
36 /* Add room for the two slave addresses, two checksums, and rqSeq. */
37 #define IPMB_MAX_MSG_LEN (IPMI_MAX_MSG_LENGTH + 5)
39 struct ipmi_ipmb_dev {
40 struct ipmi_smi *intf;
41 struct i2c_client *client;
42 struct i2c_client *slave;
44 struct ipmi_smi_handlers handlers;
54 struct ipmi_smi_msg *next_msg;
55 struct ipmi_smi_msg *working_msg;
57 /* Transmit thread. */
58 struct task_struct *thread;
59 struct semaphore wake_thread;
60 struct semaphore got_rsp;
64 u8 xmitmsg[IPMB_MAX_MSG_LEN];
67 u8 rcvmsg[IPMB_MAX_MSG_LEN];
72 static bool valid_ipmb(struct ipmi_ipmb_dev *iidev)
74 u8 *msg = iidev->rcvmsg;
80 /* Minimum message size. */
81 if (iidev->rcvlen < 7)
84 /* Is it a response? */
87 /* Response messages have an added completion code. */
88 if (iidev->rcvlen < 8)
92 if (ipmb_checksum(msg, 3) != 0)
94 if (ipmb_checksum(msg + 3, iidev->rcvlen - 3) != 0)
100 static void ipmi_ipmb_check_msg_done(struct ipmi_ipmb_dev *iidev)
102 struct ipmi_smi_msg *imsg = NULL;
103 u8 *msg = iidev->rcvmsg;
107 if (iidev->rcvlen == 0)
109 if (!valid_ipmb(iidev))
112 is_cmd = ((msg[1] >> 2) & 1) == 0;
115 /* Ignore commands until we are up. */
119 /* It's a command, allocate a message for it. */
120 imsg = ipmi_alloc_smi_msg();
123 imsg->type = IPMI_SMI_MSG_TYPE_IPMB_DIRECT;
126 spin_lock_irqsave(&iidev->lock, flags);
127 if (iidev->working_msg) {
128 u8 seq = msg[4] >> 2;
129 bool xmit_rsp = (iidev->working_msg->data[0] >> 2) & 1;
132 * Responses should carry the sequence we sent
133 * them with. If it's a transmitted response,
134 * ignore it. And if the message hasn't been
135 * transmitted, ignore it.
137 if (!xmit_rsp && seq == iidev->curr_seq) {
138 iidev->curr_seq = (iidev->curr_seq + 1) & 0x3f;
140 imsg = iidev->working_msg;
141 iidev->working_msg = NULL;
144 spin_unlock_irqrestore(&iidev->lock, flags);
150 if (imsg->type == IPMI_SMI_MSG_TYPE_IPMB_DIRECT) {
151 imsg->rsp[0] = msg[1]; /* NetFn/LUN */
153 * Keep the source address, rqSeq. Drop the trailing
156 memcpy(imsg->rsp + 1, msg + 3, iidev->rcvlen - 4);
157 imsg->rsp_size = iidev->rcvlen - 3;
159 imsg->rsp[0] = msg[1]; /* NetFn/LUN */
161 * Skip the source address, rqSeq. Drop the trailing
164 memcpy(imsg->rsp + 1, msg + 5, iidev->rcvlen - 6);
165 imsg->rsp_size = iidev->rcvlen - 5;
167 ipmi_smi_msg_received(iidev->intf, imsg);
172 iidev->overrun = false;
177 * The IPMB protocol only supports i2c writes so there is no need to
178 * support I2C_SLAVE_READ* events, except to know if the other end has
179 * issued a read without going to stop mode.
181 static int ipmi_ipmb_slave_cb(struct i2c_client *client,
182 enum i2c_slave_event event, u8 *val)
184 struct ipmi_ipmb_dev *iidev = i2c_get_clientdata(client);
187 case I2C_SLAVE_WRITE_REQUESTED:
188 ipmi_ipmb_check_msg_done(iidev);
190 * First byte is the slave address, to ease the checksum
193 iidev->rcvmsg[0] = client->addr << 1;
197 case I2C_SLAVE_WRITE_RECEIVED:
198 if (iidev->rcvlen >= sizeof(iidev->rcvmsg))
199 iidev->overrun = true;
201 iidev->rcvmsg[iidev->rcvlen++] = *val;
204 case I2C_SLAVE_READ_REQUESTED:
206 ipmi_ipmb_check_msg_done(iidev);
209 case I2C_SLAVE_READ_PROCESSED:
216 static void ipmi_ipmb_send_response(struct ipmi_ipmb_dev *iidev,
217 struct ipmi_smi_msg *msg, u8 cc)
219 if ((msg->data[0] >> 2) & 1) {
221 * It's a response being sent, we needto return a
222 * response response. Fake a send msg command
223 * response with channel 0. This will always be ipmb
226 msg->data[0] = (IPMI_NETFN_APP_REQUEST | 1) << 2;
227 msg->data[3] = IPMI_SEND_MSG_CMD;
231 msg->rsp[0] = msg->data[0] | (1 << 2);
232 if (msg->type == IPMI_SMI_MSG_TYPE_IPMB_DIRECT) {
233 msg->rsp[1] = msg->data[1];
234 msg->rsp[2] = msg->data[2];
235 msg->rsp[3] = msg->data[3];
239 msg->rsp[1] = msg->data[1];
243 ipmi_smi_msg_received(iidev->intf, msg);
246 static void ipmi_ipmb_format_for_xmit(struct ipmi_ipmb_dev *iidev,
247 struct ipmi_smi_msg *msg)
249 if (msg->type == IPMI_SMI_MSG_TYPE_IPMB_DIRECT) {
250 iidev->xmitmsg[0] = msg->data[1];
251 iidev->xmitmsg[1] = msg->data[0];
252 memcpy(iidev->xmitmsg + 4, msg->data + 2, msg->data_size - 2);
253 iidev->xmitlen = msg->data_size + 2;
255 iidev->xmitmsg[0] = iidev->bmcaddr;
256 iidev->xmitmsg[1] = msg->data[0];
257 iidev->xmitmsg[4] = 0;
258 memcpy(iidev->xmitmsg + 5, msg->data + 1, msg->data_size - 1);
259 iidev->xmitlen = msg->data_size + 4;
261 iidev->xmitmsg[3] = iidev->slave->addr << 1;
262 if (((msg->data[0] >> 2) & 1) == 0)
263 /* If it's a command, put in our own sequence number. */
264 iidev->xmitmsg[4] = ((iidev->xmitmsg[4] & 0x03) |
265 (iidev->curr_seq << 2));
267 /* Now add on the final checksums. */
268 iidev->xmitmsg[2] = ipmb_checksum(iidev->xmitmsg, 2);
269 iidev->xmitmsg[iidev->xmitlen] =
270 ipmb_checksum(iidev->xmitmsg + 3, iidev->xmitlen - 3);
274 static int ipmi_ipmb_thread(void *data)
276 struct ipmi_ipmb_dev *iidev = data;
278 while (!kthread_should_stop()) {
280 struct i2c_msg i2c_msg;
281 struct ipmi_smi_msg *msg = NULL;
283 unsigned int retries = 0;
285 /* Wait for a message to send */
286 ret = down_interruptible(&iidev->wake_thread);
292 spin_lock_irqsave(&iidev->lock, flags);
293 if (iidev->next_msg) {
294 msg = iidev->next_msg;
295 iidev->next_msg = NULL;
297 spin_unlock_irqrestore(&iidev->lock, flags);
301 ipmi_ipmb_format_for_xmit(iidev, msg);
304 i2c_msg.len = iidev->xmitlen - 1;
305 if (i2c_msg.len > 32) {
306 ipmi_ipmb_send_response(iidev, msg,
307 IPMI_REQ_LEN_EXCEEDED_ERR);
311 i2c_msg.addr = iidev->xmitmsg[0] >> 1;
313 i2c_msg.buf = iidev->xmitmsg + 1;
315 /* Rely on i2c_transfer for a barrier. */
316 iidev->working_msg = msg;
318 ret = i2c_transfer(iidev->client->adapter, &i2c_msg, 1);
320 if ((msg->data[0] >> 2) & 1) {
322 * It's a response, nothing will be returned
326 iidev->working_msg = NULL;
327 ipmi_ipmb_send_response(iidev, msg,
328 ret < 0 ? IPMI_BUS_ERR : 0);
332 iidev->working_msg = NULL;
333 ipmi_ipmb_send_response(iidev, msg, IPMI_BUS_ERR);
337 /* A command was sent, wait for its response. */
338 ret = down_timeout(&iidev->got_rsp,
339 msecs_to_jiffies(iidev->retry_time_ms));
342 * Grab the message if we can. If the handler hasn't
343 * already handled it, the message will still be there.
345 spin_lock_irqsave(&iidev->lock, flags);
346 msg = iidev->working_msg;
347 iidev->working_msg = NULL;
348 spin_unlock_irqrestore(&iidev->lock, flags);
352 * If working_msg is not set and we timed out,
353 * that means the message grabbed by
354 * check_msg_done before we could grab it
355 * here. Wait again for check_msg_done to up
358 down(&iidev->got_rsp);
359 } else if (msg && ++retries <= iidev->max_retries) {
360 spin_lock_irqsave(&iidev->lock, flags);
361 iidev->working_msg = msg;
362 spin_unlock_irqrestore(&iidev->lock, flags);
367 ipmi_ipmb_send_response(iidev, msg, IPMI_TIMEOUT_ERR);
371 /* Return an unspecified error. */
372 ipmi_ipmb_send_response(iidev, iidev->next_msg, 0xff);
377 static int ipmi_ipmb_start_processing(void *send_info,
378 struct ipmi_smi *new_intf)
380 struct ipmi_ipmb_dev *iidev = send_info;
382 iidev->intf = new_intf;
387 static void ipmi_ipmb_stop_thread(struct ipmi_ipmb_dev *iidev)
390 struct task_struct *t = iidev->thread;
392 iidev->thread = NULL;
393 iidev->stopping = true;
394 up(&iidev->wake_thread);
400 static void ipmi_ipmb_shutdown(void *send_info)
402 struct ipmi_ipmb_dev *iidev = send_info;
404 ipmi_ipmb_stop_thread(iidev);
407 static void ipmi_ipmb_sender(void *send_info,
408 struct ipmi_smi_msg *msg)
410 struct ipmi_ipmb_dev *iidev = send_info;
413 spin_lock_irqsave(&iidev->lock, flags);
414 BUG_ON(iidev->next_msg);
416 iidev->next_msg = msg;
417 spin_unlock_irqrestore(&iidev->lock, flags);
419 up(&iidev->wake_thread);
422 static void ipmi_ipmb_request_events(void *send_info)
424 /* We don't fetch events here. */
427 static int ipmi_ipmb_remove(struct i2c_client *client)
429 struct ipmi_ipmb_dev *iidev = i2c_get_clientdata(client);
432 i2c_slave_unregister(iidev->slave);
433 if (iidev->slave != iidev->client)
434 i2c_unregister_device(iidev->slave);
437 iidev->client = NULL;
438 ipmi_ipmb_stop_thread(iidev);
440 ipmi_unregister_smi(iidev->intf);
445 static int ipmi_ipmb_probe(struct i2c_client *client)
447 struct device *dev = &client->dev;
448 struct ipmi_ipmb_dev *iidev;
449 struct device_node *slave_np;
450 struct i2c_adapter *slave_adap = NULL;
451 struct i2c_client *slave = NULL;
454 iidev = devm_kzalloc(&client->dev, sizeof(*iidev), GFP_KERNEL);
458 if (of_property_read_u8(dev->of_node, "bmcaddr", &iidev->bmcaddr) != 0)
459 iidev->bmcaddr = bmcaddr;
460 if (iidev->bmcaddr == 0 || iidev->bmcaddr & 1) {
461 /* Can't have the write bit set. */
462 dev_notice(&client->dev,
463 "Invalid bmc address value %2.2x\n", iidev->bmcaddr);
467 if (of_property_read_u32(dev->of_node, "retry-time",
468 &iidev->retry_time_ms) != 0)
469 iidev->retry_time_ms = retry_time_ms;
471 if (of_property_read_u32(dev->of_node, "max-retries",
472 &iidev->max_retries) != 0)
473 iidev->max_retries = max_retries;
475 slave_np = of_parse_phandle(dev->of_node, "slave-dev", 0);
477 slave_adap = of_get_i2c_adapter_by_node(slave_np);
478 of_node_put(slave_np);
480 dev_notice(&client->dev,
481 "Could not find slave adapter\n");
486 iidev->client = client;
489 struct i2c_board_info binfo;
491 memset(&binfo, 0, sizeof(binfo));
492 strscpy(binfo.type, "ipmb-slave", I2C_NAME_SIZE);
493 binfo.addr = client->addr;
494 binfo.flags = I2C_CLIENT_SLAVE;
495 slave = i2c_new_client_device(slave_adap, &binfo);
496 i2c_put_adapter(slave_adap);
499 dev_notice(&client->dev,
500 "Could not allocate slave device: %d\n", rv);
503 i2c_set_clientdata(slave, iidev);
507 i2c_set_clientdata(client, iidev);
508 slave->flags |= I2C_CLIENT_SLAVE;
510 rv = i2c_slave_register(slave, ipmi_ipmb_slave_cb);
513 iidev->slave = slave;
516 iidev->handlers.flags = IPMI_SMI_CAN_HANDLE_IPMB_DIRECT;
517 iidev->handlers.start_processing = ipmi_ipmb_start_processing;
518 iidev->handlers.shutdown = ipmi_ipmb_shutdown;
519 iidev->handlers.sender = ipmi_ipmb_sender;
520 iidev->handlers.request_events = ipmi_ipmb_request_events;
522 spin_lock_init(&iidev->lock);
523 sema_init(&iidev->wake_thread, 0);
524 sema_init(&iidev->got_rsp, 0);
526 iidev->thread = kthread_run(ipmi_ipmb_thread, iidev,
527 "kipmb%4.4x", client->addr);
528 if (IS_ERR(iidev->thread)) {
529 rv = PTR_ERR(iidev->thread);
530 dev_notice(&client->dev,
531 "Could not start kernel thread: error %d\n", rv);
535 rv = ipmi_register_smi(&iidev->handlers,
545 if (slave && slave != client)
546 i2c_unregister_device(slave);
547 ipmi_ipmb_remove(client);
552 static const struct of_device_id of_ipmi_ipmb_match[] = {
553 { .type = "ipmi", .compatible = DEVICE_NAME },
556 MODULE_DEVICE_TABLE(of, of_ipmi_ipmb_match);
558 #define of_ipmi_ipmb_match NULL
561 static const struct i2c_device_id ipmi_ipmb_id[] = {
565 MODULE_DEVICE_TABLE(i2c, ipmi_ipmb_id);
567 static struct i2c_driver ipmi_ipmb_driver = {
568 .class = I2C_CLASS_HWMON,
571 .of_match_table = of_ipmi_ipmb_match,
573 .probe_new = ipmi_ipmb_probe,
574 .remove = ipmi_ipmb_remove,
575 .id_table = ipmi_ipmb_id,
577 module_i2c_driver(ipmi_ipmb_driver);
579 MODULE_AUTHOR("Corey Minyard");
580 MODULE_DESCRIPTION("IPMI IPMB driver");
581 MODULE_LICENSE("GPL v2");