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1 | ===================== |
2 | The Linux IPMI Driver | |
3 | ===================== | |
1da177e4 | 4 | |
f5981a5c | 5 | :Author: Corey Minyard <minyard@mvista.com> / <minyard@acm.org> |
1da177e4 LT |
6 | |
7 | The Intelligent Platform Management Interface, or IPMI, is a | |
8 | standard for controlling intelligent devices that monitor a system. | |
9 | It provides for dynamic discovery of sensors in the system and the | |
10 | ability to monitor the sensors and be informed when the sensor's | |
11 | values change or go outside certain boundaries. It also has a | |
dc474c89 | 12 | standardized database for field-replaceable units (FRUs) and a watchdog |
1da177e4 LT |
13 | timer. |
14 | ||
15 | To use this, you need an interface to an IPMI controller in your | |
16 | system (called a Baseboard Management Controller, or BMC) and | |
17 | management software that can use the IPMI system. | |
18 | ||
19 | This document describes how to use the IPMI driver for Linux. If you | |
20 | are not familiar with IPMI itself, see the web site at | |
21 | http://www.intel.com/design/servers/ipmi/index.htm. IPMI is a big | |
22 | subject and I can't cover it all here! | |
23 | ||
24 | Configuration | |
25 | ------------- | |
26 | ||
845e78a1 | 27 | The Linux IPMI driver is modular, which means you have to pick several |
1da177e4 | 28 | things to have it work right depending on your hardware. Most of |
845e78a1 CM |
29 | these are available in the 'Character Devices' menu then the IPMI |
30 | menu. | |
1da177e4 LT |
31 | |
32 | No matter what, you must pick 'IPMI top-level message handler' to use | |
33 | IPMI. What you do beyond that depends on your needs and hardware. | |
34 | ||
35 | The message handler does not provide any user-level interfaces. | |
36 | Kernel code (like the watchdog) can still use it. If you need access | |
37 | from userland, you need to select 'Device interface for IPMI' if you | |
845e78a1 CM |
38 | want access through a device driver. |
39 | ||
40 | The driver interface depends on your hardware. If your system | |
41 | properly provides the SMBIOS info for IPMI, the driver will detect it | |
42 | and just work. If you have a board with a standard interface (These | |
43 | will generally be either "KCS", "SMIC", or "BT", consult your hardware | |
25930707 CM |
44 | manual), choose the 'IPMI SI handler' option. A driver also exists |
45 | for direct I2C access to the IPMI management controller. Some boards | |
46 | support this, but it is unknown if it will work on every board. For | |
47 | this, choose 'IPMI SMBus handler', but be ready to try to do some | |
48 | figuring to see if it will work on your system if the SMBIOS/APCI | |
49 | information is wrong or not present. It is fairly safe to have both | |
50 | these enabled and let the drivers auto-detect what is present. | |
1da177e4 LT |
51 | |
52 | You should generally enable ACPI on your system, as systems with IPMI | |
845e78a1 | 53 | can have ACPI tables describing them. |
1da177e4 LT |
54 | |
55 | If you have a standard interface and the board manufacturer has done | |
56 | their job correctly, the IPMI controller should be automatically | |
845e78a1 CM |
57 | detected (via ACPI or SMBIOS tables) and should just work. Sadly, |
58 | many boards do not have this information. The driver attempts | |
59 | standard defaults, but they may not work. If you fall into this | |
25930707 CM |
60 | situation, you need to read the section below named 'The SI Driver' or |
61 | "The SMBus Driver" on how to hand-configure your system. | |
1da177e4 LT |
62 | |
63 | IPMI defines a standard watchdog timer. You can enable this with the | |
64 | 'IPMI Watchdog Timer' config option. If you compile the driver into | |
65 | the kernel, then via a kernel command-line option you can have the | |
dc474c89 | 66 | watchdog timer start as soon as it initializes. It also have a lot |
1da177e4 LT |
67 | of other options, see the 'Watchdog' section below for more details. |
68 | Note that you can also have the watchdog continue to run if it is | |
69 | closed (by default it is disabled on close). Go into the 'Watchdog | |
70 | Cards' menu, enable 'Watchdog Timer Support', and enable the option | |
71 | 'Disable watchdog shutdown on close'. | |
72 | ||
845e78a1 CM |
73 | IPMI systems can often be powered off using IPMI commands. Select |
74 | 'IPMI Poweroff' to do this. The driver will auto-detect if the system | |
75 | can be powered off by IPMI. It is safe to enable this even if your | |
76 | system doesn't support this option. This works on ATCA systems, the | |
77 | Radisys CPI1 card, and any IPMI system that supports standard chassis | |
78 | management commands. | |
79 | ||
80 | If you want the driver to put an event into the event log on a panic, | |
81 | enable the 'Generate a panic event to all BMCs on a panic' option. If | |
82 | you want the whole panic string put into the event log using OEM | |
83 | events, enable the 'Generate OEM events containing the panic string' | |
84 | option. | |
1da177e4 LT |
85 | |
86 | Basic Design | |
87 | ------------ | |
88 | ||
89 | The Linux IPMI driver is designed to be very modular and flexible, you | |
90 | only need to take the pieces you need and you can use it in many | |
91 | different ways. Because of that, it's broken into many chunks of | |
845e78a1 | 92 | code. These chunks (by module name) are: |
1da177e4 LT |
93 | |
94 | ipmi_msghandler - This is the central piece of software for the IPMI | |
95 | system. It handles all messages, message timing, and responses. The | |
96 | IPMI users tie into this, and the IPMI physical interfaces (called | |
97 | System Management Interfaces, or SMIs) also tie in here. This | |
98 | provides the kernelland interface for IPMI, but does not provide an | |
99 | interface for use by application processes. | |
100 | ||
101 | ipmi_devintf - This provides a userland IOCTL interface for the IPMI | |
102 | driver, each open file for this device ties in to the message handler | |
103 | as an IPMI user. | |
104 | ||
845e78a1 | 105 | ipmi_si - A driver for various system interfaces. This supports KCS, |
25930707 CM |
106 | SMIC, and BT interfaces. Unless you have an SMBus interface or your |
107 | own custom interface, you probably need to use this. | |
108 | ||
109 | ipmi_ssif - A driver for accessing BMCs on the SMBus. It uses the | |
110 | I2C kernel driver's SMBus interfaces to send and receive IPMI messages | |
111 | over the SMBus. | |
1da177e4 | 112 | |
c11daf6a CM |
113 | ipmi_powernv - A driver for access BMCs on POWERNV systems. |
114 | ||
845e78a1 CM |
115 | ipmi_watchdog - IPMI requires systems to have a very capable watchdog |
116 | timer. This driver implements the standard Linux watchdog timer | |
117 | interface on top of the IPMI message handler. | |
118 | ||
119 | ipmi_poweroff - Some systems support the ability to be turned off via | |
120 | IPMI commands. | |
121 | ||
c11daf6a CM |
122 | bt-bmc - This is not part of the main driver, but instead a driver for |
123 | accessing a BMC-side interface of a BT interface. It is used on BMCs | |
124 | running Linux to provide an interface to the host. | |
1da177e4 | 125 | |
c11daf6a | 126 | These are all individually selectable via configuration options. |
1da177e4 LT |
127 | |
128 | Much documentation for the interface is in the include files. The | |
129 | IPMI include files are: | |
130 | ||
1da177e4 LT |
131 | linux/ipmi.h - Contains the user interface and IOCTL interface for IPMI. |
132 | ||
133 | linux/ipmi_smi.h - Contains the interface for system management interfaces | |
134 | (things that interface to IPMI controllers) to use. | |
135 | ||
136 | linux/ipmi_msgdefs.h - General definitions for base IPMI messaging. | |
137 | ||
138 | ||
139 | Addressing | |
140 | ---------- | |
141 | ||
142 | The IPMI addressing works much like IP addresses, you have an overlay | |
f5981a5c | 143 | to handle the different address types. The overlay is:: |
1da177e4 LT |
144 | |
145 | struct ipmi_addr | |
146 | { | |
147 | int addr_type; | |
148 | short channel; | |
149 | char data[IPMI_MAX_ADDR_SIZE]; | |
150 | }; | |
151 | ||
152 | The addr_type determines what the address really is. The driver | |
153 | currently understands two different types of addresses. | |
154 | ||
f5981a5c | 155 | "System Interface" addresses are defined as:: |
1da177e4 LT |
156 | |
157 | struct ipmi_system_interface_addr | |
158 | { | |
159 | int addr_type; | |
160 | short channel; | |
161 | }; | |
162 | ||
163 | and the type is IPMI_SYSTEM_INTERFACE_ADDR_TYPE. This is used for talking | |
164 | straight to the BMC on the current card. The channel must be | |
165 | IPMI_BMC_CHANNEL. | |
166 | ||
167 | Messages that are destined to go out on the IPMB bus use the | |
f5981a5c | 168 | IPMI_IPMB_ADDR_TYPE address type. The format is:: |
1da177e4 LT |
169 | |
170 | struct ipmi_ipmb_addr | |
171 | { | |
172 | int addr_type; | |
173 | short channel; | |
174 | unsigned char slave_addr; | |
175 | unsigned char lun; | |
176 | }; | |
177 | ||
178 | The "channel" here is generally zero, but some devices support more | |
179 | than one channel, it corresponds to the channel as defined in the IPMI | |
180 | spec. | |
181 | ||
182 | ||
183 | Messages | |
184 | -------- | |
185 | ||
f5981a5c | 186 | Messages are defined as:: |
1da177e4 | 187 | |
f5981a5c MCC |
188 | struct ipmi_msg |
189 | { | |
1da177e4 LT |
190 | unsigned char netfn; |
191 | unsigned char lun; | |
192 | unsigned char cmd; | |
193 | unsigned char *data; | |
194 | int data_len; | |
f5981a5c | 195 | }; |
1da177e4 LT |
196 | |
197 | The driver takes care of adding/stripping the header information. The | |
198 | data portion is just the data to be send (do NOT put addressing info | |
199 | here) or the response. Note that the completion code of a response is | |
200 | the first item in "data", it is not stripped out because that is how | |
201 | all the messages are defined in the spec (and thus makes counting the | |
202 | offsets a little easier :-). | |
203 | ||
204 | When using the IOCTL interface from userland, you must provide a block | |
205 | of data for "data", fill it, and set data_len to the length of the | |
206 | block of data, even when receiving messages. Otherwise the driver | |
207 | will have no place to put the message. | |
208 | ||
209 | Messages coming up from the message handler in kernelland will come in | |
f5981a5c | 210 | as:: |
1da177e4 LT |
211 | |
212 | struct ipmi_recv_msg | |
213 | { | |
214 | struct list_head link; | |
215 | ||
216 | /* The type of message as defined in the "Receive Types" | |
217 | defines above. */ | |
218 | int recv_type; | |
219 | ||
220 | ipmi_user_t *user; | |
221 | struct ipmi_addr addr; | |
222 | long msgid; | |
223 | struct ipmi_msg msg; | |
224 | ||
225 | /* Call this when done with the message. It will presumably free | |
226 | the message and do any other necessary cleanup. */ | |
227 | void (*done)(struct ipmi_recv_msg *msg); | |
228 | ||
229 | /* Place-holder for the data, don't make any assumptions about | |
230 | the size or existence of this, since it may change. */ | |
231 | unsigned char msg_data[IPMI_MAX_MSG_LENGTH]; | |
232 | }; | |
233 | ||
234 | You should look at the receive type and handle the message | |
235 | appropriately. | |
236 | ||
237 | ||
238 | The Upper Layer Interface (Message Handler) | |
239 | ------------------------------------------- | |
240 | ||
241 | The upper layer of the interface provides the users with a consistent | |
242 | view of the IPMI interfaces. It allows multiple SMI interfaces to be | |
243 | addressed (because some boards actually have multiple BMCs on them) | |
244 | and the user should not have to care what type of SMI is below them. | |
245 | ||
246 | ||
c11daf6a | 247 | Watching For Interfaces |
f5981a5c | 248 | ^^^^^^^^^^^^^^^^^^^^^^^ |
c11daf6a CM |
249 | |
250 | When your code comes up, the IPMI driver may or may not have detected | |
251 | if IPMI devices exist. So you might have to defer your setup until | |
252 | the device is detected, or you might be able to do it immediately. | |
253 | To handle this, and to allow for discovery, you register an SMI | |
254 | watcher with ipmi_smi_watcher_register() to iterate over interfaces | |
255 | and tell you when they come and go. | |
256 | ||
257 | ||
1da177e4 | 258 | Creating the User |
f5981a5c | 259 | ^^^^^^^^^^^^^^^^^ |
1da177e4 | 260 | |
08f6cd01 | 261 | To use the message handler, you must first create a user using |
1da177e4 LT |
262 | ipmi_create_user. The interface number specifies which SMI you want |
263 | to connect to, and you must supply callback functions to be called | |
264 | when data comes in. The callback function can run at interrupt level, | |
265 | so be careful using the callbacks. This also allows to you pass in a | |
266 | piece of data, the handler_data, that will be passed back to you on | |
267 | all calls. | |
268 | ||
269 | Once you are done, call ipmi_destroy_user() to get rid of the user. | |
270 | ||
271 | From userland, opening the device automatically creates a user, and | |
272 | closing the device automatically destroys the user. | |
273 | ||
274 | ||
275 | Messaging | |
f5981a5c | 276 | ^^^^^^^^^ |
1da177e4 | 277 | |
c11daf6a | 278 | To send a message from kernel-land, the ipmi_request_settime() call does |
1da177e4 LT |
279 | pretty much all message handling. Most of the parameter are |
280 | self-explanatory. However, it takes a "msgid" parameter. This is NOT | |
281 | the sequence number of messages. It is simply a long value that is | |
282 | passed back when the response for the message is returned. You may | |
283 | use it for anything you like. | |
284 | ||
285 | Responses come back in the function pointed to by the ipmi_recv_hndl | |
286 | field of the "handler" that you passed in to ipmi_create_user(). | |
287 | Remember again, these may be running at interrupt level. Remember to | |
288 | look at the receive type, too. | |
289 | ||
290 | From userland, you fill out an ipmi_req_t structure and use the | |
291 | IPMICTL_SEND_COMMAND ioctl. For incoming stuff, you can use select() | |
292 | or poll() to wait for messages to come in. However, you cannot use | |
293 | read() to get them, you must call the IPMICTL_RECEIVE_MSG with the | |
294 | ipmi_recv_t structure to actually get the message. Remember that you | |
295 | must supply a pointer to a block of data in the msg.data field, and | |
296 | you must fill in the msg.data_len field with the size of the data. | |
297 | This gives the receiver a place to actually put the message. | |
298 | ||
299 | If the message cannot fit into the data you provide, you will get an | |
300 | EMSGSIZE error and the driver will leave the data in the receive | |
301 | queue. If you want to get it and have it truncate the message, us | |
302 | the IPMICTL_RECEIVE_MSG_TRUNC ioctl. | |
303 | ||
304 | When you send a command (which is defined by the lowest-order bit of | |
305 | the netfn per the IPMI spec) on the IPMB bus, the driver will | |
306 | automatically assign the sequence number to the command and save the | |
307 | command. If the response is not receive in the IPMI-specified 5 | |
308 | seconds, it will generate a response automatically saying the command | |
309 | timed out. If an unsolicited response comes in (if it was after 5 | |
310 | seconds, for instance), that response will be ignored. | |
311 | ||
312 | In kernelland, after you receive a message and are done with it, you | |
313 | MUST call ipmi_free_recv_msg() on it, or you will leak messages. Note | |
314 | that you should NEVER mess with the "done" field of a message, that is | |
315 | required to properly clean up the message. | |
316 | ||
317 | Note that when sending, there is an ipmi_request_supply_msgs() call | |
318 | that lets you supply the smi and receive message. This is useful for | |
319 | pieces of code that need to work even if the system is out of buffers | |
320 | (the watchdog timer uses this, for instance). You supply your own | |
321 | buffer and own free routines. This is not recommended for normal use, | |
322 | though, since it is tricky to manage your own buffers. | |
323 | ||
324 | ||
325 | Events and Incoming Commands | |
f5981a5c | 326 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
1da177e4 LT |
327 | |
328 | The driver takes care of polling for IPMI events and receiving | |
329 | commands (commands are messages that are not responses, they are | |
330 | commands that other things on the IPMB bus have sent you). To receive | |
331 | these, you must register for them, they will not automatically be sent | |
332 | to you. | |
333 | ||
334 | To receive events, you must call ipmi_set_gets_events() and set the | |
335 | "val" to non-zero. Any events that have been received by the driver | |
336 | since startup will immediately be delivered to the first user that | |
337 | registers for events. After that, if multiple users are registered | |
338 | for events, they will all receive all events that come in. | |
339 | ||
340 | For receiving commands, you have to individually register commands you | |
341 | want to receive. Call ipmi_register_for_cmd() and supply the netfn | |
c69c3127 CM |
342 | and command name for each command you want to receive. You also |
343 | specify a bitmask of the channels you want to receive the command from | |
344 | (or use IPMI_CHAN_ALL for all channels if you don't care). Only one | |
345 | user may be registered for each netfn/cmd/channel, but different users | |
346 | may register for different commands, or the same command if the | |
347 | channel bitmasks do not overlap. | |
1da177e4 LT |
348 | |
349 | From userland, equivalent IOCTLs are provided to do these functions. | |
350 | ||
351 | ||
352 | The Lower Layer (SMI) Interface | |
353 | ------------------------------- | |
354 | ||
355 | As mentioned before, multiple SMI interfaces may be registered to the | |
356 | message handler, each of these is assigned an interface number when | |
357 | they register with the message handler. They are generally assigned | |
358 | in the order they register, although if an SMI unregisters and then | |
359 | another one registers, all bets are off. | |
360 | ||
361 | The ipmi_smi.h defines the interface for management interfaces, see | |
362 | that for more details. | |
363 | ||
364 | ||
365 | The SI Driver | |
366 | ------------- | |
367 | ||
c11daf6a CM |
368 | The SI driver allows KCS, BT, and SMIC interfaces to be configured |
369 | in the system. It discovers interfaces through a host of different | |
370 | methods, depending on the system. | |
371 | ||
372 | You can specify up to four interfaces on the module load line and | |
f5981a5c | 373 | control some module parameters:: |
1da177e4 LT |
374 | |
375 | modprobe ipmi_si.o type=<type1>,<type2>.... | |
376 | ports=<port1>,<port2>... addrs=<addr1>,<addr2>... | |
f2afae46 | 377 | irqs=<irq1>,<irq2>... |
1da177e4 LT |
378 | regspacings=<sp1>,<sp2>,... regsizes=<size1>,<size2>,... |
379 | regshifts=<shift1>,<shift2>,... | |
380 | slave_addrs=<addr1>,<addr2>,... | |
a51f4a81 | 381 | force_kipmid=<enable1>,<enable2>,... |
ae74e823 | 382 | kipmid_max_busy_us=<ustime1>,<ustime2>,... |
b361e27b | 383 | unload_when_empty=[0|1] |
c11daf6a | 384 | trydmi=[0|1] tryacpi=[0|1] |
f2afae46 | 385 | tryplatform=[0|1] trypci=[0|1] |
1da177e4 | 386 | |
f2afae46 | 387 | Each of these except try... items is a list, the first item for the |
1da177e4 LT |
388 | first interface, second item for the second interface, etc. |
389 | ||
390 | The si_type may be either "kcs", "smic", or "bt". If you leave it blank, it | |
391 | defaults to "kcs". | |
392 | ||
f2afae46 | 393 | If you specify addrs as non-zero for an interface, the driver will |
1da177e4 LT |
394 | use the memory address given as the address of the device. This |
395 | overrides si_ports. | |
396 | ||
f2afae46 | 397 | If you specify ports as non-zero for an interface, the driver will |
1da177e4 LT |
398 | use the I/O port given as the device address. |
399 | ||
f2afae46 | 400 | If you specify irqs as non-zero for an interface, the driver will |
1da177e4 LT |
401 | attempt to use the given interrupt for the device. |
402 | ||
f2afae46 CM |
403 | The other try... items disable discovery by their corresponding |
404 | names. These are all enabled by default, set them to zero to disable | |
405 | them. The tryplatform disables openfirmware. | |
406 | ||
1da177e4 LT |
407 | The next three parameters have to do with register layout. The |
408 | registers used by the interfaces may not appear at successive | |
409 | locations and they may not be in 8-bit registers. These parameters | |
410 | allow the layout of the data in the registers to be more precisely | |
411 | specified. | |
412 | ||
413 | The regspacings parameter give the number of bytes between successive | |
414 | register start addresses. For instance, if the regspacing is set to 4 | |
415 | and the start address is 0xca2, then the address for the second | |
416 | register would be 0xca6. This defaults to 1. | |
417 | ||
418 | The regsizes parameter gives the size of a register, in bytes. The | |
419 | data used by IPMI is 8-bits wide, but it may be inside a larger | |
420 | register. This parameter allows the read and write type to specified. | |
421 | It may be 1, 2, 4, or 8. The default is 1. | |
422 | ||
423 | Since the register size may be larger than 32 bits, the IPMI data may not | |
424 | be in the lower 8 bits. The regshifts parameter give the amount to shift | |
425 | the data to get to the actual IPMI data. | |
426 | ||
427 | The slave_addrs specifies the IPMI address of the local BMC. This is | |
428 | usually 0x20 and the driver defaults to that, but in case it's not, it | |
429 | can be specified when the driver starts up. | |
430 | ||
a51f4a81 CM |
431 | The force_ipmid parameter forcefully enables (if set to 1) or disables |
432 | (if set to 0) the kernel IPMI daemon. Normally this is auto-detected | |
433 | by the driver, but systems with broken interrupts might need an enable, | |
434 | or users that don't want the daemon (don't need the performance, don't | |
435 | want the CPU hit) can disable it. | |
436 | ||
b361e27b CM |
437 | If unload_when_empty is set to 1, the driver will be unloaded if it |
438 | doesn't find any interfaces or all the interfaces fail to work. The | |
439 | default is one. Setting to 0 is useful with the hotmod, but is | |
440 | obviously only useful for modules. | |
441 | ||
a51f4a81 | 442 | When compiled into the kernel, the parameters can be specified on the |
f5981a5c | 443 | kernel command line as:: |
1da177e4 LT |
444 | |
445 | ipmi_si.type=<type1>,<type2>... | |
446 | ipmi_si.ports=<port1>,<port2>... ipmi_si.addrs=<addr1>,<addr2>... | |
c11daf6a | 447 | ipmi_si.irqs=<irq1>,<irq2>... |
1da177e4 LT |
448 | ipmi_si.regspacings=<sp1>,<sp2>,... |
449 | ipmi_si.regsizes=<size1>,<size2>,... | |
450 | ipmi_si.regshifts=<shift1>,<shift2>,... | |
451 | ipmi_si.slave_addrs=<addr1>,<addr2>,... | |
a51f4a81 | 452 | ipmi_si.force_kipmid=<enable1>,<enable2>,... |
ae74e823 | 453 | ipmi_si.kipmid_max_busy_us=<ustime1>,<ustime2>,... |
1da177e4 LT |
454 | |
455 | It works the same as the module parameters of the same names. | |
456 | ||
650dd0c7 CM |
457 | If your IPMI interface does not support interrupts and is a KCS or |
458 | SMIC interface, the IPMI driver will start a kernel thread for the | |
459 | interface to help speed things up. This is a low-priority kernel | |
460 | thread that constantly polls the IPMI driver while an IPMI operation | |
461 | is in progress. The force_kipmid module parameter will all the user to | |
462 | force this thread on or off. If you force it off and don't have | |
463 | interrupts, the driver will run VERY slowly. Don't blame me, | |
1da177e4 LT |
464 | these interfaces suck. |
465 | ||
ae74e823 MW |
466 | Unfortunately, this thread can use a lot of CPU depending on the |
467 | interface's performance. This can waste a lot of CPU and cause | |
468 | various issues with detecting idle CPU and using extra power. To | |
469 | avoid this, the kipmid_max_busy_us sets the maximum amount of time, in | |
470 | microseconds, that kipmid will spin before sleeping for a tick. This | |
471 | value sets a balance between performance and CPU waste and needs to be | |
472 | tuned to your needs. Maybe, someday, auto-tuning will be added, but | |
473 | that's not a simple thing and even the auto-tuning would need to be | |
474 | tuned to the user's desired performance. | |
475 | ||
b361e27b CM |
476 | The driver supports a hot add and remove of interfaces. This way, |
477 | interfaces can be added or removed after the kernel is up and running. | |
650dd0c7 CM |
478 | This is done using /sys/modules/ipmi_si/parameters/hotmod, which is a |
479 | write-only parameter. You write a string to this interface. The string | |
f5981a5c MCC |
480 | has the format:: |
481 | ||
b361e27b | 482 | <op1>[:op2[:op3...]] |
f5981a5c MCC |
483 | |
484 | The "op"s are:: | |
485 | ||
b361e27b | 486 | add|remove,kcs|bt|smic,mem|i/o,<address>[,<opt1>[,<opt2>[,...]]] |
f5981a5c MCC |
487 | |
488 | You can specify more than one interface on the line. The "opt"s are:: | |
489 | ||
b361e27b CM |
490 | rsp=<regspacing> |
491 | rsi=<regsize> | |
492 | rsh=<regshift> | |
493 | irq=<irq> | |
494 | ipmb=<ipmb slave addr> | |
f5981a5c | 495 | |
b361e27b CM |
496 | and these have the same meanings as discussed above. Note that you |
497 | can also use this on the kernel command line for a more compact format | |
498 | for specifying an interface. Note that when removing an interface, | |
499 | only the first three parameters (si type, address type, and address) | |
500 | are used for the comparison. Any options are ignored for removing. | |
1da177e4 | 501 | |
25930707 CM |
502 | The SMBus Driver (SSIF) |
503 | ----------------------- | |
504 | ||
505 | The SMBus driver allows up to 4 SMBus devices to be configured in the | |
506 | system. By default, the driver will only register with something it | |
507 | finds in DMI or ACPI tables. You can change this | |
f5981a5c | 508 | at module load time (for a module) with:: |
25930707 CM |
509 | |
510 | modprobe ipmi_ssif.o | |
511 | addr=<i2caddr1>[,<i2caddr2>[,...]] | |
512 | adapter=<adapter1>[,<adapter2>[...]] | |
513 | dbg=<flags1>,<flags2>... | |
c11daf6a CM |
514 | slave_addrs=<addr1>,<addr2>,... |
515 | tryacpi=[0|1] trydmi=[0|1] | |
25930707 CM |
516 | [dbg_probe=1] |
517 | ||
518 | The addresses are normal I2C addresses. The adapter is the string | |
519 | name of the adapter, as shown in /sys/class/i2c-adapter/i2c-<n>/name. | |
b0e9aaa9 CM |
520 | It is *NOT* i2c-<n> itself. Also, the comparison is done ignoring |
521 | spaces, so if the name is "This is an I2C chip" you can say | |
522 | adapter_name=ThisisanI2cchip. This is because it's hard to pass in | |
523 | spaces in kernel parameters. | |
25930707 CM |
524 | |
525 | The debug flags are bit flags for each BMC found, they are: | |
526 | IPMI messages: 1, driver state: 2, timing: 4, I2C probe: 8 | |
527 | ||
c11daf6a CM |
528 | The tryxxx parameters can be used to disable detecting interfaces |
529 | from various sources. | |
530 | ||
25930707 CM |
531 | Setting dbg_probe to 1 will enable debugging of the probing and |
532 | detection process for BMCs on the SMBusses. | |
533 | ||
534 | The slave_addrs specifies the IPMI address of the local BMC. This is | |
535 | usually 0x20 and the driver defaults to that, but in case it's not, it | |
536 | can be specified when the driver starts up. | |
537 | ||
538 | Discovering the IPMI compliant BMC on the SMBus can cause devices on | |
539 | the I2C bus to fail. The SMBus driver writes a "Get Device ID" IPMI | |
540 | message as a block write to the I2C bus and waits for a response. | |
541 | This action can be detrimental to some I2C devices. It is highly | |
542 | recommended that the known I2C address be given to the SMBus driver in | |
543 | the smb_addr parameter unless you have DMI or ACPI data to tell the | |
544 | driver what to use. | |
545 | ||
546 | When compiled into the kernel, the addresses can be specified on the | |
f5981a5c | 547 | kernel command line as:: |
25930707 CM |
548 | |
549 | ipmb_ssif.addr=<i2caddr1>[,<i2caddr2>[...]] | |
550 | ipmi_ssif.adapter=<adapter1>[,<adapter2>[...]] | |
551 | ipmi_ssif.dbg=<flags1>[,<flags2>[...]] | |
552 | ipmi_ssif.dbg_probe=1 | |
c11daf6a CM |
553 | ipmi_ssif.slave_addrs=<addr1>[,<addr2>[...]] |
554 | ipmi_ssif.tryacpi=[0|1] ipmi_ssif.trydmi=[0|1] | |
25930707 CM |
555 | |
556 | These are the same options as on the module command line. | |
557 | ||
558 | The I2C driver does not support non-blocking access or polling, so | |
559 | this driver cannod to IPMI panic events, extend the watchdog at panic | |
560 | time, or other panic-related IPMI functions without special kernel | |
561 | patches and driver modifications. You can get those at the openipmi | |
562 | web page. | |
563 | ||
564 | The driver supports a hot add and remove of interfaces through the I2C | |
565 | sysfs interface. | |
1da177e4 LT |
566 | |
567 | Other Pieces | |
568 | ------------ | |
569 | ||
37bf501b ZY |
570 | Get the detailed info related with the IPMI device |
571 | -------------------------------------------------- | |
572 | ||
573 | Some users need more detailed information about a device, like where | |
574 | the address came from or the raw base device for the IPMI interface. | |
575 | You can use the IPMI smi_watcher to catch the IPMI interfaces as they | |
576 | come or go, and to grab the information, you can use the function | |
f5981a5c | 577 | ipmi_get_smi_info(), which returns the following structure:: |
37bf501b | 578 | |
f5981a5c | 579 | struct ipmi_smi_info { |
37bf501b ZY |
580 | enum ipmi_addr_src addr_src; |
581 | struct device *dev; | |
582 | union { | |
583 | struct { | |
584 | void *acpi_handle; | |
585 | } acpi_info; | |
586 | } addr_info; | |
f5981a5c | 587 | }; |
37bf501b ZY |
588 | |
589 | Currently special info for only for SI_ACPI address sources is | |
590 | returned. Others may be added as necessary. | |
591 | ||
592 | Note that the dev pointer is included in the above structure, and | |
593 | assuming ipmi_smi_get_info returns success, you must call put_device | |
594 | on the dev pointer. | |
595 | ||
596 | ||
1da177e4 LT |
597 | Watchdog |
598 | -------- | |
599 | ||
600 | A watchdog timer is provided that implements the Linux-standard | |
601 | watchdog timer interface. It has three module parameters that can be | |
f5981a5c | 602 | used to control it:: |
1da177e4 LT |
603 | |
604 | modprobe ipmi_watchdog timeout=<t> pretimeout=<t> action=<action type> | |
605 | preaction=<preaction type> preop=<preop type> start_now=x | |
c7f42c63 | 606 | nowayout=x ifnum_to_use=n panic_wdt_timeout=<t> |
b2c03941 CM |
607 | |
608 | ifnum_to_use specifies which interface the watchdog timer should use. | |
609 | The default is -1, which means to pick the first one registered. | |
1da177e4 LT |
610 | |
611 | The timeout is the number of seconds to the action, and the pretimeout | |
612 | is the amount of seconds before the reset that the pre-timeout panic will | |
613 | occur (if pretimeout is zero, then pretimeout will not be enabled). Note | |
614 | that the pretimeout is the time before the final timeout. So if the | |
615 | timeout is 50 seconds and the pretimeout is 10 seconds, then the pretimeout | |
c7f42c63 JYF |
616 | will occur in 40 second (10 seconds before the timeout). The panic_wdt_timeout |
617 | is the value of timeout which is set on kernel panic, in order to let actions | |
618 | such as kdump to occur during panic. | |
1da177e4 LT |
619 | |
620 | The action may be "reset", "power_cycle", or "power_off", and | |
621 | specifies what to do when the timer times out, and defaults to | |
622 | "reset". | |
623 | ||
624 | The preaction may be "pre_smi" for an indication through the SMI | |
625 | interface, "pre_int" for an indication through the SMI with an | |
626 | interrupts, and "pre_nmi" for a NMI on a preaction. This is how | |
627 | the driver is informed of the pretimeout. | |
628 | ||
629 | The preop may be set to "preop_none" for no operation on a pretimeout, | |
630 | "preop_panic" to set the preoperation to panic, or "preop_give_data" | |
631 | to provide data to read from the watchdog device when the pretimeout | |
632 | occurs. A "pre_nmi" setting CANNOT be used with "preop_give_data" | |
633 | because you can't do data operations from an NMI. | |
634 | ||
635 | When preop is set to "preop_give_data", one byte comes ready to read | |
636 | on the device when the pretimeout occurs. Select and fasync work on | |
637 | the device, as well. | |
638 | ||
639 | If start_now is set to 1, the watchdog timer will start running as | |
640 | soon as the driver is loaded. | |
641 | ||
642 | If nowayout is set to 1, the watchdog timer will not stop when the | |
643 | watchdog device is closed. The default value of nowayout is true | |
644 | if the CONFIG_WATCHDOG_NOWAYOUT option is enabled, or false if not. | |
645 | ||
646 | When compiled into the kernel, the kernel command line is available | |
f5981a5c | 647 | for configuring the watchdog:: |
1da177e4 LT |
648 | |
649 | ipmi_watchdog.timeout=<t> ipmi_watchdog.pretimeout=<t> | |
650 | ipmi_watchdog.action=<action type> | |
651 | ipmi_watchdog.preaction=<preaction type> | |
652 | ipmi_watchdog.preop=<preop type> | |
653 | ipmi_watchdog.start_now=x | |
654 | ipmi_watchdog.nowayout=x | |
c7f42c63 | 655 | ipmi_watchdog.panic_wdt_timeout=<t> |
1da177e4 LT |
656 | |
657 | The options are the same as the module parameter options. | |
658 | ||
659 | The watchdog will panic and start a 120 second reset timeout if it | |
660 | gets a pre-action. During a panic or a reboot, the watchdog will | |
661 | start a 120 timer if it is running to make sure the reboot occurs. | |
662 | ||
612b5a8d CM |
663 | Note that if you use the NMI preaction for the watchdog, you MUST NOT |
664 | use the nmi watchdog. There is no reasonable way to tell if an NMI | |
665 | comes from the IPMI controller, so it must assume that if it gets an | |
666 | otherwise unhandled NMI, it must be from IPMI and it will panic | |
667 | immediately. | |
1da177e4 LT |
668 | |
669 | Once you open the watchdog timer, you must write a 'V' character to the | |
670 | device to close it, or the timer will not stop. This is a new semantic | |
671 | for the driver, but makes it consistent with the rest of the watchdog | |
672 | drivers in Linux. | |
845e78a1 CM |
673 | |
674 | ||
675 | Panic Timeouts | |
676 | -------------- | |
677 | ||
678 | The OpenIPMI driver supports the ability to put semi-custom and custom | |
679 | events in the system event log if a panic occurs. if you enable the | |
680 | 'Generate a panic event to all BMCs on a panic' option, you will get | |
681 | one event on a panic in a standard IPMI event format. If you enable | |
682 | the 'Generate OEM events containing the panic string' option, you will | |
683 | also get a bunch of OEM events holding the panic string. | |
684 | ||
685 | ||
686 | The field settings of the events are: | |
f5981a5c | 687 | |
845e78a1 CM |
688 | * Generator ID: 0x21 (kernel) |
689 | * EvM Rev: 0x03 (this event is formatting in IPMI 1.0 format) | |
690 | * Sensor Type: 0x20 (OS critical stop sensor) | |
691 | * Sensor #: The first byte of the panic string (0 if no panic string) | |
692 | * Event Dir | Event Type: 0x6f (Assertion, sensor-specific event info) | |
693 | * Event Data 1: 0xa1 (Runtime stop in OEM bytes 2 and 3) | |
694 | * Event data 2: second byte of panic string | |
695 | * Event data 3: third byte of panic string | |
f5981a5c | 696 | |
845e78a1 CM |
697 | See the IPMI spec for the details of the event layout. This event is |
698 | always sent to the local management controller. It will handle routing | |
699 | the message to the right place | |
700 | ||
701 | Other OEM events have the following format: | |
f5981a5c MCC |
702 | |
703 | * Record ID (bytes 0-1): Set by the SEL. | |
704 | * Record type (byte 2): 0xf0 (OEM non-timestamped) | |
705 | * byte 3: The slave address of the card saving the panic | |
706 | * byte 4: A sequence number (starting at zero) | |
707 | The rest of the bytes (11 bytes) are the panic string. If the panic string | |
708 | is longer than 11 bytes, multiple messages will be sent with increasing | |
709 | sequence numbers. | |
845e78a1 CM |
710 | |
711 | Because you cannot send OEM events using the standard interface, this | |
712 | function will attempt to find an SEL and add the events there. It | |
713 | will first query the capabilities of the local management controller. | |
714 | If it has an SEL, then they will be stored in the SEL of the local | |
715 | management controller. If not, and the local management controller is | |
716 | an event generator, the event receiver from the local management | |
717 | controller will be queried and the events sent to the SEL on that | |
718 | device. Otherwise, the events go nowhere since there is nowhere to | |
719 | send them. | |
3b625943 CM |
720 | |
721 | ||
722 | Poweroff | |
723 | -------- | |
724 | ||
725 | If the poweroff capability is selected, the IPMI driver will install | |
726 | a shutdown function into the standard poweroff function pointer. This | |
727 | is in the ipmi_poweroff module. When the system requests a powerdown, | |
728 | it will send the proper IPMI commands to do this. This is supported on | |
729 | several platforms. | |
730 | ||
8c702e16 CM |
731 | There is a module parameter named "poweroff_powercycle" that may |
732 | either be zero (do a power down) or non-zero (do a power cycle, power | |
733 | the system off, then power it on in a few seconds). Setting | |
734 | ipmi_poweroff.poweroff_control=x will do the same thing on the kernel | |
735 | command line. The parameter is also available via the proc filesystem | |
736 | in /proc/sys/dev/ipmi/poweroff_powercycle. Note that if the system | |
737 | does not support power cycling, it will always do the power off. | |
3b625943 | 738 | |
b2c03941 CM |
739 | The "ifnum_to_use" parameter specifies which interface the poweroff |
740 | code should use. The default is -1, which means to pick the first one | |
741 | registered. | |
742 | ||
3b625943 CM |
743 | Note that if you have ACPI enabled, the system will prefer using ACPI to |
744 | power off. |