ipmi: Update documentation

I2C kernel driver's SMBus interfaces to send and receive IPMI messages

over the SMBus.

ipmi_powernv - A driver for access BMCs on POWERNV systems.

ipmi_watchdog - IPMI requires systems to have a very capable watchdog

timer.  This driver implements the standard Linux watchdog timer

interface on top of the IPMI message handler.

ipmi_poweroff - Some systems support the ability to be turned off via

IPMI commands.

These are all individually selectable via configuration options.

bt-bmc - This is not part of the main driver, but instead a driver for

accessing a BMC-side interface of a BT interface.  It is used on BMCs

running Linux to provide an interface to the host.

Note that the KCS-only interface has been removed.  The af_ipmi driver

is no longer supported and has been removed because it was impossible

to do 32 bit emulation on 64-bit kernels with it.

These are all individually selectable via configuration options.

Much documentation for the interface is in the include files.  The

IPMI include files are:

net/af_ipmi.h - Contains the socket interface.

linux/ipmi.h - Contains the user interface and IOCTL interface for IPMI.

linux/ipmi_smi.h - Contains the interface for system management interfaces

and the user should not have to care what type of SMI is below them.

Watching For Interfaces

When your code comes up, the IPMI driver may or may not have detected

if IPMI devices exist.  So you might have to defer your setup until

the device is detected, or you might be able to do it immediately.

To handle this, and to allow for discovery, you register an SMI

watcher with ipmi_smi_watcher_register() to iterate over interfaces

and tell you when they come and go.

Creating the User

To user the message handler, you must first create a user using

Messaging

To send a message from kernel-land, the ipmi_request() call does

To send a message from kernel-land, the ipmi_request_settime() call does

pretty much all message handling.  Most of the parameter are

self-explanatory.  However, it takes a "msgid" parameter.  This is NOT

the sequence number of messages.  It is simply a long value that is

The SI Driver

-------------

The SI driver allows up to 4 KCS or SMIC interfaces to be configured

in the system.  By default, scan the ACPI tables for interfaces, and

if it doesn't find any the driver will attempt to register one KCS

interface at the spec-specified I/O port 0xca2 without interrupts.

You can change this at module load time (for a module) with:

The SI driver allows KCS, BT, and SMIC interfaces to be configured

in the system.  It discovers interfaces through a host of different

methods, depending on the system.

You can specify up to four interfaces on the module load line and

control some module parameters:

  modprobe ipmi_si.o type=<type1>,<type2>....

       ports=<port1>,<port2>... addrs=<addr1>,<addr2>...

       force_kipmid=<enable1>,<enable2>,...

       kipmid_max_busy_us=<ustime1>,<ustime2>,...

       unload_when_empty=[0|1]

       trydefaults=[0|1] trydmi=[0|1] tryacpi=[0|1]

       trydmi=[0|1] tryacpi=[0|1]

       tryplatform=[0|1] trypci=[0|1]

Each of these except try... items is a list, the first item for the

If you specify irqs as non-zero for an interface, the driver will

attempt to use the given interrupt for the device.

trydefaults sets whether the standard IPMI interface at 0xca2 and

any interfaces specified by ACPE are tried.  By default, the driver

tries it, set this value to zero to turn this off.

The other try... items disable discovery by their corresponding

names.  These are all enabled by default, set them to zero to disable

them.  The tryplatform disables openfirmware.

  ipmi_si.type=<type1>,<type2>...

       ipmi_si.ports=<port1>,<port2>... ipmi_si.addrs=<addr1>,<addr2>...

       ipmi_si.irqs=<irq1>,<irq2>... ipmi_si.trydefaults=[0|1]

       ipmi_si.irqs=<irq1>,<irq2>...

       ipmi_si.regspacings=<sp1>,<sp2>,...

       ipmi_si.regsizes=<size1>,<size2>,...

       ipmi_si.regshifts=<shift1>,<shift2>,...

It works the same as the module parameters of the same names.

By default, the driver will attempt to detect any device specified by

ACPI, and if none of those then a KCS device at the spec-specified

0xca2.  If you want to turn this off, set the "trydefaults" option to

false.

If your IPMI interface does not support interrupts and is a KCS or

SMIC interface, the IPMI driver will start a kernel thread for the

interface to help speed things up.  This is a low-priority kernel

	adapter=<adapter1>[,<adapter2>[...]]

	dbg=<flags1>,<flags2>...

	slave_addrs=<addr1>,<addr2>,...

	tryacpi=[0|1] trydmi=[0|1]

	[dbg_probe=1]

The addresses are normal I2C addresses.  The adapter is the string

The debug flags are bit flags for each BMC found, they are:

IPMI messages: 1, driver state: 2, timing: 4, I2C probe: 8

The tryxxx parameters can be used to disable detecting interfaces

from various sources.

Setting dbg_probe to 1 will enable debugging of the probing and

detection process for BMCs on the SMBusses.

	ipmi_ssif.dbg=<flags1>[,<flags2>[...]]

	ipmi_ssif.dbg_probe=1

	ipmi_ssif.slave_addrs=<addr1>[,<addr2>[...]]

	ipmi_ssif.tryacpi=[0|1] ipmi_ssif.trydmi=[0|1]

These are the same options as on the module command line.