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authorLinus Torvalds <torvalds@linux-foundation.org>2009-06-15 09:40:05 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-15 09:40:05 -0700
commit2ed0e21b30b53d3a94e204196e523e6c8f732b56 (patch)
treede2635426477d86338a9469ce09ba0626052288f /Documentation
parent0fa213310cd8fa7a51071cdcf130e26fa56e9549 (diff)
parent9cbc1cb8cd46ce1f7645b9de249b2ce8460129bb (diff)
downloadblackbird-op-linux-2ed0e21b30b53d3a94e204196e523e6c8f732b56.tar.gz
blackbird-op-linux-2ed0e21b30b53d3a94e204196e523e6c8f732b56.zip
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1244 commits) pkt_sched: Rename PSCHED_US2NS and PSCHED_NS2US ipv4: Fix fib_trie rebalancing Bluetooth: Fix issue with uninitialized nsh.type in DTL-1 driver Bluetooth: Fix Kconfig issue with RFKILL integration PIM-SM: namespace changes ipv4: update ARPD help text net: use a deferred timer in rt_check_expire ieee802154: fix kconfig bool/tristate muckup bonding: initialization rework bonding: use is_zero_ether_addr bonding: network device names are case sensative bonding: elminate bad refcount code bonding: fix style issues bonding: fix destructor bonding: remove bonding read/write semaphore bonding: initialize before registration bonding: bond_create always called with default parameters x_tables: Convert printk to pr_err netfilter: conntrack: optional reliable conntrack event delivery list_nulls: add hlist_nulls_add_head and hlist_nulls_del ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/DocBook/mac80211.tmpl1
-rw-r--r--Documentation/feature-removal-schedule.txt7
-rw-r--r--Documentation/isdn/00-INDEX29
-rw-r--r--Documentation/isdn/INTERFACE.CAPI94
-rw-r--r--Documentation/isdn/README.gigaset42
-rw-r--r--Documentation/networking/can.txt235
-rw-r--r--Documentation/networking/ieee802154.txt76
-rw-r--r--Documentation/networking/ip-sysctl.txt18
-rw-r--r--Documentation/networking/ipv6.txt37
-rw-r--r--Documentation/networking/mac80211-injection.txt28
-rw-r--r--Documentation/networking/operstates.txt3
-rw-r--r--Documentation/networking/packet_mmap.txt140
-rw-r--r--Documentation/powerpc/dts-bindings/can/sja1000.txt53
-rw-r--r--Documentation/rfkill.txt607
14 files changed, 729 insertions, 641 deletions
diff --git a/Documentation/DocBook/mac80211.tmpl b/Documentation/DocBook/mac80211.tmpl
index fbeaffc1dcc3..e36986663570 100644
--- a/Documentation/DocBook/mac80211.tmpl
+++ b/Documentation/DocBook/mac80211.tmpl
@@ -145,7 +145,6 @@ usage should require reading the full document.
interface in STA mode at first!
</para>
!Finclude/net/mac80211.h ieee80211_if_init_conf
-!Finclude/net/mac80211.h ieee80211_if_conf
</chapter>
<chapter id="rx-tx">
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index ec9ef5d0d7b3..7129846a2785 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -438,6 +438,13 @@ Why: Superseded by tdfxfb. I2C/DDC support used to live in a separate
Who: Jean Delvare <khali@linux-fr.org>
Krzysztof Helt <krzysztof.h1@wp.pl>
+---------------------------
+
+What: CONFIG_RFKILL_INPUT
+When: 2.6.33
+Why: Should be implemented in userspace, policy daemon.
+Who: Johannes Berg <johannes@sipsolutions.net>
+
----------------------------
What: CONFIG_X86_OLD_MCE
diff --git a/Documentation/isdn/00-INDEX b/Documentation/isdn/00-INDEX
index 5a2d69989a8c..f6010a536590 100644
--- a/Documentation/isdn/00-INDEX
+++ b/Documentation/isdn/00-INDEX
@@ -22,16 +22,11 @@ README.gigaset
- info on the drivers for Siemens Gigaset ISDN adapters.
README.icn
- info on the ICN-ISDN-card and its driver.
+>>>>>>> 93af7aca44f0e82e67bda10a0fb73d383edcc8bd:Documentation/isdn/00-INDEX
README.HiSax
- info on the HiSax driver which replaces the old teles.
-README.hfc-pci
- - info on hfc-pci based cards.
-README.pcbit
- - info on the PCBIT-D ISDN adapter and driver.
-README.syncppp
- - info on running Sync PPP over ISDN.
-syncPPP.FAQ
- - frequently asked questions about running PPP over ISDN.
+README.audio
+ - info for running audio over ISDN.
README.avmb1
- info on driver for AVM-B1 ISDN card.
README.act2000
@@ -42,10 +37,28 @@ README.concap
- info on "CONCAP" encapsulation protocol interface used for X.25.
README.diversion
- info on module for isdn diversion services.
+README.fax
+ - info for using Fax over ISDN.
+README.gigaset
+ - info on the drivers for Siemens Gigaset ISDN adapters
+README.hfc-pci
+ - info on hfc-pci based cards.
+README.hysdn
+ - info on driver for Hypercope active HYSDN cards
+README.icn
+ - info on the ICN-ISDN-card and its driver.
+README.mISDN
+ - info on the Modular ISDN subsystem (mISDN)
+README.pcbit
+ - info on the PCBIT-D ISDN adapter and driver.
README.sc
- info on driver for Spellcaster cards.
+README.syncppp
+ - info on running Sync PPP over ISDN.
README.x25
- info for running X.25 over ISDN.
+syncPPP.FAQ
+ - frequently asked questions about running PPP over ISDN.
README.hysdn
- info on driver for Hypercope active HYSDN cards
README.mISDN
diff --git a/Documentation/isdn/INTERFACE.CAPI b/Documentation/isdn/INTERFACE.CAPI
index 786d619b36e5..686e107923ec 100644
--- a/Documentation/isdn/INTERFACE.CAPI
+++ b/Documentation/isdn/INTERFACE.CAPI
@@ -45,7 +45,7 @@ From then on, Kernel CAPI may call the registered callback functions for the
device.
If the device becomes unusable for any reason (shutdown, disconnect ...), the
-driver has to call capi_ctr_reseted(). This will prevent further calls to the
+driver has to call capi_ctr_down(). This will prevent further calls to the
callback functions by Kernel CAPI.
@@ -114,20 +114,36 @@ char *driver_name
int (*load_firmware)(struct capi_ctr *ctrlr, capiloaddata *ldata)
(optional) pointer to a callback function for sending firmware and
configuration data to the device
+ Return value: 0 on success, error code on error
+ Called in process context.
void (*reset_ctr)(struct capi_ctr *ctrlr)
- pointer to a callback function for performing a reset on the device,
- releasing all registered applications
+ (optional) pointer to a callback function for performing a reset on
+ the device, releasing all registered applications
+ Called in process context.
void (*register_appl)(struct capi_ctr *ctrlr, u16 applid,
capi_register_params *rparam)
void (*release_appl)(struct capi_ctr *ctrlr, u16 applid)
pointers to callback functions for registration and deregistration of
applications with the device
+ Calls to these functions are serialized by Kernel CAPI so that only
+ one call to any of them is active at any time.
u16 (*send_message)(struct capi_ctr *ctrlr, struct sk_buff *skb)
pointer to a callback function for sending a CAPI message to the
device
+ Return value: CAPI error code
+ If the method returns 0 (CAPI_NOERROR) the driver has taken ownership
+ of the skb and the caller may no longer access it. If it returns a
+ non-zero (error) value then ownership of the skb returns to the caller
+ who may reuse or free it.
+ The return value should only be used to signal problems with respect
+ to accepting or queueing the message. Errors occurring during the
+ actual processing of the message should be signaled with an
+ appropriate reply message.
+ Calls to this function are not serialized by Kernel CAPI, ie. it must
+ be prepared to be re-entered.
char *(*procinfo)(struct capi_ctr *ctrlr)
pointer to a callback function returning the entry for the device in
@@ -138,6 +154,8 @@ read_proc_t *ctr_read_proc
system entry, /proc/capi/controllers/<n>; will be called with a
pointer to the device's capi_ctr structure as the last (data) argument
+Note: Callback functions are never called in interrupt context.
+
- to be filled in before calling capi_ctr_ready():
u8 manu[CAPI_MANUFACTURER_LEN]
@@ -153,6 +171,45 @@ u8 serial[CAPI_SERIAL_LEN]
value to return for CAPI_GET_SERIAL
+4.3 The _cmsg Structure
+
+(declared in <linux/isdn/capiutil.h>)
+
+The _cmsg structure stores the contents of a CAPI 2.0 message in an easily
+accessible form. It contains members for all possible CAPI 2.0 parameters, of
+which only those appearing in the message type currently being processed are
+actually used. Unused members should be set to zero.
+
+Members are named after the CAPI 2.0 standard names of the parameters they
+represent. See <linux/isdn/capiutil.h> for the exact spelling. Member data
+types are:
+
+u8 for CAPI parameters of type 'byte'
+
+u16 for CAPI parameters of type 'word'
+
+u32 for CAPI parameters of type 'dword'
+
+_cstruct for CAPI parameters of type 'struct' not containing any
+ variably-sized (struct) subparameters (eg. 'Called Party Number')
+ The member is a pointer to a buffer containing the parameter in
+ CAPI encoding (length + content). It may also be NULL, which will
+ be taken to represent an empty (zero length) parameter.
+
+_cmstruct for CAPI parameters of type 'struct' containing 'struct'
+ subparameters ('Additional Info' and 'B Protocol')
+ The representation is a single byte containing one of the values:
+ CAPI_DEFAULT: the parameter is empty
+ CAPI_COMPOSE: the values of the subparameters are stored
+ individually in the corresponding _cmsg structure members
+
+Functions capi_cmsg2message() and capi_message2cmsg() are provided to convert
+messages between their transport encoding described in the CAPI 2.0 standard
+and their _cmsg structure representation. Note that capi_cmsg2message() does
+not know or check the size of its destination buffer. The caller must make
+sure it is big enough to accomodate the resulting CAPI message.
+
+
5. Lower Layer Interface Functions
(declared in <linux/isdn/capilli.h>)
@@ -166,7 +223,7 @@ int detach_capi_ctr(struct capi_ctr *ctrlr)
register/unregister a device (controller) with Kernel CAPI
void capi_ctr_ready(struct capi_ctr *ctrlr)
-void capi_ctr_reseted(struct capi_ctr *ctrlr)
+void capi_ctr_down(struct capi_ctr *ctrlr)
signal controller ready/not ready
void capi_ctr_suspend_output(struct capi_ctr *ctrlr)
@@ -211,3 +268,32 @@ CAPIMSG_CONTROL(m) CAPIMSG_SETCONTROL(m, contr) Controller/PLCI/NCCI
(u32)
CAPIMSG_DATALEN(m) CAPIMSG_SETDATALEN(m, len) Data Length (u16)
+
+Library functions for working with _cmsg structures
+(from <linux/isdn/capiutil.h>):
+
+unsigned capi_cmsg2message(_cmsg *cmsg, u8 *msg)
+ Assembles a CAPI 2.0 message from the parameters in *cmsg, storing the
+ result in *msg.
+
+unsigned capi_message2cmsg(_cmsg *cmsg, u8 *msg)
+ Disassembles the CAPI 2.0 message in *msg, storing the parameters in
+ *cmsg.
+
+unsigned capi_cmsg_header(_cmsg *cmsg, u16 ApplId, u8 Command, u8 Subcommand,
+ u16 Messagenumber, u32 Controller)
+ Fills the header part and address field of the _cmsg structure *cmsg
+ with the given values, zeroing the remainder of the structure so only
+ parameters with non-default values need to be changed before sending
+ the message.
+
+void capi_cmsg_answer(_cmsg *cmsg)
+ Sets the low bit of the Subcommand field in *cmsg, thereby converting
+ _REQ to _CONF and _IND to _RESP.
+
+char *capi_cmd2str(u8 Command, u8 Subcommand)
+ Returns the CAPI 2.0 message name corresponding to the given command
+ and subcommand values, as a static ASCII string. The return value may
+ be NULL if the command/subcommand is not one of those defined in the
+ CAPI 2.0 standard.
+
diff --git a/Documentation/isdn/README.gigaset b/Documentation/isdn/README.gigaset
index 02c0e9341dd8..f9963103ae3d 100644
--- a/Documentation/isdn/README.gigaset
+++ b/Documentation/isdn/README.gigaset
@@ -149,10 +149,8 @@ GigaSet 307x Device Driver
configuration files and chat scripts in the gigaset-VERSION/ppp directory
in the driver packages from http://sourceforge.net/projects/gigaset307x/.
Please note that the USB drivers are not able to change the state of the
- control lines (the M105 driver can be configured to use some undocumented
- control requests, if you really need the control lines, though). This means
- you must use "Stupid Mode" if you are using wvdial or you should use the
- nocrtscts option of pppd.
+ control lines. This means you must use "Stupid Mode" if you are using
+ wvdial or you should use the nocrtscts option of pppd.
You must also assure that the ppp_async module is loaded with the parameter
flag_time=0. You can do this e.g. by adding a line like
@@ -190,20 +188,19 @@ GigaSet 307x Device Driver
You can also use /sys/class/tty/ttyGxy/cidmode for changing the CID mode
setting (ttyGxy is ttyGU0 or ttyGB0).
-2.6. M105 Undocumented USB Requests
- ------------------------------
-
- The Gigaset M105 USB data box understands a couple of useful, but
- undocumented USB commands. These requests are not used in normal
- operation (for wireless access to the base), but are needed for access
- to the M105's own configuration mode (registration to the base, baudrate
- and line format settings, device status queries) via the gigacontr
- utility. Their use is controlled by the kernel configuration option
- "Support for undocumented USB requests" (CONFIG_GIGASET_UNDOCREQ). If you
- encounter error code -ENOTTY when trying to use some features of the
- M105, try setting that option to "y" via 'make {x,menu}config' and
- recompiling the driver.
-
+2.6. Unregistered Wireless Devices (M101/M105)
+ -----------------------------------------
+ The main purpose of the ser_gigaset and usb_gigaset drivers is to allow
+ the M101 and M105 wireless devices to be used as ISDN devices for ISDN
+ connections through a Gigaset base. Therefore they assume that the device
+ is registered to a DECT base.
+
+ If the M101/M105 device is not registered to a base, initialization of
+ the device fails, and a corresponding error message is logged by the
+ driver. In that situation, a restricted set of functions is available
+ which includes, in particular, those necessary for registering the device
+ to a base or for switching it between Fixed Part and Portable Part
+ modes.
3. Troubleshooting
---------------
@@ -234,11 +231,12 @@ GigaSet 307x Device Driver
Select Unimodem mode for all DECT data adapters. (see section 2.4.)
Problem:
- You want to configure your USB DECT data adapter (M105) but gigacontr
- reports an error: "/dev/ttyGU0: Inappropriate ioctl for device".
+ Messages like this:
+ usb_gigaset 3-2:1.0: Could not initialize the device.
+ appear in your syslog.
Solution:
- Recompile the usb_gigaset driver with the kernel configuration option
- CONFIG_GIGASET_UNDOCREQ set to 'y'. (see section 2.6.)
+ Check whether your M10x wireless device is correctly registered to the
+ Gigaset base. (see section 2.6.)
3.2. Telling the driver to provide more information
----------------------------------------------
diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt
index 463d9e029ef3..cd79735013f9 100644
--- a/Documentation/networking/can.txt
+++ b/Documentation/networking/can.txt
@@ -36,10 +36,15 @@ This file contains
6.2 local loopback of sent frames
6.3 CAN controller hardware filters
6.4 The virtual CAN driver (vcan)
- 6.5 currently supported CAN hardware
- 6.6 todo
+ 6.5 The CAN network device driver interface
+ 6.5.1 Netlink interface to set/get devices properties
+ 6.5.2 Setting the CAN bit-timing
+ 6.5.3 Starting and stopping the CAN network device
+ 6.6 supported CAN hardware
- 7 Credits
+ 7 Socket CAN resources
+
+ 8 Credits
============================================================================
@@ -234,6 +239,8 @@ solution for a couple of reasons:
the user application using the common CAN filter mechanisms. Inside
this filter definition the (interested) type of errors may be
selected. The reception of error frames is disabled by default.
+ The format of the CAN error frame is briefly decribed in the Linux
+ header file "include/linux/can/error.h".
4. How to use Socket CAN
------------------------
@@ -605,61 +612,213 @@ solution for a couple of reasons:
removal of vcan network devices can be managed with the ip(8) tool:
- Create a virtual CAN network interface:
- ip link add type vcan
+ $ ip link add type vcan
- Create a virtual CAN network interface with a specific name 'vcan42':
- ip link add dev vcan42 type vcan
+ $ ip link add dev vcan42 type vcan
- Remove a (virtual CAN) network interface 'vcan42':
- ip link del vcan42
-
- The tool 'vcan' from the SocketCAN SVN repository on BerliOS is obsolete.
-
- Virtual CAN network device creation in older Kernels:
- In Linux Kernel versions < 2.6.24 the vcan driver creates 4 vcan
- netdevices at module load time by default. This value can be changed
- with the module parameter 'numdev'. E.g. 'modprobe vcan numdev=8'
-
- 6.5 currently supported CAN hardware
+ $ ip link del vcan42
+
+ 6.5 The CAN network device driver interface
+
+ The CAN network device driver interface provides a generic interface
+ to setup, configure and monitor CAN network devices. The user can then
+ configure the CAN device, like setting the bit-timing parameters, via
+ the netlink interface using the program "ip" from the "IPROUTE2"
+ utility suite. The following chapter describes briefly how to use it.
+ Furthermore, the interface uses a common data structure and exports a
+ set of common functions, which all real CAN network device drivers
+ should use. Please have a look to the SJA1000 or MSCAN driver to
+ understand how to use them. The name of the module is can-dev.ko.
+
+ 6.5.1 Netlink interface to set/get devices properties
+
+ The CAN device must be configured via netlink interface. The supported
+ netlink message types are defined and briefly described in
+ "include/linux/can/netlink.h". CAN link support for the program "ip"
+ of the IPROUTE2 utility suite is avaiable and it can be used as shown
+ below:
+
+ - Setting CAN device properties:
+
+ $ ip link set can0 type can help
+ Usage: ip link set DEVICE type can
+ [ bitrate BITRATE [ sample-point SAMPLE-POINT] ] |
+ [ tq TQ prop-seg PROP_SEG phase-seg1 PHASE-SEG1
+ phase-seg2 PHASE-SEG2 [ sjw SJW ] ]
+
+ [ loopback { on | off } ]
+ [ listen-only { on | off } ]
+ [ triple-sampling { on | off } ]
+
+ [ restart-ms TIME-MS ]
+ [ restart ]
+
+ Where: BITRATE := { 1..1000000 }
+ SAMPLE-POINT := { 0.000..0.999 }
+ TQ := { NUMBER }
+ PROP-SEG := { 1..8 }
+ PHASE-SEG1 := { 1..8 }
+ PHASE-SEG2 := { 1..8 }
+ SJW := { 1..4 }
+ RESTART-MS := { 0 | NUMBER }
+
+ - Display CAN device details and statistics:
+
+ $ ip -details -statistics link show can0
+ 2: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UP qlen 10
+ link/can
+ can <TRIPLE-SAMPLING> state ERROR-ACTIVE restart-ms 100
+ bitrate 125000 sample_point 0.875
+ tq 125 prop-seg 6 phase-seg1 7 phase-seg2 2 sjw 1
+ sja1000: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1
+ clock 8000000
+ re-started bus-errors arbit-lost error-warn error-pass bus-off
+ 41 17457 0 41 42 41
+ RX: bytes packets errors dropped overrun mcast
+ 140859 17608 17457 0 0 0
+ TX: bytes packets errors dropped carrier collsns
+ 861 112 0 41 0 0
+
+ More info to the above output:
+
+ "<TRIPLE-SAMPLING>"
+ Shows the list of selected CAN controller modes: LOOPBACK,
+ LISTEN-ONLY, or TRIPLE-SAMPLING.
+
+ "state ERROR-ACTIVE"
+ The current state of the CAN controller: "ERROR-ACTIVE",
+ "ERROR-WARNING", "ERROR-PASSIVE", "BUS-OFF" or "STOPPED"
+
+ "restart-ms 100"
+ Automatic restart delay time. If set to a non-zero value, a
+ restart of the CAN controller will be triggered automatically
+ in case of a bus-off condition after the specified delay time
+ in milliseconds. By default it's off.
+
+ "bitrate 125000 sample_point 0.875"
+ Shows the real bit-rate in bits/sec and the sample-point in the
+ range 0.000..0.999. If the calculation of bit-timing parameters
+ is enabled in the kernel (CONFIG_CAN_CALC_BITTIMING=y), the
+ bit-timing can be defined by setting the "bitrate" argument.
+ Optionally the "sample-point" can be specified. By default it's
+ 0.000 assuming CIA-recommended sample-points.
+
+ "tq 125 prop-seg 6 phase-seg1 7 phase-seg2 2 sjw 1"
+ Shows the time quanta in ns, propagation segment, phase buffer
+ segment 1 and 2 and the synchronisation jump width in units of
+ tq. They allow to define the CAN bit-timing in a hardware
+ independent format as proposed by the Bosch CAN 2.0 spec (see
+ chapter 8 of http://www.semiconductors.bosch.de/pdf/can2spec.pdf).
+
+ "sja1000: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1
+ clock 8000000"
+ Shows the bit-timing constants of the CAN controller, here the
+ "sja1000". The minimum and maximum values of the time segment 1
+ and 2, the synchronisation jump width in units of tq, the
+ bitrate pre-scaler and the CAN system clock frequency in Hz.
+ These constants could be used for user-defined (non-standard)
+ bit-timing calculation algorithms in user-space.
+
+ "re-started bus-errors arbit-lost error-warn error-pass bus-off"
+ Shows the number of restarts, bus and arbitration lost errors,
+ and the state changes to the error-warning, error-passive and
+ bus-off state. RX overrun errors are listed in the "overrun"
+ field of the standard network statistics.
+
+ 6.5.2 Setting the CAN bit-timing
+
+ The CAN bit-timing parameters can always be defined in a hardware
+ independent format as proposed in the Bosch CAN 2.0 specification
+ specifying the arguments "tq", "prop_seg", "phase_seg1", "phase_seg2"
+ and "sjw":
+
+ $ ip link set canX type can tq 125 prop-seg 6 \
+ phase-seg1 7 phase-seg2 2 sjw 1
+
+ If the kernel option CONFIG_CAN_CALC_BITTIMING is enabled, CIA
+ recommended CAN bit-timing parameters will be calculated if the bit-
+ rate is specified with the argument "bitrate":
+
+ $ ip link set canX type can bitrate 125000
+
+ Note that this works fine for the most common CAN controllers with
+ standard bit-rates but may *fail* for exotic bit-rates or CAN system
+ clock frequencies. Disabling CONFIG_CAN_CALC_BITTIMING saves some
+ space and allows user-space tools to solely determine and set the
+ bit-timing parameters. The CAN controller specific bit-timing
+ constants can be used for that purpose. They are listed by the
+ following command:
+
+ $ ip -details link show can0
+ ...
+ sja1000: clock 8000000 tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1
+
+ 6.5.3 Starting and stopping the CAN network device
+
+ A CAN network device is started or stopped as usual with the command
+ "ifconfig canX up/down" or "ip link set canX up/down". Be aware that
+ you *must* define proper bit-timing parameters for real CAN devices
+ before you can start it to avoid error-prone default settings:
+
+ $ ip link set canX up type can bitrate 125000
+
+ A device may enter the "bus-off" state if too much errors occurred on
+ the CAN bus. Then no more messages are received or sent. An automatic
+ bus-off recovery can be enabled by setting the "restart-ms" to a
+ non-zero value, e.g.:
+
+ $ ip link set canX type can restart-ms 100
+
+ Alternatively, the application may realize the "bus-off" condition
+ by monitoring CAN error frames and do a restart when appropriate with
+ the command:
+
+ $ ip link set canX type can restart
+
+ Note that a restart will also create a CAN error frame (see also
+ chapter 3.4).
- On the project website http://developer.berlios.de/projects/socketcan
- there are different drivers available:
+ 6.6 Supported CAN hardware
- vcan: Virtual CAN interface driver (if no real hardware is available)
- sja1000: Philips SJA1000 CAN controller (recommended)
- i82527: Intel i82527 CAN controller
- mscan: Motorola/Freescale CAN controller (e.g. inside SOC MPC5200)
- ccan: CCAN controller core (e.g. inside SOC h7202)
- slcan: For a bunch of CAN adaptors that are attached via a
- serial line ASCII protocol (for serial / USB adaptors)
+ Please check the "Kconfig" file in "drivers/net/can" to get an actual
+ list of the support CAN hardware. On the Socket CAN project website
+ (see chapter 7) there might be further drivers available, also for
+ older kernel versions.
- Additionally the different CAN adaptors (ISA/PCI/PCMCIA/USB/Parport)
- from PEAK Systemtechnik support the CAN netdevice driver model
- since Linux driver v6.0: http://www.peak-system.com/linux/index.htm
+7. Socket CAN resources
+-----------------------
- Please check the Mailing Lists on the berlios OSS project website.
+ You can find further resources for Socket CAN like user space tools,
+ support for old kernel versions, more drivers, mailing lists, etc.
+ at the BerliOS OSS project website for Socket CAN:
- 6.6 todo
+ http://developer.berlios.de/projects/socketcan
- The configuration interface for CAN network drivers is still an open
- issue that has not been finalized in the socketcan project. Also the
- idea of having a library module (candev.ko) that holds functions
- that are needed by all CAN netdevices is not ready to ship.
- Your contribution is welcome.
+ If you have questions, bug fixes, etc., don't hesitate to post them to
+ the Socketcan-Users mailing list. But please search the archives first.
-7. Credits
+8. Credits
----------
- Oliver Hartkopp (PF_CAN core, filters, drivers, bcm)
+ Oliver Hartkopp (PF_CAN core, filters, drivers, bcm, SJA1000 driver)
Urs Thuermann (PF_CAN core, kernel integration, socket interfaces, raw, vcan)
Jan Kizka (RT-SocketCAN core, Socket-API reconciliation)
- Wolfgang Grandegger (RT-SocketCAN core & drivers, Raw Socket-API reviews)
+ Wolfgang Grandegger (RT-SocketCAN core & drivers, Raw Socket-API reviews,
+ CAN device driver interface, MSCAN driver)
Robert Schwebel (design reviews, PTXdist integration)
Marc Kleine-Budde (design reviews, Kernel 2.6 cleanups, drivers)
Benedikt Spranger (reviews)
Thomas Gleixner (LKML reviews, coding style, posting hints)
- Andrey Volkov (kernel subtree structure, ioctls, mscan driver)
+ Andrey Volkov (kernel subtree structure, ioctls, MSCAN driver)
Matthias Brukner (first SJA1000 CAN netdevice implementation Q2/2003)
Klaus Hitschler (PEAK driver integration)
Uwe Koppe (CAN netdevices with PF_PACKET approach)
Michael Schulze (driver layer loopback requirement, RT CAN drivers review)
+ Pavel Pisa (Bit-timing calculation)
+ Sascha Hauer (SJA1000 platform driver)
+ Sebastian Haas (SJA1000 EMS PCI driver)
+ Markus Plessing (SJA1000 EMS PCI driver)
+ Per Dalen (SJA1000 Kvaser PCI driver)
+ Sam Ravnborg (reviews, coding style, kbuild help)
diff --git a/Documentation/networking/ieee802154.txt b/Documentation/networking/ieee802154.txt
new file mode 100644
index 000000000000..a0280ad2edc9
--- /dev/null
+++ b/Documentation/networking/ieee802154.txt
@@ -0,0 +1,76 @@
+
+ Linux IEEE 802.15.4 implementation
+
+
+Introduction
+============
+
+The Linux-ZigBee project goal is to provide complete implementation
+of IEEE 802.15.4 / ZigBee / 6LoWPAN protocols. IEEE 802.15.4 is a stack
+of protocols for organizing Low-Rate Wireless Personal Area Networks.
+
+Currently only IEEE 802.15.4 layer is implemented. We have choosen
+to use plain Berkeley socket API, the generic Linux networking stack
+to transfer IEEE 802.15.4 messages and a special protocol over genetlink
+for configuration/management
+
+
+Socket API
+==========
+
+int sd = socket(PF_IEEE802154, SOCK_DGRAM, 0);
+.....
+
+The address family, socket addresses etc. are defined in the
+include/net/ieee802154/af_ieee802154.h header or in the special header
+in our userspace package (see either linux-zigbee sourceforge download page
+or git tree at git://linux-zigbee.git.sourceforge.net/gitroot/linux-zigbee).
+
+One can use SOCK_RAW for passing raw data towards device xmit function. YMMV.
+
+
+MLME - MAC Level Management
+============================
+
+Most of IEEE 802.15.4 MLME interfaces are directly mapped on netlink commands.
+See the include/net/ieee802154/nl802154.h header. Our userspace tools package
+(see above) provides CLI configuration utility for radio interfaces and simple
+coordinator for IEEE 802.15.4 networks as an example users of MLME protocol.
+
+
+Kernel side
+=============
+
+Like with WiFi, there are several types of devices implementing IEEE 802.15.4.
+1) 'HardMAC'. The MAC layer is implemented in the device itself, the device
+ exports MLME and data API.
+2) 'SoftMAC' or just radio. These types of devices are just radio transceivers
+ possibly with some kinds of acceleration like automatic CRC computation and
+ comparation, automagic ACK handling, address matching, etc.
+
+Those types of devices require different approach to be hooked into Linux kernel.
+
+
+HardMAC
+=======
+
+See the header include/net/ieee802154/netdevice.h. You have to implement Linux
+net_device, with .type = ARPHRD_IEEE802154. Data is exchanged with socket family
+code via plain sk_buffs. The control block of sk_buffs will contain additional
+info as described in the struct ieee802154_mac_cb.
+
+To hook the MLME interface you have to populate the ml_priv field of your
+net_device with a pointer to struct ieee802154_mlme_ops instance. All fields are
+required.
+
+We provide an example of simple HardMAC driver at drivers/ieee802154/fakehard.c
+
+
+SoftMAC
+=======
+
+We are going to provide intermediate layer impelementing IEEE 802.15.4 MAC
+in software. This is currently WIP.
+
+See header include/net/ieee802154/mac802154.h and several drivers in
+drivers/ieee802154/
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index b121c5db707f..8be76235fe67 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -168,7 +168,16 @@ tcp_dsack - BOOLEAN
Allows TCP to send "duplicate" SACKs.
tcp_ecn - BOOLEAN
- Enable Explicit Congestion Notification in TCP.
+ Enable Explicit Congestion Notification (ECN) in TCP. ECN is only
+ used when both ends of the TCP flow support it. It is useful to
+ avoid losses due to congestion (when the bottleneck router supports
+ ECN).
+ Possible values are:
+ 0 disable ECN
+ 1 ECN enabled
+ 2 Only server-side ECN enabled. If the other end does
+ not support ECN, behavior is like with ECN disabled.
+ Default: 2
tcp_fack - BOOLEAN
Enable FACK congestion avoidance and fast retransmission.
@@ -1048,6 +1057,13 @@ disable_ipv6 - BOOLEAN
address.
Default: FALSE (enable IPv6 operation)
+ When this value is changed from 1 to 0 (IPv6 is being enabled),
+ it will dynamically create a link-local address on the given
+ interface and start Duplicate Address Detection, if necessary.
+
+ When this value is changed from 0 to 1 (IPv6 is being disabled),
+ it will dynamically delete all address on the given interface.
+
accept_dad - INTEGER
Whether to accept DAD (Duplicate Address Detection).
0: Disable DAD
diff --git a/Documentation/networking/ipv6.txt b/Documentation/networking/ipv6.txt
index 268e5c103dd8..9fd7e21296c8 100644
--- a/Documentation/networking/ipv6.txt
+++ b/Documentation/networking/ipv6.txt
@@ -33,3 +33,40 @@ disable
A reboot is required to enable IPv6.
+autoconf
+
+ Specifies whether to enable IPv6 address autoconfiguration
+ on all interfaces. This might be used when one does not wish
+ for addresses to be automatically generated from prefixes
+ received in Router Advertisements.
+
+ The possible values and their effects are:
+
+ 0
+ IPv6 address autoconfiguration is disabled on all interfaces.
+
+ Only the IPv6 loopback address (::1) and link-local addresses
+ will be added to interfaces.
+
+ 1
+ IPv6 address autoconfiguration is enabled on all interfaces.
+
+ This is the default value.
+
+disable_ipv6
+
+ Specifies whether to disable IPv6 on all interfaces.
+ This might be used when no IPv6 addresses are desired.
+
+ The possible values and their effects are:
+
+ 0
+ IPv6 is enabled on all interfaces.
+
+ This is the default value.
+
+ 1
+ IPv6 is disabled on all interfaces.
+
+ No IPv6 addresses will be added to interfaces.
+
diff --git a/Documentation/networking/mac80211-injection.txt b/Documentation/networking/mac80211-injection.txt
index 84906ef3ed6e..b30e81ad5307 100644
--- a/Documentation/networking/mac80211-injection.txt
+++ b/Documentation/networking/mac80211-injection.txt
@@ -12,38 +12,22 @@ following format:
The radiotap format is discussed in
./Documentation/networking/radiotap-headers.txt.
-Despite 13 radiotap argument types are currently defined, most only make sense
+Despite many radiotap parameters being currently defined, most only make sense
to appear on received packets. The following information is parsed from the
radiotap headers and used to control injection:
- * IEEE80211_RADIOTAP_RATE
-
- rate in 500kbps units, automatic if invalid or not present
-
-
- * IEEE80211_RADIOTAP_ANTENNA
-
- antenna to use, automatic if not present
-
-
- * IEEE80211_RADIOTAP_DBM_TX_POWER
-
- transmit power in dBm, automatic if not present
-
-
* IEEE80211_RADIOTAP_FLAGS
IEEE80211_RADIOTAP_F_FCS: FCS will be removed and recalculated
IEEE80211_RADIOTAP_F_WEP: frame will be encrypted if key available
IEEE80211_RADIOTAP_F_FRAG: frame will be fragmented if longer than the
- current fragmentation threshold. Note that
- this flag is only reliable when software
- fragmentation is enabled)
+ current fragmentation threshold.
+
The injection code can also skip all other currently defined radiotap fields
facilitating replay of captured radiotap headers directly.
-Here is an example valid radiotap header defining these three parameters
+Here is an example valid radiotap header defining some parameters
0x00, 0x00, // <-- radiotap version
0x0b, 0x00, // <- radiotap header length
@@ -72,8 +56,8 @@ interface), along the following lines:
...
r = pcap_inject(ppcap, u8aSendBuffer, nLength);
-You can also find sources for a complete inject test applet here:
+You can also find a link to a complete inject application here:
-http://penumbra.warmcat.com/_twk/tiki-index.php?page=packetspammer
+http://wireless.kernel.org/en/users/Documentation/packetspammer
Andy Green <andy@warmcat.com>
diff --git a/Documentation/networking/operstates.txt b/Documentation/networking/operstates.txt
index c9074f9b78bb..1a77a3cfae54 100644
--- a/Documentation/networking/operstates.txt
+++ b/Documentation/networking/operstates.txt
@@ -38,9 +38,6 @@ ifinfomsg::if_flags & IFF_LOWER_UP:
ifinfomsg::if_flags & IFF_DORMANT:
Driver has signaled netif_dormant_on()
-These interface flags can also be queried without netlink using the
-SIOCGIFFLAGS ioctl.
-
TLV IFLA_OPERSTATE
contains RFC2863 state of the interface in numeric representation:
diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt
index 07c53d596035..a22fd85e3796 100644
--- a/Documentation/networking/packet_mmap.txt
+++ b/Documentation/networking/packet_mmap.txt
@@ -4,16 +4,18 @@
This file documents the CONFIG_PACKET_MMAP option available with the PACKET
socket interface on 2.4 and 2.6 kernels. This type of sockets is used for
-capture network traffic with utilities like tcpdump or any other that uses
-the libpcap library.
-
-You can find the latest version of this document at
+capture network traffic with utilities like tcpdump or any other that needs
+raw access to network interface.
+You can find the latest version of this document at:
http://pusa.uv.es/~ulisses/packet_mmap/
-Please send me your comments to
+Howto can be found at:
+ http://wiki.gnu-log.net (packet_mmap)
+Please send your comments to
Ulisses Alonso Camaró <uaca@i.hate.spam.alumni.uv.es>
+ Johann Baudy <johann.baudy@gnu-log.net>
-------------------------------------------------------------------------------
+ Why use PACKET_MMAP
@@ -25,19 +27,24 @@ to capture each packet, it requires two if you want to get packet's
timestamp (like libpcap always does).
In the other hand PACKET_MMAP is very efficient. PACKET_MMAP provides a size
-configurable circular buffer mapped in user space. This way reading packets just
-needs to wait for them, most of the time there is no need to issue a single
-system call. By using a shared buffer between the kernel and the user
-also has the benefit of minimizing packet copies.
-
-It's fine to use PACKET_MMAP to improve the performance of the capture process,
-but it isn't everything. At least, if you are capturing at high speeds (this
-is relative to the cpu speed), you should check if the device driver of your
-network interface card supports some sort of interrupt load mitigation or
-(even better) if it supports NAPI, also make sure it is enabled.
+configurable circular buffer mapped in user space that can be used to either
+send or receive packets. This way reading packets just needs to wait for them,
+most of the time there is no need to issue a single system call. Concerning
+transmission, multiple packets can be sent through one system call to get the
+highest bandwidth.
+By using a shared buffer between the kernel and the user also has the benefit
+of minimizing packet copies.
+
+It's fine to use PACKET_MMAP to improve the performance of the capture and
+transmission process, but it isn't everything. At least, if you are capturing
+at high speeds (this is relative to the cpu speed), you should check if the
+device driver of your network interface card supports some sort of interrupt
+load mitigation or (even better) if it supports NAPI, also make sure it is
+enabled. For transmission, check the MTU (Maximum Transmission Unit) used and
+supported by devices of your network.
--------------------------------------------------------------------------------
-+ How to use CONFIG_PACKET_MMAP
++ How to use CONFIG_PACKET_MMAP to improve capture process
--------------------------------------------------------------------------------
From the user standpoint, you should use the higher level libpcap library, which
@@ -57,7 +64,7 @@ the low level details or want to improve libpcap by including PACKET_MMAP
support.
--------------------------------------------------------------------------------
-+ How to use CONFIG_PACKET_MMAP directly
++ How to use CONFIG_PACKET_MMAP directly to improve capture process
--------------------------------------------------------------------------------
From the system calls stand point, the use of PACKET_MMAP involves
@@ -66,6 +73,7 @@ the following process:
[setup] socket() -------> creation of the capture socket
setsockopt() ---> allocation of the circular buffer (ring)
+ option: PACKET_RX_RING
mmap() ---------> mapping of the allocated buffer to the
user process
@@ -97,13 +105,75 @@ also the mapping of the circular buffer in the user process and
the use of this buffer.
--------------------------------------------------------------------------------
++ How to use CONFIG_PACKET_MMAP directly to improve transmission process
+--------------------------------------------------------------------------------
+Transmission process is similar to capture as shown below.
+
+[setup] socket() -------> creation of the transmission socket
+ setsockopt() ---> allocation of the circular buffer (ring)
+ option: PACKET_TX_RING
+ bind() ---------> bind transmission socket with a network interface
+ mmap() ---------> mapping of the allocated buffer to the
+ user process
+
+[transmission] poll() ---------> wait for free packets (optional)
+ send() ---------> send all packets that are set as ready in
+ the ring
+ The flag MSG_DONTWAIT can be used to return
+ before end of transfer.
+
+[shutdown] close() --------> destruction of the transmission socket and
+ deallocation of all associated resources.
+
+Binding the socket to your network interface is mandatory (with zero copy) to
+know the header size of frames used in the circular buffer.
+
+As capture, each frame contains two parts:
+
+ --------------------
+| struct tpacket_hdr | Header. It contains the status of
+| | of this frame
+|--------------------|
+| data buffer |
+. . Data that will be sent over the network interface.
+. .
+ --------------------
+
+ bind() associates the socket to your network interface thanks to
+ sll_ifindex parameter of struct sockaddr_ll.
+
+ Initialization example:
+
+ struct sockaddr_ll my_addr;
+ struct ifreq s_ifr;
+ ...
+
+ strncpy (s_ifr.ifr_name, "eth0", sizeof(s_ifr.ifr_name));
+
+ /* get interface index of eth0 */
+ ioctl(this->socket, SIOCGIFINDEX, &s_ifr);
+
+ /* fill sockaddr_ll struct to prepare binding */
+ my_addr.sll_family = AF_PACKET;
+ my_addr.sll_protocol = ETH_P_ALL;
+ my_addr.sll_ifindex = s_ifr.ifr_ifindex;
+
+ /* bind socket to eth0 */
+ bind(this->socket, (struct sockaddr *)&my_addr, sizeof(struct sockaddr_ll));
+
+ A complete tutorial is available at: http://wiki.gnu-log.net/
+
+--------------------------------------------------------------------------------
+ PACKET_MMAP settings
--------------------------------------------------------------------------------
To setup PACKET_MMAP from user level code is done with a call like
+ - Capture process
setsockopt(fd, SOL_PACKET, PACKET_RX_RING, (void *) &req, sizeof(req))
+ - Transmission process
+ setsockopt(fd, SOL_PACKET, PACKET_TX_RING, (void *) &req, sizeof(req))
The most significant argument in the previous call is the req parameter,
this parameter must to have the following structure:
@@ -117,11 +187,11 @@ this parameter must to have the following structure:
};
This structure is defined in /usr/include/linux/if_packet.h and establishes a
-circular buffer (ring) of unswappable memory mapped in the capture process.
+circular buffer (ring) of unswappable memory.
Being mapped in the capture process allows reading the captured frames and
related meta-information like timestamps without requiring a system call.
-Captured frames are grouped in blocks. Each block is a physically contiguous
+Frames are grouped in blocks. Each block is a physically contiguous
region of memory and holds tp_block_size/tp_frame_size frames. The total number
of blocks is tp_block_nr. Note that tp_frame_nr is a redundant parameter because
@@ -336,6 +406,7 @@ struct tpacket_hdr). If this field is 0 means that the frame is ready
to be used for the kernel, If not, there is a frame the user can read
and the following flags apply:
++++ Capture process:
from include/linux/if_packet.h
#define TP_STATUS_COPY 2
@@ -391,6 +462,37 @@ packets are in the ring:
It doesn't incur in a race condition to first check the status value and
then poll for frames.
+
+++ Transmission process
+Those defines are also used for transmission:
+
+ #define TP_STATUS_AVAILABLE 0 // Frame is available
+ #define TP_STATUS_SEND_REQUEST 1 // Frame will be sent on next send()
+ #define TP_STATUS_SENDING 2 // Frame is currently in transmission
+ #define TP_STATUS_WRONG_FORMAT 4 // Frame format is not correct
+
+First, the kernel initializes all frames to TP_STATUS_AVAILABLE. To send a
+packet, the user fills a data buffer of an available frame, sets tp_len to
+current data buffer size and sets its status field to TP_STATUS_SEND_REQUEST.
+This can be done on multiple frames. Once the user is ready to transmit, it
+calls send(). Then all buffers with status equal to TP_STATUS_SEND_REQUEST are
+forwarded to the network device. The kernel updates each status of sent
+frames with TP_STATUS_SENDING until the end of transfer.
+At the end of each transfer, buffer status returns to TP_STATUS_AVAILABLE.
+
+ header->tp_len = in_i_size;
+ header->tp_status = TP_STATUS_SEND_REQUEST;
+ retval = send(this->socket, NULL, 0, 0);
+
+The user can also use poll() to check if a buffer is available:
+(status == TP_STATUS_SENDING)
+
+ struct pollfd pfd;
+ pfd.fd = fd;
+ pfd.revents = 0;
+ pfd.events = POLLOUT;
+ retval = poll(&pfd, 1, timeout);
+
--------------------------------------------------------------------------------
+ THANKS
--------------------------------------------------------------------------------
diff --git a/Documentation/powerpc/dts-bindings/can/sja1000.txt b/Documentation/powerpc/dts-bindings/can/sja1000.txt
new file mode 100644
index 000000000000..d6d209ded937
--- /dev/null
+++ b/Documentation/powerpc/dts-bindings/can/sja1000.txt
@@ -0,0 +1,53 @@
+Memory mapped SJA1000 CAN controller from NXP (formerly Philips)
+
+Required properties:
+
+- compatible : should be "nxp,sja1000".
+
+- reg : should specify the chip select, address offset and size required
+ to map the registers of the SJA1000. The size is usually 0x80.
+
+- interrupts: property with a value describing the interrupt source
+ (number and sensitivity) required for the SJA1000.
+
+Optional properties:
+
+- nxp,external-clock-frequency : Frequency of the external oscillator
+ clock in Hz. Note that the internal clock frequency used by the
+ SJA1000 is half of that value. If not specified, a default value
+ of 16000000 (16 MHz) is used.
+
+- nxp,tx-output-mode : operation mode of the TX output control logic:
+ <0x0> : bi-phase output mode
+ <0x1> : normal output mode (default)
+ <0x2> : test output mode
+ <0x3> : clock output mode
+
+- nxp,tx-output-config : TX output pin configuration:
+ <0x01> : TX0 invert
+ <0x02> : TX0 pull-down (default)
+ <0x04> : TX0 pull-up
+ <0x06> : TX0 push-pull
+ <0x08> : TX1 invert
+ <0x10> : TX1 pull-down
+ <0x20> : TX1 pull-up
+ <0x30> : TX1 push-pull
+
+- nxp,clock-out-frequency : clock frequency in Hz on the CLKOUT pin.
+ If not specified or if the specified value is 0, the CLKOUT pin
+ will be disabled.
+
+- nxp,no-comparator-bypass : Allows to disable the CAN input comperator.
+
+For futher information, please have a look to the SJA1000 data sheet.
+
+Examples:
+
+can@3,100 {
+ compatible = "nxp,sja1000";
+ reg = <3 0x100 0x80>;
+ interrupts = <2 0>;
+ interrupt-parent = <&mpic>;
+ nxp,external-clock-frequency = <16000000>;
+};
+
diff --git a/Documentation/rfkill.txt b/Documentation/rfkill.txt
index 4d3ee317a4a3..1b74b5f30af4 100644
--- a/Documentation/rfkill.txt
+++ b/Documentation/rfkill.txt
@@ -1,575 +1,136 @@
-rfkill - RF switch subsystem support
-====================================
+rfkill - RF kill switch support
+===============================
-1 Introduction
-2 Implementation details
-3 Kernel driver guidelines
-3.1 wireless device drivers
-3.2 platform/switch drivers
-3.3 input device drivers
-4 Kernel API
-5 Userspace support
+1. Introduction
+2. Implementation details
+3. Kernel driver guidelines
+4. Kernel API
+5. Userspace support
-1. Introduction:
+1. Introduction
-The rfkill switch subsystem exists to add a generic interface to circuitry that
-can enable or disable the signal output of a wireless *transmitter* of any
-type. By far, the most common use is to disable radio-frequency transmitters.
+The rfkill subsystem provides a generic interface to disabling any radio
+transmitter in the system. When a transmitter is blocked, it shall not
+radiate any power.
-Note that disabling the signal output means that the the transmitter is to be
-made to not emit any energy when "blocked". rfkill is not about blocking data
-transmissions, it is about blocking energy emission.
+The subsystem also provides the ability to react on button presses and
+disable all transmitters of a certain type (or all). This is intended for
+situations where transmitters need to be turned off, for example on
+aircraft.
-The rfkill subsystem offers support for keys and switches often found on
-laptops to enable wireless devices like WiFi and Bluetooth, so that these keys
-and switches actually perform an action in all wireless devices of a given type
-attached to the system.
-The buttons to enable and disable the wireless transmitters are important in
-situations where the user is for example using his laptop on a location where
-radio-frequency transmitters _must_ be disabled (e.g. airplanes).
-Because of this requirement, userspace support for the keys should not be made
-mandatory. Because userspace might want to perform some additional smarter
-tasks when the key is pressed, rfkill provides userspace the possibility to
-take over the task to handle the key events.
-
-===============================================================================
-2: Implementation details
+2. Implementation details
The rfkill subsystem is composed of various components: the rfkill class, the
rfkill-input module (an input layer handler), and some specific input layer
events.
-The rfkill class provides kernel drivers with an interface that allows them to
-know when they should enable or disable a wireless network device transmitter.
-This is enabled by the CONFIG_RFKILL Kconfig option.
-
-The rfkill class support makes sure userspace will be notified of all state
-changes on rfkill devices through uevents. It provides a notification chain
-for interested parties in the kernel to also get notified of rfkill state
-changes in other drivers. It creates several sysfs entries which can be used
-by userspace. See section "Userspace support".
-
-The rfkill-input module provides the kernel with the ability to implement a
-basic response when the user presses a key or button (or toggles a switch)
-related to rfkill functionality. It is an in-kernel implementation of default
-policy of reacting to rfkill-related input events and neither mandatory nor
-required for wireless drivers to operate. It is enabled by the
-CONFIG_RFKILL_INPUT Kconfig option.
-
-rfkill-input is a rfkill-related events input layer handler. This handler will
-listen to all rfkill key events and will change the rfkill state of the
-wireless devices accordingly. With this option enabled userspace could either
-do nothing or simply perform monitoring tasks.
-
-The rfkill-input module also provides EPO (emergency power-off) functionality
-for all wireless transmitters. This function cannot be overridden, and it is
-always active. rfkill EPO is related to *_RFKILL_ALL input layer events.
-
-
-Important terms for the rfkill subsystem:
-
-In order to avoid confusion, we avoid the term "switch" in rfkill when it is
-referring to an electronic control circuit that enables or disables a
-transmitter. We reserve it for the physical device a human manipulates
-(which is an input device, by the way):
-
-rfkill switch:
-
- A physical device a human manipulates. Its state can be perceived by
- the kernel either directly (through a GPIO pin, ACPI GPE) or by its
- effect on a rfkill line of a wireless device.
-
-rfkill controller:
-
- A hardware circuit that controls the state of a rfkill line, which a
- kernel driver can interact with *to modify* that state (i.e. it has
- either write-only or read/write access).
-
-rfkill line:
-
- An input channel (hardware or software) of a wireless device, which
- causes a wireless transmitter to stop emitting energy (BLOCK) when it
- is active. Point of view is extremely important here: rfkill lines are
- always seen from the PoV of a wireless device (and its driver).
-
-soft rfkill line/software rfkill line:
-
- A rfkill line the wireless device driver can directly change the state
- of. Related to rfkill_state RFKILL_STATE_SOFT_BLOCKED.
-
-hard rfkill line/hardware rfkill line:
-
- A rfkill line that works fully in hardware or firmware, and that cannot
- be overridden by the kernel driver. The hardware device or the
- firmware just exports its status to the driver, but it is read-only.
- Related to rfkill_state RFKILL_STATE_HARD_BLOCKED.
-
-The enum rfkill_state describes the rfkill state of a transmitter:
-
-When a rfkill line or rfkill controller is in the RFKILL_STATE_UNBLOCKED state,
-the wireless transmitter (radio TX circuit for example) is *enabled*. When the
-it is in the RFKILL_STATE_SOFT_BLOCKED or RFKILL_STATE_HARD_BLOCKED, the
-wireless transmitter is to be *blocked* from operating.
-
-RFKILL_STATE_SOFT_BLOCKED indicates that a call to toggle_radio() can change
-that state. RFKILL_STATE_HARD_BLOCKED indicates that a call to toggle_radio()
-will not be able to change the state and will return with a suitable error if
-attempts are made to set the state to RFKILL_STATE_UNBLOCKED.
-
-RFKILL_STATE_HARD_BLOCKED is used by drivers to signal that the device is
-locked in the BLOCKED state by a hardwire rfkill line (typically an input pin
-that, when active, forces the transmitter to be disabled) which the driver
-CANNOT override.
-
-Full rfkill functionality requires two different subsystems to cooperate: the
-input layer and the rfkill class. The input layer issues *commands* to the
-entire system requesting that devices registered to the rfkill class change
-state. The way this interaction happens is not complex, but it is not obvious
-either:
-
-Kernel Input layer:
-
- * Generates KEY_WWAN, KEY_WLAN, KEY_BLUETOOTH, SW_RFKILL_ALL, and
- other such events when the user presses certain keys, buttons, or
- toggles certain physical switches.
-
- THE INPUT LAYER IS NEVER USED TO PROPAGATE STATUS, NOTIFICATIONS OR THE
- KIND OF STUFF AN ON-SCREEN-DISPLAY APPLICATION WOULD REPORT. It is
- used to issue *commands* for the system to change behaviour, and these
- commands may or may not be carried out by some kernel driver or
- userspace application. It follows that doing user feedback based only
- on input events is broken, as there is no guarantee that an input event
- will be acted upon.
-
- Most wireless communication device drivers implementing rfkill
- functionality MUST NOT generate these events, and have no reason to
- register themselves with the input layer. Doing otherwise is a common
- misconception. There is an API to propagate rfkill status change
- information, and it is NOT the input layer.
-
-rfkill class:
-
- * Calls a hook in a driver to effectively change the wireless
- transmitter state;
- * Keeps track of the wireless transmitter state (with help from
- the driver);
- * Generates userspace notifications (uevents) and a call to a
- notification chain (kernel) when there is a wireless transmitter
- state change;
- * Connects a wireless communications driver with the common rfkill
- control system, which, for example, allows actions such as
- "switch all bluetooth devices offline" to be carried out by
- userspace or by rfkill-input.
-
- THE RFKILL CLASS NEVER ISSUES INPUT EVENTS. THE RFKILL CLASS DOES
- NOT LISTEN TO INPUT EVENTS. NO DRIVER USING THE RFKILL CLASS SHALL
- EVER LISTEN TO, OR ACT ON RFKILL INPUT EVENTS. Doing otherwise is
- a layering violation.
-
- Most wireless data communication drivers in the kernel have just to
- implement the rfkill class API to work properly. Interfacing to the
- input layer is not often required (and is very often a *bug*) on
- wireless drivers.
-
- Platform drivers often have to attach to the input layer to *issue*
- (but never to listen to) rfkill events for rfkill switches, and also to
- the rfkill class to export a control interface for the platform rfkill
- controllers to the rfkill subsystem. This does NOT mean the rfkill
- switch is attached to a rfkill class (doing so is almost always wrong).
- It just means the same kernel module is the driver for different
- devices (rfkill switches and rfkill controllers).
-
-
-Userspace input handlers (uevents) or kernel input handlers (rfkill-input):
-
- * Implements the policy of what should happen when one of the input
- layer events related to rfkill operation is received.
- * Uses the sysfs interface (userspace) or private rfkill API calls
- to tell the devices registered with the rfkill class to change
- their state (i.e. translates the input layer event into real
- action).
-
- * rfkill-input implements EPO by handling EV_SW SW_RFKILL_ALL 0
- (power off all transmitters) in a special way: it ignores any
- overrides and local state cache and forces all transmitters to the
- RFKILL_STATE_SOFT_BLOCKED state (including those which are already
- supposed to be BLOCKED).
- * rfkill EPO will remain active until rfkill-input receives an
- EV_SW SW_RFKILL_ALL 1 event. While the EPO is active, transmitters
- are locked in the blocked state (rfkill will refuse to unblock them).
- * rfkill-input implements different policies that the user can
- select for handling EV_SW SW_RFKILL_ALL 1. It will unlock rfkill,
- and either do nothing (leave transmitters blocked, but now unlocked),
- restore the transmitters to their state before the EPO, or unblock
- them all.
-
-Userspace uevent handler or kernel platform-specific drivers hooked to the
-rfkill notifier chain:
-
- * Taps into the rfkill notifier chain or to KOBJ_CHANGE uevents,
- in order to know when a device that is registered with the rfkill
- class changes state;
- * Issues feedback notifications to the user;
- * In the rare platforms where this is required, synthesizes an input
- event to command all *OTHER* rfkill devices to also change their
- statues when a specific rfkill device changes state.
-
-
-===============================================================================
-3: Kernel driver guidelines
-
-Remember: point-of-view is everything for a driver that connects to the rfkill
-subsystem. All the details below must be measured/perceived from the point of
-view of the specific driver being modified.
-
-The first thing one needs to know is whether his driver should be talking to
-the rfkill class or to the input layer. In rare cases (platform drivers), it
-could happen that you need to do both, as platform drivers often handle a
-variety of devices in the same driver.
-
-Do not mistake input devices for rfkill controllers. The only type of "rfkill
-switch" device that is to be registered with the rfkill class are those
-directly controlling the circuits that cause a wireless transmitter to stop
-working (or the software equivalent of them), i.e. what we call a rfkill
-controller. Every other kind of "rfkill switch" is just an input device and
-MUST NOT be registered with the rfkill class.
-
-A driver should register a device with the rfkill class when ALL of the
-following conditions are met (they define a rfkill controller):
-
-1. The device is/controls a data communications wireless transmitter;
-
-2. The kernel can interact with the hardware/firmware to CHANGE the wireless
- transmitter state (block/unblock TX operation);
-
-3. The transmitter can be made to not emit any energy when "blocked":
- rfkill is not about blocking data transmissions, it is about blocking
- energy emission;
-
-A driver should register a device with the input subsystem to issue
-rfkill-related events (KEY_WLAN, KEY_BLUETOOTH, KEY_WWAN, KEY_WIMAX,
-SW_RFKILL_ALL, etc) when ALL of the folowing conditions are met:
-
-1. It is directly related to some physical device the user interacts with, to
- command the O.S./firmware/hardware to enable/disable a data communications
- wireless transmitter.
-
- Examples of the physical device are: buttons, keys and switches the user
- will press/touch/slide/switch to enable or disable the wireless
- communication device.
-
-2. It is NOT slaved to another device, i.e. there is no other device that
- issues rfkill-related input events in preference to this one.
-
- Please refer to the corner cases and examples section for more details.
-
-When in doubt, do not issue input events. For drivers that should generate
-input events in some platforms, but not in others (e.g. b43), the best solution
-is to NEVER generate input events in the first place. That work should be
-deferred to a platform-specific kernel module (which will know when to generate
-events through the rfkill notifier chain) or to userspace. This avoids the
-usual maintenance problems with DMI whitelisting.
-
-
-Corner cases and examples:
-====================================
-
-1. If the device is an input device that, because of hardware or firmware,
-causes wireless transmitters to be blocked regardless of the kernel's will, it
-is still just an input device, and NOT to be registered with the rfkill class.
-
-2. If the wireless transmitter switch control is read-only, it is an input
-device and not to be registered with the rfkill class (and maybe not to be made
-an input layer event source either, see below).
-
-3. If there is some other device driver *closer* to the actual hardware the
-user interacted with (the button/switch/key) to issue an input event, THAT is
-the device driver that should be issuing input events.
-
-E.g:
- [RFKILL slider switch] -- [GPIO hardware] -- [WLAN card rf-kill input]
- (platform driver) (wireless card driver)
-
-The user is closer to the RFKILL slide switch plaform driver, so the driver
-which must issue input events is the platform driver looking at the GPIO
-hardware, and NEVER the wireless card driver (which is just a slave). It is
-very likely that there are other leaves than just the WLAN card rf-kill input
-(e.g. a bluetooth card, etc)...
-
-On the other hand, some embedded devices do this:
-
- [RFKILL slider switch] -- [WLAN card rf-kill input]
- (wireless card driver)
-
-In this situation, the wireless card driver *could* register itself as an input
-device and issue rf-kill related input events... but in order to AVOID the need
-for DMI whitelisting, the wireless card driver does NOT do it. Userspace (HAL)
-or a platform driver (that exists only on these embedded devices) will do the
-dirty job of issuing the input events.
-
-
-COMMON MISTAKES in kernel drivers, related to rfkill:
-====================================
-
-1. NEVER confuse input device keys and buttons with input device switches.
-
- 1a. Switches are always set or reset. They report the current state
- (on position or off position).
-
- 1b. Keys and buttons are either in the pressed or not-pressed state, and
- that's it. A "button" that latches down when you press it, and
- unlatches when you press it again is in fact a switch as far as input
- devices go.
-
-Add the SW_* events you need for switches, do NOT try to emulate a button using
-KEY_* events just because there is no such SW_* event yet. Do NOT try to use,
-for example, KEY_BLUETOOTH when you should be using SW_BLUETOOTH instead.
-
-2. Input device switches (sources of EV_SW events) DO store their current state
-(so you *must* initialize it by issuing a gratuitous input layer event on
-driver start-up and also when resuming from sleep), and that state CAN be
-queried from userspace through IOCTLs. There is no sysfs interface for this,
-but that doesn't mean you should break things trying to hook it to the rfkill
-class to get a sysfs interface :-)
-
-3. Do not issue *_RFKILL_ALL events by default, unless you are sure it is the
-correct event for your switch/button. These events are emergency power-off
-events when they are trying to turn the transmitters off. An example of an
-input device which SHOULD generate *_RFKILL_ALL events is the wireless-kill
-switch in a laptop which is NOT a hotkey, but a real sliding/rocker switch.
-An example of an input device which SHOULD NOT generate *_RFKILL_ALL events by
-default, is any sort of hot key that is type-specific (e.g. the one for WLAN).
-
-
-3.1 Guidelines for wireless device drivers
-------------------------------------------
-
-(in this text, rfkill->foo means the foo field of struct rfkill).
-
-1. Each independent transmitter in a wireless device (usually there is only one
-transmitter per device) should have a SINGLE rfkill class attached to it.
-
-2. If the device does not have any sort of hardware assistance to allow the
-driver to rfkill the device, the driver should emulate it by taking all actions
-required to silence the transmitter.
-
-3. If it is impossible to silence the transmitter (i.e. it still emits energy,
-even if it is just in brief pulses, when there is no data to transmit and there
-is no hardware support to turn it off) do NOT lie to the users. Do not attach
-it to a rfkill class. The rfkill subsystem does not deal with data
-transmission, it deals with energy emission. If the transmitter is emitting
-energy, it is not blocked in rfkill terms.
-
-4. It doesn't matter if the device has multiple rfkill input lines affecting
-the same transmitter, their combined state is to be exported as a single state
-per transmitter (see rule 1).
-
-This rule exists because users of the rfkill subsystem expect to get (and set,
-when possible) the overall transmitter rfkill state, not of a particular rfkill
-line.
-
-5. The wireless device driver MUST NOT leave the transmitter enabled during
-suspend and hibernation unless:
+The rfkill class is provided for kernel drivers to register their radio
+transmitter with the kernel, provide methods for turning it on and off and,
+optionally, letting the system know about hardware-disabled states that may
+be implemented on the device. This code is enabled with the CONFIG_RFKILL
+Kconfig option, which drivers can "select".
- 5.1. The transmitter has to be enabled for some sort of functionality
- like wake-on-wireless-packet or autonomous packed forwarding in a mesh
- network, and that functionality is enabled for this suspend/hibernation
- cycle.
+The rfkill class code also notifies userspace of state changes, this is
+achieved via uevents. It also provides some sysfs files for userspace to
+check the status of radio transmitters. See the "Userspace support" section
+below.
-AND
- 5.2. The device was not on a user-requested BLOCKED state before
- the suspend (i.e. the driver must NOT unblock a device, not even
- to support wake-on-wireless-packet or remain in the mesh).
+The rfkill-input code implements a basic response to rfkill buttons -- it
+implements turning on/off all devices of a certain class (or all).
-In other words, there is absolutely no allowed scenario where a driver can
-automatically take action to unblock a rfkill controller (obviously, this deals
-with scenarios where soft-blocking or both soft and hard blocking is happening.
-Scenarios where hardware rfkill lines are the only ones blocking the
-transmitter are outside of this rule, since the wireless device driver does not
-control its input hardware rfkill lines in the first place).
+When the device is hard-blocked (either by a call to rfkill_set_hw_state()
+or from query_hw_block) set_block() will be invoked but drivers can well
+ignore the method call since they can use the return value of the function
+rfkill_set_hw_state() to sync the software state instead of keeping track
+of calls to set_block().
-6. During resume, rfkill will try to restore its previous state.
-7. After a rfkill class is suspended, it will *not* call rfkill->toggle_radio
-until it is resumed.
+The entire functionality is spread over more than one subsystem:
+ * The kernel input layer generates KEY_WWAN, KEY_WLAN etc. and
+ SW_RFKILL_ALL -- when the user presses a button. Drivers for radio
+ transmitters generally do not register to the input layer, unless the
+ device really provides an input device (i.e. a button that has no
+ effect other than generating a button press event)
-Example of a WLAN wireless driver connected to the rfkill subsystem:
---------------------------------------------------------------------
+ * The rfkill-input code hooks up to these events and switches the soft-block
+ of the various radio transmitters, depending on the button type.
-A certain WLAN card has one input pin that causes it to block the transmitter
-and makes the status of that input pin available (only for reading!) to the
-kernel driver. This is a hard rfkill input line (it cannot be overridden by
-the kernel driver).
+ * The rfkill drivers turn off/on their transmitters as requested.
-The card also has one PCI register that, if manipulated by the driver, causes
-it to block the transmitter. This is a soft rfkill input line.
+ * The rfkill class will generate userspace notifications (uevents) to tell
+ userspace what the current state is.
-It has also a thermal protection circuitry that shuts down its transmitter if
-the card overheats, and makes the status of that protection available (only for
-reading!) to the kernel driver. This is also a hard rfkill input line.
-If either one of these rfkill lines are active, the transmitter is blocked by
-the hardware and forced offline.
-The driver should allocate and attach to its struct device *ONE* instance of
-the rfkill class (there is only one transmitter).
+3. Kernel driver guidelines
-It can implement the get_state() hook, and return RFKILL_STATE_HARD_BLOCKED if
-either one of its two hard rfkill input lines are active. If the two hard
-rfkill lines are inactive, it must return RFKILL_STATE_SOFT_BLOCKED if its soft
-rfkill input line is active. Only if none of the rfkill input lines are
-active, will it return RFKILL_STATE_UNBLOCKED.
-Since the device has a hardware rfkill line, it IS subject to state changes
-external to rfkill. Therefore, the driver must make sure that it calls
-rfkill_force_state() to keep the status always up-to-date, and it must do a
-rfkill_force_state() on resume from sleep.
+Drivers for radio transmitters normally implement only the rfkill class.
+These drivers may not unblock the transmitter based on own decisions, they
+should act on information provided by the rfkill class only.
-Every time the driver gets a notification from the card that one of its rfkill
-lines changed state (polling might be needed on badly designed cards that don't
-generate interrupts for such events), it recomputes the rfkill state as per
-above, and calls rfkill_force_state() to update it.
+Platform drivers might implement input devices if the rfkill button is just
+that, a button. If that button influences the hardware then you need to
+implement an rfkill class instead. This also applies if the platform provides
+a way to turn on/off the transmitter(s).
-The driver should implement the toggle_radio() hook, that:
+During suspend/hibernation, transmitters should only be left enabled when
+wake-on wlan or similar functionality requires it and the device wasn't
+blocked before suspend/hibernate. Note that it may be necessary to update
+the rfkill subsystem's idea of what the current state is at resume time if
+the state may have changed over suspend.
-1. Returns an error if one of the hardware rfkill lines are active, and the
-caller asked for RFKILL_STATE_UNBLOCKED.
-2. Activates the soft rfkill line if the caller asked for state
-RFKILL_STATE_SOFT_BLOCKED. It should do this even if one of the hard rfkill
-lines are active, effectively double-blocking the transmitter.
-3. Deactivates the soft rfkill line if none of the hardware rfkill lines are
-active and the caller asked for RFKILL_STATE_UNBLOCKED.
-
-===============================================================================
-4: Kernel API
+4. Kernel API
To build a driver with rfkill subsystem support, the driver should depend on
-(or select) the Kconfig symbol RFKILL; it should _not_ depend on RKFILL_INPUT.
+(or select) the Kconfig symbol RFKILL.
The hardware the driver talks to may be write-only (where the current state
of the hardware is unknown), or read-write (where the hardware can be queried
about its current state).
-The rfkill class will call the get_state hook of a device every time it needs
-to know the *real* current state of the hardware. This can happen often, but
-it does not do any polling, so it is not enough on hardware that is subject
-to state changes outside of the rfkill subsystem.
-
-Therefore, calling rfkill_force_state() when a state change happens is
-mandatory when the device has a hardware rfkill line, or when something else
-like the firmware could cause its state to be changed without going through the
-rfkill class.
-
-Some hardware provides events when its status changes. In these cases, it is
-best for the driver to not provide a get_state hook, and instead register the
-rfkill class *already* with the correct status, and keep it updated using
-rfkill_force_state() when it gets an event from the hardware.
-
-rfkill_force_state() must be used on the device resume handlers to update the
-rfkill status, should there be any chance of the device status changing during
-the sleep.
-
-There is no provision for a statically-allocated rfkill struct. You must
-use rfkill_allocate() to allocate one.
-
-You should:
- - rfkill_allocate()
- - modify rfkill fields (flags, name)
- - modify state to the current hardware state (THIS IS THE ONLY TIME
- YOU CAN ACCESS state DIRECTLY)
- - rfkill_register()
-
-The only way to set a device to the RFKILL_STATE_HARD_BLOCKED state is through
-a suitable return of get_state() or through rfkill_force_state().
+Calling rfkill_set_hw_state() when a state change happens is required from
+rfkill drivers that control devices that can be hard-blocked unless they also
+assign the poll_hw_block() callback (then the rfkill core will poll the
+device). Don't do this unless you cannot get the event in any other way.
-When a device is in the RFKILL_STATE_HARD_BLOCKED state, the only way to switch
-it to a different state is through a suitable return of get_state() or through
-rfkill_force_state().
-If toggle_radio() is called to set a device to state RFKILL_STATE_SOFT_BLOCKED
-when that device is already at the RFKILL_STATE_HARD_BLOCKED state, it should
-not return an error. Instead, it should try to double-block the transmitter,
-so that its state will change from RFKILL_STATE_HARD_BLOCKED to
-RFKILL_STATE_SOFT_BLOCKED should the hardware blocking cease.
-
-Please refer to the source for more documentation.
-
-===============================================================================
-5: Userspace support
-
-rfkill devices issue uevents (with an action of "change"), with the following
-environment variables set:
-
-RFKILL_NAME
-RFKILL_STATE
-RFKILL_TYPE
-The ABI for these variables is defined by the sysfs attributes. It is best
-to take a quick look at the source to make sure of the possible values.
+5. Userspace support
-It is expected that HAL will trap those, and bridge them to DBUS, etc. These
-events CAN and SHOULD be used to give feedback to the user about the rfkill
-status of the system.
-
-Input devices may issue events that are related to rfkill. These are the
-various KEY_* events and SW_* events supported by rfkill-input.c.
-
-******IMPORTANT******
-When rfkill-input is ACTIVE, userspace is NOT TO CHANGE THE STATE OF AN RFKILL
-SWITCH IN RESPONSE TO AN INPUT EVENT also handled by rfkill-input, unless it
-has set to true the user_claim attribute for that particular switch. This rule
-is *absolute*; do NOT violate it.
-******IMPORTANT******
-
-Userspace must not assume it is the only source of control for rfkill switches.
-Their state CAN and WILL change due to firmware actions, direct user actions,
-and the rfkill-input EPO override for *_RFKILL_ALL.
-
-When rfkill-input is not active, userspace must initiate a rfkill status
-change by writing to the "state" attribute in order for anything to happen.
-
-Take particular care to implement EV_SW SW_RFKILL_ALL properly. When that
-switch is set to OFF, *every* rfkill device *MUST* be immediately put into the
-RFKILL_STATE_SOFT_BLOCKED state, no questions asked.
-
-The following sysfs entries will be created:
+The following sysfs entries exist for every rfkill device:
name: Name assigned by driver to this key (interface or driver name).
type: Name of the key type ("wlan", "bluetooth", etc).
state: Current state of the transmitter
0: RFKILL_STATE_SOFT_BLOCKED
- transmitter is forced off, but one can override it
- by a write to the state attribute;
+ transmitter is turned off by software
1: RFKILL_STATE_UNBLOCKED
- transmiter is NOT forced off, and may operate if
- all other conditions for such operation are met
- (such as interface is up and configured, etc);
+ transmitter is (potentially) active
2: RFKILL_STATE_HARD_BLOCKED
transmitter is forced off by something outside of
- the driver's control. One cannot set a device to
- this state through writes to the state attribute;
- claim: 1: Userspace handles events, 0: Kernel handles events
-
-Both the "state" and "claim" entries are also writable. For the "state" entry
-this means that when 1 or 0 is written, the device rfkill state (if not yet in
-the requested state), will be will be toggled accordingly.
-
-For the "claim" entry writing 1 to it means that the kernel no longer handles
-key events even though RFKILL_INPUT input was enabled. When "claim" has been
-set to 0, userspace should make sure that it listens for the input events or
-check the sysfs "state" entry regularly to correctly perform the required tasks
-when the rkfill key is pressed.
-
-A note about input devices and EV_SW events:
-
-In order to know the current state of an input device switch (like
-SW_RFKILL_ALL), you will need to use an IOCTL. That information is not
-available through sysfs in a generic way at this time, and it is not available
-through the rfkill class AT ALL.
+ the driver's control.
+ claim: 0: Kernel handles events (currently always reads that value)
+
+rfkill devices also issue uevents (with an action of "change"), with the
+following environment variables set:
+
+RFKILL_NAME
+RFKILL_STATE
+RFKILL_TYPE
+
+The contents of these variables corresponds to the "name", "state" and
+"type" sysfs files explained above.
+
+An alternative userspace interface exists as a misc device /dev/rfkill,
+which allows userspace to obtain and set the state of rfkill devices and
+sets of devices. It also notifies userspace about device addition and
+removal. The API is a simple read/write API that is defined in
+linux/rfkill.h.
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