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Diffstat (limited to '')
| -rw-r--r-- | Documentation/networking/nfc.rst (renamed from Documentation/networking/nfc.txt) | 74 |
1 files changed, 38 insertions, 36 deletions
diff --git a/Documentation/networking/nfc.txt b/Documentation/networking/nfc.rst index b24c29bdae27..9aab3a88c9b2 100644 --- a/Documentation/networking/nfc.txt +++ b/Documentation/networking/nfc.rst @@ -1,3 +1,4 @@ +=================== Linux NFC subsystem =================== @@ -8,7 +9,7 @@ This document covers the architecture overview, the device driver interface description and the userspace interface description. Architecture overview ---------------------- +===================== The NFC subsystem is responsible for: - NFC adapters management; @@ -25,33 +26,34 @@ The control operations are available to userspace via generic netlink. The low-level data exchange interface is provided by the new socket family PF_NFC. The NFC_SOCKPROTO_RAW performs raw communication with NFC targets. - - +--------------------------------------+ - | USER SPACE | - +--------------------------------------+ - ^ ^ - | low-level | control - | data exchange | operations - | | - | v - | +-----------+ - | AF_NFC | netlink | - | socket +-----------+ - | raw ^ - | | - v v - +---------+ +-----------+ - | rawsock | <--------> | core | - +---------+ +-----------+ - ^ - | - v - +-----------+ - | driver | - +-----------+ +.. code-block:: none + + +--------------------------------------+ + | USER SPACE | + +--------------------------------------+ + ^ ^ + | low-level | control + | data exchange | operations + | | + | v + | +-----------+ + | AF_NFC | netlink | + | socket +-----------+ + | raw ^ + | | + v v + +---------+ +-----------+ + | rawsock | <--------> | core | + +---------+ +-----------+ + ^ + | + v + +-----------+ + | driver | + +-----------+ Device Driver Interface ------------------------ +======================= When registering on the NFC subsystem, the device driver must inform the core of the set of supported NFC protocols and the set of ops callbacks. The ops @@ -64,7 +66,7 @@ callbacks that must be implemented are the following: * data_exchange - send data and receive the response (transceive operation) Userspace interface --------------------- +=================== The userspace interface is divided in control operations and low-level data exchange operation. @@ -82,7 +84,7 @@ The operations are composed by commands and events, all listed below: * NFC_EVENT_DEVICE_ADDED - reports an NFC device addition * NFC_EVENT_DEVICE_REMOVED - reports an NFC device removal * NFC_EVENT_TARGETS_FOUND - reports START_POLL results when 1 or more targets -are found + are found The user must call START_POLL to poll for NFC targets, passing the desired NFC protocols through NFC_ATTR_PROTOCOLS attribute. The device remains in polling @@ -101,14 +103,14 @@ it's closed. LOW-LEVEL DATA EXCHANGE: The userspace must use PF_NFC sockets to perform any data communication with -targets. All NFC sockets use AF_NFC: - -struct sockaddr_nfc { - sa_family_t sa_family; - __u32 dev_idx; - __u32 target_idx; - __u32 nfc_protocol; -}; +targets. All NFC sockets use AF_NFC:: + + struct sockaddr_nfc { + sa_family_t sa_family; + __u32 dev_idx; + __u32 target_idx; + __u32 nfc_protocol; + }; To establish a connection with one target, the user must create an NFC_SOCKPROTO_RAW socket and call the 'connect' syscall with the sockaddr_nfc |