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struct net_if_api | iface_api |
| network interface API
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enum ieee802154_hw_caps(* | get_capabilities )(const struct device *dev) |
| Get the device driver capabilities.
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int(* | cca )(const struct device *dev) |
| Clear Channel Assessment - Check channel's activity.
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int(* | set_channel )(const struct device *dev, uint16_t channel) |
| Set current channel.
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int(* | filter )(const struct device *dev, bool set, enum ieee802154_filter_type type, const struct ieee802154_filter *filter) |
| Set/Unset PAN ID, extended or short address filters.
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int(* | set_txpower )(const struct device *dev, int16_t dbm) |
| Set TX power level in dbm.
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int(* | tx )(const struct device *dev, enum ieee802154_tx_mode mode, struct net_pkt *pkt, struct net_buf *frag) |
| Transmit a packet fragment as a single frame.
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int(* | start )(const struct device *dev) |
| Start the device.
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int(* | stop )(const struct device *dev) |
| Stop the device.
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int(* | continuous_carrier )(const struct device *dev) |
| Start continuous carrier wave transmission.
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int(* | configure )(const struct device *dev, enum ieee802154_config_type type, const struct ieee802154_config *config) |
| Set or update driver configuration.
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int(* | ed_scan )(const struct device *dev, uint16_t duration, energy_scan_done_cb_t done_cb) |
| Run an energy detection scan.
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net_time_t(* | get_time )(const struct device *dev) |
| Get the current time in nanoseconds relative to the network subsystem's local uptime clock as represented by this network interface.
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uint8_t(* | get_sch_acc )(const struct device *dev) |
| Get the current estimated worst case accuracy (maximum ± deviation from the nominal frequency) of the network subsystem's local clock used to calculate tolerances and guard times when scheduling delayed receive or transmit radio operations.
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int(* | attr_get )(const struct device *dev, enum ieee802154_attr attr, struct ieee802154_attr_value *value) |
| Get the value of a driver specific attribute.
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IEEE 802.15.4 driver interface API.
- Note
- This structure is called "radio" API for backwards compatibility. A better name would be "IEEE 802.15.4 driver API" as typical drivers will not only implement L1/radio (PHY) features but also L2 (MAC) features if the vendor-specific driver hardware or firmware offers offloading opportunities.
While L1-level driver features are exclusively implemented by drivers and MAY be mandatory to support certain application requirements, L2 features SHOULD be optional by default and only need to be implemented for performance optimization or precise timing as deemed necessary by driver maintainers. Fallback implementations ("Soft MAC") SHOULD be provided in the driver-independent L2 layer for all L2/MAC features especially if these features are not implemented in vendor hardware/firmware by a majority of existing in-tree drivers. If, however, a driver offers offloading opportunities then L2 implementations SHALL delegate performance critical or resource intensive tasks to the driver.
All drivers SHALL support two externally observable interface operational states: "UP" and "DOWN". Drivers MAY additionally support a "TESTING" interface state (see continuous_carrier()
).
The following rules apply:
- An interface is considered "UP" when it is able to transmit and receive packets, "DOWN" otherwise (see precise definitions of the corresponding ifOperStatus values in RFC 2863, section 3.1.14, net_if_oper_state and the
continuous_carrier()
exception below). A device that has its receiver temporarily disabled during "UP" state due to an active receive window configuration is still considered "UP".
- Upper layers will assume that the interface managed by the driver is "UP" after a call to
start()
returned zero or -EALREADY
. Upper layers assume that the interface is "DOWN" after calling stop()
returned zero or -EALREADY
.
- The driver SHALL block
start()
/stop()
calls until the interface fully transitioned to the new state (e.g. the receiver is operational, ongoing transmissions were finished, etc.). Drivers SHOULD yield the calling thread (i.e. "sleep") if waiting for the new state without CPU interaction is possible.
- Drivers are responsible of guaranteeing atomicity of state changes. Appropriate means of synchronization SHALL be implemented (locking, atomic flags, ...).
- While the interface is "DOWN", the driver SHALL be placed in the lowest possible power state. The driver MAY return from a call to
stop()
before it reaches the lowest possible power state, i.e. manage power asynchronously. While the interface is "UP", the driver SHOULD autonomously and asynchronously transition to lower power states whenever possible. If the driver claims to support timed RX/TX capabilities and the upper layers configure an RX slot, then the driver SHALL immediately transition (asynchronously) to the lowest possible power state until the start of the RX slot or until a scheduled packet needs to be transmitted.
- The driver SHALL NOT change the interface's "UP"/"DOWN" state on its own. Initially, the interface SHALL be in the "DOWN" state.
- Drivers that implement the optional
continuous_carrier()
operation will be considered to be in the RFC 2863 "testing" ifOperStatus state if that operation returns zero. This state is active until either start()
or stop()
is called. If continuous_carrier()
returns a non-zero value then the previous state is assumed by upper layers.
- If calls to
start()
/stop()
return any other value than zero or -EALREADY
, upper layers will consider the interface to be in a "lowerLayerDown" state as defined in RFC 2863.
- The RFC 2863 "dormant", "unknown" and "notPresent" ifOperStatus states are currently not supported. The "lowerLevelUp" state.
- The
ed_scan()
, cca()
and tx()
operations SHALL only be supported in the "UP" state and return -ENETDOWN
in any other state. See the function-level API documentation below for further details.
- Note
- In case of devices that support timed RX/TX, the "UP" state is not equal to "receiver enabled". If a receive window (i.e. RX slot, see IEEE802154_CONFIG_RX_SLOT) is configured before calling
start()
then the receiver will not be enabled when transitioning to the "UP" state. Configuring a receive window while the interface is "UP" will cause the receiver to be disabled immediately until the configured reception time has arrived.
Transmit a packet fragment as a single frame.
Depending on the level of offloading features supported by the driver, the frame MAY not be fully encrypted/authenticated or it MAY not contain an FCS. It is the responsibility of L2 implementations to prepare the frame according to the offloading capabilities announced by the driver and to decide whether CCA, CSMA/CA, ACK or retransmission procedures need to be executed outside ("soft MAC") or inside ("hard MAC") the driver .
All frames originating from L2 SHALL have all required IEs pre-allocated and pre-filled such that the driver does not have to parse and manipulate IEs at all. This includes ACK packets if the driver does not have the IEEE802154_HW_RX_TX_ACK capability. Also see IEEE802154_CONFIG_ENH_ACK_HEADER_IE for drivers that have the IEEE802154_HW_RX_TX_ACK capability.
IEs that cannot be prepared by L2 unless the TX time is known (e.g. CSL IE, Rendezvous Time IE, Time Correction IE, ...) SHALL be sent in any of the timed TX modes with appropriate timing information pre-filled in the IE such that drivers do not have to parse and manipulate IEs at all unless the frame is generated by the driver itself.
In case any of the timed TX modes is supported and used (see ieee802154_hw_caps and ieee802154_tx_mode), the driver SHALL take responsibility of scheduling and sending the packet at the precise programmed time autonomously without further interaction by upper layers. The call to tx()
will block until the package has either been sent successfully (possibly including channel acquisition and packet acknowledgment) or a terminal transmission error occurred. The driver SHALL sleep and keep power consumption to the lowest possible level until the scheduled transmission time arrives or during any other idle waiting time.
- Warning
- The driver SHALL NOT take ownership of the given network packet and frame (fragment) buffer. Any data required by the driver including the actual frame content must be read synchronously and copied internally if needed at a later time (e.g. the contents of IEs required for protocol configuration, states of frame counters, sequence numbers, etc). Both, the packet and the buffer MAY be re-used or released by upper layers immediately after the function returns.
- Note
- Implementations MAY sleep and will usually NOT be isr-ok - especially when timed TX, CSMA/CA, retransmissions, auto-ACK or any other offloading feature is supported that implies considerable idle waiting time. SHALL return
-ENETDOWN
unless the interface is "UP".
- Parameters
-
dev | pointer to IEEE 802.15.4 driver device |
mode | the transmission mode, some of which require specific offloading capabilities. |
pkt | pointer to the network packet to be transmitted. |
frag | pointer to a network buffer containing a single fragment with the frame data to be transmitted |
- Return values
-
0 | The frame was successfully sent or scheduled. If the driver supports ACK offloading and the frame requested acknowlegment (AR bit set), this means that the packet was successfully acknowledged by its peer. |
-EINVAL | Invalid packet (e.g. an expected IE is missing or the encryption/authentication state is not as expected). |
-EBUSY | The frame could not be sent because the medium was busy (CSMA/CA or CCA offloading feature only). |
-ENOMSG | The frame was not confirmed by an ACK packet (TX ACK offloading feature only) or the received ACK packet was invalid. |
-ENOBUFS | The frame could not be scheduled due to missing internal resources (timed TX offloading feature only). |
-ENETDOWN | The interface is not "UP". |
-ENOTSUP | The given TX mode is not supported. |
-EIO | The frame could not be sent due to some unspecified driver error (e.g. the driver being busy). |