diff options
Diffstat (limited to 'Documentation/nfc/nfc-hci.txt')
| -rw-r--r-- | Documentation/nfc/nfc-hci.txt | 45 |
1 files changed, 35 insertions, 10 deletions
diff --git a/Documentation/nfc/nfc-hci.txt b/Documentation/nfc/nfc-hci.txt index 216b7254fcc3..320f9336c781 100644 --- a/Documentation/nfc/nfc-hci.txt +++ b/Documentation/nfc/nfc-hci.txt @@ -22,9 +22,9 @@ response to arrive. HCI events can also be received from the host controller. They will be handled and a translation will be forwarded to NFC Core as needed. HCI uses 2 execution contexts: -- one if for executing commands : nfc_hci_msg_tx_work(). Only one command +- one for executing commands : nfc_hci_msg_tx_work(). Only one command can be executing at any given moment. -- one if for dispatching received events and responses : nfc_hci_msg_rx_work() +- one for dispatching received events and commands : nfc_hci_msg_rx_work(). HCI Session initialization: --------------------------- @@ -52,18 +52,42 @@ entry points: struct nfc_hci_ops { int (*open)(struct nfc_hci_dev *hdev); void (*close)(struct nfc_hci_dev *hdev); + int (*hci_ready) (struct nfc_hci_dev *hdev); int (*xmit)(struct nfc_hci_dev *hdev, struct sk_buff *skb); int (*start_poll)(struct nfc_hci_dev *hdev, u32 protocols); int (*target_from_gate)(struct nfc_hci_dev *hdev, u8 gate, struct nfc_target *target); + int (*complete_target_discovered) (struct nfc_hci_dev *hdev, u8 gate, + struct nfc_target *target); + int (*data_exchange) (struct nfc_hci_dev *hdev, + struct nfc_target *target, + struct sk_buff *skb, struct sk_buff **res_skb); + int (*check_presence)(struct nfc_hci_dev *hdev, + struct nfc_target *target); }; -open() and close() shall turn the hardware on and off. xmit() shall simply -write a frame to the chip. start_poll() is an optional entrypoint that shall -set the hardware in polling mode. This must be implemented only if the hardware -uses proprietary gates or a mechanism slightly different from the HCI standard. -target_from_gate() is another optional entrypoint to return the protocols +- open() and close() shall turn the hardware on and off. +- hci_ready() is an optional entry point that is called right after the hci +session has been set up. The driver can use it to do additional initialization +that must be performed using HCI commands. +- xmit() shall simply write a frame to the chip. +- start_poll() is an optional entrypoint that shall set the hardware in polling +mode. This must be implemented only if the hardware uses proprietary gates or a +mechanism slightly different from the HCI standard. +- target_from_gate() is an optional entrypoint to return the nfc protocols corresponding to a proprietary gate. +- complete_target_discovered() is an optional entry point to let the driver +perform additional proprietary processing necessary to auto activate the +discovered target. +- data_exchange() must be implemented by the driver if proprietary HCI commands +are required to send data to the tag. Some tag types will require custom +commands, others can be written to using the standard HCI commands. The driver +can check the tag type and either do proprietary processing, or return 1 to ask +for standard processing. +- check_presence() is an optional entry point that will be called regularly +by the core to check that an activated tag is still in the field. If this is +not implemented, the core will not be able to push tag_lost events to the user +space On the rx path, the driver is responsible to push incoming HCP frames to HCI using nfc_hci_recv_frame(). HCI will take care of re-aggregation and handling @@ -99,7 +123,8 @@ fast, cannot sleep. stores incoming frames into an shdlc rx queue handles shdlc rx & tx queues. Dispatches HCI cmd responses. - HCI Tx Cmd worker (MSGTXWQ) -Serialize execution of HCI commands. Complete execution in case of resp timeout. +Serializes execution of HCI commands. Completes execution in case of response +timeout. - HCI Rx worker (MSGRXWQ) Dispatches incoming HCI commands or events. @@ -133,11 +158,11 @@ able to complete the command with a timeout error if no response arrive. SMW context gets scheduled and invokes nfc_shdlc_sm_work(). This function handles shdlc framing in and out. It uses the driver xmit to send frames and receives incoming frames in an skb queue filled from the driver IRQ handler. -SHDLC I(nformation) frames payload are HCP fragments. They are agregated to +SHDLC I(nformation) frames payload are HCP fragments. They are aggregated to form complete HCI frames, which can be a response, command, or event. HCI Responses are dispatched immediately from this context to unblock -waiting command execution. Reponse processing involves invoking the completion +waiting command execution. Response processing involves invoking the completion callback that was provided by nfc_hci_msg_tx_work() when it sent the command. The completion callback will then wake the syscall context. |