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authorEric Lapuyade <eric.lapuyade@intel.com>2012-05-07 12:31:17 +0200
committerJohn W. Linville <linville@tuxdriver.com>2012-05-15 17:28:01 -0400
commita202abb1ee98ee28faaca460bbbf684d05e94310 (patch)
tree90349d7b1b528bede1f49be97b91f239a0e6ddd1 /Documentation/nfc
parent1676f75159c8091e865c33b61ad4934dfd3b7821 (diff)
downloadlinux-linaro-stable-a202abb1ee98ee28faaca460bbbf684d05e94310.tar.gz
NFC: Update Documentation/nfc-hci.txt
Document the new HCI ops and fix a few typos and spelling mistakes. Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'Documentation/nfc')
-rw-r--r--Documentation/nfc/nfc-hci.txt45
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.