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linux/include/net/nfc/digital.h
Thierry Escande 2c66daecc4 NFC Digital: Add NFC-A technology support 
This adds support for NFC-A technology at 106 kbits/s. The stack can
detect tags of type 1 and 2. There is no support for collision
detection. Tags can be read and written by using a user space
application or a daemon like neard.

The flow of polling operations for NFC-A detection is as follow:

1 - The digital stack sends the SENS_REQ command to the NFC device.
2 - The NFC device receives a SENS_RES response from a peer device and
    passes it to the digital stack.
3   - If the SENS_RES response identifies a type 1 tag, detection ends.
      NFC core is notified through nfc_targets_found().
4   - Otherwise, the digital stack sets the cascade level of NFCID1 to
      CL1 and sends the SDD_REQ command.
5 - The digital stack selects SEL_CMD and SEL_PAR according to the
    cascade level and sends the SDD_REQ command.
4 - The digital stack receives a SDD_RES response for the cascade level
    passed in the SDD_REQ command.
5 - The digital stack analyses (part of) NFCID1 and verify BCC.
6 - The digital stack sends the SEL_REQ command with the NFCID1
    received in the SDD_RES.
6 - The peer device replies with a SEL_RES response
7   - Detection ends if NFCID1 is complete. NFC core notified of new
      target by nfc_targets_found().
8   - If NFCID1 is not complete, the cascade level is incremented (up
      to and including CL3) and the execution continues at step 5 to
      get the remaining bytes of NFCID1.

Once target detection is done, type 1 and 2 tag commands must be
handled by a user space application (i.e neard) through the NFC core.
Responses for type 1 tag are returned directly to user space via NFC
core.
Responses of type 2 commands are handled differently. The digital stack
doesn't analyse the type of commands sent through im_transceive() and
must differentiate valid responses from error ones.
The response process flow is as follow:

1 - If the response length is 16 bytes, it is a valid response of a
    READ command. the packet is returned to the NFC core through the
    callback passed to im_transceive(). Processing stops.
2 - If the response is 1 byte long and is a ACK byte (0x0A), it is a
    valid response of a WRITE command for example. First packet byte
    is set to 0 for no-error and passed back to the NFC core.
    Processing stops.
3 - Any other response is treated as an error and -EIO error code is
    returned to the NFC core through the response callback.

Moreover, since the driver can't differentiate success response from a
NACK response, the digital stack has to handle CRC calculation.

Thus, this patch also adds support for CRC calculation. If the driver
doesn't handle it, the digital stack will calculate CRC and will add it
to sent frames. CRC will also be checked and removed from received
frames. Pointers to the correct CRC calculation functions are stored in
the digital stack device structure when a target is detected. This
avoids the need to check the current target type for every call to
im_transceive() and for every response received from a peer device.

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2013-09-25 02:02:23 +02:00

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/*
* NFC Digital Protocol stack
* Copyright (c) 2013, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
*/
#ifndef __NFC_DIGITAL_H
#define __NFC_DIGITAL_H
#include <linux/skbuff.h>
#include <net/nfc/nfc.h>
/**
* Configuration types for in_configure_hw and tg_configure_hw.
*/
enum {
NFC_DIGITAL_CONFIG_RF_TECH = 0,
NFC_DIGITAL_CONFIG_FRAMING,
};
/**
* RF technology values passed as param argument to in_configure_hw and
* tg_configure_hw for NFC_DIGITAL_CONFIG_RF_TECH configuration type.
*/
enum {
NFC_DIGITAL_RF_TECH_106A = 0,
NFC_DIGITAL_RF_TECH_212F,
NFC_DIGITAL_RF_TECH_424F,
NFC_DIGITAL_RF_TECH_LAST,
};
/**
* Framing configuration passed as param argument to in_configure_hw and
* tg_configure_hw for NFC_DIGITAL_CONFIG_FRAMING configuration type.
*/
enum {
NFC_DIGITAL_FRAMING_NFCA_SHORT = 0,
NFC_DIGITAL_FRAMING_NFCA_STANDARD,
NFC_DIGITAL_FRAMING_NFCA_STANDARD_WITH_CRC_A,
NFC_DIGITAL_FRAMING_NFCA_T1T,
NFC_DIGITAL_FRAMING_NFCA_T2T,
NFC_DIGITAL_FRAMING_NFCA_NFC_DEP,
NFC_DIGITAL_FRAMING_NFCF,
NFC_DIGITAL_FRAMING_NFCF_T3T,
NFC_DIGITAL_FRAMING_NFCF_NFC_DEP,
NFC_DIGITAL_FRAMING_NFC_DEP_ACTIVATED,
NFC_DIGITAL_FRAMING_LAST,
};
#define DIGITAL_MDAA_NFCID1_SIZE 3
struct digital_tg_mdaa_params {
u16 sens_res;
u8 nfcid1[DIGITAL_MDAA_NFCID1_SIZE];
u8 sel_res;
u8 nfcid2[NFC_NFCID2_MAXSIZE];
u16 sc;
};
struct nfc_digital_dev;
/**
* nfc_digital_cmd_complete_t - Definition of command result callback
*
* @ddev: nfc_digital_device ref
* @arg: user data
* @resp: response data
*
* resp pointer can be an error code and will be checked with IS_ERR() macro.
* The callback is responsible for freeing resp sk_buff.
*/
typedef void (*nfc_digital_cmd_complete_t)(struct nfc_digital_dev *ddev,
void *arg, struct sk_buff *resp);
/**
* Device side NFC Digital operations
*
* Initiator mode:
* @in_configure_hw: Hardware configuration for RF technology and communication
* framing in initiator mode. This is a synchronous function.
* @in_send_cmd: Initiator mode data exchange using RF technology and framing
* previously set with in_configure_hw. The peer response is returned
* through callback cb. If an io error occurs or the peer didn't reply
* within the specified timeout (ms), the error code is passed back through
* the resp pointer. This is an asynchronous function.
*
* Target mode: Only NFC-DEP protocol is supported in target mode.
* @tg_configure_hw: Hardware configuration for RF technology and communication
* framing in target mode. This is a synchronous function.
* @tg_send_cmd: Target mode data exchange using RF technology and framing
* previously set with tg_configure_hw. The peer next command is returned
* through callback cb. If an io error occurs or the peer didn't reply
* within the specified timeout (ms), the error code is passed back through
* the resp pointer. This is an asynchronous function.
* @tg_listen: Put the device in listen mode waiting for data from the peer
* device. This is an asynchronous function.
* @tg_listen_mdaa: If supported, put the device in automatic listen mode with
* mode detection and automatic anti-collision. In this mode, the device
* automatically detects the RF technology and executes the anti-collision
* detection using the command responses specified in mdaa_params. The
* mdaa_params structure contains SENS_RES, NFCID1, and SEL_RES for 106A RF
* tech. NFCID2 and system code (sc) for 212F and 424F. The driver returns
* the NFC-DEP ATR_REQ command through cb. The digital stack deducts the RF
* tech by analyzing the SoD of the frame containing the ATR_REQ command.
* This is an asynchronous function.
*
* @switch_rf: Turns device radio on or off. The stack does not call explicitly
* switch_rf to turn the radio on. A call to in|tg_configure_hw must turn
* the device radio on.
* @abort_cmd: Discard the last sent command.
*/
struct nfc_digital_ops {
int (*in_configure_hw)(struct nfc_digital_dev *ddev, int type,
int param);
int (*in_send_cmd)(struct nfc_digital_dev *ddev, struct sk_buff *skb,
u16 timeout, nfc_digital_cmd_complete_t cb,
void *arg);
int (*tg_configure_hw)(struct nfc_digital_dev *ddev, int type,
int param);
int (*tg_send_cmd)(struct nfc_digital_dev *ddev, struct sk_buff *skb,
u16 timeout, nfc_digital_cmd_complete_t cb,
void *arg);
int (*tg_listen)(struct nfc_digital_dev *ddev, u16 timeout,
nfc_digital_cmd_complete_t cb, void *arg);
int (*tg_listen_mdaa)(struct nfc_digital_dev *ddev,
struct digital_tg_mdaa_params *mdaa_params,
u16 timeout, nfc_digital_cmd_complete_t cb,
void *arg);
int (*switch_rf)(struct nfc_digital_dev *ddev, bool on);
void (*abort_cmd)(struct nfc_digital_dev *ddev);
};
#define NFC_DIGITAL_POLL_MODE_COUNT_MAX 6 /* 106A, 212F, and 424F in & tg */
typedef int (*digital_poll_t)(struct nfc_digital_dev *ddev, u8 rf_tech);
struct digital_poll_tech {
u8 rf_tech;
digital_poll_t poll_func;
};
/**
* Driver capabilities - bit mask made of the following values
*
* @NFC_DIGITAL_DRV_CAPS_IN_CRC: The driver handles CRC calculation in initiator
* mode.
* @NFC_DIGITAL_DRV_CAPS_TG_CRC: The driver handles CRC calculation in target
* mode.
*/
#define NFC_DIGITAL_DRV_CAPS_IN_CRC 0x0001
#define NFC_DIGITAL_DRV_CAPS_TG_CRC 0x0002
struct nfc_digital_dev {
struct nfc_dev *nfc_dev;
struct nfc_digital_ops *ops;
u32 protocols;
int tx_headroom;
int tx_tailroom;
u32 driver_capabilities;
void *driver_data;
struct digital_poll_tech poll_techs[NFC_DIGITAL_POLL_MODE_COUNT_MAX];
u8 poll_tech_count;
u8 poll_tech_index;
struct mutex poll_lock;
struct work_struct cmd_work;
struct work_struct cmd_complete_work;
struct list_head cmd_queue;
struct mutex cmd_lock;
struct work_struct poll_work;
u8 curr_protocol;
u8 curr_rf_tech;
u8 curr_nfc_dep_pni;
int (*skb_check_crc)(struct sk_buff *skb);
void (*skb_add_crc)(struct sk_buff *skb);
};
struct nfc_digital_dev *nfc_digital_allocate_device(struct nfc_digital_ops *ops,
__u32 supported_protocols,
__u32 driver_capabilities,
int tx_headroom,
int tx_tailroom);
void nfc_digital_free_device(struct nfc_digital_dev *ndev);
int nfc_digital_register_device(struct nfc_digital_dev *ndev);
void nfc_digital_unregister_device(struct nfc_digital_dev *ndev);
static inline void nfc_digital_set_parent_dev(struct nfc_digital_dev *ndev,
struct device *dev)
{
nfc_set_parent_dev(ndev->nfc_dev, dev);
}
static inline void nfc_digital_set_drvdata(struct nfc_digital_dev *dev,
void *data)
{
dev->driver_data = data;
}
static inline void *nfc_digital_get_drvdata(struct nfc_digital_dev *dev)
{
return dev->driver_data;
}
#endif /* __NFC_DIGITAL_H */
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