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7d0911c02f
linux-next/net/nfc/digital_dep.c
Thierry Escande 7d0911c02f NFC Digital: Add initiator NFC-DEP support 
This adds support for NFC-DEP protocol in initiator mode for NFC-A and
NFC-F technologies.

When a target is detected, the process flow is as follow:

For NFC-A technology:
1 - The digital stack receives a SEL_RES as the reply of the SEL_REQ
    command.
2   - If b7 of SEL_RES is set, the peer device is configure for NFC-DEP
      protocol. NFC core is notified through nfc_targets_found().
      Execution continues at step 4.
3   - Otherwise, it's a tag and the NFC core is notified. Detection
      ends.
4 - The digital stacks sends an ATR_REQ command containing a randomly
    generated NFCID3 and the general bytes obtained from the LLCP layer
    of NFC core.

For NFC-F technology:
1 - The digital stack receives a SENSF_RES as the reply of the
    SENSF_REQ command.
2   - If B1 and B2 of NFCID2 are 0x01 and 0xFE respectively, the peer
      device is configured for NFC-DEP protocol. NFC core is notified
      through nfc_targets_found(). Execution continues at step 4.
3   - Otherwise it's a type 3 tag. NFC core is notified. Detection
      ends.
4 - The digital stacks sends an ATR_REQ command containing the NFC-F
    NFCID2 as NFCID3 and the general bytes obtained from the LLCP layer
    of NFC core.

For both technologies:
5 - The digital stacks receives the ATR_RES response containing the
    NFCID3 and the general bytes of the peer device.
6 - The digital stack notifies NFC core that the DEP link is up through
    nfc_dep_link_up().
7 - The NFC core performs data exchange through tm_transceive().
8 - The digital stack sends a DEP_REQ command containing an I PDU with
    the data from NFC core.
9 - The digital stack receives a DEP_RES command
10  - If the DEP_RES response contains a supervisor PDU with timeout
      extension request (RTOX) the digital stack sends a DEP_REQ
      command containing a supervisor PDU acknowledging the RTOX
      request. The execution continues at step 9.
11  - If the DEP_RES response contains an I PDU, the response data is
      passed back to NFC core through the response callback. The
      execution continues at step 8.

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2013-09-25 02:02:27 +02:00

382 lines
7.9 KiB
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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.
*
*/
#include "digital.h"
#define DIGITAL_NFC_DEP_FRAME_DIR_OUT 0xD4
#define DIGITAL_NFC_DEP_FRAME_DIR_IN 0xD5
#define DIGITAL_NFC_DEP_NFCA_SOD_SB 0xF0
#define DIGITAL_CMD_ATR_REQ 0x00
#define DIGITAL_CMD_ATR_RES 0x01
#define DIGITAL_CMD_PSL_REQ 0x04
#define DIGITAL_CMD_PSL_RES 0x05
#define DIGITAL_CMD_DEP_REQ 0x06
#define DIGITAL_CMD_DEP_RES 0x07
#define DIGITAL_ATR_REQ_MIN_SIZE 16
#define DIGITAL_ATR_REQ_MAX_SIZE 64
#define DIGITAL_NFCID3_LEN ((u8)8)
#define DIGITAL_LR_BITS_PAYLOAD_SIZE_254B 0x30
#define DIGITAL_GB_BIT 0x02
#define DIGITAL_NFC_DEP_PFB_TYPE(pfb) ((pfb) & 0xE0)
#define DIGITAL_NFC_DEP_PFB_TIMEOUT_BIT 0x10
#define DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb) \
((pfb) & DIGITAL_NFC_DEP_PFB_TIMEOUT_BIT)
#define DIGITAL_NFC_DEP_MI_BIT_SET(pfb) ((pfb) & 0x10)
#define DIGITAL_NFC_DEP_NAD_BIT_SET(pfb) ((pfb) & 0x08)
#define DIGITAL_NFC_DEP_DID_BIT_SET(pfb) ((pfb) & 0x04)
#define DIGITAL_NFC_DEP_PFB_PNI(pfb) ((pfb) & 0x03)
#define DIGITAL_NFC_DEP_PFB_I_PDU 0x00
#define DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU 0x40
#define DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU 0x80
struct digital_atr_req {
u8 dir;
u8 cmd;
u8 nfcid3[10];
u8 did;
u8 bs;
u8 br;
u8 pp;
u8 gb[0];
} __packed;
struct digital_atr_res {
u8 dir;
u8 cmd;
u8 nfcid3[10];
u8 did;
u8 bs;
u8 br;
u8 to;
u8 pp;
u8 gb[0];
} __packed;
struct digital_psl_req {
u8 dir;
u8 cmd;
u8 did;
u8 brs;
u8 fsl;
} __packed;
struct digital_psl_res {
u8 dir;
u8 cmd;
u8 did;
} __packed;
struct digital_dep_req_res {
u8 dir;
u8 cmd;
u8 pfb;
} __packed;
static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
struct sk_buff *resp);
static void digital_skb_push_dep_sod(struct nfc_digital_dev *ddev,
struct sk_buff *skb)
{
skb_push(skb, sizeof(u8));
skb->data[0] = skb->len;
if (ddev->curr_rf_tech == NFC_DIGITAL_RF_TECH_106A)
*skb_push(skb, sizeof(u8)) = DIGITAL_NFC_DEP_NFCA_SOD_SB;
}
static int digital_skb_pull_dep_sod(struct nfc_digital_dev *ddev,
struct sk_buff *skb)
{
u8 size;
if (skb->len < 2)
return -EIO;
if (ddev->curr_rf_tech == NFC_DIGITAL_RF_TECH_106A)
skb_pull(skb, sizeof(u8));
size = skb->data[0];
if (size != skb->len)
return -EIO;
skb_pull(skb, sizeof(u8));
return 0;
}
static void digital_in_recv_atr_res(struct nfc_digital_dev *ddev, void *arg,
struct sk_buff *resp)
{
struct nfc_target *target = arg;
struct digital_atr_res *atr_res;
u8 gb_len;
int rc;
if (IS_ERR(resp)) {
rc = PTR_ERR(resp);
resp = NULL;
goto exit;
}
rc = ddev->skb_check_crc(resp);
if (rc) {
PROTOCOL_ERR("14.4.1.6");
goto exit;
}
rc = digital_skb_pull_dep_sod(ddev, resp);
if (rc) {
PROTOCOL_ERR("14.4.1.2");
goto exit;
}
if (resp->len < sizeof(struct digital_atr_res)) {
rc = -EIO;
goto exit;
}
gb_len = resp->len - sizeof(struct digital_atr_res);
atr_res = (struct digital_atr_res *)resp->data;
rc = nfc_set_remote_general_bytes(ddev->nfc_dev, atr_res->gb, gb_len);
if (rc)
goto exit;
rc = nfc_dep_link_is_up(ddev->nfc_dev, target->idx, NFC_COMM_ACTIVE,
NFC_RF_INITIATOR);
ddev->curr_nfc_dep_pni = 0;
exit:
dev_kfree_skb(resp);
if (rc)
ddev->curr_protocol = 0;
}
int digital_in_send_atr_req(struct nfc_digital_dev *ddev,
struct nfc_target *target, __u8 comm_mode, __u8 *gb,
size_t gb_len)
{
struct sk_buff *skb;
struct digital_atr_req *atr_req;
uint size;
size = DIGITAL_ATR_REQ_MIN_SIZE + gb_len;
if (size > DIGITAL_ATR_REQ_MAX_SIZE) {
PROTOCOL_ERR("14.6.1.1");
return -EINVAL;
}
skb = digital_skb_alloc(ddev, size);
if (!skb)
return -ENOMEM;
skb_put(skb, sizeof(struct digital_atr_req));
atr_req = (struct digital_atr_req *)skb->data;
memset(atr_req, 0, sizeof(struct digital_atr_req));
atr_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
atr_req->cmd = DIGITAL_CMD_ATR_REQ;
if (target->nfcid2_len)
memcpy(atr_req->nfcid3, target->nfcid2,
max(target->nfcid2_len, DIGITAL_NFCID3_LEN));
else
get_random_bytes(atr_req->nfcid3, DIGITAL_NFCID3_LEN);
atr_req->did = 0;
atr_req->bs = 0;
atr_req->br = 0;
atr_req->pp = DIGITAL_LR_BITS_PAYLOAD_SIZE_254B;
if (gb_len) {
atr_req->pp |= DIGITAL_GB_BIT;
memcpy(skb_put(skb, gb_len), gb, gb_len);
}
digital_skb_push_dep_sod(ddev, skb);
ddev->skb_add_crc(skb);
digital_in_send_cmd(ddev, skb, 500, digital_in_recv_atr_res, target);
return 0;
}
static int digital_in_send_rtox(struct nfc_digital_dev *ddev,
struct digital_data_exch *data_exch, u8 rtox)
{
struct digital_dep_req_res *dep_req;
struct sk_buff *skb;
int rc;
skb = digital_skb_alloc(ddev, 1);
if (!skb)
return -ENOMEM;
*skb_put(skb, 1) = rtox;
skb_push(skb, sizeof(struct digital_dep_req_res));
dep_req = (struct digital_dep_req_res *)skb->data;
dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
dep_req->cmd = DIGITAL_CMD_DEP_REQ;
dep_req->pfb = DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU |
DIGITAL_NFC_DEP_PFB_TIMEOUT_BIT;
digital_skb_push_dep_sod(ddev, skb);
ddev->skb_add_crc(skb);
rc = digital_in_send_cmd(ddev, skb, 1500, digital_in_recv_dep_res,
data_exch);
return rc;
}
static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
struct sk_buff *resp)
{
struct digital_data_exch *data_exch = arg;
struct digital_dep_req_res *dep_res;
u8 pfb;
uint size;
int rc;
if (IS_ERR(resp)) {
rc = PTR_ERR(resp);
resp = NULL;
goto exit;
}
rc = ddev->skb_check_crc(resp);
if (rc) {
PROTOCOL_ERR("14.4.1.6");
goto error;
}
rc = digital_skb_pull_dep_sod(ddev, resp);
if (rc) {
PROTOCOL_ERR("14.4.1.2");
goto exit;
}
dep_res = (struct digital_dep_req_res *)resp->data;
if (resp->len < sizeof(struct digital_dep_req_res) ||
dep_res->dir != DIGITAL_NFC_DEP_FRAME_DIR_IN ||
dep_res->cmd != DIGITAL_CMD_DEP_RES) {
rc = -EIO;
goto error;
}
pfb = dep_res->pfb;
switch (DIGITAL_NFC_DEP_PFB_TYPE(pfb)) {
case DIGITAL_NFC_DEP_PFB_I_PDU:
if (DIGITAL_NFC_DEP_PFB_PNI(pfb) != ddev->curr_nfc_dep_pni) {
PROTOCOL_ERR("14.12.3.3");
rc = -EIO;
goto error;
}
ddev->curr_nfc_dep_pni =
DIGITAL_NFC_DEP_PFB_PNI(ddev->curr_nfc_dep_pni + 1);
rc = 0;
break;
case DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU:
PR_ERR("Received a ACK/NACK PDU");
rc = -EIO;
goto error;
case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:
if (!DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb)) {
rc = -EINVAL;
goto error;
}
rc = digital_in_send_rtox(ddev, data_exch, resp->data[3]);
if (rc)
goto error;
kfree_skb(resp);
return;
}
if (DIGITAL_NFC_DEP_MI_BIT_SET(pfb)) {
PR_ERR("MI bit set. Chained PDU not supported.");
rc = -EIO;
goto error;
}
size = sizeof(struct digital_dep_req_res);
if (DIGITAL_NFC_DEP_DID_BIT_SET(pfb))
size++;
if (size > resp->len) {
rc = -EIO;
goto error;
}
skb_pull(resp, size);
exit:
data_exch->cb(data_exch->cb_context, resp, rc);
error:
kfree(data_exch);
if (rc)
kfree_skb(resp);
}
int digital_in_send_dep_req(struct nfc_digital_dev *ddev,
struct nfc_target *target, struct sk_buff *skb,
struct digital_data_exch *data_exch)
{
struct digital_dep_req_res *dep_req;
skb_push(skb, sizeof(struct digital_dep_req_res));
dep_req = (struct digital_dep_req_res *)skb->data;
dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
dep_req->cmd = DIGITAL_CMD_DEP_REQ;
dep_req->pfb = ddev->curr_nfc_dep_pni;
digital_skb_push_dep_sod(ddev, skb);
ddev->skb_add_crc(skb);
return digital_in_send_cmd(ddev, skb, 1500, digital_in_recv_dep_res,
data_exch);
}
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