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>

1 files changed, 381 insertions, 0 deletions

diff --git a/net/nfc/digital_dep.c b/net/nfc/digital_dep.c
new file mode 100644
index 00000000000..be984c4204d
--- /dev/null
+++ b/net/nfc/digital_dep.c
@@ -0,0 +1,381 @@
+/*
+ * 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);
+}