1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2012  Intel Corporation. All rights reserved.
4  */
5 
6 #define pr_fmt(fmt) "hci: %s: " fmt, __func__
7 
8 #include <linux/init.h>
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 
12 #include <net/nfc/hci.h>
13 
14 #include "hci.h"
15 
16 /*
17  * Payload is the HCP message data only. Instruction will be prepended.
18  * Guarantees that cb will be called upon completion or timeout delay
19  * counted from the moment the cmd is sent to the transport.
20  */
nfc_hci_hcp_message_tx(struct nfc_hci_dev * hdev,u8 pipe,u8 type,u8 instruction,const u8 * payload,size_t payload_len,data_exchange_cb_t cb,void * cb_context,unsigned long completion_delay)21 int nfc_hci_hcp_message_tx(struct nfc_hci_dev *hdev, u8 pipe,
22 			   u8 type, u8 instruction,
23 			   const u8 *payload, size_t payload_len,
24 			   data_exchange_cb_t cb, void *cb_context,
25 			   unsigned long completion_delay)
26 {
27 	struct nfc_dev *ndev = hdev->ndev;
28 	struct hci_msg *cmd;
29 	const u8 *ptr = payload;
30 	int hci_len, err;
31 	bool firstfrag = true;
32 
33 	cmd = kzalloc(sizeof(struct hci_msg), GFP_KERNEL);
34 	if (cmd == NULL)
35 		return -ENOMEM;
36 
37 	INIT_LIST_HEAD(&cmd->msg_l);
38 	skb_queue_head_init(&cmd->msg_frags);
39 	cmd->wait_response = (type == NFC_HCI_HCP_COMMAND) ? true : false;
40 	cmd->cb = cb;
41 	cmd->cb_context = cb_context;
42 	cmd->completion_delay = completion_delay;
43 
44 	hci_len = payload_len + 1;
45 	while (hci_len > 0) {
46 		struct sk_buff *skb;
47 		int skb_len, data_link_len;
48 		struct hcp_packet *packet;
49 
50 		if (NFC_HCI_HCP_PACKET_HEADER_LEN + hci_len <=
51 		    hdev->max_data_link_payload)
52 			data_link_len = hci_len;
53 		else
54 			data_link_len = hdev->max_data_link_payload -
55 					NFC_HCI_HCP_PACKET_HEADER_LEN;
56 
57 		skb_len = ndev->tx_headroom + NFC_HCI_HCP_PACKET_HEADER_LEN +
58 			  data_link_len + ndev->tx_tailroom;
59 		hci_len -= data_link_len;
60 
61 		skb = alloc_skb(skb_len, GFP_KERNEL);
62 		if (skb == NULL) {
63 			err = -ENOMEM;
64 			goto out_skb_err;
65 		}
66 		skb_reserve(skb, ndev->tx_headroom);
67 
68 		skb_put(skb, NFC_HCI_HCP_PACKET_HEADER_LEN + data_link_len);
69 
70 		/* Only the last fragment will have the cb bit set to 1 */
71 		packet = (struct hcp_packet *)skb->data;
72 		packet->header = pipe;
73 		if (firstfrag) {
74 			firstfrag = false;
75 			packet->message.header = HCP_HEADER(type, instruction);
76 			if (ptr) {
77 				memcpy(packet->message.data, ptr,
78 				       data_link_len - 1);
79 				ptr += data_link_len - 1;
80 			}
81 		} else {
82 			memcpy(&packet->message, ptr, data_link_len);
83 			ptr += data_link_len;
84 		}
85 
86 		/* This is the last fragment, set the cb bit */
87 		if (hci_len == 0)
88 			packet->header |= ~NFC_HCI_FRAGMENT;
89 
90 		skb_queue_tail(&cmd->msg_frags, skb);
91 	}
92 
93 	mutex_lock(&hdev->msg_tx_mutex);
94 
95 	if (hdev->shutting_down) {
96 		err = -ESHUTDOWN;
97 		mutex_unlock(&hdev->msg_tx_mutex);
98 		goto out_skb_err;
99 	}
100 
101 	list_add_tail(&cmd->msg_l, &hdev->msg_tx_queue);
102 	mutex_unlock(&hdev->msg_tx_mutex);
103 
104 	schedule_work(&hdev->msg_tx_work);
105 
106 	return 0;
107 
108 out_skb_err:
109 	skb_queue_purge(&cmd->msg_frags);
110 	kfree(cmd);
111 
112 	return err;
113 }
114 
115 /*
116  * Receive hcp message for pipe, with type and cmd.
117  * skb contains optional message data only.
118  */
nfc_hci_hcp_message_rx(struct nfc_hci_dev * hdev,u8 pipe,u8 type,u8 instruction,struct sk_buff * skb)119 void nfc_hci_hcp_message_rx(struct nfc_hci_dev *hdev, u8 pipe, u8 type,
120 			    u8 instruction, struct sk_buff *skb)
121 {
122 	switch (type) {
123 	case NFC_HCI_HCP_RESPONSE:
124 		nfc_hci_resp_received(hdev, instruction, skb);
125 		break;
126 	case NFC_HCI_HCP_COMMAND:
127 		nfc_hci_cmd_received(hdev, pipe, instruction, skb);
128 		break;
129 	case NFC_HCI_HCP_EVENT:
130 		nfc_hci_event_received(hdev, pipe, instruction, skb);
131 		break;
132 	default:
133 		pr_err("UNKNOWN MSG Type %d, instruction=%d\n",
134 		       type, instruction);
135 		kfree_skb(skb);
136 		break;
137 	}
138 }
139