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e0af11fa SO |
1 | /* |
2 | * HCI based Driver for Inside Secure microread NFC Chip | |
3 | * | |
4 | * Copyright (C) 2013 Intel Corporation. All rights reserved. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms and conditions of the GNU General Public License, | |
8 | * version 2, as published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the | |
17 | * Free Software Foundation, Inc., | |
18 | * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
19 | */ | |
20 | ||
21 | #include <linux/module.h> | |
22 | #include <linux/slab.h> | |
23 | #include <linux/interrupt.h> | |
24 | #include <linux/gpio.h> | |
25 | #include <linux/mei_bus.h> | |
26 | ||
27 | #include <linux/nfc.h> | |
28 | #include <net/nfc/hci.h> | |
29 | #include <net/nfc/llc.h> | |
30 | ||
31 | #include "microread.h" | |
32 | ||
33 | #define MICROREAD_DRIVER_NAME "microread" | |
34 | ||
35 | #define MICROREAD_UUID UUID_LE(0x0bb17a78, 0x2a8e, 0x4c50, 0x94, \ | |
36 | 0xd4, 0x50, 0x26, 0x67, 0x23, 0x77, 0x5c) | |
37 | ||
38 | struct mei_nfc_hdr { | |
39 | u8 cmd; | |
40 | u8 status; | |
41 | u16 req_id; | |
42 | u32 reserved; | |
43 | u16 data_size; | |
44 | } __attribute__((packed)); | |
45 | ||
46 | #define MEI_NFC_HEADER_SIZE 10 | |
47 | #define MEI_NFC_MAX_HCI_PAYLOAD 300 | |
48 | #define MEI_NFC_MAX_READ (MEI_NFC_HEADER_SIZE + MEI_NFC_MAX_HCI_PAYLOAD) | |
49 | ||
50 | struct microread_mei_phy { | |
51 | struct mei_bus_client *client; | |
52 | struct nfc_hci_dev *hdev; | |
53 | ||
54 | int powered; | |
55 | ||
56 | int hard_fault; /* | |
57 | * < 0 if hardware error occured (e.g. i2c err) | |
58 | * and prevents normal operation. | |
59 | */ | |
60 | }; | |
61 | ||
62 | #define MEI_DUMP_SKB_IN(info, skb) \ | |
63 | do { \ | |
64 | pr_debug("%s:\n", info); \ | |
65 | print_hex_dump(KERN_DEBUG, "mei in : ", DUMP_PREFIX_OFFSET, \ | |
66 | 16, 1, (skb)->data, (skb)->len, 0); \ | |
67 | } while (0) | |
68 | ||
69 | #define MEI_DUMP_SKB_OUT(info, skb) \ | |
70 | do { \ | |
71 | pr_debug("%s:\n", info); \ | |
72 | print_hex_dump(KERN_DEBUG, "mei out: ", DUMP_PREFIX_OFFSET, \ | |
73 | 16, 1, (skb)->data, (skb)->len, 0); \ | |
74 | } while (0) | |
75 | ||
76 | static int microread_mei_enable(void *phy_id) | |
77 | { | |
78 | struct microread_mei_phy *phy = phy_id; | |
79 | ||
80 | pr_info(DRIVER_DESC ": %s\n", __func__); | |
81 | ||
82 | phy->powered = 1; | |
83 | ||
84 | return 0; | |
85 | } | |
86 | ||
87 | static void microread_mei_disable(void *phy_id) | |
88 | { | |
89 | struct microread_mei_phy *phy = phy_id; | |
90 | ||
91 | pr_info(DRIVER_DESC ": %s\n", __func__); | |
92 | ||
93 | phy->powered = 0; | |
94 | } | |
95 | ||
96 | /* | |
97 | * Writing a frame must not return the number of written bytes. | |
98 | * It must return either zero for success, or <0 for error. | |
99 | * In addition, it must not alter the skb | |
100 | */ | |
101 | static int microread_mei_write(void *phy_id, struct sk_buff *skb) | |
102 | { | |
103 | struct microread_mei_phy *phy = phy_id; | |
104 | int r; | |
105 | ||
106 | MEI_DUMP_SKB_OUT("mei frame sent", skb); | |
107 | ||
108 | r = mei_bus_send(phy->client, skb->data, skb->len); | |
109 | if (r > 0) | |
110 | r = 0; | |
111 | ||
112 | return r; | |
113 | } | |
114 | ||
115 | static void microread_event_cb(struct mei_bus_client *client, u32 events, | |
116 | void *context) | |
117 | { | |
118 | struct microread_mei_phy *phy = context; | |
119 | ||
120 | if (phy->hard_fault != 0) | |
121 | return; | |
122 | ||
123 | if (events & BIT(MEI_BUS_EVENT_RX)) { | |
124 | struct sk_buff *skb; | |
125 | int reply_size; | |
126 | ||
127 | skb = alloc_skb(MEI_NFC_MAX_READ, GFP_KERNEL); | |
128 | if (!skb) | |
129 | return; | |
130 | ||
131 | reply_size = mei_bus_recv(client, skb->data, MEI_NFC_MAX_READ); | |
132 | if (reply_size < MEI_NFC_HEADER_SIZE) { | |
133 | kfree(skb); | |
134 | return; | |
135 | } | |
136 | ||
137 | skb_put(skb, reply_size); | |
138 | skb_pull(skb, MEI_NFC_HEADER_SIZE); | |
139 | ||
140 | MEI_DUMP_SKB_IN("mei frame read", skb); | |
141 | ||
142 | nfc_hci_recv_frame(phy->hdev, skb); | |
143 | } | |
144 | } | |
145 | ||
146 | static struct nfc_phy_ops mei_phy_ops = { | |
147 | .write = microread_mei_write, | |
148 | .enable = microread_mei_enable, | |
149 | .disable = microread_mei_disable, | |
150 | }; | |
151 | ||
152 | static int microread_mei_probe(struct mei_bus_client *client) | |
153 | { | |
154 | struct microread_mei_phy *phy; | |
155 | int r; | |
156 | ||
157 | pr_info("Probing NFC microread\n"); | |
158 | ||
159 | phy = kzalloc(sizeof(struct microread_mei_phy), GFP_KERNEL); | |
160 | if (!phy) { | |
161 | pr_err("Cannot allocate memory for microread mei phy.\n"); | |
162 | return -ENOMEM; | |
163 | } | |
164 | ||
165 | phy->client = client; | |
166 | mei_bus_set_clientdata(client, phy); | |
167 | ||
168 | r = mei_bus_register_event_cb(client, microread_event_cb, phy); | |
169 | if (r) { | |
170 | pr_err(MICROREAD_DRIVER_NAME ": event cb registration failed\n"); | |
171 | goto err_out; | |
172 | } | |
173 | ||
174 | r = microread_probe(phy, &mei_phy_ops, LLC_NOP_NAME, | |
175 | MEI_NFC_HEADER_SIZE, 0, MEI_NFC_MAX_HCI_PAYLOAD, | |
176 | &phy->hdev); | |
177 | if (r < 0) | |
178 | goto err_out; | |
179 | ||
180 | return 0; | |
181 | ||
182 | err_out: | |
183 | kfree(phy); | |
184 | ||
185 | return r; | |
186 | } | |
187 | ||
188 | static int microread_mei_remove(struct mei_bus_client *client) | |
189 | { | |
190 | struct microread_mei_phy *phy = mei_bus_get_clientdata(client); | |
191 | ||
192 | pr_info("Removing microread\n"); | |
193 | ||
194 | microread_remove(phy->hdev); | |
195 | ||
196 | if (phy->powered) | |
197 | microread_mei_disable(phy); | |
198 | ||
199 | kfree(phy); | |
200 | ||
201 | return 0; | |
202 | } | |
203 | ||
204 | static struct mei_bus_driver microread_driver = { | |
205 | .driver = { | |
206 | .name = MICROREAD_DRIVER_NAME, | |
207 | }, | |
208 | .id = { | |
209 | .name = MICROREAD_DRIVER_NAME, | |
210 | .uuid = MICROREAD_UUID, | |
211 | }, | |
212 | ||
213 | .probe = microread_mei_probe, | |
214 | .remove = microread_mei_remove, | |
215 | }; | |
216 | ||
217 | static int microread_mei_init(void) | |
218 | { | |
219 | int r; | |
220 | ||
221 | pr_debug(DRIVER_DESC ": %s\n", __func__); | |
222 | ||
223 | r = mei_driver_register(µread_driver); | |
224 | if (r) { | |
225 | pr_err(MICROREAD_DRIVER_NAME ": driver registration failed\n"); | |
226 | return r; | |
227 | } | |
228 | ||
229 | return 0; | |
230 | } | |
231 | ||
232 | static void microread_mei_exit(void) | |
233 | { | |
234 | mei_driver_unregister(µread_driver); | |
235 | } | |
236 | ||
237 | module_init(microread_mei_init); | |
238 | module_exit(microread_mei_exit); | |
239 | ||
240 | MODULE_LICENSE("GPL"); | |
241 | MODULE_DESCRIPTION(DRIVER_DESC); |