summaryrefslogtreecommitdiff
path: root/drivers/nfc/microread/mei.c
blob: c078e56d7d14bc77177a7060053e83d324875113 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
/*
 * HCI based Driver for Inside Secure microread NFC Chip
 *
 * Copyright (C) 2013  Intel Corporation. All rights reserved.
 *
 * 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 that 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the
 * Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/mei_bus.h>

#include <linux/nfc.h>
#include <net/nfc/hci.h>
#include <net/nfc/llc.h>

#include "microread.h"

#define MICROREAD_DRIVER_NAME "microread"

#define MICROREAD_UUID UUID_LE(0x0bb17a78, 0x2a8e, 0x4c50, 0x94, \
			       0xd4, 0x50, 0x26, 0x67, 0x23, 0x77, 0x5c)

struct mei_nfc_hdr {
	u8 cmd;
	u8 status;
	u16 req_id;
	u32 reserved;
	u16 data_size;
} __attribute__((packed));

#define MEI_NFC_HEADER_SIZE 10
#define MEI_NFC_MAX_HCI_PAYLOAD 300
#define MEI_NFC_MAX_READ (MEI_NFC_HEADER_SIZE + MEI_NFC_MAX_HCI_PAYLOAD)

struct microread_mei_phy {
	struct mei_bus_client *client;
	struct nfc_hci_dev *hdev;

	int powered;

	int hard_fault;		/*
				 * < 0 if hardware error occured (e.g. i2c err)
				 * and prevents normal operation.
				 */
};

#define MEI_DUMP_SKB_IN(info, skb)					\
do {								\
	pr_debug("%s:\n", info);				\
	print_hex_dump(KERN_DEBUG, "mei in : ", DUMP_PREFIX_OFFSET,	\
		       16, 1, (skb)->data, (skb)->len, 0);	\
} while (0)

#define MEI_DUMP_SKB_OUT(info, skb)					\
do {								\
	pr_debug("%s:\n", info);				\
	print_hex_dump(KERN_DEBUG, "mei out: ", DUMP_PREFIX_OFFSET,	\
		       16, 1, (skb)->data, (skb)->len, 0);	\
} while (0)

static int microread_mei_enable(void *phy_id)
{
	struct microread_mei_phy *phy = phy_id;

	pr_info(DRIVER_DESC ": %s\n", __func__);

	phy->powered = 1;

	return 0;
}

static void microread_mei_disable(void *phy_id)
{
	struct microread_mei_phy *phy = phy_id;

	pr_info(DRIVER_DESC ": %s\n", __func__);

	phy->powered = 0;
}

/*
 * Writing a frame must not return the number of written bytes.
 * It must return either zero for success, or <0 for error.
 * In addition, it must not alter the skb
 */
static int microread_mei_write(void *phy_id, struct sk_buff *skb)
{
	struct microread_mei_phy *phy = phy_id;
	int r;

	MEI_DUMP_SKB_OUT("mei frame sent", skb);

	r = mei_bus_send(phy->client, skb->data, skb->len);
	if (r > 0)
		r = 0;

	return r;
}

static void microread_event_cb(struct mei_bus_client *client, u32 events,
			       void *context)
{
	struct microread_mei_phy *phy = context;

	if (phy->hard_fault != 0)
		return;

	if (events & BIT(MEI_BUS_EVENT_RX)) {
		struct sk_buff *skb;
		int reply_size;

		skb = alloc_skb(MEI_NFC_MAX_READ, GFP_KERNEL);
		if (!skb)
			return;

		reply_size = mei_bus_recv(client, skb->data, MEI_NFC_MAX_READ);
		if (reply_size < MEI_NFC_HEADER_SIZE) {
			kfree(skb);
			return;
		}

		skb_put(skb, reply_size);
		skb_pull(skb, MEI_NFC_HEADER_SIZE);

		MEI_DUMP_SKB_IN("mei frame read", skb);

		nfc_hci_recv_frame(phy->hdev, skb);
	}
}

static struct nfc_phy_ops mei_phy_ops = {
	.write = microread_mei_write,
	.enable = microread_mei_enable,
	.disable = microread_mei_disable,
};

static int microread_mei_probe(struct mei_bus_client *client)
{
	struct microread_mei_phy *phy;
	int r;

	pr_info("Probing NFC microread\n");

	phy = kzalloc(sizeof(struct microread_mei_phy), GFP_KERNEL);
	if (!phy) {
		pr_err("Cannot allocate memory for microread mei phy.\n");
		return -ENOMEM;
	}

	phy->client = client;
	mei_bus_set_clientdata(client, phy);

	r = mei_bus_register_event_cb(client, microread_event_cb, phy);
	if (r) {
		pr_err(MICROREAD_DRIVER_NAME ": event cb registration failed\n");
		goto err_out;
	}

	r = microread_probe(phy, &mei_phy_ops, LLC_NOP_NAME,
			    MEI_NFC_HEADER_SIZE, 0, MEI_NFC_MAX_HCI_PAYLOAD,
			    &phy->hdev);
	if (r < 0)
		goto err_out;

	return 0;

err_out:
	kfree(phy);

	return r;
}

static int microread_mei_remove(struct mei_bus_client *client)
{
	struct microread_mei_phy *phy = mei_bus_get_clientdata(client);

	pr_info("Removing microread\n");

	microread_remove(phy->hdev);

	if (phy->powered)
		microread_mei_disable(phy);

	kfree(phy);

	return 0;
}

static struct mei_bus_driver microread_driver = {
	.driver = {
		   .name = MICROREAD_DRIVER_NAME,
		  },
	.id = {
		.name = MICROREAD_DRIVER_NAME,
		.uuid = MICROREAD_UUID,
	},

	.probe = microread_mei_probe,
	.remove = microread_mei_remove,
};

static int microread_mei_init(void)
{
	int r;

	pr_debug(DRIVER_DESC ": %s\n", __func__);

	r = mei_driver_register(&microread_driver);
	if (r) {
		pr_err(MICROREAD_DRIVER_NAME ": driver registration failed\n");
		return r;
	}

	return 0;
}

static void microread_mei_exit(void)
{
	mei_driver_unregister(&microread_driver);
}

module_init(microread_mei_init);
module_exit(microread_mei_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION(DRIVER_DESC);