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1/*
2 * HCI based Driver for Inside Secure microread NFC Chip - i2c layer
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, see <http://www.gnu.org/licenses/>.
17 */
18
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/module.h>
22#include <linux/i2c.h>
23#include <linux/delay.h>
24#include <linux/slab.h>
25#include <linux/interrupt.h>
26#include <linux/gpio.h>
27
28#include <linux/nfc.h>
29#include <net/nfc/hci.h>
30#include <net/nfc/llc.h>
31
32#include "microread.h"
33
34#define MICROREAD_I2C_DRIVER_NAME "microread"
35
36#define MICROREAD_I2C_FRAME_HEADROOM 1
37#define MICROREAD_I2C_FRAME_TAILROOM 1
38
39/* framing in HCI mode */
40#define MICROREAD_I2C_LLC_LEN 1
41#define MICROREAD_I2C_LLC_CRC 1
42#define MICROREAD_I2C_LLC_LEN_CRC (MICROREAD_I2C_LLC_LEN + \
43 MICROREAD_I2C_LLC_CRC)
44#define MICROREAD_I2C_LLC_MIN_SIZE (1 + MICROREAD_I2C_LLC_LEN_CRC)
45#define MICROREAD_I2C_LLC_MAX_PAYLOAD 29
46#define MICROREAD_I2C_LLC_MAX_SIZE (MICROREAD_I2C_LLC_LEN_CRC + 1 + \
47 MICROREAD_I2C_LLC_MAX_PAYLOAD)
48
49struct microread_i2c_phy {
50 struct i2c_client *i2c_dev;
51 struct nfc_hci_dev *hdev;
52
53 int irq;
54
55 int hard_fault; /*
56 * < 0 if hardware error occured (e.g. i2c err)
57 * and prevents normal operation.
58 */
59};
60
61#define I2C_DUMP_SKB(info, skb) \
62do { \
63 pr_debug("%s:\n", info); \
64 print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \
65 16, 1, (skb)->data, (skb)->len, 0); \
66} while (0)
67
68static void microread_i2c_add_len_crc(struct sk_buff *skb)
69{
70 int i;
71 u8 crc = 0;
72 int len;
73
74 len = skb->len;
75 *skb_push(skb, 1) = len;
76
77 for (i = 0; i < skb->len; i++)
78 crc = crc ^ skb->data[i];
79
80 *skb_put(skb, 1) = crc;
81}
82
83static void microread_i2c_remove_len_crc(struct sk_buff *skb)
84{
85 skb_pull(skb, MICROREAD_I2C_FRAME_HEADROOM);
86 skb_trim(skb, MICROREAD_I2C_FRAME_TAILROOM);
87}
88
89static int check_crc(struct sk_buff *skb)
90{
91 int i;
92 u8 crc = 0;
93
94 for (i = 0; i < skb->len - 1; i++)
95 crc = crc ^ skb->data[i];
96
97 if (crc != skb->data[skb->len-1]) {
98 pr_err("CRC error 0x%x != 0x%x\n", crc, skb->data[skb->len-1]);
99 pr_info("%s: BAD CRC\n", __func__);
100 return -EPERM;
101 }
102
103 return 0;
104}
105
106static int microread_i2c_enable(void *phy_id)
107{
108 return 0;
109}
110
111static void microread_i2c_disable(void *phy_id)
112{
113 return;
114}
115
116static int microread_i2c_write(void *phy_id, struct sk_buff *skb)
117{
118 int r;
119 struct microread_i2c_phy *phy = phy_id;
120 struct i2c_client *client = phy->i2c_dev;
121
122 if (phy->hard_fault != 0)
123 return phy->hard_fault;
124
125 usleep_range(3000, 6000);
126
127 microread_i2c_add_len_crc(skb);
128
129 I2C_DUMP_SKB("i2c frame written", skb);
130
131 r = i2c_master_send(client, skb->data, skb->len);
132
133 if (r == -EREMOTEIO) { /* Retry, chip was in standby */
134 usleep_range(6000, 10000);
135 r = i2c_master_send(client, skb->data, skb->len);
136 }
137
138 if (r >= 0) {
139 if (r != skb->len)
140 r = -EREMOTEIO;
141 else
142 r = 0;
143 }
144
145 microread_i2c_remove_len_crc(skb);
146
147 return r;
148}
149
150
151static int microread_i2c_read(struct microread_i2c_phy *phy,
152 struct sk_buff **skb)
153{
154 int r;
155 u8 len;
156 u8 tmp[MICROREAD_I2C_LLC_MAX_SIZE - 1];
157 struct i2c_client *client = phy->i2c_dev;
158
159 r = i2c_master_recv(client, &len, 1);
160 if (r != 1) {
161 nfc_err(&client->dev, "cannot read len byte\n");
162 return -EREMOTEIO;
163 }
164
165 if ((len < MICROREAD_I2C_LLC_MIN_SIZE) ||
166 (len > MICROREAD_I2C_LLC_MAX_SIZE)) {
167 nfc_err(&client->dev, "invalid len byte\n");
168 r = -EBADMSG;
169 goto flush;
170 }
171
172 *skb = alloc_skb(1 + len, GFP_KERNEL);
173 if (*skb == NULL) {
174 r = -ENOMEM;
175 goto flush;
176 }
177
178 *skb_put(*skb, 1) = len;
179
180 r = i2c_master_recv(client, skb_put(*skb, len), len);
181 if (r != len) {
182 kfree_skb(*skb);
183 return -EREMOTEIO;
184 }
185
186 I2C_DUMP_SKB("cc frame read", *skb);
187
188 r = check_crc(*skb);
189 if (r != 0) {
190 kfree_skb(*skb);
191 r = -EBADMSG;
192 goto flush;
193 }
194
195 skb_pull(*skb, 1);
196 skb_trim(*skb, (*skb)->len - MICROREAD_I2C_FRAME_TAILROOM);
197
198 usleep_range(3000, 6000);
199
200 return 0;
201
202flush:
203 if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
204 r = -EREMOTEIO;
205
206 usleep_range(3000, 6000);
207
208 return r;
209}
210
211static irqreturn_t microread_i2c_irq_thread_fn(int irq, void *phy_id)
212{
213 struct microread_i2c_phy *phy = phy_id;
214 struct i2c_client *client;
215 struct sk_buff *skb = NULL;
216 int r;
217
218 if (!phy || irq != phy->i2c_dev->irq) {
219 WARN_ON_ONCE(1);
220 return IRQ_NONE;
221 }
222
223 client = phy->i2c_dev;
224
225 if (phy->hard_fault != 0)
226 return IRQ_HANDLED;
227
228 r = microread_i2c_read(phy, &skb);
229 if (r == -EREMOTEIO) {
230 phy->hard_fault = r;
231
232 nfc_hci_recv_frame(phy->hdev, NULL);
233
234 return IRQ_HANDLED;
235 } else if ((r == -ENOMEM) || (r == -EBADMSG)) {
236 return IRQ_HANDLED;
237 }
238
239 nfc_hci_recv_frame(phy->hdev, skb);
240
241 return IRQ_HANDLED;
242}
243
244static struct nfc_phy_ops i2c_phy_ops = {
245 .write = microread_i2c_write,
246 .enable = microread_i2c_enable,
247 .disable = microread_i2c_disable,
248};
249
250static int microread_i2c_probe(struct i2c_client *client,
251 const struct i2c_device_id *id)
252{
253 struct microread_i2c_phy *phy;
254 struct microread_nfc_platform_data *pdata =
255 dev_get_platdata(&client->dev);
256 int r;
257
258 dev_dbg(&client->dev, "client %p\n", client);
259
260 if (!pdata) {
261 nfc_err(&client->dev, "client %p: missing platform data\n",
262 client);
263 return -EINVAL;
264 }
265
266 phy = devm_kzalloc(&client->dev, sizeof(struct microread_i2c_phy),
267 GFP_KERNEL);
268 if (!phy)
269 return -ENOMEM;
270
271 i2c_set_clientdata(client, phy);
272 phy->i2c_dev = client;
273
274 r = request_threaded_irq(client->irq, NULL, microread_i2c_irq_thread_fn,
275 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
276 MICROREAD_I2C_DRIVER_NAME, phy);
277 if (r) {
278 nfc_err(&client->dev, "Unable to register IRQ handler\n");
279 return r;
280 }
281
282 r = microread_probe(phy, &i2c_phy_ops, LLC_SHDLC_NAME,
283 MICROREAD_I2C_FRAME_HEADROOM,
284 MICROREAD_I2C_FRAME_TAILROOM,
285 MICROREAD_I2C_LLC_MAX_PAYLOAD, &phy->hdev);
286 if (r < 0)
287 goto err_irq;
288
289 nfc_info(&client->dev, "Probed");
290
291 return 0;
292
293err_irq:
294 free_irq(client->irq, phy);
295
296 return r;
297}
298
299static int microread_i2c_remove(struct i2c_client *client)
300{
301 struct microread_i2c_phy *phy = i2c_get_clientdata(client);
302
303 microread_remove(phy->hdev);
304
305 free_irq(client->irq, phy);
306
307 return 0;
308}
309
310static struct i2c_device_id microread_i2c_id[] = {
311 { MICROREAD_I2C_DRIVER_NAME, 0},
312 { }
313};
314MODULE_DEVICE_TABLE(i2c, microread_i2c_id);
315
316static struct i2c_driver microread_i2c_driver = {
317 .driver = {
318 .name = MICROREAD_I2C_DRIVER_NAME,
319 },
320 .probe = microread_i2c_probe,
321 .remove = microread_i2c_remove,
322 .id_table = microread_i2c_id,
323};
324
325module_i2c_driver(microread_i2c_driver);
326
327MODULE_LICENSE("GPL");
328MODULE_DESCRIPTION(DRIVER_DESC);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * HCI based Driver for Inside Secure microread NFC Chip - i2c layer
4 *
5 * Copyright (C) 2013 Intel Corporation. All rights reserved.
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/module.h>
11#include <linux/i2c.h>
12#include <linux/delay.h>
13#include <linux/slab.h>
14#include <linux/interrupt.h>
15#include <linux/gpio.h>
16
17#include <linux/nfc.h>
18#include <net/nfc/hci.h>
19#include <net/nfc/llc.h>
20
21#include "microread.h"
22
23#define MICROREAD_I2C_DRIVER_NAME "microread"
24
25#define MICROREAD_I2C_FRAME_HEADROOM 1
26#define MICROREAD_I2C_FRAME_TAILROOM 1
27
28/* framing in HCI mode */
29#define MICROREAD_I2C_LLC_LEN 1
30#define MICROREAD_I2C_LLC_CRC 1
31#define MICROREAD_I2C_LLC_LEN_CRC (MICROREAD_I2C_LLC_LEN + \
32 MICROREAD_I2C_LLC_CRC)
33#define MICROREAD_I2C_LLC_MIN_SIZE (1 + MICROREAD_I2C_LLC_LEN_CRC)
34#define MICROREAD_I2C_LLC_MAX_PAYLOAD 29
35#define MICROREAD_I2C_LLC_MAX_SIZE (MICROREAD_I2C_LLC_LEN_CRC + 1 + \
36 MICROREAD_I2C_LLC_MAX_PAYLOAD)
37
38struct microread_i2c_phy {
39 struct i2c_client *i2c_dev;
40 struct nfc_hci_dev *hdev;
41
42 int hard_fault; /*
43 * < 0 if hardware error occured (e.g. i2c err)
44 * and prevents normal operation.
45 */
46};
47
48#define I2C_DUMP_SKB(info, skb) \
49do { \
50 pr_debug("%s:\n", info); \
51 print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \
52 16, 1, (skb)->data, (skb)->len, 0); \
53} while (0)
54
55static void microread_i2c_add_len_crc(struct sk_buff *skb)
56{
57 int i;
58 u8 crc = 0;
59 int len;
60
61 len = skb->len;
62 *(u8 *)skb_push(skb, 1) = len;
63
64 for (i = 0; i < skb->len; i++)
65 crc = crc ^ skb->data[i];
66
67 skb_put_u8(skb, crc);
68}
69
70static void microread_i2c_remove_len_crc(struct sk_buff *skb)
71{
72 skb_pull(skb, MICROREAD_I2C_FRAME_HEADROOM);
73 skb_trim(skb, MICROREAD_I2C_FRAME_TAILROOM);
74}
75
76static int check_crc(const struct sk_buff *skb)
77{
78 int i;
79 u8 crc = 0;
80
81 for (i = 0; i < skb->len - 1; i++)
82 crc = crc ^ skb->data[i];
83
84 if (crc != skb->data[skb->len-1]) {
85 pr_err("CRC error 0x%x != 0x%x\n", crc, skb->data[skb->len-1]);
86 pr_info("%s: BAD CRC\n", __func__);
87 return -EPERM;
88 }
89
90 return 0;
91}
92
93static int microread_i2c_enable(void *phy_id)
94{
95 return 0;
96}
97
98static void microread_i2c_disable(void *phy_id)
99{
100 return;
101}
102
103static int microread_i2c_write(void *phy_id, struct sk_buff *skb)
104{
105 int r;
106 struct microread_i2c_phy *phy = phy_id;
107 struct i2c_client *client = phy->i2c_dev;
108
109 if (phy->hard_fault != 0)
110 return phy->hard_fault;
111
112 usleep_range(3000, 6000);
113
114 microread_i2c_add_len_crc(skb);
115
116 I2C_DUMP_SKB("i2c frame written", skb);
117
118 r = i2c_master_send(client, skb->data, skb->len);
119
120 if (r == -EREMOTEIO) { /* Retry, chip was in standby */
121 usleep_range(6000, 10000);
122 r = i2c_master_send(client, skb->data, skb->len);
123 }
124
125 if (r >= 0) {
126 if (r != skb->len)
127 r = -EREMOTEIO;
128 else
129 r = 0;
130 }
131
132 microread_i2c_remove_len_crc(skb);
133
134 return r;
135}
136
137
138static int microread_i2c_read(struct microread_i2c_phy *phy,
139 struct sk_buff **skb)
140{
141 int r;
142 u8 len;
143 u8 tmp[MICROREAD_I2C_LLC_MAX_SIZE - 1];
144 struct i2c_client *client = phy->i2c_dev;
145
146 r = i2c_master_recv(client, &len, 1);
147 if (r != 1) {
148 nfc_err(&client->dev, "cannot read len byte\n");
149 return -EREMOTEIO;
150 }
151
152 if ((len < MICROREAD_I2C_LLC_MIN_SIZE) ||
153 (len > MICROREAD_I2C_LLC_MAX_SIZE)) {
154 nfc_err(&client->dev, "invalid len byte\n");
155 r = -EBADMSG;
156 goto flush;
157 }
158
159 *skb = alloc_skb(1 + len, GFP_KERNEL);
160 if (*skb == NULL) {
161 r = -ENOMEM;
162 goto flush;
163 }
164
165 skb_put_u8(*skb, len);
166
167 r = i2c_master_recv(client, skb_put(*skb, len), len);
168 if (r != len) {
169 kfree_skb(*skb);
170 return -EREMOTEIO;
171 }
172
173 I2C_DUMP_SKB("cc frame read", *skb);
174
175 r = check_crc(*skb);
176 if (r != 0) {
177 kfree_skb(*skb);
178 r = -EBADMSG;
179 goto flush;
180 }
181
182 skb_pull(*skb, 1);
183 skb_trim(*skb, (*skb)->len - MICROREAD_I2C_FRAME_TAILROOM);
184
185 usleep_range(3000, 6000);
186
187 return 0;
188
189flush:
190 if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
191 r = -EREMOTEIO;
192
193 usleep_range(3000, 6000);
194
195 return r;
196}
197
198static irqreturn_t microread_i2c_irq_thread_fn(int irq, void *phy_id)
199{
200 struct microread_i2c_phy *phy = phy_id;
201 struct sk_buff *skb = NULL;
202 int r;
203
204 if (!phy || irq != phy->i2c_dev->irq) {
205 WARN_ON_ONCE(1);
206 return IRQ_NONE;
207 }
208
209 if (phy->hard_fault != 0)
210 return IRQ_HANDLED;
211
212 r = microread_i2c_read(phy, &skb);
213 if (r == -EREMOTEIO) {
214 phy->hard_fault = r;
215
216 nfc_hci_recv_frame(phy->hdev, NULL);
217
218 return IRQ_HANDLED;
219 } else if ((r == -ENOMEM) || (r == -EBADMSG)) {
220 return IRQ_HANDLED;
221 }
222
223 nfc_hci_recv_frame(phy->hdev, skb);
224
225 return IRQ_HANDLED;
226}
227
228static const struct nfc_phy_ops i2c_phy_ops = {
229 .write = microread_i2c_write,
230 .enable = microread_i2c_enable,
231 .disable = microread_i2c_disable,
232};
233
234static int microread_i2c_probe(struct i2c_client *client)
235{
236 struct microread_i2c_phy *phy;
237 int r;
238
239 phy = devm_kzalloc(&client->dev, sizeof(struct microread_i2c_phy),
240 GFP_KERNEL);
241 if (!phy)
242 return -ENOMEM;
243
244 i2c_set_clientdata(client, phy);
245 phy->i2c_dev = client;
246
247 r = request_threaded_irq(client->irq, NULL, microread_i2c_irq_thread_fn,
248 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
249 MICROREAD_I2C_DRIVER_NAME, phy);
250 if (r) {
251 nfc_err(&client->dev, "Unable to register IRQ handler\n");
252 return r;
253 }
254
255 r = microread_probe(phy, &i2c_phy_ops, LLC_SHDLC_NAME,
256 MICROREAD_I2C_FRAME_HEADROOM,
257 MICROREAD_I2C_FRAME_TAILROOM,
258 MICROREAD_I2C_LLC_MAX_PAYLOAD, &phy->hdev);
259 if (r < 0)
260 goto err_irq;
261
262 return 0;
263
264err_irq:
265 free_irq(client->irq, phy);
266
267 return r;
268}
269
270static void microread_i2c_remove(struct i2c_client *client)
271{
272 struct microread_i2c_phy *phy = i2c_get_clientdata(client);
273
274 microread_remove(phy->hdev);
275
276 free_irq(client->irq, phy);
277}
278
279static const struct i2c_device_id microread_i2c_id[] = {
280 { MICROREAD_I2C_DRIVER_NAME },
281 { }
282};
283MODULE_DEVICE_TABLE(i2c, microread_i2c_id);
284
285static struct i2c_driver microread_i2c_driver = {
286 .driver = {
287 .name = MICROREAD_I2C_DRIVER_NAME,
288 },
289 .probe = microread_i2c_probe,
290 .remove = microread_i2c_remove,
291 .id_table = microread_i2c_id,
292};
293
294module_i2c_driver(microread_i2c_driver);
295
296MODULE_LICENSE("GPL");
297MODULE_DESCRIPTION(DRIVER_DESC);