blob: 696e3467eccc33ab1ee97c6da2a4940c489ee086 [file] [log] [blame]
Samuel Ortiz71054c72012-12-18 14:56:15 +01001/*
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, write to the
17 * Free Software Foundation, Inc.,
18 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 */
20
Joe Perches17936b42013-04-05 12:27:39 -070021#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22
Samuel Ortiz71054c72012-12-18 14:56:15 +010023#include <linux/module.h>
24#include <linux/i2c.h>
25#include <linux/delay.h>
26#include <linux/slab.h>
27#include <linux/interrupt.h>
28#include <linux/gpio.h>
29
30#include <linux/nfc.h>
31#include <net/nfc/hci.h>
32#include <net/nfc/llc.h>
33
34#include "microread.h"
35
36#define MICROREAD_I2C_DRIVER_NAME "microread"
37
38#define MICROREAD_I2C_FRAME_HEADROOM 1
39#define MICROREAD_I2C_FRAME_TAILROOM 1
40
41/* framing in HCI mode */
42#define MICROREAD_I2C_LLC_LEN 1
43#define MICROREAD_I2C_LLC_CRC 1
44#define MICROREAD_I2C_LLC_LEN_CRC (MICROREAD_I2C_LLC_LEN + \
45 MICROREAD_I2C_LLC_CRC)
46#define MICROREAD_I2C_LLC_MIN_SIZE (1 + MICROREAD_I2C_LLC_LEN_CRC)
47#define MICROREAD_I2C_LLC_MAX_PAYLOAD 29
48#define MICROREAD_I2C_LLC_MAX_SIZE (MICROREAD_I2C_LLC_LEN_CRC + 1 + \
49 MICROREAD_I2C_LLC_MAX_PAYLOAD)
50
51struct microread_i2c_phy {
52 struct i2c_client *i2c_dev;
53 struct nfc_hci_dev *hdev;
54
55 int irq;
56
57 int hard_fault; /*
58 * < 0 if hardware error occured (e.g. i2c err)
59 * and prevents normal operation.
60 */
61};
62
63#define I2C_DUMP_SKB(info, skb) \
64do { \
65 pr_debug("%s:\n", info); \
66 print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \
67 16, 1, (skb)->data, (skb)->len, 0); \
68} while (0)
69
70static void microread_i2c_add_len_crc(struct sk_buff *skb)
71{
72 int i;
73 u8 crc = 0;
74 int len;
75
76 len = skb->len;
77 *skb_push(skb, 1) = len;
78
79 for (i = 0; i < skb->len; i++)
80 crc = crc ^ skb->data[i];
81
82 *skb_put(skb, 1) = crc;
83}
84
85static void microread_i2c_remove_len_crc(struct sk_buff *skb)
86{
87 skb_pull(skb, MICROREAD_I2C_FRAME_HEADROOM);
88 skb_trim(skb, MICROREAD_I2C_FRAME_TAILROOM);
89}
90
91static int check_crc(struct sk_buff *skb)
92{
93 int i;
94 u8 crc = 0;
95
96 for (i = 0; i < skb->len - 1; i++)
97 crc = crc ^ skb->data[i];
98
99 if (crc != skb->data[skb->len-1]) {
Joe Perches17936b42013-04-05 12:27:39 -0700100 pr_err("CRC error 0x%x != 0x%x\n", crc, skb->data[skb->len-1]);
101 pr_info("%s: BAD CRC\n", __func__);
Samuel Ortiz71054c72012-12-18 14:56:15 +0100102 return -EPERM;
103 }
104
105 return 0;
106}
107
108static int microread_i2c_enable(void *phy_id)
109{
110 return 0;
111}
112
113static void microread_i2c_disable(void *phy_id)
114{
115 return;
116}
117
118static int microread_i2c_write(void *phy_id, struct sk_buff *skb)
119{
120 int r;
121 struct microread_i2c_phy *phy = phy_id;
122 struct i2c_client *client = phy->i2c_dev;
123
124 if (phy->hard_fault != 0)
125 return phy->hard_fault;
126
127 usleep_range(3000, 6000);
128
129 microread_i2c_add_len_crc(skb);
130
131 I2C_DUMP_SKB("i2c frame written", skb);
132
133 r = i2c_master_send(client, skb->data, skb->len);
134
135 if (r == -EREMOTEIO) { /* Retry, chip was in standby */
136 usleep_range(6000, 10000);
137 r = i2c_master_send(client, skb->data, skb->len);
138 }
139
140 if (r >= 0) {
141 if (r != skb->len)
142 r = -EREMOTEIO;
143 else
144 r = 0;
145 }
146
147 microread_i2c_remove_len_crc(skb);
148
149 return r;
150}
151
152
153static int microread_i2c_read(struct microread_i2c_phy *phy,
154 struct sk_buff **skb)
155{
156 int r;
157 u8 len;
158 u8 tmp[MICROREAD_I2C_LLC_MAX_SIZE - 1];
159 struct i2c_client *client = phy->i2c_dev;
160
Samuel Ortiz71054c72012-12-18 14:56:15 +0100161 r = i2c_master_recv(client, &len, 1);
162 if (r != 1) {
Joe Perches17936b42013-04-05 12:27:39 -0700163 nfc_err(&client->dev, "cannot read len byte\n");
Samuel Ortiz71054c72012-12-18 14:56:15 +0100164 return -EREMOTEIO;
165 }
166
167 if ((len < MICROREAD_I2C_LLC_MIN_SIZE) ||
168 (len > MICROREAD_I2C_LLC_MAX_SIZE)) {
Joe Perches17936b42013-04-05 12:27:39 -0700169 nfc_err(&client->dev, "invalid len byte\n");
Samuel Ortiz71054c72012-12-18 14:56:15 +0100170 r = -EBADMSG;
171 goto flush;
172 }
173
174 *skb = alloc_skb(1 + len, GFP_KERNEL);
175 if (*skb == NULL) {
176 r = -ENOMEM;
177 goto flush;
178 }
179
180 *skb_put(*skb, 1) = len;
181
182 r = i2c_master_recv(client, skb_put(*skb, len), len);
183 if (r != len) {
184 kfree_skb(*skb);
185 return -EREMOTEIO;
186 }
187
188 I2C_DUMP_SKB("cc frame read", *skb);
189
190 r = check_crc(*skb);
191 if (r != 0) {
192 kfree_skb(*skb);
193 r = -EBADMSG;
194 goto flush;
195 }
196
197 skb_pull(*skb, 1);
198 skb_trim(*skb, (*skb)->len - MICROREAD_I2C_FRAME_TAILROOM);
199
200 usleep_range(3000, 6000);
201
202 return 0;
203
204flush:
205 if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
206 r = -EREMOTEIO;
207
208 usleep_range(3000, 6000);
209
210 return r;
211}
212
213static irqreturn_t microread_i2c_irq_thread_fn(int irq, void *phy_id)
214{
215 struct microread_i2c_phy *phy = phy_id;
216 struct i2c_client *client;
217 struct sk_buff *skb = NULL;
218 int r;
219
220 if (!phy || irq != phy->i2c_dev->irq) {
221 WARN_ON_ONCE(1);
222 return IRQ_NONE;
223 }
224
225 client = phy->i2c_dev;
Samuel Ortiz71054c72012-12-18 14:56:15 +0100226
227 if (phy->hard_fault != 0)
228 return IRQ_HANDLED;
229
230 r = microread_i2c_read(phy, &skb);
231 if (r == -EREMOTEIO) {
232 phy->hard_fault = r;
233
234 nfc_hci_recv_frame(phy->hdev, NULL);
235
236 return IRQ_HANDLED;
237 } else if ((r == -ENOMEM) || (r == -EBADMSG)) {
238 return IRQ_HANDLED;
239 }
240
241 nfc_hci_recv_frame(phy->hdev, skb);
242
243 return IRQ_HANDLED;
244}
245
246static struct nfc_phy_ops i2c_phy_ops = {
247 .write = microread_i2c_write,
248 .enable = microread_i2c_enable,
249 .disable = microread_i2c_disable,
250};
251
252static int microread_i2c_probe(struct i2c_client *client,
253 const struct i2c_device_id *id)
254{
255 struct microread_i2c_phy *phy;
256 struct microread_nfc_platform_data *pdata =
257 dev_get_platdata(&client->dev);
258 int r;
259
Joe Perches17936b42013-04-05 12:27:39 -0700260 dev_dbg(&client->dev, "client %p\n", client);
Samuel Ortiz71054c72012-12-18 14:56:15 +0100261
262 if (!pdata) {
Joe Perches17936b42013-04-05 12:27:39 -0700263 nfc_err(&client->dev, "client %p: missing platform data\n",
Samuel Ortiz71054c72012-12-18 14:56:15 +0100264 client);
265 return -EINVAL;
266 }
267
268 phy = devm_kzalloc(&client->dev, sizeof(struct microread_i2c_phy),
269 GFP_KERNEL);
Joe Perches17936b42013-04-05 12:27:39 -0700270 if (!phy)
Samuel Ortiz71054c72012-12-18 14:56:15 +0100271 return -ENOMEM;
Samuel Ortiz71054c72012-12-18 14:56:15 +0100272
273 i2c_set_clientdata(client, phy);
274 phy->i2c_dev = client;
275
276 r = request_threaded_irq(client->irq, NULL, microread_i2c_irq_thread_fn,
277 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
278 MICROREAD_I2C_DRIVER_NAME, phy);
279 if (r) {
Joe Perches17936b42013-04-05 12:27:39 -0700280 nfc_err(&client->dev, "Unable to register IRQ handler\n");
Samuel Ortiz71054c72012-12-18 14:56:15 +0100281 return r;
282 }
283
284 r = microread_probe(phy, &i2c_phy_ops, LLC_SHDLC_NAME,
285 MICROREAD_I2C_FRAME_HEADROOM,
286 MICROREAD_I2C_FRAME_TAILROOM,
287 MICROREAD_I2C_LLC_MAX_PAYLOAD, &phy->hdev);
288 if (r < 0)
289 goto err_irq;
290
Joe Perches17936b42013-04-05 12:27:39 -0700291 nfc_info(&client->dev, "Probed");
Samuel Ortiz71054c72012-12-18 14:56:15 +0100292
293 return 0;
294
295err_irq:
296 free_irq(client->irq, phy);
297
298 return r;
299}
300
301static int microread_i2c_remove(struct i2c_client *client)
302{
303 struct microread_i2c_phy *phy = i2c_get_clientdata(client);
304
Samuel Ortiz71054c72012-12-18 14:56:15 +0100305 microread_remove(phy->hdev);
306
307 free_irq(client->irq, phy);
308
309 return 0;
310}
311
312static struct i2c_device_id microread_i2c_id[] = {
313 { MICROREAD_I2C_DRIVER_NAME, 0},
314 { }
315};
316MODULE_DEVICE_TABLE(i2c, microread_i2c_id);
317
318static struct i2c_driver microread_i2c_driver = {
319 .driver = {
320 .name = MICROREAD_I2C_DRIVER_NAME,
321 },
322 .probe = microread_i2c_probe,
323 .remove = microread_i2c_remove,
324 .id_table = microread_i2c_id,
325};
326
327module_i2c_driver(microread_i2c_driver);
328
329MODULE_LICENSE("GPL");
330MODULE_DESCRIPTION(DRIVER_DESC);