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c656aa4c LP |
1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* | |
3 | * Driver for NXP PN532 NFC Chip - UART transport layer | |
4 | * | |
5 | * Copyright (C) 2018 Lemonage Software GmbH | |
6 | * Author: Lars Pöschel <poeschel@lemonage.de> | |
7 | * All rights reserved. | |
8 | */ | |
9 | ||
10 | #include <linux/device.h> | |
11 | #include <linux/kernel.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/nfc.h> | |
14 | #include <linux/netdevice.h> | |
15 | #include <linux/of.h> | |
16 | #include <linux/serdev.h> | |
17 | #include "pn533.h" | |
18 | ||
19 | #define PN532_UART_SKB_BUFF_LEN (PN533_CMD_DATAEXCH_DATA_MAXLEN * 2) | |
20 | ||
21 | enum send_wakeup { | |
22 | PN532_SEND_NO_WAKEUP = 0, | |
23 | PN532_SEND_WAKEUP, | |
24 | PN532_SEND_LAST_WAKEUP, | |
25 | }; | |
26 | ||
27 | ||
28 | struct pn532_uart_phy { | |
29 | struct serdev_device *serdev; | |
30 | struct sk_buff *recv_skb; | |
31 | struct pn533 *priv; | |
32 | /* | |
33 | * send_wakeup variable is used to control if we need to send a wakeup | |
34 | * request to the pn532 chip prior to our actual command. There is a | |
35 | * little propability of a race condition. We decided to not mutex the | |
36 | * variable as the worst that could happen is, that we send a wakeup | |
37 | * to the chip that is already awake. This does not hurt. It is a | |
38 | * no-op to the chip. | |
39 | */ | |
40 | enum send_wakeup send_wakeup; | |
41 | struct timer_list cmd_timeout; | |
42 | struct sk_buff *cur_out_buf; | |
43 | }; | |
44 | ||
45 | static int pn532_uart_send_frame(struct pn533 *dev, | |
46 | struct sk_buff *out) | |
47 | { | |
48 | /* wakeup sequence and dummy bytes for waiting time */ | |
49 | static const u8 wakeup[] = { | |
50 | 0x55, 0x55, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | |
51 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; | |
52 | struct pn532_uart_phy *pn532 = dev->phy; | |
53 | int err; | |
54 | ||
55 | print_hex_dump_debug("PN532_uart TX: ", DUMP_PREFIX_NONE, 16, 1, | |
56 | out->data, out->len, false); | |
57 | ||
58 | pn532->cur_out_buf = out; | |
59 | if (pn532->send_wakeup) { | |
60 | err = serdev_device_write(pn532->serdev, | |
61 | wakeup, sizeof(wakeup), | |
62 | MAX_SCHEDULE_TIMEOUT); | |
63 | if (err < 0) | |
64 | return err; | |
65 | } | |
66 | ||
67 | if (pn532->send_wakeup == PN532_SEND_LAST_WAKEUP) | |
68 | pn532->send_wakeup = PN532_SEND_NO_WAKEUP; | |
69 | ||
70 | err = serdev_device_write(pn532->serdev, out->data, out->len, | |
71 | MAX_SCHEDULE_TIMEOUT); | |
72 | if (err < 0) | |
73 | return err; | |
74 | ||
75 | mod_timer(&pn532->cmd_timeout, HZ / 40 + jiffies); | |
76 | return 0; | |
77 | } | |
78 | ||
79 | static int pn532_uart_send_ack(struct pn533 *dev, gfp_t flags) | |
80 | { | |
81 | /* spec 7.1.1.3: Preamble, SoPC (2), ACK Code (2), Postamble */ | |
82 | static const u8 ack[PN533_STD_FRAME_ACK_SIZE] = { | |
83 | 0x00, 0x00, 0xff, 0x00, 0xff, 0x00}; | |
84 | struct pn532_uart_phy *pn532 = dev->phy; | |
85 | int err; | |
86 | ||
87 | err = serdev_device_write(pn532->serdev, ack, sizeof(ack), | |
88 | MAX_SCHEDULE_TIMEOUT); | |
89 | if (err < 0) | |
90 | return err; | |
91 | ||
92 | return 0; | |
93 | } | |
94 | ||
95 | static void pn532_uart_abort_cmd(struct pn533 *dev, gfp_t flags) | |
96 | { | |
97 | /* An ack will cancel the last issued command */ | |
98 | pn532_uart_send_ack(dev, flags); | |
99 | /* schedule cmd_complete_work to finish current command execution */ | |
100 | pn533_recv_frame(dev, NULL, -ENOENT); | |
101 | } | |
102 | ||
1e37be7d | 103 | static int pn532_dev_up(struct pn533 *dev) |
c656aa4c LP |
104 | { |
105 | struct pn532_uart_phy *pn532 = dev->phy; | |
1e37be7d LP |
106 | int ret = 0; |
107 | ||
108 | ret = serdev_device_open(pn532->serdev); | |
109 | if (ret) | |
110 | return ret; | |
c656aa4c | 111 | |
c656aa4c | 112 | pn532->send_wakeup = PN532_SEND_LAST_WAKEUP; |
1e37be7d | 113 | return ret; |
c656aa4c LP |
114 | } |
115 | ||
1e37be7d | 116 | static int pn532_dev_down(struct pn533 *dev) |
c656aa4c LP |
117 | { |
118 | struct pn532_uart_phy *pn532 = dev->phy; | |
119 | ||
120 | serdev_device_close(pn532->serdev); | |
121 | pn532->send_wakeup = PN532_SEND_WAKEUP; | |
1e37be7d LP |
122 | |
123 | return 0; | |
c656aa4c LP |
124 | } |
125 | ||
126 | static struct pn533_phy_ops uart_phy_ops = { | |
127 | .send_frame = pn532_uart_send_frame, | |
128 | .send_ack = pn532_uart_send_ack, | |
129 | .abort_cmd = pn532_uart_abort_cmd, | |
130 | .dev_up = pn532_dev_up, | |
131 | .dev_down = pn532_dev_down, | |
132 | }; | |
133 | ||
134 | static void pn532_cmd_timeout(struct timer_list *t) | |
135 | { | |
136 | struct pn532_uart_phy *dev = from_timer(dev, t, cmd_timeout); | |
137 | ||
138 | pn532_uart_send_frame(dev->priv, dev->cur_out_buf); | |
139 | } | |
140 | ||
141 | /* | |
142 | * scans the buffer if it contains a pn532 frame. It is not checked if the | |
143 | * frame is really valid. This is later done with pn533_rx_frame_is_valid. | |
144 | * This is useful for malformed or errornous transmitted frames. Adjusts the | |
145 | * bufferposition where the frame starts, since pn533_recv_frame expects a | |
146 | * well formed frame. | |
147 | */ | |
148 | static int pn532_uart_rx_is_frame(struct sk_buff *skb) | |
149 | { | |
150 | struct pn533_std_frame *std; | |
151 | struct pn533_ext_frame *ext; | |
152 | u16 frame_len; | |
153 | int i; | |
154 | ||
155 | for (i = 0; i + PN533_STD_FRAME_ACK_SIZE <= skb->len; i++) { | |
156 | std = (struct pn533_std_frame *)&skb->data[i]; | |
157 | /* search start code */ | |
158 | if (std->start_frame != cpu_to_be16(PN533_STD_FRAME_SOF)) | |
159 | continue; | |
160 | ||
161 | /* frame type */ | |
162 | switch (std->datalen) { | |
163 | case PN533_FRAME_DATALEN_ACK: | |
164 | if (std->datalen_checksum == 0xff) { | |
165 | skb_pull(skb, i); | |
166 | return 1; | |
167 | } | |
168 | ||
169 | break; | |
170 | case PN533_FRAME_DATALEN_ERROR: | |
171 | if ((std->datalen_checksum == 0xff) && | |
172 | (skb->len >= | |
173 | PN533_STD_ERROR_FRAME_SIZE)) { | |
174 | skb_pull(skb, i); | |
175 | return 1; | |
176 | } | |
177 | ||
178 | break; | |
179 | case PN533_FRAME_DATALEN_EXTENDED: | |
180 | ext = (struct pn533_ext_frame *)&skb->data[i]; | |
181 | frame_len = be16_to_cpu(ext->datalen); | |
182 | if (skb->len >= frame_len + | |
183 | sizeof(struct pn533_ext_frame) + | |
184 | 2 /* CKS + Postamble */) { | |
185 | skb_pull(skb, i); | |
186 | return 1; | |
187 | } | |
188 | ||
189 | break; | |
190 | default: /* normal information frame */ | |
191 | frame_len = std->datalen; | |
192 | if (skb->len >= frame_len + | |
193 | sizeof(struct pn533_std_frame) + | |
194 | 2 /* CKS + Postamble */) { | |
195 | skb_pull(skb, i); | |
196 | return 1; | |
197 | } | |
198 | ||
199 | break; | |
200 | } | |
201 | } | |
202 | ||
203 | return 0; | |
204 | } | |
205 | ||
206 | static int pn532_receive_buf(struct serdev_device *serdev, | |
207 | const unsigned char *data, size_t count) | |
208 | { | |
209 | struct pn532_uart_phy *dev = serdev_device_get_drvdata(serdev); | |
210 | size_t i; | |
211 | ||
212 | del_timer(&dev->cmd_timeout); | |
213 | for (i = 0; i < count; i++) { | |
214 | skb_put_u8(dev->recv_skb, *data++); | |
215 | if (!pn532_uart_rx_is_frame(dev->recv_skb)) | |
216 | continue; | |
217 | ||
218 | pn533_recv_frame(dev->priv, dev->recv_skb, 0); | |
219 | dev->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, GFP_KERNEL); | |
220 | if (!dev->recv_skb) | |
221 | return 0; | |
222 | } | |
223 | ||
224 | return i; | |
225 | } | |
226 | ||
227 | static struct serdev_device_ops pn532_serdev_ops = { | |
228 | .receive_buf = pn532_receive_buf, | |
229 | .write_wakeup = serdev_device_write_wakeup, | |
230 | }; | |
231 | ||
232 | static const struct of_device_id pn532_uart_of_match[] = { | |
233 | { .compatible = "nxp,pn532", }, | |
234 | {}, | |
235 | }; | |
236 | MODULE_DEVICE_TABLE(of, pn532_uart_of_match); | |
237 | ||
238 | static int pn532_uart_probe(struct serdev_device *serdev) | |
239 | { | |
240 | struct pn532_uart_phy *pn532; | |
241 | struct pn533 *priv; | |
242 | int err; | |
243 | ||
244 | err = -ENOMEM; | |
245 | pn532 = kzalloc(sizeof(*pn532), GFP_KERNEL); | |
246 | if (!pn532) | |
247 | goto err_exit; | |
248 | ||
249 | pn532->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, GFP_KERNEL); | |
250 | if (!pn532->recv_skb) | |
251 | goto err_free; | |
252 | ||
253 | pn532->serdev = serdev; | |
254 | serdev_device_set_drvdata(serdev, pn532); | |
255 | serdev_device_set_client_ops(serdev, &pn532_serdev_ops); | |
256 | err = serdev_device_open(serdev); | |
257 | if (err) { | |
258 | dev_err(&serdev->dev, "Unable to open device\n"); | |
259 | goto err_skb; | |
260 | } | |
261 | ||
262 | err = serdev_device_set_baudrate(serdev, 115200); | |
263 | if (err != 115200) { | |
264 | err = -EINVAL; | |
265 | goto err_serdev; | |
266 | } | |
267 | ||
268 | serdev_device_set_flow_control(serdev, false); | |
269 | pn532->send_wakeup = PN532_SEND_WAKEUP; | |
270 | timer_setup(&pn532->cmd_timeout, pn532_cmd_timeout, 0); | |
e4a5dc18 | 271 | priv = pn53x_common_init(PN533_DEVICE_PN532_AUTOPOLL, |
c656aa4c LP |
272 | PN533_PROTO_REQ_ACK_RESP, |
273 | pn532, &uart_phy_ops, NULL, | |
274 | &pn532->serdev->dev); | |
275 | if (IS_ERR(priv)) { | |
276 | err = PTR_ERR(priv); | |
277 | goto err_serdev; | |
278 | } | |
279 | ||
280 | pn532->priv = priv; | |
281 | err = pn533_finalize_setup(pn532->priv); | |
282 | if (err) | |
283 | goto err_clean; | |
284 | ||
285 | serdev_device_close(serdev); | |
286 | err = pn53x_register_nfc(priv, PN533_NO_TYPE_B_PROTOCOLS, &serdev->dev); | |
287 | if (err) { | |
288 | pn53x_common_clean(pn532->priv); | |
289 | goto err_skb; | |
290 | } | |
291 | ||
292 | return err; | |
293 | ||
294 | err_clean: | |
295 | pn53x_common_clean(pn532->priv); | |
296 | err_serdev: | |
297 | serdev_device_close(serdev); | |
298 | err_skb: | |
299 | kfree_skb(pn532->recv_skb); | |
300 | err_free: | |
301 | kfree(pn532); | |
302 | err_exit: | |
303 | return err; | |
304 | } | |
305 | ||
306 | static void pn532_uart_remove(struct serdev_device *serdev) | |
307 | { | |
308 | struct pn532_uart_phy *pn532 = serdev_device_get_drvdata(serdev); | |
309 | ||
310 | pn53x_unregister_nfc(pn532->priv); | |
311 | serdev_device_close(serdev); | |
312 | pn53x_common_clean(pn532->priv); | |
313 | kfree_skb(pn532->recv_skb); | |
314 | kfree(pn532); | |
315 | } | |
316 | ||
317 | static struct serdev_device_driver pn532_uart_driver = { | |
318 | .probe = pn532_uart_probe, | |
319 | .remove = pn532_uart_remove, | |
320 | .driver = { | |
321 | .name = "pn532_uart", | |
a70bbbe3 | 322 | .of_match_table = pn532_uart_of_match, |
c656aa4c LP |
323 | }, |
324 | }; | |
325 | ||
326 | module_serdev_device_driver(pn532_uart_driver); | |
327 | ||
328 | MODULE_AUTHOR("Lars Pöschel <poeschel@lemonage.de>"); | |
329 | MODULE_DESCRIPTION("PN532 UART driver"); | |
330 | MODULE_LICENSE("GPL"); |