1 // SPDX-License-Identifier: GPL-2.0-only <<
2 /* 1 /*
3 * Copyright (C) 2013 Intel Corporation. All 2 * Copyright (C) 2013 Intel Corporation. All rights reserved.
>> 3 *
>> 4 * This program is free software; you can redistribute it and/or modify it
>> 5 * under the terms and conditions of the GNU General Public License,
>> 6 * version 2, as published by the Free Software Foundation.
>> 7 *
>> 8 * This program is distributed in the hope it will be useful, but WITHOUT
>> 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
>> 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
>> 11 * more details.
>> 12 *
>> 13 * You should have received a copy of the GNU General Public License along with
>> 14 * this program; if not, write to the Free Software Foundation, Inc.,
>> 15 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
>> 16 *
4 */ 17 */
5 18
6 #define pr_fmt(fmt) "nci_spi: %s: " fmt, __fun 19 #define pr_fmt(fmt) "nci_spi: %s: " fmt, __func__
7 20
8 #include <linux/module.h> 21 #include <linux/module.h>
9 22
10 #include <linux/export.h> 23 #include <linux/export.h>
11 #include <linux/spi/spi.h> 24 #include <linux/spi/spi.h>
12 #include <linux/crc-ccitt.h> 25 #include <linux/crc-ccitt.h>
13 #include <net/nfc/nci_core.h> 26 #include <net/nfc/nci_core.h>
14 27
15 #define NCI_SPI_ACK_SHIFT 6 28 #define NCI_SPI_ACK_SHIFT 6
16 #define NCI_SPI_MSB_PAYLOAD_MASK 0x3F 29 #define NCI_SPI_MSB_PAYLOAD_MASK 0x3F
17 30
18 #define NCI_SPI_SEND_TIMEOUT (NCI_CMD_TIMEO 31 #define NCI_SPI_SEND_TIMEOUT (NCI_CMD_TIMEOUT > NCI_DATA_TIMEOUT ? \
19 NCI_CM 32 NCI_CMD_TIMEOUT : NCI_DATA_TIMEOUT)
20 33
21 #define NCI_SPI_DIRECT_WRITE 0x01 34 #define NCI_SPI_DIRECT_WRITE 0x01
22 #define NCI_SPI_DIRECT_READ 0x02 35 #define NCI_SPI_DIRECT_READ 0x02
23 36
24 #define ACKNOWLEDGE_NONE 0 37 #define ACKNOWLEDGE_NONE 0
25 #define ACKNOWLEDGE_ACK 1 38 #define ACKNOWLEDGE_ACK 1
26 #define ACKNOWLEDGE_NACK 2 39 #define ACKNOWLEDGE_NACK 2
27 40
28 #define CRC_INIT 0xFFFF 41 #define CRC_INIT 0xFFFF
29 42
30 static int __nci_spi_send(struct nci_spi *nspi !! 43 static int __nci_spi_send(struct nci_spi *nspi, struct sk_buff *skb,
31 int cs_change) 44 int cs_change)
32 { 45 {
33 struct spi_message m; 46 struct spi_message m;
34 struct spi_transfer t; 47 struct spi_transfer t;
35 48
36 memset(&t, 0, sizeof(struct spi_transf 49 memset(&t, 0, sizeof(struct spi_transfer));
37 /* a NULL skb means we just want the S 50 /* a NULL skb means we just want the SPI chip select line to raise */
38 if (skb) { 51 if (skb) {
39 t.tx_buf = skb->data; 52 t.tx_buf = skb->data;
40 t.len = skb->len; 53 t.len = skb->len;
41 } else { 54 } else {
42 /* still set tx_buf non NULL t 55 /* still set tx_buf non NULL to make the driver happy */
43 t.tx_buf = &t; 56 t.tx_buf = &t;
44 t.len = 0; 57 t.len = 0;
45 } 58 }
46 t.cs_change = cs_change; 59 t.cs_change = cs_change;
47 t.delay.value = nspi->xfer_udelay; !! 60 t.delay_usecs = nspi->xfer_udelay;
48 t.delay.unit = SPI_DELAY_UNIT_USECS; <<
49 t.speed_hz = nspi->xfer_speed_hz; 61 t.speed_hz = nspi->xfer_speed_hz;
50 62
51 spi_message_init(&m); 63 spi_message_init(&m);
52 spi_message_add_tail(&t, &m); 64 spi_message_add_tail(&t, &m);
53 65
54 return spi_sync(nspi->spi, &m); 66 return spi_sync(nspi->spi, &m);
55 } 67 }
56 68
57 int nci_spi_send(struct nci_spi *nspi, 69 int nci_spi_send(struct nci_spi *nspi,
58 struct completion *write_hand 70 struct completion *write_handshake_completion,
59 struct sk_buff *skb) 71 struct sk_buff *skb)
60 { 72 {
61 unsigned int payload_len = skb->len; 73 unsigned int payload_len = skb->len;
62 unsigned char *hdr; 74 unsigned char *hdr;
63 int ret; 75 int ret;
64 long completion_rc; 76 long completion_rc;
65 77
66 /* add the NCI SPI header to the start 78 /* add the NCI SPI header to the start of the buffer */
67 hdr = skb_push(skb, NCI_SPI_HDR_LEN); 79 hdr = skb_push(skb, NCI_SPI_HDR_LEN);
68 hdr[0] = NCI_SPI_DIRECT_WRITE; 80 hdr[0] = NCI_SPI_DIRECT_WRITE;
69 hdr[1] = nspi->acknowledge_mode; 81 hdr[1] = nspi->acknowledge_mode;
70 hdr[2] = payload_len >> 8; 82 hdr[2] = payload_len >> 8;
71 hdr[3] = payload_len & 0xFF; 83 hdr[3] = payload_len & 0xFF;
72 84
73 if (nspi->acknowledge_mode == NCI_SPI_ 85 if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
74 u16 crc; 86 u16 crc;
75 87
76 crc = crc_ccitt(CRC_INIT, skb- 88 crc = crc_ccitt(CRC_INIT, skb->data, skb->len);
77 skb_put_u8(skb, crc >> 8); 89 skb_put_u8(skb, crc >> 8);
78 skb_put_u8(skb, crc & 0xFF); 90 skb_put_u8(skb, crc & 0xFF);
79 } 91 }
80 92
81 if (write_handshake_completion) { 93 if (write_handshake_completion) {
82 /* Trick SPI driver to raise c 94 /* Trick SPI driver to raise chip select */
83 ret = __nci_spi_send(nspi, NUL 95 ret = __nci_spi_send(nspi, NULL, 1);
84 if (ret) 96 if (ret)
85 goto done; 97 goto done;
86 98
87 /* wait for NFC chip hardware 99 /* wait for NFC chip hardware handshake to complete */
88 if (wait_for_completion_timeou 100 if (wait_for_completion_timeout(write_handshake_completion,
89 101 msecs_to_jiffies(1000)) == 0) {
90 ret = -ETIME; 102 ret = -ETIME;
91 goto done; 103 goto done;
92 } 104 }
93 } 105 }
94 106
95 ret = __nci_spi_send(nspi, skb, 0); 107 ret = __nci_spi_send(nspi, skb, 0);
96 if (ret != 0 || nspi->acknowledge_mode 108 if (ret != 0 || nspi->acknowledge_mode == NCI_SPI_CRC_DISABLED)
97 goto done; 109 goto done;
98 110
99 reinit_completion(&nspi->req_completio 111 reinit_completion(&nspi->req_completion);
100 completion_rc = wait_for_completion_in 112 completion_rc = wait_for_completion_interruptible_timeout(
101 113 &nspi->req_completion,
102 114 NCI_SPI_SEND_TIMEOUT);
103 115
104 if (completion_rc <= 0 || nspi->req_re 116 if (completion_rc <= 0 || nspi->req_result == ACKNOWLEDGE_NACK)
105 ret = -EIO; 117 ret = -EIO;
106 118
107 done: 119 done:
108 kfree_skb(skb); 120 kfree_skb(skb);
109 121
110 return ret; 122 return ret;
111 } 123 }
112 EXPORT_SYMBOL_GPL(nci_spi_send); 124 EXPORT_SYMBOL_GPL(nci_spi_send);
113 125
114 /* ---- Interface to NCI SPI drivers ---- */ 126 /* ---- Interface to NCI SPI drivers ---- */
115 127
116 /** 128 /**
117 * nci_spi_allocate_spi - allocate a new nci s 129 * nci_spi_allocate_spi - allocate a new nci spi
118 * 130 *
119 * @spi: SPI device 131 * @spi: SPI device
120 * @acknowledge_mode: Acknowledge mode used by 132 * @acknowledge_mode: Acknowledge mode used by the NFC device
121 * @delay: delay between transactions in us 133 * @delay: delay between transactions in us
122 * @ndev: nci dev to send incoming nci frames 134 * @ndev: nci dev to send incoming nci frames to
123 */ 135 */
124 struct nci_spi *nci_spi_allocate_spi(struct sp 136 struct nci_spi *nci_spi_allocate_spi(struct spi_device *spi,
125 u8 acknow 137 u8 acknowledge_mode, unsigned int delay,
126 struct nc 138 struct nci_dev *ndev)
127 { 139 {
128 struct nci_spi *nspi; 140 struct nci_spi *nspi;
129 141
130 nspi = devm_kzalloc(&spi->dev, sizeof( 142 nspi = devm_kzalloc(&spi->dev, sizeof(struct nci_spi), GFP_KERNEL);
131 if (!nspi) 143 if (!nspi)
132 return NULL; 144 return NULL;
133 145
134 nspi->acknowledge_mode = acknowledge_m 146 nspi->acknowledge_mode = acknowledge_mode;
135 nspi->xfer_udelay = delay; 147 nspi->xfer_udelay = delay;
136 /* Use controller max SPI speed by def 148 /* Use controller max SPI speed by default */
137 nspi->xfer_speed_hz = 0; 149 nspi->xfer_speed_hz = 0;
138 nspi->spi = spi; 150 nspi->spi = spi;
139 nspi->ndev = ndev; 151 nspi->ndev = ndev;
140 init_completion(&nspi->req_completion) 152 init_completion(&nspi->req_completion);
141 153
142 return nspi; 154 return nspi;
143 } 155 }
144 EXPORT_SYMBOL_GPL(nci_spi_allocate_spi); 156 EXPORT_SYMBOL_GPL(nci_spi_allocate_spi);
145 157
146 static int send_acknowledge(struct nci_spi *ns 158 static int send_acknowledge(struct nci_spi *nspi, u8 acknowledge)
147 { 159 {
148 struct sk_buff *skb; 160 struct sk_buff *skb;
149 unsigned char *hdr; 161 unsigned char *hdr;
150 u16 crc; 162 u16 crc;
151 int ret; 163 int ret;
152 164
153 skb = nci_skb_alloc(nspi->ndev, 0, GFP 165 skb = nci_skb_alloc(nspi->ndev, 0, GFP_KERNEL);
154 if (!skb) 166 if (!skb)
155 return -ENOMEM; 167 return -ENOMEM;
156 168
157 /* add the NCI SPI header to the start 169 /* add the NCI SPI header to the start of the buffer */
158 hdr = skb_push(skb, NCI_SPI_HDR_LEN); 170 hdr = skb_push(skb, NCI_SPI_HDR_LEN);
159 hdr[0] = NCI_SPI_DIRECT_WRITE; 171 hdr[0] = NCI_SPI_DIRECT_WRITE;
160 hdr[1] = NCI_SPI_CRC_ENABLED; 172 hdr[1] = NCI_SPI_CRC_ENABLED;
161 hdr[2] = acknowledge << NCI_SPI_ACK_SH 173 hdr[2] = acknowledge << NCI_SPI_ACK_SHIFT;
162 hdr[3] = 0; 174 hdr[3] = 0;
163 175
164 crc = crc_ccitt(CRC_INIT, skb->data, s 176 crc = crc_ccitt(CRC_INIT, skb->data, skb->len);
165 skb_put_u8(skb, crc >> 8); 177 skb_put_u8(skb, crc >> 8);
166 skb_put_u8(skb, crc & 0xFF); 178 skb_put_u8(skb, crc & 0xFF);
167 179
168 ret = __nci_spi_send(nspi, skb, 0); 180 ret = __nci_spi_send(nspi, skb, 0);
169 181
170 kfree_skb(skb); 182 kfree_skb(skb);
171 183
172 return ret; 184 return ret;
173 } 185 }
174 186
175 static struct sk_buff *__nci_spi_read(struct n 187 static struct sk_buff *__nci_spi_read(struct nci_spi *nspi)
176 { 188 {
177 struct sk_buff *skb; 189 struct sk_buff *skb;
178 struct spi_message m; 190 struct spi_message m;
179 unsigned char req[2], resp_hdr[2]; 191 unsigned char req[2], resp_hdr[2];
180 struct spi_transfer tx, rx; 192 struct spi_transfer tx, rx;
181 unsigned short rx_len = 0; 193 unsigned short rx_len = 0;
182 int ret; 194 int ret;
183 195
184 spi_message_init(&m); 196 spi_message_init(&m);
185 197
186 memset(&tx, 0, sizeof(struct spi_trans 198 memset(&tx, 0, sizeof(struct spi_transfer));
187 req[0] = NCI_SPI_DIRECT_READ; 199 req[0] = NCI_SPI_DIRECT_READ;
188 req[1] = nspi->acknowledge_mode; 200 req[1] = nspi->acknowledge_mode;
189 tx.tx_buf = req; 201 tx.tx_buf = req;
190 tx.len = 2; 202 tx.len = 2;
191 tx.cs_change = 0; 203 tx.cs_change = 0;
192 tx.speed_hz = nspi->xfer_speed_hz; 204 tx.speed_hz = nspi->xfer_speed_hz;
193 spi_message_add_tail(&tx, &m); 205 spi_message_add_tail(&tx, &m);
194 206
195 memset(&rx, 0, sizeof(struct spi_trans 207 memset(&rx, 0, sizeof(struct spi_transfer));
196 rx.rx_buf = resp_hdr; 208 rx.rx_buf = resp_hdr;
197 rx.len = 2; 209 rx.len = 2;
198 rx.cs_change = 1; 210 rx.cs_change = 1;
199 rx.speed_hz = nspi->xfer_speed_hz; 211 rx.speed_hz = nspi->xfer_speed_hz;
200 spi_message_add_tail(&rx, &m); 212 spi_message_add_tail(&rx, &m);
201 213
202 ret = spi_sync(nspi->spi, &m); 214 ret = spi_sync(nspi->spi, &m);
203 if (ret) 215 if (ret)
204 return NULL; 216 return NULL;
205 217
206 if (nspi->acknowledge_mode == NCI_SPI_ 218 if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED)
207 rx_len = ((resp_hdr[0] & NCI_S 219 rx_len = ((resp_hdr[0] & NCI_SPI_MSB_PAYLOAD_MASK) << 8) +
208 resp_hdr[1] + 220 resp_hdr[1] + NCI_SPI_CRC_LEN;
209 else 221 else
210 rx_len = (resp_hdr[0] << 8) | 222 rx_len = (resp_hdr[0] << 8) | resp_hdr[1];
211 223
212 skb = nci_skb_alloc(nspi->ndev, rx_len 224 skb = nci_skb_alloc(nspi->ndev, rx_len, GFP_KERNEL);
213 if (!skb) 225 if (!skb)
214 return NULL; 226 return NULL;
215 227
216 spi_message_init(&m); 228 spi_message_init(&m);
217 229
218 memset(&rx, 0, sizeof(struct spi_trans 230 memset(&rx, 0, sizeof(struct spi_transfer));
219 rx.rx_buf = skb_put(skb, rx_len); 231 rx.rx_buf = skb_put(skb, rx_len);
220 rx.len = rx_len; 232 rx.len = rx_len;
221 rx.cs_change = 0; 233 rx.cs_change = 0;
222 rx.delay.value = nspi->xfer_udelay; !! 234 rx.delay_usecs = nspi->xfer_udelay;
223 rx.delay.unit = SPI_DELAY_UNIT_USECS; <<
224 rx.speed_hz = nspi->xfer_speed_hz; 235 rx.speed_hz = nspi->xfer_speed_hz;
225 spi_message_add_tail(&rx, &m); 236 spi_message_add_tail(&rx, &m);
226 237
227 ret = spi_sync(nspi->spi, &m); 238 ret = spi_sync(nspi->spi, &m);
228 if (ret) 239 if (ret)
229 goto receive_error; 240 goto receive_error;
230 241
231 if (nspi->acknowledge_mode == NCI_SPI_ 242 if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
232 *(u8 *)skb_push(skb, 1) = resp 243 *(u8 *)skb_push(skb, 1) = resp_hdr[1];
233 *(u8 *)skb_push(skb, 1) = resp 244 *(u8 *)skb_push(skb, 1) = resp_hdr[0];
234 } 245 }
235 246
236 return skb; 247 return skb;
237 248
238 receive_error: 249 receive_error:
239 kfree_skb(skb); 250 kfree_skb(skb);
240 251
241 return NULL; 252 return NULL;
242 } 253 }
243 254
244 static int nci_spi_check_crc(struct sk_buff *s 255 static int nci_spi_check_crc(struct sk_buff *skb)
245 { 256 {
246 u16 crc_data = (skb->data[skb->len - 2 257 u16 crc_data = (skb->data[skb->len - 2] << 8) |
247 skb->data[skb->len - 1 258 skb->data[skb->len - 1];
248 int ret; 259 int ret;
249 260
250 ret = (crc_ccitt(CRC_INIT, skb->data, 261 ret = (crc_ccitt(CRC_INIT, skb->data, skb->len - NCI_SPI_CRC_LEN)
251 == crc_data); 262 == crc_data);
252 263
253 skb_trim(skb, skb->len - NCI_SPI_CRC_L 264 skb_trim(skb, skb->len - NCI_SPI_CRC_LEN);
254 265
255 return ret; 266 return ret;
256 } 267 }
257 268
258 static u8 nci_spi_get_ack(struct sk_buff *skb) 269 static u8 nci_spi_get_ack(struct sk_buff *skb)
259 { 270 {
260 u8 ret; 271 u8 ret;
261 272
262 ret = skb->data[0] >> NCI_SPI_ACK_SHIF 273 ret = skb->data[0] >> NCI_SPI_ACK_SHIFT;
263 274
264 /* Remove NFCC part of the header: ACK 275 /* Remove NFCC part of the header: ACK, NACK and MSB payload len */
265 skb_pull(skb, 2); 276 skb_pull(skb, 2);
266 277
267 return ret; 278 return ret;
268 } 279 }
269 280
270 /** 281 /**
271 * nci_spi_read - read frame from NCI SPI driv 282 * nci_spi_read - read frame from NCI SPI drivers
272 * 283 *
273 * @nspi: The nci spi 284 * @nspi: The nci spi
274 * Context: can sleep 285 * Context: can sleep
275 * 286 *
276 * This call may only be used from a context t 287 * This call may only be used from a context that may sleep. The sleep
277 * is non-interruptible, and has no timeout. 288 * is non-interruptible, and has no timeout.
278 * 289 *
279 * It returns an allocated skb containing the 290 * It returns an allocated skb containing the frame on success, or NULL.
280 */ 291 */
281 struct sk_buff *nci_spi_read(struct nci_spi *n 292 struct sk_buff *nci_spi_read(struct nci_spi *nspi)
282 { 293 {
283 struct sk_buff *skb; 294 struct sk_buff *skb;
284 295
285 /* Retrieve frame from SPI */ 296 /* Retrieve frame from SPI */
286 skb = __nci_spi_read(nspi); 297 skb = __nci_spi_read(nspi);
287 if (!skb) 298 if (!skb)
288 goto done; 299 goto done;
289 300
290 if (nspi->acknowledge_mode == NCI_SPI_ 301 if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
291 if (!nci_spi_check_crc(skb)) { 302 if (!nci_spi_check_crc(skb)) {
292 send_acknowledge(nspi, 303 send_acknowledge(nspi, ACKNOWLEDGE_NACK);
293 goto done; 304 goto done;
294 } 305 }
295 306
296 /* In case of acknowledged mod 307 /* In case of acknowledged mode: if ACK or NACK received,
297 * unblock completion of lates 308 * unblock completion of latest frame sent.
298 */ 309 */
299 nspi->req_result = nci_spi_get 310 nspi->req_result = nci_spi_get_ack(skb);
300 if (nspi->req_result) 311 if (nspi->req_result)
301 complete(&nspi->req_co 312 complete(&nspi->req_completion);
302 } 313 }
303 314
304 /* If there is no payload (ACK/NACK on 315 /* If there is no payload (ACK/NACK only frame),
305 * free the socket buffer 316 * free the socket buffer
306 */ 317 */
307 if (!skb->len) { 318 if (!skb->len) {
308 kfree_skb(skb); 319 kfree_skb(skb);
309 skb = NULL; 320 skb = NULL;
310 goto done; 321 goto done;
311 } 322 }
312 323
313 if (nspi->acknowledge_mode == NCI_SPI_ 324 if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED)
314 send_acknowledge(nspi, ACKNOWL 325 send_acknowledge(nspi, ACKNOWLEDGE_ACK);
315 326
316 done: 327 done:
317 328
318 return skb; 329 return skb;
319 } 330 }
320 EXPORT_SYMBOL_GPL(nci_spi_read); 331 EXPORT_SYMBOL_GPL(nci_spi_read);
321 332
322 MODULE_DESCRIPTION("NFC Controller Interface ( <<
323 MODULE_LICENSE("GPL"); 333 MODULE_LICENSE("GPL");
324 334
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