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