xref: /linux/drivers/net/ethernet/qualcomm/qca_spi.c (revision bfd5bb6f90af092aa345b15cd78143956a13c2a8)
1 /*
2  *   Copyright (c) 2011, 2012, Qualcomm Atheros Communications Inc.
3  *   Copyright (c) 2014, I2SE GmbH
4  *
5  *   Permission to use, copy, modify, and/or distribute this software
6  *   for any purpose with or without fee is hereby granted, provided
7  *   that the above copyright notice and this permission notice appear
8  *   in all copies.
9  *
10  *   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
11  *   WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
12  *   WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
13  *   THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
14  *   CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
15  *   LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
16  *   NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
17  *   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 /*   This module implements the Qualcomm Atheros SPI protocol for
21  *   kernel-based SPI device; it is essentially an Ethernet-to-SPI
22  *   serial converter;
23  */
24 
25 #include <linux/errno.h>
26 #include <linux/etherdevice.h>
27 #include <linux/if_arp.h>
28 #include <linux/if_ether.h>
29 #include <linux/init.h>
30 #include <linux/interrupt.h>
31 #include <linux/jiffies.h>
32 #include <linux/kernel.h>
33 #include <linux/kthread.h>
34 #include <linux/module.h>
35 #include <linux/moduleparam.h>
36 #include <linux/netdevice.h>
37 #include <linux/of.h>
38 #include <linux/of_device.h>
39 #include <linux/of_net.h>
40 #include <linux/sched.h>
41 #include <linux/skbuff.h>
42 #include <linux/spi/spi.h>
43 #include <linux/types.h>
44 
45 #include "qca_7k.h"
46 #include "qca_7k_common.h"
47 #include "qca_debug.h"
48 #include "qca_spi.h"
49 
50 #define MAX_DMA_BURST_LEN 5000
51 
52 /*   Modules parameters     */
53 #define QCASPI_CLK_SPEED_MIN 1000000
54 #define QCASPI_CLK_SPEED_MAX 16000000
55 #define QCASPI_CLK_SPEED     8000000
56 static int qcaspi_clkspeed;
57 module_param(qcaspi_clkspeed, int, 0);
58 MODULE_PARM_DESC(qcaspi_clkspeed, "SPI bus clock speed (Hz). Use 1000000-16000000.");
59 
60 #define QCASPI_BURST_LEN_MIN 1
61 #define QCASPI_BURST_LEN_MAX MAX_DMA_BURST_LEN
62 static int qcaspi_burst_len = MAX_DMA_BURST_LEN;
63 module_param(qcaspi_burst_len, int, 0);
64 MODULE_PARM_DESC(qcaspi_burst_len, "Number of data bytes per burst. Use 1-5000.");
65 
66 #define QCASPI_PLUGGABLE_MIN 0
67 #define QCASPI_PLUGGABLE_MAX 1
68 static int qcaspi_pluggable = QCASPI_PLUGGABLE_MIN;
69 module_param(qcaspi_pluggable, int, 0);
70 MODULE_PARM_DESC(qcaspi_pluggable, "Pluggable SPI connection (yes/no).");
71 
72 #define QCASPI_TX_TIMEOUT (1 * HZ)
73 #define QCASPI_QCA7K_REBOOT_TIME_MS 1000
74 
75 static void
76 start_spi_intr_handling(struct qcaspi *qca, u16 *intr_cause)
77 {
78 	*intr_cause = 0;
79 
80 	qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, 0);
81 	qcaspi_read_register(qca, SPI_REG_INTR_CAUSE, intr_cause);
82 	netdev_dbg(qca->net_dev, "interrupts: 0x%04x\n", *intr_cause);
83 }
84 
85 static void
86 end_spi_intr_handling(struct qcaspi *qca, u16 intr_cause)
87 {
88 	u16 intr_enable = (SPI_INT_CPU_ON |
89 			   SPI_INT_PKT_AVLBL |
90 			   SPI_INT_RDBUF_ERR |
91 			   SPI_INT_WRBUF_ERR);
92 
93 	qcaspi_write_register(qca, SPI_REG_INTR_CAUSE, intr_cause);
94 	qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, intr_enable);
95 	netdev_dbg(qca->net_dev, "acking int: 0x%04x\n", intr_cause);
96 }
97 
98 static u32
99 qcaspi_write_burst(struct qcaspi *qca, u8 *src, u32 len)
100 {
101 	__be16 cmd;
102 	struct spi_message *msg = &qca->spi_msg2;
103 	struct spi_transfer *transfer = &qca->spi_xfer2[0];
104 	int ret;
105 
106 	cmd = cpu_to_be16(QCA7K_SPI_WRITE | QCA7K_SPI_EXTERNAL);
107 	transfer->tx_buf = &cmd;
108 	transfer->rx_buf = NULL;
109 	transfer->len = QCASPI_CMD_LEN;
110 	transfer = &qca->spi_xfer2[1];
111 	transfer->tx_buf = src;
112 	transfer->rx_buf = NULL;
113 	transfer->len = len;
114 
115 	ret = spi_sync(qca->spi_dev, msg);
116 
117 	if (ret || (msg->actual_length != QCASPI_CMD_LEN + len)) {
118 		qcaspi_spi_error(qca);
119 		return 0;
120 	}
121 
122 	return len;
123 }
124 
125 static u32
126 qcaspi_write_legacy(struct qcaspi *qca, u8 *src, u32 len)
127 {
128 	struct spi_message *msg = &qca->spi_msg1;
129 	struct spi_transfer *transfer = &qca->spi_xfer1;
130 	int ret;
131 
132 	transfer->tx_buf = src;
133 	transfer->rx_buf = NULL;
134 	transfer->len = len;
135 
136 	ret = spi_sync(qca->spi_dev, msg);
137 
138 	if (ret || (msg->actual_length != len)) {
139 		qcaspi_spi_error(qca);
140 		return 0;
141 	}
142 
143 	return len;
144 }
145 
146 static u32
147 qcaspi_read_burst(struct qcaspi *qca, u8 *dst, u32 len)
148 {
149 	struct spi_message *msg = &qca->spi_msg2;
150 	__be16 cmd;
151 	struct spi_transfer *transfer = &qca->spi_xfer2[0];
152 	int ret;
153 
154 	cmd = cpu_to_be16(QCA7K_SPI_READ | QCA7K_SPI_EXTERNAL);
155 	transfer->tx_buf = &cmd;
156 	transfer->rx_buf = NULL;
157 	transfer->len = QCASPI_CMD_LEN;
158 	transfer = &qca->spi_xfer2[1];
159 	transfer->tx_buf = NULL;
160 	transfer->rx_buf = dst;
161 	transfer->len = len;
162 
163 	ret = spi_sync(qca->spi_dev, msg);
164 
165 	if (ret || (msg->actual_length != QCASPI_CMD_LEN + len)) {
166 		qcaspi_spi_error(qca);
167 		return 0;
168 	}
169 
170 	return len;
171 }
172 
173 static u32
174 qcaspi_read_legacy(struct qcaspi *qca, u8 *dst, u32 len)
175 {
176 	struct spi_message *msg = &qca->spi_msg1;
177 	struct spi_transfer *transfer = &qca->spi_xfer1;
178 	int ret;
179 
180 	transfer->tx_buf = NULL;
181 	transfer->rx_buf = dst;
182 	transfer->len = len;
183 
184 	ret = spi_sync(qca->spi_dev, msg);
185 
186 	if (ret || (msg->actual_length != len)) {
187 		qcaspi_spi_error(qca);
188 		return 0;
189 	}
190 
191 	return len;
192 }
193 
194 static int
195 qcaspi_tx_cmd(struct qcaspi *qca, u16 cmd)
196 {
197 	__be16 tx_data;
198 	struct spi_message *msg = &qca->spi_msg1;
199 	struct spi_transfer *transfer = &qca->spi_xfer1;
200 	int ret;
201 
202 	tx_data = cpu_to_be16(cmd);
203 	transfer->len = sizeof(tx_data);
204 	transfer->tx_buf = &tx_data;
205 	transfer->rx_buf = NULL;
206 
207 	ret = spi_sync(qca->spi_dev, msg);
208 
209 	if (!ret)
210 		ret = msg->status;
211 
212 	if (ret)
213 		qcaspi_spi_error(qca);
214 
215 	return ret;
216 }
217 
218 static int
219 qcaspi_tx_frame(struct qcaspi *qca, struct sk_buff *skb)
220 {
221 	u32 count;
222 	u32 written;
223 	u32 offset;
224 	u32 len;
225 
226 	len = skb->len;
227 
228 	qcaspi_write_register(qca, SPI_REG_BFR_SIZE, len);
229 	if (qca->legacy_mode)
230 		qcaspi_tx_cmd(qca, QCA7K_SPI_WRITE | QCA7K_SPI_EXTERNAL);
231 
232 	offset = 0;
233 	while (len) {
234 		count = len;
235 		if (count > qca->burst_len)
236 			count = qca->burst_len;
237 
238 		if (qca->legacy_mode) {
239 			written = qcaspi_write_legacy(qca,
240 						      skb->data + offset,
241 						      count);
242 		} else {
243 			written = qcaspi_write_burst(qca,
244 						     skb->data + offset,
245 						     count);
246 		}
247 
248 		if (written != count)
249 			return -1;
250 
251 		offset += count;
252 		len -= count;
253 	}
254 
255 	return 0;
256 }
257 
258 static int
259 qcaspi_transmit(struct qcaspi *qca)
260 {
261 	struct net_device_stats *n_stats = &qca->net_dev->stats;
262 	u16 available = 0;
263 	u32 pkt_len;
264 	u16 new_head;
265 	u16 packets = 0;
266 
267 	if (qca->txr.skb[qca->txr.head] == NULL)
268 		return 0;
269 
270 	qcaspi_read_register(qca, SPI_REG_WRBUF_SPC_AVA, &available);
271 
272 	while (qca->txr.skb[qca->txr.head]) {
273 		pkt_len = qca->txr.skb[qca->txr.head]->len + QCASPI_HW_PKT_LEN;
274 
275 		if (available < pkt_len) {
276 			if (packets == 0)
277 				qca->stats.write_buf_miss++;
278 			break;
279 		}
280 
281 		if (qcaspi_tx_frame(qca, qca->txr.skb[qca->txr.head]) == -1) {
282 			qca->stats.write_err++;
283 			return -1;
284 		}
285 
286 		packets++;
287 		n_stats->tx_packets++;
288 		n_stats->tx_bytes += qca->txr.skb[qca->txr.head]->len;
289 		available -= pkt_len;
290 
291 		/* remove the skb from the queue */
292 		/* XXX After inconsistent lock states netif_tx_lock()
293 		 * has been replaced by netif_tx_lock_bh() and so on.
294 		 */
295 		netif_tx_lock_bh(qca->net_dev);
296 		dev_kfree_skb(qca->txr.skb[qca->txr.head]);
297 		qca->txr.skb[qca->txr.head] = NULL;
298 		qca->txr.size -= pkt_len;
299 		new_head = qca->txr.head + 1;
300 		if (new_head >= qca->txr.count)
301 			new_head = 0;
302 		qca->txr.head = new_head;
303 		if (netif_queue_stopped(qca->net_dev))
304 			netif_wake_queue(qca->net_dev);
305 		netif_tx_unlock_bh(qca->net_dev);
306 	}
307 
308 	return 0;
309 }
310 
311 static int
312 qcaspi_receive(struct qcaspi *qca)
313 {
314 	struct net_device *net_dev = qca->net_dev;
315 	struct net_device_stats *n_stats = &net_dev->stats;
316 	u16 available = 0;
317 	u32 bytes_read;
318 	u8 *cp;
319 
320 	/* Allocate rx SKB if we don't have one available. */
321 	if (!qca->rx_skb) {
322 		qca->rx_skb = netdev_alloc_skb_ip_align(net_dev,
323 							net_dev->mtu +
324 							VLAN_ETH_HLEN);
325 		if (!qca->rx_skb) {
326 			netdev_dbg(net_dev, "out of RX resources\n");
327 			qca->stats.out_of_mem++;
328 			return -1;
329 		}
330 	}
331 
332 	/* Read the packet size. */
333 	qcaspi_read_register(qca, SPI_REG_RDBUF_BYTE_AVA, &available);
334 	netdev_dbg(net_dev, "qcaspi_receive: SPI_REG_RDBUF_BYTE_AVA: Value: %08x\n",
335 		   available);
336 
337 	if (available == 0) {
338 		netdev_dbg(net_dev, "qcaspi_receive called without any data being available!\n");
339 		return -1;
340 	}
341 
342 	qcaspi_write_register(qca, SPI_REG_BFR_SIZE, available);
343 
344 	if (qca->legacy_mode)
345 		qcaspi_tx_cmd(qca, QCA7K_SPI_READ | QCA7K_SPI_EXTERNAL);
346 
347 	while (available) {
348 		u32 count = available;
349 
350 		if (count > qca->burst_len)
351 			count = qca->burst_len;
352 
353 		if (qca->legacy_mode) {
354 			bytes_read = qcaspi_read_legacy(qca, qca->rx_buffer,
355 							count);
356 		} else {
357 			bytes_read = qcaspi_read_burst(qca, qca->rx_buffer,
358 						       count);
359 		}
360 
361 		netdev_dbg(net_dev, "available: %d, byte read: %d\n",
362 			   available, bytes_read);
363 
364 		if (bytes_read) {
365 			available -= bytes_read;
366 		} else {
367 			qca->stats.read_err++;
368 			return -1;
369 		}
370 
371 		cp = qca->rx_buffer;
372 
373 		while ((bytes_read--) && (qca->rx_skb)) {
374 			s32 retcode;
375 
376 			retcode = qcafrm_fsm_decode(&qca->frm_handle,
377 						    qca->rx_skb->data,
378 						    skb_tailroom(qca->rx_skb),
379 						    *cp);
380 			cp++;
381 			switch (retcode) {
382 			case QCAFRM_GATHER:
383 			case QCAFRM_NOHEAD:
384 				break;
385 			case QCAFRM_NOTAIL:
386 				netdev_dbg(net_dev, "no RX tail\n");
387 				n_stats->rx_errors++;
388 				n_stats->rx_dropped++;
389 				break;
390 			case QCAFRM_INVLEN:
391 				netdev_dbg(net_dev, "invalid RX length\n");
392 				n_stats->rx_errors++;
393 				n_stats->rx_dropped++;
394 				break;
395 			default:
396 				qca->rx_skb->dev = qca->net_dev;
397 				n_stats->rx_packets++;
398 				n_stats->rx_bytes += retcode;
399 				skb_put(qca->rx_skb, retcode);
400 				qca->rx_skb->protocol = eth_type_trans(
401 					qca->rx_skb, qca->rx_skb->dev);
402 				qca->rx_skb->ip_summed = CHECKSUM_UNNECESSARY;
403 				netif_rx_ni(qca->rx_skb);
404 				qca->rx_skb = netdev_alloc_skb_ip_align(net_dev,
405 					net_dev->mtu + VLAN_ETH_HLEN);
406 				if (!qca->rx_skb) {
407 					netdev_dbg(net_dev, "out of RX resources\n");
408 					n_stats->rx_errors++;
409 					qca->stats.out_of_mem++;
410 					break;
411 				}
412 			}
413 		}
414 	}
415 
416 	return 0;
417 }
418 
419 /*   Check that tx ring stores only so much bytes
420  *   that fit into the internal QCA buffer.
421  */
422 
423 static int
424 qcaspi_tx_ring_has_space(struct tx_ring *txr)
425 {
426 	if (txr->skb[txr->tail])
427 		return 0;
428 
429 	return (txr->size + QCAFRM_MAX_LEN < QCASPI_HW_BUF_LEN) ? 1 : 0;
430 }
431 
432 /*   Flush the tx ring. This function is only safe to
433  *   call from the qcaspi_spi_thread.
434  */
435 
436 static void
437 qcaspi_flush_tx_ring(struct qcaspi *qca)
438 {
439 	int i;
440 
441 	/* XXX After inconsistent lock states netif_tx_lock()
442 	 * has been replaced by netif_tx_lock_bh() and so on.
443 	 */
444 	netif_tx_lock_bh(qca->net_dev);
445 	for (i = 0; i < TX_RING_MAX_LEN; i++) {
446 		if (qca->txr.skb[i]) {
447 			dev_kfree_skb(qca->txr.skb[i]);
448 			qca->txr.skb[i] = NULL;
449 			qca->net_dev->stats.tx_dropped++;
450 		}
451 	}
452 	qca->txr.tail = 0;
453 	qca->txr.head = 0;
454 	qca->txr.size = 0;
455 	netif_tx_unlock_bh(qca->net_dev);
456 }
457 
458 static void
459 qcaspi_qca7k_sync(struct qcaspi *qca, int event)
460 {
461 	u16 signature = 0;
462 	u16 spi_config;
463 	u16 wrbuf_space = 0;
464 	static u16 reset_count;
465 
466 	if (event == QCASPI_EVENT_CPUON) {
467 		/* Read signature twice, if not valid
468 		 * go back to unknown state.
469 		 */
470 		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
471 		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
472 		if (signature != QCASPI_GOOD_SIGNATURE) {
473 			qca->sync = QCASPI_SYNC_UNKNOWN;
474 			netdev_dbg(qca->net_dev, "sync: got CPU on, but signature was invalid, restart\n");
475 		} else {
476 			/* ensure that the WRBUF is empty */
477 			qcaspi_read_register(qca, SPI_REG_WRBUF_SPC_AVA,
478 					     &wrbuf_space);
479 			if (wrbuf_space != QCASPI_HW_BUF_LEN) {
480 				netdev_dbg(qca->net_dev, "sync: got CPU on, but wrbuf not empty. reset!\n");
481 				qca->sync = QCASPI_SYNC_UNKNOWN;
482 			} else {
483 				netdev_dbg(qca->net_dev, "sync: got CPU on, now in sync\n");
484 				qca->sync = QCASPI_SYNC_READY;
485 				return;
486 			}
487 		}
488 	}
489 
490 	switch (qca->sync) {
491 	case QCASPI_SYNC_READY:
492 		/* Read signature, if not valid go to unknown state. */
493 		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
494 		if (signature != QCASPI_GOOD_SIGNATURE) {
495 			qca->sync = QCASPI_SYNC_UNKNOWN;
496 			netdev_dbg(qca->net_dev, "sync: bad signature, restart\n");
497 			/* don't reset right away */
498 			return;
499 		}
500 		break;
501 	case QCASPI_SYNC_UNKNOWN:
502 		/* Read signature, if not valid stay in unknown state */
503 		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
504 		if (signature != QCASPI_GOOD_SIGNATURE) {
505 			netdev_dbg(qca->net_dev, "sync: could not read signature to reset device, retry.\n");
506 			return;
507 		}
508 
509 		/* TODO: use GPIO to reset QCA7000 in legacy mode*/
510 		netdev_dbg(qca->net_dev, "sync: resetting device.\n");
511 		qcaspi_read_register(qca, SPI_REG_SPI_CONFIG, &spi_config);
512 		spi_config |= QCASPI_SLAVE_RESET_BIT;
513 		qcaspi_write_register(qca, SPI_REG_SPI_CONFIG, spi_config);
514 
515 		qca->sync = QCASPI_SYNC_RESET;
516 		qca->stats.trig_reset++;
517 		reset_count = 0;
518 		break;
519 	case QCASPI_SYNC_RESET:
520 		reset_count++;
521 		netdev_dbg(qca->net_dev, "sync: waiting for CPU on, count %u.\n",
522 			   reset_count);
523 		if (reset_count >= QCASPI_RESET_TIMEOUT) {
524 			/* reset did not seem to take place, try again */
525 			qca->sync = QCASPI_SYNC_UNKNOWN;
526 			qca->stats.reset_timeout++;
527 			netdev_dbg(qca->net_dev, "sync: reset timeout, restarting process.\n");
528 		}
529 		break;
530 	}
531 }
532 
533 static int
534 qcaspi_spi_thread(void *data)
535 {
536 	struct qcaspi *qca = data;
537 	u16 intr_cause = 0;
538 
539 	netdev_info(qca->net_dev, "SPI thread created\n");
540 	while (!kthread_should_stop()) {
541 		set_current_state(TASK_INTERRUPTIBLE);
542 		if ((qca->intr_req == qca->intr_svc) &&
543 		    (qca->txr.skb[qca->txr.head] == NULL) &&
544 		    (qca->sync == QCASPI_SYNC_READY))
545 			schedule();
546 
547 		set_current_state(TASK_RUNNING);
548 
549 		netdev_dbg(qca->net_dev, "have work to do. int: %d, tx_skb: %p\n",
550 			   qca->intr_req - qca->intr_svc,
551 			   qca->txr.skb[qca->txr.head]);
552 
553 		qcaspi_qca7k_sync(qca, QCASPI_EVENT_UPDATE);
554 
555 		if (qca->sync != QCASPI_SYNC_READY) {
556 			netdev_dbg(qca->net_dev, "sync: not ready %u, turn off carrier and flush\n",
557 				   (unsigned int)qca->sync);
558 			netif_stop_queue(qca->net_dev);
559 			netif_carrier_off(qca->net_dev);
560 			qcaspi_flush_tx_ring(qca);
561 			msleep(QCASPI_QCA7K_REBOOT_TIME_MS);
562 		}
563 
564 		if (qca->intr_svc != qca->intr_req) {
565 			qca->intr_svc = qca->intr_req;
566 			start_spi_intr_handling(qca, &intr_cause);
567 
568 			if (intr_cause & SPI_INT_CPU_ON) {
569 				qcaspi_qca7k_sync(qca, QCASPI_EVENT_CPUON);
570 
571 				/* not synced. */
572 				if (qca->sync != QCASPI_SYNC_READY)
573 					continue;
574 
575 				qca->stats.device_reset++;
576 				netif_wake_queue(qca->net_dev);
577 				netif_carrier_on(qca->net_dev);
578 			}
579 
580 			if (intr_cause & SPI_INT_RDBUF_ERR) {
581 				/* restart sync */
582 				netdev_dbg(qca->net_dev, "===> rdbuf error!\n");
583 				qca->stats.read_buf_err++;
584 				qca->sync = QCASPI_SYNC_UNKNOWN;
585 				continue;
586 			}
587 
588 			if (intr_cause & SPI_INT_WRBUF_ERR) {
589 				/* restart sync */
590 				netdev_dbg(qca->net_dev, "===> wrbuf error!\n");
591 				qca->stats.write_buf_err++;
592 				qca->sync = QCASPI_SYNC_UNKNOWN;
593 				continue;
594 			}
595 
596 			/* can only handle other interrupts
597 			 * if sync has occurred
598 			 */
599 			if (qca->sync == QCASPI_SYNC_READY) {
600 				if (intr_cause & SPI_INT_PKT_AVLBL)
601 					qcaspi_receive(qca);
602 			}
603 
604 			end_spi_intr_handling(qca, intr_cause);
605 		}
606 
607 		if (qca->sync == QCASPI_SYNC_READY)
608 			qcaspi_transmit(qca);
609 	}
610 	set_current_state(TASK_RUNNING);
611 	netdev_info(qca->net_dev, "SPI thread exit\n");
612 
613 	return 0;
614 }
615 
616 static irqreturn_t
617 qcaspi_intr_handler(int irq, void *data)
618 {
619 	struct qcaspi *qca = data;
620 
621 	qca->intr_req++;
622 	if (qca->spi_thread &&
623 	    qca->spi_thread->state != TASK_RUNNING)
624 		wake_up_process(qca->spi_thread);
625 
626 	return IRQ_HANDLED;
627 }
628 
629 static int
630 qcaspi_netdev_open(struct net_device *dev)
631 {
632 	struct qcaspi *qca = netdev_priv(dev);
633 	int ret = 0;
634 
635 	if (!qca)
636 		return -EINVAL;
637 
638 	qca->intr_req = 1;
639 	qca->intr_svc = 0;
640 	qca->sync = QCASPI_SYNC_UNKNOWN;
641 	qcafrm_fsm_init_spi(&qca->frm_handle);
642 
643 	qca->spi_thread = kthread_run((void *)qcaspi_spi_thread,
644 				      qca, "%s", dev->name);
645 
646 	if (IS_ERR(qca->spi_thread)) {
647 		netdev_err(dev, "%s: unable to start kernel thread.\n",
648 			   QCASPI_DRV_NAME);
649 		return PTR_ERR(qca->spi_thread);
650 	}
651 
652 	ret = request_irq(qca->spi_dev->irq, qcaspi_intr_handler, 0,
653 			  dev->name, qca);
654 	if (ret) {
655 		netdev_err(dev, "%s: unable to get IRQ %d (irqval=%d).\n",
656 			   QCASPI_DRV_NAME, qca->spi_dev->irq, ret);
657 		kthread_stop(qca->spi_thread);
658 		return ret;
659 	}
660 
661 	/* SPI thread takes care of TX queue */
662 
663 	return 0;
664 }
665 
666 static int
667 qcaspi_netdev_close(struct net_device *dev)
668 {
669 	struct qcaspi *qca = netdev_priv(dev);
670 
671 	netif_stop_queue(dev);
672 
673 	qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, 0);
674 	free_irq(qca->spi_dev->irq, qca);
675 
676 	kthread_stop(qca->spi_thread);
677 	qca->spi_thread = NULL;
678 	qcaspi_flush_tx_ring(qca);
679 
680 	return 0;
681 }
682 
683 static netdev_tx_t
684 qcaspi_netdev_xmit(struct sk_buff *skb, struct net_device *dev)
685 {
686 	u32 frame_len;
687 	u8 *ptmp;
688 	struct qcaspi *qca = netdev_priv(dev);
689 	u16 new_tail;
690 	struct sk_buff *tskb;
691 	u8 pad_len = 0;
692 
693 	if (skb->len < QCAFRM_MIN_LEN)
694 		pad_len = QCAFRM_MIN_LEN - skb->len;
695 
696 	if (qca->txr.skb[qca->txr.tail]) {
697 		netdev_warn(qca->net_dev, "queue was unexpectedly full!\n");
698 		netif_stop_queue(qca->net_dev);
699 		qca->stats.ring_full++;
700 		return NETDEV_TX_BUSY;
701 	}
702 
703 	if ((skb_headroom(skb) < QCAFRM_HEADER_LEN) ||
704 	    (skb_tailroom(skb) < QCAFRM_FOOTER_LEN + pad_len)) {
705 		tskb = skb_copy_expand(skb, QCAFRM_HEADER_LEN,
706 				       QCAFRM_FOOTER_LEN + pad_len, GFP_ATOMIC);
707 		if (!tskb) {
708 			qca->stats.out_of_mem++;
709 			return NETDEV_TX_BUSY;
710 		}
711 		dev_kfree_skb(skb);
712 		skb = tskb;
713 	}
714 
715 	frame_len = skb->len + pad_len;
716 
717 	ptmp = skb_push(skb, QCAFRM_HEADER_LEN);
718 	qcafrm_create_header(ptmp, frame_len);
719 
720 	if (pad_len) {
721 		ptmp = skb_put_zero(skb, pad_len);
722 	}
723 
724 	ptmp = skb_put(skb, QCAFRM_FOOTER_LEN);
725 	qcafrm_create_footer(ptmp);
726 
727 	netdev_dbg(qca->net_dev, "Tx-ing packet: Size: 0x%08x\n",
728 		   skb->len);
729 
730 	qca->txr.size += skb->len + QCASPI_HW_PKT_LEN;
731 
732 	new_tail = qca->txr.tail + 1;
733 	if (new_tail >= qca->txr.count)
734 		new_tail = 0;
735 
736 	qca->txr.skb[qca->txr.tail] = skb;
737 	qca->txr.tail = new_tail;
738 
739 	if (!qcaspi_tx_ring_has_space(&qca->txr)) {
740 		netif_stop_queue(qca->net_dev);
741 		qca->stats.ring_full++;
742 	}
743 
744 	netif_trans_update(dev);
745 
746 	if (qca->spi_thread &&
747 	    qca->spi_thread->state != TASK_RUNNING)
748 		wake_up_process(qca->spi_thread);
749 
750 	return NETDEV_TX_OK;
751 }
752 
753 static void
754 qcaspi_netdev_tx_timeout(struct net_device *dev)
755 {
756 	struct qcaspi *qca = netdev_priv(dev);
757 
758 	netdev_info(qca->net_dev, "Transmit timeout at %ld, latency %ld\n",
759 		    jiffies, jiffies - dev_trans_start(dev));
760 	qca->net_dev->stats.tx_errors++;
761 	/* Trigger tx queue flush and QCA7000 reset */
762 	qca->sync = QCASPI_SYNC_UNKNOWN;
763 
764 	if (qca->spi_thread)
765 		wake_up_process(qca->spi_thread);
766 }
767 
768 static int
769 qcaspi_netdev_init(struct net_device *dev)
770 {
771 	struct qcaspi *qca = netdev_priv(dev);
772 
773 	dev->mtu = QCAFRM_MAX_MTU;
774 	dev->type = ARPHRD_ETHER;
775 	qca->clkspeed = qcaspi_clkspeed;
776 	qca->burst_len = qcaspi_burst_len;
777 	qca->spi_thread = NULL;
778 	qca->buffer_size = (dev->mtu + VLAN_ETH_HLEN + QCAFRM_HEADER_LEN +
779 		QCAFRM_FOOTER_LEN + 4) * 4;
780 
781 	memset(&qca->stats, 0, sizeof(struct qcaspi_stats));
782 
783 	qca->rx_buffer = kmalloc(qca->buffer_size, GFP_KERNEL);
784 	if (!qca->rx_buffer)
785 		return -ENOBUFS;
786 
787 	qca->rx_skb = netdev_alloc_skb_ip_align(dev, qca->net_dev->mtu +
788 						VLAN_ETH_HLEN);
789 	if (!qca->rx_skb) {
790 		kfree(qca->rx_buffer);
791 		netdev_info(qca->net_dev, "Failed to allocate RX sk_buff.\n");
792 		return -ENOBUFS;
793 	}
794 
795 	return 0;
796 }
797 
798 static void
799 qcaspi_netdev_uninit(struct net_device *dev)
800 {
801 	struct qcaspi *qca = netdev_priv(dev);
802 
803 	kfree(qca->rx_buffer);
804 	qca->buffer_size = 0;
805 	if (qca->rx_skb)
806 		dev_kfree_skb(qca->rx_skb);
807 }
808 
809 static const struct net_device_ops qcaspi_netdev_ops = {
810 	.ndo_init = qcaspi_netdev_init,
811 	.ndo_uninit = qcaspi_netdev_uninit,
812 	.ndo_open = qcaspi_netdev_open,
813 	.ndo_stop = qcaspi_netdev_close,
814 	.ndo_start_xmit = qcaspi_netdev_xmit,
815 	.ndo_set_mac_address = eth_mac_addr,
816 	.ndo_tx_timeout = qcaspi_netdev_tx_timeout,
817 	.ndo_validate_addr = eth_validate_addr,
818 };
819 
820 static void
821 qcaspi_netdev_setup(struct net_device *dev)
822 {
823 	struct qcaspi *qca = NULL;
824 
825 	dev->netdev_ops = &qcaspi_netdev_ops;
826 	qcaspi_set_ethtool_ops(dev);
827 	dev->watchdog_timeo = QCASPI_TX_TIMEOUT;
828 	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
829 	dev->tx_queue_len = 100;
830 
831 	/* MTU range: 46 - 1500 */
832 	dev->min_mtu = QCAFRM_MIN_MTU;
833 	dev->max_mtu = QCAFRM_MAX_MTU;
834 
835 	qca = netdev_priv(dev);
836 	memset(qca, 0, sizeof(struct qcaspi));
837 
838 	memset(&qca->spi_xfer1, 0, sizeof(struct spi_transfer));
839 	memset(&qca->spi_xfer2, 0, sizeof(struct spi_transfer) * 2);
840 
841 	spi_message_init(&qca->spi_msg1);
842 	spi_message_add_tail(&qca->spi_xfer1, &qca->spi_msg1);
843 
844 	spi_message_init(&qca->spi_msg2);
845 	spi_message_add_tail(&qca->spi_xfer2[0], &qca->spi_msg2);
846 	spi_message_add_tail(&qca->spi_xfer2[1], &qca->spi_msg2);
847 
848 	memset(&qca->txr, 0, sizeof(qca->txr));
849 	qca->txr.count = TX_RING_MAX_LEN;
850 }
851 
852 static const struct of_device_id qca_spi_of_match[] = {
853 	{ .compatible = "qca,qca7000" },
854 	{ /* sentinel */ }
855 };
856 MODULE_DEVICE_TABLE(of, qca_spi_of_match);
857 
858 static int
859 qca_spi_probe(struct spi_device *spi)
860 {
861 	struct qcaspi *qca = NULL;
862 	struct net_device *qcaspi_devs = NULL;
863 	u8 legacy_mode = 0;
864 	u16 signature;
865 	const char *mac;
866 
867 	if (!spi->dev.of_node) {
868 		dev_err(&spi->dev, "Missing device tree\n");
869 		return -EINVAL;
870 	}
871 
872 	legacy_mode = of_property_read_bool(spi->dev.of_node,
873 					    "qca,legacy-mode");
874 
875 	if (qcaspi_clkspeed == 0) {
876 		if (spi->max_speed_hz)
877 			qcaspi_clkspeed = spi->max_speed_hz;
878 		else
879 			qcaspi_clkspeed = QCASPI_CLK_SPEED;
880 	}
881 
882 	if ((qcaspi_clkspeed < QCASPI_CLK_SPEED_MIN) ||
883 	    (qcaspi_clkspeed > QCASPI_CLK_SPEED_MAX)) {
884 		dev_err(&spi->dev, "Invalid clkspeed: %d\n",
885 			qcaspi_clkspeed);
886 		return -EINVAL;
887 	}
888 
889 	if ((qcaspi_burst_len < QCASPI_BURST_LEN_MIN) ||
890 	    (qcaspi_burst_len > QCASPI_BURST_LEN_MAX)) {
891 		dev_err(&spi->dev, "Invalid burst len: %d\n",
892 			qcaspi_burst_len);
893 		return -EINVAL;
894 	}
895 
896 	if ((qcaspi_pluggable < QCASPI_PLUGGABLE_MIN) ||
897 	    (qcaspi_pluggable > QCASPI_PLUGGABLE_MAX)) {
898 		dev_err(&spi->dev, "Invalid pluggable: %d\n",
899 			qcaspi_pluggable);
900 		return -EINVAL;
901 	}
902 
903 	dev_info(&spi->dev, "ver=%s, clkspeed=%d, burst_len=%d, pluggable=%d\n",
904 		 QCASPI_DRV_VERSION,
905 		 qcaspi_clkspeed,
906 		 qcaspi_burst_len,
907 		 qcaspi_pluggable);
908 
909 	spi->mode = SPI_MODE_3;
910 	spi->max_speed_hz = qcaspi_clkspeed;
911 	if (spi_setup(spi) < 0) {
912 		dev_err(&spi->dev, "Unable to setup SPI device\n");
913 		return -EFAULT;
914 	}
915 
916 	qcaspi_devs = alloc_etherdev(sizeof(struct qcaspi));
917 	if (!qcaspi_devs)
918 		return -ENOMEM;
919 
920 	qcaspi_netdev_setup(qcaspi_devs);
921 	SET_NETDEV_DEV(qcaspi_devs, &spi->dev);
922 
923 	qca = netdev_priv(qcaspi_devs);
924 	if (!qca) {
925 		free_netdev(qcaspi_devs);
926 		dev_err(&spi->dev, "Fail to retrieve private structure\n");
927 		return -ENOMEM;
928 	}
929 	qca->net_dev = qcaspi_devs;
930 	qca->spi_dev = spi;
931 	qca->legacy_mode = legacy_mode;
932 
933 	spi_set_drvdata(spi, qcaspi_devs);
934 
935 	mac = of_get_mac_address(spi->dev.of_node);
936 
937 	if (mac)
938 		ether_addr_copy(qca->net_dev->dev_addr, mac);
939 
940 	if (!is_valid_ether_addr(qca->net_dev->dev_addr)) {
941 		eth_hw_addr_random(qca->net_dev);
942 		dev_info(&spi->dev, "Using random MAC address: %pM\n",
943 			 qca->net_dev->dev_addr);
944 	}
945 
946 	netif_carrier_off(qca->net_dev);
947 
948 	if (!qcaspi_pluggable) {
949 		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
950 		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
951 
952 		if (signature != QCASPI_GOOD_SIGNATURE) {
953 			dev_err(&spi->dev, "Invalid signature (0x%04X)\n",
954 				signature);
955 			free_netdev(qcaspi_devs);
956 			return -EFAULT;
957 		}
958 	}
959 
960 	if (register_netdev(qcaspi_devs)) {
961 		dev_err(&spi->dev, "Unable to register net device %s\n",
962 			qcaspi_devs->name);
963 		free_netdev(qcaspi_devs);
964 		return -EFAULT;
965 	}
966 
967 	qcaspi_init_device_debugfs(qca);
968 
969 	return 0;
970 }
971 
972 static int
973 qca_spi_remove(struct spi_device *spi)
974 {
975 	struct net_device *qcaspi_devs = spi_get_drvdata(spi);
976 	struct qcaspi *qca = netdev_priv(qcaspi_devs);
977 
978 	qcaspi_remove_device_debugfs(qca);
979 
980 	unregister_netdev(qcaspi_devs);
981 	free_netdev(qcaspi_devs);
982 
983 	return 0;
984 }
985 
986 static const struct spi_device_id qca_spi_id[] = {
987 	{ "qca7000", 0 },
988 	{ /* sentinel */ }
989 };
990 MODULE_DEVICE_TABLE(spi, qca_spi_id);
991 
992 static struct spi_driver qca_spi_driver = {
993 	.driver	= {
994 		.name	= QCASPI_DRV_NAME,
995 		.of_match_table = qca_spi_of_match,
996 	},
997 	.id_table = qca_spi_id,
998 	.probe    = qca_spi_probe,
999 	.remove   = qca_spi_remove,
1000 };
1001 module_spi_driver(qca_spi_driver);
1002 
1003 MODULE_DESCRIPTION("Qualcomm Atheros QCA7000 SPI Driver");
1004 MODULE_AUTHOR("Qualcomm Atheros Communications");
1005 MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
1006 MODULE_LICENSE("Dual BSD/GPL");
1007 MODULE_VERSION(QCASPI_DRV_VERSION);
1008