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_WRITE_VERIFY_MIN 0
73 #define QCASPI_WRITE_VERIFY_MAX 3
74 static int wr_verify = QCASPI_WRITE_VERIFY_MIN;
75 module_param(wr_verify, int, 0);
76 MODULE_PARM_DESC(wr_verify, "SPI register write verify trails. Use 0-3.");
77 
78 #define QCASPI_TX_TIMEOUT (1 * HZ)
79 #define QCASPI_QCA7K_REBOOT_TIME_MS 1000
80 
81 static void
82 start_spi_intr_handling(struct qcaspi *qca, u16 *intr_cause)
83 {
84 	*intr_cause = 0;
85 
86 	qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, 0, wr_verify);
87 	qcaspi_read_register(qca, SPI_REG_INTR_CAUSE, intr_cause);
88 	netdev_dbg(qca->net_dev, "interrupts: 0x%04x\n", *intr_cause);
89 }
90 
91 static void
92 end_spi_intr_handling(struct qcaspi *qca, u16 intr_cause)
93 {
94 	u16 intr_enable = (SPI_INT_CPU_ON |
95 			   SPI_INT_PKT_AVLBL |
96 			   SPI_INT_RDBUF_ERR |
97 			   SPI_INT_WRBUF_ERR);
98 
99 	qcaspi_write_register(qca, SPI_REG_INTR_CAUSE, intr_cause, 0);
100 	qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, intr_enable, wr_verify);
101 	netdev_dbg(qca->net_dev, "acking int: 0x%04x\n", intr_cause);
102 }
103 
104 static u32
105 qcaspi_write_burst(struct qcaspi *qca, u8 *src, u32 len)
106 {
107 	__be16 cmd;
108 	struct spi_message msg;
109 	struct spi_transfer transfer[2];
110 	int ret;
111 
112 	memset(&transfer, 0, sizeof(transfer));
113 	spi_message_init(&msg);
114 
115 	cmd = cpu_to_be16(QCA7K_SPI_WRITE | QCA7K_SPI_EXTERNAL);
116 	transfer[0].tx_buf = &cmd;
117 	transfer[0].len = QCASPI_CMD_LEN;
118 	transfer[1].tx_buf = src;
119 	transfer[1].len = len;
120 
121 	spi_message_add_tail(&transfer[0], &msg);
122 	spi_message_add_tail(&transfer[1], &msg);
123 	ret = spi_sync(qca->spi_dev, &msg);
124 
125 	if (ret || (msg.actual_length != QCASPI_CMD_LEN + len)) {
126 		qcaspi_spi_error(qca);
127 		return 0;
128 	}
129 
130 	return len;
131 }
132 
133 static u32
134 qcaspi_write_legacy(struct qcaspi *qca, u8 *src, u32 len)
135 {
136 	struct spi_message msg;
137 	struct spi_transfer transfer;
138 	int ret;
139 
140 	memset(&transfer, 0, sizeof(transfer));
141 	spi_message_init(&msg);
142 
143 	transfer.tx_buf = src;
144 	transfer.len = len;
145 
146 	spi_message_add_tail(&transfer, &msg);
147 	ret = spi_sync(qca->spi_dev, &msg);
148 
149 	if (ret || (msg.actual_length != len)) {
150 		qcaspi_spi_error(qca);
151 		return 0;
152 	}
153 
154 	return len;
155 }
156 
157 static u32
158 qcaspi_read_burst(struct qcaspi *qca, u8 *dst, u32 len)
159 {
160 	struct spi_message msg;
161 	__be16 cmd;
162 	struct spi_transfer transfer[2];
163 	int ret;
164 
165 	memset(&transfer, 0, sizeof(transfer));
166 	spi_message_init(&msg);
167 
168 	cmd = cpu_to_be16(QCA7K_SPI_READ | QCA7K_SPI_EXTERNAL);
169 	transfer[0].tx_buf = &cmd;
170 	transfer[0].len = QCASPI_CMD_LEN;
171 	transfer[1].rx_buf = dst;
172 	transfer[1].len = len;
173 
174 	spi_message_add_tail(&transfer[0], &msg);
175 	spi_message_add_tail(&transfer[1], &msg);
176 	ret = spi_sync(qca->spi_dev, &msg);
177 
178 	if (ret || (msg.actual_length != QCASPI_CMD_LEN + len)) {
179 		qcaspi_spi_error(qca);
180 		return 0;
181 	}
182 
183 	return len;
184 }
185 
186 static u32
187 qcaspi_read_legacy(struct qcaspi *qca, u8 *dst, u32 len)
188 {
189 	struct spi_message msg;
190 	struct spi_transfer transfer;
191 	int ret;
192 
193 	memset(&transfer, 0, sizeof(transfer));
194 	spi_message_init(&msg);
195 
196 	transfer.rx_buf = dst;
197 	transfer.len = len;
198 
199 	spi_message_add_tail(&transfer, &msg);
200 	ret = spi_sync(qca->spi_dev, &msg);
201 
202 	if (ret || (msg.actual_length != len)) {
203 		qcaspi_spi_error(qca);
204 		return 0;
205 	}
206 
207 	return len;
208 }
209 
210 static int
211 qcaspi_tx_cmd(struct qcaspi *qca, u16 cmd)
212 {
213 	__be16 tx_data;
214 	struct spi_message msg;
215 	struct spi_transfer transfer;
216 	int ret;
217 
218 	memset(&transfer, 0, sizeof(transfer));
219 
220 	spi_message_init(&msg);
221 
222 	tx_data = cpu_to_be16(cmd);
223 	transfer.len = sizeof(cmd);
224 	transfer.tx_buf = &tx_data;
225 	spi_message_add_tail(&transfer, &msg);
226 
227 	ret = spi_sync(qca->spi_dev, &msg);
228 
229 	if (!ret)
230 		ret = msg.status;
231 
232 	if (ret)
233 		qcaspi_spi_error(qca);
234 
235 	return ret;
236 }
237 
238 static int
239 qcaspi_tx_frame(struct qcaspi *qca, struct sk_buff *skb)
240 {
241 	u32 count;
242 	u32 written;
243 	u32 offset;
244 	u32 len;
245 
246 	len = skb->len;
247 
248 	qcaspi_write_register(qca, SPI_REG_BFR_SIZE, len, wr_verify);
249 	if (qca->legacy_mode)
250 		qcaspi_tx_cmd(qca, QCA7K_SPI_WRITE | QCA7K_SPI_EXTERNAL);
251 
252 	offset = 0;
253 	while (len) {
254 		count = len;
255 		if (count > qca->burst_len)
256 			count = qca->burst_len;
257 
258 		if (qca->legacy_mode) {
259 			written = qcaspi_write_legacy(qca,
260 						      skb->data + offset,
261 						      count);
262 		} else {
263 			written = qcaspi_write_burst(qca,
264 						     skb->data + offset,
265 						     count);
266 		}
267 
268 		if (written != count)
269 			return -1;
270 
271 		offset += count;
272 		len -= count;
273 	}
274 
275 	return 0;
276 }
277 
278 static int
279 qcaspi_transmit(struct qcaspi *qca)
280 {
281 	struct net_device_stats *n_stats = &qca->net_dev->stats;
282 	u16 available = 0;
283 	u32 pkt_len;
284 	u16 new_head;
285 	u16 packets = 0;
286 
287 	if (qca->txr.skb[qca->txr.head] == NULL)
288 		return 0;
289 
290 	qcaspi_read_register(qca, SPI_REG_WRBUF_SPC_AVA, &available);
291 
292 	while (qca->txr.skb[qca->txr.head]) {
293 		pkt_len = qca->txr.skb[qca->txr.head]->len + QCASPI_HW_PKT_LEN;
294 
295 		if (available < pkt_len) {
296 			if (packets == 0)
297 				qca->stats.write_buf_miss++;
298 			break;
299 		}
300 
301 		if (qcaspi_tx_frame(qca, qca->txr.skb[qca->txr.head]) == -1) {
302 			qca->stats.write_err++;
303 			return -1;
304 		}
305 
306 		packets++;
307 		n_stats->tx_packets++;
308 		n_stats->tx_bytes += qca->txr.skb[qca->txr.head]->len;
309 		available -= pkt_len;
310 
311 		/* remove the skb from the queue */
312 		/* XXX After inconsistent lock states netif_tx_lock()
313 		 * has been replaced by netif_tx_lock_bh() and so on.
314 		 */
315 		netif_tx_lock_bh(qca->net_dev);
316 		dev_kfree_skb(qca->txr.skb[qca->txr.head]);
317 		qca->txr.skb[qca->txr.head] = NULL;
318 		qca->txr.size -= pkt_len;
319 		new_head = qca->txr.head + 1;
320 		if (new_head >= qca->txr.count)
321 			new_head = 0;
322 		qca->txr.head = new_head;
323 		if (netif_queue_stopped(qca->net_dev))
324 			netif_wake_queue(qca->net_dev);
325 		netif_tx_unlock_bh(qca->net_dev);
326 	}
327 
328 	return 0;
329 }
330 
331 static int
332 qcaspi_receive(struct qcaspi *qca)
333 {
334 	struct net_device *net_dev = qca->net_dev;
335 	struct net_device_stats *n_stats = &net_dev->stats;
336 	u16 available = 0;
337 	u32 bytes_read;
338 	u8 *cp;
339 
340 	/* Allocate rx SKB if we don't have one available. */
341 	if (!qca->rx_skb) {
342 		qca->rx_skb = netdev_alloc_skb_ip_align(net_dev,
343 							net_dev->mtu +
344 							VLAN_ETH_HLEN);
345 		if (!qca->rx_skb) {
346 			netdev_dbg(net_dev, "out of RX resources\n");
347 			qca->stats.out_of_mem++;
348 			return -1;
349 		}
350 	}
351 
352 	/* Read the packet size. */
353 	qcaspi_read_register(qca, SPI_REG_RDBUF_BYTE_AVA, &available);
354 
355 	netdev_dbg(net_dev, "qcaspi_receive: SPI_REG_RDBUF_BYTE_AVA: Value: %08x\n",
356 		   available);
357 
358 	if (available == 0) {
359 		netdev_dbg(net_dev, "qcaspi_receive called without any data being available!\n");
360 		return -1;
361 	}
362 
363 	qcaspi_write_register(qca, SPI_REG_BFR_SIZE, available, wr_verify);
364 
365 	if (qca->legacy_mode)
366 		qcaspi_tx_cmd(qca, QCA7K_SPI_READ | QCA7K_SPI_EXTERNAL);
367 
368 	while (available) {
369 		u32 count = available;
370 
371 		if (count > qca->burst_len)
372 			count = qca->burst_len;
373 
374 		if (qca->legacy_mode) {
375 			bytes_read = qcaspi_read_legacy(qca, qca->rx_buffer,
376 							count);
377 		} else {
378 			bytes_read = qcaspi_read_burst(qca, qca->rx_buffer,
379 						       count);
380 		}
381 
382 		netdev_dbg(net_dev, "available: %d, byte read: %d\n",
383 			   available, bytes_read);
384 
385 		if (bytes_read) {
386 			available -= bytes_read;
387 		} else {
388 			qca->stats.read_err++;
389 			return -1;
390 		}
391 
392 		cp = qca->rx_buffer;
393 
394 		while ((bytes_read--) && (qca->rx_skb)) {
395 			s32 retcode;
396 
397 			retcode = qcafrm_fsm_decode(&qca->frm_handle,
398 						    qca->rx_skb->data,
399 						    skb_tailroom(qca->rx_skb),
400 						    *cp);
401 			cp++;
402 			switch (retcode) {
403 			case QCAFRM_GATHER:
404 			case QCAFRM_NOHEAD:
405 				break;
406 			case QCAFRM_NOTAIL:
407 				netdev_dbg(net_dev, "no RX tail\n");
408 				n_stats->rx_errors++;
409 				n_stats->rx_dropped++;
410 				break;
411 			case QCAFRM_INVLEN:
412 				netdev_dbg(net_dev, "invalid RX length\n");
413 				n_stats->rx_errors++;
414 				n_stats->rx_dropped++;
415 				break;
416 			default:
417 				qca->rx_skb->dev = qca->net_dev;
418 				n_stats->rx_packets++;
419 				n_stats->rx_bytes += retcode;
420 				skb_put(qca->rx_skb, retcode);
421 				qca->rx_skb->protocol = eth_type_trans(
422 					qca->rx_skb, qca->rx_skb->dev);
423 				qca->rx_skb->ip_summed = CHECKSUM_UNNECESSARY;
424 				netif_rx_ni(qca->rx_skb);
425 				qca->rx_skb = netdev_alloc_skb_ip_align(net_dev,
426 					net_dev->mtu + VLAN_ETH_HLEN);
427 				if (!qca->rx_skb) {
428 					netdev_dbg(net_dev, "out of RX resources\n");
429 					n_stats->rx_errors++;
430 					qca->stats.out_of_mem++;
431 					break;
432 				}
433 			}
434 		}
435 	}
436 
437 	return 0;
438 }
439 
440 /*   Check that tx ring stores only so much bytes
441  *   that fit into the internal QCA buffer.
442  */
443 
444 static int
445 qcaspi_tx_ring_has_space(struct tx_ring *txr)
446 {
447 	if (txr->skb[txr->tail])
448 		return 0;
449 
450 	return (txr->size + QCAFRM_MAX_LEN < QCASPI_HW_BUF_LEN) ? 1 : 0;
451 }
452 
453 /*   Flush the tx ring. This function is only safe to
454  *   call from the qcaspi_spi_thread.
455  */
456 
457 static void
458 qcaspi_flush_tx_ring(struct qcaspi *qca)
459 {
460 	int i;
461 
462 	/* XXX After inconsistent lock states netif_tx_lock()
463 	 * has been replaced by netif_tx_lock_bh() and so on.
464 	 */
465 	netif_tx_lock_bh(qca->net_dev);
466 	for (i = 0; i < TX_RING_MAX_LEN; i++) {
467 		if (qca->txr.skb[i]) {
468 			dev_kfree_skb(qca->txr.skb[i]);
469 			qca->txr.skb[i] = NULL;
470 			qca->net_dev->stats.tx_dropped++;
471 		}
472 	}
473 	qca->txr.tail = 0;
474 	qca->txr.head = 0;
475 	qca->txr.size = 0;
476 	netif_tx_unlock_bh(qca->net_dev);
477 }
478 
479 static void
480 qcaspi_qca7k_sync(struct qcaspi *qca, int event)
481 {
482 	u16 signature = 0;
483 	u16 spi_config;
484 	u16 wrbuf_space = 0;
485 	static u16 reset_count;
486 
487 	if (event == QCASPI_EVENT_CPUON) {
488 		/* Read signature twice, if not valid
489 		 * go back to unknown state.
490 		 */
491 		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
492 		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
493 		if (signature != QCASPI_GOOD_SIGNATURE) {
494 			qca->sync = QCASPI_SYNC_UNKNOWN;
495 			netdev_dbg(qca->net_dev, "sync: got CPU on, but signature was invalid, restart\n");
496 		} else {
497 			/* ensure that the WRBUF is empty */
498 			qcaspi_read_register(qca, SPI_REG_WRBUF_SPC_AVA,
499 					     &wrbuf_space);
500 			if (wrbuf_space != QCASPI_HW_BUF_LEN) {
501 				netdev_dbg(qca->net_dev, "sync: got CPU on, but wrbuf not empty. reset!\n");
502 				qca->sync = QCASPI_SYNC_UNKNOWN;
503 			} else {
504 				netdev_dbg(qca->net_dev, "sync: got CPU on, now in sync\n");
505 				qca->sync = QCASPI_SYNC_READY;
506 				return;
507 			}
508 		}
509 	}
510 
511 	switch (qca->sync) {
512 	case QCASPI_SYNC_READY:
513 		/* Read signature, if not valid go to unknown state. */
514 		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
515 		if (signature != QCASPI_GOOD_SIGNATURE) {
516 			qca->sync = QCASPI_SYNC_UNKNOWN;
517 			netdev_dbg(qca->net_dev, "sync: bad signature, restart\n");
518 			/* don't reset right away */
519 			return;
520 		}
521 		break;
522 	case QCASPI_SYNC_UNKNOWN:
523 		/* Read signature, if not valid stay in unknown state */
524 		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
525 		if (signature != QCASPI_GOOD_SIGNATURE) {
526 			netdev_dbg(qca->net_dev, "sync: could not read signature to reset device, retry.\n");
527 			return;
528 		}
529 
530 		/* TODO: use GPIO to reset QCA7000 in legacy mode*/
531 		netdev_dbg(qca->net_dev, "sync: resetting device.\n");
532 		qcaspi_read_register(qca, SPI_REG_SPI_CONFIG, &spi_config);
533 		spi_config |= QCASPI_SLAVE_RESET_BIT;
534 		qcaspi_write_register(qca, SPI_REG_SPI_CONFIG, spi_config, 0);
535 
536 		qca->sync = QCASPI_SYNC_RESET;
537 		qca->stats.trig_reset++;
538 		reset_count = 0;
539 		break;
540 	case QCASPI_SYNC_RESET:
541 		reset_count++;
542 		netdev_dbg(qca->net_dev, "sync: waiting for CPU on, count %u.\n",
543 			   reset_count);
544 		if (reset_count >= QCASPI_RESET_TIMEOUT) {
545 			/* reset did not seem to take place, try again */
546 			qca->sync = QCASPI_SYNC_UNKNOWN;
547 			qca->stats.reset_timeout++;
548 			netdev_dbg(qca->net_dev, "sync: reset timeout, restarting process.\n");
549 		}
550 		break;
551 	}
552 }
553 
554 static int
555 qcaspi_spi_thread(void *data)
556 {
557 	struct qcaspi *qca = data;
558 	u16 intr_cause = 0;
559 
560 	netdev_info(qca->net_dev, "SPI thread created\n");
561 	while (!kthread_should_stop()) {
562 		set_current_state(TASK_INTERRUPTIBLE);
563 		if ((qca->intr_req == qca->intr_svc) &&
564 		    (qca->txr.skb[qca->txr.head] == NULL) &&
565 		    (qca->sync == QCASPI_SYNC_READY))
566 			schedule();
567 
568 		set_current_state(TASK_RUNNING);
569 
570 		netdev_dbg(qca->net_dev, "have work to do. int: %d, tx_skb: %p\n",
571 			   qca->intr_req - qca->intr_svc,
572 			   qca->txr.skb[qca->txr.head]);
573 
574 		qcaspi_qca7k_sync(qca, QCASPI_EVENT_UPDATE);
575 
576 		if (qca->sync != QCASPI_SYNC_READY) {
577 			netdev_dbg(qca->net_dev, "sync: not ready %u, turn off carrier and flush\n",
578 				   (unsigned int)qca->sync);
579 			netif_stop_queue(qca->net_dev);
580 			netif_carrier_off(qca->net_dev);
581 			qcaspi_flush_tx_ring(qca);
582 			msleep(QCASPI_QCA7K_REBOOT_TIME_MS);
583 		}
584 
585 		if (qca->intr_svc != qca->intr_req) {
586 			qca->intr_svc = qca->intr_req;
587 			start_spi_intr_handling(qca, &intr_cause);
588 
589 			if (intr_cause & SPI_INT_CPU_ON) {
590 				qcaspi_qca7k_sync(qca, QCASPI_EVENT_CPUON);
591 
592 				/* not synced. */
593 				if (qca->sync != QCASPI_SYNC_READY)
594 					continue;
595 
596 				qca->stats.device_reset++;
597 				netif_wake_queue(qca->net_dev);
598 				netif_carrier_on(qca->net_dev);
599 			}
600 
601 			if (intr_cause & SPI_INT_RDBUF_ERR) {
602 				/* restart sync */
603 				netdev_dbg(qca->net_dev, "===> rdbuf error!\n");
604 				qca->stats.read_buf_err++;
605 				qca->sync = QCASPI_SYNC_UNKNOWN;
606 				continue;
607 			}
608 
609 			if (intr_cause & SPI_INT_WRBUF_ERR) {
610 				/* restart sync */
611 				netdev_dbg(qca->net_dev, "===> wrbuf error!\n");
612 				qca->stats.write_buf_err++;
613 				qca->sync = QCASPI_SYNC_UNKNOWN;
614 				continue;
615 			}
616 
617 			/* can only handle other interrupts
618 			 * if sync has occurred
619 			 */
620 			if (qca->sync == QCASPI_SYNC_READY) {
621 				if (intr_cause & SPI_INT_PKT_AVLBL)
622 					qcaspi_receive(qca);
623 			}
624 
625 			end_spi_intr_handling(qca, intr_cause);
626 		}
627 
628 		if (qca->sync == QCASPI_SYNC_READY)
629 			qcaspi_transmit(qca);
630 	}
631 	set_current_state(TASK_RUNNING);
632 	netdev_info(qca->net_dev, "SPI thread exit\n");
633 
634 	return 0;
635 }
636 
637 static irqreturn_t
638 qcaspi_intr_handler(int irq, void *data)
639 {
640 	struct qcaspi *qca = data;
641 
642 	qca->intr_req++;
643 	if (qca->spi_thread &&
644 	    qca->spi_thread->state != TASK_RUNNING)
645 		wake_up_process(qca->spi_thread);
646 
647 	return IRQ_HANDLED;
648 }
649 
650 static int
651 qcaspi_netdev_open(struct net_device *dev)
652 {
653 	struct qcaspi *qca = netdev_priv(dev);
654 	int ret = 0;
655 
656 	if (!qca)
657 		return -EINVAL;
658 
659 	qca->intr_req = 1;
660 	qca->intr_svc = 0;
661 	qca->sync = QCASPI_SYNC_UNKNOWN;
662 	qcafrm_fsm_init_spi(&qca->frm_handle);
663 
664 	qca->spi_thread = kthread_run((void *)qcaspi_spi_thread,
665 				      qca, "%s", dev->name);
666 
667 	if (IS_ERR(qca->spi_thread)) {
668 		netdev_err(dev, "%s: unable to start kernel thread.\n",
669 			   QCASPI_DRV_NAME);
670 		return PTR_ERR(qca->spi_thread);
671 	}
672 
673 	ret = request_irq(qca->spi_dev->irq, qcaspi_intr_handler, 0,
674 			  dev->name, qca);
675 	if (ret) {
676 		netdev_err(dev, "%s: unable to get IRQ %d (irqval=%d).\n",
677 			   QCASPI_DRV_NAME, qca->spi_dev->irq, ret);
678 		kthread_stop(qca->spi_thread);
679 		return ret;
680 	}
681 
682 	/* SPI thread takes care of TX queue */
683 
684 	return 0;
685 }
686 
687 static int
688 qcaspi_netdev_close(struct net_device *dev)
689 {
690 	struct qcaspi *qca = netdev_priv(dev);
691 
692 	netif_stop_queue(dev);
693 
694 	qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, 0, wr_verify);
695 	free_irq(qca->spi_dev->irq, qca);
696 
697 	kthread_stop(qca->spi_thread);
698 	qca->spi_thread = NULL;
699 	qcaspi_flush_tx_ring(qca);
700 
701 	return 0;
702 }
703 
704 static netdev_tx_t
705 qcaspi_netdev_xmit(struct sk_buff *skb, struct net_device *dev)
706 {
707 	u32 frame_len;
708 	u8 *ptmp;
709 	struct qcaspi *qca = netdev_priv(dev);
710 	u16 new_tail;
711 	struct sk_buff *tskb;
712 	u8 pad_len = 0;
713 
714 	if (skb->len < QCAFRM_MIN_LEN)
715 		pad_len = QCAFRM_MIN_LEN - skb->len;
716 
717 	if (qca->txr.skb[qca->txr.tail]) {
718 		netdev_warn(qca->net_dev, "queue was unexpectedly full!\n");
719 		netif_stop_queue(qca->net_dev);
720 		qca->stats.ring_full++;
721 		return NETDEV_TX_BUSY;
722 	}
723 
724 	if ((skb_headroom(skb) < QCAFRM_HEADER_LEN) ||
725 	    (skb_tailroom(skb) < QCAFRM_FOOTER_LEN + pad_len)) {
726 		tskb = skb_copy_expand(skb, QCAFRM_HEADER_LEN,
727 				       QCAFRM_FOOTER_LEN + pad_len, GFP_ATOMIC);
728 		if (!tskb) {
729 			qca->stats.out_of_mem++;
730 			return NETDEV_TX_BUSY;
731 		}
732 		dev_kfree_skb(skb);
733 		skb = tskb;
734 	}
735 
736 	frame_len = skb->len + pad_len;
737 
738 	ptmp = skb_push(skb, QCAFRM_HEADER_LEN);
739 	qcafrm_create_header(ptmp, frame_len);
740 
741 	if (pad_len) {
742 		ptmp = skb_put_zero(skb, pad_len);
743 	}
744 
745 	ptmp = skb_put(skb, QCAFRM_FOOTER_LEN);
746 	qcafrm_create_footer(ptmp);
747 
748 	netdev_dbg(qca->net_dev, "Tx-ing packet: Size: 0x%08x\n",
749 		   skb->len);
750 
751 	qca->txr.size += skb->len + QCASPI_HW_PKT_LEN;
752 
753 	new_tail = qca->txr.tail + 1;
754 	if (new_tail >= qca->txr.count)
755 		new_tail = 0;
756 
757 	qca->txr.skb[qca->txr.tail] = skb;
758 	qca->txr.tail = new_tail;
759 
760 	if (!qcaspi_tx_ring_has_space(&qca->txr)) {
761 		netif_stop_queue(qca->net_dev);
762 		qca->stats.ring_full++;
763 	}
764 
765 	netif_trans_update(dev);
766 
767 	if (qca->spi_thread &&
768 	    qca->spi_thread->state != TASK_RUNNING)
769 		wake_up_process(qca->spi_thread);
770 
771 	return NETDEV_TX_OK;
772 }
773 
774 static void
775 qcaspi_netdev_tx_timeout(struct net_device *dev)
776 {
777 	struct qcaspi *qca = netdev_priv(dev);
778 
779 	netdev_info(qca->net_dev, "Transmit timeout at %ld, latency %ld\n",
780 		    jiffies, jiffies - dev_trans_start(dev));
781 	qca->net_dev->stats.tx_errors++;
782 	/* Trigger tx queue flush and QCA7000 reset */
783 	qca->sync = QCASPI_SYNC_UNKNOWN;
784 
785 	if (qca->spi_thread)
786 		wake_up_process(qca->spi_thread);
787 }
788 
789 static int
790 qcaspi_netdev_init(struct net_device *dev)
791 {
792 	struct qcaspi *qca = netdev_priv(dev);
793 
794 	dev->mtu = QCAFRM_MAX_MTU;
795 	dev->type = ARPHRD_ETHER;
796 	qca->clkspeed = qcaspi_clkspeed;
797 	qca->burst_len = qcaspi_burst_len;
798 	qca->spi_thread = NULL;
799 	qca->buffer_size = (dev->mtu + VLAN_ETH_HLEN + QCAFRM_HEADER_LEN +
800 		QCAFRM_FOOTER_LEN + 4) * 4;
801 
802 	memset(&qca->stats, 0, sizeof(struct qcaspi_stats));
803 
804 	qca->rx_buffer = kmalloc(qca->buffer_size, GFP_KERNEL);
805 	if (!qca->rx_buffer)
806 		return -ENOBUFS;
807 
808 	qca->rx_skb = netdev_alloc_skb_ip_align(dev, qca->net_dev->mtu +
809 						VLAN_ETH_HLEN);
810 	if (!qca->rx_skb) {
811 		kfree(qca->rx_buffer);
812 		netdev_info(qca->net_dev, "Failed to allocate RX sk_buff.\n");
813 		return -ENOBUFS;
814 	}
815 
816 	return 0;
817 }
818 
819 static void
820 qcaspi_netdev_uninit(struct net_device *dev)
821 {
822 	struct qcaspi *qca = netdev_priv(dev);
823 
824 	kfree(qca->rx_buffer);
825 	qca->buffer_size = 0;
826 	if (qca->rx_skb)
827 		dev_kfree_skb(qca->rx_skb);
828 }
829 
830 static const struct net_device_ops qcaspi_netdev_ops = {
831 	.ndo_init = qcaspi_netdev_init,
832 	.ndo_uninit = qcaspi_netdev_uninit,
833 	.ndo_open = qcaspi_netdev_open,
834 	.ndo_stop = qcaspi_netdev_close,
835 	.ndo_start_xmit = qcaspi_netdev_xmit,
836 	.ndo_set_mac_address = eth_mac_addr,
837 	.ndo_tx_timeout = qcaspi_netdev_tx_timeout,
838 	.ndo_validate_addr = eth_validate_addr,
839 };
840 
841 static void
842 qcaspi_netdev_setup(struct net_device *dev)
843 {
844 	struct qcaspi *qca = NULL;
845 
846 	dev->netdev_ops = &qcaspi_netdev_ops;
847 	qcaspi_set_ethtool_ops(dev);
848 	dev->watchdog_timeo = QCASPI_TX_TIMEOUT;
849 	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
850 	dev->tx_queue_len = 100;
851 
852 	/* MTU range: 46 - 1500 */
853 	dev->min_mtu = QCAFRM_MIN_MTU;
854 	dev->max_mtu = QCAFRM_MAX_MTU;
855 
856 	qca = netdev_priv(dev);
857 	memset(qca, 0, sizeof(struct qcaspi));
858 
859 	memset(&qca->txr, 0, sizeof(qca->txr));
860 	qca->txr.count = TX_RING_MAX_LEN;
861 }
862 
863 static const struct of_device_id qca_spi_of_match[] = {
864 	{ .compatible = "qca,qca7000" },
865 	{ /* sentinel */ }
866 };
867 MODULE_DEVICE_TABLE(of, qca_spi_of_match);
868 
869 static int
870 qca_spi_probe(struct spi_device *spi)
871 {
872 	struct qcaspi *qca = NULL;
873 	struct net_device *qcaspi_devs = NULL;
874 	u8 legacy_mode = 0;
875 	u16 signature;
876 	const char *mac;
877 
878 	if (!spi->dev.of_node) {
879 		dev_err(&spi->dev, "Missing device tree\n");
880 		return -EINVAL;
881 	}
882 
883 	legacy_mode = of_property_read_bool(spi->dev.of_node,
884 					    "qca,legacy-mode");
885 
886 	if (qcaspi_clkspeed == 0) {
887 		if (spi->max_speed_hz)
888 			qcaspi_clkspeed = spi->max_speed_hz;
889 		else
890 			qcaspi_clkspeed = QCASPI_CLK_SPEED;
891 	}
892 
893 	if ((qcaspi_clkspeed < QCASPI_CLK_SPEED_MIN) ||
894 	    (qcaspi_clkspeed > QCASPI_CLK_SPEED_MAX)) {
895 		dev_err(&spi->dev, "Invalid clkspeed: %d\n",
896 			qcaspi_clkspeed);
897 		return -EINVAL;
898 	}
899 
900 	if ((qcaspi_burst_len < QCASPI_BURST_LEN_MIN) ||
901 	    (qcaspi_burst_len > QCASPI_BURST_LEN_MAX)) {
902 		dev_err(&spi->dev, "Invalid burst len: %d\n",
903 			qcaspi_burst_len);
904 		return -EINVAL;
905 	}
906 
907 	if ((qcaspi_pluggable < QCASPI_PLUGGABLE_MIN) ||
908 	    (qcaspi_pluggable > QCASPI_PLUGGABLE_MAX)) {
909 		dev_err(&spi->dev, "Invalid pluggable: %d\n",
910 			qcaspi_pluggable);
911 		return -EINVAL;
912 	}
913 
914 	if (wr_verify < QCASPI_WRITE_VERIFY_MIN ||
915 	    wr_verify > QCASPI_WRITE_VERIFY_MAX) {
916 		dev_err(&spi->dev, "Invalid write verify: %d\n",
917 			wr_verify);
918 		return -EINVAL;
919 	}
920 
921 	dev_info(&spi->dev, "ver=%s, clkspeed=%d, burst_len=%d, pluggable=%d\n",
922 		 QCASPI_DRV_VERSION,
923 		 qcaspi_clkspeed,
924 		 qcaspi_burst_len,
925 		 qcaspi_pluggable);
926 
927 	spi->mode = SPI_MODE_3;
928 	spi->max_speed_hz = qcaspi_clkspeed;
929 	if (spi_setup(spi) < 0) {
930 		dev_err(&spi->dev, "Unable to setup SPI device\n");
931 		return -EFAULT;
932 	}
933 
934 	qcaspi_devs = alloc_etherdev(sizeof(struct qcaspi));
935 	if (!qcaspi_devs)
936 		return -ENOMEM;
937 
938 	qcaspi_netdev_setup(qcaspi_devs);
939 	SET_NETDEV_DEV(qcaspi_devs, &spi->dev);
940 
941 	qca = netdev_priv(qcaspi_devs);
942 	if (!qca) {
943 		free_netdev(qcaspi_devs);
944 		dev_err(&spi->dev, "Fail to retrieve private structure\n");
945 		return -ENOMEM;
946 	}
947 	qca->net_dev = qcaspi_devs;
948 	qca->spi_dev = spi;
949 	qca->legacy_mode = legacy_mode;
950 
951 	spi_set_drvdata(spi, qcaspi_devs);
952 
953 	mac = of_get_mac_address(spi->dev.of_node);
954 
955 	if (mac)
956 		ether_addr_copy(qca->net_dev->dev_addr, mac);
957 
958 	if (!is_valid_ether_addr(qca->net_dev->dev_addr)) {
959 		eth_hw_addr_random(qca->net_dev);
960 		dev_info(&spi->dev, "Using random MAC address: %pM\n",
961 			 qca->net_dev->dev_addr);
962 	}
963 
964 	netif_carrier_off(qca->net_dev);
965 
966 	if (!qcaspi_pluggable) {
967 		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
968 		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
969 
970 		if (signature != QCASPI_GOOD_SIGNATURE) {
971 			dev_err(&spi->dev, "Invalid signature (0x%04X)\n",
972 				signature);
973 			free_netdev(qcaspi_devs);
974 			return -EFAULT;
975 		}
976 	}
977 
978 	if (register_netdev(qcaspi_devs)) {
979 		dev_err(&spi->dev, "Unable to register net device %s\n",
980 			qcaspi_devs->name);
981 		free_netdev(qcaspi_devs);
982 		return -EFAULT;
983 	}
984 
985 	qcaspi_init_device_debugfs(qca);
986 
987 	return 0;
988 }
989 
990 static int
991 qca_spi_remove(struct spi_device *spi)
992 {
993 	struct net_device *qcaspi_devs = spi_get_drvdata(spi);
994 	struct qcaspi *qca = netdev_priv(qcaspi_devs);
995 
996 	qcaspi_remove_device_debugfs(qca);
997 
998 	unregister_netdev(qcaspi_devs);
999 	free_netdev(qcaspi_devs);
1000 
1001 	return 0;
1002 }
1003 
1004 static const struct spi_device_id qca_spi_id[] = {
1005 	{ "qca7000", 0 },
1006 	{ /* sentinel */ }
1007 };
1008 MODULE_DEVICE_TABLE(spi, qca_spi_id);
1009 
1010 static struct spi_driver qca_spi_driver = {
1011 	.driver	= {
1012 		.name	= QCASPI_DRV_NAME,
1013 		.of_match_table = qca_spi_of_match,
1014 	},
1015 	.id_table = qca_spi_id,
1016 	.probe    = qca_spi_probe,
1017 	.remove   = qca_spi_remove,
1018 };
1019 module_spi_driver(qca_spi_driver);
1020 
1021 MODULE_DESCRIPTION("Qualcomm Atheros QCA7000 SPI Driver");
1022 MODULE_AUTHOR("Qualcomm Atheros Communications");
1023 MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
1024 MODULE_LICENSE("Dual BSD/GPL");
1025 MODULE_VERSION(QCASPI_DRV_VERSION);
1026