xref: /linux/drivers/net/ethernet/seeq/sgiseeq.c (revision 3932b9ca55b0be314a36d3e84faff3e823c081f5)
1 /*
2  * sgiseeq.c: Seeq8003 ethernet driver for SGI machines.
3  *
4  * Copyright (C) 1996 David S. Miller (davem@davemloft.net)
5  */
6 
7 #undef DEBUG
8 
9 #include <linux/dma-mapping.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/errno.h>
14 #include <linux/types.h>
15 #include <linux/interrupt.h>
16 #include <linux/string.h>
17 #include <linux/delay.h>
18 #include <linux/netdevice.h>
19 #include <linux/platform_device.h>
20 #include <linux/etherdevice.h>
21 #include <linux/skbuff.h>
22 
23 #include <asm/sgi/hpc3.h>
24 #include <asm/sgi/ip22.h>
25 #include <asm/sgi/seeq.h>
26 
27 #include "sgiseeq.h"
28 
29 static char *sgiseeqstr = "SGI Seeq8003";
30 
31 /*
32  * If you want speed, you do something silly, it always has worked for me.  So,
33  * with that in mind, I've decided to make this driver look completely like a
34  * stupid Lance from a driver architecture perspective.  Only difference is that
35  * here our "ring buffer" looks and acts like a real Lance one does but is
36  * laid out like how the HPC DMA and the Seeq want it to.  You'd be surprised
37  * how a stupid idea like this can pay off in performance, not to mention
38  * making this driver 2,000 times easier to write. ;-)
39  */
40 
41 /* Tune these if we tend to run out often etc. */
42 #define SEEQ_RX_BUFFERS  16
43 #define SEEQ_TX_BUFFERS  16
44 
45 #define PKT_BUF_SZ       1584
46 
47 #define NEXT_RX(i)  (((i) + 1) & (SEEQ_RX_BUFFERS - 1))
48 #define NEXT_TX(i)  (((i) + 1) & (SEEQ_TX_BUFFERS - 1))
49 #define PREV_RX(i)  (((i) - 1) & (SEEQ_RX_BUFFERS - 1))
50 #define PREV_TX(i)  (((i) - 1) & (SEEQ_TX_BUFFERS - 1))
51 
52 #define TX_BUFFS_AVAIL(sp) ((sp->tx_old <= sp->tx_new) ? \
53 			    sp->tx_old + (SEEQ_TX_BUFFERS - 1) - sp->tx_new : \
54 			    sp->tx_old - sp->tx_new - 1)
55 
56 #define VIRT_TO_DMA(sp, v) ((sp)->srings_dma +                                 \
57 				  (dma_addr_t)((unsigned long)(v) -            \
58 					       (unsigned long)((sp)->rx_desc)))
59 
60 /* Copy frames shorter than rx_copybreak, otherwise pass on up in
61  * a full sized sk_buff.  Value of 100 stolen from tulip.c (!alpha).
62  */
63 static int rx_copybreak = 100;
64 
65 #define PAD_SIZE    (128 - sizeof(struct hpc_dma_desc) - sizeof(void *))
66 
67 struct sgiseeq_rx_desc {
68 	volatile struct hpc_dma_desc rdma;
69 	u8 padding[PAD_SIZE];
70 	struct sk_buff *skb;
71 };
72 
73 struct sgiseeq_tx_desc {
74 	volatile struct hpc_dma_desc tdma;
75 	u8 padding[PAD_SIZE];
76 	struct sk_buff *skb;
77 };
78 
79 /*
80  * Warning: This structure is laid out in a certain way because HPC dma
81  *          descriptors must be 8-byte aligned.  So don't touch this without
82  *          some care.
83  */
84 struct sgiseeq_init_block { /* Note the name ;-) */
85 	struct sgiseeq_rx_desc rxvector[SEEQ_RX_BUFFERS];
86 	struct sgiseeq_tx_desc txvector[SEEQ_TX_BUFFERS];
87 };
88 
89 struct sgiseeq_private {
90 	struct sgiseeq_init_block *srings;
91 	dma_addr_t srings_dma;
92 
93 	/* Ptrs to the descriptors in uncached space. */
94 	struct sgiseeq_rx_desc *rx_desc;
95 	struct sgiseeq_tx_desc *tx_desc;
96 
97 	char *name;
98 	struct hpc3_ethregs *hregs;
99 	struct sgiseeq_regs *sregs;
100 
101 	/* Ring entry counters. */
102 	unsigned int rx_new, tx_new;
103 	unsigned int rx_old, tx_old;
104 
105 	int is_edlc;
106 	unsigned char control;
107 	unsigned char mode;
108 
109 	spinlock_t tx_lock;
110 };
111 
112 static inline void dma_sync_desc_cpu(struct net_device *dev, void *addr)
113 {
114 	dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc),
115 		       DMA_FROM_DEVICE);
116 }
117 
118 static inline void dma_sync_desc_dev(struct net_device *dev, void *addr)
119 {
120 	dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc),
121 		       DMA_TO_DEVICE);
122 }
123 
124 static inline void hpc3_eth_reset(struct hpc3_ethregs *hregs)
125 {
126 	hregs->reset = HPC3_ERST_CRESET | HPC3_ERST_CLRIRQ;
127 	udelay(20);
128 	hregs->reset = 0;
129 }
130 
131 static inline void reset_hpc3_and_seeq(struct hpc3_ethregs *hregs,
132 				       struct sgiseeq_regs *sregs)
133 {
134 	hregs->rx_ctrl = hregs->tx_ctrl = 0;
135 	hpc3_eth_reset(hregs);
136 }
137 
138 #define RSTAT_GO_BITS (SEEQ_RCMD_IGOOD | SEEQ_RCMD_IEOF | SEEQ_RCMD_ISHORT | \
139 		       SEEQ_RCMD_IDRIB | SEEQ_RCMD_ICRC)
140 
141 static inline void seeq_go(struct sgiseeq_private *sp,
142 			   struct hpc3_ethregs *hregs,
143 			   struct sgiseeq_regs *sregs)
144 {
145 	sregs->rstat = sp->mode | RSTAT_GO_BITS;
146 	hregs->rx_ctrl = HPC3_ERXCTRL_ACTIVE;
147 }
148 
149 static inline void __sgiseeq_set_mac_address(struct net_device *dev)
150 {
151 	struct sgiseeq_private *sp = netdev_priv(dev);
152 	struct sgiseeq_regs *sregs = sp->sregs;
153 	int i;
154 
155 	sregs->tstat = SEEQ_TCMD_RB0;
156 	for (i = 0; i < 6; i++)
157 		sregs->rw.eth_addr[i] = dev->dev_addr[i];
158 }
159 
160 static int sgiseeq_set_mac_address(struct net_device *dev, void *addr)
161 {
162 	struct sgiseeq_private *sp = netdev_priv(dev);
163 	struct sockaddr *sa = addr;
164 
165 	memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
166 
167 	spin_lock_irq(&sp->tx_lock);
168 	__sgiseeq_set_mac_address(dev);
169 	spin_unlock_irq(&sp->tx_lock);
170 
171 	return 0;
172 }
173 
174 #define TCNTINFO_INIT (HPCDMA_EOX | HPCDMA_ETXD)
175 #define RCNTCFG_INIT  (HPCDMA_OWN | HPCDMA_EORP | HPCDMA_XIE)
176 #define RCNTINFO_INIT (RCNTCFG_INIT | (PKT_BUF_SZ & HPCDMA_BCNT))
177 
178 static int seeq_init_ring(struct net_device *dev)
179 {
180 	struct sgiseeq_private *sp = netdev_priv(dev);
181 	int i;
182 
183 	netif_stop_queue(dev);
184 	sp->rx_new = sp->tx_new = 0;
185 	sp->rx_old = sp->tx_old = 0;
186 
187 	__sgiseeq_set_mac_address(dev);
188 
189 	/* Setup tx ring. */
190 	for(i = 0; i < SEEQ_TX_BUFFERS; i++) {
191 		sp->tx_desc[i].tdma.cntinfo = TCNTINFO_INIT;
192 		dma_sync_desc_dev(dev, &sp->tx_desc[i]);
193 	}
194 
195 	/* And now the rx ring. */
196 	for (i = 0; i < SEEQ_RX_BUFFERS; i++) {
197 		if (!sp->rx_desc[i].skb) {
198 			dma_addr_t dma_addr;
199 			struct sk_buff *skb = netdev_alloc_skb(dev, PKT_BUF_SZ);
200 
201 			if (skb == NULL)
202 				return -ENOMEM;
203 			skb_reserve(skb, 2);
204 			dma_addr = dma_map_single(dev->dev.parent,
205 						  skb->data - 2,
206 						  PKT_BUF_SZ, DMA_FROM_DEVICE);
207 			sp->rx_desc[i].skb = skb;
208 			sp->rx_desc[i].rdma.pbuf = dma_addr;
209 		}
210 		sp->rx_desc[i].rdma.cntinfo = RCNTINFO_INIT;
211 		dma_sync_desc_dev(dev, &sp->rx_desc[i]);
212 	}
213 	sp->rx_desc[i - 1].rdma.cntinfo |= HPCDMA_EOR;
214 	dma_sync_desc_dev(dev, &sp->rx_desc[i - 1]);
215 	return 0;
216 }
217 
218 static void seeq_purge_ring(struct net_device *dev)
219 {
220 	struct sgiseeq_private *sp = netdev_priv(dev);
221 	int i;
222 
223 	/* clear tx ring. */
224 	for (i = 0; i < SEEQ_TX_BUFFERS; i++) {
225 		if (sp->tx_desc[i].skb) {
226 			dev_kfree_skb(sp->tx_desc[i].skb);
227 			sp->tx_desc[i].skb = NULL;
228 		}
229 	}
230 
231 	/* And now the rx ring. */
232 	for (i = 0; i < SEEQ_RX_BUFFERS; i++) {
233 		if (sp->rx_desc[i].skb) {
234 			dev_kfree_skb(sp->rx_desc[i].skb);
235 			sp->rx_desc[i].skb = NULL;
236 		}
237 	}
238 }
239 
240 #ifdef DEBUG
241 static struct sgiseeq_private *gpriv;
242 static struct net_device *gdev;
243 
244 static void sgiseeq_dump_rings(void)
245 {
246 	static int once;
247 	struct sgiseeq_rx_desc *r = gpriv->rx_desc;
248 	struct sgiseeq_tx_desc *t = gpriv->tx_desc;
249 	struct hpc3_ethregs *hregs = gpriv->hregs;
250 	int i;
251 
252 	if (once)
253 		return;
254 	once++;
255 	printk("RING DUMP:\n");
256 	for (i = 0; i < SEEQ_RX_BUFFERS; i++) {
257 		printk("RX [%d]: @(%p) [%08x,%08x,%08x] ",
258 		       i, (&r[i]), r[i].rdma.pbuf, r[i].rdma.cntinfo,
259 		       r[i].rdma.pnext);
260 		i += 1;
261 		printk("-- [%d]: @(%p) [%08x,%08x,%08x]\n",
262 		       i, (&r[i]), r[i].rdma.pbuf, r[i].rdma.cntinfo,
263 		       r[i].rdma.pnext);
264 	}
265 	for (i = 0; i < SEEQ_TX_BUFFERS; i++) {
266 		printk("TX [%d]: @(%p) [%08x,%08x,%08x] ",
267 		       i, (&t[i]), t[i].tdma.pbuf, t[i].tdma.cntinfo,
268 		       t[i].tdma.pnext);
269 		i += 1;
270 		printk("-- [%d]: @(%p) [%08x,%08x,%08x]\n",
271 		       i, (&t[i]), t[i].tdma.pbuf, t[i].tdma.cntinfo,
272 		       t[i].tdma.pnext);
273 	}
274 	printk("INFO: [rx_new = %d rx_old=%d] [tx_new = %d tx_old = %d]\n",
275 	       gpriv->rx_new, gpriv->rx_old, gpriv->tx_new, gpriv->tx_old);
276 	printk("RREGS: rx_cbptr[%08x] rx_ndptr[%08x] rx_ctrl[%08x]\n",
277 	       hregs->rx_cbptr, hregs->rx_ndptr, hregs->rx_ctrl);
278 	printk("TREGS: tx_cbptr[%08x] tx_ndptr[%08x] tx_ctrl[%08x]\n",
279 	       hregs->tx_cbptr, hregs->tx_ndptr, hregs->tx_ctrl);
280 }
281 #endif
282 
283 #define TSTAT_INIT_SEEQ (SEEQ_TCMD_IPT|SEEQ_TCMD_I16|SEEQ_TCMD_IC|SEEQ_TCMD_IUF)
284 #define TSTAT_INIT_EDLC ((TSTAT_INIT_SEEQ) | SEEQ_TCMD_RB2)
285 
286 static int init_seeq(struct net_device *dev, struct sgiseeq_private *sp,
287 		     struct sgiseeq_regs *sregs)
288 {
289 	struct hpc3_ethregs *hregs = sp->hregs;
290 	int err;
291 
292 	reset_hpc3_and_seeq(hregs, sregs);
293 	err = seeq_init_ring(dev);
294 	if (err)
295 		return err;
296 
297 	/* Setup to field the proper interrupt types. */
298 	if (sp->is_edlc) {
299 		sregs->tstat = TSTAT_INIT_EDLC;
300 		sregs->rw.wregs.control = sp->control;
301 		sregs->rw.wregs.frame_gap = 0;
302 	} else {
303 		sregs->tstat = TSTAT_INIT_SEEQ;
304 	}
305 
306 	hregs->rx_ndptr = VIRT_TO_DMA(sp, sp->rx_desc);
307 	hregs->tx_ndptr = VIRT_TO_DMA(sp, sp->tx_desc);
308 
309 	seeq_go(sp, hregs, sregs);
310 	return 0;
311 }
312 
313 static void record_rx_errors(struct net_device *dev, unsigned char status)
314 {
315 	if (status & SEEQ_RSTAT_OVERF ||
316 	    status & SEEQ_RSTAT_SFRAME)
317 		dev->stats.rx_over_errors++;
318 	if (status & SEEQ_RSTAT_CERROR)
319 		dev->stats.rx_crc_errors++;
320 	if (status & SEEQ_RSTAT_DERROR)
321 		dev->stats.rx_frame_errors++;
322 	if (status & SEEQ_RSTAT_REOF)
323 		dev->stats.rx_errors++;
324 }
325 
326 static inline void rx_maybe_restart(struct sgiseeq_private *sp,
327 				    struct hpc3_ethregs *hregs,
328 				    struct sgiseeq_regs *sregs)
329 {
330 	if (!(hregs->rx_ctrl & HPC3_ERXCTRL_ACTIVE)) {
331 		hregs->rx_ndptr = VIRT_TO_DMA(sp, sp->rx_desc + sp->rx_new);
332 		seeq_go(sp, hregs, sregs);
333 	}
334 }
335 
336 static inline void sgiseeq_rx(struct net_device *dev, struct sgiseeq_private *sp,
337 			      struct hpc3_ethregs *hregs,
338 			      struct sgiseeq_regs *sregs)
339 {
340 	struct sgiseeq_rx_desc *rd;
341 	struct sk_buff *skb = NULL;
342 	struct sk_buff *newskb;
343 	unsigned char pkt_status;
344 	int len = 0;
345 	unsigned int orig_end = PREV_RX(sp->rx_new);
346 
347 	/* Service every received packet. */
348 	rd = &sp->rx_desc[sp->rx_new];
349 	dma_sync_desc_cpu(dev, rd);
350 	while (!(rd->rdma.cntinfo & HPCDMA_OWN)) {
351 		len = PKT_BUF_SZ - (rd->rdma.cntinfo & HPCDMA_BCNT) - 3;
352 		dma_unmap_single(dev->dev.parent, rd->rdma.pbuf,
353 				 PKT_BUF_SZ, DMA_FROM_DEVICE);
354 		pkt_status = rd->skb->data[len];
355 		if (pkt_status & SEEQ_RSTAT_FIG) {
356 			/* Packet is OK. */
357 			/* We don't want to receive our own packets */
358 			if (!ether_addr_equal(rd->skb->data + 6, dev->dev_addr)) {
359 				if (len > rx_copybreak) {
360 					skb = rd->skb;
361 					newskb = netdev_alloc_skb(dev, PKT_BUF_SZ);
362 					if (!newskb) {
363 						newskb = skb;
364 						skb = NULL;
365 						goto memory_squeeze;
366 					}
367 					skb_reserve(newskb, 2);
368 				} else {
369 					skb = netdev_alloc_skb_ip_align(dev, len);
370 					if (skb)
371 						skb_copy_to_linear_data(skb, rd->skb->data, len);
372 
373 					newskb = rd->skb;
374 				}
375 memory_squeeze:
376 				if (skb) {
377 					skb_put(skb, len);
378 					skb->protocol = eth_type_trans(skb, dev);
379 					netif_rx(skb);
380 					dev->stats.rx_packets++;
381 					dev->stats.rx_bytes += len;
382 				} else {
383 					dev->stats.rx_dropped++;
384 				}
385 			} else {
386 				/* Silently drop my own packets */
387 				newskb = rd->skb;
388 			}
389 		} else {
390 			record_rx_errors(dev, pkt_status);
391 			newskb = rd->skb;
392 		}
393 		rd->skb = newskb;
394 		rd->rdma.pbuf = dma_map_single(dev->dev.parent,
395 					       newskb->data - 2,
396 					       PKT_BUF_SZ, DMA_FROM_DEVICE);
397 
398 		/* Return the entry to the ring pool. */
399 		rd->rdma.cntinfo = RCNTINFO_INIT;
400 		sp->rx_new = NEXT_RX(sp->rx_new);
401 		dma_sync_desc_dev(dev, rd);
402 		rd = &sp->rx_desc[sp->rx_new];
403 		dma_sync_desc_cpu(dev, rd);
404 	}
405 	dma_sync_desc_cpu(dev, &sp->rx_desc[orig_end]);
406 	sp->rx_desc[orig_end].rdma.cntinfo &= ~(HPCDMA_EOR);
407 	dma_sync_desc_dev(dev, &sp->rx_desc[orig_end]);
408 	dma_sync_desc_cpu(dev, &sp->rx_desc[PREV_RX(sp->rx_new)]);
409 	sp->rx_desc[PREV_RX(sp->rx_new)].rdma.cntinfo |= HPCDMA_EOR;
410 	dma_sync_desc_dev(dev, &sp->rx_desc[PREV_RX(sp->rx_new)]);
411 	rx_maybe_restart(sp, hregs, sregs);
412 }
413 
414 static inline void tx_maybe_reset_collisions(struct sgiseeq_private *sp,
415 					     struct sgiseeq_regs *sregs)
416 {
417 	if (sp->is_edlc) {
418 		sregs->rw.wregs.control = sp->control & ~(SEEQ_CTRL_XCNT);
419 		sregs->rw.wregs.control = sp->control;
420 	}
421 }
422 
423 static inline void kick_tx(struct net_device *dev,
424 			   struct sgiseeq_private *sp,
425 			   struct hpc3_ethregs *hregs)
426 {
427 	struct sgiseeq_tx_desc *td;
428 	int i = sp->tx_old;
429 
430 	/* If the HPC aint doin nothin, and there are more packets
431 	 * with ETXD cleared and XIU set we must make very certain
432 	 * that we restart the HPC else we risk locking up the
433 	 * adapter.  The following code is only safe iff the HPCDMA
434 	 * is not active!
435 	 */
436 	td = &sp->tx_desc[i];
437 	dma_sync_desc_cpu(dev, td);
438 	while ((td->tdma.cntinfo & (HPCDMA_XIU | HPCDMA_ETXD)) ==
439 	      (HPCDMA_XIU | HPCDMA_ETXD)) {
440 		i = NEXT_TX(i);
441 		td = &sp->tx_desc[i];
442 		dma_sync_desc_cpu(dev, td);
443 	}
444 	if (td->tdma.cntinfo & HPCDMA_XIU) {
445 		hregs->tx_ndptr = VIRT_TO_DMA(sp, td);
446 		hregs->tx_ctrl = HPC3_ETXCTRL_ACTIVE;
447 	}
448 }
449 
450 static inline void sgiseeq_tx(struct net_device *dev, struct sgiseeq_private *sp,
451 			      struct hpc3_ethregs *hregs,
452 			      struct sgiseeq_regs *sregs)
453 {
454 	struct sgiseeq_tx_desc *td;
455 	unsigned long status = hregs->tx_ctrl;
456 	int j;
457 
458 	tx_maybe_reset_collisions(sp, sregs);
459 
460 	if (!(status & (HPC3_ETXCTRL_ACTIVE | SEEQ_TSTAT_PTRANS))) {
461 		/* Oops, HPC detected some sort of error. */
462 		if (status & SEEQ_TSTAT_R16)
463 			dev->stats.tx_aborted_errors++;
464 		if (status & SEEQ_TSTAT_UFLOW)
465 			dev->stats.tx_fifo_errors++;
466 		if (status & SEEQ_TSTAT_LCLS)
467 			dev->stats.collisions++;
468 	}
469 
470 	/* Ack 'em... */
471 	for (j = sp->tx_old; j != sp->tx_new; j = NEXT_TX(j)) {
472 		td = &sp->tx_desc[j];
473 
474 		dma_sync_desc_cpu(dev, td);
475 		if (!(td->tdma.cntinfo & (HPCDMA_XIU)))
476 			break;
477 		if (!(td->tdma.cntinfo & (HPCDMA_ETXD))) {
478 			if (!(status & HPC3_ETXCTRL_ACTIVE)) {
479 				hregs->tx_ndptr = VIRT_TO_DMA(sp, td);
480 				hregs->tx_ctrl = HPC3_ETXCTRL_ACTIVE;
481 			}
482 			break;
483 		}
484 		dev->stats.tx_packets++;
485 		sp->tx_old = NEXT_TX(sp->tx_old);
486 		td->tdma.cntinfo &= ~(HPCDMA_XIU | HPCDMA_XIE);
487 		td->tdma.cntinfo |= HPCDMA_EOX;
488 		if (td->skb) {
489 			dev_kfree_skb_any(td->skb);
490 			td->skb = NULL;
491 		}
492 		dma_sync_desc_dev(dev, td);
493 	}
494 }
495 
496 static irqreturn_t sgiseeq_interrupt(int irq, void *dev_id)
497 {
498 	struct net_device *dev = (struct net_device *) dev_id;
499 	struct sgiseeq_private *sp = netdev_priv(dev);
500 	struct hpc3_ethregs *hregs = sp->hregs;
501 	struct sgiseeq_regs *sregs = sp->sregs;
502 
503 	spin_lock(&sp->tx_lock);
504 
505 	/* Ack the IRQ and set software state. */
506 	hregs->reset = HPC3_ERST_CLRIRQ;
507 
508 	/* Always check for received packets. */
509 	sgiseeq_rx(dev, sp, hregs, sregs);
510 
511 	/* Only check for tx acks if we have something queued. */
512 	if (sp->tx_old != sp->tx_new)
513 		sgiseeq_tx(dev, sp, hregs, sregs);
514 
515 	if ((TX_BUFFS_AVAIL(sp) > 0) && netif_queue_stopped(dev)) {
516 		netif_wake_queue(dev);
517 	}
518 	spin_unlock(&sp->tx_lock);
519 
520 	return IRQ_HANDLED;
521 }
522 
523 static int sgiseeq_open(struct net_device *dev)
524 {
525 	struct sgiseeq_private *sp = netdev_priv(dev);
526 	struct sgiseeq_regs *sregs = sp->sregs;
527 	unsigned int irq = dev->irq;
528 	int err;
529 
530 	if (request_irq(irq, sgiseeq_interrupt, 0, sgiseeqstr, dev)) {
531 		printk(KERN_ERR "Seeq8003: Can't get irq %d\n", dev->irq);
532 		return -EAGAIN;
533 	}
534 
535 	err = init_seeq(dev, sp, sregs);
536 	if (err)
537 		goto out_free_irq;
538 
539 	netif_start_queue(dev);
540 
541 	return 0;
542 
543 out_free_irq:
544 	free_irq(irq, dev);
545 
546 	return err;
547 }
548 
549 static int sgiseeq_close(struct net_device *dev)
550 {
551 	struct sgiseeq_private *sp = netdev_priv(dev);
552 	struct sgiseeq_regs *sregs = sp->sregs;
553 	unsigned int irq = dev->irq;
554 
555 	netif_stop_queue(dev);
556 
557 	/* Shutdown the Seeq. */
558 	reset_hpc3_and_seeq(sp->hregs, sregs);
559 	free_irq(irq, dev);
560 	seeq_purge_ring(dev);
561 
562 	return 0;
563 }
564 
565 static inline int sgiseeq_reset(struct net_device *dev)
566 {
567 	struct sgiseeq_private *sp = netdev_priv(dev);
568 	struct sgiseeq_regs *sregs = sp->sregs;
569 	int err;
570 
571 	err = init_seeq(dev, sp, sregs);
572 	if (err)
573 		return err;
574 
575 	dev->trans_start = jiffies; /* prevent tx timeout */
576 	netif_wake_queue(dev);
577 
578 	return 0;
579 }
580 
581 static int sgiseeq_start_xmit(struct sk_buff *skb, struct net_device *dev)
582 {
583 	struct sgiseeq_private *sp = netdev_priv(dev);
584 	struct hpc3_ethregs *hregs = sp->hregs;
585 	unsigned long flags;
586 	struct sgiseeq_tx_desc *td;
587 	int len, entry;
588 
589 	spin_lock_irqsave(&sp->tx_lock, flags);
590 
591 	/* Setup... */
592 	len = skb->len;
593 	if (len < ETH_ZLEN) {
594 		if (skb_padto(skb, ETH_ZLEN)) {
595 			spin_unlock_irqrestore(&sp->tx_lock, flags);
596 			return NETDEV_TX_OK;
597 		}
598 		len = ETH_ZLEN;
599 	}
600 
601 	dev->stats.tx_bytes += len;
602 	entry = sp->tx_new;
603 	td = &sp->tx_desc[entry];
604 	dma_sync_desc_cpu(dev, td);
605 
606 	/* Create entry.  There are so many races with adding a new
607 	 * descriptor to the chain:
608 	 * 1) Assume that the HPC is off processing a DMA chain while
609 	 *    we are changing all of the following.
610 	 * 2) Do no allow the HPC to look at a new descriptor until
611 	 *    we have completely set up it's state.  This means, do
612 	 *    not clear HPCDMA_EOX in the current last descritptor
613 	 *    until the one we are adding looks consistent and could
614 	 *    be processes right now.
615 	 * 3) The tx interrupt code must notice when we've added a new
616 	 *    entry and the HPC got to the end of the chain before we
617 	 *    added this new entry and restarted it.
618 	 */
619 	td->skb = skb;
620 	td->tdma.pbuf = dma_map_single(dev->dev.parent, skb->data,
621 				       len, DMA_TO_DEVICE);
622 	td->tdma.cntinfo = (len & HPCDMA_BCNT) |
623 	                   HPCDMA_XIU | HPCDMA_EOXP | HPCDMA_XIE | HPCDMA_EOX;
624 	dma_sync_desc_dev(dev, td);
625 	if (sp->tx_old != sp->tx_new) {
626 		struct sgiseeq_tx_desc *backend;
627 
628 		backend = &sp->tx_desc[PREV_TX(sp->tx_new)];
629 		dma_sync_desc_cpu(dev, backend);
630 		backend->tdma.cntinfo &= ~HPCDMA_EOX;
631 		dma_sync_desc_dev(dev, backend);
632 	}
633 	sp->tx_new = NEXT_TX(sp->tx_new); /* Advance. */
634 
635 	/* Maybe kick the HPC back into motion. */
636 	if (!(hregs->tx_ctrl & HPC3_ETXCTRL_ACTIVE))
637 		kick_tx(dev, sp, hregs);
638 
639 	if (!TX_BUFFS_AVAIL(sp))
640 		netif_stop_queue(dev);
641 	spin_unlock_irqrestore(&sp->tx_lock, flags);
642 
643 	return NETDEV_TX_OK;
644 }
645 
646 static void timeout(struct net_device *dev)
647 {
648 	printk(KERN_NOTICE "%s: transmit timed out, resetting\n", dev->name);
649 	sgiseeq_reset(dev);
650 
651 	dev->trans_start = jiffies; /* prevent tx timeout */
652 	netif_wake_queue(dev);
653 }
654 
655 static void sgiseeq_set_multicast(struct net_device *dev)
656 {
657 	struct sgiseeq_private *sp = netdev_priv(dev);
658 	unsigned char oldmode = sp->mode;
659 
660 	if(dev->flags & IFF_PROMISC)
661 		sp->mode = SEEQ_RCMD_RANY;
662 	else if ((dev->flags & IFF_ALLMULTI) || !netdev_mc_empty(dev))
663 		sp->mode = SEEQ_RCMD_RBMCAST;
664 	else
665 		sp->mode = SEEQ_RCMD_RBCAST;
666 
667 	/* XXX I know this sucks, but is there a better way to reprogram
668 	 * XXX the receiver? At least, this shouldn't happen too often.
669 	 */
670 
671 	if (oldmode != sp->mode)
672 		sgiseeq_reset(dev);
673 }
674 
675 static inline void setup_tx_ring(struct net_device *dev,
676 				 struct sgiseeq_tx_desc *buf,
677 				 int nbufs)
678 {
679 	struct sgiseeq_private *sp = netdev_priv(dev);
680 	int i = 0;
681 
682 	while (i < (nbufs - 1)) {
683 		buf[i].tdma.pnext = VIRT_TO_DMA(sp, buf + i + 1);
684 		buf[i].tdma.pbuf = 0;
685 		dma_sync_desc_dev(dev, &buf[i]);
686 		i++;
687 	}
688 	buf[i].tdma.pnext = VIRT_TO_DMA(sp, buf);
689 	dma_sync_desc_dev(dev, &buf[i]);
690 }
691 
692 static inline void setup_rx_ring(struct net_device *dev,
693 				 struct sgiseeq_rx_desc *buf,
694 				 int nbufs)
695 {
696 	struct sgiseeq_private *sp = netdev_priv(dev);
697 	int i = 0;
698 
699 	while (i < (nbufs - 1)) {
700 		buf[i].rdma.pnext = VIRT_TO_DMA(sp, buf + i + 1);
701 		buf[i].rdma.pbuf = 0;
702 		dma_sync_desc_dev(dev, &buf[i]);
703 		i++;
704 	}
705 	buf[i].rdma.pbuf = 0;
706 	buf[i].rdma.pnext = VIRT_TO_DMA(sp, buf);
707 	dma_sync_desc_dev(dev, &buf[i]);
708 }
709 
710 static const struct net_device_ops sgiseeq_netdev_ops = {
711 	.ndo_open		= sgiseeq_open,
712 	.ndo_stop		= sgiseeq_close,
713 	.ndo_start_xmit		= sgiseeq_start_xmit,
714 	.ndo_tx_timeout		= timeout,
715 	.ndo_set_rx_mode	= sgiseeq_set_multicast,
716 	.ndo_set_mac_address	= sgiseeq_set_mac_address,
717 	.ndo_change_mtu		= eth_change_mtu,
718 	.ndo_validate_addr	= eth_validate_addr,
719 };
720 
721 static int sgiseeq_probe(struct platform_device *pdev)
722 {
723 	struct sgiseeq_platform_data *pd = dev_get_platdata(&pdev->dev);
724 	struct hpc3_regs *hpcregs = pd->hpc;
725 	struct sgiseeq_init_block *sr;
726 	unsigned int irq = pd->irq;
727 	struct sgiseeq_private *sp;
728 	struct net_device *dev;
729 	int err;
730 
731 	dev = alloc_etherdev(sizeof (struct sgiseeq_private));
732 	if (!dev) {
733 		err = -ENOMEM;
734 		goto err_out;
735 	}
736 
737 	platform_set_drvdata(pdev, dev);
738 	sp = netdev_priv(dev);
739 
740 	/* Make private data page aligned */
741 	sr = dma_alloc_noncoherent(&pdev->dev, sizeof(*sp->srings),
742 				&sp->srings_dma, GFP_KERNEL);
743 	if (!sr) {
744 		printk(KERN_ERR "Sgiseeq: Page alloc failed, aborting.\n");
745 		err = -ENOMEM;
746 		goto err_out_free_dev;
747 	}
748 	sp->srings = sr;
749 	sp->rx_desc = sp->srings->rxvector;
750 	sp->tx_desc = sp->srings->txvector;
751 	spin_lock_init(&sp->tx_lock);
752 
753 	/* A couple calculations now, saves many cycles later. */
754 	setup_rx_ring(dev, sp->rx_desc, SEEQ_RX_BUFFERS);
755 	setup_tx_ring(dev, sp->tx_desc, SEEQ_TX_BUFFERS);
756 
757 	memcpy(dev->dev_addr, pd->mac, ETH_ALEN);
758 
759 #ifdef DEBUG
760 	gpriv = sp;
761 	gdev = dev;
762 #endif
763 	sp->sregs = (struct sgiseeq_regs *) &hpcregs->eth_ext[0];
764 	sp->hregs = &hpcregs->ethregs;
765 	sp->name = sgiseeqstr;
766 	sp->mode = SEEQ_RCMD_RBCAST;
767 
768 	/* Setup PIO and DMA transfer timing */
769 	sp->hregs->pconfig = 0x161;
770 	sp->hregs->dconfig = HPC3_EDCFG_FIRQ | HPC3_EDCFG_FEOP |
771 			     HPC3_EDCFG_FRXDC | HPC3_EDCFG_PTO | 0x026;
772 
773 	/* Setup PIO and DMA transfer timing */
774 	sp->hregs->pconfig = 0x161;
775 	sp->hregs->dconfig = HPC3_EDCFG_FIRQ | HPC3_EDCFG_FEOP |
776 			     HPC3_EDCFG_FRXDC | HPC3_EDCFG_PTO | 0x026;
777 
778 	/* Reset the chip. */
779 	hpc3_eth_reset(sp->hregs);
780 
781 	sp->is_edlc = !(sp->sregs->rw.rregs.collision_tx[0] & 0xff);
782 	if (sp->is_edlc)
783 		sp->control = SEEQ_CTRL_XCNT | SEEQ_CTRL_ACCNT |
784 			      SEEQ_CTRL_SFLAG | SEEQ_CTRL_ESHORT |
785 			      SEEQ_CTRL_ENCARR;
786 
787 	dev->netdev_ops		= &sgiseeq_netdev_ops;
788 	dev->watchdog_timeo	= (200 * HZ) / 1000;
789 	dev->irq		= irq;
790 
791 	if (register_netdev(dev)) {
792 		printk(KERN_ERR "Sgiseeq: Cannot register net device, "
793 		       "aborting.\n");
794 		err = -ENODEV;
795 		goto err_out_free_page;
796 	}
797 
798 	printk(KERN_INFO "%s: %s %pM\n", dev->name, sgiseeqstr, dev->dev_addr);
799 
800 	return 0;
801 
802 err_out_free_page:
803 	free_page((unsigned long) sp->srings);
804 err_out_free_dev:
805 	free_netdev(dev);
806 
807 err_out:
808 	return err;
809 }
810 
811 static int __exit sgiseeq_remove(struct platform_device *pdev)
812 {
813 	struct net_device *dev = platform_get_drvdata(pdev);
814 	struct sgiseeq_private *sp = netdev_priv(dev);
815 
816 	unregister_netdev(dev);
817 	dma_free_noncoherent(&pdev->dev, sizeof(*sp->srings), sp->srings,
818 			     sp->srings_dma);
819 	free_netdev(dev);
820 
821 	return 0;
822 }
823 
824 static struct platform_driver sgiseeq_driver = {
825 	.probe	= sgiseeq_probe,
826 	.remove	= __exit_p(sgiseeq_remove),
827 	.driver = {
828 		.name	= "sgiseeq",
829 		.owner	= THIS_MODULE,
830 	}
831 };
832 
833 module_platform_driver(sgiseeq_driver);
834 
835 MODULE_DESCRIPTION("SGI Seeq 8003 driver");
836 MODULE_AUTHOR("Linux/MIPS Mailing List <linux-mips@linux-mips.org>");
837 MODULE_LICENSE("GPL");
838 MODULE_ALIAS("platform:sgiseeq");
839