xref: /linux/drivers/net/ethernet/sgi/meth.c (revision 827634added7f38b7d724cab1dccdb2b004c13c3)
1 /*
2  * meth.c -- O2 Builtin 10/100 Ethernet driver
3  *
4  * Copyright (C) 2001-2003 Ilya Volynets
5  *
6  *	This program is free software; you can redistribute it and/or
7  *	modify it under the terms of the GNU General Public License
8  *	as published by the Free Software Foundation; either version
9  *	2 of the License, or (at your option) any later version.
10  */
11 #include <linux/delay.h>
12 #include <linux/dma-mapping.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/slab.h>
17 #include <linux/errno.h>
18 #include <linux/types.h>
19 #include <linux/interrupt.h>
20 
21 #include <linux/in.h>
22 #include <linux/in6.h>
23 #include <linux/device.h> /* struct device, et al */
24 #include <linux/netdevice.h>   /* struct device, and other headers */
25 #include <linux/etherdevice.h> /* eth_type_trans */
26 #include <linux/ip.h>          /* struct iphdr */
27 #include <linux/tcp.h>         /* struct tcphdr */
28 #include <linux/skbuff.h>
29 #include <linux/mii.h>         /* MII definitions */
30 #include <linux/crc32.h>
31 
32 #include <asm/ip32/mace.h>
33 #include <asm/ip32/ip32_ints.h>
34 
35 #include <asm/io.h>
36 
37 #include "meth.h"
38 
39 #ifndef MFE_DEBUG
40 #define MFE_DEBUG 0
41 #endif
42 
43 #if MFE_DEBUG>=1
44 #define DPRINTK(str,args...) printk(KERN_DEBUG "meth: %s: " str, __func__ , ## args)
45 #define MFE_RX_DEBUG 2
46 #else
47 #define DPRINTK(str,args...)
48 #define MFE_RX_DEBUG 0
49 #endif
50 
51 
52 static const char *meth_str="SGI O2 Fast Ethernet";
53 
54 /* The maximum time waited (in jiffies) before assuming a Tx failed. (400ms) */
55 #define TX_TIMEOUT (400*HZ/1000)
56 
57 static int timeout = TX_TIMEOUT;
58 module_param(timeout, int, 0);
59 
60 /*
61  * Maximum number of multicast addresses to filter (vs. Rx-all-multicast).
62  * MACE Ethernet uses a 64 element hash table based on the Ethernet CRC.
63  */
64 #define METH_MCF_LIMIT 32
65 
66 /*
67  * This structure is private to each device. It is used to pass
68  * packets in and out, so there is place for a packet
69  */
70 struct meth_private {
71 	/* in-memory copy of MAC Control register */
72 	u64 mac_ctrl;
73 
74 	/* in-memory copy of DMA Control register */
75 	unsigned long dma_ctrl;
76 	/* address of PHY, used by mdio_* functions, initialized in mdio_probe */
77 	unsigned long phy_addr;
78 	tx_packet *tx_ring;
79 	dma_addr_t tx_ring_dma;
80 	struct sk_buff *tx_skbs[TX_RING_ENTRIES];
81 	dma_addr_t tx_skb_dmas[TX_RING_ENTRIES];
82 	unsigned long tx_read, tx_write, tx_count;
83 
84 	rx_packet *rx_ring[RX_RING_ENTRIES];
85 	dma_addr_t rx_ring_dmas[RX_RING_ENTRIES];
86 	struct sk_buff *rx_skbs[RX_RING_ENTRIES];
87 	unsigned long rx_write;
88 
89 	/* Multicast filter. */
90 	u64 mcast_filter;
91 
92 	spinlock_t meth_lock;
93 };
94 
95 static void meth_tx_timeout(struct net_device *dev);
96 static irqreturn_t meth_interrupt(int irq, void *dev_id);
97 
98 /* global, initialized in ip32-setup.c */
99 char o2meth_eaddr[8]={0,0,0,0,0,0,0,0};
100 
101 static inline void load_eaddr(struct net_device *dev)
102 {
103 	int i;
104 	u64 macaddr;
105 
106 	DPRINTK("Loading MAC Address: %pM\n", dev->dev_addr);
107 	macaddr = 0;
108 	for (i = 0; i < 6; i++)
109 		macaddr |= (u64)dev->dev_addr[i] << ((5 - i) * 8);
110 
111 	mace->eth.mac_addr = macaddr;
112 }
113 
114 /*
115  * Waits for BUSY status of mdio bus to clear
116  */
117 #define WAIT_FOR_PHY(___rval)					\
118 	while ((___rval = mace->eth.phy_data) & MDIO_BUSY) {	\
119 		udelay(25);					\
120 	}
121 /*read phy register, return value read */
122 static unsigned long mdio_read(struct meth_private *priv, unsigned long phyreg)
123 {
124 	unsigned long rval;
125 	WAIT_FOR_PHY(rval);
126 	mace->eth.phy_regs = (priv->phy_addr << 5) | (phyreg & 0x1f);
127 	udelay(25);
128 	mace->eth.phy_trans_go = 1;
129 	udelay(25);
130 	WAIT_FOR_PHY(rval);
131 	return rval & MDIO_DATA_MASK;
132 }
133 
134 static int mdio_probe(struct meth_private *priv)
135 {
136 	int i;
137 	unsigned long p2, p3, flags;
138 	/* check if phy is detected already */
139 	if(priv->phy_addr>=0&&priv->phy_addr<32)
140 		return 0;
141 	spin_lock_irqsave(&priv->meth_lock, flags);
142 	for (i=0;i<32;++i){
143 		priv->phy_addr=i;
144 		p2=mdio_read(priv,2);
145 		p3=mdio_read(priv,3);
146 #if MFE_DEBUG>=2
147 		switch ((p2<<12)|(p3>>4)){
148 		case PHY_QS6612X:
149 			DPRINTK("PHY is QS6612X\n");
150 			break;
151 		case PHY_ICS1889:
152 			DPRINTK("PHY is ICS1889\n");
153 			break;
154 		case PHY_ICS1890:
155 			DPRINTK("PHY is ICS1890\n");
156 			break;
157 		case PHY_DP83840:
158 			DPRINTK("PHY is DP83840\n");
159 			break;
160 		}
161 #endif
162 		if(p2!=0xffff&&p2!=0x0000){
163 			DPRINTK("PHY code: %x\n",(p2<<12)|(p3>>4));
164 			break;
165 		}
166 	}
167 	spin_unlock_irqrestore(&priv->meth_lock, flags);
168 	if(priv->phy_addr<32) {
169 		return 0;
170 	}
171 	DPRINTK("Oopsie! PHY is not known!\n");
172 	priv->phy_addr=-1;
173 	return -ENODEV;
174 }
175 
176 static void meth_check_link(struct net_device *dev)
177 {
178 	struct meth_private *priv = netdev_priv(dev);
179 	unsigned long mii_advertising = mdio_read(priv, 4);
180 	unsigned long mii_partner = mdio_read(priv, 5);
181 	unsigned long negotiated = mii_advertising & mii_partner;
182 	unsigned long duplex, speed;
183 
184 	if (mii_partner == 0xffff)
185 		return;
186 
187 	speed = (negotiated & 0x0380) ? METH_100MBIT : 0;
188 	duplex = ((negotiated & 0x0100) || (negotiated & 0x01C0) == 0x0040) ?
189 		 METH_PHY_FDX : 0;
190 
191 	if ((priv->mac_ctrl & METH_PHY_FDX) ^ duplex) {
192 		DPRINTK("Setting %s-duplex\n", duplex ? "full" : "half");
193 		if (duplex)
194 			priv->mac_ctrl |= METH_PHY_FDX;
195 		else
196 			priv->mac_ctrl &= ~METH_PHY_FDX;
197 		mace->eth.mac_ctrl = priv->mac_ctrl;
198 	}
199 
200 	if ((priv->mac_ctrl & METH_100MBIT) ^ speed) {
201 		DPRINTK("Setting %dMbs mode\n", speed ? 100 : 10);
202 		if (duplex)
203 			priv->mac_ctrl |= METH_100MBIT;
204 		else
205 			priv->mac_ctrl &= ~METH_100MBIT;
206 		mace->eth.mac_ctrl = priv->mac_ctrl;
207 	}
208 }
209 
210 
211 static int meth_init_tx_ring(struct meth_private *priv)
212 {
213 	/* Init TX ring */
214 	priv->tx_ring = dma_zalloc_coherent(NULL, TX_RING_BUFFER_SIZE,
215 					    &priv->tx_ring_dma, GFP_ATOMIC);
216 	if (!priv->tx_ring)
217 		return -ENOMEM;
218 
219 	priv->tx_count = priv->tx_read = priv->tx_write = 0;
220 	mace->eth.tx_ring_base = priv->tx_ring_dma;
221 	/* Now init skb save area */
222 	memset(priv->tx_skbs, 0, sizeof(priv->tx_skbs));
223 	memset(priv->tx_skb_dmas, 0, sizeof(priv->tx_skb_dmas));
224 	return 0;
225 }
226 
227 static int meth_init_rx_ring(struct meth_private *priv)
228 {
229 	int i;
230 
231 	for (i = 0; i < RX_RING_ENTRIES; i++) {
232 		priv->rx_skbs[i] = alloc_skb(METH_RX_BUFF_SIZE, 0);
233 		/* 8byte status vector + 3quad padding + 2byte padding,
234 		 * to put data on 64bit aligned boundary */
235 		skb_reserve(priv->rx_skbs[i],METH_RX_HEAD);
236 		priv->rx_ring[i]=(rx_packet*)(priv->rx_skbs[i]->head);
237 		/* I'll need to re-sync it after each RX */
238 		priv->rx_ring_dmas[i] =
239 			dma_map_single(NULL, priv->rx_ring[i],
240 				       METH_RX_BUFF_SIZE, DMA_FROM_DEVICE);
241 		mace->eth.rx_fifo = priv->rx_ring_dmas[i];
242 	}
243         priv->rx_write = 0;
244 	return 0;
245 }
246 static void meth_free_tx_ring(struct meth_private *priv)
247 {
248 	int i;
249 
250 	/* Remove any pending skb */
251 	for (i = 0; i < TX_RING_ENTRIES; i++) {
252 		if (priv->tx_skbs[i])
253 			dev_kfree_skb(priv->tx_skbs[i]);
254 		priv->tx_skbs[i] = NULL;
255 	}
256 	dma_free_coherent(NULL, TX_RING_BUFFER_SIZE, priv->tx_ring,
257 	                  priv->tx_ring_dma);
258 }
259 
260 /* Presumes RX DMA engine is stopped, and RX fifo ring is reset */
261 static void meth_free_rx_ring(struct meth_private *priv)
262 {
263 	int i;
264 
265 	for (i = 0; i < RX_RING_ENTRIES; i++) {
266 		dma_unmap_single(NULL, priv->rx_ring_dmas[i],
267 				 METH_RX_BUFF_SIZE, DMA_FROM_DEVICE);
268 		priv->rx_ring[i] = 0;
269 		priv->rx_ring_dmas[i] = 0;
270 		kfree_skb(priv->rx_skbs[i]);
271 	}
272 }
273 
274 int meth_reset(struct net_device *dev)
275 {
276 	struct meth_private *priv = netdev_priv(dev);
277 
278 	/* Reset card */
279 	mace->eth.mac_ctrl = SGI_MAC_RESET;
280 	udelay(1);
281 	mace->eth.mac_ctrl = 0;
282 	udelay(25);
283 
284 	/* Load ethernet address */
285 	load_eaddr(dev);
286 	/* Should load some "errata", but later */
287 
288 	/* Check for device */
289 	if (mdio_probe(priv) < 0) {
290 		DPRINTK("Unable to find PHY\n");
291 		return -ENODEV;
292 	}
293 
294 	/* Initial mode: 10 | Half-duplex | Accept normal packets */
295 	priv->mac_ctrl = METH_ACCEPT_MCAST | METH_DEFAULT_IPG;
296 	if (dev->flags & IFF_PROMISC)
297 		priv->mac_ctrl |= METH_PROMISC;
298 	mace->eth.mac_ctrl = priv->mac_ctrl;
299 
300 	/* Autonegotiate speed and duplex mode */
301 	meth_check_link(dev);
302 
303 	/* Now set dma control, but don't enable DMA, yet */
304 	priv->dma_ctrl = (4 << METH_RX_OFFSET_SHIFT) |
305 			 (RX_RING_ENTRIES << METH_RX_DEPTH_SHIFT);
306 	mace->eth.dma_ctrl = priv->dma_ctrl;
307 
308 	return 0;
309 }
310 
311 /*============End Helper Routines=====================*/
312 
313 /*
314  * Open and close
315  */
316 static int meth_open(struct net_device *dev)
317 {
318 	struct meth_private *priv = netdev_priv(dev);
319 	int ret;
320 
321 	priv->phy_addr = -1;    /* No PHY is known yet... */
322 
323 	/* Initialize the hardware */
324 	ret = meth_reset(dev);
325 	if (ret < 0)
326 		return ret;
327 
328 	/* Allocate the ring buffers */
329 	ret = meth_init_tx_ring(priv);
330 	if (ret < 0)
331 		return ret;
332 	ret = meth_init_rx_ring(priv);
333 	if (ret < 0)
334 		goto out_free_tx_ring;
335 
336 	ret = request_irq(dev->irq, meth_interrupt, 0, meth_str, dev);
337 	if (ret) {
338 		printk(KERN_ERR "%s: Can't get irq %d\n", dev->name, dev->irq);
339 		goto out_free_rx_ring;
340 	}
341 
342 	/* Start DMA */
343 	priv->dma_ctrl |= METH_DMA_TX_EN | /*METH_DMA_TX_INT_EN |*/
344 			  METH_DMA_RX_EN | METH_DMA_RX_INT_EN;
345 	mace->eth.dma_ctrl = priv->dma_ctrl;
346 
347 	DPRINTK("About to start queue\n");
348 	netif_start_queue(dev);
349 
350 	return 0;
351 
352 out_free_rx_ring:
353 	meth_free_rx_ring(priv);
354 out_free_tx_ring:
355 	meth_free_tx_ring(priv);
356 
357 	return ret;
358 }
359 
360 static int meth_release(struct net_device *dev)
361 {
362 	struct meth_private *priv = netdev_priv(dev);
363 
364 	DPRINTK("Stopping queue\n");
365 	netif_stop_queue(dev); /* can't transmit any more */
366 	/* shut down DMA */
367 	priv->dma_ctrl &= ~(METH_DMA_TX_EN | METH_DMA_TX_INT_EN |
368 			    METH_DMA_RX_EN | METH_DMA_RX_INT_EN);
369 	mace->eth.dma_ctrl = priv->dma_ctrl;
370 	free_irq(dev->irq, dev);
371 	meth_free_tx_ring(priv);
372 	meth_free_rx_ring(priv);
373 
374 	return 0;
375 }
376 
377 /*
378  * Receive a packet: retrieve, encapsulate and pass over to upper levels
379  */
380 static void meth_rx(struct net_device* dev, unsigned long int_status)
381 {
382 	struct sk_buff *skb;
383 	unsigned long status, flags;
384 	struct meth_private *priv = netdev_priv(dev);
385 	unsigned long fifo_rptr = (int_status & METH_INT_RX_RPTR_MASK) >> 8;
386 
387 	spin_lock_irqsave(&priv->meth_lock, flags);
388 	priv->dma_ctrl &= ~METH_DMA_RX_INT_EN;
389 	mace->eth.dma_ctrl = priv->dma_ctrl;
390 	spin_unlock_irqrestore(&priv->meth_lock, flags);
391 
392 	if (int_status & METH_INT_RX_UNDERFLOW) {
393 		fifo_rptr = (fifo_rptr - 1) & 0x0f;
394 	}
395 	while (priv->rx_write != fifo_rptr) {
396 		dma_unmap_single(NULL, priv->rx_ring_dmas[priv->rx_write],
397 				 METH_RX_BUFF_SIZE, DMA_FROM_DEVICE);
398 		status = priv->rx_ring[priv->rx_write]->status.raw;
399 #if MFE_DEBUG
400 		if (!(status & METH_RX_ST_VALID)) {
401 			DPRINTK("Not received? status=%016lx\n",status);
402 		}
403 #endif
404 		if ((!(status & METH_RX_STATUS_ERRORS)) && (status & METH_RX_ST_VALID)) {
405 			int len = (status & 0xffff) - 4; /* omit CRC */
406 			/* length sanity check */
407 			if (len < 60 || len > 1518) {
408 				printk(KERN_DEBUG "%s: bogus packet size: %ld, status=%#2Lx.\n",
409 				       dev->name, priv->rx_write,
410 				       priv->rx_ring[priv->rx_write]->status.raw);
411 				dev->stats.rx_errors++;
412 				dev->stats.rx_length_errors++;
413 				skb = priv->rx_skbs[priv->rx_write];
414 			} else {
415 				skb = alloc_skb(METH_RX_BUFF_SIZE, GFP_ATOMIC);
416 				if (!skb) {
417 					/* Ouch! No memory! Drop packet on the floor */
418 					DPRINTK("No mem: dropping packet\n");
419 					dev->stats.rx_dropped++;
420 					skb = priv->rx_skbs[priv->rx_write];
421 				} else {
422 					struct sk_buff *skb_c = priv->rx_skbs[priv->rx_write];
423 					/* 8byte status vector + 3quad padding + 2byte padding,
424 					 * to put data on 64bit aligned boundary */
425 					skb_reserve(skb, METH_RX_HEAD);
426 					/* Write metadata, and then pass to the receive level */
427 					skb_put(skb_c, len);
428 					priv->rx_skbs[priv->rx_write] = skb;
429 					skb_c->protocol = eth_type_trans(skb_c, dev);
430 					dev->stats.rx_packets++;
431 					dev->stats.rx_bytes += len;
432 					netif_rx(skb_c);
433 				}
434 			}
435 		} else {
436 			dev->stats.rx_errors++;
437 			skb=priv->rx_skbs[priv->rx_write];
438 #if MFE_DEBUG>0
439 			printk(KERN_WARNING "meth: RX error: status=0x%016lx\n",status);
440 			if(status&METH_RX_ST_RCV_CODE_VIOLATION)
441 				printk(KERN_WARNING "Receive Code Violation\n");
442 			if(status&METH_RX_ST_CRC_ERR)
443 				printk(KERN_WARNING "CRC error\n");
444 			if(status&METH_RX_ST_INV_PREAMBLE_CTX)
445 				printk(KERN_WARNING "Invalid Preamble Context\n");
446 			if(status&METH_RX_ST_LONG_EVT_SEEN)
447 				printk(KERN_WARNING "Long Event Seen...\n");
448 			if(status&METH_RX_ST_BAD_PACKET)
449 				printk(KERN_WARNING "Bad Packet\n");
450 			if(status&METH_RX_ST_CARRIER_EVT_SEEN)
451 				printk(KERN_WARNING "Carrier Event Seen\n");
452 #endif
453 		}
454 		priv->rx_ring[priv->rx_write] = (rx_packet*)skb->head;
455 		priv->rx_ring[priv->rx_write]->status.raw = 0;
456 		priv->rx_ring_dmas[priv->rx_write] =
457 			dma_map_single(NULL, priv->rx_ring[priv->rx_write],
458 				       METH_RX_BUFF_SIZE, DMA_FROM_DEVICE);
459 		mace->eth.rx_fifo = priv->rx_ring_dmas[priv->rx_write];
460 		ADVANCE_RX_PTR(priv->rx_write);
461 	}
462 	spin_lock_irqsave(&priv->meth_lock, flags);
463 	/* In case there was underflow, and Rx DMA was disabled */
464 	priv->dma_ctrl |= METH_DMA_RX_INT_EN | METH_DMA_RX_EN;
465 	mace->eth.dma_ctrl = priv->dma_ctrl;
466 	mace->eth.int_stat = METH_INT_RX_THRESHOLD;
467 	spin_unlock_irqrestore(&priv->meth_lock, flags);
468 }
469 
470 static int meth_tx_full(struct net_device *dev)
471 {
472 	struct meth_private *priv = netdev_priv(dev);
473 
474 	return priv->tx_count >= TX_RING_ENTRIES - 1;
475 }
476 
477 static void meth_tx_cleanup(struct net_device* dev, unsigned long int_status)
478 {
479 	struct meth_private *priv = netdev_priv(dev);
480 	unsigned long status, flags;
481 	struct sk_buff *skb;
482 	unsigned long rptr = (int_status&TX_INFO_RPTR) >> 16;
483 
484 	spin_lock_irqsave(&priv->meth_lock, flags);
485 
486 	/* Stop DMA notification */
487 	priv->dma_ctrl &= ~(METH_DMA_TX_INT_EN);
488 	mace->eth.dma_ctrl = priv->dma_ctrl;
489 
490 	while (priv->tx_read != rptr) {
491 		skb = priv->tx_skbs[priv->tx_read];
492 		status = priv->tx_ring[priv->tx_read].header.raw;
493 #if MFE_DEBUG>=1
494 		if (priv->tx_read == priv->tx_write)
495 			DPRINTK("Auchi! tx_read=%d,tx_write=%d,rptr=%d?\n", priv->tx_read, priv->tx_write,rptr);
496 #endif
497 		if (status & METH_TX_ST_DONE) {
498 			if (status & METH_TX_ST_SUCCESS){
499 				dev->stats.tx_packets++;
500 				dev->stats.tx_bytes += skb->len;
501 			} else {
502 				dev->stats.tx_errors++;
503 #if MFE_DEBUG>=1
504 				DPRINTK("TX error: status=%016lx <",status);
505 				if(status & METH_TX_ST_SUCCESS)
506 					printk(" SUCCESS");
507 				if(status & METH_TX_ST_TOOLONG)
508 					printk(" TOOLONG");
509 				if(status & METH_TX_ST_UNDERRUN)
510 					printk(" UNDERRUN");
511 				if(status & METH_TX_ST_EXCCOLL)
512 					printk(" EXCCOLL");
513 				if(status & METH_TX_ST_DEFER)
514 					printk(" DEFER");
515 				if(status & METH_TX_ST_LATECOLL)
516 					printk(" LATECOLL");
517 				printk(" >\n");
518 #endif
519 			}
520 		} else {
521 			DPRINTK("RPTR points us here, but packet not done?\n");
522 			break;
523 		}
524 		dev_kfree_skb_irq(skb);
525 		priv->tx_skbs[priv->tx_read] = NULL;
526 		priv->tx_ring[priv->tx_read].header.raw = 0;
527 		priv->tx_read = (priv->tx_read+1)&(TX_RING_ENTRIES-1);
528 		priv->tx_count--;
529 	}
530 
531 	/* wake up queue if it was stopped */
532 	if (netif_queue_stopped(dev) && !meth_tx_full(dev)) {
533 		netif_wake_queue(dev);
534 	}
535 
536 	mace->eth.int_stat = METH_INT_TX_EMPTY | METH_INT_TX_PKT;
537 	spin_unlock_irqrestore(&priv->meth_lock, flags);
538 }
539 
540 static void meth_error(struct net_device* dev, unsigned status)
541 {
542 	struct meth_private *priv = netdev_priv(dev);
543 	unsigned long flags;
544 
545 	printk(KERN_WARNING "meth: error status: 0x%08x\n",status);
546 	/* check for errors too... */
547 	if (status & (METH_INT_TX_LINK_FAIL))
548 		printk(KERN_WARNING "meth: link failure\n");
549 	/* Should I do full reset in this case? */
550 	if (status & (METH_INT_MEM_ERROR))
551 		printk(KERN_WARNING "meth: memory error\n");
552 	if (status & (METH_INT_TX_ABORT))
553 		printk(KERN_WARNING "meth: aborted\n");
554 	if (status & (METH_INT_RX_OVERFLOW))
555 		printk(KERN_WARNING "meth: Rx overflow\n");
556 	if (status & (METH_INT_RX_UNDERFLOW)) {
557 		printk(KERN_WARNING "meth: Rx underflow\n");
558 		spin_lock_irqsave(&priv->meth_lock, flags);
559 		mace->eth.int_stat = METH_INT_RX_UNDERFLOW;
560 		/* more underflow interrupts will be delivered,
561 		 * effectively throwing us into an infinite loop.
562 		 *  Thus I stop processing Rx in this case. */
563 		priv->dma_ctrl &= ~METH_DMA_RX_EN;
564 		mace->eth.dma_ctrl = priv->dma_ctrl;
565 		DPRINTK("Disabled meth Rx DMA temporarily\n");
566 		spin_unlock_irqrestore(&priv->meth_lock, flags);
567 	}
568 	mace->eth.int_stat = METH_INT_ERROR;
569 }
570 
571 /*
572  * The typical interrupt entry point
573  */
574 static irqreturn_t meth_interrupt(int irq, void *dev_id)
575 {
576 	struct net_device *dev = (struct net_device *)dev_id;
577 	struct meth_private *priv = netdev_priv(dev);
578 	unsigned long status;
579 
580 	status = mace->eth.int_stat;
581 	while (status & 0xff) {
582 		/* First handle errors - if we get Rx underflow,
583 		 * Rx DMA will be disabled, and Rx handler will reenable
584 		 * it. I don't think it's possible to get Rx underflow,
585 		 * without getting Rx interrupt */
586 		if (status & METH_INT_ERROR) {
587 			meth_error(dev, status);
588 		}
589 		if (status & (METH_INT_TX_EMPTY | METH_INT_TX_PKT)) {
590 			/* a transmission is over: free the skb */
591 			meth_tx_cleanup(dev, status);
592 		}
593 		if (status & METH_INT_RX_THRESHOLD) {
594 			if (!(priv->dma_ctrl & METH_DMA_RX_INT_EN))
595 				break;
596 			/* send it to meth_rx for handling */
597 			meth_rx(dev, status);
598 		}
599 		status = mace->eth.int_stat;
600 	}
601 
602 	return IRQ_HANDLED;
603 }
604 
605 /*
606  * Transmits packets that fit into TX descriptor (are <=120B)
607  */
608 static void meth_tx_short_prepare(struct meth_private *priv,
609 				  struct sk_buff *skb)
610 {
611 	tx_packet *desc = &priv->tx_ring[priv->tx_write];
612 	int len = (skb->len < ETH_ZLEN) ? ETH_ZLEN : skb->len;
613 
614 	desc->header.raw = METH_TX_CMD_INT_EN | (len-1) | ((128-len) << 16);
615 	/* maybe I should set whole thing to 0 first... */
616 	skb_copy_from_linear_data(skb, desc->data.dt + (120 - len), skb->len);
617 	if (skb->len < len)
618 		memset(desc->data.dt + 120 - len + skb->len, 0, len-skb->len);
619 }
620 #define TX_CATBUF1 BIT(25)
621 static void meth_tx_1page_prepare(struct meth_private *priv,
622 				  struct sk_buff *skb)
623 {
624 	tx_packet *desc = &priv->tx_ring[priv->tx_write];
625 	void *buffer_data = (void *)(((unsigned long)skb->data + 7) & ~7);
626 	int unaligned_len = (int)((unsigned long)buffer_data - (unsigned long)skb->data);
627 	int buffer_len = skb->len - unaligned_len;
628 	dma_addr_t catbuf;
629 
630 	desc->header.raw = METH_TX_CMD_INT_EN | TX_CATBUF1 | (skb->len - 1);
631 
632 	/* unaligned part */
633 	if (unaligned_len) {
634 		skb_copy_from_linear_data(skb, desc->data.dt + (120 - unaligned_len),
635 			      unaligned_len);
636 		desc->header.raw |= (128 - unaligned_len) << 16;
637 	}
638 
639 	/* first page */
640 	catbuf = dma_map_single(NULL, buffer_data, buffer_len,
641 				DMA_TO_DEVICE);
642 	desc->data.cat_buf[0].form.start_addr = catbuf >> 3;
643 	desc->data.cat_buf[0].form.len = buffer_len - 1;
644 }
645 #define TX_CATBUF2 BIT(26)
646 static void meth_tx_2page_prepare(struct meth_private *priv,
647 				  struct sk_buff *skb)
648 {
649 	tx_packet *desc = &priv->tx_ring[priv->tx_write];
650 	void *buffer1_data = (void *)(((unsigned long)skb->data + 7) & ~7);
651 	void *buffer2_data = (void *)PAGE_ALIGN((unsigned long)skb->data);
652 	int unaligned_len = (int)((unsigned long)buffer1_data - (unsigned long)skb->data);
653 	int buffer1_len = (int)((unsigned long)buffer2_data - (unsigned long)buffer1_data);
654 	int buffer2_len = skb->len - buffer1_len - unaligned_len;
655 	dma_addr_t catbuf1, catbuf2;
656 
657 	desc->header.raw = METH_TX_CMD_INT_EN | TX_CATBUF1 | TX_CATBUF2| (skb->len - 1);
658 	/* unaligned part */
659 	if (unaligned_len){
660 		skb_copy_from_linear_data(skb, desc->data.dt + (120 - unaligned_len),
661 			      unaligned_len);
662 		desc->header.raw |= (128 - unaligned_len) << 16;
663 	}
664 
665 	/* first page */
666 	catbuf1 = dma_map_single(NULL, buffer1_data, buffer1_len,
667 				 DMA_TO_DEVICE);
668 	desc->data.cat_buf[0].form.start_addr = catbuf1 >> 3;
669 	desc->data.cat_buf[0].form.len = buffer1_len - 1;
670 	/* second page */
671 	catbuf2 = dma_map_single(NULL, buffer2_data, buffer2_len,
672 				 DMA_TO_DEVICE);
673 	desc->data.cat_buf[1].form.start_addr = catbuf2 >> 3;
674 	desc->data.cat_buf[1].form.len = buffer2_len - 1;
675 }
676 
677 static void meth_add_to_tx_ring(struct meth_private *priv, struct sk_buff *skb)
678 {
679 	/* Remember the skb, so we can free it at interrupt time */
680 	priv->tx_skbs[priv->tx_write] = skb;
681 	if (skb->len <= 120) {
682 		/* Whole packet fits into descriptor */
683 		meth_tx_short_prepare(priv, skb);
684 	} else if (PAGE_ALIGN((unsigned long)skb->data) !=
685 		   PAGE_ALIGN((unsigned long)skb->data + skb->len - 1)) {
686 		/* Packet crosses page boundary */
687 		meth_tx_2page_prepare(priv, skb);
688 	} else {
689 		/* Packet is in one page */
690 		meth_tx_1page_prepare(priv, skb);
691 	}
692 	priv->tx_write = (priv->tx_write + 1) & (TX_RING_ENTRIES - 1);
693 	mace->eth.tx_info = priv->tx_write;
694 	priv->tx_count++;
695 }
696 
697 /*
698  * Transmit a packet (called by the kernel)
699  */
700 static int meth_tx(struct sk_buff *skb, struct net_device *dev)
701 {
702 	struct meth_private *priv = netdev_priv(dev);
703 	unsigned long flags;
704 
705 	spin_lock_irqsave(&priv->meth_lock, flags);
706 	/* Stop DMA notification */
707 	priv->dma_ctrl &= ~(METH_DMA_TX_INT_EN);
708 	mace->eth.dma_ctrl = priv->dma_ctrl;
709 
710 	meth_add_to_tx_ring(priv, skb);
711 	dev->trans_start = jiffies; /* save the timestamp */
712 
713 	/* If TX ring is full, tell the upper layer to stop sending packets */
714 	if (meth_tx_full(dev)) {
715 	        printk(KERN_DEBUG "TX full: stopping\n");
716 		netif_stop_queue(dev);
717 	}
718 
719 	/* Restart DMA notification */
720 	priv->dma_ctrl |= METH_DMA_TX_INT_EN;
721 	mace->eth.dma_ctrl = priv->dma_ctrl;
722 
723 	spin_unlock_irqrestore(&priv->meth_lock, flags);
724 
725 	return NETDEV_TX_OK;
726 }
727 
728 /*
729  * Deal with a transmit timeout.
730  */
731 static void meth_tx_timeout(struct net_device *dev)
732 {
733 	struct meth_private *priv = netdev_priv(dev);
734 	unsigned long flags;
735 
736 	printk(KERN_WARNING "%s: transmit timed out\n", dev->name);
737 
738 	/* Protect against concurrent rx interrupts */
739 	spin_lock_irqsave(&priv->meth_lock,flags);
740 
741 	/* Try to reset the interface. */
742 	meth_reset(dev);
743 
744 	dev->stats.tx_errors++;
745 
746 	/* Clear all rings */
747 	meth_free_tx_ring(priv);
748 	meth_free_rx_ring(priv);
749 	meth_init_tx_ring(priv);
750 	meth_init_rx_ring(priv);
751 
752 	/* Restart dma */
753 	priv->dma_ctrl |= METH_DMA_TX_EN | METH_DMA_RX_EN | METH_DMA_RX_INT_EN;
754 	mace->eth.dma_ctrl = priv->dma_ctrl;
755 
756 	/* Enable interrupt */
757 	spin_unlock_irqrestore(&priv->meth_lock, flags);
758 
759 	dev->trans_start = jiffies; /* prevent tx timeout */
760 	netif_wake_queue(dev);
761 }
762 
763 /*
764  * Ioctl commands
765  */
766 static int meth_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
767 {
768 	/* XXX Not yet implemented */
769 	switch(cmd) {
770 	case SIOCGMIIPHY:
771 	case SIOCGMIIREG:
772 	case SIOCSMIIREG:
773 	default:
774 		return -EOPNOTSUPP;
775 	}
776 }
777 
778 static void meth_set_rx_mode(struct net_device *dev)
779 {
780 	struct meth_private *priv = netdev_priv(dev);
781 	unsigned long flags;
782 
783 	netif_stop_queue(dev);
784 	spin_lock_irqsave(&priv->meth_lock, flags);
785 	priv->mac_ctrl &= ~METH_PROMISC;
786 
787 	if (dev->flags & IFF_PROMISC) {
788 		priv->mac_ctrl |= METH_PROMISC;
789 		priv->mcast_filter = 0xffffffffffffffffUL;
790 	} else if ((netdev_mc_count(dev) > METH_MCF_LIMIT) ||
791 		   (dev->flags & IFF_ALLMULTI)) {
792 		priv->mac_ctrl |= METH_ACCEPT_AMCAST;
793 		priv->mcast_filter = 0xffffffffffffffffUL;
794 	} else {
795 		struct netdev_hw_addr *ha;
796 		priv->mac_ctrl |= METH_ACCEPT_MCAST;
797 
798 		netdev_for_each_mc_addr(ha, dev)
799 			set_bit((ether_crc(ETH_ALEN, ha->addr) >> 26),
800 			        (volatile unsigned long *)&priv->mcast_filter);
801 	}
802 
803 	/* Write the changes to the chip registers. */
804 	mace->eth.mac_ctrl = priv->mac_ctrl;
805 	mace->eth.mcast_filter = priv->mcast_filter;
806 
807 	/* Done! */
808 	spin_unlock_irqrestore(&priv->meth_lock, flags);
809 	netif_wake_queue(dev);
810 }
811 
812 static const struct net_device_ops meth_netdev_ops = {
813 	.ndo_open		= meth_open,
814 	.ndo_stop		= meth_release,
815 	.ndo_start_xmit		= meth_tx,
816 	.ndo_do_ioctl		= meth_ioctl,
817 	.ndo_tx_timeout		= meth_tx_timeout,
818 	.ndo_change_mtu		= eth_change_mtu,
819 	.ndo_validate_addr	= eth_validate_addr,
820 	.ndo_set_mac_address	= eth_mac_addr,
821 	.ndo_set_rx_mode    	= meth_set_rx_mode,
822 };
823 
824 /*
825  * The init function.
826  */
827 static int meth_probe(struct platform_device *pdev)
828 {
829 	struct net_device *dev;
830 	struct meth_private *priv;
831 	int err;
832 
833 	dev = alloc_etherdev(sizeof(struct meth_private));
834 	if (!dev)
835 		return -ENOMEM;
836 
837 	dev->netdev_ops		= &meth_netdev_ops;
838 	dev->watchdog_timeo	= timeout;
839 	dev->irq		= MACE_ETHERNET_IRQ;
840 	dev->base_addr		= (unsigned long)&mace->eth;
841 	memcpy(dev->dev_addr, o2meth_eaddr, ETH_ALEN);
842 
843 	priv = netdev_priv(dev);
844 	spin_lock_init(&priv->meth_lock);
845 	SET_NETDEV_DEV(dev, &pdev->dev);
846 
847 	err = register_netdev(dev);
848 	if (err) {
849 		free_netdev(dev);
850 		return err;
851 	}
852 
853 	printk(KERN_INFO "%s: SGI MACE Ethernet rev. %d\n",
854 	       dev->name, (unsigned int)(mace->eth.mac_ctrl >> 29));
855 	return 0;
856 }
857 
858 static int __exit meth_remove(struct platform_device *pdev)
859 {
860 	struct net_device *dev = platform_get_drvdata(pdev);
861 
862 	unregister_netdev(dev);
863 	free_netdev(dev);
864 
865 	return 0;
866 }
867 
868 static struct platform_driver meth_driver = {
869 	.probe	= meth_probe,
870 	.remove	= __exit_p(meth_remove),
871 	.driver = {
872 		.name	= "meth",
873 	}
874 };
875 
876 module_platform_driver(meth_driver);
877 
878 MODULE_AUTHOR("Ilya Volynets <ilya@theIlya.com>");
879 MODULE_DESCRIPTION("SGI O2 Builtin Fast Ethernet driver");
880 MODULE_LICENSE("GPL");
881 MODULE_ALIAS("platform:meth");
882