xref: /openbmc/linux/drivers/net/ethernet/sgi/meth.c (revision f7777dcc)
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/init.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/platform_device.h>
17 #include <linux/slab.h>
18 #include <linux/errno.h>
19 #include <linux/types.h>
20 #include <linux/interrupt.h>
21 
22 #include <linux/in.h>
23 #include <linux/in6.h>
24 #include <linux/device.h> /* struct device, et al */
25 #include <linux/netdevice.h>   /* struct device, and other headers */
26 #include <linux/etherdevice.h> /* eth_type_trans */
27 #include <linux/ip.h>          /* struct iphdr */
28 #include <linux/tcp.h>         /* struct tcphdr */
29 #include <linux/skbuff.h>
30 #include <linux/mii.h>         /* MII definitions */
31 #include <linux/crc32.h>
32 
33 #include <asm/ip32/mace.h>
34 #include <asm/ip32/ip32_ints.h>
35 
36 #include <asm/io.h>
37 
38 #include "meth.h"
39 
40 #ifndef MFE_DEBUG
41 #define MFE_DEBUG 0
42 #endif
43 
44 #if MFE_DEBUG>=1
45 #define DPRINTK(str,args...) printk(KERN_DEBUG "meth: %s: " str, __func__ , ## args)
46 #define MFE_RX_DEBUG 2
47 #else
48 #define DPRINTK(str,args...)
49 #define MFE_RX_DEBUG 0
50 #endif
51 
52 
53 static const char *meth_str="SGI O2 Fast Ethernet";
54 
55 /* The maximum time waited (in jiffies) before assuming a Tx failed. (400ms) */
56 #define TX_TIMEOUT (400*HZ/1000)
57 
58 static int timeout = TX_TIMEOUT;
59 module_param(timeout, int, 0);
60 
61 /*
62  * Maximum number of multicast addresses to filter (vs. Rx-all-multicast).
63  * MACE Ethernet uses a 64 element hash table based on the Ethernet CRC.
64  */
65 #define METH_MCF_LIMIT 32
66 
67 /*
68  * This structure is private to each device. It is used to pass
69  * packets in and out, so there is place for a packet
70  */
71 struct meth_private {
72 	/* in-memory copy of MAC Control register */
73 	u64 mac_ctrl;
74 
75 	/* in-memory copy of DMA Control register */
76 	unsigned long dma_ctrl;
77 	/* address of PHY, used by mdio_* functions, initialized in mdio_probe */
78 	unsigned long phy_addr;
79 	tx_packet *tx_ring;
80 	dma_addr_t tx_ring_dma;
81 	struct sk_buff *tx_skbs[TX_RING_ENTRIES];
82 	dma_addr_t tx_skb_dmas[TX_RING_ENTRIES];
83 	unsigned long tx_read, tx_write, tx_count;
84 
85 	rx_packet *rx_ring[RX_RING_ENTRIES];
86 	dma_addr_t rx_ring_dmas[RX_RING_ENTRIES];
87 	struct sk_buff *rx_skbs[RX_RING_ENTRIES];
88 	unsigned long rx_write;
89 
90 	/* Multicast filter. */
91 	u64 mcast_filter;
92 
93 	spinlock_t meth_lock;
94 };
95 
96 static void meth_tx_timeout(struct net_device *dev);
97 static irqreturn_t meth_interrupt(int irq, void *dev_id);
98 
99 /* global, initialized in ip32-setup.c */
100 char o2meth_eaddr[8]={0,0,0,0,0,0,0,0};
101 
102 static inline void load_eaddr(struct net_device *dev)
103 {
104 	int i;
105 	u64 macaddr;
106 
107 	DPRINTK("Loading MAC Address: %pM\n", dev->dev_addr);
108 	macaddr = 0;
109 	for (i = 0; i < 6; i++)
110 		macaddr |= (u64)dev->dev_addr[i] << ((5 - i) * 8);
111 
112 	mace->eth.mac_addr = macaddr;
113 }
114 
115 /*
116  * Waits for BUSY status of mdio bus to clear
117  */
118 #define WAIT_FOR_PHY(___rval)					\
119 	while ((___rval = mace->eth.phy_data) & MDIO_BUSY) {	\
120 		udelay(25);					\
121 	}
122 /*read phy register, return value read */
123 static unsigned long mdio_read(struct meth_private *priv, unsigned long phyreg)
124 {
125 	unsigned long rval;
126 	WAIT_FOR_PHY(rval);
127 	mace->eth.phy_regs = (priv->phy_addr << 5) | (phyreg & 0x1f);
128 	udelay(25);
129 	mace->eth.phy_trans_go = 1;
130 	udelay(25);
131 	WAIT_FOR_PHY(rval);
132 	return rval & MDIO_DATA_MASK;
133 }
134 
135 static int mdio_probe(struct meth_private *priv)
136 {
137 	int i;
138 	unsigned long p2, p3, flags;
139 	/* check if phy is detected already */
140 	if(priv->phy_addr>=0&&priv->phy_addr<32)
141 		return 0;
142 	spin_lock_irqsave(&priv->meth_lock, flags);
143 	for (i=0;i<32;++i){
144 		priv->phy_addr=i;
145 		p2=mdio_read(priv,2);
146 		p3=mdio_read(priv,3);
147 #if MFE_DEBUG>=2
148 		switch ((p2<<12)|(p3>>4)){
149 		case PHY_QS6612X:
150 			DPRINTK("PHY is QS6612X\n");
151 			break;
152 		case PHY_ICS1889:
153 			DPRINTK("PHY is ICS1889\n");
154 			break;
155 		case PHY_ICS1890:
156 			DPRINTK("PHY is ICS1890\n");
157 			break;
158 		case PHY_DP83840:
159 			DPRINTK("PHY is DP83840\n");
160 			break;
161 		}
162 #endif
163 		if(p2!=0xffff&&p2!=0x0000){
164 			DPRINTK("PHY code: %x\n",(p2<<12)|(p3>>4));
165 			break;
166 		}
167 	}
168 	spin_unlock_irqrestore(&priv->meth_lock, flags);
169 	if(priv->phy_addr<32) {
170 		return 0;
171 	}
172 	DPRINTK("Oopsie! PHY is not known!\n");
173 	priv->phy_addr=-1;
174 	return -ENODEV;
175 }
176 
177 static void meth_check_link(struct net_device *dev)
178 {
179 	struct meth_private *priv = netdev_priv(dev);
180 	unsigned long mii_advertising = mdio_read(priv, 4);
181 	unsigned long mii_partner = mdio_read(priv, 5);
182 	unsigned long negotiated = mii_advertising & mii_partner;
183 	unsigned long duplex, speed;
184 
185 	if (mii_partner == 0xffff)
186 		return;
187 
188 	speed = (negotiated & 0x0380) ? METH_100MBIT : 0;
189 	duplex = ((negotiated & 0x0100) || (negotiated & 0x01C0) == 0x0040) ?
190 		 METH_PHY_FDX : 0;
191 
192 	if ((priv->mac_ctrl & METH_PHY_FDX) ^ duplex) {
193 		DPRINTK("Setting %s-duplex\n", duplex ? "full" : "half");
194 		if (duplex)
195 			priv->mac_ctrl |= METH_PHY_FDX;
196 		else
197 			priv->mac_ctrl &= ~METH_PHY_FDX;
198 		mace->eth.mac_ctrl = priv->mac_ctrl;
199 	}
200 
201 	if ((priv->mac_ctrl & METH_100MBIT) ^ speed) {
202 		DPRINTK("Setting %dMbs mode\n", speed ? 100 : 10);
203 		if (duplex)
204 			priv->mac_ctrl |= METH_100MBIT;
205 		else
206 			priv->mac_ctrl &= ~METH_100MBIT;
207 		mace->eth.mac_ctrl = priv->mac_ctrl;
208 	}
209 }
210 
211 
212 static int meth_init_tx_ring(struct meth_private *priv)
213 {
214 	/* Init TX ring */
215 	priv->tx_ring = dma_zalloc_coherent(NULL, TX_RING_BUFFER_SIZE,
216 					    &priv->tx_ring_dma, GFP_ATOMIC);
217 	if (!priv->tx_ring)
218 		return -ENOMEM;
219 
220 	priv->tx_count = priv->tx_read = priv->tx_write = 0;
221 	mace->eth.tx_ring_base = priv->tx_ring_dma;
222 	/* Now init skb save area */
223 	memset(priv->tx_skbs, 0, sizeof(priv->tx_skbs));
224 	memset(priv->tx_skb_dmas, 0, sizeof(priv->tx_skb_dmas));
225 	return 0;
226 }
227 
228 static int meth_init_rx_ring(struct meth_private *priv)
229 {
230 	int i;
231 
232 	for (i = 0; i < RX_RING_ENTRIES; i++) {
233 		priv->rx_skbs[i] = alloc_skb(METH_RX_BUFF_SIZE, 0);
234 		/* 8byte status vector + 3quad padding + 2byte padding,
235 		 * to put data on 64bit aligned boundary */
236 		skb_reserve(priv->rx_skbs[i],METH_RX_HEAD);
237 		priv->rx_ring[i]=(rx_packet*)(priv->rx_skbs[i]->head);
238 		/* I'll need to re-sync it after each RX */
239 		priv->rx_ring_dmas[i] =
240 			dma_map_single(NULL, priv->rx_ring[i],
241 				       METH_RX_BUFF_SIZE, DMA_FROM_DEVICE);
242 		mace->eth.rx_fifo = priv->rx_ring_dmas[i];
243 	}
244         priv->rx_write = 0;
245 	return 0;
246 }
247 static void meth_free_tx_ring(struct meth_private *priv)
248 {
249 	int i;
250 
251 	/* Remove any pending skb */
252 	for (i = 0; i < TX_RING_ENTRIES; i++) {
253 		if (priv->tx_skbs[i])
254 			dev_kfree_skb(priv->tx_skbs[i]);
255 		priv->tx_skbs[i] = NULL;
256 	}
257 	dma_free_coherent(NULL, TX_RING_BUFFER_SIZE, priv->tx_ring,
258 	                  priv->tx_ring_dma);
259 }
260 
261 /* Presumes RX DMA engine is stopped, and RX fifo ring is reset */
262 static void meth_free_rx_ring(struct meth_private *priv)
263 {
264 	int i;
265 
266 	for (i = 0; i < RX_RING_ENTRIES; i++) {
267 		dma_unmap_single(NULL, priv->rx_ring_dmas[i],
268 				 METH_RX_BUFF_SIZE, DMA_FROM_DEVICE);
269 		priv->rx_ring[i] = 0;
270 		priv->rx_ring_dmas[i] = 0;
271 		kfree_skb(priv->rx_skbs[i]);
272 	}
273 }
274 
275 int meth_reset(struct net_device *dev)
276 {
277 	struct meth_private *priv = netdev_priv(dev);
278 
279 	/* Reset card */
280 	mace->eth.mac_ctrl = SGI_MAC_RESET;
281 	udelay(1);
282 	mace->eth.mac_ctrl = 0;
283 	udelay(25);
284 
285 	/* Load ethernet address */
286 	load_eaddr(dev);
287 	/* Should load some "errata", but later */
288 
289 	/* Check for device */
290 	if (mdio_probe(priv) < 0) {
291 		DPRINTK("Unable to find PHY\n");
292 		return -ENODEV;
293 	}
294 
295 	/* Initial mode: 10 | Half-duplex | Accept normal packets */
296 	priv->mac_ctrl = METH_ACCEPT_MCAST | METH_DEFAULT_IPG;
297 	if (dev->flags & IFF_PROMISC)
298 		priv->mac_ctrl |= METH_PROMISC;
299 	mace->eth.mac_ctrl = priv->mac_ctrl;
300 
301 	/* Autonegotiate speed and duplex mode */
302 	meth_check_link(dev);
303 
304 	/* Now set dma control, but don't enable DMA, yet */
305 	priv->dma_ctrl = (4 << METH_RX_OFFSET_SHIFT) |
306 			 (RX_RING_ENTRIES << METH_RX_DEPTH_SHIFT);
307 	mace->eth.dma_ctrl = priv->dma_ctrl;
308 
309 	return 0;
310 }
311 
312 /*============End Helper Routines=====================*/
313 
314 /*
315  * Open and close
316  */
317 static int meth_open(struct net_device *dev)
318 {
319 	struct meth_private *priv = netdev_priv(dev);
320 	int ret;
321 
322 	priv->phy_addr = -1;    /* No PHY is known yet... */
323 
324 	/* Initialize the hardware */
325 	ret = meth_reset(dev);
326 	if (ret < 0)
327 		return ret;
328 
329 	/* Allocate the ring buffers */
330 	ret = meth_init_tx_ring(priv);
331 	if (ret < 0)
332 		return ret;
333 	ret = meth_init_rx_ring(priv);
334 	if (ret < 0)
335 		goto out_free_tx_ring;
336 
337 	ret = request_irq(dev->irq, meth_interrupt, 0, meth_str, dev);
338 	if (ret) {
339 		printk(KERN_ERR "%s: Can't get irq %d\n", dev->name, dev->irq);
340 		goto out_free_rx_ring;
341 	}
342 
343 	/* Start DMA */
344 	priv->dma_ctrl |= METH_DMA_TX_EN | /*METH_DMA_TX_INT_EN |*/
345 			  METH_DMA_RX_EN | METH_DMA_RX_INT_EN;
346 	mace->eth.dma_ctrl = priv->dma_ctrl;
347 
348 	DPRINTK("About to start queue\n");
349 	netif_start_queue(dev);
350 
351 	return 0;
352 
353 out_free_rx_ring:
354 	meth_free_rx_ring(priv);
355 out_free_tx_ring:
356 	meth_free_tx_ring(priv);
357 
358 	return ret;
359 }
360 
361 static int meth_release(struct net_device *dev)
362 {
363 	struct meth_private *priv = netdev_priv(dev);
364 
365 	DPRINTK("Stopping queue\n");
366 	netif_stop_queue(dev); /* can't transmit any more */
367 	/* shut down DMA */
368 	priv->dma_ctrl &= ~(METH_DMA_TX_EN | METH_DMA_TX_INT_EN |
369 			    METH_DMA_RX_EN | METH_DMA_RX_INT_EN);
370 	mace->eth.dma_ctrl = priv->dma_ctrl;
371 	free_irq(dev->irq, dev);
372 	meth_free_tx_ring(priv);
373 	meth_free_rx_ring(priv);
374 
375 	return 0;
376 }
377 
378 /*
379  * Receive a packet: retrieve, encapsulate and pass over to upper levels
380  */
381 static void meth_rx(struct net_device* dev, unsigned long int_status)
382 {
383 	struct sk_buff *skb;
384 	unsigned long status, flags;
385 	struct meth_private *priv = netdev_priv(dev);
386 	unsigned long fifo_rptr = (int_status & METH_INT_RX_RPTR_MASK) >> 8;
387 
388 	spin_lock_irqsave(&priv->meth_lock, flags);
389 	priv->dma_ctrl &= ~METH_DMA_RX_INT_EN;
390 	mace->eth.dma_ctrl = priv->dma_ctrl;
391 	spin_unlock_irqrestore(&priv->meth_lock, flags);
392 
393 	if (int_status & METH_INT_RX_UNDERFLOW) {
394 		fifo_rptr = (fifo_rptr - 1) & 0x0f;
395 	}
396 	while (priv->rx_write != fifo_rptr) {
397 		dma_unmap_single(NULL, priv->rx_ring_dmas[priv->rx_write],
398 				 METH_RX_BUFF_SIZE, DMA_FROM_DEVICE);
399 		status = priv->rx_ring[priv->rx_write]->status.raw;
400 #if MFE_DEBUG
401 		if (!(status & METH_RX_ST_VALID)) {
402 			DPRINTK("Not received? status=%016lx\n",status);
403 		}
404 #endif
405 		if ((!(status & METH_RX_STATUS_ERRORS)) && (status & METH_RX_ST_VALID)) {
406 			int len = (status & 0xffff) - 4; /* omit CRC */
407 			/* length sanity check */
408 			if (len < 60 || len > 1518) {
409 				printk(KERN_DEBUG "%s: bogus packet size: %ld, status=%#2Lx.\n",
410 				       dev->name, priv->rx_write,
411 				       priv->rx_ring[priv->rx_write]->status.raw);
412 				dev->stats.rx_errors++;
413 				dev->stats.rx_length_errors++;
414 				skb = priv->rx_skbs[priv->rx_write];
415 			} else {
416 				skb = alloc_skb(METH_RX_BUFF_SIZE, GFP_ATOMIC);
417 				if (!skb) {
418 					/* Ouch! No memory! Drop packet on the floor */
419 					DPRINTK("No mem: dropping packet\n");
420 					dev->stats.rx_dropped++;
421 					skb = priv->rx_skbs[priv->rx_write];
422 				} else {
423 					struct sk_buff *skb_c = priv->rx_skbs[priv->rx_write];
424 					/* 8byte status vector + 3quad padding + 2byte padding,
425 					 * to put data on 64bit aligned boundary */
426 					skb_reserve(skb, METH_RX_HEAD);
427 					/* Write metadata, and then pass to the receive level */
428 					skb_put(skb_c, len);
429 					priv->rx_skbs[priv->rx_write] = skb;
430 					skb_c->protocol = eth_type_trans(skb_c, dev);
431 					dev->stats.rx_packets++;
432 					dev->stats.rx_bytes += len;
433 					netif_rx(skb_c);
434 				}
435 			}
436 		} else {
437 			dev->stats.rx_errors++;
438 			skb=priv->rx_skbs[priv->rx_write];
439 #if MFE_DEBUG>0
440 			printk(KERN_WARNING "meth: RX error: status=0x%016lx\n",status);
441 			if(status&METH_RX_ST_RCV_CODE_VIOLATION)
442 				printk(KERN_WARNING "Receive Code Violation\n");
443 			if(status&METH_RX_ST_CRC_ERR)
444 				printk(KERN_WARNING "CRC error\n");
445 			if(status&METH_RX_ST_INV_PREAMBLE_CTX)
446 				printk(KERN_WARNING "Invalid Preamble Context\n");
447 			if(status&METH_RX_ST_LONG_EVT_SEEN)
448 				printk(KERN_WARNING "Long Event Seen...\n");
449 			if(status&METH_RX_ST_BAD_PACKET)
450 				printk(KERN_WARNING "Bad Packet\n");
451 			if(status&METH_RX_ST_CARRIER_EVT_SEEN)
452 				printk(KERN_WARNING "Carrier Event Seen\n");
453 #endif
454 		}
455 		priv->rx_ring[priv->rx_write] = (rx_packet*)skb->head;
456 		priv->rx_ring[priv->rx_write]->status.raw = 0;
457 		priv->rx_ring_dmas[priv->rx_write] =
458 			dma_map_single(NULL, priv->rx_ring[priv->rx_write],
459 				       METH_RX_BUFF_SIZE, DMA_FROM_DEVICE);
460 		mace->eth.rx_fifo = priv->rx_ring_dmas[priv->rx_write];
461 		ADVANCE_RX_PTR(priv->rx_write);
462 	}
463 	spin_lock_irqsave(&priv->meth_lock, flags);
464 	/* In case there was underflow, and Rx DMA was disabled */
465 	priv->dma_ctrl |= METH_DMA_RX_INT_EN | METH_DMA_RX_EN;
466 	mace->eth.dma_ctrl = priv->dma_ctrl;
467 	mace->eth.int_stat = METH_INT_RX_THRESHOLD;
468 	spin_unlock_irqrestore(&priv->meth_lock, flags);
469 }
470 
471 static int meth_tx_full(struct net_device *dev)
472 {
473 	struct meth_private *priv = netdev_priv(dev);
474 
475 	return priv->tx_count >= TX_RING_ENTRIES - 1;
476 }
477 
478 static void meth_tx_cleanup(struct net_device* dev, unsigned long int_status)
479 {
480 	struct meth_private *priv = netdev_priv(dev);
481 	unsigned long status, flags;
482 	struct sk_buff *skb;
483 	unsigned long rptr = (int_status&TX_INFO_RPTR) >> 16;
484 
485 	spin_lock_irqsave(&priv->meth_lock, flags);
486 
487 	/* Stop DMA notification */
488 	priv->dma_ctrl &= ~(METH_DMA_TX_INT_EN);
489 	mace->eth.dma_ctrl = priv->dma_ctrl;
490 
491 	while (priv->tx_read != rptr) {
492 		skb = priv->tx_skbs[priv->tx_read];
493 		status = priv->tx_ring[priv->tx_read].header.raw;
494 #if MFE_DEBUG>=1
495 		if (priv->tx_read == priv->tx_write)
496 			DPRINTK("Auchi! tx_read=%d,tx_write=%d,rptr=%d?\n", priv->tx_read, priv->tx_write,rptr);
497 #endif
498 		if (status & METH_TX_ST_DONE) {
499 			if (status & METH_TX_ST_SUCCESS){
500 				dev->stats.tx_packets++;
501 				dev->stats.tx_bytes += skb->len;
502 			} else {
503 				dev->stats.tx_errors++;
504 #if MFE_DEBUG>=1
505 				DPRINTK("TX error: status=%016lx <",status);
506 				if(status & METH_TX_ST_SUCCESS)
507 					printk(" SUCCESS");
508 				if(status & METH_TX_ST_TOOLONG)
509 					printk(" TOOLONG");
510 				if(status & METH_TX_ST_UNDERRUN)
511 					printk(" UNDERRUN");
512 				if(status & METH_TX_ST_EXCCOLL)
513 					printk(" EXCCOLL");
514 				if(status & METH_TX_ST_DEFER)
515 					printk(" DEFER");
516 				if(status & METH_TX_ST_LATECOLL)
517 					printk(" LATECOLL");
518 				printk(" >\n");
519 #endif
520 			}
521 		} else {
522 			DPRINTK("RPTR points us here, but packet not done?\n");
523 			break;
524 		}
525 		dev_kfree_skb_irq(skb);
526 		priv->tx_skbs[priv->tx_read] = NULL;
527 		priv->tx_ring[priv->tx_read].header.raw = 0;
528 		priv->tx_read = (priv->tx_read+1)&(TX_RING_ENTRIES-1);
529 		priv->tx_count--;
530 	}
531 
532 	/* wake up queue if it was stopped */
533 	if (netif_queue_stopped(dev) && !meth_tx_full(dev)) {
534 		netif_wake_queue(dev);
535 	}
536 
537 	mace->eth.int_stat = METH_INT_TX_EMPTY | METH_INT_TX_PKT;
538 	spin_unlock_irqrestore(&priv->meth_lock, flags);
539 }
540 
541 static void meth_error(struct net_device* dev, unsigned status)
542 {
543 	struct meth_private *priv = netdev_priv(dev);
544 	unsigned long flags;
545 
546 	printk(KERN_WARNING "meth: error status: 0x%08x\n",status);
547 	/* check for errors too... */
548 	if (status & (METH_INT_TX_LINK_FAIL))
549 		printk(KERN_WARNING "meth: link failure\n");
550 	/* Should I do full reset in this case? */
551 	if (status & (METH_INT_MEM_ERROR))
552 		printk(KERN_WARNING "meth: memory error\n");
553 	if (status & (METH_INT_TX_ABORT))
554 		printk(KERN_WARNING "meth: aborted\n");
555 	if (status & (METH_INT_RX_OVERFLOW))
556 		printk(KERN_WARNING "meth: Rx overflow\n");
557 	if (status & (METH_INT_RX_UNDERFLOW)) {
558 		printk(KERN_WARNING "meth: Rx underflow\n");
559 		spin_lock_irqsave(&priv->meth_lock, flags);
560 		mace->eth.int_stat = METH_INT_RX_UNDERFLOW;
561 		/* more underflow interrupts will be delivered,
562 		 * effectively throwing us into an infinite loop.
563 		 *  Thus I stop processing Rx in this case. */
564 		priv->dma_ctrl &= ~METH_DMA_RX_EN;
565 		mace->eth.dma_ctrl = priv->dma_ctrl;
566 		DPRINTK("Disabled meth Rx DMA temporarily\n");
567 		spin_unlock_irqrestore(&priv->meth_lock, flags);
568 	}
569 	mace->eth.int_stat = METH_INT_ERROR;
570 }
571 
572 /*
573  * The typical interrupt entry point
574  */
575 static irqreturn_t meth_interrupt(int irq, void *dev_id)
576 {
577 	struct net_device *dev = (struct net_device *)dev_id;
578 	struct meth_private *priv = netdev_priv(dev);
579 	unsigned long status;
580 
581 	status = mace->eth.int_stat;
582 	while (status & 0xff) {
583 		/* First handle errors - if we get Rx underflow,
584 		 * Rx DMA will be disabled, and Rx handler will reenable
585 		 * it. I don't think it's possible to get Rx underflow,
586 		 * without getting Rx interrupt */
587 		if (status & METH_INT_ERROR) {
588 			meth_error(dev, status);
589 		}
590 		if (status & (METH_INT_TX_EMPTY | METH_INT_TX_PKT)) {
591 			/* a transmission is over: free the skb */
592 			meth_tx_cleanup(dev, status);
593 		}
594 		if (status & METH_INT_RX_THRESHOLD) {
595 			if (!(priv->dma_ctrl & METH_DMA_RX_INT_EN))
596 				break;
597 			/* send it to meth_rx for handling */
598 			meth_rx(dev, status);
599 		}
600 		status = mace->eth.int_stat;
601 	}
602 
603 	return IRQ_HANDLED;
604 }
605 
606 /*
607  * Transmits packets that fit into TX descriptor (are <=120B)
608  */
609 static void meth_tx_short_prepare(struct meth_private *priv,
610 				  struct sk_buff *skb)
611 {
612 	tx_packet *desc = &priv->tx_ring[priv->tx_write];
613 	int len = (skb->len < ETH_ZLEN) ? ETH_ZLEN : skb->len;
614 
615 	desc->header.raw = METH_TX_CMD_INT_EN | (len-1) | ((128-len) << 16);
616 	/* maybe I should set whole thing to 0 first... */
617 	skb_copy_from_linear_data(skb, desc->data.dt + (120 - len), skb->len);
618 	if (skb->len < len)
619 		memset(desc->data.dt + 120 - len + skb->len, 0, len-skb->len);
620 }
621 #define TX_CATBUF1 BIT(25)
622 static void meth_tx_1page_prepare(struct meth_private *priv,
623 				  struct sk_buff *skb)
624 {
625 	tx_packet *desc = &priv->tx_ring[priv->tx_write];
626 	void *buffer_data = (void *)(((unsigned long)skb->data + 7) & ~7);
627 	int unaligned_len = (int)((unsigned long)buffer_data - (unsigned long)skb->data);
628 	int buffer_len = skb->len - unaligned_len;
629 	dma_addr_t catbuf;
630 
631 	desc->header.raw = METH_TX_CMD_INT_EN | TX_CATBUF1 | (skb->len - 1);
632 
633 	/* unaligned part */
634 	if (unaligned_len) {
635 		skb_copy_from_linear_data(skb, desc->data.dt + (120 - unaligned_len),
636 			      unaligned_len);
637 		desc->header.raw |= (128 - unaligned_len) << 16;
638 	}
639 
640 	/* first page */
641 	catbuf = dma_map_single(NULL, buffer_data, buffer_len,
642 				DMA_TO_DEVICE);
643 	desc->data.cat_buf[0].form.start_addr = catbuf >> 3;
644 	desc->data.cat_buf[0].form.len = buffer_len - 1;
645 }
646 #define TX_CATBUF2 BIT(26)
647 static void meth_tx_2page_prepare(struct meth_private *priv,
648 				  struct sk_buff *skb)
649 {
650 	tx_packet *desc = &priv->tx_ring[priv->tx_write];
651 	void *buffer1_data = (void *)(((unsigned long)skb->data + 7) & ~7);
652 	void *buffer2_data = (void *)PAGE_ALIGN((unsigned long)skb->data);
653 	int unaligned_len = (int)((unsigned long)buffer1_data - (unsigned long)skb->data);
654 	int buffer1_len = (int)((unsigned long)buffer2_data - (unsigned long)buffer1_data);
655 	int buffer2_len = skb->len - buffer1_len - unaligned_len;
656 	dma_addr_t catbuf1, catbuf2;
657 
658 	desc->header.raw = METH_TX_CMD_INT_EN | TX_CATBUF1 | TX_CATBUF2| (skb->len - 1);
659 	/* unaligned part */
660 	if (unaligned_len){
661 		skb_copy_from_linear_data(skb, desc->data.dt + (120 - unaligned_len),
662 			      unaligned_len);
663 		desc->header.raw |= (128 - unaligned_len) << 16;
664 	}
665 
666 	/* first page */
667 	catbuf1 = dma_map_single(NULL, buffer1_data, buffer1_len,
668 				 DMA_TO_DEVICE);
669 	desc->data.cat_buf[0].form.start_addr = catbuf1 >> 3;
670 	desc->data.cat_buf[0].form.len = buffer1_len - 1;
671 	/* second page */
672 	catbuf2 = dma_map_single(NULL, buffer2_data, buffer2_len,
673 				 DMA_TO_DEVICE);
674 	desc->data.cat_buf[1].form.start_addr = catbuf2 >> 3;
675 	desc->data.cat_buf[1].form.len = buffer2_len - 1;
676 }
677 
678 static void meth_add_to_tx_ring(struct meth_private *priv, struct sk_buff *skb)
679 {
680 	/* Remember the skb, so we can free it at interrupt time */
681 	priv->tx_skbs[priv->tx_write] = skb;
682 	if (skb->len <= 120) {
683 		/* Whole packet fits into descriptor */
684 		meth_tx_short_prepare(priv, skb);
685 	} else if (PAGE_ALIGN((unsigned long)skb->data) !=
686 		   PAGE_ALIGN((unsigned long)skb->data + skb->len - 1)) {
687 		/* Packet crosses page boundary */
688 		meth_tx_2page_prepare(priv, skb);
689 	} else {
690 		/* Packet is in one page */
691 		meth_tx_1page_prepare(priv, skb);
692 	}
693 	priv->tx_write = (priv->tx_write + 1) & (TX_RING_ENTRIES - 1);
694 	mace->eth.tx_info = priv->tx_write;
695 	priv->tx_count++;
696 }
697 
698 /*
699  * Transmit a packet (called by the kernel)
700  */
701 static int meth_tx(struct sk_buff *skb, struct net_device *dev)
702 {
703 	struct meth_private *priv = netdev_priv(dev);
704 	unsigned long flags;
705 
706 	spin_lock_irqsave(&priv->meth_lock, flags);
707 	/* Stop DMA notification */
708 	priv->dma_ctrl &= ~(METH_DMA_TX_INT_EN);
709 	mace->eth.dma_ctrl = priv->dma_ctrl;
710 
711 	meth_add_to_tx_ring(priv, skb);
712 	dev->trans_start = jiffies; /* save the timestamp */
713 
714 	/* If TX ring is full, tell the upper layer to stop sending packets */
715 	if (meth_tx_full(dev)) {
716 	        printk(KERN_DEBUG "TX full: stopping\n");
717 		netif_stop_queue(dev);
718 	}
719 
720 	/* Restart DMA notification */
721 	priv->dma_ctrl |= METH_DMA_TX_INT_EN;
722 	mace->eth.dma_ctrl = priv->dma_ctrl;
723 
724 	spin_unlock_irqrestore(&priv->meth_lock, flags);
725 
726 	return NETDEV_TX_OK;
727 }
728 
729 /*
730  * Deal with a transmit timeout.
731  */
732 static void meth_tx_timeout(struct net_device *dev)
733 {
734 	struct meth_private *priv = netdev_priv(dev);
735 	unsigned long flags;
736 
737 	printk(KERN_WARNING "%s: transmit timed out\n", dev->name);
738 
739 	/* Protect against concurrent rx interrupts */
740 	spin_lock_irqsave(&priv->meth_lock,flags);
741 
742 	/* Try to reset the interface. */
743 	meth_reset(dev);
744 
745 	dev->stats.tx_errors++;
746 
747 	/* Clear all rings */
748 	meth_free_tx_ring(priv);
749 	meth_free_rx_ring(priv);
750 	meth_init_tx_ring(priv);
751 	meth_init_rx_ring(priv);
752 
753 	/* Restart dma */
754 	priv->dma_ctrl |= METH_DMA_TX_EN | METH_DMA_RX_EN | METH_DMA_RX_INT_EN;
755 	mace->eth.dma_ctrl = priv->dma_ctrl;
756 
757 	/* Enable interrupt */
758 	spin_unlock_irqrestore(&priv->meth_lock, flags);
759 
760 	dev->trans_start = jiffies; /* prevent tx timeout */
761 	netif_wake_queue(dev);
762 }
763 
764 /*
765  * Ioctl commands
766  */
767 static int meth_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
768 {
769 	/* XXX Not yet implemented */
770 	switch(cmd) {
771 	case SIOCGMIIPHY:
772 	case SIOCGMIIREG:
773 	case SIOCSMIIREG:
774 	default:
775 		return -EOPNOTSUPP;
776 	}
777 }
778 
779 static void meth_set_rx_mode(struct net_device *dev)
780 {
781 	struct meth_private *priv = netdev_priv(dev);
782 	unsigned long flags;
783 
784 	netif_stop_queue(dev);
785 	spin_lock_irqsave(&priv->meth_lock, flags);
786 	priv->mac_ctrl &= ~METH_PROMISC;
787 
788 	if (dev->flags & IFF_PROMISC) {
789 		priv->mac_ctrl |= METH_PROMISC;
790 		priv->mcast_filter = 0xffffffffffffffffUL;
791 	} else if ((netdev_mc_count(dev) > METH_MCF_LIMIT) ||
792 		   (dev->flags & IFF_ALLMULTI)) {
793 		priv->mac_ctrl |= METH_ACCEPT_AMCAST;
794 		priv->mcast_filter = 0xffffffffffffffffUL;
795 	} else {
796 		struct netdev_hw_addr *ha;
797 		priv->mac_ctrl |= METH_ACCEPT_MCAST;
798 
799 		netdev_for_each_mc_addr(ha, dev)
800 			set_bit((ether_crc(ETH_ALEN, ha->addr) >> 26),
801 			        (volatile unsigned long *)&priv->mcast_filter);
802 	}
803 
804 	/* Write the changes to the chip registers. */
805 	mace->eth.mac_ctrl = priv->mac_ctrl;
806 	mace->eth.mcast_filter = priv->mcast_filter;
807 
808 	/* Done! */
809 	spin_unlock_irqrestore(&priv->meth_lock, flags);
810 	netif_wake_queue(dev);
811 }
812 
813 static const struct net_device_ops meth_netdev_ops = {
814 	.ndo_open		= meth_open,
815 	.ndo_stop		= meth_release,
816 	.ndo_start_xmit		= meth_tx,
817 	.ndo_do_ioctl		= meth_ioctl,
818 	.ndo_tx_timeout		= meth_tx_timeout,
819 	.ndo_change_mtu		= eth_change_mtu,
820 	.ndo_validate_addr	= eth_validate_addr,
821 	.ndo_set_mac_address	= eth_mac_addr,
822 	.ndo_set_rx_mode    	= meth_set_rx_mode,
823 };
824 
825 /*
826  * The init function.
827  */
828 static int meth_probe(struct platform_device *pdev)
829 {
830 	struct net_device *dev;
831 	struct meth_private *priv;
832 	int err;
833 
834 	dev = alloc_etherdev(sizeof(struct meth_private));
835 	if (!dev)
836 		return -ENOMEM;
837 
838 	dev->netdev_ops		= &meth_netdev_ops;
839 	dev->watchdog_timeo	= timeout;
840 	dev->irq		= MACE_ETHERNET_IRQ;
841 	dev->base_addr		= (unsigned long)&mace->eth;
842 	memcpy(dev->dev_addr, o2meth_eaddr, 6);
843 
844 	priv = netdev_priv(dev);
845 	spin_lock_init(&priv->meth_lock);
846 	SET_NETDEV_DEV(dev, &pdev->dev);
847 
848 	err = register_netdev(dev);
849 	if (err) {
850 		free_netdev(dev);
851 		return err;
852 	}
853 
854 	printk(KERN_INFO "%s: SGI MACE Ethernet rev. %d\n",
855 	       dev->name, (unsigned int)(mace->eth.mac_ctrl >> 29));
856 	return 0;
857 }
858 
859 static int __exit meth_remove(struct platform_device *pdev)
860 {
861 	struct net_device *dev = platform_get_drvdata(pdev);
862 
863 	unregister_netdev(dev);
864 	free_netdev(dev);
865 
866 	return 0;
867 }
868 
869 static struct platform_driver meth_driver = {
870 	.probe	= meth_probe,
871 	.remove	= __exit_p(meth_remove),
872 	.driver = {
873 		.name	= "meth",
874 		.owner	= THIS_MODULE,
875 	}
876 };
877 
878 module_platform_driver(meth_driver);
879 
880 MODULE_AUTHOR("Ilya Volynets <ilya@theIlya.com>");
881 MODULE_DESCRIPTION("SGI O2 Builtin Fast Ethernet driver");
882 MODULE_LICENSE("GPL");
883 MODULE_ALIAS("platform:meth");
884