xref: /linux/drivers/net/wan/hd64572.c (revision 60e13231561b3a4c5269bfa1ef6c0569ad6f28ec)
1 /*
2  * Hitachi (now Renesas) SCA-II HD64572 driver for Linux
3  *
4  * Copyright (C) 1998-2008 Krzysztof Halasa <khc@pm.waw.pl>
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of version 2 of the GNU General Public License
8  * as published by the Free Software Foundation.
9  *
10  * Source of information: HD64572 SCA-II User's Manual
11  *
12  * We use the following SCA memory map:
13  *
14  * Packet buffer descriptor rings - starting from card->rambase:
15  * rx_ring_buffers * sizeof(pkt_desc) = logical channel #0 RX ring
16  * tx_ring_buffers * sizeof(pkt_desc) = logical channel #0 TX ring
17  * rx_ring_buffers * sizeof(pkt_desc) = logical channel #1 RX ring (if used)
18  * tx_ring_buffers * sizeof(pkt_desc) = logical channel #1 TX ring (if used)
19  *
20  * Packet data buffers - starting from card->rambase + buff_offset:
21  * rx_ring_buffers * HDLC_MAX_MRU     = logical channel #0 RX buffers
22  * tx_ring_buffers * HDLC_MAX_MRU     = logical channel #0 TX buffers
23  * rx_ring_buffers * HDLC_MAX_MRU     = logical channel #0 RX buffers (if used)
24  * tx_ring_buffers * HDLC_MAX_MRU     = logical channel #0 TX buffers (if used)
25  */
26 
27 #include <linux/bitops.h>
28 #include <linux/errno.h>
29 #include <linux/fcntl.h>
30 #include <linux/hdlc.h>
31 #include <linux/in.h>
32 #include <linux/init.h>
33 #include <linux/interrupt.h>
34 #include <linux/ioport.h>
35 #include <linux/jiffies.h>
36 #include <linux/kernel.h>
37 #include <linux/module.h>
38 #include <linux/netdevice.h>
39 #include <linux/skbuff.h>
40 #include <linux/string.h>
41 #include <linux/types.h>
42 #include <asm/io.h>
43 #include <asm/system.h>
44 #include <asm/uaccess.h>
45 #include "hd64572.h"
46 
47 #define NAPI_WEIGHT		16
48 
49 #define get_msci(port)	  (port->chan ?   MSCI1_OFFSET :   MSCI0_OFFSET)
50 #define get_dmac_rx(port) (port->chan ? DMAC1RX_OFFSET : DMAC0RX_OFFSET)
51 #define get_dmac_tx(port) (port->chan ? DMAC1TX_OFFSET : DMAC0TX_OFFSET)
52 
53 #define sca_in(reg, card)	     readb(card->scabase + (reg))
54 #define sca_out(value, reg, card)    writeb(value, card->scabase + (reg))
55 #define sca_inw(reg, card)	     readw(card->scabase + (reg))
56 #define sca_outw(value, reg, card)   writew(value, card->scabase + (reg))
57 #define sca_inl(reg, card)	     readl(card->scabase + (reg))
58 #define sca_outl(value, reg, card)   writel(value, card->scabase + (reg))
59 
60 static int sca_poll(struct napi_struct *napi, int budget);
61 
62 static inline port_t* dev_to_port(struct net_device *dev)
63 {
64 	return dev_to_hdlc(dev)->priv;
65 }
66 
67 static inline void enable_intr(port_t *port)
68 {
69 	/* enable DMIB and MSCI RXINTA interrupts */
70 	sca_outl(sca_inl(IER0, port->card) |
71 		 (port->chan ? 0x08002200 : 0x00080022), IER0, port->card);
72 }
73 
74 static inline void disable_intr(port_t *port)
75 {
76 	sca_outl(sca_inl(IER0, port->card) &
77 		 (port->chan ? 0x00FF00FF : 0xFF00FF00), IER0, port->card);
78 }
79 
80 static inline u16 desc_abs_number(port_t *port, u16 desc, int transmit)
81 {
82 	u16 rx_buffs = port->card->rx_ring_buffers;
83 	u16 tx_buffs = port->card->tx_ring_buffers;
84 
85 	desc %= (transmit ? tx_buffs : rx_buffs); // called with "X + 1" etc.
86 	return port->chan * (rx_buffs + tx_buffs) + transmit * rx_buffs + desc;
87 }
88 
89 
90 static inline u16 desc_offset(port_t *port, u16 desc, int transmit)
91 {
92 	/* Descriptor offset always fits in 16 bits */
93 	return desc_abs_number(port, desc, transmit) * sizeof(pkt_desc);
94 }
95 
96 
97 static inline pkt_desc __iomem *desc_address(port_t *port, u16 desc,
98 					     int transmit)
99 {
100 	return (pkt_desc __iomem *)(port->card->rambase +
101 				    desc_offset(port, desc, transmit));
102 }
103 
104 
105 static inline u32 buffer_offset(port_t *port, u16 desc, int transmit)
106 {
107 	return port->card->buff_offset +
108 		desc_abs_number(port, desc, transmit) * (u32)HDLC_MAX_MRU;
109 }
110 
111 
112 static inline void sca_set_carrier(port_t *port)
113 {
114 	if (!(sca_in(get_msci(port) + ST3, port->card) & ST3_DCD)) {
115 #ifdef DEBUG_LINK
116 		printk(KERN_DEBUG "%s: sca_set_carrier on\n",
117 		       port->netdev.name);
118 #endif
119 		netif_carrier_on(port->netdev);
120 	} else {
121 #ifdef DEBUG_LINK
122 		printk(KERN_DEBUG "%s: sca_set_carrier off\n",
123 		       port->netdev.name);
124 #endif
125 		netif_carrier_off(port->netdev);
126 	}
127 }
128 
129 
130 static void sca_init_port(port_t *port)
131 {
132 	card_t *card = port->card;
133 	u16 dmac_rx = get_dmac_rx(port), dmac_tx = get_dmac_tx(port);
134 	int transmit, i;
135 
136 	port->rxin = 0;
137 	port->txin = 0;
138 	port->txlast = 0;
139 
140 	for (transmit = 0; transmit < 2; transmit++) {
141 		u16 buffs = transmit ? card->tx_ring_buffers
142 			: card->rx_ring_buffers;
143 
144 		for (i = 0; i < buffs; i++) {
145 			pkt_desc __iomem *desc = desc_address(port, i, transmit);
146 			u16 chain_off = desc_offset(port, i + 1, transmit);
147 			u32 buff_off = buffer_offset(port, i, transmit);
148 
149 			writel(chain_off, &desc->cp);
150 			writel(buff_off, &desc->bp);
151 			writew(0, &desc->len);
152 			writeb(0, &desc->stat);
153 		}
154 	}
155 
156 	/* DMA disable - to halt state */
157 	sca_out(0, DSR_RX(port->chan), card);
158 	sca_out(0, DSR_TX(port->chan), card);
159 
160 	/* software ABORT - to initial state */
161 	sca_out(DCR_ABORT, DCR_RX(port->chan), card);
162 	sca_out(DCR_ABORT, DCR_TX(port->chan), card);
163 
164 	/* current desc addr */
165 	sca_outl(desc_offset(port, 0, 0), dmac_rx + CDAL, card);
166 	sca_outl(desc_offset(port, card->tx_ring_buffers - 1, 0),
167 		 dmac_rx + EDAL, card);
168 	sca_outl(desc_offset(port, 0, 1), dmac_tx + CDAL, card);
169 	sca_outl(desc_offset(port, 0, 1), dmac_tx + EDAL, card);
170 
171 	/* clear frame end interrupt counter */
172 	sca_out(DCR_CLEAR_EOF, DCR_RX(port->chan), card);
173 	sca_out(DCR_CLEAR_EOF, DCR_TX(port->chan), card);
174 
175 	/* Receive */
176 	sca_outw(HDLC_MAX_MRU, dmac_rx + BFLL, card); /* set buffer length */
177 	sca_out(0x14, DMR_RX(port->chan), card); /* Chain mode, Multi-frame */
178 	sca_out(DIR_EOME, DIR_RX(port->chan), card); /* enable interrupts */
179 	sca_out(DSR_DE, DSR_RX(port->chan), card); /* DMA enable */
180 
181 	/* Transmit */
182 	sca_out(0x14, DMR_TX(port->chan), card); /* Chain mode, Multi-frame */
183 	sca_out(DIR_EOME, DIR_TX(port->chan), card); /* enable interrupts */
184 
185 	sca_set_carrier(port);
186 	netif_napi_add(port->netdev, &port->napi, sca_poll, NAPI_WEIGHT);
187 }
188 
189 
190 /* MSCI interrupt service */
191 static inline void sca_msci_intr(port_t *port)
192 {
193 	u16 msci = get_msci(port);
194 	card_t* card = port->card;
195 
196 	if (sca_in(msci + ST1, card) & ST1_CDCD) {
197 		/* Reset MSCI CDCD status bit */
198 		sca_out(ST1_CDCD, msci + ST1, card);
199 		sca_set_carrier(port);
200 	}
201 }
202 
203 
204 static inline void sca_rx(card_t *card, port_t *port, pkt_desc __iomem *desc,
205 			  u16 rxin)
206 {
207 	struct net_device *dev = port->netdev;
208 	struct sk_buff *skb;
209 	u16 len;
210 	u32 buff;
211 
212 	len = readw(&desc->len);
213 	skb = dev_alloc_skb(len);
214 	if (!skb) {
215 		dev->stats.rx_dropped++;
216 		return;
217 	}
218 
219 	buff = buffer_offset(port, rxin, 0);
220 	memcpy_fromio(skb->data, card->rambase + buff, len);
221 
222 	skb_put(skb, len);
223 #ifdef DEBUG_PKT
224 	printk(KERN_DEBUG "%s RX(%i):", dev->name, skb->len);
225 	debug_frame(skb);
226 #endif
227 	dev->stats.rx_packets++;
228 	dev->stats.rx_bytes += skb->len;
229 	skb->protocol = hdlc_type_trans(skb, dev);
230 	netif_receive_skb(skb);
231 }
232 
233 
234 /* Receive DMA service */
235 static inline int sca_rx_done(port_t *port, int budget)
236 {
237 	struct net_device *dev = port->netdev;
238 	u16 dmac = get_dmac_rx(port);
239 	card_t *card = port->card;
240 	u8 stat = sca_in(DSR_RX(port->chan), card); /* read DMA Status */
241 	int received = 0;
242 
243 	/* Reset DSR status bits */
244 	sca_out((stat & (DSR_EOT | DSR_EOM | DSR_BOF | DSR_COF)) | DSR_DWE,
245 		DSR_RX(port->chan), card);
246 
247 	if (stat & DSR_BOF)
248 		/* Dropped one or more frames */
249 		dev->stats.rx_over_errors++;
250 
251 	while (received < budget) {
252 		u32 desc_off = desc_offset(port, port->rxin, 0);
253 		pkt_desc __iomem *desc;
254 		u32 cda = sca_inl(dmac + CDAL, card);
255 
256 		if ((cda >= desc_off) && (cda < desc_off + sizeof(pkt_desc)))
257 			break;	/* No frame received */
258 
259 		desc = desc_address(port, port->rxin, 0);
260 		stat = readb(&desc->stat);
261 		if (!(stat & ST_RX_EOM))
262 			port->rxpart = 1; /* partial frame received */
263 		else if ((stat & ST_ERROR_MASK) || port->rxpart) {
264 			dev->stats.rx_errors++;
265 			if (stat & ST_RX_OVERRUN)
266 				dev->stats.rx_fifo_errors++;
267 			else if ((stat & (ST_RX_SHORT | ST_RX_ABORT |
268 					  ST_RX_RESBIT)) || port->rxpart)
269 				dev->stats.rx_frame_errors++;
270 			else if (stat & ST_RX_CRC)
271 				dev->stats.rx_crc_errors++;
272 			if (stat & ST_RX_EOM)
273 				port->rxpart = 0; /* received last fragment */
274 		} else {
275 			sca_rx(card, port, desc, port->rxin);
276 			received++;
277 		}
278 
279 		/* Set new error descriptor address */
280 		sca_outl(desc_off, dmac + EDAL, card);
281 		port->rxin = (port->rxin + 1) % card->rx_ring_buffers;
282 	}
283 
284 	/* make sure RX DMA is enabled */
285 	sca_out(DSR_DE, DSR_RX(port->chan), card);
286 	return received;
287 }
288 
289 
290 /* Transmit DMA service */
291 static inline void sca_tx_done(port_t *port)
292 {
293 	struct net_device *dev = port->netdev;
294 	card_t* card = port->card;
295 	u8 stat;
296 	unsigned count = 0;
297 
298 	spin_lock(&port->lock);
299 
300 	stat = sca_in(DSR_TX(port->chan), card); /* read DMA Status */
301 
302 	/* Reset DSR status bits */
303 	sca_out((stat & (DSR_EOT | DSR_EOM | DSR_BOF | DSR_COF)) | DSR_DWE,
304 		DSR_TX(port->chan), card);
305 
306 	while (1) {
307 		pkt_desc __iomem *desc = desc_address(port, port->txlast, 1);
308 		u8 stat = readb(&desc->stat);
309 
310 		if (!(stat & ST_TX_OWNRSHP))
311 			break; /* not yet transmitted */
312 		if (stat & ST_TX_UNDRRUN) {
313 			dev->stats.tx_errors++;
314 			dev->stats.tx_fifo_errors++;
315 		} else {
316 			dev->stats.tx_packets++;
317 			dev->stats.tx_bytes += readw(&desc->len);
318 		}
319 		writeb(0, &desc->stat);	/* Free descriptor */
320 		count++;
321 		port->txlast = (port->txlast + 1) % card->tx_ring_buffers;
322 	}
323 
324 	if (count)
325 		netif_wake_queue(dev);
326 	spin_unlock(&port->lock);
327 }
328 
329 
330 static int sca_poll(struct napi_struct *napi, int budget)
331 {
332 	port_t *port = container_of(napi, port_t, napi);
333 	u32 isr0 = sca_inl(ISR0, port->card);
334 	int received = 0;
335 
336 	if (isr0 & (port->chan ? 0x08000000 : 0x00080000))
337 		sca_msci_intr(port);
338 
339 	if (isr0 & (port->chan ? 0x00002000 : 0x00000020))
340 		sca_tx_done(port);
341 
342 	if (isr0 & (port->chan ? 0x00000200 : 0x00000002))
343 		received = sca_rx_done(port, budget);
344 
345 	if (received < budget) {
346 		napi_complete(napi);
347 		enable_intr(port);
348 	}
349 
350 	return received;
351 }
352 
353 static irqreturn_t sca_intr(int irq, void *dev_id)
354 {
355 	card_t *card = dev_id;
356 	u32 isr0 = sca_inl(ISR0, card);
357 	int i, handled = 0;
358 
359 	for (i = 0; i < 2; i++) {
360 		port_t *port = get_port(card, i);
361 		if (port && (isr0 & (i ? 0x08002200 : 0x00080022))) {
362 			handled = 1;
363 			disable_intr(port);
364 			napi_schedule(&port->napi);
365 		}
366 	}
367 
368 	return IRQ_RETVAL(handled);
369 }
370 
371 
372 static void sca_set_port(port_t *port)
373 {
374 	card_t* card = port->card;
375 	u16 msci = get_msci(port);
376 	u8 md2 = sca_in(msci + MD2, card);
377 	unsigned int tmc, br = 10, brv = 1024;
378 
379 
380 	if (port->settings.clock_rate > 0) {
381 		/* Try lower br for better accuracy*/
382 		do {
383 			br--;
384 			brv >>= 1; /* brv = 2^9 = 512 max in specs */
385 
386 			/* Baud Rate = CLOCK_BASE / TMC / 2^BR */
387 			tmc = CLOCK_BASE / brv / port->settings.clock_rate;
388 		}while (br > 1 && tmc <= 128);
389 
390 		if (tmc < 1) {
391 			tmc = 1;
392 			br = 0;	/* For baud=CLOCK_BASE we use tmc=1 br=0 */
393 			brv = 1;
394 		} else if (tmc > 255)
395 			tmc = 256; /* tmc=0 means 256 - low baud rates */
396 
397 		port->settings.clock_rate = CLOCK_BASE / brv / tmc;
398 	} else {
399 		br = 9; /* Minimum clock rate */
400 		tmc = 256;	/* 8bit = 0 */
401 		port->settings.clock_rate = CLOCK_BASE / (256 * 512);
402 	}
403 
404 	port->rxs = (port->rxs & ~CLK_BRG_MASK) | br;
405 	port->txs = (port->txs & ~CLK_BRG_MASK) | br;
406 	port->tmc = tmc;
407 
408 	/* baud divisor - time constant*/
409 	sca_out(port->tmc, msci + TMCR, card);
410 	sca_out(port->tmc, msci + TMCT, card);
411 
412 	/* Set BRG bits */
413 	sca_out(port->rxs, msci + RXS, card);
414 	sca_out(port->txs, msci + TXS, card);
415 
416 	if (port->settings.loopback)
417 		md2 |= MD2_LOOPBACK;
418 	else
419 		md2 &= ~MD2_LOOPBACK;
420 
421 	sca_out(md2, msci + MD2, card);
422 
423 }
424 
425 
426 static void sca_open(struct net_device *dev)
427 {
428 	port_t *port = dev_to_port(dev);
429 	card_t* card = port->card;
430 	u16 msci = get_msci(port);
431 	u8 md0, md2;
432 
433 	switch(port->encoding) {
434 	case ENCODING_NRZ:	md2 = MD2_NRZ;		break;
435 	case ENCODING_NRZI:	md2 = MD2_NRZI;		break;
436 	case ENCODING_FM_MARK:	md2 = MD2_FM_MARK;	break;
437 	case ENCODING_FM_SPACE:	md2 = MD2_FM_SPACE;	break;
438 	default:		md2 = MD2_MANCHESTER;
439 	}
440 
441 	if (port->settings.loopback)
442 		md2 |= MD2_LOOPBACK;
443 
444 	switch(port->parity) {
445 	case PARITY_CRC16_PR0:	     md0 = MD0_HDLC | MD0_CRC_16_0;  break;
446 	case PARITY_CRC16_PR1:	     md0 = MD0_HDLC | MD0_CRC_16;    break;
447 	case PARITY_CRC32_PR1_CCITT: md0 = MD0_HDLC | MD0_CRC_ITU32; break;
448 	case PARITY_CRC16_PR1_CCITT: md0 = MD0_HDLC | MD0_CRC_ITU;   break;
449 	default:		     md0 = MD0_HDLC | MD0_CRC_NONE;
450 	}
451 
452 	sca_out(CMD_RESET, msci + CMD, card);
453 	sca_out(md0, msci + MD0, card);
454 	sca_out(0x00, msci + MD1, card); /* no address field check */
455 	sca_out(md2, msci + MD2, card);
456 	sca_out(0x7E, msci + IDL, card); /* flag character 0x7E */
457 	/* Skip the rest of underrun frame */
458 	sca_out(CTL_IDLE | CTL_URCT | CTL_URSKP, msci + CTL, card);
459 	sca_out(0x0F, msci + RNR, card); /* +1=RX DMA activation condition */
460 	sca_out(0x3C, msci + TFS, card); /* +1 = TX start */
461 	sca_out(0x38, msci + TCR, card); /* =Critical TX DMA activ condition */
462 	sca_out(0x38, msci + TNR0, card); /* =TX DMA activation condition */
463 	sca_out(0x3F, msci + TNR1, card); /* +1=TX DMA deactivation condition*/
464 
465 /* We're using the following interrupts:
466    - RXINTA (DCD changes only)
467    - DMIB (EOM - single frame transfer complete)
468 */
469 	sca_outl(IE0_RXINTA | IE0_CDCD, msci + IE0, card);
470 
471 	sca_out(port->tmc, msci + TMCR, card);
472 	sca_out(port->tmc, msci + TMCT, card);
473 	sca_out(port->rxs, msci + RXS, card);
474 	sca_out(port->txs, msci + TXS, card);
475 	sca_out(CMD_TX_ENABLE, msci + CMD, card);
476 	sca_out(CMD_RX_ENABLE, msci + CMD, card);
477 
478 	sca_set_carrier(port);
479 	enable_intr(port);
480 	napi_enable(&port->napi);
481 	netif_start_queue(dev);
482 }
483 
484 
485 static void sca_close(struct net_device *dev)
486 {
487 	port_t *port = dev_to_port(dev);
488 
489 	/* reset channel */
490 	sca_out(CMD_RESET, get_msci(port) + CMD, port->card);
491 	disable_intr(port);
492 	napi_disable(&port->napi);
493 	netif_stop_queue(dev);
494 }
495 
496 
497 static int sca_attach(struct net_device *dev, unsigned short encoding,
498 		      unsigned short parity)
499 {
500 	if (encoding != ENCODING_NRZ &&
501 	    encoding != ENCODING_NRZI &&
502 	    encoding != ENCODING_FM_MARK &&
503 	    encoding != ENCODING_FM_SPACE &&
504 	    encoding != ENCODING_MANCHESTER)
505 		return -EINVAL;
506 
507 	if (parity != PARITY_NONE &&
508 	    parity != PARITY_CRC16_PR0 &&
509 	    parity != PARITY_CRC16_PR1 &&
510 	    parity != PARITY_CRC32_PR1_CCITT &&
511 	    parity != PARITY_CRC16_PR1_CCITT)
512 		return -EINVAL;
513 
514 	dev_to_port(dev)->encoding = encoding;
515 	dev_to_port(dev)->parity = parity;
516 	return 0;
517 }
518 
519 
520 #ifdef DEBUG_RINGS
521 static void sca_dump_rings(struct net_device *dev)
522 {
523 	port_t *port = dev_to_port(dev);
524 	card_t *card = port->card;
525 	u16 cnt;
526 
527 	printk(KERN_DEBUG "RX ring: CDA=%u EDA=%u DSR=%02X in=%u %sactive",
528 	       sca_inl(get_dmac_rx(port) + CDAL, card),
529 	       sca_inl(get_dmac_rx(port) + EDAL, card),
530 	       sca_in(DSR_RX(port->chan), card), port->rxin,
531 	       sca_in(DSR_RX(port->chan), card) & DSR_DE ? "" : "in");
532 	for (cnt = 0; cnt < port->card->rx_ring_buffers; cnt++)
533 		pr_cont(" %02X", readb(&(desc_address(port, cnt, 0)->stat)));
534 	pr_cont("\n");
535 
536 	printk(KERN_DEBUG "TX ring: CDA=%u EDA=%u DSR=%02X in=%u "
537 	       "last=%u %sactive",
538 	       sca_inl(get_dmac_tx(port) + CDAL, card),
539 	       sca_inl(get_dmac_tx(port) + EDAL, card),
540 	       sca_in(DSR_TX(port->chan), card), port->txin, port->txlast,
541 	       sca_in(DSR_TX(port->chan), card) & DSR_DE ? "" : "in");
542 
543 	for (cnt = 0; cnt < port->card->tx_ring_buffers; cnt++)
544 		pr_cont(" %02X", readb(&(desc_address(port, cnt, 1)->stat)));
545 	pr_cont("\n");
546 
547 	printk(KERN_DEBUG "MSCI: MD: %02x %02x %02x,"
548 	       " ST: %02x %02x %02x %02x %02x, FST: %02x CST: %02x %02x\n",
549 	       sca_in(get_msci(port) + MD0, card),
550 	       sca_in(get_msci(port) + MD1, card),
551 	       sca_in(get_msci(port) + MD2, card),
552 	       sca_in(get_msci(port) + ST0, card),
553 	       sca_in(get_msci(port) + ST1, card),
554 	       sca_in(get_msci(port) + ST2, card),
555 	       sca_in(get_msci(port) + ST3, card),
556 	       sca_in(get_msci(port) + ST4, card),
557 	       sca_in(get_msci(port) + FST, card),
558 	       sca_in(get_msci(port) + CST0, card),
559 	       sca_in(get_msci(port) + CST1, card));
560 
561 	printk(KERN_DEBUG "ILAR: %02x ISR: %08x %08x\n", sca_in(ILAR, card),
562 	       sca_inl(ISR0, card), sca_inl(ISR1, card));
563 }
564 #endif /* DEBUG_RINGS */
565 
566 
567 static netdev_tx_t sca_xmit(struct sk_buff *skb, struct net_device *dev)
568 {
569 	port_t *port = dev_to_port(dev);
570 	card_t *card = port->card;
571 	pkt_desc __iomem *desc;
572 	u32 buff, len;
573 
574 	spin_lock_irq(&port->lock);
575 
576 	desc = desc_address(port, port->txin + 1, 1);
577 	BUG_ON(readb(&desc->stat)); /* previous xmit should stop queue */
578 
579 #ifdef DEBUG_PKT
580 	printk(KERN_DEBUG "%s TX(%i):", dev->name, skb->len);
581 	debug_frame(skb);
582 #endif
583 
584 	desc = desc_address(port, port->txin, 1);
585 	buff = buffer_offset(port, port->txin, 1);
586 	len = skb->len;
587 	memcpy_toio(card->rambase + buff, skb->data, len);
588 
589 	writew(len, &desc->len);
590 	writeb(ST_TX_EOM, &desc->stat);
591 
592 	port->txin = (port->txin + 1) % card->tx_ring_buffers;
593 	sca_outl(desc_offset(port, port->txin, 1),
594 		 get_dmac_tx(port) + EDAL, card);
595 
596 	sca_out(DSR_DE, DSR_TX(port->chan), card); /* Enable TX DMA */
597 
598 	desc = desc_address(port, port->txin + 1, 1);
599 	if (readb(&desc->stat)) /* allow 1 packet gap */
600 		netif_stop_queue(dev);
601 
602 	spin_unlock_irq(&port->lock);
603 
604 	dev_kfree_skb(skb);
605 	return NETDEV_TX_OK;
606 }
607 
608 
609 static u32 __devinit sca_detect_ram(card_t *card, u8 __iomem *rambase,
610 				    u32 ramsize)
611 {
612 	/* Round RAM size to 32 bits, fill from end to start */
613 	u32 i = ramsize &= ~3;
614 
615 	do {
616 		i -= 4;
617 		writel(i ^ 0x12345678, rambase + i);
618 	} while (i > 0);
619 
620 	for (i = 0; i < ramsize ; i += 4) {
621 		if (readl(rambase + i) != (i ^ 0x12345678))
622 			break;
623 	}
624 
625 	return i;
626 }
627 
628 
629 static void __devinit sca_init(card_t *card, int wait_states)
630 {
631 	sca_out(wait_states, WCRL, card); /* Wait Control */
632 	sca_out(wait_states, WCRM, card);
633 	sca_out(wait_states, WCRH, card);
634 
635 	sca_out(0, DMER, card);	/* DMA Master disable */
636 	sca_out(0x03, PCR, card); /* DMA priority */
637 	sca_out(0, DSR_RX(0), card); /* DMA disable - to halt state */
638 	sca_out(0, DSR_TX(0), card);
639 	sca_out(0, DSR_RX(1), card);
640 	sca_out(0, DSR_TX(1), card);
641 	sca_out(DMER_DME, DMER, card); /* DMA Master enable */
642 }
643