xref: /openbmc/linux/drivers/net/wan/hd64572.c (revision 9cfc5c90)
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/interrupt.h>
33 #include <linux/ioport.h>
34 #include <linux/jiffies.h>
35 #include <linux/kernel.h>
36 #include <linux/module.h>
37 #include <linux/netdevice.h>
38 #include <linux/skbuff.h>
39 #include <linux/string.h>
40 #include <linux/types.h>
41 #include <asm/io.h>
42 #include <asm/uaccess.h>
43 #include "hd64572.h"
44 
45 #define NAPI_WEIGHT		16
46 
47 #define get_msci(port)	  (port->chan ?   MSCI1_OFFSET :   MSCI0_OFFSET)
48 #define get_dmac_rx(port) (port->chan ? DMAC1RX_OFFSET : DMAC0RX_OFFSET)
49 #define get_dmac_tx(port) (port->chan ? DMAC1TX_OFFSET : DMAC0TX_OFFSET)
50 
51 #define sca_in(reg, card)	     readb(card->scabase + (reg))
52 #define sca_out(value, reg, card)    writeb(value, card->scabase + (reg))
53 #define sca_inw(reg, card)	     readw(card->scabase + (reg))
54 #define sca_outw(value, reg, card)   writew(value, card->scabase + (reg))
55 #define sca_inl(reg, card)	     readl(card->scabase + (reg))
56 #define sca_outl(value, reg, card)   writel(value, card->scabase + (reg))
57 
58 static int sca_poll(struct napi_struct *napi, int budget);
59 
60 static inline port_t* dev_to_port(struct net_device *dev)
61 {
62 	return dev_to_hdlc(dev)->priv;
63 }
64 
65 static inline void enable_intr(port_t *port)
66 {
67 	/* enable DMIB and MSCI RXINTA interrupts */
68 	sca_outl(sca_inl(IER0, port->card) |
69 		 (port->chan ? 0x08002200 : 0x00080022), IER0, port->card);
70 }
71 
72 static inline void disable_intr(port_t *port)
73 {
74 	sca_outl(sca_inl(IER0, port->card) &
75 		 (port->chan ? 0x00FF00FF : 0xFF00FF00), IER0, port->card);
76 }
77 
78 static inline u16 desc_abs_number(port_t *port, u16 desc, int transmit)
79 {
80 	u16 rx_buffs = port->card->rx_ring_buffers;
81 	u16 tx_buffs = port->card->tx_ring_buffers;
82 
83 	desc %= (transmit ? tx_buffs : rx_buffs); // called with "X + 1" etc.
84 	return port->chan * (rx_buffs + tx_buffs) + transmit * rx_buffs + desc;
85 }
86 
87 
88 static inline u16 desc_offset(port_t *port, u16 desc, int transmit)
89 {
90 	/* Descriptor offset always fits in 16 bits */
91 	return desc_abs_number(port, desc, transmit) * sizeof(pkt_desc);
92 }
93 
94 
95 static inline pkt_desc __iomem *desc_address(port_t *port, u16 desc,
96 					     int transmit)
97 {
98 	return (pkt_desc __iomem *)(port->card->rambase +
99 				    desc_offset(port, desc, transmit));
100 }
101 
102 
103 static inline u32 buffer_offset(port_t *port, u16 desc, int transmit)
104 {
105 	return port->card->buff_offset +
106 		desc_abs_number(port, desc, transmit) * (u32)HDLC_MAX_MRU;
107 }
108 
109 
110 static inline void sca_set_carrier(port_t *port)
111 {
112 	if (!(sca_in(get_msci(port) + ST3, port->card) & ST3_DCD)) {
113 #ifdef DEBUG_LINK
114 		printk(KERN_DEBUG "%s: sca_set_carrier on\n",
115 		       port->netdev.name);
116 #endif
117 		netif_carrier_on(port->netdev);
118 	} else {
119 #ifdef DEBUG_LINK
120 		printk(KERN_DEBUG "%s: sca_set_carrier off\n",
121 		       port->netdev.name);
122 #endif
123 		netif_carrier_off(port->netdev);
124 	}
125 }
126 
127 
128 static void sca_init_port(port_t *port)
129 {
130 	card_t *card = port->card;
131 	u16 dmac_rx = get_dmac_rx(port), dmac_tx = get_dmac_tx(port);
132 	int transmit, i;
133 
134 	port->rxin = 0;
135 	port->txin = 0;
136 	port->txlast = 0;
137 
138 	for (transmit = 0; transmit < 2; transmit++) {
139 		u16 buffs = transmit ? card->tx_ring_buffers
140 			: card->rx_ring_buffers;
141 
142 		for (i = 0; i < buffs; i++) {
143 			pkt_desc __iomem *desc = desc_address(port, i, transmit);
144 			u16 chain_off = desc_offset(port, i + 1, transmit);
145 			u32 buff_off = buffer_offset(port, i, transmit);
146 
147 			writel(chain_off, &desc->cp);
148 			writel(buff_off, &desc->bp);
149 			writew(0, &desc->len);
150 			writeb(0, &desc->stat);
151 		}
152 	}
153 
154 	/* DMA disable - to halt state */
155 	sca_out(0, DSR_RX(port->chan), card);
156 	sca_out(0, DSR_TX(port->chan), card);
157 
158 	/* software ABORT - to initial state */
159 	sca_out(DCR_ABORT, DCR_RX(port->chan), card);
160 	sca_out(DCR_ABORT, DCR_TX(port->chan), card);
161 
162 	/* current desc addr */
163 	sca_outl(desc_offset(port, 0, 0), dmac_rx + CDAL, card);
164 	sca_outl(desc_offset(port, card->tx_ring_buffers - 1, 0),
165 		 dmac_rx + EDAL, card);
166 	sca_outl(desc_offset(port, 0, 1), dmac_tx + CDAL, card);
167 	sca_outl(desc_offset(port, 0, 1), dmac_tx + EDAL, card);
168 
169 	/* clear frame end interrupt counter */
170 	sca_out(DCR_CLEAR_EOF, DCR_RX(port->chan), card);
171 	sca_out(DCR_CLEAR_EOF, DCR_TX(port->chan), card);
172 
173 	/* Receive */
174 	sca_outw(HDLC_MAX_MRU, dmac_rx + BFLL, card); /* set buffer length */
175 	sca_out(0x14, DMR_RX(port->chan), card); /* Chain mode, Multi-frame */
176 	sca_out(DIR_EOME, DIR_RX(port->chan), card); /* enable interrupts */
177 	sca_out(DSR_DE, DSR_RX(port->chan), card); /* DMA enable */
178 
179 	/* Transmit */
180 	sca_out(0x14, DMR_TX(port->chan), card); /* Chain mode, Multi-frame */
181 	sca_out(DIR_EOME, DIR_TX(port->chan), card); /* enable interrupts */
182 
183 	sca_set_carrier(port);
184 	netif_napi_add(port->netdev, &port->napi, sca_poll, NAPI_WEIGHT);
185 }
186 
187 
188 /* MSCI interrupt service */
189 static inline void sca_msci_intr(port_t *port)
190 {
191 	u16 msci = get_msci(port);
192 	card_t* card = port->card;
193 
194 	if (sca_in(msci + ST1, card) & ST1_CDCD) {
195 		/* Reset MSCI CDCD status bit */
196 		sca_out(ST1_CDCD, msci + ST1, card);
197 		sca_set_carrier(port);
198 	}
199 }
200 
201 
202 static inline void sca_rx(card_t *card, port_t *port, pkt_desc __iomem *desc,
203 			  u16 rxin)
204 {
205 	struct net_device *dev = port->netdev;
206 	struct sk_buff *skb;
207 	u16 len;
208 	u32 buff;
209 
210 	len = readw(&desc->len);
211 	skb = dev_alloc_skb(len);
212 	if (!skb) {
213 		dev->stats.rx_dropped++;
214 		return;
215 	}
216 
217 	buff = buffer_offset(port, rxin, 0);
218 	memcpy_fromio(skb->data, card->rambase + buff, len);
219 
220 	skb_put(skb, len);
221 #ifdef DEBUG_PKT
222 	printk(KERN_DEBUG "%s RX(%i):", dev->name, skb->len);
223 	debug_frame(skb);
224 #endif
225 	dev->stats.rx_packets++;
226 	dev->stats.rx_bytes += skb->len;
227 	skb->protocol = hdlc_type_trans(skb, dev);
228 	netif_receive_skb(skb);
229 }
230 
231 
232 /* Receive DMA service */
233 static inline int sca_rx_done(port_t *port, int budget)
234 {
235 	struct net_device *dev = port->netdev;
236 	u16 dmac = get_dmac_rx(port);
237 	card_t *card = port->card;
238 	u8 stat = sca_in(DSR_RX(port->chan), card); /* read DMA Status */
239 	int received = 0;
240 
241 	/* Reset DSR status bits */
242 	sca_out((stat & (DSR_EOT | DSR_EOM | DSR_BOF | DSR_COF)) | DSR_DWE,
243 		DSR_RX(port->chan), card);
244 
245 	if (stat & DSR_BOF)
246 		/* Dropped one or more frames */
247 		dev->stats.rx_over_errors++;
248 
249 	while (received < budget) {
250 		u32 desc_off = desc_offset(port, port->rxin, 0);
251 		pkt_desc __iomem *desc;
252 		u32 cda = sca_inl(dmac + CDAL, card);
253 
254 		if ((cda >= desc_off) && (cda < desc_off + sizeof(pkt_desc)))
255 			break;	/* No frame received */
256 
257 		desc = desc_address(port, port->rxin, 0);
258 		stat = readb(&desc->stat);
259 		if (!(stat & ST_RX_EOM))
260 			port->rxpart = 1; /* partial frame received */
261 		else if ((stat & ST_ERROR_MASK) || port->rxpart) {
262 			dev->stats.rx_errors++;
263 			if (stat & ST_RX_OVERRUN)
264 				dev->stats.rx_fifo_errors++;
265 			else if ((stat & (ST_RX_SHORT | ST_RX_ABORT |
266 					  ST_RX_RESBIT)) || port->rxpart)
267 				dev->stats.rx_frame_errors++;
268 			else if (stat & ST_RX_CRC)
269 				dev->stats.rx_crc_errors++;
270 			if (stat & ST_RX_EOM)
271 				port->rxpart = 0; /* received last fragment */
272 		} else {
273 			sca_rx(card, port, desc, port->rxin);
274 			received++;
275 		}
276 
277 		/* Set new error descriptor address */
278 		sca_outl(desc_off, dmac + EDAL, card);
279 		port->rxin = (port->rxin + 1) % card->rx_ring_buffers;
280 	}
281 
282 	/* make sure RX DMA is enabled */
283 	sca_out(DSR_DE, DSR_RX(port->chan), card);
284 	return received;
285 }
286 
287 
288 /* Transmit DMA service */
289 static inline void sca_tx_done(port_t *port)
290 {
291 	struct net_device *dev = port->netdev;
292 	card_t* card = port->card;
293 	u8 stat;
294 	unsigned count = 0;
295 
296 	spin_lock(&port->lock);
297 
298 	stat = sca_in(DSR_TX(port->chan), card); /* read DMA Status */
299 
300 	/* Reset DSR status bits */
301 	sca_out((stat & (DSR_EOT | DSR_EOM | DSR_BOF | DSR_COF)) | DSR_DWE,
302 		DSR_TX(port->chan), card);
303 
304 	while (1) {
305 		pkt_desc __iomem *desc = desc_address(port, port->txlast, 1);
306 		u8 stat = readb(&desc->stat);
307 
308 		if (!(stat & ST_TX_OWNRSHP))
309 			break; /* not yet transmitted */
310 		if (stat & ST_TX_UNDRRUN) {
311 			dev->stats.tx_errors++;
312 			dev->stats.tx_fifo_errors++;
313 		} else {
314 			dev->stats.tx_packets++;
315 			dev->stats.tx_bytes += readw(&desc->len);
316 		}
317 		writeb(0, &desc->stat);	/* Free descriptor */
318 		count++;
319 		port->txlast = (port->txlast + 1) % card->tx_ring_buffers;
320 	}
321 
322 	if (count)
323 		netif_wake_queue(dev);
324 	spin_unlock(&port->lock);
325 }
326 
327 
328 static int sca_poll(struct napi_struct *napi, int budget)
329 {
330 	port_t *port = container_of(napi, port_t, napi);
331 	u32 isr0 = sca_inl(ISR0, port->card);
332 	int received = 0;
333 
334 	if (isr0 & (port->chan ? 0x08000000 : 0x00080000))
335 		sca_msci_intr(port);
336 
337 	if (isr0 & (port->chan ? 0x00002000 : 0x00000020))
338 		sca_tx_done(port);
339 
340 	if (isr0 & (port->chan ? 0x00000200 : 0x00000002))
341 		received = sca_rx_done(port, budget);
342 
343 	if (received < budget) {
344 		napi_complete(napi);
345 		enable_intr(port);
346 	}
347 
348 	return received;
349 }
350 
351 static irqreturn_t sca_intr(int irq, void *dev_id)
352 {
353 	card_t *card = dev_id;
354 	u32 isr0 = sca_inl(ISR0, card);
355 	int i, handled = 0;
356 
357 	for (i = 0; i < 2; i++) {
358 		port_t *port = get_port(card, i);
359 		if (port && (isr0 & (i ? 0x08002200 : 0x00080022))) {
360 			handled = 1;
361 			disable_intr(port);
362 			napi_schedule(&port->napi);
363 		}
364 	}
365 
366 	return IRQ_RETVAL(handled);
367 }
368 
369 
370 static void sca_set_port(port_t *port)
371 {
372 	card_t* card = port->card;
373 	u16 msci = get_msci(port);
374 	u8 md2 = sca_in(msci + MD2, card);
375 	unsigned int tmc, br = 10, brv = 1024;
376 
377 
378 	if (port->settings.clock_rate > 0) {
379 		/* Try lower br for better accuracy*/
380 		do {
381 			br--;
382 			brv >>= 1; /* brv = 2^9 = 512 max in specs */
383 
384 			/* Baud Rate = CLOCK_BASE / TMC / 2^BR */
385 			tmc = CLOCK_BASE / brv / port->settings.clock_rate;
386 		}while (br > 1 && tmc <= 128);
387 
388 		if (tmc < 1) {
389 			tmc = 1;
390 			br = 0;	/* For baud=CLOCK_BASE we use tmc=1 br=0 */
391 			brv = 1;
392 		} else if (tmc > 255)
393 			tmc = 256; /* tmc=0 means 256 - low baud rates */
394 
395 		port->settings.clock_rate = CLOCK_BASE / brv / tmc;
396 	} else {
397 		br = 9; /* Minimum clock rate */
398 		tmc = 256;	/* 8bit = 0 */
399 		port->settings.clock_rate = CLOCK_BASE / (256 * 512);
400 	}
401 
402 	port->rxs = (port->rxs & ~CLK_BRG_MASK) | br;
403 	port->txs = (port->txs & ~CLK_BRG_MASK) | br;
404 	port->tmc = tmc;
405 
406 	/* baud divisor - time constant*/
407 	sca_out(port->tmc, msci + TMCR, card);
408 	sca_out(port->tmc, msci + TMCT, card);
409 
410 	/* Set BRG bits */
411 	sca_out(port->rxs, msci + RXS, card);
412 	sca_out(port->txs, msci + TXS, card);
413 
414 	if (port->settings.loopback)
415 		md2 |= MD2_LOOPBACK;
416 	else
417 		md2 &= ~MD2_LOOPBACK;
418 
419 	sca_out(md2, msci + MD2, card);
420 
421 }
422 
423 
424 static void sca_open(struct net_device *dev)
425 {
426 	port_t *port = dev_to_port(dev);
427 	card_t* card = port->card;
428 	u16 msci = get_msci(port);
429 	u8 md0, md2;
430 
431 	switch(port->encoding) {
432 	case ENCODING_NRZ:	md2 = MD2_NRZ;		break;
433 	case ENCODING_NRZI:	md2 = MD2_NRZI;		break;
434 	case ENCODING_FM_MARK:	md2 = MD2_FM_MARK;	break;
435 	case ENCODING_FM_SPACE:	md2 = MD2_FM_SPACE;	break;
436 	default:		md2 = MD2_MANCHESTER;
437 	}
438 
439 	if (port->settings.loopback)
440 		md2 |= MD2_LOOPBACK;
441 
442 	switch(port->parity) {
443 	case PARITY_CRC16_PR0:	     md0 = MD0_HDLC | MD0_CRC_16_0;  break;
444 	case PARITY_CRC16_PR1:	     md0 = MD0_HDLC | MD0_CRC_16;    break;
445 	case PARITY_CRC32_PR1_CCITT: md0 = MD0_HDLC | MD0_CRC_ITU32; break;
446 	case PARITY_CRC16_PR1_CCITT: md0 = MD0_HDLC | MD0_CRC_ITU;   break;
447 	default:		     md0 = MD0_HDLC | MD0_CRC_NONE;
448 	}
449 
450 	sca_out(CMD_RESET, msci + CMD, card);
451 	sca_out(md0, msci + MD0, card);
452 	sca_out(0x00, msci + MD1, card); /* no address field check */
453 	sca_out(md2, msci + MD2, card);
454 	sca_out(0x7E, msci + IDL, card); /* flag character 0x7E */
455 	/* Skip the rest of underrun frame */
456 	sca_out(CTL_IDLE | CTL_URCT | CTL_URSKP, msci + CTL, card);
457 	sca_out(0x0F, msci + RNR, card); /* +1=RX DMA activation condition */
458 	sca_out(0x3C, msci + TFS, card); /* +1 = TX start */
459 	sca_out(0x38, msci + TCR, card); /* =Critical TX DMA activ condition */
460 	sca_out(0x38, msci + TNR0, card); /* =TX DMA activation condition */
461 	sca_out(0x3F, msci + TNR1, card); /* +1=TX DMA deactivation condition*/
462 
463 /* We're using the following interrupts:
464    - RXINTA (DCD changes only)
465    - DMIB (EOM - single frame transfer complete)
466 */
467 	sca_outl(IE0_RXINTA | IE0_CDCD, msci + IE0, card);
468 
469 	sca_out(port->tmc, msci + TMCR, card);
470 	sca_out(port->tmc, msci + TMCT, card);
471 	sca_out(port->rxs, msci + RXS, card);
472 	sca_out(port->txs, msci + TXS, card);
473 	sca_out(CMD_TX_ENABLE, msci + CMD, card);
474 	sca_out(CMD_RX_ENABLE, msci + CMD, card);
475 
476 	sca_set_carrier(port);
477 	enable_intr(port);
478 	napi_enable(&port->napi);
479 	netif_start_queue(dev);
480 }
481 
482 
483 static void sca_close(struct net_device *dev)
484 {
485 	port_t *port = dev_to_port(dev);
486 
487 	/* reset channel */
488 	sca_out(CMD_RESET, get_msci(port) + CMD, port->card);
489 	disable_intr(port);
490 	napi_disable(&port->napi);
491 	netif_stop_queue(dev);
492 }
493 
494 
495 static int sca_attach(struct net_device *dev, unsigned short encoding,
496 		      unsigned short parity)
497 {
498 	if (encoding != ENCODING_NRZ &&
499 	    encoding != ENCODING_NRZI &&
500 	    encoding != ENCODING_FM_MARK &&
501 	    encoding != ENCODING_FM_SPACE &&
502 	    encoding != ENCODING_MANCHESTER)
503 		return -EINVAL;
504 
505 	if (parity != PARITY_NONE &&
506 	    parity != PARITY_CRC16_PR0 &&
507 	    parity != PARITY_CRC16_PR1 &&
508 	    parity != PARITY_CRC32_PR1_CCITT &&
509 	    parity != PARITY_CRC16_PR1_CCITT)
510 		return -EINVAL;
511 
512 	dev_to_port(dev)->encoding = encoding;
513 	dev_to_port(dev)->parity = parity;
514 	return 0;
515 }
516 
517 
518 #ifdef DEBUG_RINGS
519 static void sca_dump_rings(struct net_device *dev)
520 {
521 	port_t *port = dev_to_port(dev);
522 	card_t *card = port->card;
523 	u16 cnt;
524 
525 	printk(KERN_DEBUG "RX ring: CDA=%u EDA=%u DSR=%02X in=%u %sactive",
526 	       sca_inl(get_dmac_rx(port) + CDAL, card),
527 	       sca_inl(get_dmac_rx(port) + EDAL, card),
528 	       sca_in(DSR_RX(port->chan), card), port->rxin,
529 	       sca_in(DSR_RX(port->chan), card) & DSR_DE ? "" : "in");
530 	for (cnt = 0; cnt < port->card->rx_ring_buffers; cnt++)
531 		pr_cont(" %02X", readb(&(desc_address(port, cnt, 0)->stat)));
532 	pr_cont("\n");
533 
534 	printk(KERN_DEBUG "TX ring: CDA=%u EDA=%u DSR=%02X in=%u "
535 	       "last=%u %sactive",
536 	       sca_inl(get_dmac_tx(port) + CDAL, card),
537 	       sca_inl(get_dmac_tx(port) + EDAL, card),
538 	       sca_in(DSR_TX(port->chan), card), port->txin, port->txlast,
539 	       sca_in(DSR_TX(port->chan), card) & DSR_DE ? "" : "in");
540 
541 	for (cnt = 0; cnt < port->card->tx_ring_buffers; cnt++)
542 		pr_cont(" %02X", readb(&(desc_address(port, cnt, 1)->stat)));
543 	pr_cont("\n");
544 
545 	printk(KERN_DEBUG "MSCI: MD: %02x %02x %02x,"
546 	       " ST: %02x %02x %02x %02x %02x, FST: %02x CST: %02x %02x\n",
547 	       sca_in(get_msci(port) + MD0, card),
548 	       sca_in(get_msci(port) + MD1, card),
549 	       sca_in(get_msci(port) + MD2, card),
550 	       sca_in(get_msci(port) + ST0, card),
551 	       sca_in(get_msci(port) + ST1, card),
552 	       sca_in(get_msci(port) + ST2, card),
553 	       sca_in(get_msci(port) + ST3, card),
554 	       sca_in(get_msci(port) + ST4, card),
555 	       sca_in(get_msci(port) + FST, card),
556 	       sca_in(get_msci(port) + CST0, card),
557 	       sca_in(get_msci(port) + CST1, card));
558 
559 	printk(KERN_DEBUG "ILAR: %02x ISR: %08x %08x\n", sca_in(ILAR, card),
560 	       sca_inl(ISR0, card), sca_inl(ISR1, card));
561 }
562 #endif /* DEBUG_RINGS */
563 
564 
565 static netdev_tx_t sca_xmit(struct sk_buff *skb, struct net_device *dev)
566 {
567 	port_t *port = dev_to_port(dev);
568 	card_t *card = port->card;
569 	pkt_desc __iomem *desc;
570 	u32 buff, len;
571 
572 	spin_lock_irq(&port->lock);
573 
574 	desc = desc_address(port, port->txin + 1, 1);
575 	BUG_ON(readb(&desc->stat)); /* previous xmit should stop queue */
576 
577 #ifdef DEBUG_PKT
578 	printk(KERN_DEBUG "%s TX(%i):", dev->name, skb->len);
579 	debug_frame(skb);
580 #endif
581 
582 	desc = desc_address(port, port->txin, 1);
583 	buff = buffer_offset(port, port->txin, 1);
584 	len = skb->len;
585 	memcpy_toio(card->rambase + buff, skb->data, len);
586 
587 	writew(len, &desc->len);
588 	writeb(ST_TX_EOM, &desc->stat);
589 
590 	port->txin = (port->txin + 1) % card->tx_ring_buffers;
591 	sca_outl(desc_offset(port, port->txin, 1),
592 		 get_dmac_tx(port) + EDAL, card);
593 
594 	sca_out(DSR_DE, DSR_TX(port->chan), card); /* Enable TX DMA */
595 
596 	desc = desc_address(port, port->txin + 1, 1);
597 	if (readb(&desc->stat)) /* allow 1 packet gap */
598 		netif_stop_queue(dev);
599 
600 	spin_unlock_irq(&port->lock);
601 
602 	dev_kfree_skb(skb);
603 	return NETDEV_TX_OK;
604 }
605 
606 
607 static u32 sca_detect_ram(card_t *card, u8 __iomem *rambase, u32 ramsize)
608 {
609 	/* Round RAM size to 32 bits, fill from end to start */
610 	u32 i = ramsize &= ~3;
611 
612 	do {
613 		i -= 4;
614 		writel(i ^ 0x12345678, rambase + i);
615 	} while (i > 0);
616 
617 	for (i = 0; i < ramsize ; i += 4) {
618 		if (readl(rambase + i) != (i ^ 0x12345678))
619 			break;
620 	}
621 
622 	return i;
623 }
624 
625 
626 static void sca_init(card_t *card, int wait_states)
627 {
628 	sca_out(wait_states, WCRL, card); /* Wait Control */
629 	sca_out(wait_states, WCRM, card);
630 	sca_out(wait_states, WCRH, card);
631 
632 	sca_out(0, DMER, card);	/* DMA Master disable */
633 	sca_out(0x03, PCR, card); /* DMA priority */
634 	sca_out(0, DSR_RX(0), card); /* DMA disable - to halt state */
635 	sca_out(0, DSR_TX(0), card);
636 	sca_out(0, DSR_RX(1), card);
637 	sca_out(0, DSR_TX(1), card);
638 	sca_out(DMER_DME, DMER, card); /* DMA Master enable */
639 }
640