xref: /openbmc/linux/drivers/net/wan/hd64572.c (revision 63dc02bd)
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/uaccess.h>
44 #include "hd64572.h"
45 
46 #define NAPI_WEIGHT		16
47 
48 #define get_msci(port)	  (port->chan ?   MSCI1_OFFSET :   MSCI0_OFFSET)
49 #define get_dmac_rx(port) (port->chan ? DMAC1RX_OFFSET : DMAC0RX_OFFSET)
50 #define get_dmac_tx(port) (port->chan ? DMAC1TX_OFFSET : DMAC0TX_OFFSET)
51 
52 #define sca_in(reg, card)	     readb(card->scabase + (reg))
53 #define sca_out(value, reg, card)    writeb(value, card->scabase + (reg))
54 #define sca_inw(reg, card)	     readw(card->scabase + (reg))
55 #define sca_outw(value, reg, card)   writew(value, card->scabase + (reg))
56 #define sca_inl(reg, card)	     readl(card->scabase + (reg))
57 #define sca_outl(value, reg, card)   writel(value, card->scabase + (reg))
58 
59 static int sca_poll(struct napi_struct *napi, int budget);
60 
61 static inline port_t* dev_to_port(struct net_device *dev)
62 {
63 	return dev_to_hdlc(dev)->priv;
64 }
65 
66 static inline void enable_intr(port_t *port)
67 {
68 	/* enable DMIB and MSCI RXINTA interrupts */
69 	sca_outl(sca_inl(IER0, port->card) |
70 		 (port->chan ? 0x08002200 : 0x00080022), IER0, port->card);
71 }
72 
73 static inline void disable_intr(port_t *port)
74 {
75 	sca_outl(sca_inl(IER0, port->card) &
76 		 (port->chan ? 0x00FF00FF : 0xFF00FF00), IER0, port->card);
77 }
78 
79 static inline u16 desc_abs_number(port_t *port, u16 desc, int transmit)
80 {
81 	u16 rx_buffs = port->card->rx_ring_buffers;
82 	u16 tx_buffs = port->card->tx_ring_buffers;
83 
84 	desc %= (transmit ? tx_buffs : rx_buffs); // called with "X + 1" etc.
85 	return port->chan * (rx_buffs + tx_buffs) + transmit * rx_buffs + desc;
86 }
87 
88 
89 static inline u16 desc_offset(port_t *port, u16 desc, int transmit)
90 {
91 	/* Descriptor offset always fits in 16 bits */
92 	return desc_abs_number(port, desc, transmit) * sizeof(pkt_desc);
93 }
94 
95 
96 static inline pkt_desc __iomem *desc_address(port_t *port, u16 desc,
97 					     int transmit)
98 {
99 	return (pkt_desc __iomem *)(port->card->rambase +
100 				    desc_offset(port, desc, transmit));
101 }
102 
103 
104 static inline u32 buffer_offset(port_t *port, u16 desc, int transmit)
105 {
106 	return port->card->buff_offset +
107 		desc_abs_number(port, desc, transmit) * (u32)HDLC_MAX_MRU;
108 }
109 
110 
111 static inline void sca_set_carrier(port_t *port)
112 {
113 	if (!(sca_in(get_msci(port) + ST3, port->card) & ST3_DCD)) {
114 #ifdef DEBUG_LINK
115 		printk(KERN_DEBUG "%s: sca_set_carrier on\n",
116 		       port->netdev.name);
117 #endif
118 		netif_carrier_on(port->netdev);
119 	} else {
120 #ifdef DEBUG_LINK
121 		printk(KERN_DEBUG "%s: sca_set_carrier off\n",
122 		       port->netdev.name);
123 #endif
124 		netif_carrier_off(port->netdev);
125 	}
126 }
127 
128 
129 static void sca_init_port(port_t *port)
130 {
131 	card_t *card = port->card;
132 	u16 dmac_rx = get_dmac_rx(port), dmac_tx = get_dmac_tx(port);
133 	int transmit, i;
134 
135 	port->rxin = 0;
136 	port->txin = 0;
137 	port->txlast = 0;
138 
139 	for (transmit = 0; transmit < 2; transmit++) {
140 		u16 buffs = transmit ? card->tx_ring_buffers
141 			: card->rx_ring_buffers;
142 
143 		for (i = 0; i < buffs; i++) {
144 			pkt_desc __iomem *desc = desc_address(port, i, transmit);
145 			u16 chain_off = desc_offset(port, i + 1, transmit);
146 			u32 buff_off = buffer_offset(port, i, transmit);
147 
148 			writel(chain_off, &desc->cp);
149 			writel(buff_off, &desc->bp);
150 			writew(0, &desc->len);
151 			writeb(0, &desc->stat);
152 		}
153 	}
154 
155 	/* DMA disable - to halt state */
156 	sca_out(0, DSR_RX(port->chan), card);
157 	sca_out(0, DSR_TX(port->chan), card);
158 
159 	/* software ABORT - to initial state */
160 	sca_out(DCR_ABORT, DCR_RX(port->chan), card);
161 	sca_out(DCR_ABORT, DCR_TX(port->chan), card);
162 
163 	/* current desc addr */
164 	sca_outl(desc_offset(port, 0, 0), dmac_rx + CDAL, card);
165 	sca_outl(desc_offset(port, card->tx_ring_buffers - 1, 0),
166 		 dmac_rx + EDAL, card);
167 	sca_outl(desc_offset(port, 0, 1), dmac_tx + CDAL, card);
168 	sca_outl(desc_offset(port, 0, 1), dmac_tx + EDAL, card);
169 
170 	/* clear frame end interrupt counter */
171 	sca_out(DCR_CLEAR_EOF, DCR_RX(port->chan), card);
172 	sca_out(DCR_CLEAR_EOF, DCR_TX(port->chan), card);
173 
174 	/* Receive */
175 	sca_outw(HDLC_MAX_MRU, dmac_rx + BFLL, card); /* set buffer length */
176 	sca_out(0x14, DMR_RX(port->chan), card); /* Chain mode, Multi-frame */
177 	sca_out(DIR_EOME, DIR_RX(port->chan), card); /* enable interrupts */
178 	sca_out(DSR_DE, DSR_RX(port->chan), card); /* DMA enable */
179 
180 	/* Transmit */
181 	sca_out(0x14, DMR_TX(port->chan), card); /* Chain mode, Multi-frame */
182 	sca_out(DIR_EOME, DIR_TX(port->chan), card); /* enable interrupts */
183 
184 	sca_set_carrier(port);
185 	netif_napi_add(port->netdev, &port->napi, sca_poll, NAPI_WEIGHT);
186 }
187 
188 
189 /* MSCI interrupt service */
190 static inline void sca_msci_intr(port_t *port)
191 {
192 	u16 msci = get_msci(port);
193 	card_t* card = port->card;
194 
195 	if (sca_in(msci + ST1, card) & ST1_CDCD) {
196 		/* Reset MSCI CDCD status bit */
197 		sca_out(ST1_CDCD, msci + ST1, card);
198 		sca_set_carrier(port);
199 	}
200 }
201 
202 
203 static inline void sca_rx(card_t *card, port_t *port, pkt_desc __iomem *desc,
204 			  u16 rxin)
205 {
206 	struct net_device *dev = port->netdev;
207 	struct sk_buff *skb;
208 	u16 len;
209 	u32 buff;
210 
211 	len = readw(&desc->len);
212 	skb = dev_alloc_skb(len);
213 	if (!skb) {
214 		dev->stats.rx_dropped++;
215 		return;
216 	}
217 
218 	buff = buffer_offset(port, rxin, 0);
219 	memcpy_fromio(skb->data, card->rambase + buff, len);
220 
221 	skb_put(skb, len);
222 #ifdef DEBUG_PKT
223 	printk(KERN_DEBUG "%s RX(%i):", dev->name, skb->len);
224 	debug_frame(skb);
225 #endif
226 	dev->stats.rx_packets++;
227 	dev->stats.rx_bytes += skb->len;
228 	skb->protocol = hdlc_type_trans(skb, dev);
229 	netif_receive_skb(skb);
230 }
231 
232 
233 /* Receive DMA service */
234 static inline int sca_rx_done(port_t *port, int budget)
235 {
236 	struct net_device *dev = port->netdev;
237 	u16 dmac = get_dmac_rx(port);
238 	card_t *card = port->card;
239 	u8 stat = sca_in(DSR_RX(port->chan), card); /* read DMA Status */
240 	int received = 0;
241 
242 	/* Reset DSR status bits */
243 	sca_out((stat & (DSR_EOT | DSR_EOM | DSR_BOF | DSR_COF)) | DSR_DWE,
244 		DSR_RX(port->chan), card);
245 
246 	if (stat & DSR_BOF)
247 		/* Dropped one or more frames */
248 		dev->stats.rx_over_errors++;
249 
250 	while (received < budget) {
251 		u32 desc_off = desc_offset(port, port->rxin, 0);
252 		pkt_desc __iomem *desc;
253 		u32 cda = sca_inl(dmac + CDAL, card);
254 
255 		if ((cda >= desc_off) && (cda < desc_off + sizeof(pkt_desc)))
256 			break;	/* No frame received */
257 
258 		desc = desc_address(port, port->rxin, 0);
259 		stat = readb(&desc->stat);
260 		if (!(stat & ST_RX_EOM))
261 			port->rxpart = 1; /* partial frame received */
262 		else if ((stat & ST_ERROR_MASK) || port->rxpart) {
263 			dev->stats.rx_errors++;
264 			if (stat & ST_RX_OVERRUN)
265 				dev->stats.rx_fifo_errors++;
266 			else if ((stat & (ST_RX_SHORT | ST_RX_ABORT |
267 					  ST_RX_RESBIT)) || port->rxpart)
268 				dev->stats.rx_frame_errors++;
269 			else if (stat & ST_RX_CRC)
270 				dev->stats.rx_crc_errors++;
271 			if (stat & ST_RX_EOM)
272 				port->rxpart = 0; /* received last fragment */
273 		} else {
274 			sca_rx(card, port, desc, port->rxin);
275 			received++;
276 		}
277 
278 		/* Set new error descriptor address */
279 		sca_outl(desc_off, dmac + EDAL, card);
280 		port->rxin = (port->rxin + 1) % card->rx_ring_buffers;
281 	}
282 
283 	/* make sure RX DMA is enabled */
284 	sca_out(DSR_DE, DSR_RX(port->chan), card);
285 	return received;
286 }
287 
288 
289 /* Transmit DMA service */
290 static inline void sca_tx_done(port_t *port)
291 {
292 	struct net_device *dev = port->netdev;
293 	card_t* card = port->card;
294 	u8 stat;
295 	unsigned count = 0;
296 
297 	spin_lock(&port->lock);
298 
299 	stat = sca_in(DSR_TX(port->chan), card); /* read DMA Status */
300 
301 	/* Reset DSR status bits */
302 	sca_out((stat & (DSR_EOT | DSR_EOM | DSR_BOF | DSR_COF)) | DSR_DWE,
303 		DSR_TX(port->chan), card);
304 
305 	while (1) {
306 		pkt_desc __iomem *desc = desc_address(port, port->txlast, 1);
307 		u8 stat = readb(&desc->stat);
308 
309 		if (!(stat & ST_TX_OWNRSHP))
310 			break; /* not yet transmitted */
311 		if (stat & ST_TX_UNDRRUN) {
312 			dev->stats.tx_errors++;
313 			dev->stats.tx_fifo_errors++;
314 		} else {
315 			dev->stats.tx_packets++;
316 			dev->stats.tx_bytes += readw(&desc->len);
317 		}
318 		writeb(0, &desc->stat);	/* Free descriptor */
319 		count++;
320 		port->txlast = (port->txlast + 1) % card->tx_ring_buffers;
321 	}
322 
323 	if (count)
324 		netif_wake_queue(dev);
325 	spin_unlock(&port->lock);
326 }
327 
328 
329 static int sca_poll(struct napi_struct *napi, int budget)
330 {
331 	port_t *port = container_of(napi, port_t, napi);
332 	u32 isr0 = sca_inl(ISR0, port->card);
333 	int received = 0;
334 
335 	if (isr0 & (port->chan ? 0x08000000 : 0x00080000))
336 		sca_msci_intr(port);
337 
338 	if (isr0 & (port->chan ? 0x00002000 : 0x00000020))
339 		sca_tx_done(port);
340 
341 	if (isr0 & (port->chan ? 0x00000200 : 0x00000002))
342 		received = sca_rx_done(port, budget);
343 
344 	if (received < budget) {
345 		napi_complete(napi);
346 		enable_intr(port);
347 	}
348 
349 	return received;
350 }
351 
352 static irqreturn_t sca_intr(int irq, void *dev_id)
353 {
354 	card_t *card = dev_id;
355 	u32 isr0 = sca_inl(ISR0, card);
356 	int i, handled = 0;
357 
358 	for (i = 0; i < 2; i++) {
359 		port_t *port = get_port(card, i);
360 		if (port && (isr0 & (i ? 0x08002200 : 0x00080022))) {
361 			handled = 1;
362 			disable_intr(port);
363 			napi_schedule(&port->napi);
364 		}
365 	}
366 
367 	return IRQ_RETVAL(handled);
368 }
369 
370 
371 static void sca_set_port(port_t *port)
372 {
373 	card_t* card = port->card;
374 	u16 msci = get_msci(port);
375 	u8 md2 = sca_in(msci + MD2, card);
376 	unsigned int tmc, br = 10, brv = 1024;
377 
378 
379 	if (port->settings.clock_rate > 0) {
380 		/* Try lower br for better accuracy*/
381 		do {
382 			br--;
383 			brv >>= 1; /* brv = 2^9 = 512 max in specs */
384 
385 			/* Baud Rate = CLOCK_BASE / TMC / 2^BR */
386 			tmc = CLOCK_BASE / brv / port->settings.clock_rate;
387 		}while (br > 1 && tmc <= 128);
388 
389 		if (tmc < 1) {
390 			tmc = 1;
391 			br = 0;	/* For baud=CLOCK_BASE we use tmc=1 br=0 */
392 			brv = 1;
393 		} else if (tmc > 255)
394 			tmc = 256; /* tmc=0 means 256 - low baud rates */
395 
396 		port->settings.clock_rate = CLOCK_BASE / brv / tmc;
397 	} else {
398 		br = 9; /* Minimum clock rate */
399 		tmc = 256;	/* 8bit = 0 */
400 		port->settings.clock_rate = CLOCK_BASE / (256 * 512);
401 	}
402 
403 	port->rxs = (port->rxs & ~CLK_BRG_MASK) | br;
404 	port->txs = (port->txs & ~CLK_BRG_MASK) | br;
405 	port->tmc = tmc;
406 
407 	/* baud divisor - time constant*/
408 	sca_out(port->tmc, msci + TMCR, card);
409 	sca_out(port->tmc, msci + TMCT, card);
410 
411 	/* Set BRG bits */
412 	sca_out(port->rxs, msci + RXS, card);
413 	sca_out(port->txs, msci + TXS, card);
414 
415 	if (port->settings.loopback)
416 		md2 |= MD2_LOOPBACK;
417 	else
418 		md2 &= ~MD2_LOOPBACK;
419 
420 	sca_out(md2, msci + MD2, card);
421 
422 }
423 
424 
425 static void sca_open(struct net_device *dev)
426 {
427 	port_t *port = dev_to_port(dev);
428 	card_t* card = port->card;
429 	u16 msci = get_msci(port);
430 	u8 md0, md2;
431 
432 	switch(port->encoding) {
433 	case ENCODING_NRZ:	md2 = MD2_NRZ;		break;
434 	case ENCODING_NRZI:	md2 = MD2_NRZI;		break;
435 	case ENCODING_FM_MARK:	md2 = MD2_FM_MARK;	break;
436 	case ENCODING_FM_SPACE:	md2 = MD2_FM_SPACE;	break;
437 	default:		md2 = MD2_MANCHESTER;
438 	}
439 
440 	if (port->settings.loopback)
441 		md2 |= MD2_LOOPBACK;
442 
443 	switch(port->parity) {
444 	case PARITY_CRC16_PR0:	     md0 = MD0_HDLC | MD0_CRC_16_0;  break;
445 	case PARITY_CRC16_PR1:	     md0 = MD0_HDLC | MD0_CRC_16;    break;
446 	case PARITY_CRC32_PR1_CCITT: md0 = MD0_HDLC | MD0_CRC_ITU32; break;
447 	case PARITY_CRC16_PR1_CCITT: md0 = MD0_HDLC | MD0_CRC_ITU;   break;
448 	default:		     md0 = MD0_HDLC | MD0_CRC_NONE;
449 	}
450 
451 	sca_out(CMD_RESET, msci + CMD, card);
452 	sca_out(md0, msci + MD0, card);
453 	sca_out(0x00, msci + MD1, card); /* no address field check */
454 	sca_out(md2, msci + MD2, card);
455 	sca_out(0x7E, msci + IDL, card); /* flag character 0x7E */
456 	/* Skip the rest of underrun frame */
457 	sca_out(CTL_IDLE | CTL_URCT | CTL_URSKP, msci + CTL, card);
458 	sca_out(0x0F, msci + RNR, card); /* +1=RX DMA activation condition */
459 	sca_out(0x3C, msci + TFS, card); /* +1 = TX start */
460 	sca_out(0x38, msci + TCR, card); /* =Critical TX DMA activ condition */
461 	sca_out(0x38, msci + TNR0, card); /* =TX DMA activation condition */
462 	sca_out(0x3F, msci + TNR1, card); /* +1=TX DMA deactivation condition*/
463 
464 /* We're using the following interrupts:
465    - RXINTA (DCD changes only)
466    - DMIB (EOM - single frame transfer complete)
467 */
468 	sca_outl(IE0_RXINTA | IE0_CDCD, msci + IE0, card);
469 
470 	sca_out(port->tmc, msci + TMCR, card);
471 	sca_out(port->tmc, msci + TMCT, card);
472 	sca_out(port->rxs, msci + RXS, card);
473 	sca_out(port->txs, msci + TXS, card);
474 	sca_out(CMD_TX_ENABLE, msci + CMD, card);
475 	sca_out(CMD_RX_ENABLE, msci + CMD, card);
476 
477 	sca_set_carrier(port);
478 	enable_intr(port);
479 	napi_enable(&port->napi);
480 	netif_start_queue(dev);
481 }
482 
483 
484 static void sca_close(struct net_device *dev)
485 {
486 	port_t *port = dev_to_port(dev);
487 
488 	/* reset channel */
489 	sca_out(CMD_RESET, get_msci(port) + CMD, port->card);
490 	disable_intr(port);
491 	napi_disable(&port->napi);
492 	netif_stop_queue(dev);
493 }
494 
495 
496 static int sca_attach(struct net_device *dev, unsigned short encoding,
497 		      unsigned short parity)
498 {
499 	if (encoding != ENCODING_NRZ &&
500 	    encoding != ENCODING_NRZI &&
501 	    encoding != ENCODING_FM_MARK &&
502 	    encoding != ENCODING_FM_SPACE &&
503 	    encoding != ENCODING_MANCHESTER)
504 		return -EINVAL;
505 
506 	if (parity != PARITY_NONE &&
507 	    parity != PARITY_CRC16_PR0 &&
508 	    parity != PARITY_CRC16_PR1 &&
509 	    parity != PARITY_CRC32_PR1_CCITT &&
510 	    parity != PARITY_CRC16_PR1_CCITT)
511 		return -EINVAL;
512 
513 	dev_to_port(dev)->encoding = encoding;
514 	dev_to_port(dev)->parity = parity;
515 	return 0;
516 }
517 
518 
519 #ifdef DEBUG_RINGS
520 static void sca_dump_rings(struct net_device *dev)
521 {
522 	port_t *port = dev_to_port(dev);
523 	card_t *card = port->card;
524 	u16 cnt;
525 
526 	printk(KERN_DEBUG "RX ring: CDA=%u EDA=%u DSR=%02X in=%u %sactive",
527 	       sca_inl(get_dmac_rx(port) + CDAL, card),
528 	       sca_inl(get_dmac_rx(port) + EDAL, card),
529 	       sca_in(DSR_RX(port->chan), card), port->rxin,
530 	       sca_in(DSR_RX(port->chan), card) & DSR_DE ? "" : "in");
531 	for (cnt = 0; cnt < port->card->rx_ring_buffers; cnt++)
532 		pr_cont(" %02X", readb(&(desc_address(port, cnt, 0)->stat)));
533 	pr_cont("\n");
534 
535 	printk(KERN_DEBUG "TX ring: CDA=%u EDA=%u DSR=%02X in=%u "
536 	       "last=%u %sactive",
537 	       sca_inl(get_dmac_tx(port) + CDAL, card),
538 	       sca_inl(get_dmac_tx(port) + EDAL, card),
539 	       sca_in(DSR_TX(port->chan), card), port->txin, port->txlast,
540 	       sca_in(DSR_TX(port->chan), card) & DSR_DE ? "" : "in");
541 
542 	for (cnt = 0; cnt < port->card->tx_ring_buffers; cnt++)
543 		pr_cont(" %02X", readb(&(desc_address(port, cnt, 1)->stat)));
544 	pr_cont("\n");
545 
546 	printk(KERN_DEBUG "MSCI: MD: %02x %02x %02x,"
547 	       " ST: %02x %02x %02x %02x %02x, FST: %02x CST: %02x %02x\n",
548 	       sca_in(get_msci(port) + MD0, card),
549 	       sca_in(get_msci(port) + MD1, card),
550 	       sca_in(get_msci(port) + MD2, card),
551 	       sca_in(get_msci(port) + ST0, card),
552 	       sca_in(get_msci(port) + ST1, card),
553 	       sca_in(get_msci(port) + ST2, card),
554 	       sca_in(get_msci(port) + ST3, card),
555 	       sca_in(get_msci(port) + ST4, card),
556 	       sca_in(get_msci(port) + FST, card),
557 	       sca_in(get_msci(port) + CST0, card),
558 	       sca_in(get_msci(port) + CST1, card));
559 
560 	printk(KERN_DEBUG "ILAR: %02x ISR: %08x %08x\n", sca_in(ILAR, card),
561 	       sca_inl(ISR0, card), sca_inl(ISR1, card));
562 }
563 #endif /* DEBUG_RINGS */
564 
565 
566 static netdev_tx_t sca_xmit(struct sk_buff *skb, struct net_device *dev)
567 {
568 	port_t *port = dev_to_port(dev);
569 	card_t *card = port->card;
570 	pkt_desc __iomem *desc;
571 	u32 buff, len;
572 
573 	spin_lock_irq(&port->lock);
574 
575 	desc = desc_address(port, port->txin + 1, 1);
576 	BUG_ON(readb(&desc->stat)); /* previous xmit should stop queue */
577 
578 #ifdef DEBUG_PKT
579 	printk(KERN_DEBUG "%s TX(%i):", dev->name, skb->len);
580 	debug_frame(skb);
581 #endif
582 
583 	desc = desc_address(port, port->txin, 1);
584 	buff = buffer_offset(port, port->txin, 1);
585 	len = skb->len;
586 	memcpy_toio(card->rambase + buff, skb->data, len);
587 
588 	writew(len, &desc->len);
589 	writeb(ST_TX_EOM, &desc->stat);
590 
591 	port->txin = (port->txin + 1) % card->tx_ring_buffers;
592 	sca_outl(desc_offset(port, port->txin, 1),
593 		 get_dmac_tx(port) + EDAL, card);
594 
595 	sca_out(DSR_DE, DSR_TX(port->chan), card); /* Enable TX DMA */
596 
597 	desc = desc_address(port, port->txin + 1, 1);
598 	if (readb(&desc->stat)) /* allow 1 packet gap */
599 		netif_stop_queue(dev);
600 
601 	spin_unlock_irq(&port->lock);
602 
603 	dev_kfree_skb(skb);
604 	return NETDEV_TX_OK;
605 }
606 
607 
608 static u32 __devinit sca_detect_ram(card_t *card, u8 __iomem *rambase,
609 				    u32 ramsize)
610 {
611 	/* Round RAM size to 32 bits, fill from end to start */
612 	u32 i = ramsize &= ~3;
613 
614 	do {
615 		i -= 4;
616 		writel(i ^ 0x12345678, rambase + i);
617 	} while (i > 0);
618 
619 	for (i = 0; i < ramsize ; i += 4) {
620 		if (readl(rambase + i) != (i ^ 0x12345678))
621 			break;
622 	}
623 
624 	return i;
625 }
626 
627 
628 static void __devinit sca_init(card_t *card, int wait_states)
629 {
630 	sca_out(wait_states, WCRL, card); /* Wait Control */
631 	sca_out(wait_states, WCRM, card);
632 	sca_out(wait_states, WCRH, card);
633 
634 	sca_out(0, DMER, card);	/* DMA Master disable */
635 	sca_out(0x03, PCR, card); /* DMA priority */
636 	sca_out(0, DSR_RX(0), card); /* DMA disable - to halt state */
637 	sca_out(0, DSR_TX(0), card);
638 	sca_out(0, DSR_RX(1), card);
639 	sca_out(0, DSR_TX(1), card);
640 	sca_out(DMER_DME, DMER, card); /* DMA Master enable */
641 }
642