xref: /openbmc/linux/drivers/net/wan/hd64572.c (revision 3ce311af)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Hitachi (now Renesas) SCA-II HD64572 driver for Linux
4  *
5  * Copyright (C) 1998-2008 Krzysztof Halasa <khc@pm.waw.pl>
6  *
7  * Source of information: HD64572 SCA-II User's Manual
8  *
9  * We use the following SCA memory map:
10  *
11  * Packet buffer descriptor rings - starting from card->rambase:
12  * rx_ring_buffers * sizeof(pkt_desc) = logical channel #0 RX ring
13  * tx_ring_buffers * sizeof(pkt_desc) = logical channel #0 TX ring
14  * rx_ring_buffers * sizeof(pkt_desc) = logical channel #1 RX ring (if used)
15  * tx_ring_buffers * sizeof(pkt_desc) = logical channel #1 TX ring (if used)
16  *
17  * Packet data buffers - starting from card->rambase + buff_offset:
18  * rx_ring_buffers * HDLC_MAX_MRU     = logical channel #0 RX buffers
19  * tx_ring_buffers * HDLC_MAX_MRU     = logical channel #0 TX buffers
20  * rx_ring_buffers * HDLC_MAX_MRU     = logical channel #0 RX buffers (if used)
21  * tx_ring_buffers * HDLC_MAX_MRU     = logical channel #0 TX buffers (if used)
22  */
23 
24 #include <linux/bitops.h>
25 #include <linux/errno.h>
26 #include <linux/fcntl.h>
27 #include <linux/hdlc.h>
28 #include <linux/in.h>
29 #include <linux/interrupt.h>
30 #include <linux/ioport.h>
31 #include <linux/jiffies.h>
32 #include <linux/kernel.h>
33 #include <linux/module.h>
34 #include <linux/netdevice.h>
35 #include <linux/skbuff.h>
36 #include <linux/string.h>
37 #include <linux/types.h>
38 #include <asm/io.h>
39 #include <linux/uaccess.h>
40 #include "hd64572.h"
41 
42 #define NAPI_WEIGHT		16
43 
44 #define get_msci(port)	  (port->chan ?   MSCI1_OFFSET :   MSCI0_OFFSET)
45 #define get_dmac_rx(port) (port->chan ? DMAC1RX_OFFSET : DMAC0RX_OFFSET)
46 #define get_dmac_tx(port) (port->chan ? DMAC1TX_OFFSET : DMAC0TX_OFFSET)
47 
48 #define sca_in(reg, card)	     readb(card->scabase + (reg))
49 #define sca_out(value, reg, card)    writeb(value, card->scabase + (reg))
50 #define sca_inw(reg, card)	     readw(card->scabase + (reg))
51 #define sca_outw(value, reg, card)   writew(value, card->scabase + (reg))
52 #define sca_inl(reg, card)	     readl(card->scabase + (reg))
53 #define sca_outl(value, reg, card)   writel(value, card->scabase + (reg))
54 
55 static int sca_poll(struct napi_struct *napi, int budget);
56 
57 static inline port_t* dev_to_port(struct net_device *dev)
58 {
59 	return dev_to_hdlc(dev)->priv;
60 }
61 
62 static inline void enable_intr(port_t *port)
63 {
64 	/* enable DMIB and MSCI RXINTA interrupts */
65 	sca_outl(sca_inl(IER0, port->card) |
66 		 (port->chan ? 0x08002200 : 0x00080022), IER0, port->card);
67 }
68 
69 static inline void disable_intr(port_t *port)
70 {
71 	sca_outl(sca_inl(IER0, port->card) &
72 		 (port->chan ? 0x00FF00FF : 0xFF00FF00), IER0, port->card);
73 }
74 
75 static inline u16 desc_abs_number(port_t *port, u16 desc, int transmit)
76 {
77 	u16 rx_buffs = port->card->rx_ring_buffers;
78 	u16 tx_buffs = port->card->tx_ring_buffers;
79 
80 	desc %= (transmit ? tx_buffs : rx_buffs); // called with "X + 1" etc.
81 	return port->chan * (rx_buffs + tx_buffs) + transmit * rx_buffs + desc;
82 }
83 
84 
85 static inline u16 desc_offset(port_t *port, u16 desc, int transmit)
86 {
87 	/* Descriptor offset always fits in 16 bits */
88 	return desc_abs_number(port, desc, transmit) * sizeof(pkt_desc);
89 }
90 
91 
92 static inline pkt_desc __iomem *desc_address(port_t *port, u16 desc,
93 					     int transmit)
94 {
95 	return (pkt_desc __iomem *)(port->card->rambase +
96 				    desc_offset(port, desc, transmit));
97 }
98 
99 
100 static inline u32 buffer_offset(port_t *port, u16 desc, int transmit)
101 {
102 	return port->card->buff_offset +
103 		desc_abs_number(port, desc, transmit) * (u32)HDLC_MAX_MRU;
104 }
105 
106 
107 static inline void sca_set_carrier(port_t *port)
108 {
109 	if (!(sca_in(get_msci(port) + ST3, port->card) & ST3_DCD)) {
110 #ifdef DEBUG_LINK
111 		printk(KERN_DEBUG "%s: sca_set_carrier on\n",
112 		       port->netdev.name);
113 #endif
114 		netif_carrier_on(port->netdev);
115 	} else {
116 #ifdef DEBUG_LINK
117 		printk(KERN_DEBUG "%s: sca_set_carrier off\n",
118 		       port->netdev.name);
119 #endif
120 		netif_carrier_off(port->netdev);
121 	}
122 }
123 
124 
125 static void sca_init_port(port_t *port)
126 {
127 	card_t *card = port->card;
128 	u16 dmac_rx = get_dmac_rx(port), dmac_tx = get_dmac_tx(port);
129 	int transmit, i;
130 
131 	port->rxin = 0;
132 	port->txin = 0;
133 	port->txlast = 0;
134 
135 	for (transmit = 0; transmit < 2; transmit++) {
136 		u16 buffs = transmit ? card->tx_ring_buffers
137 			: card->rx_ring_buffers;
138 
139 		for (i = 0; i < buffs; i++) {
140 			pkt_desc __iomem *desc = desc_address(port, i, transmit);
141 			u16 chain_off = desc_offset(port, i + 1, transmit);
142 			u32 buff_off = buffer_offset(port, i, transmit);
143 
144 			writel(chain_off, &desc->cp);
145 			writel(buff_off, &desc->bp);
146 			writew(0, &desc->len);
147 			writeb(0, &desc->stat);
148 		}
149 	}
150 
151 	/* DMA disable - to halt state */
152 	sca_out(0, DSR_RX(port->chan), card);
153 	sca_out(0, DSR_TX(port->chan), card);
154 
155 	/* software ABORT - to initial state */
156 	sca_out(DCR_ABORT, DCR_RX(port->chan), card);
157 	sca_out(DCR_ABORT, DCR_TX(port->chan), card);
158 
159 	/* current desc addr */
160 	sca_outl(desc_offset(port, 0, 0), dmac_rx + CDAL, card);
161 	sca_outl(desc_offset(port, card->tx_ring_buffers - 1, 0),
162 		 dmac_rx + EDAL, card);
163 	sca_outl(desc_offset(port, 0, 1), dmac_tx + CDAL, card);
164 	sca_outl(desc_offset(port, 0, 1), dmac_tx + EDAL, card);
165 
166 	/* clear frame end interrupt counter */
167 	sca_out(DCR_CLEAR_EOF, DCR_RX(port->chan), card);
168 	sca_out(DCR_CLEAR_EOF, DCR_TX(port->chan), card);
169 
170 	/* Receive */
171 	sca_outw(HDLC_MAX_MRU, dmac_rx + BFLL, card); /* set buffer length */
172 	sca_out(0x14, DMR_RX(port->chan), card); /* Chain mode, Multi-frame */
173 	sca_out(DIR_EOME, DIR_RX(port->chan), card); /* enable interrupts */
174 	sca_out(DSR_DE, DSR_RX(port->chan), card); /* DMA enable */
175 
176 	/* Transmit */
177 	sca_out(0x14, DMR_TX(port->chan), card); /* Chain mode, Multi-frame */
178 	sca_out(DIR_EOME, DIR_TX(port->chan), card); /* enable interrupts */
179 
180 	sca_set_carrier(port);
181 	netif_napi_add(port->netdev, &port->napi, sca_poll, NAPI_WEIGHT);
182 }
183 
184 
185 /* MSCI interrupt service */
186 static inline void sca_msci_intr(port_t *port)
187 {
188 	u16 msci = get_msci(port);
189 	card_t* card = port->card;
190 
191 	if (sca_in(msci + ST1, card) & ST1_CDCD) {
192 		/* Reset MSCI CDCD status bit */
193 		sca_out(ST1_CDCD, msci + ST1, card);
194 		sca_set_carrier(port);
195 	}
196 }
197 
198 
199 static inline void sca_rx(card_t *card, port_t *port, pkt_desc __iomem *desc,
200 			  u16 rxin)
201 {
202 	struct net_device *dev = port->netdev;
203 	struct sk_buff *skb;
204 	u16 len;
205 	u32 buff;
206 
207 	len = readw(&desc->len);
208 	skb = dev_alloc_skb(len);
209 	if (!skb) {
210 		dev->stats.rx_dropped++;
211 		return;
212 	}
213 
214 	buff = buffer_offset(port, rxin, 0);
215 	memcpy_fromio(skb->data, card->rambase + buff, len);
216 
217 	skb_put(skb, len);
218 #ifdef DEBUG_PKT
219 	printk(KERN_DEBUG "%s RX(%i):", dev->name, skb->len);
220 	debug_frame(skb);
221 #endif
222 	dev->stats.rx_packets++;
223 	dev->stats.rx_bytes += skb->len;
224 	skb->protocol = hdlc_type_trans(skb, dev);
225 	netif_receive_skb(skb);
226 }
227 
228 
229 /* Receive DMA service */
230 static inline int sca_rx_done(port_t *port, int budget)
231 {
232 	struct net_device *dev = port->netdev;
233 	u16 dmac = get_dmac_rx(port);
234 	card_t *card = port->card;
235 	u8 stat = sca_in(DSR_RX(port->chan), card); /* read DMA Status */
236 	int received = 0;
237 
238 	/* Reset DSR status bits */
239 	sca_out((stat & (DSR_EOT | DSR_EOM | DSR_BOF | DSR_COF)) | DSR_DWE,
240 		DSR_RX(port->chan), card);
241 
242 	if (stat & DSR_BOF)
243 		/* Dropped one or more frames */
244 		dev->stats.rx_over_errors++;
245 
246 	while (received < budget) {
247 		u32 desc_off = desc_offset(port, port->rxin, 0);
248 		pkt_desc __iomem *desc;
249 		u32 cda = sca_inl(dmac + CDAL, card);
250 
251 		if ((cda >= desc_off) && (cda < desc_off + sizeof(pkt_desc)))
252 			break;	/* No frame received */
253 
254 		desc = desc_address(port, port->rxin, 0);
255 		stat = readb(&desc->stat);
256 		if (!(stat & ST_RX_EOM))
257 			port->rxpart = 1; /* partial frame received */
258 		else if ((stat & ST_ERROR_MASK) || port->rxpart) {
259 			dev->stats.rx_errors++;
260 			if (stat & ST_RX_OVERRUN)
261 				dev->stats.rx_fifo_errors++;
262 			else if ((stat & (ST_RX_SHORT | ST_RX_ABORT |
263 					  ST_RX_RESBIT)) || port->rxpart)
264 				dev->stats.rx_frame_errors++;
265 			else if (stat & ST_RX_CRC)
266 				dev->stats.rx_crc_errors++;
267 			if (stat & ST_RX_EOM)
268 				port->rxpart = 0; /* received last fragment */
269 		} else {
270 			sca_rx(card, port, desc, port->rxin);
271 			received++;
272 		}
273 
274 		/* Set new error descriptor address */
275 		sca_outl(desc_off, dmac + EDAL, card);
276 		port->rxin = (port->rxin + 1) % card->rx_ring_buffers;
277 	}
278 
279 	/* make sure RX DMA is enabled */
280 	sca_out(DSR_DE, DSR_RX(port->chan), card);
281 	return received;
282 }
283 
284 
285 /* Transmit DMA service */
286 static inline void sca_tx_done(port_t *port)
287 {
288 	struct net_device *dev = port->netdev;
289 	card_t* card = port->card;
290 	u8 stat;
291 	unsigned count = 0;
292 
293 	spin_lock(&port->lock);
294 
295 	stat = sca_in(DSR_TX(port->chan), card); /* read DMA Status */
296 
297 	/* Reset DSR status bits */
298 	sca_out((stat & (DSR_EOT | DSR_EOM | DSR_BOF | DSR_COF)) | DSR_DWE,
299 		DSR_TX(port->chan), card);
300 
301 	while (1) {
302 		pkt_desc __iomem *desc = desc_address(port, port->txlast, 1);
303 		u8 stat = readb(&desc->stat);
304 
305 		if (!(stat & ST_TX_OWNRSHP))
306 			break; /* not yet transmitted */
307 		if (stat & ST_TX_UNDRRUN) {
308 			dev->stats.tx_errors++;
309 			dev->stats.tx_fifo_errors++;
310 		} else {
311 			dev->stats.tx_packets++;
312 			dev->stats.tx_bytes += readw(&desc->len);
313 		}
314 		writeb(0, &desc->stat);	/* Free descriptor */
315 		count++;
316 		port->txlast = (port->txlast + 1) % card->tx_ring_buffers;
317 	}
318 
319 	if (count)
320 		netif_wake_queue(dev);
321 	spin_unlock(&port->lock);
322 }
323 
324 
325 static int sca_poll(struct napi_struct *napi, int budget)
326 {
327 	port_t *port = container_of(napi, port_t, napi);
328 	u32 isr0 = sca_inl(ISR0, port->card);
329 	int received = 0;
330 
331 	if (isr0 & (port->chan ? 0x08000000 : 0x00080000))
332 		sca_msci_intr(port);
333 
334 	if (isr0 & (port->chan ? 0x00002000 : 0x00000020))
335 		sca_tx_done(port);
336 
337 	if (isr0 & (port->chan ? 0x00000200 : 0x00000002))
338 		received = sca_rx_done(port, budget);
339 
340 	if (received < budget) {
341 		napi_complete_done(napi, received);
342 		enable_intr(port);
343 	}
344 
345 	return received;
346 }
347 
348 static irqreturn_t sca_intr(int irq, void *dev_id)
349 {
350 	card_t *card = dev_id;
351 	u32 isr0 = sca_inl(ISR0, card);
352 	int i, handled = 0;
353 
354 	for (i = 0; i < 2; i++) {
355 		port_t *port = get_port(card, i);
356 		if (port && (isr0 & (i ? 0x08002200 : 0x00080022))) {
357 			handled = 1;
358 			disable_intr(port);
359 			napi_schedule(&port->napi);
360 		}
361 	}
362 
363 	return IRQ_RETVAL(handled);
364 }
365 
366 
367 static void sca_set_port(port_t *port)
368 {
369 	card_t* card = port->card;
370 	u16 msci = get_msci(port);
371 	u8 md2 = sca_in(msci + MD2, card);
372 	unsigned int tmc, br = 10, brv = 1024;
373 
374 
375 	if (port->settings.clock_rate > 0) {
376 		/* Try lower br for better accuracy*/
377 		do {
378 			br--;
379 			brv >>= 1; /* brv = 2^9 = 512 max in specs */
380 
381 			/* Baud Rate = CLOCK_BASE / TMC / 2^BR */
382 			tmc = CLOCK_BASE / brv / port->settings.clock_rate;
383 		}while (br > 1 && tmc <= 128);
384 
385 		if (tmc < 1) {
386 			tmc = 1;
387 			br = 0;	/* For baud=CLOCK_BASE we use tmc=1 br=0 */
388 			brv = 1;
389 		} else if (tmc > 255)
390 			tmc = 256; /* tmc=0 means 256 - low baud rates */
391 
392 		port->settings.clock_rate = CLOCK_BASE / brv / tmc;
393 	} else {
394 		br = 9; /* Minimum clock rate */
395 		tmc = 256;	/* 8bit = 0 */
396 		port->settings.clock_rate = CLOCK_BASE / (256 * 512);
397 	}
398 
399 	port->rxs = (port->rxs & ~CLK_BRG_MASK) | br;
400 	port->txs = (port->txs & ~CLK_BRG_MASK) | br;
401 	port->tmc = tmc;
402 
403 	/* baud divisor - time constant*/
404 	sca_out(port->tmc, msci + TMCR, card);
405 	sca_out(port->tmc, msci + TMCT, card);
406 
407 	/* Set BRG bits */
408 	sca_out(port->rxs, msci + RXS, card);
409 	sca_out(port->txs, msci + TXS, card);
410 
411 	if (port->settings.loopback)
412 		md2 |= MD2_LOOPBACK;
413 	else
414 		md2 &= ~MD2_LOOPBACK;
415 
416 	sca_out(md2, msci + MD2, card);
417 
418 }
419 
420 
421 static void sca_open(struct net_device *dev)
422 {
423 	port_t *port = dev_to_port(dev);
424 	card_t* card = port->card;
425 	u16 msci = get_msci(port);
426 	u8 md0, md2;
427 
428 	switch(port->encoding) {
429 	case ENCODING_NRZ:	md2 = MD2_NRZ;		break;
430 	case ENCODING_NRZI:	md2 = MD2_NRZI;		break;
431 	case ENCODING_FM_MARK:	md2 = MD2_FM_MARK;	break;
432 	case ENCODING_FM_SPACE:	md2 = MD2_FM_SPACE;	break;
433 	default:		md2 = MD2_MANCHESTER;
434 	}
435 
436 	if (port->settings.loopback)
437 		md2 |= MD2_LOOPBACK;
438 
439 	switch(port->parity) {
440 	case PARITY_CRC16_PR0:	     md0 = MD0_HDLC | MD0_CRC_16_0;  break;
441 	case PARITY_CRC16_PR1:	     md0 = MD0_HDLC | MD0_CRC_16;    break;
442 	case PARITY_CRC32_PR1_CCITT: md0 = MD0_HDLC | MD0_CRC_ITU32; break;
443 	case PARITY_CRC16_PR1_CCITT: md0 = MD0_HDLC | MD0_CRC_ITU;   break;
444 	default:		     md0 = MD0_HDLC | MD0_CRC_NONE;
445 	}
446 
447 	sca_out(CMD_RESET, msci + CMD, card);
448 	sca_out(md0, msci + MD0, card);
449 	sca_out(0x00, msci + MD1, card); /* no address field check */
450 	sca_out(md2, msci + MD2, card);
451 	sca_out(0x7E, msci + IDL, card); /* flag character 0x7E */
452 	/* Skip the rest of underrun frame */
453 	sca_out(CTL_IDLE | CTL_URCT | CTL_URSKP, msci + CTL, card);
454 	sca_out(0x0F, msci + RNR, card); /* +1=RX DMA activation condition */
455 	sca_out(0x3C, msci + TFS, card); /* +1 = TX start */
456 	sca_out(0x38, msci + TCR, card); /* =Critical TX DMA activ condition */
457 	sca_out(0x38, msci + TNR0, card); /* =TX DMA activation condition */
458 	sca_out(0x3F, msci + TNR1, card); /* +1=TX DMA deactivation condition*/
459 
460 /* We're using the following interrupts:
461    - RXINTA (DCD changes only)
462    - DMIB (EOM - single frame transfer complete)
463 */
464 	sca_outl(IE0_RXINTA | IE0_CDCD, msci + IE0, card);
465 
466 	sca_out(port->tmc, msci + TMCR, card);
467 	sca_out(port->tmc, msci + TMCT, card);
468 	sca_out(port->rxs, msci + RXS, card);
469 	sca_out(port->txs, msci + TXS, card);
470 	sca_out(CMD_TX_ENABLE, msci + CMD, card);
471 	sca_out(CMD_RX_ENABLE, msci + CMD, card);
472 
473 	sca_set_carrier(port);
474 	enable_intr(port);
475 	napi_enable(&port->napi);
476 	netif_start_queue(dev);
477 }
478 
479 
480 static void sca_close(struct net_device *dev)
481 {
482 	port_t *port = dev_to_port(dev);
483 
484 	/* reset channel */
485 	sca_out(CMD_RESET, get_msci(port) + CMD, port->card);
486 	disable_intr(port);
487 	napi_disable(&port->napi);
488 	netif_stop_queue(dev);
489 }
490 
491 
492 static int sca_attach(struct net_device *dev, unsigned short encoding,
493 		      unsigned short parity)
494 {
495 	if (encoding != ENCODING_NRZ &&
496 	    encoding != ENCODING_NRZI &&
497 	    encoding != ENCODING_FM_MARK &&
498 	    encoding != ENCODING_FM_SPACE &&
499 	    encoding != ENCODING_MANCHESTER)
500 		return -EINVAL;
501 
502 	if (parity != PARITY_NONE &&
503 	    parity != PARITY_CRC16_PR0 &&
504 	    parity != PARITY_CRC16_PR1 &&
505 	    parity != PARITY_CRC32_PR1_CCITT &&
506 	    parity != PARITY_CRC16_PR1_CCITT)
507 		return -EINVAL;
508 
509 	dev_to_port(dev)->encoding = encoding;
510 	dev_to_port(dev)->parity = parity;
511 	return 0;
512 }
513 
514 
515 #ifdef DEBUG_RINGS
516 static void sca_dump_rings(struct net_device *dev)
517 {
518 	port_t *port = dev_to_port(dev);
519 	card_t *card = port->card;
520 	u16 cnt;
521 
522 	printk(KERN_DEBUG "RX ring: CDA=%u EDA=%u DSR=%02X in=%u %sactive",
523 	       sca_inl(get_dmac_rx(port) + CDAL, card),
524 	       sca_inl(get_dmac_rx(port) + EDAL, card),
525 	       sca_in(DSR_RX(port->chan), card), port->rxin,
526 	       sca_in(DSR_RX(port->chan), card) & DSR_DE ? "" : "in");
527 	for (cnt = 0; cnt < port->card->rx_ring_buffers; cnt++)
528 		pr_cont(" %02X", readb(&(desc_address(port, cnt, 0)->stat)));
529 	pr_cont("\n");
530 
531 	printk(KERN_DEBUG "TX ring: CDA=%u EDA=%u DSR=%02X in=%u "
532 	       "last=%u %sactive",
533 	       sca_inl(get_dmac_tx(port) + CDAL, card),
534 	       sca_inl(get_dmac_tx(port) + EDAL, card),
535 	       sca_in(DSR_TX(port->chan), card), port->txin, port->txlast,
536 	       sca_in(DSR_TX(port->chan), card) & DSR_DE ? "" : "in");
537 
538 	for (cnt = 0; cnt < port->card->tx_ring_buffers; cnt++)
539 		pr_cont(" %02X", readb(&(desc_address(port, cnt, 1)->stat)));
540 	pr_cont("\n");
541 
542 	printk(KERN_DEBUG "MSCI: MD: %02x %02x %02x,"
543 	       " ST: %02x %02x %02x %02x %02x, FST: %02x CST: %02x %02x\n",
544 	       sca_in(get_msci(port) + MD0, card),
545 	       sca_in(get_msci(port) + MD1, card),
546 	       sca_in(get_msci(port) + MD2, card),
547 	       sca_in(get_msci(port) + ST0, card),
548 	       sca_in(get_msci(port) + ST1, card),
549 	       sca_in(get_msci(port) + ST2, card),
550 	       sca_in(get_msci(port) + ST3, card),
551 	       sca_in(get_msci(port) + ST4, card),
552 	       sca_in(get_msci(port) + FST, card),
553 	       sca_in(get_msci(port) + CST0, card),
554 	       sca_in(get_msci(port) + CST1, card));
555 
556 	printk(KERN_DEBUG "ILAR: %02x ISR: %08x %08x\n", sca_in(ILAR, card),
557 	       sca_inl(ISR0, card), sca_inl(ISR1, card));
558 }
559 #endif /* DEBUG_RINGS */
560 
561 
562 static netdev_tx_t sca_xmit(struct sk_buff *skb, struct net_device *dev)
563 {
564 	port_t *port = dev_to_port(dev);
565 	card_t *card = port->card;
566 	pkt_desc __iomem *desc;
567 	u32 buff, len;
568 
569 	spin_lock_irq(&port->lock);
570 
571 	desc = desc_address(port, port->txin + 1, 1);
572 	BUG_ON(readb(&desc->stat)); /* previous xmit should stop queue */
573 
574 #ifdef DEBUG_PKT
575 	printk(KERN_DEBUG "%s TX(%i):", dev->name, skb->len);
576 	debug_frame(skb);
577 #endif
578 
579 	desc = desc_address(port, port->txin, 1);
580 	buff = buffer_offset(port, port->txin, 1);
581 	len = skb->len;
582 	memcpy_toio(card->rambase + buff, skb->data, len);
583 
584 	writew(len, &desc->len);
585 	writeb(ST_TX_EOM, &desc->stat);
586 
587 	port->txin = (port->txin + 1) % card->tx_ring_buffers;
588 	sca_outl(desc_offset(port, port->txin, 1),
589 		 get_dmac_tx(port) + EDAL, card);
590 
591 	sca_out(DSR_DE, DSR_TX(port->chan), card); /* Enable TX DMA */
592 
593 	desc = desc_address(port, port->txin + 1, 1);
594 	if (readb(&desc->stat)) /* allow 1 packet gap */
595 		netif_stop_queue(dev);
596 
597 	spin_unlock_irq(&port->lock);
598 
599 	dev_kfree_skb(skb);
600 	return NETDEV_TX_OK;
601 }
602 
603 
604 static u32 sca_detect_ram(card_t *card, u8 __iomem *rambase, u32 ramsize)
605 {
606 	/* Round RAM size to 32 bits, fill from end to start */
607 	u32 i = ramsize &= ~3;
608 
609 	do {
610 		i -= 4;
611 		writel(i ^ 0x12345678, rambase + i);
612 	} while (i > 0);
613 
614 	for (i = 0; i < ramsize ; i += 4) {
615 		if (readl(rambase + i) != (i ^ 0x12345678))
616 			break;
617 	}
618 
619 	return i;
620 }
621 
622 
623 static void sca_init(card_t *card, int wait_states)
624 {
625 	sca_out(wait_states, WCRL, card); /* Wait Control */
626 	sca_out(wait_states, WCRM, card);
627 	sca_out(wait_states, WCRH, card);
628 
629 	sca_out(0, DMER, card);	/* DMA Master disable */
630 	sca_out(0x03, PCR, card); /* DMA priority */
631 	sca_out(0, DSR_RX(0), card); /* DMA disable - to halt state */
632 	sca_out(0, DSR_TX(0), card);
633 	sca_out(0, DSR_RX(1), card);
634 	sca_out(0, DSR_TX(1), card);
635 	sca_out(DMER_DME, DMER, card); /* DMA Master enable */
636 }
637