xref: /openbmc/linux/drivers/net/wan/hd64572.c (revision 9a29f5fc)
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 static inline u16 desc_offset(port_t *port, u16 desc, int transmit)
85 {
86 	/* Descriptor offset always fits in 16 bits */
87 	return desc_abs_number(port, desc, transmit) * sizeof(pkt_desc);
88 }
89 
90 static inline pkt_desc __iomem *desc_address(port_t *port, u16 desc,
91 					     int transmit)
92 {
93 	return (pkt_desc __iomem *)(port->card->rambase +
94 				    desc_offset(port, desc, transmit));
95 }
96 
97 static inline u32 buffer_offset(port_t *port, u16 desc, int transmit)
98 {
99 	return port->card->buff_offset +
100 		desc_abs_number(port, desc, transmit) * (u32)HDLC_MAX_MRU;
101 }
102 
103 static inline void sca_set_carrier(port_t *port)
104 {
105 	if (!(sca_in(get_msci(port) + ST3, port->card) & ST3_DCD)) {
106 #ifdef DEBUG_LINK
107 		printk(KERN_DEBUG "%s: sca_set_carrier on\n",
108 		       port->netdev.name);
109 #endif
110 		netif_carrier_on(port->netdev);
111 	} else {
112 #ifdef DEBUG_LINK
113 		printk(KERN_DEBUG "%s: sca_set_carrier off\n",
114 		       port->netdev.name);
115 #endif
116 		netif_carrier_off(port->netdev);
117 	}
118 }
119 
120 static void sca_init_port(port_t *port)
121 {
122 	card_t *card = port->card;
123 	u16 dmac_rx = get_dmac_rx(port), dmac_tx = get_dmac_tx(port);
124 	int transmit, i;
125 
126 	port->rxin = 0;
127 	port->txin = 0;
128 	port->txlast = 0;
129 
130 	for (transmit = 0; transmit < 2; transmit++) {
131 		u16 buffs = transmit ? card->tx_ring_buffers
132 			: card->rx_ring_buffers;
133 
134 		for (i = 0; i < buffs; i++) {
135 			pkt_desc __iomem *desc = desc_address(port, i, transmit);
136 			u16 chain_off = desc_offset(port, i + 1, transmit);
137 			u32 buff_off = buffer_offset(port, i, transmit);
138 
139 			writel(chain_off, &desc->cp);
140 			writel(buff_off, &desc->bp);
141 			writew(0, &desc->len);
142 			writeb(0, &desc->stat);
143 		}
144 	}
145 
146 	/* DMA disable - to halt state */
147 	sca_out(0, DSR_RX(port->chan), card);
148 	sca_out(0, DSR_TX(port->chan), card);
149 
150 	/* software ABORT - to initial state */
151 	sca_out(DCR_ABORT, DCR_RX(port->chan), card);
152 	sca_out(DCR_ABORT, DCR_TX(port->chan), card);
153 
154 	/* current desc addr */
155 	sca_outl(desc_offset(port, 0, 0), dmac_rx + CDAL, card);
156 	sca_outl(desc_offset(port, card->tx_ring_buffers - 1, 0),
157 		 dmac_rx + EDAL, card);
158 	sca_outl(desc_offset(port, 0, 1), dmac_tx + CDAL, card);
159 	sca_outl(desc_offset(port, 0, 1), dmac_tx + EDAL, card);
160 
161 	/* clear frame end interrupt counter */
162 	sca_out(DCR_CLEAR_EOF, DCR_RX(port->chan), card);
163 	sca_out(DCR_CLEAR_EOF, DCR_TX(port->chan), card);
164 
165 	/* Receive */
166 	sca_outw(HDLC_MAX_MRU, dmac_rx + BFLL, card); /* set buffer length */
167 	sca_out(0x14, DMR_RX(port->chan), card); /* Chain mode, Multi-frame */
168 	sca_out(DIR_EOME, DIR_RX(port->chan), card); /* enable interrupts */
169 	sca_out(DSR_DE, DSR_RX(port->chan), card); /* DMA enable */
170 
171 	/* Transmit */
172 	sca_out(0x14, DMR_TX(port->chan), card); /* Chain mode, Multi-frame */
173 	sca_out(DIR_EOME, DIR_TX(port->chan), card); /* enable interrupts */
174 
175 	sca_set_carrier(port);
176 	netif_napi_add_weight(port->netdev, &port->napi, sca_poll,
177 			      NAPI_WEIGHT);
178 }
179 
180 /* MSCI interrupt service */
181 static inline void sca_msci_intr(port_t *port)
182 {
183 	u16 msci = get_msci(port);
184 	card_t *card = port->card;
185 
186 	if (sca_in(msci + ST1, card) & ST1_CDCD) {
187 		/* Reset MSCI CDCD status bit */
188 		sca_out(ST1_CDCD, msci + ST1, card);
189 		sca_set_carrier(port);
190 	}
191 }
192 
193 static inline void sca_rx(card_t *card, port_t *port, pkt_desc __iomem *desc,
194 			  u16 rxin)
195 {
196 	struct net_device *dev = port->netdev;
197 	struct sk_buff *skb;
198 	u16 len;
199 	u32 buff;
200 
201 	len = readw(&desc->len);
202 	skb = dev_alloc_skb(len);
203 	if (!skb) {
204 		dev->stats.rx_dropped++;
205 		return;
206 	}
207 
208 	buff = buffer_offset(port, rxin, 0);
209 	memcpy_fromio(skb->data, card->rambase + buff, len);
210 
211 	skb_put(skb, len);
212 #ifdef DEBUG_PKT
213 	printk(KERN_DEBUG "%s RX(%i):", dev->name, skb->len);
214 	debug_frame(skb);
215 #endif
216 	dev->stats.rx_packets++;
217 	dev->stats.rx_bytes += skb->len;
218 	skb->protocol = hdlc_type_trans(skb, dev);
219 	netif_receive_skb(skb);
220 }
221 
222 /* Receive DMA service */
223 static inline int sca_rx_done(port_t *port, int budget)
224 {
225 	struct net_device *dev = port->netdev;
226 	u16 dmac = get_dmac_rx(port);
227 	card_t *card = port->card;
228 	u8 stat = sca_in(DSR_RX(port->chan), card); /* read DMA Status */
229 	int received = 0;
230 
231 	/* Reset DSR status bits */
232 	sca_out((stat & (DSR_EOT | DSR_EOM | DSR_BOF | DSR_COF)) | DSR_DWE,
233 		DSR_RX(port->chan), card);
234 
235 	if (stat & DSR_BOF)
236 		/* Dropped one or more frames */
237 		dev->stats.rx_over_errors++;
238 
239 	while (received < budget) {
240 		u32 desc_off = desc_offset(port, port->rxin, 0);
241 		pkt_desc __iomem *desc;
242 		u32 cda = sca_inl(dmac + CDAL, card);
243 
244 		if ((cda >= desc_off) && (cda < desc_off + sizeof(pkt_desc)))
245 			break;	/* No frame received */
246 
247 		desc = desc_address(port, port->rxin, 0);
248 		stat = readb(&desc->stat);
249 		if (!(stat & ST_RX_EOM))
250 			port->rxpart = 1; /* partial frame received */
251 		else if ((stat & ST_ERROR_MASK) || port->rxpart) {
252 			dev->stats.rx_errors++;
253 			if (stat & ST_RX_OVERRUN)
254 				dev->stats.rx_fifo_errors++;
255 			else if ((stat & (ST_RX_SHORT | ST_RX_ABORT |
256 					  ST_RX_RESBIT)) || port->rxpart)
257 				dev->stats.rx_frame_errors++;
258 			else if (stat & ST_RX_CRC)
259 				dev->stats.rx_crc_errors++;
260 			if (stat & ST_RX_EOM)
261 				port->rxpart = 0; /* received last fragment */
262 		} else {
263 			sca_rx(card, port, desc, port->rxin);
264 			received++;
265 		}
266 
267 		/* Set new error descriptor address */
268 		sca_outl(desc_off, dmac + EDAL, card);
269 		port->rxin = (port->rxin + 1) % card->rx_ring_buffers;
270 	}
271 
272 	/* make sure RX DMA is enabled */
273 	sca_out(DSR_DE, DSR_RX(port->chan), card);
274 	return received;
275 }
276 
277 /* Transmit DMA service */
278 static inline void sca_tx_done(port_t *port)
279 {
280 	struct net_device *dev = port->netdev;
281 	card_t *card = port->card;
282 	u8 stat;
283 	unsigned count = 0;
284 
285 	spin_lock(&port->lock);
286 
287 	stat = sca_in(DSR_TX(port->chan), card); /* read DMA Status */
288 
289 	/* Reset DSR status bits */
290 	sca_out((stat & (DSR_EOT | DSR_EOM | DSR_BOF | DSR_COF)) | DSR_DWE,
291 		DSR_TX(port->chan), card);
292 
293 	while (1) {
294 		pkt_desc __iomem *desc = desc_address(port, port->txlast, 1);
295 		u8 stat = readb(&desc->stat);
296 
297 		if (!(stat & ST_TX_OWNRSHP))
298 			break; /* not yet transmitted */
299 		if (stat & ST_TX_UNDRRUN) {
300 			dev->stats.tx_errors++;
301 			dev->stats.tx_fifo_errors++;
302 		} else {
303 			dev->stats.tx_packets++;
304 			dev->stats.tx_bytes += readw(&desc->len);
305 		}
306 		writeb(0, &desc->stat);	/* Free descriptor */
307 		count++;
308 		port->txlast = (port->txlast + 1) % card->tx_ring_buffers;
309 	}
310 
311 	if (count)
312 		netif_wake_queue(dev);
313 	spin_unlock(&port->lock);
314 }
315 
316 static int sca_poll(struct napi_struct *napi, int budget)
317 {
318 	port_t *port = container_of(napi, port_t, napi);
319 	u32 isr0 = sca_inl(ISR0, port->card);
320 	int received = 0;
321 
322 	if (isr0 & (port->chan ? 0x08000000 : 0x00080000))
323 		sca_msci_intr(port);
324 
325 	if (isr0 & (port->chan ? 0x00002000 : 0x00000020))
326 		sca_tx_done(port);
327 
328 	if (isr0 & (port->chan ? 0x00000200 : 0x00000002))
329 		received = sca_rx_done(port, budget);
330 
331 	if (received < budget) {
332 		napi_complete_done(napi, received);
333 		enable_intr(port);
334 	}
335 
336 	return received;
337 }
338 
339 static irqreturn_t sca_intr(int irq, void *dev_id)
340 {
341 	card_t *card = dev_id;
342 	u32 isr0 = sca_inl(ISR0, card);
343 	int i, handled = 0;
344 
345 	for (i = 0; i < 2; i++) {
346 		port_t *port = get_port(card, i);
347 		if (port && (isr0 & (i ? 0x08002200 : 0x00080022))) {
348 			handled = 1;
349 			disable_intr(port);
350 			napi_schedule(&port->napi);
351 		}
352 	}
353 
354 	return IRQ_RETVAL(handled);
355 }
356 
357 static void sca_set_port(port_t *port)
358 {
359 	card_t *card = port->card;
360 	u16 msci = get_msci(port);
361 	u8 md2 = sca_in(msci + MD2, card);
362 	unsigned int tmc, br = 10, brv = 1024;
363 
364 	if (port->settings.clock_rate > 0) {
365 		/* Try lower br for better accuracy*/
366 		do {
367 			br--;
368 			brv >>= 1; /* brv = 2^9 = 512 max in specs */
369 
370 			/* Baud Rate = CLOCK_BASE / TMC / 2^BR */
371 			tmc = CLOCK_BASE / brv / port->settings.clock_rate;
372 		} while (br > 1 && tmc <= 128);
373 
374 		if (tmc < 1) {
375 			tmc = 1;
376 			br = 0;	/* For baud=CLOCK_BASE we use tmc=1 br=0 */
377 			brv = 1;
378 		} else if (tmc > 255) {
379 			tmc = 256; /* tmc=0 means 256 - low baud rates */
380 		}
381 
382 		port->settings.clock_rate = CLOCK_BASE / brv / tmc;
383 	} else {
384 		br = 9; /* Minimum clock rate */
385 		tmc = 256;	/* 8bit = 0 */
386 		port->settings.clock_rate = CLOCK_BASE / (256 * 512);
387 	}
388 
389 	port->rxs = (port->rxs & ~CLK_BRG_MASK) | br;
390 	port->txs = (port->txs & ~CLK_BRG_MASK) | br;
391 	port->tmc = tmc;
392 
393 	/* baud divisor - time constant*/
394 	sca_out(port->tmc, msci + TMCR, card);
395 	sca_out(port->tmc, msci + TMCT, card);
396 
397 	/* Set BRG bits */
398 	sca_out(port->rxs, msci + RXS, card);
399 	sca_out(port->txs, msci + TXS, card);
400 
401 	if (port->settings.loopback)
402 		md2 |= MD2_LOOPBACK;
403 	else
404 		md2 &= ~MD2_LOOPBACK;
405 
406 	sca_out(md2, msci + MD2, card);
407 }
408 
409 static void sca_open(struct net_device *dev)
410 {
411 	port_t *port = dev_to_port(dev);
412 	card_t *card = port->card;
413 	u16 msci = get_msci(port);
414 	u8 md0, md2;
415 
416 	switch (port->encoding) {
417 	case ENCODING_NRZ:
418 		md2 = MD2_NRZ;
419 		break;
420 	case ENCODING_NRZI:
421 		md2 = MD2_NRZI;
422 		break;
423 	case ENCODING_FM_MARK:
424 		md2 = MD2_FM_MARK;
425 		break;
426 	case ENCODING_FM_SPACE:
427 		md2 = MD2_FM_SPACE;
428 		break;
429 	default:
430 		md2 = MD2_MANCHESTER;
431 	}
432 
433 	if (port->settings.loopback)
434 		md2 |= MD2_LOOPBACK;
435 
436 	switch (port->parity) {
437 	case PARITY_CRC16_PR0:
438 		md0 = MD0_HDLC | MD0_CRC_16_0;
439 		break;
440 	case PARITY_CRC16_PR1:
441 		md0 = MD0_HDLC | MD0_CRC_16;
442 		break;
443 	case PARITY_CRC32_PR1_CCITT:
444 		md0 = MD0_HDLC | MD0_CRC_ITU32;
445 		break;
446 	case PARITY_CRC16_PR1_CCITT:
447 		md0 = MD0_HDLC | MD0_CRC_ITU;
448 		break;
449 	default:
450 		md0 = MD0_HDLC | MD0_CRC_NONE;
451 	}
452 
453 	sca_out(CMD_RESET, msci + CMD, card);
454 	sca_out(md0, msci + MD0, card);
455 	sca_out(0x00, msci + MD1, card); /* no address field check */
456 	sca_out(md2, msci + MD2, card);
457 	sca_out(0x7E, msci + IDL, card); /* flag character 0x7E */
458 	/* Skip the rest of underrun frame */
459 	sca_out(CTL_IDLE | CTL_URCT | CTL_URSKP, msci + CTL, card);
460 	sca_out(0x0F, msci + RNR, card); /* +1=RX DMA activation condition */
461 	sca_out(0x3C, msci + TFS, card); /* +1 = TX start */
462 	sca_out(0x38, msci + TCR, card); /* =Critical TX DMA activ condition */
463 	sca_out(0x38, msci + TNR0, card); /* =TX DMA activation condition */
464 	sca_out(0x3F, msci + TNR1, card); /* +1=TX DMA deactivation condition*/
465 
466 /* We're using the following interrupts:
467    - RXINTA (DCD changes only)
468    - DMIB (EOM - single frame transfer complete)
469 */
470 	sca_outl(IE0_RXINTA | IE0_CDCD, msci + IE0, card);
471 
472 	sca_out(port->tmc, msci + TMCR, card);
473 	sca_out(port->tmc, msci + TMCT, card);
474 	sca_out(port->rxs, msci + RXS, card);
475 	sca_out(port->txs, msci + TXS, card);
476 	sca_out(CMD_TX_ENABLE, msci + CMD, card);
477 	sca_out(CMD_RX_ENABLE, msci + CMD, card);
478 
479 	sca_set_carrier(port);
480 	enable_intr(port);
481 	napi_enable(&port->napi);
482 	netif_start_queue(dev);
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 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 #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 static netdev_tx_t sca_xmit(struct sk_buff *skb, struct net_device *dev)
565 {
566 	port_t *port = dev_to_port(dev);
567 	card_t *card = port->card;
568 	pkt_desc __iomem *desc;
569 	u32 buff, len;
570 
571 	spin_lock_irq(&port->lock);
572 
573 	desc = desc_address(port, port->txin + 1, 1);
574 	BUG_ON(readb(&desc->stat)); /* previous xmit should stop queue */
575 
576 #ifdef DEBUG_PKT
577 	printk(KERN_DEBUG "%s TX(%i):", dev->name, skb->len);
578 	debug_frame(skb);
579 #endif
580 
581 	desc = desc_address(port, port->txin, 1);
582 	buff = buffer_offset(port, port->txin, 1);
583 	len = skb->len;
584 	memcpy_toio(card->rambase + buff, skb->data, len);
585 
586 	writew(len, &desc->len);
587 	writeb(ST_TX_EOM, &desc->stat);
588 
589 	port->txin = (port->txin + 1) % card->tx_ring_buffers;
590 	sca_outl(desc_offset(port, port->txin, 1),
591 		 get_dmac_tx(port) + EDAL, card);
592 
593 	sca_out(DSR_DE, DSR_TX(port->chan), card); /* Enable TX DMA */
594 
595 	desc = desc_address(port, port->txin + 1, 1);
596 	if (readb(&desc->stat)) /* allow 1 packet gap */
597 		netif_stop_queue(dev);
598 
599 	spin_unlock_irq(&port->lock);
600 
601 	dev_kfree_skb(skb);
602 	return NETDEV_TX_OK;
603 }
604 
605 static u32 sca_detect_ram(card_t *card, u8 __iomem *rambase, u32 ramsize)
606 {
607 	/* Round RAM size to 32 bits, fill from end to start */
608 	u32 i = ramsize &= ~3;
609 
610 	do {
611 		i -= 4;
612 		writel(i ^ 0x12345678, rambase + i);
613 	} while (i > 0);
614 
615 	for (i = 0; i < ramsize ; i += 4) {
616 		if (readl(rambase + i) != (i ^ 0x12345678))
617 			break;
618 	}
619 
620 	return i;
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