xref: /openbmc/u-boot/drivers/net/ep93xx_eth.c (revision 85231c08)
1 /*
2  * Cirrus Logic EP93xx ethernet MAC / MII driver.
3  *
4  * Copyright (C) 2010, 2009
5  * Matthias Kaehlcke <matthias@kaehlcke.net>
6  *
7  * Copyright (C) 2004, 2005
8  * Cory T. Tusar, Videon Central, Inc., <ctusar@videon-central.com>
9  *
10  * Based on the original eth.[ch] Cirrus Logic EP93xx Rev D. Ethernet Driver,
11  * which is
12  *
13  * (C) Copyright 2002 2003
14  * Adam Bezanson, Network Audio Technologies, Inc.
15  * <bezanson@netaudiotech.com>
16  *
17  * SPDX-License-Identifier:	GPL-2.0+
18  */
19 
20 #include <command.h>
21 #include <common.h>
22 #include <asm/arch/ep93xx.h>
23 #include <asm/io.h>
24 #include <malloc.h>
25 #include <miiphy.h>
26 #include <linux/types.h>
27 #include "ep93xx_eth.h"
28 
29 #define GET_PRIV(eth_dev)	((struct ep93xx_priv *)(eth_dev)->priv)
30 #define GET_REGS(eth_dev)	(GET_PRIV(eth_dev)->regs)
31 
32 /* ep93xx_miiphy ops forward declarations */
33 static int ep93xx_miiphy_read(struct mii_dev *bus, int addr, int devad,
34 			      int reg);
35 static int ep93xx_miiphy_write(struct mii_dev *bus, int addr, int devad,
36 			       int reg, u16 value);
37 
38 #if defined(EP93XX_MAC_DEBUG)
39 /**
40  * Dump ep93xx_mac values to the terminal.
41  */
42 static void dump_dev(struct eth_device *dev)
43 {
44 	struct ep93xx_priv *priv = GET_PRIV(dev);
45 	int i;
46 
47 	printf("\ndump_dev()\n");
48 	printf("  rx_dq.base	     %p\n", priv->rx_dq.base);
49 	printf("  rx_dq.current	     %p\n", priv->rx_dq.current);
50 	printf("  rx_dq.end	     %p\n", priv->rx_dq.end);
51 	printf("  rx_sq.base	     %p\n", priv->rx_sq.base);
52 	printf("  rx_sq.current	     %p\n", priv->rx_sq.current);
53 	printf("  rx_sq.end	     %p\n", priv->rx_sq.end);
54 
55 	for (i = 0; i < NUMRXDESC; i++)
56 		printf("  rx_buffer[%2.d]      %p\n", i, net_rx_packets[i]);
57 
58 	printf("  tx_dq.base	     %p\n", priv->tx_dq.base);
59 	printf("  tx_dq.current	     %p\n", priv->tx_dq.current);
60 	printf("  tx_dq.end	     %p\n", priv->tx_dq.end);
61 	printf("  tx_sq.base	     %p\n", priv->tx_sq.base);
62 	printf("  tx_sq.current	     %p\n", priv->tx_sq.current);
63 	printf("  tx_sq.end	     %p\n", priv->tx_sq.end);
64 }
65 
66 /**
67  * Dump all RX status queue entries to the terminal.
68  */
69 static void dump_rx_status_queue(struct eth_device *dev)
70 {
71 	struct ep93xx_priv *priv = GET_PRIV(dev);
72 	int i;
73 
74 	printf("\ndump_rx_status_queue()\n");
75 	printf("  descriptor address	 word1		 word2\n");
76 	for (i = 0; i < NUMRXDESC; i++) {
77 		printf("  [ %p ]	     %08X	 %08X\n",
78 			priv->rx_sq.base + i,
79 			(priv->rx_sq.base + i)->word1,
80 			(priv->rx_sq.base + i)->word2);
81 	}
82 }
83 
84 /**
85  * Dump all RX descriptor queue entries to the terminal.
86  */
87 static void dump_rx_descriptor_queue(struct eth_device *dev)
88 {
89 	struct ep93xx_priv *priv = GET_PRIV(dev);
90 	int i;
91 
92 	printf("\ndump_rx_descriptor_queue()\n");
93 	printf("  descriptor address	 word1		 word2\n");
94 	for (i = 0; i < NUMRXDESC; i++) {
95 		printf("  [ %p ]	     %08X	 %08X\n",
96 			priv->rx_dq.base + i,
97 			(priv->rx_dq.base + i)->word1,
98 			(priv->rx_dq.base + i)->word2);
99 	}
100 }
101 
102 /**
103  * Dump all TX descriptor queue entries to the terminal.
104  */
105 static void dump_tx_descriptor_queue(struct eth_device *dev)
106 {
107 	struct ep93xx_priv *priv = GET_PRIV(dev);
108 	int i;
109 
110 	printf("\ndump_tx_descriptor_queue()\n");
111 	printf("  descriptor address	 word1		 word2\n");
112 	for (i = 0; i < NUMTXDESC; i++) {
113 		printf("  [ %p ]	     %08X	 %08X\n",
114 			priv->tx_dq.base + i,
115 			(priv->tx_dq.base + i)->word1,
116 			(priv->tx_dq.base + i)->word2);
117 	}
118 }
119 
120 /**
121  * Dump all TX status queue entries to the terminal.
122  */
123 static void dump_tx_status_queue(struct eth_device *dev)
124 {
125 	struct ep93xx_priv *priv = GET_PRIV(dev);
126 	int i;
127 
128 	printf("\ndump_tx_status_queue()\n");
129 	printf("  descriptor address	 word1\n");
130 	for (i = 0; i < NUMTXDESC; i++) {
131 		printf("  [ %p ]	     %08X\n",
132 			priv->rx_sq.base + i,
133 			(priv->rx_sq.base + i)->word1);
134 	}
135 }
136 #else
137 #define dump_dev(x)
138 #define dump_rx_descriptor_queue(x)
139 #define dump_rx_status_queue(x)
140 #define dump_tx_descriptor_queue(x)
141 #define dump_tx_status_queue(x)
142 #endif	/* defined(EP93XX_MAC_DEBUG) */
143 
144 /**
145  * Reset the EP93xx MAC by twiddling the soft reset bit and spinning until
146  * it's cleared.
147  */
148 static void ep93xx_mac_reset(struct eth_device *dev)
149 {
150 	struct mac_regs *mac = GET_REGS(dev);
151 	uint32_t value;
152 
153 	debug("+ep93xx_mac_reset");
154 
155 	value = readl(&mac->selfctl);
156 	value |= SELFCTL_RESET;
157 	writel(value, &mac->selfctl);
158 
159 	while (readl(&mac->selfctl) & SELFCTL_RESET)
160 		; /* noop */
161 
162 	debug("-ep93xx_mac_reset");
163 }
164 
165 /* Eth device open */
166 static int ep93xx_eth_open(struct eth_device *dev, bd_t *bd)
167 {
168 	struct ep93xx_priv *priv = GET_PRIV(dev);
169 	struct mac_regs *mac = GET_REGS(dev);
170 	uchar *mac_addr = dev->enetaddr;
171 	int i;
172 
173 	debug("+ep93xx_eth_open");
174 
175 	/* Reset the MAC */
176 	ep93xx_mac_reset(dev);
177 
178 	/* Reset the descriptor queues' current and end address values */
179 	priv->tx_dq.current = priv->tx_dq.base;
180 	priv->tx_dq.end = (priv->tx_dq.base + NUMTXDESC);
181 
182 	priv->tx_sq.current = priv->tx_sq.base;
183 	priv->tx_sq.end = (priv->tx_sq.base + NUMTXDESC);
184 
185 	priv->rx_dq.current = priv->rx_dq.base;
186 	priv->rx_dq.end = (priv->rx_dq.base + NUMRXDESC);
187 
188 	priv->rx_sq.current = priv->rx_sq.base;
189 	priv->rx_sq.end = (priv->rx_sq.base + NUMRXDESC);
190 
191 	/*
192 	 * Set the transmit descriptor and status queues' base address,
193 	 * current address, and length registers.  Set the maximum frame
194 	 * length and threshold. Enable the transmit descriptor processor.
195 	 */
196 	writel((uint32_t)priv->tx_dq.base, &mac->txdq.badd);
197 	writel((uint32_t)priv->tx_dq.base, &mac->txdq.curadd);
198 	writel(sizeof(struct tx_descriptor) * NUMTXDESC, &mac->txdq.blen);
199 
200 	writel((uint32_t)priv->tx_sq.base, &mac->txstsq.badd);
201 	writel((uint32_t)priv->tx_sq.base, &mac->txstsq.curadd);
202 	writel(sizeof(struct tx_status) * NUMTXDESC, &mac->txstsq.blen);
203 
204 	writel(0x00040000, &mac->txdthrshld);
205 	writel(0x00040000, &mac->txststhrshld);
206 
207 	writel((TXSTARTMAX << 0) | (PKTSIZE_ALIGN << 16), &mac->maxfrmlen);
208 	writel(BMCTL_TXEN, &mac->bmctl);
209 
210 	/*
211 	 * Set the receive descriptor and status queues' base address,
212 	 * current address, and length registers.  Enable the receive
213 	 * descriptor processor.
214 	 */
215 	writel((uint32_t)priv->rx_dq.base, &mac->rxdq.badd);
216 	writel((uint32_t)priv->rx_dq.base, &mac->rxdq.curadd);
217 	writel(sizeof(struct rx_descriptor) * NUMRXDESC, &mac->rxdq.blen);
218 
219 	writel((uint32_t)priv->rx_sq.base, &mac->rxstsq.badd);
220 	writel((uint32_t)priv->rx_sq.base, &mac->rxstsq.curadd);
221 	writel(sizeof(struct rx_status) * NUMRXDESC, &mac->rxstsq.blen);
222 
223 	writel(0x00040000, &mac->rxdthrshld);
224 
225 	writel(BMCTL_RXEN, &mac->bmctl);
226 
227 	writel(0x00040000, &mac->rxststhrshld);
228 
229 	/* Wait until the receive descriptor processor is active */
230 	while (!(readl(&mac->bmsts) & BMSTS_RXACT))
231 		; /* noop */
232 
233 	/*
234 	 * Initialize the RX descriptor queue. Clear the TX descriptor queue.
235 	 * Clear the RX and TX status queues. Enqueue the RX descriptor and
236 	 * status entries to the MAC.
237 	 */
238 	for (i = 0; i < NUMRXDESC; i++) {
239 		/* set buffer address */
240 		(priv->rx_dq.base + i)->word1 = (uint32_t)net_rx_packets[i];
241 
242 		/* set buffer length, clear buffer index and NSOF */
243 		(priv->rx_dq.base + i)->word2 = PKTSIZE_ALIGN;
244 	}
245 
246 	memset(priv->tx_dq.base, 0,
247 		(sizeof(struct tx_descriptor) * NUMTXDESC));
248 	memset(priv->rx_sq.base, 0,
249 		(sizeof(struct rx_status) * NUMRXDESC));
250 	memset(priv->tx_sq.base, 0,
251 		(sizeof(struct tx_status) * NUMTXDESC));
252 
253 	writel(NUMRXDESC, &mac->rxdqenq);
254 	writel(NUMRXDESC, &mac->rxstsqenq);
255 
256 	/* Set the primary MAC address */
257 	writel(AFP_IAPRIMARY, &mac->afp);
258 	writel(mac_addr[0] | (mac_addr[1] << 8) |
259 		(mac_addr[2] << 16) | (mac_addr[3] << 24),
260 		&mac->indad);
261 	writel(mac_addr[4] | (mac_addr[5] << 8), &mac->indad_upper);
262 
263 	/* Turn on RX and TX */
264 	writel(RXCTL_IA0 | RXCTL_BA | RXCTL_SRXON |
265 		RXCTL_RCRCA | RXCTL_MA, &mac->rxctl);
266 	writel(TXCTL_STXON, &mac->txctl);
267 
268 	/* Dump data structures if we're debugging */
269 	dump_dev(dev);
270 	dump_rx_descriptor_queue(dev);
271 	dump_rx_status_queue(dev);
272 	dump_tx_descriptor_queue(dev);
273 	dump_tx_status_queue(dev);
274 
275 	debug("-ep93xx_eth_open");
276 
277 	return 1;
278 }
279 
280 /**
281  * Halt EP93xx MAC transmit and receive by clearing the TxCTL and RxCTL
282  * registers.
283  */
284 static void ep93xx_eth_close(struct eth_device *dev)
285 {
286 	struct mac_regs *mac = GET_REGS(dev);
287 
288 	debug("+ep93xx_eth_close");
289 
290 	writel(0x00000000, &mac->rxctl);
291 	writel(0x00000000, &mac->txctl);
292 
293 	debug("-ep93xx_eth_close");
294 }
295 
296 /**
297  * Copy a frame of data from the MAC into the protocol layer for further
298  * processing.
299  */
300 static int ep93xx_eth_rcv_packet(struct eth_device *dev)
301 {
302 	struct mac_regs *mac = GET_REGS(dev);
303 	struct ep93xx_priv *priv = GET_PRIV(dev);
304 	int len = -1;
305 
306 	debug("+ep93xx_eth_rcv_packet");
307 
308 	if (RX_STATUS_RFP(priv->rx_sq.current)) {
309 		if (RX_STATUS_RWE(priv->rx_sq.current)) {
310 			/*
311 			 * We have a good frame. Extract the frame's length
312 			 * from the current rx_status_queue entry, and copy
313 			 * the frame's data into net_rx_packets[] of the
314 			 * protocol stack. We track the total number of
315 			 * bytes in the frame (nbytes_frame) which will be
316 			 * used when we pass the data off to the protocol
317 			 * layer via net_process_received_packet().
318 			 */
319 			len = RX_STATUS_FRAME_LEN(priv->rx_sq.current);
320 
321 			net_process_received_packet(
322 				(uchar *)priv->rx_dq.current->word1, len);
323 
324 			debug("reporting %d bytes...\n", len);
325 		} else {
326 			/* Do we have an erroneous packet? */
327 			pr_err("packet rx error, status %08X %08X",
328 				priv->rx_sq.current->word1,
329 				priv->rx_sq.current->word2);
330 			dump_rx_descriptor_queue(dev);
331 			dump_rx_status_queue(dev);
332 		}
333 
334 		/*
335 		 * Clear the associated status queue entry, and
336 		 * increment our current pointers to the next RX
337 		 * descriptor and status queue entries (making sure
338 		 * we wrap properly).
339 		 */
340 		memset((void *)priv->rx_sq.current, 0,
341 			sizeof(struct rx_status));
342 
343 		priv->rx_sq.current++;
344 		if (priv->rx_sq.current >= priv->rx_sq.end)
345 			priv->rx_sq.current = priv->rx_sq.base;
346 
347 		priv->rx_dq.current++;
348 		if (priv->rx_dq.current >= priv->rx_dq.end)
349 			priv->rx_dq.current = priv->rx_dq.base;
350 
351 		/*
352 		 * Finally, return the RX descriptor and status entries
353 		 * back to the MAC engine, and loop again, checking for
354 		 * more descriptors to process.
355 		 */
356 		writel(1, &mac->rxdqenq);
357 		writel(1, &mac->rxstsqenq);
358 	} else {
359 		len = 0;
360 	}
361 
362 	debug("-ep93xx_eth_rcv_packet %d", len);
363 	return len;
364 }
365 
366 /**
367  * Send a block of data via ethernet.
368  */
369 static int ep93xx_eth_send_packet(struct eth_device *dev,
370 				void * const packet, int const length)
371 {
372 	struct mac_regs *mac = GET_REGS(dev);
373 	struct ep93xx_priv *priv = GET_PRIV(dev);
374 	int ret = -1;
375 
376 	debug("+ep93xx_eth_send_packet");
377 
378 	/* Parameter check */
379 	BUG_ON(packet == NULL);
380 
381 	/*
382 	 * Initialize the TX descriptor queue with the new packet's info.
383 	 * Clear the associated status queue entry. Enqueue the packet
384 	 * to the MAC for transmission.
385 	 */
386 
387 	/* set buffer address */
388 	priv->tx_dq.current->word1 = (uint32_t)packet;
389 
390 	/* set buffer length and EOF bit */
391 	priv->tx_dq.current->word2 = length | TX_DESC_EOF;
392 
393 	/* clear tx status */
394 	priv->tx_sq.current->word1 = 0;
395 
396 	/* enqueue the TX descriptor */
397 	writel(1, &mac->txdqenq);
398 
399 	/* wait for the frame to become processed */
400 	while (!TX_STATUS_TXFP(priv->tx_sq.current))
401 		; /* noop */
402 
403 	if (!TX_STATUS_TXWE(priv->tx_sq.current)) {
404 		pr_err("packet tx error, status %08X",
405 			priv->tx_sq.current->word1);
406 		dump_tx_descriptor_queue(dev);
407 		dump_tx_status_queue(dev);
408 
409 		/* TODO: Add better error handling? */
410 		goto eth_send_out;
411 	}
412 
413 	ret = 0;
414 	/* Fall through */
415 
416 eth_send_out:
417 	debug("-ep93xx_eth_send_packet %d", ret);
418 	return ret;
419 }
420 
421 #if defined(CONFIG_MII)
422 int ep93xx_miiphy_initialize(bd_t * const bd)
423 {
424 	int retval;
425 	struct mii_dev *mdiodev = mdio_alloc();
426 	if (!mdiodev)
427 		return -ENOMEM;
428 	strncpy(mdiodev->name, "ep93xx_eth0", MDIO_NAME_LEN);
429 	mdiodev->read = ep93xx_miiphy_read;
430 	mdiodev->write = ep93xx_miiphy_write;
431 
432 	retval = mdio_register(mdiodev);
433 	if (retval < 0)
434 		return retval;
435 	return 0;
436 }
437 #endif
438 
439 /**
440  * Initialize the EP93xx MAC.  The MAC hardware is reset.  Buffers are
441  * allocated, if necessary, for the TX and RX descriptor and status queues,
442  * as well as for received packets.  The EP93XX MAC hardware is initialized.
443  * Transmit and receive operations are enabled.
444  */
445 int ep93xx_eth_initialize(u8 dev_num, int base_addr)
446 {
447 	int ret = -1;
448 	struct eth_device *dev;
449 	struct ep93xx_priv *priv;
450 
451 	debug("+ep93xx_eth_initialize");
452 
453 	priv = malloc(sizeof(*priv));
454 	if (!priv) {
455 		pr_err("malloc() failed");
456 		goto eth_init_failed_0;
457 	}
458 	memset(priv, 0, sizeof(*priv));
459 
460 	priv->regs = (struct mac_regs *)base_addr;
461 
462 	priv->tx_dq.base = calloc(NUMTXDESC,
463 				sizeof(struct tx_descriptor));
464 	if (priv->tx_dq.base == NULL) {
465 		pr_err("calloc() failed");
466 		goto eth_init_failed_1;
467 	}
468 
469 	priv->tx_sq.base = calloc(NUMTXDESC,
470 				sizeof(struct tx_status));
471 	if (priv->tx_sq.base == NULL) {
472 		pr_err("calloc() failed");
473 		goto eth_init_failed_2;
474 	}
475 
476 	priv->rx_dq.base = calloc(NUMRXDESC,
477 				sizeof(struct rx_descriptor));
478 	if (priv->rx_dq.base == NULL) {
479 		pr_err("calloc() failed");
480 		goto eth_init_failed_3;
481 	}
482 
483 	priv->rx_sq.base = calloc(NUMRXDESC,
484 				sizeof(struct rx_status));
485 	if (priv->rx_sq.base == NULL) {
486 		pr_err("calloc() failed");
487 		goto eth_init_failed_4;
488 	}
489 
490 	dev = malloc(sizeof *dev);
491 	if (dev == NULL) {
492 		pr_err("malloc() failed");
493 		goto eth_init_failed_5;
494 	}
495 	memset(dev, 0, sizeof *dev);
496 
497 	dev->iobase = base_addr;
498 	dev->priv = priv;
499 	dev->init = ep93xx_eth_open;
500 	dev->halt = ep93xx_eth_close;
501 	dev->send = ep93xx_eth_send_packet;
502 	dev->recv = ep93xx_eth_rcv_packet;
503 
504 	sprintf(dev->name, "ep93xx_eth-%hu", dev_num);
505 
506 	eth_register(dev);
507 
508 	/* Done! */
509 	ret = 1;
510 	goto eth_init_done;
511 
512 eth_init_failed_5:
513 	free(priv->rx_sq.base);
514 	/* Fall through */
515 
516 eth_init_failed_4:
517 	free(priv->rx_dq.base);
518 	/* Fall through */
519 
520 eth_init_failed_3:
521 	free(priv->tx_sq.base);
522 	/* Fall through */
523 
524 eth_init_failed_2:
525 	free(priv->tx_dq.base);
526 	/* Fall through */
527 
528 eth_init_failed_1:
529 	free(priv);
530 	/* Fall through */
531 
532 eth_init_failed_0:
533 	/* Fall through */
534 
535 eth_init_done:
536 	debug("-ep93xx_eth_initialize %d", ret);
537 	return ret;
538 }
539 
540 #if defined(CONFIG_MII)
541 
542 /**
543  * Maximum MII address we support
544  */
545 #define MII_ADDRESS_MAX			31
546 
547 /**
548  * Maximum MII register address we support
549  */
550 #define MII_REGISTER_MAX		31
551 
552 /**
553  * Read a 16-bit value from an MII register.
554  */
555 static int ep93xx_miiphy_read(struct mii_dev *bus, int addr, int devad,
556 			      int reg)
557 {
558 	unsigned short value = 0;
559 	struct mac_regs *mac = (struct mac_regs *)MAC_BASE;
560 	int ret = -1;
561 	uint32_t self_ctl;
562 
563 	debug("+ep93xx_miiphy_read");
564 
565 	/* Parameter checks */
566 	BUG_ON(bus->name == NULL);
567 	BUG_ON(addr > MII_ADDRESS_MAX);
568 	BUG_ON(reg > MII_REGISTER_MAX);
569 
570 	/*
571 	 * Save the current SelfCTL register value.  Set MAC to suppress
572 	 * preamble bits.  Wait for any previous MII command to complete
573 	 * before issuing the new command.
574 	 */
575 	self_ctl = readl(&mac->selfctl);
576 #if defined(CONFIG_MII_SUPPRESS_PREAMBLE)
577 	writel(self_ctl & ~(1 << 8), &mac->selfctl);
578 #endif	/* defined(CONFIG_MII_SUPPRESS_PREAMBLE) */
579 
580 	while (readl(&mac->miists) & MIISTS_BUSY)
581 		; /* noop */
582 
583 	/*
584 	 * Issue the MII 'read' command.  Wait for the command to complete.
585 	 * Read the MII data value.
586 	 */
587 	writel(MIICMD_OPCODE_READ | ((uint32_t)addr << 5) | (uint32_t)reg,
588 		&mac->miicmd);
589 	while (readl(&mac->miists) & MIISTS_BUSY)
590 		; /* noop */
591 
592 	value = (unsigned short)readl(&mac->miidata);
593 
594 	/* Restore the saved SelfCTL value and return. */
595 	writel(self_ctl, &mac->selfctl);
596 
597 	ret = 0;
598 	/* Fall through */
599 
600 	debug("-ep93xx_miiphy_read");
601 	if (ret < 0)
602 		return ret;
603 	return value;
604 }
605 
606 /**
607  * Write a 16-bit value to an MII register.
608  */
609 static int ep93xx_miiphy_write(struct mii_dev *bus, int addr, int devad,
610 			       int reg, u16 value)
611 {
612 	struct mac_regs *mac = (struct mac_regs *)MAC_BASE;
613 	int ret = -1;
614 	uint32_t self_ctl;
615 
616 	debug("+ep93xx_miiphy_write");
617 
618 	/* Parameter checks */
619 	BUG_ON(bus->name == NULL);
620 	BUG_ON(addr > MII_ADDRESS_MAX);
621 	BUG_ON(reg > MII_REGISTER_MAX);
622 
623 	/*
624 	 * Save the current SelfCTL register value.  Set MAC to suppress
625 	 * preamble bits.  Wait for any previous MII command to complete
626 	 * before issuing the new command.
627 	 */
628 	self_ctl = readl(&mac->selfctl);
629 #if defined(CONFIG_MII_SUPPRESS_PREAMBLE)
630 	writel(self_ctl & ~(1 << 8), &mac->selfctl);
631 #endif	/* defined(CONFIG_MII_SUPPRESS_PREAMBLE) */
632 
633 	while (readl(&mac->miists) & MIISTS_BUSY)
634 		; /* noop */
635 
636 	/* Issue the MII 'write' command.  Wait for the command to complete. */
637 	writel((uint32_t)value, &mac->miidata);
638 	writel(MIICMD_OPCODE_WRITE | ((uint32_t)addr << 5) | (uint32_t)reg,
639 		&mac->miicmd);
640 	while (readl(&mac->miists) & MIISTS_BUSY)
641 		; /* noop */
642 
643 	/* Restore the saved SelfCTL value and return. */
644 	writel(self_ctl, &mac->selfctl);
645 
646 	ret = 0;
647 	/* Fall through */
648 
649 	debug("-ep93xx_miiphy_write");
650 	return ret;
651 }
652 #endif	/* defined(CONFIG_MII) */
653