xref: /openbmc/u-boot/drivers/net/ep93xx_eth.c (revision 8ee59472)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Cirrus Logic EP93xx ethernet MAC / MII driver.
4  *
5  * Copyright (C) 2010, 2009
6  * Matthias Kaehlcke <matthias@kaehlcke.net>
7  *
8  * Copyright (C) 2004, 2005
9  * Cory T. Tusar, Videon Central, Inc., <ctusar@videon-central.com>
10  *
11  * Based on the original eth.[ch] Cirrus Logic EP93xx Rev D. Ethernet Driver,
12  * which is
13  *
14  * (C) Copyright 2002 2003
15  * Adam Bezanson, Network Audio Technologies, Inc.
16  * <bezanson@netaudiotech.com>
17  */
18 
19 #include <command.h>
20 #include <common.h>
21 #include <asm/arch/ep93xx.h>
22 #include <asm/io.h>
23 #include <malloc.h>
24 #include <miiphy.h>
25 #include <linux/types.h>
26 #include "ep93xx_eth.h"
27 
28 #define GET_PRIV(eth_dev)	((struct ep93xx_priv *)(eth_dev)->priv)
29 #define GET_REGS(eth_dev)	(GET_PRIV(eth_dev)->regs)
30 
31 /* ep93xx_miiphy ops forward declarations */
32 static int ep93xx_miiphy_read(struct mii_dev *bus, int addr, int devad,
33 			      int reg);
34 static int ep93xx_miiphy_write(struct mii_dev *bus, int addr, int devad,
35 			       int reg, u16 value);
36 
37 #if defined(EP93XX_MAC_DEBUG)
38 /**
39  * Dump ep93xx_mac values to the terminal.
40  */
41 static void dump_dev(struct eth_device *dev)
42 {
43 	struct ep93xx_priv *priv = GET_PRIV(dev);
44 	int i;
45 
46 	printf("\ndump_dev()\n");
47 	printf("  rx_dq.base	     %p\n", priv->rx_dq.base);
48 	printf("  rx_dq.current	     %p\n", priv->rx_dq.current);
49 	printf("  rx_dq.end	     %p\n", priv->rx_dq.end);
50 	printf("  rx_sq.base	     %p\n", priv->rx_sq.base);
51 	printf("  rx_sq.current	     %p\n", priv->rx_sq.current);
52 	printf("  rx_sq.end	     %p\n", priv->rx_sq.end);
53 
54 	for (i = 0; i < NUMRXDESC; i++)
55 		printf("  rx_buffer[%2.d]      %p\n", i, net_rx_packets[i]);
56 
57 	printf("  tx_dq.base	     %p\n", priv->tx_dq.base);
58 	printf("  tx_dq.current	     %p\n", priv->tx_dq.current);
59 	printf("  tx_dq.end	     %p\n", priv->tx_dq.end);
60 	printf("  tx_sq.base	     %p\n", priv->tx_sq.base);
61 	printf("  tx_sq.current	     %p\n", priv->tx_sq.current);
62 	printf("  tx_sq.end	     %p\n", priv->tx_sq.end);
63 }
64 
65 /**
66  * Dump all RX status queue entries to the terminal.
67  */
68 static void dump_rx_status_queue(struct eth_device *dev)
69 {
70 	struct ep93xx_priv *priv = GET_PRIV(dev);
71 	int i;
72 
73 	printf("\ndump_rx_status_queue()\n");
74 	printf("  descriptor address	 word1		 word2\n");
75 	for (i = 0; i < NUMRXDESC; i++) {
76 		printf("  [ %p ]	     %08X	 %08X\n",
77 			priv->rx_sq.base + i,
78 			(priv->rx_sq.base + i)->word1,
79 			(priv->rx_sq.base + i)->word2);
80 	}
81 }
82 
83 /**
84  * Dump all RX descriptor queue entries to the terminal.
85  */
86 static void dump_rx_descriptor_queue(struct eth_device *dev)
87 {
88 	struct ep93xx_priv *priv = GET_PRIV(dev);
89 	int i;
90 
91 	printf("\ndump_rx_descriptor_queue()\n");
92 	printf("  descriptor address	 word1		 word2\n");
93 	for (i = 0; i < NUMRXDESC; i++) {
94 		printf("  [ %p ]	     %08X	 %08X\n",
95 			priv->rx_dq.base + i,
96 			(priv->rx_dq.base + i)->word1,
97 			(priv->rx_dq.base + i)->word2);
98 	}
99 }
100 
101 /**
102  * Dump all TX descriptor queue entries to the terminal.
103  */
104 static void dump_tx_descriptor_queue(struct eth_device *dev)
105 {
106 	struct ep93xx_priv *priv = GET_PRIV(dev);
107 	int i;
108 
109 	printf("\ndump_tx_descriptor_queue()\n");
110 	printf("  descriptor address	 word1		 word2\n");
111 	for (i = 0; i < NUMTXDESC; i++) {
112 		printf("  [ %p ]	     %08X	 %08X\n",
113 			priv->tx_dq.base + i,
114 			(priv->tx_dq.base + i)->word1,
115 			(priv->tx_dq.base + i)->word2);
116 	}
117 }
118 
119 /**
120  * Dump all TX status queue entries to the terminal.
121  */
122 static void dump_tx_status_queue(struct eth_device *dev)
123 {
124 	struct ep93xx_priv *priv = GET_PRIV(dev);
125 	int i;
126 
127 	printf("\ndump_tx_status_queue()\n");
128 	printf("  descriptor address	 word1\n");
129 	for (i = 0; i < NUMTXDESC; i++) {
130 		printf("  [ %p ]	     %08X\n",
131 			priv->rx_sq.base + i,
132 			(priv->rx_sq.base + i)->word1);
133 	}
134 }
135 #else
136 #define dump_dev(x)
137 #define dump_rx_descriptor_queue(x)
138 #define dump_rx_status_queue(x)
139 #define dump_tx_descriptor_queue(x)
140 #define dump_tx_status_queue(x)
141 #endif	/* defined(EP93XX_MAC_DEBUG) */
142 
143 /**
144  * Reset the EP93xx MAC by twiddling the soft reset bit and spinning until
145  * it's cleared.
146  */
147 static void ep93xx_mac_reset(struct eth_device *dev)
148 {
149 	struct mac_regs *mac = GET_REGS(dev);
150 	uint32_t value;
151 
152 	debug("+ep93xx_mac_reset");
153 
154 	value = readl(&mac->selfctl);
155 	value |= SELFCTL_RESET;
156 	writel(value, &mac->selfctl);
157 
158 	while (readl(&mac->selfctl) & SELFCTL_RESET)
159 		; /* noop */
160 
161 	debug("-ep93xx_mac_reset");
162 }
163 
164 /* Eth device open */
165 static int ep93xx_eth_open(struct eth_device *dev, bd_t *bd)
166 {
167 	struct ep93xx_priv *priv = GET_PRIV(dev);
168 	struct mac_regs *mac = GET_REGS(dev);
169 	uchar *mac_addr = dev->enetaddr;
170 	int i;
171 
172 	debug("+ep93xx_eth_open");
173 
174 	/* Reset the MAC */
175 	ep93xx_mac_reset(dev);
176 
177 	/* Reset the descriptor queues' current and end address values */
178 	priv->tx_dq.current = priv->tx_dq.base;
179 	priv->tx_dq.end = (priv->tx_dq.base + NUMTXDESC);
180 
181 	priv->tx_sq.current = priv->tx_sq.base;
182 	priv->tx_sq.end = (priv->tx_sq.base + NUMTXDESC);
183 
184 	priv->rx_dq.current = priv->rx_dq.base;
185 	priv->rx_dq.end = (priv->rx_dq.base + NUMRXDESC);
186 
187 	priv->rx_sq.current = priv->rx_sq.base;
188 	priv->rx_sq.end = (priv->rx_sq.base + NUMRXDESC);
189 
190 	/*
191 	 * Set the transmit descriptor and status queues' base address,
192 	 * current address, and length registers.  Set the maximum frame
193 	 * length and threshold. Enable the transmit descriptor processor.
194 	 */
195 	writel((uint32_t)priv->tx_dq.base, &mac->txdq.badd);
196 	writel((uint32_t)priv->tx_dq.base, &mac->txdq.curadd);
197 	writel(sizeof(struct tx_descriptor) * NUMTXDESC, &mac->txdq.blen);
198 
199 	writel((uint32_t)priv->tx_sq.base, &mac->txstsq.badd);
200 	writel((uint32_t)priv->tx_sq.base, &mac->txstsq.curadd);
201 	writel(sizeof(struct tx_status) * NUMTXDESC, &mac->txstsq.blen);
202 
203 	writel(0x00040000, &mac->txdthrshld);
204 	writel(0x00040000, &mac->txststhrshld);
205 
206 	writel((TXSTARTMAX << 0) | (PKTSIZE_ALIGN << 16), &mac->maxfrmlen);
207 	writel(BMCTL_TXEN, &mac->bmctl);
208 
209 	/*
210 	 * Set the receive descriptor and status queues' base address,
211 	 * current address, and length registers.  Enable the receive
212 	 * descriptor processor.
213 	 */
214 	writel((uint32_t)priv->rx_dq.base, &mac->rxdq.badd);
215 	writel((uint32_t)priv->rx_dq.base, &mac->rxdq.curadd);
216 	writel(sizeof(struct rx_descriptor) * NUMRXDESC, &mac->rxdq.blen);
217 
218 	writel((uint32_t)priv->rx_sq.base, &mac->rxstsq.badd);
219 	writel((uint32_t)priv->rx_sq.base, &mac->rxstsq.curadd);
220 	writel(sizeof(struct rx_status) * NUMRXDESC, &mac->rxstsq.blen);
221 
222 	writel(0x00040000, &mac->rxdthrshld);
223 
224 	writel(BMCTL_RXEN, &mac->bmctl);
225 
226 	writel(0x00040000, &mac->rxststhrshld);
227 
228 	/* Wait until the receive descriptor processor is active */
229 	while (!(readl(&mac->bmsts) & BMSTS_RXACT))
230 		; /* noop */
231 
232 	/*
233 	 * Initialize the RX descriptor queue. Clear the TX descriptor queue.
234 	 * Clear the RX and TX status queues. Enqueue the RX descriptor and
235 	 * status entries to the MAC.
236 	 */
237 	for (i = 0; i < NUMRXDESC; i++) {
238 		/* set buffer address */
239 		(priv->rx_dq.base + i)->word1 = (uint32_t)net_rx_packets[i];
240 
241 		/* set buffer length, clear buffer index and NSOF */
242 		(priv->rx_dq.base + i)->word2 = PKTSIZE_ALIGN;
243 	}
244 
245 	memset(priv->tx_dq.base, 0,
246 		(sizeof(struct tx_descriptor) * NUMTXDESC));
247 	memset(priv->rx_sq.base, 0,
248 		(sizeof(struct rx_status) * NUMRXDESC));
249 	memset(priv->tx_sq.base, 0,
250 		(sizeof(struct tx_status) * NUMTXDESC));
251 
252 	writel(NUMRXDESC, &mac->rxdqenq);
253 	writel(NUMRXDESC, &mac->rxstsqenq);
254 
255 	/* Set the primary MAC address */
256 	writel(AFP_IAPRIMARY, &mac->afp);
257 	writel(mac_addr[0] | (mac_addr[1] << 8) |
258 		(mac_addr[2] << 16) | (mac_addr[3] << 24),
259 		&mac->indad);
260 	writel(mac_addr[4] | (mac_addr[5] << 8), &mac->indad_upper);
261 
262 	/* Turn on RX and TX */
263 	writel(RXCTL_IA0 | RXCTL_BA | RXCTL_SRXON |
264 		RXCTL_RCRCA | RXCTL_MA, &mac->rxctl);
265 	writel(TXCTL_STXON, &mac->txctl);
266 
267 	/* Dump data structures if we're debugging */
268 	dump_dev(dev);
269 	dump_rx_descriptor_queue(dev);
270 	dump_rx_status_queue(dev);
271 	dump_tx_descriptor_queue(dev);
272 	dump_tx_status_queue(dev);
273 
274 	debug("-ep93xx_eth_open");
275 
276 	return 1;
277 }
278 
279 /**
280  * Halt EP93xx MAC transmit and receive by clearing the TxCTL and RxCTL
281  * registers.
282  */
283 static void ep93xx_eth_close(struct eth_device *dev)
284 {
285 	struct mac_regs *mac = GET_REGS(dev);
286 
287 	debug("+ep93xx_eth_close");
288 
289 	writel(0x00000000, &mac->rxctl);
290 	writel(0x00000000, &mac->txctl);
291 
292 	debug("-ep93xx_eth_close");
293 }
294 
295 /**
296  * Copy a frame of data from the MAC into the protocol layer for further
297  * processing.
298  */
299 static int ep93xx_eth_rcv_packet(struct eth_device *dev)
300 {
301 	struct mac_regs *mac = GET_REGS(dev);
302 	struct ep93xx_priv *priv = GET_PRIV(dev);
303 	int len = -1;
304 
305 	debug("+ep93xx_eth_rcv_packet");
306 
307 	if (RX_STATUS_RFP(priv->rx_sq.current)) {
308 		if (RX_STATUS_RWE(priv->rx_sq.current)) {
309 			/*
310 			 * We have a good frame. Extract the frame's length
311 			 * from the current rx_status_queue entry, and copy
312 			 * the frame's data into net_rx_packets[] of the
313 			 * protocol stack. We track the total number of
314 			 * bytes in the frame (nbytes_frame) which will be
315 			 * used when we pass the data off to the protocol
316 			 * layer via net_process_received_packet().
317 			 */
318 			len = RX_STATUS_FRAME_LEN(priv->rx_sq.current);
319 
320 			net_process_received_packet(
321 				(uchar *)priv->rx_dq.current->word1, len);
322 
323 			debug("reporting %d bytes...\n", len);
324 		} else {
325 			/* Do we have an erroneous packet? */
326 			pr_err("packet rx error, status %08X %08X",
327 				priv->rx_sq.current->word1,
328 				priv->rx_sq.current->word2);
329 			dump_rx_descriptor_queue(dev);
330 			dump_rx_status_queue(dev);
331 		}
332 
333 		/*
334 		 * Clear the associated status queue entry, and
335 		 * increment our current pointers to the next RX
336 		 * descriptor and status queue entries (making sure
337 		 * we wrap properly).
338 		 */
339 		memset((void *)priv->rx_sq.current, 0,
340 			sizeof(struct rx_status));
341 
342 		priv->rx_sq.current++;
343 		if (priv->rx_sq.current >= priv->rx_sq.end)
344 			priv->rx_sq.current = priv->rx_sq.base;
345 
346 		priv->rx_dq.current++;
347 		if (priv->rx_dq.current >= priv->rx_dq.end)
348 			priv->rx_dq.current = priv->rx_dq.base;
349 
350 		/*
351 		 * Finally, return the RX descriptor and status entries
352 		 * back to the MAC engine, and loop again, checking for
353 		 * more descriptors to process.
354 		 */
355 		writel(1, &mac->rxdqenq);
356 		writel(1, &mac->rxstsqenq);
357 	} else {
358 		len = 0;
359 	}
360 
361 	debug("-ep93xx_eth_rcv_packet %d", len);
362 	return len;
363 }
364 
365 /**
366  * Send a block of data via ethernet.
367  */
368 static int ep93xx_eth_send_packet(struct eth_device *dev,
369 				void * const packet, int const length)
370 {
371 	struct mac_regs *mac = GET_REGS(dev);
372 	struct ep93xx_priv *priv = GET_PRIV(dev);
373 	int ret = -1;
374 
375 	debug("+ep93xx_eth_send_packet");
376 
377 	/* Parameter check */
378 	BUG_ON(packet == NULL);
379 
380 	/*
381 	 * Initialize the TX descriptor queue with the new packet's info.
382 	 * Clear the associated status queue entry. Enqueue the packet
383 	 * to the MAC for transmission.
384 	 */
385 
386 	/* set buffer address */
387 	priv->tx_dq.current->word1 = (uint32_t)packet;
388 
389 	/* set buffer length and EOF bit */
390 	priv->tx_dq.current->word2 = length | TX_DESC_EOF;
391 
392 	/* clear tx status */
393 	priv->tx_sq.current->word1 = 0;
394 
395 	/* enqueue the TX descriptor */
396 	writel(1, &mac->txdqenq);
397 
398 	/* wait for the frame to become processed */
399 	while (!TX_STATUS_TXFP(priv->tx_sq.current))
400 		; /* noop */
401 
402 	if (!TX_STATUS_TXWE(priv->tx_sq.current)) {
403 		pr_err("packet tx error, status %08X",
404 			priv->tx_sq.current->word1);
405 		dump_tx_descriptor_queue(dev);
406 		dump_tx_status_queue(dev);
407 
408 		/* TODO: Add better error handling? */
409 		goto eth_send_out;
410 	}
411 
412 	ret = 0;
413 	/* Fall through */
414 
415 eth_send_out:
416 	debug("-ep93xx_eth_send_packet %d", ret);
417 	return ret;
418 }
419 
420 #if defined(CONFIG_MII)
421 int ep93xx_miiphy_initialize(bd_t * const bd)
422 {
423 	int retval;
424 	struct mii_dev *mdiodev = mdio_alloc();
425 	if (!mdiodev)
426 		return -ENOMEM;
427 	strncpy(mdiodev->name, "ep93xx_eth0", MDIO_NAME_LEN);
428 	mdiodev->read = ep93xx_miiphy_read;
429 	mdiodev->write = ep93xx_miiphy_write;
430 
431 	retval = mdio_register(mdiodev);
432 	if (retval < 0)
433 		return retval;
434 	return 0;
435 }
436 #endif
437 
438 /**
439  * Initialize the EP93xx MAC.  The MAC hardware is reset.  Buffers are
440  * allocated, if necessary, for the TX and RX descriptor and status queues,
441  * as well as for received packets.  The EP93XX MAC hardware is initialized.
442  * Transmit and receive operations are enabled.
443  */
444 int ep93xx_eth_initialize(u8 dev_num, int base_addr)
445 {
446 	int ret = -1;
447 	struct eth_device *dev;
448 	struct ep93xx_priv *priv;
449 
450 	debug("+ep93xx_eth_initialize");
451 
452 	priv = malloc(sizeof(*priv));
453 	if (!priv) {
454 		pr_err("malloc() failed");
455 		goto eth_init_failed_0;
456 	}
457 	memset(priv, 0, sizeof(*priv));
458 
459 	priv->regs = (struct mac_regs *)base_addr;
460 
461 	priv->tx_dq.base = calloc(NUMTXDESC,
462 				sizeof(struct tx_descriptor));
463 	if (priv->tx_dq.base == NULL) {
464 		pr_err("calloc() failed");
465 		goto eth_init_failed_1;
466 	}
467 
468 	priv->tx_sq.base = calloc(NUMTXDESC,
469 				sizeof(struct tx_status));
470 	if (priv->tx_sq.base == NULL) {
471 		pr_err("calloc() failed");
472 		goto eth_init_failed_2;
473 	}
474 
475 	priv->rx_dq.base = calloc(NUMRXDESC,
476 				sizeof(struct rx_descriptor));
477 	if (priv->rx_dq.base == NULL) {
478 		pr_err("calloc() failed");
479 		goto eth_init_failed_3;
480 	}
481 
482 	priv->rx_sq.base = calloc(NUMRXDESC,
483 				sizeof(struct rx_status));
484 	if (priv->rx_sq.base == NULL) {
485 		pr_err("calloc() failed");
486 		goto eth_init_failed_4;
487 	}
488 
489 	dev = malloc(sizeof *dev);
490 	if (dev == NULL) {
491 		pr_err("malloc() failed");
492 		goto eth_init_failed_5;
493 	}
494 	memset(dev, 0, sizeof *dev);
495 
496 	dev->iobase = base_addr;
497 	dev->priv = priv;
498 	dev->init = ep93xx_eth_open;
499 	dev->halt = ep93xx_eth_close;
500 	dev->send = ep93xx_eth_send_packet;
501 	dev->recv = ep93xx_eth_rcv_packet;
502 
503 	sprintf(dev->name, "ep93xx_eth-%hu", dev_num);
504 
505 	eth_register(dev);
506 
507 	/* Done! */
508 	ret = 1;
509 	goto eth_init_done;
510 
511 eth_init_failed_5:
512 	free(priv->rx_sq.base);
513 	/* Fall through */
514 
515 eth_init_failed_4:
516 	free(priv->rx_dq.base);
517 	/* Fall through */
518 
519 eth_init_failed_3:
520 	free(priv->tx_sq.base);
521 	/* Fall through */
522 
523 eth_init_failed_2:
524 	free(priv->tx_dq.base);
525 	/* Fall through */
526 
527 eth_init_failed_1:
528 	free(priv);
529 	/* Fall through */
530 
531 eth_init_failed_0:
532 	/* Fall through */
533 
534 eth_init_done:
535 	debug("-ep93xx_eth_initialize %d", ret);
536 	return ret;
537 }
538 
539 #if defined(CONFIG_MII)
540 
541 /**
542  * Maximum MII address we support
543  */
544 #define MII_ADDRESS_MAX			31
545 
546 /**
547  * Maximum MII register address we support
548  */
549 #define MII_REGISTER_MAX		31
550 
551 /**
552  * Read a 16-bit value from an MII register.
553  */
554 static int ep93xx_miiphy_read(struct mii_dev *bus, int addr, int devad,
555 			      int reg)
556 {
557 	unsigned short value = 0;
558 	struct mac_regs *mac = (struct mac_regs *)MAC_BASE;
559 	int ret = -1;
560 	uint32_t self_ctl;
561 
562 	debug("+ep93xx_miiphy_read");
563 
564 	/* Parameter checks */
565 	BUG_ON(bus->name == NULL);
566 	BUG_ON(addr > MII_ADDRESS_MAX);
567 	BUG_ON(reg > MII_REGISTER_MAX);
568 
569 	/*
570 	 * Save the current SelfCTL register value.  Set MAC to suppress
571 	 * preamble bits.  Wait for any previous MII command to complete
572 	 * before issuing the new command.
573 	 */
574 	self_ctl = readl(&mac->selfctl);
575 #if defined(CONFIG_MII_SUPPRESS_PREAMBLE)
576 	writel(self_ctl & ~(1 << 8), &mac->selfctl);
577 #endif	/* defined(CONFIG_MII_SUPPRESS_PREAMBLE) */
578 
579 	while (readl(&mac->miists) & MIISTS_BUSY)
580 		; /* noop */
581 
582 	/*
583 	 * Issue the MII 'read' command.  Wait for the command to complete.
584 	 * Read the MII data value.
585 	 */
586 	writel(MIICMD_OPCODE_READ | ((uint32_t)addr << 5) | (uint32_t)reg,
587 		&mac->miicmd);
588 	while (readl(&mac->miists) & MIISTS_BUSY)
589 		; /* noop */
590 
591 	value = (unsigned short)readl(&mac->miidata);
592 
593 	/* Restore the saved SelfCTL value and return. */
594 	writel(self_ctl, &mac->selfctl);
595 
596 	ret = 0;
597 	/* Fall through */
598 
599 	debug("-ep93xx_miiphy_read");
600 	if (ret < 0)
601 		return ret;
602 	return value;
603 }
604 
605 /**
606  * Write a 16-bit value to an MII register.
607  */
608 static int ep93xx_miiphy_write(struct mii_dev *bus, int addr, int devad,
609 			       int reg, u16 value)
610 {
611 	struct mac_regs *mac = (struct mac_regs *)MAC_BASE;
612 	int ret = -1;
613 	uint32_t self_ctl;
614 
615 	debug("+ep93xx_miiphy_write");
616 
617 	/* Parameter checks */
618 	BUG_ON(bus->name == NULL);
619 	BUG_ON(addr > MII_ADDRESS_MAX);
620 	BUG_ON(reg > MII_REGISTER_MAX);
621 
622 	/*
623 	 * Save the current SelfCTL register value.  Set MAC to suppress
624 	 * preamble bits.  Wait for any previous MII command to complete
625 	 * before issuing the new command.
626 	 */
627 	self_ctl = readl(&mac->selfctl);
628 #if defined(CONFIG_MII_SUPPRESS_PREAMBLE)
629 	writel(self_ctl & ~(1 << 8), &mac->selfctl);
630 #endif	/* defined(CONFIG_MII_SUPPRESS_PREAMBLE) */
631 
632 	while (readl(&mac->miists) & MIISTS_BUSY)
633 		; /* noop */
634 
635 	/* Issue the MII 'write' command.  Wait for the command to complete. */
636 	writel((uint32_t)value, &mac->miidata);
637 	writel(MIICMD_OPCODE_WRITE | ((uint32_t)addr << 5) | (uint32_t)reg,
638 		&mac->miicmd);
639 	while (readl(&mac->miists) & MIISTS_BUSY)
640 		; /* noop */
641 
642 	/* Restore the saved SelfCTL value and return. */
643 	writel(self_ctl, &mac->selfctl);
644 
645 	ret = 0;
646 	/* Fall through */
647 
648 	debug("-ep93xx_miiphy_write");
649 	return ret;
650 }
651 #endif	/* defined(CONFIG_MII) */
652