1 /***********************license start***************
2  * Author: Cavium Networks
3  *
4  * Contact: support@caviumnetworks.com
5  * This file is part of the OCTEON SDK
6  *
7  * Copyright (c) 2003-2008 Cavium Networks
8  *
9  * This file is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License, Version 2, as
11  * published by the Free Software Foundation.
12  *
13  * This file is distributed in the hope that it will be useful, but
14  * AS-IS and WITHOUT ANY WARRANTY; without even the implied warranty
15  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, TITLE, or
16  * NONINFRINGEMENT.  See the GNU General Public License for more
17  * details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this file; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22  * or visit http://www.gnu.org/licenses/.
23  *
24  * This file may also be available under a different license from Cavium.
25  * Contact Cavium Networks for more information
26  ***********************license end**************************************/
27 
28 /*
29  * Functions for SGMII initialization, configuration,
30  * and monitoring.
31  */
32 
33 #include <asm/octeon/octeon.h>
34 
35 #include <asm/octeon/cvmx-config.h>
36 
37 #include <asm/octeon/cvmx-mdio.h>
38 #include <asm/octeon/cvmx-helper.h>
39 #include <asm/octeon/cvmx-helper-board.h>
40 
41 #include <asm/octeon/cvmx-gmxx-defs.h>
42 #include <asm/octeon/cvmx-pcsx-defs.h>
43 
44 void __cvmx_interrupt_gmxx_enable(int interface);
45 void __cvmx_interrupt_pcsx_intx_en_reg_enable(int index, int block);
46 void __cvmx_interrupt_pcsxx_int_en_reg_enable(int index);
47 
48 /**
49  * Perform initialization required only once for an SGMII port.
50  *
51  * @interface: Interface to init
52  * @index:     Index of prot on the interface
53  *
54  * Returns Zero on success, negative on failure
55  */
56 static int __cvmx_helper_sgmii_hardware_init_one_time(int interface, int index)
57 {
58 	const uint64_t clock_mhz = cvmx_sysinfo_get()->cpu_clock_hz / 1000000;
59 	union cvmx_pcsx_miscx_ctl_reg pcs_misc_ctl_reg;
60 	union cvmx_pcsx_linkx_timer_count_reg pcsx_linkx_timer_count_reg;
61 	union cvmx_gmxx_prtx_cfg gmxx_prtx_cfg;
62 
63 	/* Disable GMX */
64 	gmxx_prtx_cfg.u64 = cvmx_read_csr(CVMX_GMXX_PRTX_CFG(index, interface));
65 	gmxx_prtx_cfg.s.en = 0;
66 	cvmx_write_csr(CVMX_GMXX_PRTX_CFG(index, interface), gmxx_prtx_cfg.u64);
67 
68 	/*
69 	 * Write PCS*_LINK*_TIMER_COUNT_REG[COUNT] with the
70 	 * appropriate value. 1000BASE-X specifies a 10ms
71 	 * interval. SGMII specifies a 1.6ms interval.
72 	 */
73 	pcs_misc_ctl_reg.u64 =
74 	    cvmx_read_csr(CVMX_PCSX_MISCX_CTL_REG(index, interface));
75 	pcsx_linkx_timer_count_reg.u64 =
76 	    cvmx_read_csr(CVMX_PCSX_LINKX_TIMER_COUNT_REG(index, interface));
77 	if (pcs_misc_ctl_reg.s.mode) {
78 		/* 1000BASE-X */
79 		pcsx_linkx_timer_count_reg.s.count =
80 		    (10000ull * clock_mhz) >> 10;
81 	} else {
82 		/* SGMII */
83 		pcsx_linkx_timer_count_reg.s.count =
84 		    (1600ull * clock_mhz) >> 10;
85 	}
86 	cvmx_write_csr(CVMX_PCSX_LINKX_TIMER_COUNT_REG(index, interface),
87 		       pcsx_linkx_timer_count_reg.u64);
88 
89 	/*
90 	 * Write the advertisement register to be used as the
91 	 * tx_Config_Reg<D15:D0> of the autonegotiation.  In
92 	 * 1000BASE-X mode, tx_Config_Reg<D15:D0> is PCS*_AN*_ADV_REG.
93 	 * In SGMII PHY mode, tx_Config_Reg<D15:D0> is
94 	 * PCS*_SGM*_AN_ADV_REG.  In SGMII MAC mode,
95 	 * tx_Config_Reg<D15:D0> is the fixed value 0x4001, so this
96 	 * step can be skipped.
97 	 */
98 	if (pcs_misc_ctl_reg.s.mode) {
99 		/* 1000BASE-X */
100 		union cvmx_pcsx_anx_adv_reg pcsx_anx_adv_reg;
101 		pcsx_anx_adv_reg.u64 =
102 		    cvmx_read_csr(CVMX_PCSX_ANX_ADV_REG(index, interface));
103 		pcsx_anx_adv_reg.s.rem_flt = 0;
104 		pcsx_anx_adv_reg.s.pause = 3;
105 		pcsx_anx_adv_reg.s.hfd = 1;
106 		pcsx_anx_adv_reg.s.fd = 1;
107 		cvmx_write_csr(CVMX_PCSX_ANX_ADV_REG(index, interface),
108 			       pcsx_anx_adv_reg.u64);
109 	} else {
110 		union cvmx_pcsx_miscx_ctl_reg pcsx_miscx_ctl_reg;
111 		pcsx_miscx_ctl_reg.u64 =
112 		    cvmx_read_csr(CVMX_PCSX_MISCX_CTL_REG(index, interface));
113 		if (pcsx_miscx_ctl_reg.s.mac_phy) {
114 			/* PHY Mode */
115 			union cvmx_pcsx_sgmx_an_adv_reg pcsx_sgmx_an_adv_reg;
116 			pcsx_sgmx_an_adv_reg.u64 =
117 			    cvmx_read_csr(CVMX_PCSX_SGMX_AN_ADV_REG
118 					  (index, interface));
119 			pcsx_sgmx_an_adv_reg.s.link = 1;
120 			pcsx_sgmx_an_adv_reg.s.dup = 1;
121 			pcsx_sgmx_an_adv_reg.s.speed = 2;
122 			cvmx_write_csr(CVMX_PCSX_SGMX_AN_ADV_REG
123 				       (index, interface),
124 				       pcsx_sgmx_an_adv_reg.u64);
125 		} else {
126 			/* MAC Mode - Nothing to do */
127 		}
128 	}
129 	return 0;
130 }
131 
132 /**
133  * Initialize the SERTES link for the first time or after a loss
134  * of link.
135  *
136  * @interface: Interface to init
137  * @index:     Index of prot on the interface
138  *
139  * Returns Zero on success, negative on failure
140  */
141 static int __cvmx_helper_sgmii_hardware_init_link(int interface, int index)
142 {
143 	union cvmx_pcsx_mrx_control_reg control_reg;
144 
145 	/*
146 	 * Take PCS through a reset sequence.
147 	 * PCS*_MR*_CONTROL_REG[PWR_DN] should be cleared to zero.
148 	 * Write PCS*_MR*_CONTROL_REG[RESET]=1 (while not changing the
149 	 * value of the other PCS*_MR*_CONTROL_REG bits).  Read
150 	 * PCS*_MR*_CONTROL_REG[RESET] until it changes value to
151 	 * zero.
152 	 */
153 	control_reg.u64 =
154 	    cvmx_read_csr(CVMX_PCSX_MRX_CONTROL_REG(index, interface));
155 	if (cvmx_sysinfo_get()->board_type != CVMX_BOARD_TYPE_SIM) {
156 		control_reg.s.reset = 1;
157 		cvmx_write_csr(CVMX_PCSX_MRX_CONTROL_REG(index, interface),
158 			       control_reg.u64);
159 		if (CVMX_WAIT_FOR_FIELD64
160 		    (CVMX_PCSX_MRX_CONTROL_REG(index, interface),
161 		     union cvmx_pcsx_mrx_control_reg, reset, ==, 0, 10000)) {
162 			cvmx_dprintf("SGMII%d: Timeout waiting for port %d "
163 				     "to finish reset\n",
164 			     interface, index);
165 			return -1;
166 		}
167 	}
168 
169 	/*
170 	 * Write PCS*_MR*_CONTROL_REG[RST_AN]=1 to ensure a fresh
171 	 * sgmii negotiation starts.
172 	 */
173 	control_reg.s.rst_an = 1;
174 	control_reg.s.an_en = 1;
175 	control_reg.s.pwr_dn = 0;
176 	cvmx_write_csr(CVMX_PCSX_MRX_CONTROL_REG(index, interface),
177 		       control_reg.u64);
178 
179 	/*
180 	 * Wait for PCS*_MR*_STATUS_REG[AN_CPT] to be set, indicating
181 	 * that sgmii autonegotiation is complete. In MAC mode this
182 	 * isn't an ethernet link, but a link between Octeon and the
183 	 * PHY.
184 	 */
185 	if ((cvmx_sysinfo_get()->board_type != CVMX_BOARD_TYPE_SIM) &&
186 	    CVMX_WAIT_FOR_FIELD64(CVMX_PCSX_MRX_STATUS_REG(index, interface),
187 				  union cvmx_pcsx_mrx_status_reg, an_cpt, ==, 1,
188 				  10000)) {
189 		/* cvmx_dprintf("SGMII%d: Port %d link timeout\n", interface, index); */
190 		return -1;
191 	}
192 	return 0;
193 }
194 
195 /**
196  * Configure an SGMII link to the specified speed after the SERTES
197  * link is up.
198  *
199  * @interface: Interface to init
200  * @index:     Index of prot on the interface
201  * @link_info: Link state to configure
202  *
203  * Returns Zero on success, negative on failure
204  */
205 static int __cvmx_helper_sgmii_hardware_init_link_speed(int interface,
206 							int index,
207 							cvmx_helper_link_info_t
208 							link_info)
209 {
210 	int is_enabled;
211 	union cvmx_gmxx_prtx_cfg gmxx_prtx_cfg;
212 	union cvmx_pcsx_miscx_ctl_reg pcsx_miscx_ctl_reg;
213 
214 	/* Disable GMX before we make any changes. Remember the enable state */
215 	gmxx_prtx_cfg.u64 = cvmx_read_csr(CVMX_GMXX_PRTX_CFG(index, interface));
216 	is_enabled = gmxx_prtx_cfg.s.en;
217 	gmxx_prtx_cfg.s.en = 0;
218 	cvmx_write_csr(CVMX_GMXX_PRTX_CFG(index, interface), gmxx_prtx_cfg.u64);
219 
220 	/* Wait for GMX to be idle */
221 	if (CVMX_WAIT_FOR_FIELD64
222 	    (CVMX_GMXX_PRTX_CFG(index, interface), union cvmx_gmxx_prtx_cfg,
223 	     rx_idle, ==, 1, 10000)
224 	    || CVMX_WAIT_FOR_FIELD64(CVMX_GMXX_PRTX_CFG(index, interface),
225 				     union cvmx_gmxx_prtx_cfg, tx_idle, ==, 1,
226 				     10000)) {
227 		cvmx_dprintf
228 		    ("SGMII%d: Timeout waiting for port %d to be idle\n",
229 		     interface, index);
230 		return -1;
231 	}
232 
233 	/* Read GMX CFG again to make sure the disable completed */
234 	gmxx_prtx_cfg.u64 = cvmx_read_csr(CVMX_GMXX_PRTX_CFG(index, interface));
235 
236 	/*
237 	 * Get the misc control for PCS. We will need to set the
238 	 * duplication amount.
239 	 */
240 	pcsx_miscx_ctl_reg.u64 =
241 	    cvmx_read_csr(CVMX_PCSX_MISCX_CTL_REG(index, interface));
242 
243 	/*
244 	 * Use GMXENO to force the link down if the status we get says
245 	 * it should be down.
246 	 */
247 	pcsx_miscx_ctl_reg.s.gmxeno = !link_info.s.link_up;
248 
249 	/* Only change the duplex setting if the link is up */
250 	if (link_info.s.link_up)
251 		gmxx_prtx_cfg.s.duplex = link_info.s.full_duplex;
252 
253 	/* Do speed based setting for GMX */
254 	switch (link_info.s.speed) {
255 	case 10:
256 		gmxx_prtx_cfg.s.speed = 0;
257 		gmxx_prtx_cfg.s.speed_msb = 1;
258 		gmxx_prtx_cfg.s.slottime = 0;
259 		/* Setting from GMX-603 */
260 		pcsx_miscx_ctl_reg.s.samp_pt = 25;
261 		cvmx_write_csr(CVMX_GMXX_TXX_SLOT(index, interface), 64);
262 		cvmx_write_csr(CVMX_GMXX_TXX_BURST(index, interface), 0);
263 		break;
264 	case 100:
265 		gmxx_prtx_cfg.s.speed = 0;
266 		gmxx_prtx_cfg.s.speed_msb = 0;
267 		gmxx_prtx_cfg.s.slottime = 0;
268 		pcsx_miscx_ctl_reg.s.samp_pt = 0x5;
269 		cvmx_write_csr(CVMX_GMXX_TXX_SLOT(index, interface), 64);
270 		cvmx_write_csr(CVMX_GMXX_TXX_BURST(index, interface), 0);
271 		break;
272 	case 1000:
273 		gmxx_prtx_cfg.s.speed = 1;
274 		gmxx_prtx_cfg.s.speed_msb = 0;
275 		gmxx_prtx_cfg.s.slottime = 1;
276 		pcsx_miscx_ctl_reg.s.samp_pt = 1;
277 		cvmx_write_csr(CVMX_GMXX_TXX_SLOT(index, interface), 512);
278 		cvmx_write_csr(CVMX_GMXX_TXX_BURST(index, interface), 8192);
279 		break;
280 	default:
281 		break;
282 	}
283 
284 	/* Write the new misc control for PCS */
285 	cvmx_write_csr(CVMX_PCSX_MISCX_CTL_REG(index, interface),
286 		       pcsx_miscx_ctl_reg.u64);
287 
288 	/* Write the new GMX settings with the port still disabled */
289 	cvmx_write_csr(CVMX_GMXX_PRTX_CFG(index, interface), gmxx_prtx_cfg.u64);
290 
291 	/* Read GMX CFG again to make sure the config completed */
292 	gmxx_prtx_cfg.u64 = cvmx_read_csr(CVMX_GMXX_PRTX_CFG(index, interface));
293 
294 	/* Restore the enabled / disabled state */
295 	gmxx_prtx_cfg.s.en = is_enabled;
296 	cvmx_write_csr(CVMX_GMXX_PRTX_CFG(index, interface), gmxx_prtx_cfg.u64);
297 
298 	return 0;
299 }
300 
301 /**
302  * Bring up the SGMII interface to be ready for packet I/O but
303  * leave I/O disabled using the GMX override. This function
304  * follows the bringup documented in 10.6.3 of the manual.
305  *
306  * @interface: Interface to bringup
307  * @num_ports: Number of ports on the interface
308  *
309  * Returns Zero on success, negative on failure
310  */
311 static int __cvmx_helper_sgmii_hardware_init(int interface, int num_ports)
312 {
313 	int index;
314 
315 	__cvmx_helper_setup_gmx(interface, num_ports);
316 
317 	for (index = 0; index < num_ports; index++) {
318 		int ipd_port = cvmx_helper_get_ipd_port(interface, index);
319 		__cvmx_helper_sgmii_hardware_init_one_time(interface, index);
320 		/* Linux kernel driver will call ....link_set with the
321 		 * proper link state. In the simulator there is no
322 		 * link state polling and hence it is set from
323 		 * here.
324 		 */
325 		if (cvmx_sysinfo_get()->board_type == CVMX_BOARD_TYPE_SIM)
326 			__cvmx_helper_sgmii_link_set(ipd_port,
327 				       __cvmx_helper_sgmii_link_get(ipd_port));
328 	}
329 
330 	return 0;
331 }
332 
333 int __cvmx_helper_sgmii_enumerate(int interface)
334 {
335 	return 4;
336 }
337 /**
338  * Probe a SGMII interface and determine the number of ports
339  * connected to it. The SGMII interface should still be down after
340  * this call.
341  *
342  * @interface: Interface to probe
343  *
344  * Returns Number of ports on the interface. Zero to disable.
345  */
346 int __cvmx_helper_sgmii_probe(int interface)
347 {
348 	union cvmx_gmxx_inf_mode mode;
349 
350 	/*
351 	 * Due to errata GMX-700 on CN56XXp1.x and CN52XXp1.x, the
352 	 * interface needs to be enabled before IPD otherwise per port
353 	 * backpressure may not work properly
354 	 */
355 	mode.u64 = cvmx_read_csr(CVMX_GMXX_INF_MODE(interface));
356 	mode.s.en = 1;
357 	cvmx_write_csr(CVMX_GMXX_INF_MODE(interface), mode.u64);
358 	return __cvmx_helper_sgmii_enumerate(interface);
359 }
360 
361 /**
362  * Bringup and enable a SGMII interface. After this call packet
363  * I/O should be fully functional. This is called with IPD
364  * enabled but PKO disabled.
365  *
366  * @interface: Interface to bring up
367  *
368  * Returns Zero on success, negative on failure
369  */
370 int __cvmx_helper_sgmii_enable(int interface)
371 {
372 	int num_ports = cvmx_helper_ports_on_interface(interface);
373 	int index;
374 
375 	__cvmx_helper_sgmii_hardware_init(interface, num_ports);
376 
377 	for (index = 0; index < num_ports; index++) {
378 		union cvmx_gmxx_prtx_cfg gmxx_prtx_cfg;
379 		gmxx_prtx_cfg.u64 =
380 		    cvmx_read_csr(CVMX_GMXX_PRTX_CFG(index, interface));
381 		gmxx_prtx_cfg.s.en = 1;
382 		cvmx_write_csr(CVMX_GMXX_PRTX_CFG(index, interface),
383 			       gmxx_prtx_cfg.u64);
384 		__cvmx_interrupt_pcsx_intx_en_reg_enable(index, interface);
385 	}
386 	__cvmx_interrupt_pcsxx_int_en_reg_enable(interface);
387 	__cvmx_interrupt_gmxx_enable(interface);
388 	return 0;
389 }
390 
391 /**
392  * Return the link state of an IPD/PKO port as returned by
393  * auto negotiation. The result of this function may not match
394  * Octeon's link config if auto negotiation has changed since
395  * the last call to cvmx_helper_link_set().
396  *
397  * @ipd_port: IPD/PKO port to query
398  *
399  * Returns Link state
400  */
401 cvmx_helper_link_info_t __cvmx_helper_sgmii_link_get(int ipd_port)
402 {
403 	cvmx_helper_link_info_t result;
404 	union cvmx_pcsx_miscx_ctl_reg pcs_misc_ctl_reg;
405 	int interface = cvmx_helper_get_interface_num(ipd_port);
406 	int index = cvmx_helper_get_interface_index_num(ipd_port);
407 	union cvmx_pcsx_mrx_control_reg pcsx_mrx_control_reg;
408 
409 	result.u64 = 0;
410 
411 	if (cvmx_sysinfo_get()->board_type == CVMX_BOARD_TYPE_SIM) {
412 		/* The simulator gives you a simulated 1Gbps full duplex link */
413 		result.s.link_up = 1;
414 		result.s.full_duplex = 1;
415 		result.s.speed = 1000;
416 		return result;
417 	}
418 
419 	pcsx_mrx_control_reg.u64 =
420 	    cvmx_read_csr(CVMX_PCSX_MRX_CONTROL_REG(index, interface));
421 	if (pcsx_mrx_control_reg.s.loopbck1) {
422 		/* Force 1Gbps full duplex link for internal loopback */
423 		result.s.link_up = 1;
424 		result.s.full_duplex = 1;
425 		result.s.speed = 1000;
426 		return result;
427 	}
428 
429 	pcs_misc_ctl_reg.u64 =
430 	    cvmx_read_csr(CVMX_PCSX_MISCX_CTL_REG(index, interface));
431 	if (pcs_misc_ctl_reg.s.mode) {
432 		/* 1000BASE-X */
433 		/* FIXME */
434 	} else {
435 		union cvmx_pcsx_miscx_ctl_reg pcsx_miscx_ctl_reg;
436 		pcsx_miscx_ctl_reg.u64 =
437 		    cvmx_read_csr(CVMX_PCSX_MISCX_CTL_REG(index, interface));
438 		if (pcsx_miscx_ctl_reg.s.mac_phy) {
439 			/* PHY Mode */
440 			union cvmx_pcsx_mrx_status_reg pcsx_mrx_status_reg;
441 			union cvmx_pcsx_anx_results_reg pcsx_anx_results_reg;
442 
443 			/*
444 			 * Don't bother continuing if the SERTES low
445 			 * level link is down
446 			 */
447 			pcsx_mrx_status_reg.u64 =
448 			    cvmx_read_csr(CVMX_PCSX_MRX_STATUS_REG
449 					  (index, interface));
450 			if (pcsx_mrx_status_reg.s.lnk_st == 0) {
451 				if (__cvmx_helper_sgmii_hardware_init_link
452 				    (interface, index) != 0)
453 					return result;
454 			}
455 
456 			/* Read the autoneg results */
457 			pcsx_anx_results_reg.u64 =
458 			    cvmx_read_csr(CVMX_PCSX_ANX_RESULTS_REG
459 					  (index, interface));
460 			if (pcsx_anx_results_reg.s.an_cpt) {
461 				/*
462 				 * Auto negotiation is complete. Set
463 				 * status accordingly.
464 				 */
465 				result.s.full_duplex =
466 				    pcsx_anx_results_reg.s.dup;
467 				result.s.link_up =
468 				    pcsx_anx_results_reg.s.link_ok;
469 				switch (pcsx_anx_results_reg.s.spd) {
470 				case 0:
471 					result.s.speed = 10;
472 					break;
473 				case 1:
474 					result.s.speed = 100;
475 					break;
476 				case 2:
477 					result.s.speed = 1000;
478 					break;
479 				default:
480 					result.s.speed = 0;
481 					result.s.link_up = 0;
482 					break;
483 				}
484 			} else {
485 				/*
486 				 * Auto negotiation isn't
487 				 * complete. Return link down.
488 				 */
489 				result.s.speed = 0;
490 				result.s.link_up = 0;
491 			}
492 		} else {	/* MAC Mode */
493 
494 			result = __cvmx_helper_board_link_get(ipd_port);
495 		}
496 	}
497 	return result;
498 }
499 
500 /**
501  * Configure an IPD/PKO port for the specified link state. This
502  * function does not influence auto negotiation at the PHY level.
503  * The passed link state must always match the link state returned
504  * by cvmx_helper_link_get(). It is normally best to use
505  * cvmx_helper_link_autoconf() instead.
506  *
507  * @ipd_port:  IPD/PKO port to configure
508  * @link_info: The new link state
509  *
510  * Returns Zero on success, negative on failure
511  */
512 int __cvmx_helper_sgmii_link_set(int ipd_port,
513 				 cvmx_helper_link_info_t link_info)
514 {
515 	int interface = cvmx_helper_get_interface_num(ipd_port);
516 	int index = cvmx_helper_get_interface_index_num(ipd_port);
517 	__cvmx_helper_sgmii_hardware_init_link(interface, index);
518 	return __cvmx_helper_sgmii_hardware_init_link_speed(interface, index,
519 							    link_info);
520 }
521 
522 /**
523  * Configure a port for internal and/or external loopback. Internal
524  * loopback causes packets sent by the port to be received by
525  * Octeon. External loopback causes packets received from the wire to
526  * sent out again.
527  *
528  * @ipd_port: IPD/PKO port to loopback.
529  * @enable_internal:
530  *		   Non zero if you want internal loopback
531  * @enable_external:
532  *		   Non zero if you want external loopback
533  *
534  * Returns Zero on success, negative on failure.
535  */
536 int __cvmx_helper_sgmii_configure_loopback(int ipd_port, int enable_internal,
537 					   int enable_external)
538 {
539 	int interface = cvmx_helper_get_interface_num(ipd_port);
540 	int index = cvmx_helper_get_interface_index_num(ipd_port);
541 	union cvmx_pcsx_mrx_control_reg pcsx_mrx_control_reg;
542 	union cvmx_pcsx_miscx_ctl_reg pcsx_miscx_ctl_reg;
543 
544 	pcsx_mrx_control_reg.u64 =
545 	    cvmx_read_csr(CVMX_PCSX_MRX_CONTROL_REG(index, interface));
546 	pcsx_mrx_control_reg.s.loopbck1 = enable_internal;
547 	cvmx_write_csr(CVMX_PCSX_MRX_CONTROL_REG(index, interface),
548 		       pcsx_mrx_control_reg.u64);
549 
550 	pcsx_miscx_ctl_reg.u64 =
551 	    cvmx_read_csr(CVMX_PCSX_MISCX_CTL_REG(index, interface));
552 	pcsx_miscx_ctl_reg.s.loopbck2 = enable_external;
553 	cvmx_write_csr(CVMX_PCSX_MISCX_CTL_REG(index, interface),
554 		       pcsx_miscx_ctl_reg.u64);
555 
556 	__cvmx_helper_sgmii_hardware_init_link(interface, index);
557 	return 0;
558 }
559