1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c)  2018 Intel Corporation */
3 
4 #include <linux/pci.h>
5 #include <linux/delay.h>
6 
7 #include "igc_mac.h"
8 #include "igc_hw.h"
9 
10 /* forward declaration */
11 static s32 igc_set_fc_watermarks(struct igc_hw *hw);
12 
13 /**
14  * igc_disable_pcie_master - Disables PCI-express master access
15  * @hw: pointer to the HW structure
16  *
17  * Returns 0 (0) if successful, else returns -10
18  * (-IGC_ERR_MASTER_REQUESTS_PENDING) if master disable bit has not caused
19  * the master requests to be disabled.
20  *
21  * Disables PCI-Express master access and verifies there are no pending
22  * requests.
23  */
24 s32 igc_disable_pcie_master(struct igc_hw *hw)
25 {
26 	s32 timeout = MASTER_DISABLE_TIMEOUT;
27 	s32 ret_val = 0;
28 	u32 ctrl;
29 
30 	ctrl = rd32(IGC_CTRL);
31 	ctrl |= IGC_CTRL_GIO_MASTER_DISABLE;
32 	wr32(IGC_CTRL, ctrl);
33 
34 	while (timeout) {
35 		if (!(rd32(IGC_STATUS) &
36 		    IGC_STATUS_GIO_MASTER_ENABLE))
37 			break;
38 		usleep_range(2000, 3000);
39 		timeout--;
40 	}
41 
42 	if (!timeout) {
43 		hw_dbg("Master requests are pending.\n");
44 		ret_val = -IGC_ERR_MASTER_REQUESTS_PENDING;
45 		goto out;
46 	}
47 
48 out:
49 	return ret_val;
50 }
51 
52 /**
53  * igc_init_rx_addrs - Initialize receive addresses
54  * @hw: pointer to the HW structure
55  * @rar_count: receive address registers
56  *
57  * Setup the receive address registers by setting the base receive address
58  * register to the devices MAC address and clearing all the other receive
59  * address registers to 0.
60  */
61 void igc_init_rx_addrs(struct igc_hw *hw, u16 rar_count)
62 {
63 	u8 mac_addr[ETH_ALEN] = {0};
64 	u32 i;
65 
66 	/* Setup the receive address */
67 	hw_dbg("Programming MAC Address into RAR[0]\n");
68 
69 	hw->mac.ops.rar_set(hw, hw->mac.addr, 0);
70 
71 	/* Zero out the other (rar_entry_count - 1) receive addresses */
72 	hw_dbg("Clearing RAR[1-%u]\n", rar_count - 1);
73 	for (i = 1; i < rar_count; i++)
74 		hw->mac.ops.rar_set(hw, mac_addr, i);
75 }
76 
77 /**
78  * igc_setup_link - Setup flow control and link settings
79  * @hw: pointer to the HW structure
80  *
81  * Determines which flow control settings to use, then configures flow
82  * control.  Calls the appropriate media-specific link configuration
83  * function.  Assuming the adapter has a valid link partner, a valid link
84  * should be established.  Assumes the hardware has previously been reset
85  * and the transmitter and receiver are not enabled.
86  */
87 s32 igc_setup_link(struct igc_hw *hw)
88 {
89 	s32 ret_val = 0;
90 
91 	/* In the case of the phy reset being blocked, we already have a link.
92 	 * We do not need to set it up again.
93 	 */
94 	if (igc_check_reset_block(hw))
95 		goto out;
96 
97 	/* If requested flow control is set to default, set flow control
98 	 * to the both 'rx' and 'tx' pause frames.
99 	 */
100 	if (hw->fc.requested_mode == igc_fc_default)
101 		hw->fc.requested_mode = igc_fc_full;
102 
103 	/* We want to save off the original Flow Control configuration just
104 	 * in case we get disconnected and then reconnected into a different
105 	 * hub or switch with different Flow Control capabilities.
106 	 */
107 	hw->fc.current_mode = hw->fc.requested_mode;
108 
109 	hw_dbg("After fix-ups FlowControl is now = %x\n", hw->fc.current_mode);
110 
111 	/* Call the necessary media_type subroutine to configure the link. */
112 	ret_val = hw->mac.ops.setup_physical_interface(hw);
113 	if (ret_val)
114 		goto out;
115 
116 	/* Initialize the flow control address, type, and PAUSE timer
117 	 * registers to their default values.  This is done even if flow
118 	 * control is disabled, because it does not hurt anything to
119 	 * initialize these registers.
120 	 */
121 	hw_dbg("Initializing the Flow Control address, type and timer regs\n");
122 	wr32(IGC_FCT, FLOW_CONTROL_TYPE);
123 	wr32(IGC_FCAH, FLOW_CONTROL_ADDRESS_HIGH);
124 	wr32(IGC_FCAL, FLOW_CONTROL_ADDRESS_LOW);
125 
126 	wr32(IGC_FCTTV, hw->fc.pause_time);
127 
128 	ret_val = igc_set_fc_watermarks(hw);
129 
130 out:
131 	return ret_val;
132 }
133 
134 /**
135  * igc_force_mac_fc - Force the MAC's flow control settings
136  * @hw: pointer to the HW structure
137  *
138  * Force the MAC's flow control settings.  Sets the TFCE and RFCE bits in the
139  * device control register to reflect the adapter settings.  TFCE and RFCE
140  * need to be explicitly set by software when a copper PHY is used because
141  * autonegotiation is managed by the PHY rather than the MAC.  Software must
142  * also configure these bits when link is forced on a fiber connection.
143  */
144 s32 igc_force_mac_fc(struct igc_hw *hw)
145 {
146 	s32 ret_val = 0;
147 	u32 ctrl;
148 
149 	ctrl = rd32(IGC_CTRL);
150 
151 	/* Because we didn't get link via the internal auto-negotiation
152 	 * mechanism (we either forced link or we got link via PHY
153 	 * auto-neg), we have to manually enable/disable transmit an
154 	 * receive flow control.
155 	 *
156 	 * The "Case" statement below enables/disable flow control
157 	 * according to the "hw->fc.current_mode" parameter.
158 	 *
159 	 * The possible values of the "fc" parameter are:
160 	 *      0:  Flow control is completely disabled
161 	 *      1:  Rx flow control is enabled (we can receive pause
162 	 *          frames but not send pause frames).
163 	 *      2:  Tx flow control is enabled (we can send pause frames
164 	 *          frames but we do not receive pause frames).
165 	 *      3:  Both Rx and TX flow control (symmetric) is enabled.
166 	 *  other:  No other values should be possible at this point.
167 	 */
168 	hw_dbg("hw->fc.current_mode = %u\n", hw->fc.current_mode);
169 
170 	switch (hw->fc.current_mode) {
171 	case igc_fc_none:
172 		ctrl &= (~(IGC_CTRL_TFCE | IGC_CTRL_RFCE));
173 		break;
174 	case igc_fc_rx_pause:
175 		ctrl &= (~IGC_CTRL_TFCE);
176 		ctrl |= IGC_CTRL_RFCE;
177 		break;
178 	case igc_fc_tx_pause:
179 		ctrl &= (~IGC_CTRL_RFCE);
180 		ctrl |= IGC_CTRL_TFCE;
181 		break;
182 	case igc_fc_full:
183 		ctrl |= (IGC_CTRL_TFCE | IGC_CTRL_RFCE);
184 		break;
185 	default:
186 		hw_dbg("Flow control param set incorrectly\n");
187 		ret_val = -IGC_ERR_CONFIG;
188 		goto out;
189 	}
190 
191 	wr32(IGC_CTRL, ctrl);
192 
193 out:
194 	return ret_val;
195 }
196 
197 /**
198  * igc_set_fc_watermarks - Set flow control high/low watermarks
199  * @hw: pointer to the HW structure
200  *
201  * Sets the flow control high/low threshold (watermark) registers.  If
202  * flow control XON frame transmission is enabled, then set XON frame
203  * transmission as well.
204  */
205 static s32 igc_set_fc_watermarks(struct igc_hw *hw)
206 {
207 	u32 fcrtl = 0, fcrth = 0;
208 
209 	/* Set the flow control receive threshold registers.  Normally,
210 	 * these registers will be set to a default threshold that may be
211 	 * adjusted later by the driver's runtime code.  However, if the
212 	 * ability to transmit pause frames is not enabled, then these
213 	 * registers will be set to 0.
214 	 */
215 	if (hw->fc.current_mode & igc_fc_tx_pause) {
216 		/* We need to set up the Receive Threshold high and low water
217 		 * marks as well as (optionally) enabling the transmission of
218 		 * XON frames.
219 		 */
220 		fcrtl = hw->fc.low_water;
221 		if (hw->fc.send_xon)
222 			fcrtl |= IGC_FCRTL_XONE;
223 
224 		fcrth = hw->fc.high_water;
225 	}
226 	wr32(IGC_FCRTL, fcrtl);
227 	wr32(IGC_FCRTH, fcrth);
228 
229 	return 0;
230 }
231 
232 /**
233  * igc_clear_hw_cntrs_base - Clear base hardware counters
234  * @hw: pointer to the HW structure
235  *
236  * Clears the base hardware counters by reading the counter registers.
237  */
238 void igc_clear_hw_cntrs_base(struct igc_hw *hw)
239 {
240 	rd32(IGC_CRCERRS);
241 	rd32(IGC_SYMERRS);
242 	rd32(IGC_MPC);
243 	rd32(IGC_SCC);
244 	rd32(IGC_ECOL);
245 	rd32(IGC_MCC);
246 	rd32(IGC_LATECOL);
247 	rd32(IGC_COLC);
248 	rd32(IGC_DC);
249 	rd32(IGC_SEC);
250 	rd32(IGC_RLEC);
251 	rd32(IGC_XONRXC);
252 	rd32(IGC_XONTXC);
253 	rd32(IGC_XOFFRXC);
254 	rd32(IGC_XOFFTXC);
255 	rd32(IGC_FCRUC);
256 	rd32(IGC_GPRC);
257 	rd32(IGC_BPRC);
258 	rd32(IGC_MPRC);
259 	rd32(IGC_GPTC);
260 	rd32(IGC_GORCL);
261 	rd32(IGC_GORCH);
262 	rd32(IGC_GOTCL);
263 	rd32(IGC_GOTCH);
264 	rd32(IGC_RNBC);
265 	rd32(IGC_RUC);
266 	rd32(IGC_RFC);
267 	rd32(IGC_ROC);
268 	rd32(IGC_RJC);
269 	rd32(IGC_TORL);
270 	rd32(IGC_TORH);
271 	rd32(IGC_TOTL);
272 	rd32(IGC_TOTH);
273 	rd32(IGC_TPR);
274 	rd32(IGC_TPT);
275 	rd32(IGC_MPTC);
276 	rd32(IGC_BPTC);
277 
278 	rd32(IGC_PRC64);
279 	rd32(IGC_PRC127);
280 	rd32(IGC_PRC255);
281 	rd32(IGC_PRC511);
282 	rd32(IGC_PRC1023);
283 	rd32(IGC_PRC1522);
284 	rd32(IGC_PTC64);
285 	rd32(IGC_PTC127);
286 	rd32(IGC_PTC255);
287 	rd32(IGC_PTC511);
288 	rd32(IGC_PTC1023);
289 	rd32(IGC_PTC1522);
290 
291 	rd32(IGC_ALGNERRC);
292 	rd32(IGC_RXERRC);
293 	rd32(IGC_TNCRS);
294 	rd32(IGC_CEXTERR);
295 	rd32(IGC_TSCTC);
296 	rd32(IGC_TSCTFC);
297 
298 	rd32(IGC_MGTPRC);
299 	rd32(IGC_MGTPDC);
300 	rd32(IGC_MGTPTC);
301 
302 	rd32(IGC_IAC);
303 	rd32(IGC_ICRXOC);
304 
305 	rd32(IGC_ICRXPTC);
306 	rd32(IGC_ICRXATC);
307 	rd32(IGC_ICTXPTC);
308 	rd32(IGC_ICTXATC);
309 	rd32(IGC_ICTXQEC);
310 	rd32(IGC_ICTXQMTC);
311 	rd32(IGC_ICRXDMTC);
312 
313 	rd32(IGC_CBTMPC);
314 	rd32(IGC_HTDPMC);
315 	rd32(IGC_CBRMPC);
316 	rd32(IGC_RPTHC);
317 	rd32(IGC_HGPTC);
318 	rd32(IGC_HTCBDPC);
319 	rd32(IGC_HGORCL);
320 	rd32(IGC_HGORCH);
321 	rd32(IGC_HGOTCL);
322 	rd32(IGC_HGOTCH);
323 	rd32(IGC_LENERRS);
324 }
325 
326 /**
327  * igc_rar_set - Set receive address register
328  * @hw: pointer to the HW structure
329  * @addr: pointer to the receive address
330  * @index: receive address array register
331  *
332  * Sets the receive address array register at index to the address passed
333  * in by addr.
334  */
335 void igc_rar_set(struct igc_hw *hw, u8 *addr, u32 index)
336 {
337 	u32 rar_low, rar_high;
338 
339 	/* HW expects these in little endian so we reverse the byte order
340 	 * from network order (big endian) to little endian
341 	 */
342 	rar_low = ((u32)addr[0] |
343 		   ((u32)addr[1] << 8) |
344 		   ((u32)addr[2] << 16) | ((u32)addr[3] << 24));
345 
346 	rar_high = ((u32)addr[4] | ((u32)addr[5] << 8));
347 
348 	/* If MAC address zero, no need to set the AV bit */
349 	if (rar_low || rar_high)
350 		rar_high |= IGC_RAH_AV;
351 
352 	/* Some bridges will combine consecutive 32-bit writes into
353 	 * a single burst write, which will malfunction on some parts.
354 	 * The flushes avoid this.
355 	 */
356 	wr32(IGC_RAL(index), rar_low);
357 	wrfl();
358 	wr32(IGC_RAH(index), rar_high);
359 	wrfl();
360 }
361 
362 /**
363  * igc_check_for_copper_link - Check for link (Copper)
364  * @hw: pointer to the HW structure
365  *
366  * Checks to see of the link status of the hardware has changed.  If a
367  * change in link status has been detected, then we read the PHY registers
368  * to get the current speed/duplex if link exists.
369  */
370 s32 igc_check_for_copper_link(struct igc_hw *hw)
371 {
372 	struct igc_mac_info *mac = &hw->mac;
373 	s32 ret_val;
374 	bool link;
375 
376 	/* We only want to go out to the PHY registers to see if Auto-Neg
377 	 * has completed and/or if our link status has changed.  The
378 	 * get_link_status flag is set upon receiving a Link Status
379 	 * Change or Rx Sequence Error interrupt.
380 	 */
381 	if (!mac->get_link_status) {
382 		ret_val = 0;
383 		goto out;
384 	}
385 
386 	/* First we want to see if the MII Status Register reports
387 	 * link.  If so, then we want to get the current speed/duplex
388 	 * of the PHY.
389 	 */
390 	ret_val = igc_phy_has_link(hw, 1, 0, &link);
391 	if (ret_val)
392 		goto out;
393 
394 	if (!link)
395 		goto out; /* No link detected */
396 
397 	mac->get_link_status = false;
398 
399 	/* Check if there was DownShift, must be checked
400 	 * immediately after link-up
401 	 */
402 	igc_check_downshift(hw);
403 
404 	/* If we are forcing speed/duplex, then we simply return since
405 	 * we have already determined whether we have link or not.
406 	 */
407 	if (!mac->autoneg) {
408 		ret_val = -IGC_ERR_CONFIG;
409 		goto out;
410 	}
411 
412 	/* Auto-Neg is enabled.  Auto Speed Detection takes care
413 	 * of MAC speed/duplex configuration.  So we only need to
414 	 * configure Collision Distance in the MAC.
415 	 */
416 	igc_config_collision_dist(hw);
417 
418 	/* Configure Flow Control now that Auto-Neg has completed.
419 	 * First, we need to restore the desired flow control
420 	 * settings because we may have had to re-autoneg with a
421 	 * different link partner.
422 	 */
423 	ret_val = igc_config_fc_after_link_up(hw);
424 	if (ret_val)
425 		hw_dbg("Error configuring flow control\n");
426 
427 out:
428 	return ret_val;
429 }
430 
431 /**
432  * igc_config_collision_dist - Configure collision distance
433  * @hw: pointer to the HW structure
434  *
435  * Configures the collision distance to the default value and is used
436  * during link setup. Currently no func pointer exists and all
437  * implementations are handled in the generic version of this function.
438  */
439 void igc_config_collision_dist(struct igc_hw *hw)
440 {
441 	u32 tctl;
442 
443 	tctl = rd32(IGC_TCTL);
444 
445 	tctl &= ~IGC_TCTL_COLD;
446 	tctl |= IGC_COLLISION_DISTANCE << IGC_COLD_SHIFT;
447 
448 	wr32(IGC_TCTL, tctl);
449 	wrfl();
450 }
451 
452 /**
453  * igc_config_fc_after_link_up - Configures flow control after link
454  * @hw: pointer to the HW structure
455  *
456  * Checks the status of auto-negotiation after link up to ensure that the
457  * speed and duplex were not forced.  If the link needed to be forced, then
458  * flow control needs to be forced also.  If auto-negotiation is enabled
459  * and did not fail, then we configure flow control based on our link
460  * partner.
461  */
462 s32 igc_config_fc_after_link_up(struct igc_hw *hw)
463 {
464 	u16 mii_status_reg, mii_nway_adv_reg, mii_nway_lp_ability_reg;
465 	struct igc_mac_info *mac = &hw->mac;
466 	u16 speed, duplex;
467 	s32 ret_val = 0;
468 
469 	/* Check for the case where we have fiber media and auto-neg failed
470 	 * so we had to force link.  In this case, we need to force the
471 	 * configuration of the MAC to match the "fc" parameter.
472 	 */
473 	if (mac->autoneg_failed) {
474 		if (hw->phy.media_type == igc_media_type_copper)
475 			ret_val = igc_force_mac_fc(hw);
476 	}
477 
478 	if (ret_val) {
479 		hw_dbg("Error forcing flow control settings\n");
480 		goto out;
481 	}
482 
483 	/* Check for the case where we have copper media and auto-neg is
484 	 * enabled.  In this case, we need to check and see if Auto-Neg
485 	 * has completed, and if so, how the PHY and link partner has
486 	 * flow control configured.
487 	 */
488 	if (hw->phy.media_type == igc_media_type_copper && mac->autoneg) {
489 		/* Read the MII Status Register and check to see if AutoNeg
490 		 * has completed.  We read this twice because this reg has
491 		 * some "sticky" (latched) bits.
492 		 */
493 		ret_val = hw->phy.ops.read_reg(hw, PHY_STATUS,
494 					       &mii_status_reg);
495 		if (ret_val)
496 			goto out;
497 		ret_val = hw->phy.ops.read_reg(hw, PHY_STATUS,
498 					       &mii_status_reg);
499 		if (ret_val)
500 			goto out;
501 
502 		if (!(mii_status_reg & MII_SR_AUTONEG_COMPLETE)) {
503 			hw_dbg("Copper PHY and Auto Neg has not completed.\n");
504 			goto out;
505 		}
506 
507 		/* The AutoNeg process has completed, so we now need to
508 		 * read both the Auto Negotiation Advertisement
509 		 * Register (Address 4) and the Auto_Negotiation Base
510 		 * Page Ability Register (Address 5) to determine how
511 		 * flow control was negotiated.
512 		 */
513 		ret_val = hw->phy.ops.read_reg(hw, PHY_AUTONEG_ADV,
514 					       &mii_nway_adv_reg);
515 		if (ret_val)
516 			goto out;
517 		ret_val = hw->phy.ops.read_reg(hw, PHY_LP_ABILITY,
518 					       &mii_nway_lp_ability_reg);
519 		if (ret_val)
520 			goto out;
521 		/* Two bits in the Auto Negotiation Advertisement Register
522 		 * (Address 4) and two bits in the Auto Negotiation Base
523 		 * Page Ability Register (Address 5) determine flow control
524 		 * for both the PHY and the link partner.  The following
525 		 * table, taken out of the IEEE 802.3ab/D6.0 dated March 25,
526 		 * 1999, describes these PAUSE resolution bits and how flow
527 		 * control is determined based upon these settings.
528 		 * NOTE:  DC = Don't Care
529 		 *
530 		 *   LOCAL DEVICE  |   LINK PARTNER
531 		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | NIC Resolution
532 		 *-------|---------|-------|---------|--------------------
533 		 *   0   |    0    |  DC   |   DC    | igc_fc_none
534 		 *   0   |    1    |   0   |   DC    | igc_fc_none
535 		 *   0   |    1    |   1   |    0    | igc_fc_none
536 		 *   0   |    1    |   1   |    1    | igc_fc_tx_pause
537 		 *   1   |    0    |   0   |   DC    | igc_fc_none
538 		 *   1   |   DC    |   1   |   DC    | igc_fc_full
539 		 *   1   |    1    |   0   |    0    | igc_fc_none
540 		 *   1   |    1    |   0   |    1    | igc_fc_rx_pause
541 		 *
542 		 * Are both PAUSE bits set to 1?  If so, this implies
543 		 * Symmetric Flow Control is enabled at both ends.  The
544 		 * ASM_DIR bits are irrelevant per the spec.
545 		 *
546 		 * For Symmetric Flow Control:
547 		 *
548 		 *   LOCAL DEVICE  |   LINK PARTNER
549 		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | Result
550 		 *-------|---------|-------|---------|--------------------
551 		 *   1   |   DC    |   1   |   DC    | IGC_fc_full
552 		 *
553 		 */
554 		if ((mii_nway_adv_reg & NWAY_AR_PAUSE) &&
555 		    (mii_nway_lp_ability_reg & NWAY_LPAR_PAUSE)) {
556 			/* Now we need to check if the user selected RX ONLY
557 			 * of pause frames.  In this case, we had to advertise
558 			 * FULL flow control because we could not advertise RX
559 			 * ONLY. Hence, we must now check to see if we need to
560 			 * turn OFF  the TRANSMISSION of PAUSE frames.
561 			 */
562 			if (hw->fc.requested_mode == igc_fc_full) {
563 				hw->fc.current_mode = igc_fc_full;
564 				hw_dbg("Flow Control = FULL.\n");
565 			} else {
566 				hw->fc.current_mode = igc_fc_rx_pause;
567 				hw_dbg("Flow Control = RX PAUSE frames only.\n");
568 			}
569 		}
570 
571 		/* For receiving PAUSE frames ONLY.
572 		 *
573 		 *   LOCAL DEVICE  |   LINK PARTNER
574 		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | Result
575 		 *-------|---------|-------|---------|--------------------
576 		 *   0   |    1    |   1   |    1    | igc_fc_tx_pause
577 		 */
578 		else if (!(mii_nway_adv_reg & NWAY_AR_PAUSE) &&
579 			 (mii_nway_adv_reg & NWAY_AR_ASM_DIR) &&
580 			 (mii_nway_lp_ability_reg & NWAY_LPAR_PAUSE) &&
581 			 (mii_nway_lp_ability_reg & NWAY_LPAR_ASM_DIR)) {
582 			hw->fc.current_mode = igc_fc_tx_pause;
583 			hw_dbg("Flow Control = TX PAUSE frames only.\n");
584 		}
585 		/* For transmitting PAUSE frames ONLY.
586 		 *
587 		 *   LOCAL DEVICE  |   LINK PARTNER
588 		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | Result
589 		 *-------|---------|-------|---------|--------------------
590 		 *   1   |    1    |   0   |    1    | igc_fc_rx_pause
591 		 */
592 		else if ((mii_nway_adv_reg & NWAY_AR_PAUSE) &&
593 			 (mii_nway_adv_reg & NWAY_AR_ASM_DIR) &&
594 			 !(mii_nway_lp_ability_reg & NWAY_LPAR_PAUSE) &&
595 			 (mii_nway_lp_ability_reg & NWAY_LPAR_ASM_DIR)) {
596 			hw->fc.current_mode = igc_fc_rx_pause;
597 			hw_dbg("Flow Control = RX PAUSE frames only.\n");
598 		}
599 		/* Per the IEEE spec, at this point flow control should be
600 		 * disabled.  However, we want to consider that we could
601 		 * be connected to a legacy switch that doesn't advertise
602 		 * desired flow control, but can be forced on the link
603 		 * partner.  So if we advertised no flow control, that is
604 		 * what we will resolve to.  If we advertised some kind of
605 		 * receive capability (Rx Pause Only or Full Flow Control)
606 		 * and the link partner advertised none, we will configure
607 		 * ourselves to enable Rx Flow Control only.  We can do
608 		 * this safely for two reasons:  If the link partner really
609 		 * didn't want flow control enabled, and we enable Rx, no
610 		 * harm done since we won't be receiving any PAUSE frames
611 		 * anyway.  If the intent on the link partner was to have
612 		 * flow control enabled, then by us enabling RX only, we
613 		 * can at least receive pause frames and process them.
614 		 * This is a good idea because in most cases, since we are
615 		 * predominantly a server NIC, more times than not we will
616 		 * be asked to delay transmission of packets than asking
617 		 * our link partner to pause transmission of frames.
618 		 */
619 		else if ((hw->fc.requested_mode == igc_fc_none) ||
620 			 (hw->fc.requested_mode == igc_fc_tx_pause) ||
621 			 (hw->fc.strict_ieee)) {
622 			hw->fc.current_mode = igc_fc_none;
623 			hw_dbg("Flow Control = NONE.\n");
624 		} else {
625 			hw->fc.current_mode = igc_fc_rx_pause;
626 			hw_dbg("Flow Control = RX PAUSE frames only.\n");
627 		}
628 
629 		/* Now we need to do one last check...  If we auto-
630 		 * negotiated to HALF DUPLEX, flow control should not be
631 		 * enabled per IEEE 802.3 spec.
632 		 */
633 		ret_val = hw->mac.ops.get_speed_and_duplex(hw, &speed, &duplex);
634 		if (ret_val) {
635 			hw_dbg("Error getting link speed and duplex\n");
636 			goto out;
637 		}
638 
639 		if (duplex == HALF_DUPLEX)
640 			hw->fc.current_mode = igc_fc_none;
641 
642 		/* Now we call a subroutine to actually force the MAC
643 		 * controller to use the correct flow control settings.
644 		 */
645 		ret_val = igc_force_mac_fc(hw);
646 		if (ret_val) {
647 			hw_dbg("Error forcing flow control settings\n");
648 			goto out;
649 		}
650 	}
651 
652 out:
653 	return 0;
654 }
655 
656 /**
657  * igc_get_auto_rd_done - Check for auto read completion
658  * @hw: pointer to the HW structure
659  *
660  * Check EEPROM for Auto Read done bit.
661  */
662 s32 igc_get_auto_rd_done(struct igc_hw *hw)
663 {
664 	s32 ret_val = 0;
665 	s32 i = 0;
666 
667 	while (i < AUTO_READ_DONE_TIMEOUT) {
668 		if (rd32(IGC_EECD) & IGC_EECD_AUTO_RD)
669 			break;
670 		usleep_range(1000, 2000);
671 		i++;
672 	}
673 
674 	if (i == AUTO_READ_DONE_TIMEOUT) {
675 		hw_dbg("Auto read by HW from NVM has not completed.\n");
676 		ret_val = -IGC_ERR_RESET;
677 		goto out;
678 	}
679 
680 out:
681 	return ret_val;
682 }
683 
684 /**
685  * igc_get_speed_and_duplex_copper - Retrieve current speed/duplex
686  * @hw: pointer to the HW structure
687  * @speed: stores the current speed
688  * @duplex: stores the current duplex
689  *
690  * Read the status register for the current speed/duplex and store the current
691  * speed and duplex for copper connections.
692  */
693 s32 igc_get_speed_and_duplex_copper(struct igc_hw *hw, u16 *speed,
694 				    u16 *duplex)
695 {
696 	u32 status;
697 
698 	status = rd32(IGC_STATUS);
699 	if (status & IGC_STATUS_SPEED_1000) {
700 		/* For I225, STATUS will indicate 1G speed in both 1 Gbps
701 		 * and 2.5 Gbps link modes. An additional bit is used
702 		 * to differentiate between 1 Gbps and 2.5 Gbps.
703 		 */
704 		if (hw->mac.type == igc_i225 &&
705 		    (status & IGC_STATUS_SPEED_2500)) {
706 			*speed = SPEED_2500;
707 			hw_dbg("2500 Mbs, ");
708 		} else {
709 			*speed = SPEED_1000;
710 			hw_dbg("1000 Mbs, ");
711 		}
712 	} else if (status & IGC_STATUS_SPEED_100) {
713 		*speed = SPEED_100;
714 		hw_dbg("100 Mbs, ");
715 	} else {
716 		*speed = SPEED_10;
717 		hw_dbg("10 Mbs, ");
718 	}
719 
720 	if (status & IGC_STATUS_FD) {
721 		*duplex = FULL_DUPLEX;
722 		hw_dbg("Full Duplex\n");
723 	} else {
724 		*duplex = HALF_DUPLEX;
725 		hw_dbg("Half Duplex\n");
726 	}
727 
728 	return 0;
729 }
730 
731 /**
732  * igc_put_hw_semaphore - Release hardware semaphore
733  * @hw: pointer to the HW structure
734  *
735  * Release hardware semaphore used to access the PHY or NVM
736  */
737 void igc_put_hw_semaphore(struct igc_hw *hw)
738 {
739 	u32 swsm;
740 
741 	swsm = rd32(IGC_SWSM);
742 
743 	swsm &= ~(IGC_SWSM_SMBI | IGC_SWSM_SWESMBI);
744 
745 	wr32(IGC_SWSM, swsm);
746 }
747 
748 /**
749  * igc_enable_mng_pass_thru - Enable processing of ARP's
750  * @hw: pointer to the HW structure
751  *
752  * Verifies the hardware needs to leave interface enabled so that frames can
753  * be directed to and from the management interface.
754  */
755 bool igc_enable_mng_pass_thru(struct igc_hw *hw)
756 {
757 	bool ret_val = false;
758 	u32 fwsm, factps;
759 	u32 manc;
760 
761 	if (!hw->mac.asf_firmware_present)
762 		goto out;
763 
764 	manc = rd32(IGC_MANC);
765 
766 	if (!(manc & IGC_MANC_RCV_TCO_EN))
767 		goto out;
768 
769 	if (hw->mac.arc_subsystem_valid) {
770 		fwsm = rd32(IGC_FWSM);
771 		factps = rd32(IGC_FACTPS);
772 
773 		if (!(factps & IGC_FACTPS_MNGCG) &&
774 		    ((fwsm & IGC_FWSM_MODE_MASK) ==
775 		    (igc_mng_mode_pt << IGC_FWSM_MODE_SHIFT))) {
776 			ret_val = true;
777 			goto out;
778 		}
779 	} else {
780 		if ((manc & IGC_MANC_SMBUS_EN) &&
781 		    !(manc & IGC_MANC_ASF_EN)) {
782 			ret_val = true;
783 			goto out;
784 		}
785 	}
786 
787 out:
788 	return ret_val;
789 }
790