xref: /openbmc/linux/drivers/net/ethernet/intel/e1000e/mac.c (revision 6c870213d6f3a25981c10728f46294a3bed1703f)
1 /* Intel PRO/1000 Linux driver
2  * Copyright(c) 1999 - 2014 Intel Corporation.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms and conditions of the GNU General Public License,
6  * version 2, as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  *
13  * The full GNU General Public License is included in this distribution in
14  * the file called "COPYING".
15  *
16  * Contact Information:
17  * Linux NICS <linux.nics@intel.com>
18  * e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
19  * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
20  */
21 
22 #include "e1000.h"
23 
24 /**
25  *  e1000e_get_bus_info_pcie - Get PCIe bus information
26  *  @hw: pointer to the HW structure
27  *
28  *  Determines and stores the system bus information for a particular
29  *  network interface.  The following bus information is determined and stored:
30  *  bus speed, bus width, type (PCIe), and PCIe function.
31  **/
32 s32 e1000e_get_bus_info_pcie(struct e1000_hw *hw)
33 {
34 	struct e1000_mac_info *mac = &hw->mac;
35 	struct e1000_bus_info *bus = &hw->bus;
36 	struct e1000_adapter *adapter = hw->adapter;
37 	u16 pcie_link_status, cap_offset;
38 
39 	cap_offset = adapter->pdev->pcie_cap;
40 	if (!cap_offset) {
41 		bus->width = e1000_bus_width_unknown;
42 	} else {
43 		pci_read_config_word(adapter->pdev,
44 				     cap_offset + PCIE_LINK_STATUS,
45 				     &pcie_link_status);
46 		bus->width = (enum e1000_bus_width)((pcie_link_status &
47 						     PCIE_LINK_WIDTH_MASK) >>
48 						    PCIE_LINK_WIDTH_SHIFT);
49 	}
50 
51 	mac->ops.set_lan_id(hw);
52 
53 	return 0;
54 }
55 
56 /**
57  *  e1000_set_lan_id_multi_port_pcie - Set LAN id for PCIe multiple port devices
58  *
59  *  @hw: pointer to the HW structure
60  *
61  *  Determines the LAN function id by reading memory-mapped registers
62  *  and swaps the port value if requested.
63  **/
64 void e1000_set_lan_id_multi_port_pcie(struct e1000_hw *hw)
65 {
66 	struct e1000_bus_info *bus = &hw->bus;
67 	u32 reg;
68 
69 	/* The status register reports the correct function number
70 	 * for the device regardless of function swap state.
71 	 */
72 	reg = er32(STATUS);
73 	bus->func = (reg & E1000_STATUS_FUNC_MASK) >> E1000_STATUS_FUNC_SHIFT;
74 }
75 
76 /**
77  *  e1000_set_lan_id_single_port - Set LAN id for a single port device
78  *  @hw: pointer to the HW structure
79  *
80  *  Sets the LAN function id to zero for a single port device.
81  **/
82 void e1000_set_lan_id_single_port(struct e1000_hw *hw)
83 {
84 	struct e1000_bus_info *bus = &hw->bus;
85 
86 	bus->func = 0;
87 }
88 
89 /**
90  *  e1000_clear_vfta_generic - Clear VLAN filter table
91  *  @hw: pointer to the HW structure
92  *
93  *  Clears the register array which contains the VLAN filter table by
94  *  setting all the values to 0.
95  **/
96 void e1000_clear_vfta_generic(struct e1000_hw *hw)
97 {
98 	u32 offset;
99 
100 	for (offset = 0; offset < E1000_VLAN_FILTER_TBL_SIZE; offset++) {
101 		E1000_WRITE_REG_ARRAY(hw, E1000_VFTA, offset, 0);
102 		e1e_flush();
103 	}
104 }
105 
106 /**
107  *  e1000_write_vfta_generic - Write value to VLAN filter table
108  *  @hw: pointer to the HW structure
109  *  @offset: register offset in VLAN filter table
110  *  @value: register value written to VLAN filter table
111  *
112  *  Writes value at the given offset in the register array which stores
113  *  the VLAN filter table.
114  **/
115 void e1000_write_vfta_generic(struct e1000_hw *hw, u32 offset, u32 value)
116 {
117 	E1000_WRITE_REG_ARRAY(hw, E1000_VFTA, offset, value);
118 	e1e_flush();
119 }
120 
121 /**
122  *  e1000e_init_rx_addrs - Initialize receive address's
123  *  @hw: pointer to the HW structure
124  *  @rar_count: receive address registers
125  *
126  *  Setup the receive address registers by setting the base receive address
127  *  register to the devices MAC address and clearing all the other receive
128  *  address registers to 0.
129  **/
130 void e1000e_init_rx_addrs(struct e1000_hw *hw, u16 rar_count)
131 {
132 	u32 i;
133 	u8 mac_addr[ETH_ALEN] = { 0 };
134 
135 	/* Setup the receive address */
136 	e_dbg("Programming MAC Address into RAR[0]\n");
137 
138 	hw->mac.ops.rar_set(hw, hw->mac.addr, 0);
139 
140 	/* Zero out the other (rar_entry_count - 1) receive addresses */
141 	e_dbg("Clearing RAR[1-%u]\n", rar_count - 1);
142 	for (i = 1; i < rar_count; i++)
143 		hw->mac.ops.rar_set(hw, mac_addr, i);
144 }
145 
146 /**
147  *  e1000_check_alt_mac_addr_generic - Check for alternate MAC addr
148  *  @hw: pointer to the HW structure
149  *
150  *  Checks the nvm for an alternate MAC address.  An alternate MAC address
151  *  can be setup by pre-boot software and must be treated like a permanent
152  *  address and must override the actual permanent MAC address. If an
153  *  alternate MAC address is found it is programmed into RAR0, replacing
154  *  the permanent address that was installed into RAR0 by the Si on reset.
155  *  This function will return SUCCESS unless it encounters an error while
156  *  reading the EEPROM.
157  **/
158 s32 e1000_check_alt_mac_addr_generic(struct e1000_hw *hw)
159 {
160 	u32 i;
161 	s32 ret_val;
162 	u16 offset, nvm_alt_mac_addr_offset, nvm_data;
163 	u8 alt_mac_addr[ETH_ALEN];
164 
165 	ret_val = e1000_read_nvm(hw, NVM_COMPAT, 1, &nvm_data);
166 	if (ret_val)
167 		return ret_val;
168 
169 	/* not supported on 82573 */
170 	if (hw->mac.type == e1000_82573)
171 		return 0;
172 
173 	ret_val = e1000_read_nvm(hw, NVM_ALT_MAC_ADDR_PTR, 1,
174 				 &nvm_alt_mac_addr_offset);
175 	if (ret_val) {
176 		e_dbg("NVM Read Error\n");
177 		return ret_val;
178 	}
179 
180 	if ((nvm_alt_mac_addr_offset == 0xFFFF) ||
181 	    (nvm_alt_mac_addr_offset == 0x0000))
182 		/* There is no Alternate MAC Address */
183 		return 0;
184 
185 	if (hw->bus.func == E1000_FUNC_1)
186 		nvm_alt_mac_addr_offset += E1000_ALT_MAC_ADDRESS_OFFSET_LAN1;
187 	for (i = 0; i < ETH_ALEN; i += 2) {
188 		offset = nvm_alt_mac_addr_offset + (i >> 1);
189 		ret_val = e1000_read_nvm(hw, offset, 1, &nvm_data);
190 		if (ret_val) {
191 			e_dbg("NVM Read Error\n");
192 			return ret_val;
193 		}
194 
195 		alt_mac_addr[i] = (u8)(nvm_data & 0xFF);
196 		alt_mac_addr[i + 1] = (u8)(nvm_data >> 8);
197 	}
198 
199 	/* if multicast bit is set, the alternate address will not be used */
200 	if (is_multicast_ether_addr(alt_mac_addr)) {
201 		e_dbg("Ignoring Alternate Mac Address with MC bit set\n");
202 		return 0;
203 	}
204 
205 	/* We have a valid alternate MAC address, and we want to treat it the
206 	 * same as the normal permanent MAC address stored by the HW into the
207 	 * RAR. Do this by mapping this address into RAR0.
208 	 */
209 	hw->mac.ops.rar_set(hw, alt_mac_addr, 0);
210 
211 	return 0;
212 }
213 
214 /**
215  *  e1000e_rar_set_generic - Set receive address register
216  *  @hw: pointer to the HW structure
217  *  @addr: pointer to the receive address
218  *  @index: receive address array register
219  *
220  *  Sets the receive address array register at index to the address passed
221  *  in by addr.
222  **/
223 void e1000e_rar_set_generic(struct e1000_hw *hw, u8 *addr, u32 index)
224 {
225 	u32 rar_low, rar_high;
226 
227 	/* HW expects these in little endian so we reverse the byte order
228 	 * from network order (big endian) to little endian
229 	 */
230 	rar_low = ((u32)addr[0] | ((u32)addr[1] << 8) |
231 		   ((u32)addr[2] << 16) | ((u32)addr[3] << 24));
232 
233 	rar_high = ((u32)addr[4] | ((u32)addr[5] << 8));
234 
235 	/* If MAC address zero, no need to set the AV bit */
236 	if (rar_low || rar_high)
237 		rar_high |= E1000_RAH_AV;
238 
239 	/* Some bridges will combine consecutive 32-bit writes into
240 	 * a single burst write, which will malfunction on some parts.
241 	 * The flushes avoid this.
242 	 */
243 	ew32(RAL(index), rar_low);
244 	e1e_flush();
245 	ew32(RAH(index), rar_high);
246 	e1e_flush();
247 }
248 
249 /**
250  *  e1000_hash_mc_addr - Generate a multicast hash value
251  *  @hw: pointer to the HW structure
252  *  @mc_addr: pointer to a multicast address
253  *
254  *  Generates a multicast address hash value which is used to determine
255  *  the multicast filter table array address and new table value.
256  **/
257 static u32 e1000_hash_mc_addr(struct e1000_hw *hw, u8 *mc_addr)
258 {
259 	u32 hash_value, hash_mask;
260 	u8 bit_shift = 0;
261 
262 	/* Register count multiplied by bits per register */
263 	hash_mask = (hw->mac.mta_reg_count * 32) - 1;
264 
265 	/* For a mc_filter_type of 0, bit_shift is the number of left-shifts
266 	 * where 0xFF would still fall within the hash mask.
267 	 */
268 	while (hash_mask >> bit_shift != 0xFF)
269 		bit_shift++;
270 
271 	/* The portion of the address that is used for the hash table
272 	 * is determined by the mc_filter_type setting.
273 	 * The algorithm is such that there is a total of 8 bits of shifting.
274 	 * The bit_shift for a mc_filter_type of 0 represents the number of
275 	 * left-shifts where the MSB of mc_addr[5] would still fall within
276 	 * the hash_mask.  Case 0 does this exactly.  Since there are a total
277 	 * of 8 bits of shifting, then mc_addr[4] will shift right the
278 	 * remaining number of bits. Thus 8 - bit_shift.  The rest of the
279 	 * cases are a variation of this algorithm...essentially raising the
280 	 * number of bits to shift mc_addr[5] left, while still keeping the
281 	 * 8-bit shifting total.
282 	 *
283 	 * For example, given the following Destination MAC Address and an
284 	 * mta register count of 128 (thus a 4096-bit vector and 0xFFF mask),
285 	 * we can see that the bit_shift for case 0 is 4.  These are the hash
286 	 * values resulting from each mc_filter_type...
287 	 * [0] [1] [2] [3] [4] [5]
288 	 * 01  AA  00  12  34  56
289 	 * LSB           MSB
290 	 *
291 	 * case 0: hash_value = ((0x34 >> 4) | (0x56 << 4)) & 0xFFF = 0x563
292 	 * case 1: hash_value = ((0x34 >> 3) | (0x56 << 5)) & 0xFFF = 0xAC6
293 	 * case 2: hash_value = ((0x34 >> 2) | (0x56 << 6)) & 0xFFF = 0x163
294 	 * case 3: hash_value = ((0x34 >> 0) | (0x56 << 8)) & 0xFFF = 0x634
295 	 */
296 	switch (hw->mac.mc_filter_type) {
297 	default:
298 	case 0:
299 		break;
300 	case 1:
301 		bit_shift += 1;
302 		break;
303 	case 2:
304 		bit_shift += 2;
305 		break;
306 	case 3:
307 		bit_shift += 4;
308 		break;
309 	}
310 
311 	hash_value = hash_mask & (((mc_addr[4] >> (8 - bit_shift)) |
312 				   (((u16)mc_addr[5]) << bit_shift)));
313 
314 	return hash_value;
315 }
316 
317 /**
318  *  e1000e_update_mc_addr_list_generic - Update Multicast addresses
319  *  @hw: pointer to the HW structure
320  *  @mc_addr_list: array of multicast addresses to program
321  *  @mc_addr_count: number of multicast addresses to program
322  *
323  *  Updates entire Multicast Table Array.
324  *  The caller must have a packed mc_addr_list of multicast addresses.
325  **/
326 void e1000e_update_mc_addr_list_generic(struct e1000_hw *hw,
327 					u8 *mc_addr_list, u32 mc_addr_count)
328 {
329 	u32 hash_value, hash_bit, hash_reg;
330 	int i;
331 
332 	/* clear mta_shadow */
333 	memset(&hw->mac.mta_shadow, 0, sizeof(hw->mac.mta_shadow));
334 
335 	/* update mta_shadow from mc_addr_list */
336 	for (i = 0; (u32)i < mc_addr_count; i++) {
337 		hash_value = e1000_hash_mc_addr(hw, mc_addr_list);
338 
339 		hash_reg = (hash_value >> 5) & (hw->mac.mta_reg_count - 1);
340 		hash_bit = hash_value & 0x1F;
341 
342 		hw->mac.mta_shadow[hash_reg] |= (1 << hash_bit);
343 		mc_addr_list += (ETH_ALEN);
344 	}
345 
346 	/* replace the entire MTA table */
347 	for (i = hw->mac.mta_reg_count - 1; i >= 0; i--)
348 		E1000_WRITE_REG_ARRAY(hw, E1000_MTA, i, hw->mac.mta_shadow[i]);
349 	e1e_flush();
350 }
351 
352 /**
353  *  e1000e_clear_hw_cntrs_base - Clear base hardware counters
354  *  @hw: pointer to the HW structure
355  *
356  *  Clears the base hardware counters by reading the counter registers.
357  **/
358 void e1000e_clear_hw_cntrs_base(struct e1000_hw *hw)
359 {
360 	er32(CRCERRS);
361 	er32(SYMERRS);
362 	er32(MPC);
363 	er32(SCC);
364 	er32(ECOL);
365 	er32(MCC);
366 	er32(LATECOL);
367 	er32(COLC);
368 	er32(DC);
369 	er32(SEC);
370 	er32(RLEC);
371 	er32(XONRXC);
372 	er32(XONTXC);
373 	er32(XOFFRXC);
374 	er32(XOFFTXC);
375 	er32(FCRUC);
376 	er32(GPRC);
377 	er32(BPRC);
378 	er32(MPRC);
379 	er32(GPTC);
380 	er32(GORCL);
381 	er32(GORCH);
382 	er32(GOTCL);
383 	er32(GOTCH);
384 	er32(RNBC);
385 	er32(RUC);
386 	er32(RFC);
387 	er32(ROC);
388 	er32(RJC);
389 	er32(TORL);
390 	er32(TORH);
391 	er32(TOTL);
392 	er32(TOTH);
393 	er32(TPR);
394 	er32(TPT);
395 	er32(MPTC);
396 	er32(BPTC);
397 }
398 
399 /**
400  *  e1000e_check_for_copper_link - Check for link (Copper)
401  *  @hw: pointer to the HW structure
402  *
403  *  Checks to see of the link status of the hardware has changed.  If a
404  *  change in link status has been detected, then we read the PHY registers
405  *  to get the current speed/duplex if link exists.
406  **/
407 s32 e1000e_check_for_copper_link(struct e1000_hw *hw)
408 {
409 	struct e1000_mac_info *mac = &hw->mac;
410 	s32 ret_val;
411 	bool link;
412 
413 	/* We only want to go out to the PHY registers to see if Auto-Neg
414 	 * has completed and/or if our link status has changed.  The
415 	 * get_link_status flag is set upon receiving a Link Status
416 	 * Change or Rx Sequence Error interrupt.
417 	 */
418 	if (!mac->get_link_status)
419 		return 0;
420 
421 	/* First we want to see if the MII Status Register reports
422 	 * link.  If so, then we want to get the current speed/duplex
423 	 * of the PHY.
424 	 */
425 	ret_val = e1000e_phy_has_link_generic(hw, 1, 0, &link);
426 	if (ret_val)
427 		return ret_val;
428 
429 	if (!link)
430 		return 0;	/* No link detected */
431 
432 	mac->get_link_status = false;
433 
434 	/* Check if there was DownShift, must be checked
435 	 * immediately after link-up
436 	 */
437 	e1000e_check_downshift(hw);
438 
439 	/* If we are forcing speed/duplex, then we simply return since
440 	 * we have already determined whether we have link or not.
441 	 */
442 	if (!mac->autoneg)
443 		return -E1000_ERR_CONFIG;
444 
445 	/* Auto-Neg is enabled.  Auto Speed Detection takes care
446 	 * of MAC speed/duplex configuration.  So we only need to
447 	 * configure Collision Distance in the MAC.
448 	 */
449 	mac->ops.config_collision_dist(hw);
450 
451 	/* Configure Flow Control now that Auto-Neg has completed.
452 	 * First, we need to restore the desired flow control
453 	 * settings because we may have had to re-autoneg with a
454 	 * different link partner.
455 	 */
456 	ret_val = e1000e_config_fc_after_link_up(hw);
457 	if (ret_val)
458 		e_dbg("Error configuring flow control\n");
459 
460 	return ret_val;
461 }
462 
463 /**
464  *  e1000e_check_for_fiber_link - Check for link (Fiber)
465  *  @hw: pointer to the HW structure
466  *
467  *  Checks for link up on the hardware.  If link is not up and we have
468  *  a signal, then we need to force link up.
469  **/
470 s32 e1000e_check_for_fiber_link(struct e1000_hw *hw)
471 {
472 	struct e1000_mac_info *mac = &hw->mac;
473 	u32 rxcw;
474 	u32 ctrl;
475 	u32 status;
476 	s32 ret_val;
477 
478 	ctrl = er32(CTRL);
479 	status = er32(STATUS);
480 	rxcw = er32(RXCW);
481 
482 	/* If we don't have link (auto-negotiation failed or link partner
483 	 * cannot auto-negotiate), the cable is plugged in (we have signal),
484 	 * and our link partner is not trying to auto-negotiate with us (we
485 	 * are receiving idles or data), we need to force link up. We also
486 	 * need to give auto-negotiation time to complete, in case the cable
487 	 * was just plugged in. The autoneg_failed flag does this.
488 	 */
489 	/* (ctrl & E1000_CTRL_SWDPIN1) == 1 == have signal */
490 	if ((ctrl & E1000_CTRL_SWDPIN1) && !(status & E1000_STATUS_LU) &&
491 	    !(rxcw & E1000_RXCW_C)) {
492 		if (!mac->autoneg_failed) {
493 			mac->autoneg_failed = true;
494 			return 0;
495 		}
496 		e_dbg("NOT Rx'ing /C/, disable AutoNeg and force link.\n");
497 
498 		/* Disable auto-negotiation in the TXCW register */
499 		ew32(TXCW, (mac->txcw & ~E1000_TXCW_ANE));
500 
501 		/* Force link-up and also force full-duplex. */
502 		ctrl = er32(CTRL);
503 		ctrl |= (E1000_CTRL_SLU | E1000_CTRL_FD);
504 		ew32(CTRL, ctrl);
505 
506 		/* Configure Flow Control after forcing link up. */
507 		ret_val = e1000e_config_fc_after_link_up(hw);
508 		if (ret_val) {
509 			e_dbg("Error configuring flow control\n");
510 			return ret_val;
511 		}
512 	} else if ((ctrl & E1000_CTRL_SLU) && (rxcw & E1000_RXCW_C)) {
513 		/* If we are forcing link and we are receiving /C/ ordered
514 		 * sets, re-enable auto-negotiation in the TXCW register
515 		 * and disable forced link in the Device Control register
516 		 * in an attempt to auto-negotiate with our link partner.
517 		 */
518 		e_dbg("Rx'ing /C/, enable AutoNeg and stop forcing link.\n");
519 		ew32(TXCW, mac->txcw);
520 		ew32(CTRL, (ctrl & ~E1000_CTRL_SLU));
521 
522 		mac->serdes_has_link = true;
523 	}
524 
525 	return 0;
526 }
527 
528 /**
529  *  e1000e_check_for_serdes_link - Check for link (Serdes)
530  *  @hw: pointer to the HW structure
531  *
532  *  Checks for link up on the hardware.  If link is not up and we have
533  *  a signal, then we need to force link up.
534  **/
535 s32 e1000e_check_for_serdes_link(struct e1000_hw *hw)
536 {
537 	struct e1000_mac_info *mac = &hw->mac;
538 	u32 rxcw;
539 	u32 ctrl;
540 	u32 status;
541 	s32 ret_val;
542 
543 	ctrl = er32(CTRL);
544 	status = er32(STATUS);
545 	rxcw = er32(RXCW);
546 
547 	/* If we don't have link (auto-negotiation failed or link partner
548 	 * cannot auto-negotiate), and our link partner is not trying to
549 	 * auto-negotiate with us (we are receiving idles or data),
550 	 * we need to force link up. We also need to give auto-negotiation
551 	 * time to complete.
552 	 */
553 	/* (ctrl & E1000_CTRL_SWDPIN1) == 1 == have signal */
554 	if (!(status & E1000_STATUS_LU) && !(rxcw & E1000_RXCW_C)) {
555 		if (!mac->autoneg_failed) {
556 			mac->autoneg_failed = true;
557 			return 0;
558 		}
559 		e_dbg("NOT Rx'ing /C/, disable AutoNeg and force link.\n");
560 
561 		/* Disable auto-negotiation in the TXCW register */
562 		ew32(TXCW, (mac->txcw & ~E1000_TXCW_ANE));
563 
564 		/* Force link-up and also force full-duplex. */
565 		ctrl = er32(CTRL);
566 		ctrl |= (E1000_CTRL_SLU | E1000_CTRL_FD);
567 		ew32(CTRL, ctrl);
568 
569 		/* Configure Flow Control after forcing link up. */
570 		ret_val = e1000e_config_fc_after_link_up(hw);
571 		if (ret_val) {
572 			e_dbg("Error configuring flow control\n");
573 			return ret_val;
574 		}
575 	} else if ((ctrl & E1000_CTRL_SLU) && (rxcw & E1000_RXCW_C)) {
576 		/* If we are forcing link and we are receiving /C/ ordered
577 		 * sets, re-enable auto-negotiation in the TXCW register
578 		 * and disable forced link in the Device Control register
579 		 * in an attempt to auto-negotiate with our link partner.
580 		 */
581 		e_dbg("Rx'ing /C/, enable AutoNeg and stop forcing link.\n");
582 		ew32(TXCW, mac->txcw);
583 		ew32(CTRL, (ctrl & ~E1000_CTRL_SLU));
584 
585 		mac->serdes_has_link = true;
586 	} else if (!(E1000_TXCW_ANE & er32(TXCW))) {
587 		/* If we force link for non-auto-negotiation switch, check
588 		 * link status based on MAC synchronization for internal
589 		 * serdes media type.
590 		 */
591 		/* SYNCH bit and IV bit are sticky. */
592 		usleep_range(10, 20);
593 		rxcw = er32(RXCW);
594 		if (rxcw & E1000_RXCW_SYNCH) {
595 			if (!(rxcw & E1000_RXCW_IV)) {
596 				mac->serdes_has_link = true;
597 				e_dbg("SERDES: Link up - forced.\n");
598 			}
599 		} else {
600 			mac->serdes_has_link = false;
601 			e_dbg("SERDES: Link down - force failed.\n");
602 		}
603 	}
604 
605 	if (E1000_TXCW_ANE & er32(TXCW)) {
606 		status = er32(STATUS);
607 		if (status & E1000_STATUS_LU) {
608 			/* SYNCH bit and IV bit are sticky, so reread rxcw. */
609 			usleep_range(10, 20);
610 			rxcw = er32(RXCW);
611 			if (rxcw & E1000_RXCW_SYNCH) {
612 				if (!(rxcw & E1000_RXCW_IV)) {
613 					mac->serdes_has_link = true;
614 					e_dbg("SERDES: Link up - autoneg completed successfully.\n");
615 				} else {
616 					mac->serdes_has_link = false;
617 					e_dbg("SERDES: Link down - invalid codewords detected in autoneg.\n");
618 				}
619 			} else {
620 				mac->serdes_has_link = false;
621 				e_dbg("SERDES: Link down - no sync.\n");
622 			}
623 		} else {
624 			mac->serdes_has_link = false;
625 			e_dbg("SERDES: Link down - autoneg failed\n");
626 		}
627 	}
628 
629 	return 0;
630 }
631 
632 /**
633  *  e1000_set_default_fc_generic - Set flow control default values
634  *  @hw: pointer to the HW structure
635  *
636  *  Read the EEPROM for the default values for flow control and store the
637  *  values.
638  **/
639 static s32 e1000_set_default_fc_generic(struct e1000_hw *hw)
640 {
641 	s32 ret_val;
642 	u16 nvm_data;
643 
644 	/* Read and store word 0x0F of the EEPROM. This word contains bits
645 	 * that determine the hardware's default PAUSE (flow control) mode,
646 	 * a bit that determines whether the HW defaults to enabling or
647 	 * disabling auto-negotiation, and the direction of the
648 	 * SW defined pins. If there is no SW over-ride of the flow
649 	 * control setting, then the variable hw->fc will
650 	 * be initialized based on a value in the EEPROM.
651 	 */
652 	ret_val = e1000_read_nvm(hw, NVM_INIT_CONTROL2_REG, 1, &nvm_data);
653 
654 	if (ret_val) {
655 		e_dbg("NVM Read Error\n");
656 		return ret_val;
657 	}
658 
659 	if (!(nvm_data & NVM_WORD0F_PAUSE_MASK))
660 		hw->fc.requested_mode = e1000_fc_none;
661 	else if ((nvm_data & NVM_WORD0F_PAUSE_MASK) == NVM_WORD0F_ASM_DIR)
662 		hw->fc.requested_mode = e1000_fc_tx_pause;
663 	else
664 		hw->fc.requested_mode = e1000_fc_full;
665 
666 	return 0;
667 }
668 
669 /**
670  *  e1000e_setup_link_generic - Setup flow control and link settings
671  *  @hw: pointer to the HW structure
672  *
673  *  Determines which flow control settings to use, then configures flow
674  *  control.  Calls the appropriate media-specific link configuration
675  *  function.  Assuming the adapter has a valid link partner, a valid link
676  *  should be established.  Assumes the hardware has previously been reset
677  *  and the transmitter and receiver are not enabled.
678  **/
679 s32 e1000e_setup_link_generic(struct e1000_hw *hw)
680 {
681 	s32 ret_val;
682 
683 	/* In the case of the phy reset being blocked, we already have a link.
684 	 * We do not need to set it up again.
685 	 */
686 	if (hw->phy.ops.check_reset_block && hw->phy.ops.check_reset_block(hw))
687 		return 0;
688 
689 	/* If requested flow control is set to default, set flow control
690 	 * based on the EEPROM flow control settings.
691 	 */
692 	if (hw->fc.requested_mode == e1000_fc_default) {
693 		ret_val = e1000_set_default_fc_generic(hw);
694 		if (ret_val)
695 			return ret_val;
696 	}
697 
698 	/* Save off the requested flow control mode for use later.  Depending
699 	 * on the link partner's capabilities, we may or may not use this mode.
700 	 */
701 	hw->fc.current_mode = hw->fc.requested_mode;
702 
703 	e_dbg("After fix-ups FlowControl is now = %x\n", hw->fc.current_mode);
704 
705 	/* Call the necessary media_type subroutine to configure the link. */
706 	ret_val = hw->mac.ops.setup_physical_interface(hw);
707 	if (ret_val)
708 		return ret_val;
709 
710 	/* Initialize the flow control address, type, and PAUSE timer
711 	 * registers to their default values.  This is done even if flow
712 	 * control is disabled, because it does not hurt anything to
713 	 * initialize these registers.
714 	 */
715 	e_dbg("Initializing the Flow Control address, type and timer regs\n");
716 	ew32(FCT, FLOW_CONTROL_TYPE);
717 	ew32(FCAH, FLOW_CONTROL_ADDRESS_HIGH);
718 	ew32(FCAL, FLOW_CONTROL_ADDRESS_LOW);
719 
720 	ew32(FCTTV, hw->fc.pause_time);
721 
722 	return e1000e_set_fc_watermarks(hw);
723 }
724 
725 /**
726  *  e1000_commit_fc_settings_generic - Configure flow control
727  *  @hw: pointer to the HW structure
728  *
729  *  Write the flow control settings to the Transmit Config Word Register (TXCW)
730  *  base on the flow control settings in e1000_mac_info.
731  **/
732 static s32 e1000_commit_fc_settings_generic(struct e1000_hw *hw)
733 {
734 	struct e1000_mac_info *mac = &hw->mac;
735 	u32 txcw;
736 
737 	/* Check for a software override of the flow control settings, and
738 	 * setup the device accordingly.  If auto-negotiation is enabled, then
739 	 * software will have to set the "PAUSE" bits to the correct value in
740 	 * the Transmit Config Word Register (TXCW) and re-start auto-
741 	 * negotiation.  However, if auto-negotiation is disabled, then
742 	 * software will have to manually configure the two flow control enable
743 	 * bits in the CTRL register.
744 	 *
745 	 * The possible values of the "fc" parameter are:
746 	 *      0:  Flow control is completely disabled
747 	 *      1:  Rx flow control is enabled (we can receive pause frames,
748 	 *          but not send pause frames).
749 	 *      2:  Tx flow control is enabled (we can send pause frames but we
750 	 *          do not support receiving pause frames).
751 	 *      3:  Both Rx and Tx flow control (symmetric) are enabled.
752 	 */
753 	switch (hw->fc.current_mode) {
754 	case e1000_fc_none:
755 		/* Flow control completely disabled by a software over-ride. */
756 		txcw = (E1000_TXCW_ANE | E1000_TXCW_FD);
757 		break;
758 	case e1000_fc_rx_pause:
759 		/* Rx Flow control is enabled and Tx Flow control is disabled
760 		 * by a software over-ride. Since there really isn't a way to
761 		 * advertise that we are capable of Rx Pause ONLY, we will
762 		 * advertise that we support both symmetric and asymmetric Rx
763 		 * PAUSE.  Later, we will disable the adapter's ability to send
764 		 * PAUSE frames.
765 		 */
766 		txcw = (E1000_TXCW_ANE | E1000_TXCW_FD | E1000_TXCW_PAUSE_MASK);
767 		break;
768 	case e1000_fc_tx_pause:
769 		/* Tx Flow control is enabled, and Rx Flow control is disabled,
770 		 * by a software over-ride.
771 		 */
772 		txcw = (E1000_TXCW_ANE | E1000_TXCW_FD | E1000_TXCW_ASM_DIR);
773 		break;
774 	case e1000_fc_full:
775 		/* Flow control (both Rx and Tx) is enabled by a software
776 		 * over-ride.
777 		 */
778 		txcw = (E1000_TXCW_ANE | E1000_TXCW_FD | E1000_TXCW_PAUSE_MASK);
779 		break;
780 	default:
781 		e_dbg("Flow control param set incorrectly\n");
782 		return -E1000_ERR_CONFIG;
783 		break;
784 	}
785 
786 	ew32(TXCW, txcw);
787 	mac->txcw = txcw;
788 
789 	return 0;
790 }
791 
792 /**
793  *  e1000_poll_fiber_serdes_link_generic - Poll for link up
794  *  @hw: pointer to the HW structure
795  *
796  *  Polls for link up by reading the status register, if link fails to come
797  *  up with auto-negotiation, then the link is forced if a signal is detected.
798  **/
799 static s32 e1000_poll_fiber_serdes_link_generic(struct e1000_hw *hw)
800 {
801 	struct e1000_mac_info *mac = &hw->mac;
802 	u32 i, status;
803 	s32 ret_val;
804 
805 	/* If we have a signal (the cable is plugged in, or assumed true for
806 	 * serdes media) then poll for a "Link-Up" indication in the Device
807 	 * Status Register.  Time-out if a link isn't seen in 500 milliseconds
808 	 * seconds (Auto-negotiation should complete in less than 500
809 	 * milliseconds even if the other end is doing it in SW).
810 	 */
811 	for (i = 0; i < FIBER_LINK_UP_LIMIT; i++) {
812 		usleep_range(10000, 20000);
813 		status = er32(STATUS);
814 		if (status & E1000_STATUS_LU)
815 			break;
816 	}
817 	if (i == FIBER_LINK_UP_LIMIT) {
818 		e_dbg("Never got a valid link from auto-neg!!!\n");
819 		mac->autoneg_failed = true;
820 		/* AutoNeg failed to achieve a link, so we'll call
821 		 * mac->check_for_link. This routine will force the
822 		 * link up if we detect a signal. This will allow us to
823 		 * communicate with non-autonegotiating link partners.
824 		 */
825 		ret_val = mac->ops.check_for_link(hw);
826 		if (ret_val) {
827 			e_dbg("Error while checking for link\n");
828 			return ret_val;
829 		}
830 		mac->autoneg_failed = false;
831 	} else {
832 		mac->autoneg_failed = false;
833 		e_dbg("Valid Link Found\n");
834 	}
835 
836 	return 0;
837 }
838 
839 /**
840  *  e1000e_setup_fiber_serdes_link - Setup link for fiber/serdes
841  *  @hw: pointer to the HW structure
842  *
843  *  Configures collision distance and flow control for fiber and serdes
844  *  links.  Upon successful setup, poll for link.
845  **/
846 s32 e1000e_setup_fiber_serdes_link(struct e1000_hw *hw)
847 {
848 	u32 ctrl;
849 	s32 ret_val;
850 
851 	ctrl = er32(CTRL);
852 
853 	/* Take the link out of reset */
854 	ctrl &= ~E1000_CTRL_LRST;
855 
856 	hw->mac.ops.config_collision_dist(hw);
857 
858 	ret_val = e1000_commit_fc_settings_generic(hw);
859 	if (ret_val)
860 		return ret_val;
861 
862 	/* Since auto-negotiation is enabled, take the link out of reset (the
863 	 * link will be in reset, because we previously reset the chip). This
864 	 * will restart auto-negotiation.  If auto-negotiation is successful
865 	 * then the link-up status bit will be set and the flow control enable
866 	 * bits (RFCE and TFCE) will be set according to their negotiated value.
867 	 */
868 	e_dbg("Auto-negotiation enabled\n");
869 
870 	ew32(CTRL, ctrl);
871 	e1e_flush();
872 	usleep_range(1000, 2000);
873 
874 	/* For these adapters, the SW definable pin 1 is set when the optics
875 	 * detect a signal.  If we have a signal, then poll for a "Link-Up"
876 	 * indication.
877 	 */
878 	if (hw->phy.media_type == e1000_media_type_internal_serdes ||
879 	    (er32(CTRL) & E1000_CTRL_SWDPIN1)) {
880 		ret_val = e1000_poll_fiber_serdes_link_generic(hw);
881 	} else {
882 		e_dbg("No signal detected\n");
883 	}
884 
885 	return ret_val;
886 }
887 
888 /**
889  *  e1000e_config_collision_dist_generic - Configure collision distance
890  *  @hw: pointer to the HW structure
891  *
892  *  Configures the collision distance to the default value and is used
893  *  during link setup.
894  **/
895 void e1000e_config_collision_dist_generic(struct e1000_hw *hw)
896 {
897 	u32 tctl;
898 
899 	tctl = er32(TCTL);
900 
901 	tctl &= ~E1000_TCTL_COLD;
902 	tctl |= E1000_COLLISION_DISTANCE << E1000_COLD_SHIFT;
903 
904 	ew32(TCTL, tctl);
905 	e1e_flush();
906 }
907 
908 /**
909  *  e1000e_set_fc_watermarks - Set flow control high/low watermarks
910  *  @hw: pointer to the HW structure
911  *
912  *  Sets the flow control high/low threshold (watermark) registers.  If
913  *  flow control XON frame transmission is enabled, then set XON frame
914  *  transmission as well.
915  **/
916 s32 e1000e_set_fc_watermarks(struct e1000_hw *hw)
917 {
918 	u32 fcrtl = 0, fcrth = 0;
919 
920 	/* Set the flow control receive threshold registers.  Normally,
921 	 * these registers will be set to a default threshold that may be
922 	 * adjusted later by the driver's runtime code.  However, if the
923 	 * ability to transmit pause frames is not enabled, then these
924 	 * registers will be set to 0.
925 	 */
926 	if (hw->fc.current_mode & e1000_fc_tx_pause) {
927 		/* We need to set up the Receive Threshold high and low water
928 		 * marks as well as (optionally) enabling the transmission of
929 		 * XON frames.
930 		 */
931 		fcrtl = hw->fc.low_water;
932 		if (hw->fc.send_xon)
933 			fcrtl |= E1000_FCRTL_XONE;
934 
935 		fcrth = hw->fc.high_water;
936 	}
937 	ew32(FCRTL, fcrtl);
938 	ew32(FCRTH, fcrth);
939 
940 	return 0;
941 }
942 
943 /**
944  *  e1000e_force_mac_fc - Force the MAC's flow control settings
945  *  @hw: pointer to the HW structure
946  *
947  *  Force the MAC's flow control settings.  Sets the TFCE and RFCE bits in the
948  *  device control register to reflect the adapter settings.  TFCE and RFCE
949  *  need to be explicitly set by software when a copper PHY is used because
950  *  autonegotiation is managed by the PHY rather than the MAC.  Software must
951  *  also configure these bits when link is forced on a fiber connection.
952  **/
953 s32 e1000e_force_mac_fc(struct e1000_hw *hw)
954 {
955 	u32 ctrl;
956 
957 	ctrl = er32(CTRL);
958 
959 	/* Because we didn't get link via the internal auto-negotiation
960 	 * mechanism (we either forced link or we got link via PHY
961 	 * auto-neg), we have to manually enable/disable transmit an
962 	 * receive flow control.
963 	 *
964 	 * The "Case" statement below enables/disable flow control
965 	 * according to the "hw->fc.current_mode" parameter.
966 	 *
967 	 * The possible values of the "fc" parameter are:
968 	 *      0:  Flow control is completely disabled
969 	 *      1:  Rx flow control is enabled (we can receive pause
970 	 *          frames but not send pause frames).
971 	 *      2:  Tx flow control is enabled (we can send pause frames
972 	 *          frames but we do not receive pause frames).
973 	 *      3:  Both Rx and Tx flow control (symmetric) is enabled.
974 	 *  other:  No other values should be possible at this point.
975 	 */
976 	e_dbg("hw->fc.current_mode = %u\n", hw->fc.current_mode);
977 
978 	switch (hw->fc.current_mode) {
979 	case e1000_fc_none:
980 		ctrl &= (~(E1000_CTRL_TFCE | E1000_CTRL_RFCE));
981 		break;
982 	case e1000_fc_rx_pause:
983 		ctrl &= (~E1000_CTRL_TFCE);
984 		ctrl |= E1000_CTRL_RFCE;
985 		break;
986 	case e1000_fc_tx_pause:
987 		ctrl &= (~E1000_CTRL_RFCE);
988 		ctrl |= E1000_CTRL_TFCE;
989 		break;
990 	case e1000_fc_full:
991 		ctrl |= (E1000_CTRL_TFCE | E1000_CTRL_RFCE);
992 		break;
993 	default:
994 		e_dbg("Flow control param set incorrectly\n");
995 		return -E1000_ERR_CONFIG;
996 	}
997 
998 	ew32(CTRL, ctrl);
999 
1000 	return 0;
1001 }
1002 
1003 /**
1004  *  e1000e_config_fc_after_link_up - Configures flow control after link
1005  *  @hw: pointer to the HW structure
1006  *
1007  *  Checks the status of auto-negotiation after link up to ensure that the
1008  *  speed and duplex were not forced.  If the link needed to be forced, then
1009  *  flow control needs to be forced also.  If auto-negotiation is enabled
1010  *  and did not fail, then we configure flow control based on our link
1011  *  partner.
1012  **/
1013 s32 e1000e_config_fc_after_link_up(struct e1000_hw *hw)
1014 {
1015 	struct e1000_mac_info *mac = &hw->mac;
1016 	s32 ret_val = 0;
1017 	u32 pcs_status_reg, pcs_adv_reg, pcs_lp_ability_reg, pcs_ctrl_reg;
1018 	u16 mii_status_reg, mii_nway_adv_reg, mii_nway_lp_ability_reg;
1019 	u16 speed, duplex;
1020 
1021 	/* Check for the case where we have fiber media and auto-neg failed
1022 	 * so we had to force link.  In this case, we need to force the
1023 	 * configuration of the MAC to match the "fc" parameter.
1024 	 */
1025 	if (mac->autoneg_failed) {
1026 		if (hw->phy.media_type == e1000_media_type_fiber ||
1027 		    hw->phy.media_type == e1000_media_type_internal_serdes)
1028 			ret_val = e1000e_force_mac_fc(hw);
1029 	} else {
1030 		if (hw->phy.media_type == e1000_media_type_copper)
1031 			ret_val = e1000e_force_mac_fc(hw);
1032 	}
1033 
1034 	if (ret_val) {
1035 		e_dbg("Error forcing flow control settings\n");
1036 		return ret_val;
1037 	}
1038 
1039 	/* Check for the case where we have copper media and auto-neg is
1040 	 * enabled.  In this case, we need to check and see if Auto-Neg
1041 	 * has completed, and if so, how the PHY and link partner has
1042 	 * flow control configured.
1043 	 */
1044 	if ((hw->phy.media_type == e1000_media_type_copper) && mac->autoneg) {
1045 		/* Read the MII Status Register and check to see if AutoNeg
1046 		 * has completed.  We read this twice because this reg has
1047 		 * some "sticky" (latched) bits.
1048 		 */
1049 		ret_val = e1e_rphy(hw, MII_BMSR, &mii_status_reg);
1050 		if (ret_val)
1051 			return ret_val;
1052 		ret_val = e1e_rphy(hw, MII_BMSR, &mii_status_reg);
1053 		if (ret_val)
1054 			return ret_val;
1055 
1056 		if (!(mii_status_reg & BMSR_ANEGCOMPLETE)) {
1057 			e_dbg("Copper PHY and Auto Neg has not completed.\n");
1058 			return ret_val;
1059 		}
1060 
1061 		/* The AutoNeg process has completed, so we now need to
1062 		 * read both the Auto Negotiation Advertisement
1063 		 * Register (Address 4) and the Auto_Negotiation Base
1064 		 * Page Ability Register (Address 5) to determine how
1065 		 * flow control was negotiated.
1066 		 */
1067 		ret_val = e1e_rphy(hw, MII_ADVERTISE, &mii_nway_adv_reg);
1068 		if (ret_val)
1069 			return ret_val;
1070 		ret_val = e1e_rphy(hw, MII_LPA, &mii_nway_lp_ability_reg);
1071 		if (ret_val)
1072 			return ret_val;
1073 
1074 		/* Two bits in the Auto Negotiation Advertisement Register
1075 		 * (Address 4) and two bits in the Auto Negotiation Base
1076 		 * Page Ability Register (Address 5) determine flow control
1077 		 * for both the PHY and the link partner.  The following
1078 		 * table, taken out of the IEEE 802.3ab/D6.0 dated March 25,
1079 		 * 1999, describes these PAUSE resolution bits and how flow
1080 		 * control is determined based upon these settings.
1081 		 * NOTE:  DC = Don't Care
1082 		 *
1083 		 *   LOCAL DEVICE  |   LINK PARTNER
1084 		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | NIC Resolution
1085 		 *-------|---------|-------|---------|--------------------
1086 		 *   0   |    0    |  DC   |   DC    | e1000_fc_none
1087 		 *   0   |    1    |   0   |   DC    | e1000_fc_none
1088 		 *   0   |    1    |   1   |    0    | e1000_fc_none
1089 		 *   0   |    1    |   1   |    1    | e1000_fc_tx_pause
1090 		 *   1   |    0    |   0   |   DC    | e1000_fc_none
1091 		 *   1   |   DC    |   1   |   DC    | e1000_fc_full
1092 		 *   1   |    1    |   0   |    0    | e1000_fc_none
1093 		 *   1   |    1    |   0   |    1    | e1000_fc_rx_pause
1094 		 *
1095 		 * Are both PAUSE bits set to 1?  If so, this implies
1096 		 * Symmetric Flow Control is enabled at both ends.  The
1097 		 * ASM_DIR bits are irrelevant per the spec.
1098 		 *
1099 		 * For Symmetric Flow Control:
1100 		 *
1101 		 *   LOCAL DEVICE  |   LINK PARTNER
1102 		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | Result
1103 		 *-------|---------|-------|---------|--------------------
1104 		 *   1   |   DC    |   1   |   DC    | E1000_fc_full
1105 		 *
1106 		 */
1107 		if ((mii_nway_adv_reg & ADVERTISE_PAUSE_CAP) &&
1108 		    (mii_nway_lp_ability_reg & LPA_PAUSE_CAP)) {
1109 			/* Now we need to check if the user selected Rx ONLY
1110 			 * of pause frames.  In this case, we had to advertise
1111 			 * FULL flow control because we could not advertise Rx
1112 			 * ONLY. Hence, we must now check to see if we need to
1113 			 * turn OFF the TRANSMISSION of PAUSE frames.
1114 			 */
1115 			if (hw->fc.requested_mode == e1000_fc_full) {
1116 				hw->fc.current_mode = e1000_fc_full;
1117 				e_dbg("Flow Control = FULL.\n");
1118 			} else {
1119 				hw->fc.current_mode = e1000_fc_rx_pause;
1120 				e_dbg("Flow Control = Rx PAUSE frames only.\n");
1121 			}
1122 		}
1123 		/* For receiving PAUSE frames ONLY.
1124 		 *
1125 		 *   LOCAL DEVICE  |   LINK PARTNER
1126 		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | Result
1127 		 *-------|---------|-------|---------|--------------------
1128 		 *   0   |    1    |   1   |    1    | e1000_fc_tx_pause
1129 		 */
1130 		else if (!(mii_nway_adv_reg & ADVERTISE_PAUSE_CAP) &&
1131 			 (mii_nway_adv_reg & ADVERTISE_PAUSE_ASYM) &&
1132 			 (mii_nway_lp_ability_reg & LPA_PAUSE_CAP) &&
1133 			 (mii_nway_lp_ability_reg & LPA_PAUSE_ASYM)) {
1134 			hw->fc.current_mode = e1000_fc_tx_pause;
1135 			e_dbg("Flow Control = Tx PAUSE frames only.\n");
1136 		}
1137 		/* For transmitting PAUSE frames ONLY.
1138 		 *
1139 		 *   LOCAL DEVICE  |   LINK PARTNER
1140 		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | Result
1141 		 *-------|---------|-------|---------|--------------------
1142 		 *   1   |    1    |   0   |    1    | e1000_fc_rx_pause
1143 		 */
1144 		else if ((mii_nway_adv_reg & ADVERTISE_PAUSE_CAP) &&
1145 			 (mii_nway_adv_reg & ADVERTISE_PAUSE_ASYM) &&
1146 			 !(mii_nway_lp_ability_reg & LPA_PAUSE_CAP) &&
1147 			 (mii_nway_lp_ability_reg & LPA_PAUSE_ASYM)) {
1148 			hw->fc.current_mode = e1000_fc_rx_pause;
1149 			e_dbg("Flow Control = Rx PAUSE frames only.\n");
1150 		} else {
1151 			/* Per the IEEE spec, at this point flow control
1152 			 * should be disabled.
1153 			 */
1154 			hw->fc.current_mode = e1000_fc_none;
1155 			e_dbg("Flow Control = NONE.\n");
1156 		}
1157 
1158 		/* Now we need to do one last check...  If we auto-
1159 		 * negotiated to HALF DUPLEX, flow control should not be
1160 		 * enabled per IEEE 802.3 spec.
1161 		 */
1162 		ret_val = mac->ops.get_link_up_info(hw, &speed, &duplex);
1163 		if (ret_val) {
1164 			e_dbg("Error getting link speed and duplex\n");
1165 			return ret_val;
1166 		}
1167 
1168 		if (duplex == HALF_DUPLEX)
1169 			hw->fc.current_mode = e1000_fc_none;
1170 
1171 		/* Now we call a subroutine to actually force the MAC
1172 		 * controller to use the correct flow control settings.
1173 		 */
1174 		ret_val = e1000e_force_mac_fc(hw);
1175 		if (ret_val) {
1176 			e_dbg("Error forcing flow control settings\n");
1177 			return ret_val;
1178 		}
1179 	}
1180 
1181 	/* Check for the case where we have SerDes media and auto-neg is
1182 	 * enabled.  In this case, we need to check and see if Auto-Neg
1183 	 * has completed, and if so, how the PHY and link partner has
1184 	 * flow control configured.
1185 	 */
1186 	if ((hw->phy.media_type == e1000_media_type_internal_serdes) &&
1187 	    mac->autoneg) {
1188 		/* Read the PCS_LSTS and check to see if AutoNeg
1189 		 * has completed.
1190 		 */
1191 		pcs_status_reg = er32(PCS_LSTAT);
1192 
1193 		if (!(pcs_status_reg & E1000_PCS_LSTS_AN_COMPLETE)) {
1194 			e_dbg("PCS Auto Neg has not completed.\n");
1195 			return ret_val;
1196 		}
1197 
1198 		/* The AutoNeg process has completed, so we now need to
1199 		 * read both the Auto Negotiation Advertisement
1200 		 * Register (PCS_ANADV) and the Auto_Negotiation Base
1201 		 * Page Ability Register (PCS_LPAB) to determine how
1202 		 * flow control was negotiated.
1203 		 */
1204 		pcs_adv_reg = er32(PCS_ANADV);
1205 		pcs_lp_ability_reg = er32(PCS_LPAB);
1206 
1207 		/* Two bits in the Auto Negotiation Advertisement Register
1208 		 * (PCS_ANADV) and two bits in the Auto Negotiation Base
1209 		 * Page Ability Register (PCS_LPAB) determine flow control
1210 		 * for both the PHY and the link partner.  The following
1211 		 * table, taken out of the IEEE 802.3ab/D6.0 dated March 25,
1212 		 * 1999, describes these PAUSE resolution bits and how flow
1213 		 * control is determined based upon these settings.
1214 		 * NOTE:  DC = Don't Care
1215 		 *
1216 		 *   LOCAL DEVICE  |   LINK PARTNER
1217 		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | NIC Resolution
1218 		 *-------|---------|-------|---------|--------------------
1219 		 *   0   |    0    |  DC   |   DC    | e1000_fc_none
1220 		 *   0   |    1    |   0   |   DC    | e1000_fc_none
1221 		 *   0   |    1    |   1   |    0    | e1000_fc_none
1222 		 *   0   |    1    |   1   |    1    | e1000_fc_tx_pause
1223 		 *   1   |    0    |   0   |   DC    | e1000_fc_none
1224 		 *   1   |   DC    |   1   |   DC    | e1000_fc_full
1225 		 *   1   |    1    |   0   |    0    | e1000_fc_none
1226 		 *   1   |    1    |   0   |    1    | e1000_fc_rx_pause
1227 		 *
1228 		 * Are both PAUSE bits set to 1?  If so, this implies
1229 		 * Symmetric Flow Control is enabled at both ends.  The
1230 		 * ASM_DIR bits are irrelevant per the spec.
1231 		 *
1232 		 * For Symmetric Flow Control:
1233 		 *
1234 		 *   LOCAL DEVICE  |   LINK PARTNER
1235 		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | Result
1236 		 *-------|---------|-------|---------|--------------------
1237 		 *   1   |   DC    |   1   |   DC    | e1000_fc_full
1238 		 *
1239 		 */
1240 		if ((pcs_adv_reg & E1000_TXCW_PAUSE) &&
1241 		    (pcs_lp_ability_reg & E1000_TXCW_PAUSE)) {
1242 			/* Now we need to check if the user selected Rx ONLY
1243 			 * of pause frames.  In this case, we had to advertise
1244 			 * FULL flow control because we could not advertise Rx
1245 			 * ONLY. Hence, we must now check to see if we need to
1246 			 * turn OFF the TRANSMISSION of PAUSE frames.
1247 			 */
1248 			if (hw->fc.requested_mode == e1000_fc_full) {
1249 				hw->fc.current_mode = e1000_fc_full;
1250 				e_dbg("Flow Control = FULL.\n");
1251 			} else {
1252 				hw->fc.current_mode = e1000_fc_rx_pause;
1253 				e_dbg("Flow Control = Rx PAUSE frames only.\n");
1254 			}
1255 		}
1256 		/* For receiving PAUSE frames ONLY.
1257 		 *
1258 		 *   LOCAL DEVICE  |   LINK PARTNER
1259 		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | Result
1260 		 *-------|---------|-------|---------|--------------------
1261 		 *   0   |    1    |   1   |    1    | e1000_fc_tx_pause
1262 		 */
1263 		else if (!(pcs_adv_reg & E1000_TXCW_PAUSE) &&
1264 			 (pcs_adv_reg & E1000_TXCW_ASM_DIR) &&
1265 			 (pcs_lp_ability_reg & E1000_TXCW_PAUSE) &&
1266 			 (pcs_lp_ability_reg & E1000_TXCW_ASM_DIR)) {
1267 			hw->fc.current_mode = e1000_fc_tx_pause;
1268 			e_dbg("Flow Control = Tx PAUSE frames only.\n");
1269 		}
1270 		/* For transmitting PAUSE frames ONLY.
1271 		 *
1272 		 *   LOCAL DEVICE  |   LINK PARTNER
1273 		 * PAUSE | ASM_DIR | PAUSE | ASM_DIR | Result
1274 		 *-------|---------|-------|---------|--------------------
1275 		 *   1   |    1    |   0   |    1    | e1000_fc_rx_pause
1276 		 */
1277 		else if ((pcs_adv_reg & E1000_TXCW_PAUSE) &&
1278 			 (pcs_adv_reg & E1000_TXCW_ASM_DIR) &&
1279 			 !(pcs_lp_ability_reg & E1000_TXCW_PAUSE) &&
1280 			 (pcs_lp_ability_reg & E1000_TXCW_ASM_DIR)) {
1281 			hw->fc.current_mode = e1000_fc_rx_pause;
1282 			e_dbg("Flow Control = Rx PAUSE frames only.\n");
1283 		} else {
1284 			/* Per the IEEE spec, at this point flow control
1285 			 * should be disabled.
1286 			 */
1287 			hw->fc.current_mode = e1000_fc_none;
1288 			e_dbg("Flow Control = NONE.\n");
1289 		}
1290 
1291 		/* Now we call a subroutine to actually force the MAC
1292 		 * controller to use the correct flow control settings.
1293 		 */
1294 		pcs_ctrl_reg = er32(PCS_LCTL);
1295 		pcs_ctrl_reg |= E1000_PCS_LCTL_FORCE_FCTRL;
1296 		ew32(PCS_LCTL, pcs_ctrl_reg);
1297 
1298 		ret_val = e1000e_force_mac_fc(hw);
1299 		if (ret_val) {
1300 			e_dbg("Error forcing flow control settings\n");
1301 			return ret_val;
1302 		}
1303 	}
1304 
1305 	return 0;
1306 }
1307 
1308 /**
1309  *  e1000e_get_speed_and_duplex_copper - Retrieve current speed/duplex
1310  *  @hw: pointer to the HW structure
1311  *  @speed: stores the current speed
1312  *  @duplex: stores the current duplex
1313  *
1314  *  Read the status register for the current speed/duplex and store the current
1315  *  speed and duplex for copper connections.
1316  **/
1317 s32 e1000e_get_speed_and_duplex_copper(struct e1000_hw *hw, u16 *speed,
1318 				       u16 *duplex)
1319 {
1320 	u32 status;
1321 
1322 	status = er32(STATUS);
1323 	if (status & E1000_STATUS_SPEED_1000)
1324 		*speed = SPEED_1000;
1325 	else if (status & E1000_STATUS_SPEED_100)
1326 		*speed = SPEED_100;
1327 	else
1328 		*speed = SPEED_10;
1329 
1330 	if (status & E1000_STATUS_FD)
1331 		*duplex = FULL_DUPLEX;
1332 	else
1333 		*duplex = HALF_DUPLEX;
1334 
1335 	e_dbg("%u Mbps, %s Duplex\n",
1336 	      *speed == SPEED_1000 ? 1000 : *speed == SPEED_100 ? 100 : 10,
1337 	      *duplex == FULL_DUPLEX ? "Full" : "Half");
1338 
1339 	return 0;
1340 }
1341 
1342 /**
1343  *  e1000e_get_speed_and_duplex_fiber_serdes - Retrieve current speed/duplex
1344  *  @hw: pointer to the HW structure
1345  *  @speed: stores the current speed
1346  *  @duplex: stores the current duplex
1347  *
1348  *  Sets the speed and duplex to gigabit full duplex (the only possible option)
1349  *  for fiber/serdes links.
1350  **/
1351 s32 e1000e_get_speed_and_duplex_fiber_serdes(struct e1000_hw __always_unused
1352 					     *hw, u16 *speed, u16 *duplex)
1353 {
1354 	*speed = SPEED_1000;
1355 	*duplex = FULL_DUPLEX;
1356 
1357 	return 0;
1358 }
1359 
1360 /**
1361  *  e1000e_get_hw_semaphore - Acquire hardware semaphore
1362  *  @hw: pointer to the HW structure
1363  *
1364  *  Acquire the HW semaphore to access the PHY or NVM
1365  **/
1366 s32 e1000e_get_hw_semaphore(struct e1000_hw *hw)
1367 {
1368 	u32 swsm;
1369 	s32 timeout = hw->nvm.word_size + 1;
1370 	s32 i = 0;
1371 
1372 	/* Get the SW semaphore */
1373 	while (i < timeout) {
1374 		swsm = er32(SWSM);
1375 		if (!(swsm & E1000_SWSM_SMBI))
1376 			break;
1377 
1378 		usleep_range(50, 100);
1379 		i++;
1380 	}
1381 
1382 	if (i == timeout) {
1383 		e_dbg("Driver can't access device - SMBI bit is set.\n");
1384 		return -E1000_ERR_NVM;
1385 	}
1386 
1387 	/* Get the FW semaphore. */
1388 	for (i = 0; i < timeout; i++) {
1389 		swsm = er32(SWSM);
1390 		ew32(SWSM, swsm | E1000_SWSM_SWESMBI);
1391 
1392 		/* Semaphore acquired if bit latched */
1393 		if (er32(SWSM) & E1000_SWSM_SWESMBI)
1394 			break;
1395 
1396 		usleep_range(50, 100);
1397 	}
1398 
1399 	if (i == timeout) {
1400 		/* Release semaphores */
1401 		e1000e_put_hw_semaphore(hw);
1402 		e_dbg("Driver can't access the NVM\n");
1403 		return -E1000_ERR_NVM;
1404 	}
1405 
1406 	return 0;
1407 }
1408 
1409 /**
1410  *  e1000e_put_hw_semaphore - Release hardware semaphore
1411  *  @hw: pointer to the HW structure
1412  *
1413  *  Release hardware semaphore used to access the PHY or NVM
1414  **/
1415 void e1000e_put_hw_semaphore(struct e1000_hw *hw)
1416 {
1417 	u32 swsm;
1418 
1419 	swsm = er32(SWSM);
1420 	swsm &= ~(E1000_SWSM_SMBI | E1000_SWSM_SWESMBI);
1421 	ew32(SWSM, swsm);
1422 }
1423 
1424 /**
1425  *  e1000e_get_auto_rd_done - Check for auto read completion
1426  *  @hw: pointer to the HW structure
1427  *
1428  *  Check EEPROM for Auto Read done bit.
1429  **/
1430 s32 e1000e_get_auto_rd_done(struct e1000_hw *hw)
1431 {
1432 	s32 i = 0;
1433 
1434 	while (i < AUTO_READ_DONE_TIMEOUT) {
1435 		if (er32(EECD) & E1000_EECD_AUTO_RD)
1436 			break;
1437 		usleep_range(1000, 2000);
1438 		i++;
1439 	}
1440 
1441 	if (i == AUTO_READ_DONE_TIMEOUT) {
1442 		e_dbg("Auto read by HW from NVM has not completed.\n");
1443 		return -E1000_ERR_RESET;
1444 	}
1445 
1446 	return 0;
1447 }
1448 
1449 /**
1450  *  e1000e_valid_led_default - Verify a valid default LED config
1451  *  @hw: pointer to the HW structure
1452  *  @data: pointer to the NVM (EEPROM)
1453  *
1454  *  Read the EEPROM for the current default LED configuration.  If the
1455  *  LED configuration is not valid, set to a valid LED configuration.
1456  **/
1457 s32 e1000e_valid_led_default(struct e1000_hw *hw, u16 *data)
1458 {
1459 	s32 ret_val;
1460 
1461 	ret_val = e1000_read_nvm(hw, NVM_ID_LED_SETTINGS, 1, data);
1462 	if (ret_val) {
1463 		e_dbg("NVM Read Error\n");
1464 		return ret_val;
1465 	}
1466 
1467 	if (*data == ID_LED_RESERVED_0000 || *data == ID_LED_RESERVED_FFFF)
1468 		*data = ID_LED_DEFAULT;
1469 
1470 	return 0;
1471 }
1472 
1473 /**
1474  *  e1000e_id_led_init_generic -
1475  *  @hw: pointer to the HW structure
1476  *
1477  **/
1478 s32 e1000e_id_led_init_generic(struct e1000_hw *hw)
1479 {
1480 	struct e1000_mac_info *mac = &hw->mac;
1481 	s32 ret_val;
1482 	const u32 ledctl_mask = 0x000000FF;
1483 	const u32 ledctl_on = E1000_LEDCTL_MODE_LED_ON;
1484 	const u32 ledctl_off = E1000_LEDCTL_MODE_LED_OFF;
1485 	u16 data, i, temp;
1486 	const u16 led_mask = 0x0F;
1487 
1488 	ret_val = hw->nvm.ops.valid_led_default(hw, &data);
1489 	if (ret_val)
1490 		return ret_val;
1491 
1492 	mac->ledctl_default = er32(LEDCTL);
1493 	mac->ledctl_mode1 = mac->ledctl_default;
1494 	mac->ledctl_mode2 = mac->ledctl_default;
1495 
1496 	for (i = 0; i < 4; i++) {
1497 		temp = (data >> (i << 2)) & led_mask;
1498 		switch (temp) {
1499 		case ID_LED_ON1_DEF2:
1500 		case ID_LED_ON1_ON2:
1501 		case ID_LED_ON1_OFF2:
1502 			mac->ledctl_mode1 &= ~(ledctl_mask << (i << 3));
1503 			mac->ledctl_mode1 |= ledctl_on << (i << 3);
1504 			break;
1505 		case ID_LED_OFF1_DEF2:
1506 		case ID_LED_OFF1_ON2:
1507 		case ID_LED_OFF1_OFF2:
1508 			mac->ledctl_mode1 &= ~(ledctl_mask << (i << 3));
1509 			mac->ledctl_mode1 |= ledctl_off << (i << 3);
1510 			break;
1511 		default:
1512 			/* Do nothing */
1513 			break;
1514 		}
1515 		switch (temp) {
1516 		case ID_LED_DEF1_ON2:
1517 		case ID_LED_ON1_ON2:
1518 		case ID_LED_OFF1_ON2:
1519 			mac->ledctl_mode2 &= ~(ledctl_mask << (i << 3));
1520 			mac->ledctl_mode2 |= ledctl_on << (i << 3);
1521 			break;
1522 		case ID_LED_DEF1_OFF2:
1523 		case ID_LED_ON1_OFF2:
1524 		case ID_LED_OFF1_OFF2:
1525 			mac->ledctl_mode2 &= ~(ledctl_mask << (i << 3));
1526 			mac->ledctl_mode2 |= ledctl_off << (i << 3);
1527 			break;
1528 		default:
1529 			/* Do nothing */
1530 			break;
1531 		}
1532 	}
1533 
1534 	return 0;
1535 }
1536 
1537 /**
1538  *  e1000e_setup_led_generic - Configures SW controllable LED
1539  *  @hw: pointer to the HW structure
1540  *
1541  *  This prepares the SW controllable LED for use and saves the current state
1542  *  of the LED so it can be later restored.
1543  **/
1544 s32 e1000e_setup_led_generic(struct e1000_hw *hw)
1545 {
1546 	u32 ledctl;
1547 
1548 	if (hw->mac.ops.setup_led != e1000e_setup_led_generic)
1549 		return -E1000_ERR_CONFIG;
1550 
1551 	if (hw->phy.media_type == e1000_media_type_fiber) {
1552 		ledctl = er32(LEDCTL);
1553 		hw->mac.ledctl_default = ledctl;
1554 		/* Turn off LED0 */
1555 		ledctl &= ~(E1000_LEDCTL_LED0_IVRT | E1000_LEDCTL_LED0_BLINK |
1556 			    E1000_LEDCTL_LED0_MODE_MASK);
1557 		ledctl |= (E1000_LEDCTL_MODE_LED_OFF <<
1558 			   E1000_LEDCTL_LED0_MODE_SHIFT);
1559 		ew32(LEDCTL, ledctl);
1560 	} else if (hw->phy.media_type == e1000_media_type_copper) {
1561 		ew32(LEDCTL, hw->mac.ledctl_mode1);
1562 	}
1563 
1564 	return 0;
1565 }
1566 
1567 /**
1568  *  e1000e_cleanup_led_generic - Set LED config to default operation
1569  *  @hw: pointer to the HW structure
1570  *
1571  *  Remove the current LED configuration and set the LED configuration
1572  *  to the default value, saved from the EEPROM.
1573  **/
1574 s32 e1000e_cleanup_led_generic(struct e1000_hw *hw)
1575 {
1576 	ew32(LEDCTL, hw->mac.ledctl_default);
1577 	return 0;
1578 }
1579 
1580 /**
1581  *  e1000e_blink_led_generic - Blink LED
1582  *  @hw: pointer to the HW structure
1583  *
1584  *  Blink the LEDs which are set to be on.
1585  **/
1586 s32 e1000e_blink_led_generic(struct e1000_hw *hw)
1587 {
1588 	u32 ledctl_blink = 0;
1589 	u32 i;
1590 
1591 	if (hw->phy.media_type == e1000_media_type_fiber) {
1592 		/* always blink LED0 for PCI-E fiber */
1593 		ledctl_blink = E1000_LEDCTL_LED0_BLINK |
1594 		    (E1000_LEDCTL_MODE_LED_ON << E1000_LEDCTL_LED0_MODE_SHIFT);
1595 	} else {
1596 		/* Set the blink bit for each LED that's "on" (0x0E)
1597 		 * (or "off" if inverted) in ledctl_mode2.  The blink
1598 		 * logic in hardware only works when mode is set to "on"
1599 		 * so it must be changed accordingly when the mode is
1600 		 * "off" and inverted.
1601 		 */
1602 		ledctl_blink = hw->mac.ledctl_mode2;
1603 		for (i = 0; i < 32; i += 8) {
1604 			u32 mode = (hw->mac.ledctl_mode2 >> i) &
1605 			    E1000_LEDCTL_LED0_MODE_MASK;
1606 			u32 led_default = hw->mac.ledctl_default >> i;
1607 
1608 			if ((!(led_default & E1000_LEDCTL_LED0_IVRT) &&
1609 			     (mode == E1000_LEDCTL_MODE_LED_ON)) ||
1610 			    ((led_default & E1000_LEDCTL_LED0_IVRT) &&
1611 			     (mode == E1000_LEDCTL_MODE_LED_OFF))) {
1612 				ledctl_blink &=
1613 				    ~(E1000_LEDCTL_LED0_MODE_MASK << i);
1614 				ledctl_blink |= (E1000_LEDCTL_LED0_BLINK |
1615 						 E1000_LEDCTL_MODE_LED_ON) << i;
1616 			}
1617 		}
1618 	}
1619 
1620 	ew32(LEDCTL, ledctl_blink);
1621 
1622 	return 0;
1623 }
1624 
1625 /**
1626  *  e1000e_led_on_generic - Turn LED on
1627  *  @hw: pointer to the HW structure
1628  *
1629  *  Turn LED on.
1630  **/
1631 s32 e1000e_led_on_generic(struct e1000_hw *hw)
1632 {
1633 	u32 ctrl;
1634 
1635 	switch (hw->phy.media_type) {
1636 	case e1000_media_type_fiber:
1637 		ctrl = er32(CTRL);
1638 		ctrl &= ~E1000_CTRL_SWDPIN0;
1639 		ctrl |= E1000_CTRL_SWDPIO0;
1640 		ew32(CTRL, ctrl);
1641 		break;
1642 	case e1000_media_type_copper:
1643 		ew32(LEDCTL, hw->mac.ledctl_mode2);
1644 		break;
1645 	default:
1646 		break;
1647 	}
1648 
1649 	return 0;
1650 }
1651 
1652 /**
1653  *  e1000e_led_off_generic - Turn LED off
1654  *  @hw: pointer to the HW structure
1655  *
1656  *  Turn LED off.
1657  **/
1658 s32 e1000e_led_off_generic(struct e1000_hw *hw)
1659 {
1660 	u32 ctrl;
1661 
1662 	switch (hw->phy.media_type) {
1663 	case e1000_media_type_fiber:
1664 		ctrl = er32(CTRL);
1665 		ctrl |= E1000_CTRL_SWDPIN0;
1666 		ctrl |= E1000_CTRL_SWDPIO0;
1667 		ew32(CTRL, ctrl);
1668 		break;
1669 	case e1000_media_type_copper:
1670 		ew32(LEDCTL, hw->mac.ledctl_mode1);
1671 		break;
1672 	default:
1673 		break;
1674 	}
1675 
1676 	return 0;
1677 }
1678 
1679 /**
1680  *  e1000e_set_pcie_no_snoop - Set PCI-express capabilities
1681  *  @hw: pointer to the HW structure
1682  *  @no_snoop: bitmap of snoop events
1683  *
1684  *  Set the PCI-express register to snoop for events enabled in 'no_snoop'.
1685  **/
1686 void e1000e_set_pcie_no_snoop(struct e1000_hw *hw, u32 no_snoop)
1687 {
1688 	u32 gcr;
1689 
1690 	if (no_snoop) {
1691 		gcr = er32(GCR);
1692 		gcr &= ~(PCIE_NO_SNOOP_ALL);
1693 		gcr |= no_snoop;
1694 		ew32(GCR, gcr);
1695 	}
1696 }
1697 
1698 /**
1699  *  e1000e_disable_pcie_master - Disables PCI-express master access
1700  *  @hw: pointer to the HW structure
1701  *
1702  *  Returns 0 if successful, else returns -10
1703  *  (-E1000_ERR_MASTER_REQUESTS_PENDING) if master disable bit has not caused
1704  *  the master requests to be disabled.
1705  *
1706  *  Disables PCI-Express master access and verifies there are no pending
1707  *  requests.
1708  **/
1709 s32 e1000e_disable_pcie_master(struct e1000_hw *hw)
1710 {
1711 	u32 ctrl;
1712 	s32 timeout = MASTER_DISABLE_TIMEOUT;
1713 
1714 	ctrl = er32(CTRL);
1715 	ctrl |= E1000_CTRL_GIO_MASTER_DISABLE;
1716 	ew32(CTRL, ctrl);
1717 
1718 	while (timeout) {
1719 		if (!(er32(STATUS) & E1000_STATUS_GIO_MASTER_ENABLE))
1720 			break;
1721 		usleep_range(100, 200);
1722 		timeout--;
1723 	}
1724 
1725 	if (!timeout) {
1726 		e_dbg("Master requests are pending.\n");
1727 		return -E1000_ERR_MASTER_REQUESTS_PENDING;
1728 	}
1729 
1730 	return 0;
1731 }
1732 
1733 /**
1734  *  e1000e_reset_adaptive - Reset Adaptive Interframe Spacing
1735  *  @hw: pointer to the HW structure
1736  *
1737  *  Reset the Adaptive Interframe Spacing throttle to default values.
1738  **/
1739 void e1000e_reset_adaptive(struct e1000_hw *hw)
1740 {
1741 	struct e1000_mac_info *mac = &hw->mac;
1742 
1743 	if (!mac->adaptive_ifs) {
1744 		e_dbg("Not in Adaptive IFS mode!\n");
1745 		return;
1746 	}
1747 
1748 	mac->current_ifs_val = 0;
1749 	mac->ifs_min_val = IFS_MIN;
1750 	mac->ifs_max_val = IFS_MAX;
1751 	mac->ifs_step_size = IFS_STEP;
1752 	mac->ifs_ratio = IFS_RATIO;
1753 
1754 	mac->in_ifs_mode = false;
1755 	ew32(AIT, 0);
1756 }
1757 
1758 /**
1759  *  e1000e_update_adaptive - Update Adaptive Interframe Spacing
1760  *  @hw: pointer to the HW structure
1761  *
1762  *  Update the Adaptive Interframe Spacing Throttle value based on the
1763  *  time between transmitted packets and time between collisions.
1764  **/
1765 void e1000e_update_adaptive(struct e1000_hw *hw)
1766 {
1767 	struct e1000_mac_info *mac = &hw->mac;
1768 
1769 	if (!mac->adaptive_ifs) {
1770 		e_dbg("Not in Adaptive IFS mode!\n");
1771 		return;
1772 	}
1773 
1774 	if ((mac->collision_delta * mac->ifs_ratio) > mac->tx_packet_delta) {
1775 		if (mac->tx_packet_delta > MIN_NUM_XMITS) {
1776 			mac->in_ifs_mode = true;
1777 			if (mac->current_ifs_val < mac->ifs_max_val) {
1778 				if (!mac->current_ifs_val)
1779 					mac->current_ifs_val = mac->ifs_min_val;
1780 				else
1781 					mac->current_ifs_val +=
1782 					    mac->ifs_step_size;
1783 				ew32(AIT, mac->current_ifs_val);
1784 			}
1785 		}
1786 	} else {
1787 		if (mac->in_ifs_mode &&
1788 		    (mac->tx_packet_delta <= MIN_NUM_XMITS)) {
1789 			mac->current_ifs_val = 0;
1790 			mac->in_ifs_mode = false;
1791 			ew32(AIT, 0);
1792 		}
1793 	}
1794 }
1795