1 /*******************************************************************************
2 
3   Intel(R) Gigabit Ethernet Linux driver
4   Copyright(c) 2007-2009 Intel Corporation.
5 
6   This program is free software; you can redistribute it and/or modify it
7   under the terms and conditions of the GNU General Public License,
8   version 2, as published by the Free Software Foundation.
9 
10   This program is distributed in the hope it will be useful, but WITHOUT
11   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13   more details.
14 
15   You should have received a copy of the GNU General Public License along with
16   this program; if not, write to the Free Software Foundation, Inc.,
17   51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
18 
19   The full GNU General Public License is included in this distribution in
20   the file called "COPYING".
21 
22   Contact Information:
23   e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
24   Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
25 
26 *******************************************************************************/
27 
28 #include <linux/if_ether.h>
29 #include <linux/delay.h>
30 
31 #include "e1000_mac.h"
32 #include "e1000_nvm.h"
33 
34 /**
35  *  igb_raise_eec_clk - Raise EEPROM clock
36  *  @hw: pointer to the HW structure
37  *  @eecd: pointer to the EEPROM
38  *
39  *  Enable/Raise the EEPROM clock bit.
40  **/
igb_raise_eec_clk(struct e1000_hw * hw,u32 * eecd)41 static void igb_raise_eec_clk(struct e1000_hw *hw, u32 *eecd)
42 {
43 	*eecd = *eecd | E1000_EECD_SK;
44 	wr32(E1000_EECD, *eecd);
45 	wrfl();
46 	udelay(hw->nvm.delay_usec);
47 }
48 
49 /**
50  *  igb_lower_eec_clk - Lower EEPROM clock
51  *  @hw: pointer to the HW structure
52  *  @eecd: pointer to the EEPROM
53  *
54  *  Clear/Lower the EEPROM clock bit.
55  **/
igb_lower_eec_clk(struct e1000_hw * hw,u32 * eecd)56 static void igb_lower_eec_clk(struct e1000_hw *hw, u32 *eecd)
57 {
58 	*eecd = *eecd & ~E1000_EECD_SK;
59 	wr32(E1000_EECD, *eecd);
60 	wrfl();
61 	udelay(hw->nvm.delay_usec);
62 }
63 
64 /**
65  *  igb_shift_out_eec_bits - Shift data bits our to the EEPROM
66  *  @hw: pointer to the HW structure
67  *  @data: data to send to the EEPROM
68  *  @count: number of bits to shift out
69  *
70  *  We need to shift 'count' bits out to the EEPROM.  So, the value in the
71  *  "data" parameter will be shifted out to the EEPROM one bit at a time.
72  *  In order to do this, "data" must be broken down into bits.
73  **/
igb_shift_out_eec_bits(struct e1000_hw * hw,u16 data,u16 count)74 static void igb_shift_out_eec_bits(struct e1000_hw *hw, u16 data, u16 count)
75 {
76 	struct e1000_nvm_info *nvm = &hw->nvm;
77 	u32 eecd = rd32(E1000_EECD);
78 	u32 mask;
79 
80 	mask = 0x01 << (count - 1);
81 	if (nvm->type == e1000_nvm_eeprom_spi)
82 		eecd |= E1000_EECD_DO;
83 
84 	do {
85 		eecd &= ~E1000_EECD_DI;
86 
87 		if (data & mask)
88 			eecd |= E1000_EECD_DI;
89 
90 		wr32(E1000_EECD, eecd);
91 		wrfl();
92 
93 		udelay(nvm->delay_usec);
94 
95 		igb_raise_eec_clk(hw, &eecd);
96 		igb_lower_eec_clk(hw, &eecd);
97 
98 		mask >>= 1;
99 	} while (mask);
100 
101 	eecd &= ~E1000_EECD_DI;
102 	wr32(E1000_EECD, eecd);
103 }
104 
105 /**
106  *  igb_shift_in_eec_bits - Shift data bits in from the EEPROM
107  *  @hw: pointer to the HW structure
108  *  @count: number of bits to shift in
109  *
110  *  In order to read a register from the EEPROM, we need to shift 'count' bits
111  *  in from the EEPROM.  Bits are "shifted in" by raising the clock input to
112  *  the EEPROM (setting the SK bit), and then reading the value of the data out
113  *  "DO" bit.  During this "shifting in" process the data in "DI" bit should
114  *  always be clear.
115  **/
igb_shift_in_eec_bits(struct e1000_hw * hw,u16 count)116 static u16 igb_shift_in_eec_bits(struct e1000_hw *hw, u16 count)
117 {
118 	u32 eecd;
119 	u32 i;
120 	u16 data;
121 
122 	eecd = rd32(E1000_EECD);
123 
124 	eecd &= ~(E1000_EECD_DO | E1000_EECD_DI);
125 	data = 0;
126 
127 	for (i = 0; i < count; i++) {
128 		data <<= 1;
129 		igb_raise_eec_clk(hw, &eecd);
130 
131 		eecd = rd32(E1000_EECD);
132 
133 		eecd &= ~E1000_EECD_DI;
134 		if (eecd & E1000_EECD_DO)
135 			data |= 1;
136 
137 		igb_lower_eec_clk(hw, &eecd);
138 	}
139 
140 	return data;
141 }
142 
143 /**
144  *  igb_poll_eerd_eewr_done - Poll for EEPROM read/write completion
145  *  @hw: pointer to the HW structure
146  *  @ee_reg: EEPROM flag for polling
147  *
148  *  Polls the EEPROM status bit for either read or write completion based
149  *  upon the value of 'ee_reg'.
150  **/
igb_poll_eerd_eewr_done(struct e1000_hw * hw,int ee_reg)151 static s32 igb_poll_eerd_eewr_done(struct e1000_hw *hw, int ee_reg)
152 {
153 	u32 attempts = 100000;
154 	u32 i, reg = 0;
155 	s32 ret_val = -E1000_ERR_NVM;
156 
157 	for (i = 0; i < attempts; i++) {
158 		if (ee_reg == E1000_NVM_POLL_READ)
159 			reg = rd32(E1000_EERD);
160 		else
161 			reg = rd32(E1000_EEWR);
162 
163 		if (reg & E1000_NVM_RW_REG_DONE) {
164 			ret_val = 0;
165 			break;
166 		}
167 
168 		udelay(5);
169 	}
170 
171 	return ret_val;
172 }
173 
174 /**
175  *  igb_acquire_nvm - Generic request for access to EEPROM
176  *  @hw: pointer to the HW structure
177  *
178  *  Set the EEPROM access request bit and wait for EEPROM access grant bit.
179  *  Return successful if access grant bit set, else clear the request for
180  *  EEPROM access and return -E1000_ERR_NVM (-1).
181  **/
igb_acquire_nvm(struct e1000_hw * hw)182 s32 igb_acquire_nvm(struct e1000_hw *hw)
183 {
184 	u32 eecd = rd32(E1000_EECD);
185 	s32 timeout = E1000_NVM_GRANT_ATTEMPTS;
186 	s32 ret_val = 0;
187 
188 
189 	wr32(E1000_EECD, eecd | E1000_EECD_REQ);
190 	eecd = rd32(E1000_EECD);
191 
192 	while (timeout) {
193 		if (eecd & E1000_EECD_GNT)
194 			break;
195 		udelay(5);
196 		eecd = rd32(E1000_EECD);
197 		timeout--;
198 	}
199 
200 	if (!timeout) {
201 		eecd &= ~E1000_EECD_REQ;
202 		wr32(E1000_EECD, eecd);
203 		hw_dbg("Could not acquire NVM grant\n");
204 		ret_val = -E1000_ERR_NVM;
205 	}
206 
207 	return ret_val;
208 }
209 
210 /**
211  *  igb_standby_nvm - Return EEPROM to standby state
212  *  @hw: pointer to the HW structure
213  *
214  *  Return the EEPROM to a standby state.
215  **/
igb_standby_nvm(struct e1000_hw * hw)216 static void igb_standby_nvm(struct e1000_hw *hw)
217 {
218 	struct e1000_nvm_info *nvm = &hw->nvm;
219 	u32 eecd = rd32(E1000_EECD);
220 
221 	if (nvm->type == e1000_nvm_eeprom_spi) {
222 		/* Toggle CS to flush commands */
223 		eecd |= E1000_EECD_CS;
224 		wr32(E1000_EECD, eecd);
225 		wrfl();
226 		udelay(nvm->delay_usec);
227 		eecd &= ~E1000_EECD_CS;
228 		wr32(E1000_EECD, eecd);
229 		wrfl();
230 		udelay(nvm->delay_usec);
231 	}
232 }
233 
234 /**
235  *  e1000_stop_nvm - Terminate EEPROM command
236  *  @hw: pointer to the HW structure
237  *
238  *  Terminates the current command by inverting the EEPROM's chip select pin.
239  **/
e1000_stop_nvm(struct e1000_hw * hw)240 static void e1000_stop_nvm(struct e1000_hw *hw)
241 {
242 	u32 eecd;
243 
244 	eecd = rd32(E1000_EECD);
245 	if (hw->nvm.type == e1000_nvm_eeprom_spi) {
246 		/* Pull CS high */
247 		eecd |= E1000_EECD_CS;
248 		igb_lower_eec_clk(hw, &eecd);
249 	}
250 }
251 
252 /**
253  *  igb_release_nvm - Release exclusive access to EEPROM
254  *  @hw: pointer to the HW structure
255  *
256  *  Stop any current commands to the EEPROM and clear the EEPROM request bit.
257  **/
igb_release_nvm(struct e1000_hw * hw)258 void igb_release_nvm(struct e1000_hw *hw)
259 {
260 	u32 eecd;
261 
262 	e1000_stop_nvm(hw);
263 
264 	eecd = rd32(E1000_EECD);
265 	eecd &= ~E1000_EECD_REQ;
266 	wr32(E1000_EECD, eecd);
267 }
268 
269 /**
270  *  igb_ready_nvm_eeprom - Prepares EEPROM for read/write
271  *  @hw: pointer to the HW structure
272  *
273  *  Setups the EEPROM for reading and writing.
274  **/
igb_ready_nvm_eeprom(struct e1000_hw * hw)275 static s32 igb_ready_nvm_eeprom(struct e1000_hw *hw)
276 {
277 	struct e1000_nvm_info *nvm = &hw->nvm;
278 	u32 eecd = rd32(E1000_EECD);
279 	s32 ret_val = 0;
280 	u16 timeout = 0;
281 	u8 spi_stat_reg;
282 
283 
284 	if (nvm->type == e1000_nvm_eeprom_spi) {
285 		/* Clear SK and CS */
286 		eecd &= ~(E1000_EECD_CS | E1000_EECD_SK);
287 		wr32(E1000_EECD, eecd);
288 		udelay(1);
289 		timeout = NVM_MAX_RETRY_SPI;
290 
291 		/*
292 		 * Read "Status Register" repeatedly until the LSB is cleared.
293 		 * The EEPROM will signal that the command has been completed
294 		 * by clearing bit 0 of the internal status register.  If it's
295 		 * not cleared within 'timeout', then error out.
296 		 */
297 		while (timeout) {
298 			igb_shift_out_eec_bits(hw, NVM_RDSR_OPCODE_SPI,
299 						 hw->nvm.opcode_bits);
300 			spi_stat_reg = (u8)igb_shift_in_eec_bits(hw, 8);
301 			if (!(spi_stat_reg & NVM_STATUS_RDY_SPI))
302 				break;
303 
304 			udelay(5);
305 			igb_standby_nvm(hw);
306 			timeout--;
307 		}
308 
309 		if (!timeout) {
310 			hw_dbg("SPI NVM Status error\n");
311 			ret_val = -E1000_ERR_NVM;
312 			goto out;
313 		}
314 	}
315 
316 out:
317 	return ret_val;
318 }
319 
320 /**
321  *  igb_read_nvm_spi - Read EEPROM's using SPI
322  *  @hw: pointer to the HW structure
323  *  @offset: offset of word in the EEPROM to read
324  *  @words: number of words to read
325  *  @data: word read from the EEPROM
326  *
327  *  Reads a 16 bit word from the EEPROM.
328  **/
igb_read_nvm_spi(struct e1000_hw * hw,u16 offset,u16 words,u16 * data)329 s32 igb_read_nvm_spi(struct e1000_hw *hw, u16 offset, u16 words, u16 *data)
330 {
331 	struct e1000_nvm_info *nvm = &hw->nvm;
332 	u32 i = 0;
333 	s32 ret_val;
334 	u16 word_in;
335 	u8 read_opcode = NVM_READ_OPCODE_SPI;
336 
337 	/*
338 	 * A check for invalid values:  offset too large, too many words,
339 	 * and not enough words.
340 	 */
341 	if ((offset >= nvm->word_size) || (words > (nvm->word_size - offset)) ||
342 	    (words == 0)) {
343 		hw_dbg("nvm parameter(s) out of bounds\n");
344 		ret_val = -E1000_ERR_NVM;
345 		goto out;
346 	}
347 
348 	ret_val = nvm->ops.acquire(hw);
349 	if (ret_val)
350 		goto out;
351 
352 	ret_val = igb_ready_nvm_eeprom(hw);
353 	if (ret_val)
354 		goto release;
355 
356 	igb_standby_nvm(hw);
357 
358 	if ((nvm->address_bits == 8) && (offset >= 128))
359 		read_opcode |= NVM_A8_OPCODE_SPI;
360 
361 	/* Send the READ command (opcode + addr) */
362 	igb_shift_out_eec_bits(hw, read_opcode, nvm->opcode_bits);
363 	igb_shift_out_eec_bits(hw, (u16)(offset*2), nvm->address_bits);
364 
365 	/*
366 	 * Read the data.  SPI NVMs increment the address with each byte
367 	 * read and will roll over if reading beyond the end.  This allows
368 	 * us to read the whole NVM from any offset
369 	 */
370 	for (i = 0; i < words; i++) {
371 		word_in = igb_shift_in_eec_bits(hw, 16);
372 		data[i] = (word_in >> 8) | (word_in << 8);
373 	}
374 
375 release:
376 	nvm->ops.release(hw);
377 
378 out:
379 	return ret_val;
380 }
381 
382 /**
383  *  igb_read_nvm_eerd - Reads EEPROM using EERD register
384  *  @hw: pointer to the HW structure
385  *  @offset: offset of word in the EEPROM to read
386  *  @words: number of words to read
387  *  @data: word read from the EEPROM
388  *
389  *  Reads a 16 bit word from the EEPROM using the EERD register.
390  **/
igb_read_nvm_eerd(struct e1000_hw * hw,u16 offset,u16 words,u16 * data)391 s32 igb_read_nvm_eerd(struct e1000_hw *hw, u16 offset, u16 words, u16 *data)
392 {
393 	struct e1000_nvm_info *nvm = &hw->nvm;
394 	u32 i, eerd = 0;
395 	s32 ret_val = 0;
396 
397 	/*
398 	 * A check for invalid values:  offset too large, too many words,
399 	 * and not enough words.
400 	 */
401 	if ((offset >= nvm->word_size) || (words > (nvm->word_size - offset)) ||
402 	    (words == 0)) {
403 		hw_dbg("nvm parameter(s) out of bounds\n");
404 		ret_val = -E1000_ERR_NVM;
405 		goto out;
406 	}
407 
408 	for (i = 0; i < words; i++) {
409 		eerd = ((offset+i) << E1000_NVM_RW_ADDR_SHIFT) +
410 		       E1000_NVM_RW_REG_START;
411 
412 		wr32(E1000_EERD, eerd);
413 		ret_val = igb_poll_eerd_eewr_done(hw, E1000_NVM_POLL_READ);
414 		if (ret_val)
415 			break;
416 
417 		data[i] = (rd32(E1000_EERD) >>
418 			E1000_NVM_RW_REG_DATA);
419 	}
420 
421 out:
422 	return ret_val;
423 }
424 
425 /**
426  *  igb_write_nvm_spi - Write to EEPROM using SPI
427  *  @hw: pointer to the HW structure
428  *  @offset: offset within the EEPROM to be written to
429  *  @words: number of words to write
430  *  @data: 16 bit word(s) to be written to the EEPROM
431  *
432  *  Writes data to EEPROM at offset using SPI interface.
433  *
434  *  If e1000_update_nvm_checksum is not called after this function , the
435  *  EEPROM will most likley contain an invalid checksum.
436  **/
igb_write_nvm_spi(struct e1000_hw * hw,u16 offset,u16 words,u16 * data)437 s32 igb_write_nvm_spi(struct e1000_hw *hw, u16 offset, u16 words, u16 *data)
438 {
439 	struct e1000_nvm_info *nvm = &hw->nvm;
440 	s32 ret_val;
441 	u16 widx = 0;
442 
443 	/*
444 	 * A check for invalid values:  offset too large, too many words,
445 	 * and not enough words.
446 	 */
447 	if ((offset >= nvm->word_size) || (words > (nvm->word_size - offset)) ||
448 	    (words == 0)) {
449 		hw_dbg("nvm parameter(s) out of bounds\n");
450 		ret_val = -E1000_ERR_NVM;
451 		goto out;
452 	}
453 
454 	ret_val = hw->nvm.ops.acquire(hw);
455 	if (ret_val)
456 		goto out;
457 
458 	msleep(10);
459 
460 	while (widx < words) {
461 		u8 write_opcode = NVM_WRITE_OPCODE_SPI;
462 
463 		ret_val = igb_ready_nvm_eeprom(hw);
464 		if (ret_val)
465 			goto release;
466 
467 		igb_standby_nvm(hw);
468 
469 		/* Send the WRITE ENABLE command (8 bit opcode) */
470 		igb_shift_out_eec_bits(hw, NVM_WREN_OPCODE_SPI,
471 					 nvm->opcode_bits);
472 
473 		igb_standby_nvm(hw);
474 
475 		/*
476 		 * Some SPI eeproms use the 8th address bit embedded in the
477 		 * opcode
478 		 */
479 		if ((nvm->address_bits == 8) && (offset >= 128))
480 			write_opcode |= NVM_A8_OPCODE_SPI;
481 
482 		/* Send the Write command (8-bit opcode + addr) */
483 		igb_shift_out_eec_bits(hw, write_opcode, nvm->opcode_bits);
484 		igb_shift_out_eec_bits(hw, (u16)((offset + widx) * 2),
485 					 nvm->address_bits);
486 
487 		/* Loop to allow for up to whole page write of eeprom */
488 		while (widx < words) {
489 			u16 word_out = data[widx];
490 			word_out = (word_out >> 8) | (word_out << 8);
491 			igb_shift_out_eec_bits(hw, word_out, 16);
492 			widx++;
493 
494 			if ((((offset + widx) * 2) % nvm->page_size) == 0) {
495 				igb_standby_nvm(hw);
496 				break;
497 			}
498 		}
499 	}
500 
501 	msleep(10);
502 release:
503 	hw->nvm.ops.release(hw);
504 
505 out:
506 	return ret_val;
507 }
508 
509 /**
510  *  igb_read_part_string - Read device part number
511  *  @hw: pointer to the HW structure
512  *  @part_num: pointer to device part number
513  *  @part_num_size: size of part number buffer
514  *
515  *  Reads the product board assembly (PBA) number from the EEPROM and stores
516  *  the value in part_num.
517  **/
igb_read_part_string(struct e1000_hw * hw,u8 * part_num,u32 part_num_size)518 s32 igb_read_part_string(struct e1000_hw *hw, u8 *part_num, u32 part_num_size)
519 {
520 	s32 ret_val;
521 	u16 nvm_data;
522 	u16 pointer;
523 	u16 offset;
524 	u16 length;
525 
526 	if (part_num == NULL) {
527 		hw_dbg("PBA string buffer was null\n");
528 		ret_val = E1000_ERR_INVALID_ARGUMENT;
529 		goto out;
530 	}
531 
532 	ret_val = hw->nvm.ops.read(hw, NVM_PBA_OFFSET_0, 1, &nvm_data);
533 	if (ret_val) {
534 		hw_dbg("NVM Read Error\n");
535 		goto out;
536 	}
537 
538 	ret_val = hw->nvm.ops.read(hw, NVM_PBA_OFFSET_1, 1, &pointer);
539 	if (ret_val) {
540 		hw_dbg("NVM Read Error\n");
541 		goto out;
542 	}
543 
544 	/*
545 	 * if nvm_data is not ptr guard the PBA must be in legacy format which
546 	 * means pointer is actually our second data word for the PBA number
547 	 * and we can decode it into an ascii string
548 	 */
549 	if (nvm_data != NVM_PBA_PTR_GUARD) {
550 		hw_dbg("NVM PBA number is not stored as string\n");
551 
552 		/* we will need 11 characters to store the PBA */
553 		if (part_num_size < 11) {
554 			hw_dbg("PBA string buffer too small\n");
555 			return E1000_ERR_NO_SPACE;
556 		}
557 
558 		/* extract hex string from data and pointer */
559 		part_num[0] = (nvm_data >> 12) & 0xF;
560 		part_num[1] = (nvm_data >> 8) & 0xF;
561 		part_num[2] = (nvm_data >> 4) & 0xF;
562 		part_num[3] = nvm_data & 0xF;
563 		part_num[4] = (pointer >> 12) & 0xF;
564 		part_num[5] = (pointer >> 8) & 0xF;
565 		part_num[6] = '-';
566 		part_num[7] = 0;
567 		part_num[8] = (pointer >> 4) & 0xF;
568 		part_num[9] = pointer & 0xF;
569 
570 		/* put a null character on the end of our string */
571 		part_num[10] = '\0';
572 
573 		/* switch all the data but the '-' to hex char */
574 		for (offset = 0; offset < 10; offset++) {
575 			if (part_num[offset] < 0xA)
576 				part_num[offset] += '0';
577 			else if (part_num[offset] < 0x10)
578 				part_num[offset] += 'A' - 0xA;
579 		}
580 
581 		goto out;
582 	}
583 
584 	ret_val = hw->nvm.ops.read(hw, pointer, 1, &length);
585 	if (ret_val) {
586 		hw_dbg("NVM Read Error\n");
587 		goto out;
588 	}
589 
590 	if (length == 0xFFFF || length == 0) {
591 		hw_dbg("NVM PBA number section invalid length\n");
592 		ret_val = E1000_ERR_NVM_PBA_SECTION;
593 		goto out;
594 	}
595 	/* check if part_num buffer is big enough */
596 	if (part_num_size < (((u32)length * 2) - 1)) {
597 		hw_dbg("PBA string buffer too small\n");
598 		ret_val = E1000_ERR_NO_SPACE;
599 		goto out;
600 	}
601 
602 	/* trim pba length from start of string */
603 	pointer++;
604 	length--;
605 
606 	for (offset = 0; offset < length; offset++) {
607 		ret_val = hw->nvm.ops.read(hw, pointer + offset, 1, &nvm_data);
608 		if (ret_val) {
609 			hw_dbg("NVM Read Error\n");
610 			goto out;
611 		}
612 		part_num[offset * 2] = (u8)(nvm_data >> 8);
613 		part_num[(offset * 2) + 1] = (u8)(nvm_data & 0xFF);
614 	}
615 	part_num[offset * 2] = '\0';
616 
617 out:
618 	return ret_val;
619 }
620 
621 /**
622  *  igb_read_mac_addr - Read device MAC address
623  *  @hw: pointer to the HW structure
624  *
625  *  Reads the device MAC address from the EEPROM and stores the value.
626  *  Since devices with two ports use the same EEPROM, we increment the
627  *  last bit in the MAC address for the second port.
628  **/
igb_read_mac_addr(struct e1000_hw * hw)629 s32 igb_read_mac_addr(struct e1000_hw *hw)
630 {
631 	u32 rar_high;
632 	u32 rar_low;
633 	u16 i;
634 
635 	rar_high = rd32(E1000_RAH(0));
636 	rar_low = rd32(E1000_RAL(0));
637 
638 	for (i = 0; i < E1000_RAL_MAC_ADDR_LEN; i++)
639 		hw->mac.perm_addr[i] = (u8)(rar_low >> (i*8));
640 
641 	for (i = 0; i < E1000_RAH_MAC_ADDR_LEN; i++)
642 		hw->mac.perm_addr[i+4] = (u8)(rar_high >> (i*8));
643 
644 	for (i = 0; i < ETH_ALEN; i++)
645 		hw->mac.addr[i] = hw->mac.perm_addr[i];
646 
647 	return 0;
648 }
649 
650 /**
651  *  igb_validate_nvm_checksum - Validate EEPROM checksum
652  *  @hw: pointer to the HW structure
653  *
654  *  Calculates the EEPROM checksum by reading/adding each word of the EEPROM
655  *  and then verifies that the sum of the EEPROM is equal to 0xBABA.
656  **/
igb_validate_nvm_checksum(struct e1000_hw * hw)657 s32 igb_validate_nvm_checksum(struct e1000_hw *hw)
658 {
659 	s32 ret_val = 0;
660 	u16 checksum = 0;
661 	u16 i, nvm_data;
662 
663 	for (i = 0; i < (NVM_CHECKSUM_REG + 1); i++) {
664 		ret_val = hw->nvm.ops.read(hw, i, 1, &nvm_data);
665 		if (ret_val) {
666 			hw_dbg("NVM Read Error\n");
667 			goto out;
668 		}
669 		checksum += nvm_data;
670 	}
671 
672 	if (checksum != (u16) NVM_SUM) {
673 		hw_dbg("NVM Checksum Invalid\n");
674 		ret_val = -E1000_ERR_NVM;
675 		goto out;
676 	}
677 
678 out:
679 	return ret_val;
680 }
681 
682 /**
683  *  igb_update_nvm_checksum - Update EEPROM checksum
684  *  @hw: pointer to the HW structure
685  *
686  *  Updates the EEPROM checksum by reading/adding each word of the EEPROM
687  *  up to the checksum.  Then calculates the EEPROM checksum and writes the
688  *  value to the EEPROM.
689  **/
igb_update_nvm_checksum(struct e1000_hw * hw)690 s32 igb_update_nvm_checksum(struct e1000_hw *hw)
691 {
692 	s32  ret_val;
693 	u16 checksum = 0;
694 	u16 i, nvm_data;
695 
696 	for (i = 0; i < NVM_CHECKSUM_REG; i++) {
697 		ret_val = hw->nvm.ops.read(hw, i, 1, &nvm_data);
698 		if (ret_val) {
699 			hw_dbg("NVM Read Error while updating checksum.\n");
700 			goto out;
701 		}
702 		checksum += nvm_data;
703 	}
704 	checksum = (u16) NVM_SUM - checksum;
705 	ret_val = hw->nvm.ops.write(hw, NVM_CHECKSUM_REG, 1, &checksum);
706 	if (ret_val)
707 		hw_dbg("NVM Write Error while updating checksum.\n");
708 
709 out:
710 	return ret_val;
711 }
712 
713