1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Copyright (C) 2000 Steven J. Hill (sjhill@realitydiluted.com)
4  *		  2002-2006 Thomas Gleixner (tglx@linutronix.de)
5  *
6  *  Credits:
7  *	David Woodhouse for adding multichip support
8  *
9  *	Aleph One Ltd. and Toby Churchill Ltd. for supporting the
10  *	rework for 2K page size chips
11  *
12  * This file contains all legacy helpers/code that should be removed
13  * at some point.
14  */
15 
16 #include <linux/delay.h>
17 #include <linux/io.h>
18 #include <linux/nmi.h>
19 
20 #include "internals.h"
21 
22 /**
23  * nand_read_byte - [DEFAULT] read one byte from the chip
24  * @chip: NAND chip object
25  *
26  * Default read function for 8bit buswidth
27  */
nand_read_byte(struct nand_chip * chip)28 static uint8_t nand_read_byte(struct nand_chip *chip)
29 {
30 	return readb(chip->legacy.IO_ADDR_R);
31 }
32 
33 /**
34  * nand_read_byte16 - [DEFAULT] read one byte endianness aware from the chip
35  * @chip: NAND chip object
36  *
37  * Default read function for 16bit buswidth with endianness conversion.
38  *
39  */
nand_read_byte16(struct nand_chip * chip)40 static uint8_t nand_read_byte16(struct nand_chip *chip)
41 {
42 	return (uint8_t) cpu_to_le16(readw(chip->legacy.IO_ADDR_R));
43 }
44 
45 /**
46  * nand_select_chip - [DEFAULT] control CE line
47  * @chip: NAND chip object
48  * @chipnr: chipnumber to select, -1 for deselect
49  *
50  * Default select function for 1 chip devices.
51  */
nand_select_chip(struct nand_chip * chip,int chipnr)52 static void nand_select_chip(struct nand_chip *chip, int chipnr)
53 {
54 	switch (chipnr) {
55 	case -1:
56 		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
57 				      0 | NAND_CTRL_CHANGE);
58 		break;
59 	case 0:
60 		break;
61 
62 	default:
63 		BUG();
64 	}
65 }
66 
67 /**
68  * nand_write_byte - [DEFAULT] write single byte to chip
69  * @chip: NAND chip object
70  * @byte: value to write
71  *
72  * Default function to write a byte to I/O[7:0]
73  */
nand_write_byte(struct nand_chip * chip,uint8_t byte)74 static void nand_write_byte(struct nand_chip *chip, uint8_t byte)
75 {
76 	chip->legacy.write_buf(chip, &byte, 1);
77 }
78 
79 /**
80  * nand_write_byte16 - [DEFAULT] write single byte to a chip with width 16
81  * @chip: NAND chip object
82  * @byte: value to write
83  *
84  * Default function to write a byte to I/O[7:0] on a 16-bit wide chip.
85  */
nand_write_byte16(struct nand_chip * chip,uint8_t byte)86 static void nand_write_byte16(struct nand_chip *chip, uint8_t byte)
87 {
88 	uint16_t word = byte;
89 
90 	/*
91 	 * It's not entirely clear what should happen to I/O[15:8] when writing
92 	 * a byte. The ONFi spec (Revision 3.1; 2012-09-19, Section 2.16) reads:
93 	 *
94 	 *    When the host supports a 16-bit bus width, only data is
95 	 *    transferred at the 16-bit width. All address and command line
96 	 *    transfers shall use only the lower 8-bits of the data bus. During
97 	 *    command transfers, the host may place any value on the upper
98 	 *    8-bits of the data bus. During address transfers, the host shall
99 	 *    set the upper 8-bits of the data bus to 00h.
100 	 *
101 	 * One user of the write_byte callback is nand_set_features. The
102 	 * four parameters are specified to be written to I/O[7:0], but this is
103 	 * neither an address nor a command transfer. Let's assume a 0 on the
104 	 * upper I/O lines is OK.
105 	 */
106 	chip->legacy.write_buf(chip, (uint8_t *)&word, 2);
107 }
108 
109 /**
110  * nand_write_buf - [DEFAULT] write buffer to chip
111  * @chip: NAND chip object
112  * @buf: data buffer
113  * @len: number of bytes to write
114  *
115  * Default write function for 8bit buswidth.
116  */
nand_write_buf(struct nand_chip * chip,const uint8_t * buf,int len)117 static void nand_write_buf(struct nand_chip *chip, const uint8_t *buf, int len)
118 {
119 	iowrite8_rep(chip->legacy.IO_ADDR_W, buf, len);
120 }
121 
122 /**
123  * nand_read_buf - [DEFAULT] read chip data into buffer
124  * @chip: NAND chip object
125  * @buf: buffer to store date
126  * @len: number of bytes to read
127  *
128  * Default read function for 8bit buswidth.
129  */
nand_read_buf(struct nand_chip * chip,uint8_t * buf,int len)130 static void nand_read_buf(struct nand_chip *chip, uint8_t *buf, int len)
131 {
132 	ioread8_rep(chip->legacy.IO_ADDR_R, buf, len);
133 }
134 
135 /**
136  * nand_write_buf16 - [DEFAULT] write buffer to chip
137  * @chip: NAND chip object
138  * @buf: data buffer
139  * @len: number of bytes to write
140  *
141  * Default write function for 16bit buswidth.
142  */
nand_write_buf16(struct nand_chip * chip,const uint8_t * buf,int len)143 static void nand_write_buf16(struct nand_chip *chip, const uint8_t *buf,
144 			     int len)
145 {
146 	u16 *p = (u16 *) buf;
147 
148 	iowrite16_rep(chip->legacy.IO_ADDR_W, p, len >> 1);
149 }
150 
151 /**
152  * nand_read_buf16 - [DEFAULT] read chip data into buffer
153  * @chip: NAND chip object
154  * @buf: buffer to store date
155  * @len: number of bytes to read
156  *
157  * Default read function for 16bit buswidth.
158  */
nand_read_buf16(struct nand_chip * chip,uint8_t * buf,int len)159 static void nand_read_buf16(struct nand_chip *chip, uint8_t *buf, int len)
160 {
161 	u16 *p = (u16 *) buf;
162 
163 	ioread16_rep(chip->legacy.IO_ADDR_R, p, len >> 1);
164 }
165 
166 /**
167  * panic_nand_wait_ready - [GENERIC] Wait for the ready pin after commands.
168  * @chip: NAND chip object
169  * @timeo: Timeout
170  *
171  * Helper function for nand_wait_ready used when needing to wait in interrupt
172  * context.
173  */
panic_nand_wait_ready(struct nand_chip * chip,unsigned long timeo)174 static void panic_nand_wait_ready(struct nand_chip *chip, unsigned long timeo)
175 {
176 	int i;
177 
178 	/* Wait for the device to get ready */
179 	for (i = 0; i < timeo; i++) {
180 		if (chip->legacy.dev_ready(chip))
181 			break;
182 		touch_softlockup_watchdog();
183 		mdelay(1);
184 	}
185 }
186 
187 /**
188  * nand_wait_ready - [GENERIC] Wait for the ready pin after commands.
189  * @chip: NAND chip object
190  *
191  * Wait for the ready pin after a command, and warn if a timeout occurs.
192  */
nand_wait_ready(struct nand_chip * chip)193 void nand_wait_ready(struct nand_chip *chip)
194 {
195 	struct mtd_info *mtd = nand_to_mtd(chip);
196 	unsigned long timeo = 400;
197 
198 	if (mtd->oops_panic_write)
199 		return panic_nand_wait_ready(chip, timeo);
200 
201 	/* Wait until command is processed or timeout occurs */
202 	timeo = jiffies + msecs_to_jiffies(timeo);
203 	do {
204 		if (chip->legacy.dev_ready(chip))
205 			return;
206 		cond_resched();
207 	} while (time_before(jiffies, timeo));
208 
209 	if (!chip->legacy.dev_ready(chip))
210 		pr_warn_ratelimited("timeout while waiting for chip to become ready\n");
211 }
212 EXPORT_SYMBOL_GPL(nand_wait_ready);
213 
214 /**
215  * nand_wait_status_ready - [GENERIC] Wait for the ready status after commands.
216  * @chip: NAND chip object
217  * @timeo: Timeout in ms
218  *
219  * Wait for status ready (i.e. command done) or timeout.
220  */
nand_wait_status_ready(struct nand_chip * chip,unsigned long timeo)221 static void nand_wait_status_ready(struct nand_chip *chip, unsigned long timeo)
222 {
223 	int ret;
224 
225 	timeo = jiffies + msecs_to_jiffies(timeo);
226 	do {
227 		u8 status;
228 
229 		ret = nand_read_data_op(chip, &status, sizeof(status), true,
230 					false);
231 		if (ret)
232 			return;
233 
234 		if (status & NAND_STATUS_READY)
235 			break;
236 		touch_softlockup_watchdog();
237 	} while (time_before(jiffies, timeo));
238 };
239 
240 /**
241  * nand_command - [DEFAULT] Send command to NAND device
242  * @chip: NAND chip object
243  * @command: the command to be sent
244  * @column: the column address for this command, -1 if none
245  * @page_addr: the page address for this command, -1 if none
246  *
247  * Send command to NAND device. This function is used for small page devices
248  * (512 Bytes per page).
249  */
nand_command(struct nand_chip * chip,unsigned int command,int column,int page_addr)250 static void nand_command(struct nand_chip *chip, unsigned int command,
251 			 int column, int page_addr)
252 {
253 	struct mtd_info *mtd = nand_to_mtd(chip);
254 	int ctrl = NAND_CTRL_CLE | NAND_CTRL_CHANGE;
255 
256 	/* Write out the command to the device */
257 	if (command == NAND_CMD_SEQIN) {
258 		int readcmd;
259 
260 		if (column >= mtd->writesize) {
261 			/* OOB area */
262 			column -= mtd->writesize;
263 			readcmd = NAND_CMD_READOOB;
264 		} else if (column < 256) {
265 			/* First 256 bytes --> READ0 */
266 			readcmd = NAND_CMD_READ0;
267 		} else {
268 			column -= 256;
269 			readcmd = NAND_CMD_READ1;
270 		}
271 		chip->legacy.cmd_ctrl(chip, readcmd, ctrl);
272 		ctrl &= ~NAND_CTRL_CHANGE;
273 	}
274 	if (command != NAND_CMD_NONE)
275 		chip->legacy.cmd_ctrl(chip, command, ctrl);
276 
277 	/* Address cycle, when necessary */
278 	ctrl = NAND_CTRL_ALE | NAND_CTRL_CHANGE;
279 	/* Serially input address */
280 	if (column != -1) {
281 		/* Adjust columns for 16 bit buswidth */
282 		if (chip->options & NAND_BUSWIDTH_16 &&
283 				!nand_opcode_8bits(command))
284 			column >>= 1;
285 		chip->legacy.cmd_ctrl(chip, column, ctrl);
286 		ctrl &= ~NAND_CTRL_CHANGE;
287 	}
288 	if (page_addr != -1) {
289 		chip->legacy.cmd_ctrl(chip, page_addr, ctrl);
290 		ctrl &= ~NAND_CTRL_CHANGE;
291 		chip->legacy.cmd_ctrl(chip, page_addr >> 8, ctrl);
292 		if (chip->options & NAND_ROW_ADDR_3)
293 			chip->legacy.cmd_ctrl(chip, page_addr >> 16, ctrl);
294 	}
295 	chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
296 			      NAND_NCE | NAND_CTRL_CHANGE);
297 
298 	/*
299 	 * Program and erase have their own busy handlers status and sequential
300 	 * in needs no delay
301 	 */
302 	switch (command) {
303 
304 	case NAND_CMD_NONE:
305 	case NAND_CMD_PAGEPROG:
306 	case NAND_CMD_ERASE1:
307 	case NAND_CMD_ERASE2:
308 	case NAND_CMD_SEQIN:
309 	case NAND_CMD_STATUS:
310 	case NAND_CMD_READID:
311 	case NAND_CMD_SET_FEATURES:
312 		return;
313 
314 	case NAND_CMD_RESET:
315 		if (chip->legacy.dev_ready)
316 			break;
317 		udelay(chip->legacy.chip_delay);
318 		chip->legacy.cmd_ctrl(chip, NAND_CMD_STATUS,
319 				      NAND_CTRL_CLE | NAND_CTRL_CHANGE);
320 		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
321 				      NAND_NCE | NAND_CTRL_CHANGE);
322 		/* EZ-NAND can take upto 250ms as per ONFi v4.0 */
323 		nand_wait_status_ready(chip, 250);
324 		return;
325 
326 		/* This applies to read commands */
327 	case NAND_CMD_READ0:
328 		/*
329 		 * READ0 is sometimes used to exit GET STATUS mode. When this
330 		 * is the case no address cycles are requested, and we can use
331 		 * this information to detect that we should not wait for the
332 		 * device to be ready.
333 		 */
334 		if (column == -1 && page_addr == -1)
335 			return;
336 		fallthrough;
337 	default:
338 		/*
339 		 * If we don't have access to the busy pin, we apply the given
340 		 * command delay
341 		 */
342 		if (!chip->legacy.dev_ready) {
343 			udelay(chip->legacy.chip_delay);
344 			return;
345 		}
346 	}
347 	/*
348 	 * Apply this short delay always to ensure that we do wait tWB in
349 	 * any case on any machine.
350 	 */
351 	ndelay(100);
352 
353 	nand_wait_ready(chip);
354 }
355 
nand_ccs_delay(struct nand_chip * chip)356 static void nand_ccs_delay(struct nand_chip *chip)
357 {
358 	const struct nand_sdr_timings *sdr =
359 		nand_get_sdr_timings(nand_get_interface_config(chip));
360 
361 	/*
362 	 * The controller already takes care of waiting for tCCS when the RNDIN
363 	 * or RNDOUT command is sent, return directly.
364 	 */
365 	if (!(chip->options & NAND_WAIT_TCCS))
366 		return;
367 
368 	/*
369 	 * Wait tCCS_min if it is correctly defined, otherwise wait 500ns
370 	 * (which should be safe for all NANDs).
371 	 */
372 	if (!IS_ERR(sdr) && nand_controller_can_setup_interface(chip))
373 		ndelay(sdr->tCCS_min / 1000);
374 	else
375 		ndelay(500);
376 }
377 
378 /**
379  * nand_command_lp - [DEFAULT] Send command to NAND large page device
380  * @chip: NAND chip object
381  * @command: the command to be sent
382  * @column: the column address for this command, -1 if none
383  * @page_addr: the page address for this command, -1 if none
384  *
385  * Send command to NAND device. This is the version for the new large page
386  * devices. We don't have the separate regions as we have in the small page
387  * devices. We must emulate NAND_CMD_READOOB to keep the code compatible.
388  */
nand_command_lp(struct nand_chip * chip,unsigned int command,int column,int page_addr)389 static void nand_command_lp(struct nand_chip *chip, unsigned int command,
390 			    int column, int page_addr)
391 {
392 	struct mtd_info *mtd = nand_to_mtd(chip);
393 
394 	/* Emulate NAND_CMD_READOOB */
395 	if (command == NAND_CMD_READOOB) {
396 		column += mtd->writesize;
397 		command = NAND_CMD_READ0;
398 	}
399 
400 	/* Command latch cycle */
401 	if (command != NAND_CMD_NONE)
402 		chip->legacy.cmd_ctrl(chip, command,
403 				      NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
404 
405 	if (column != -1 || page_addr != -1) {
406 		int ctrl = NAND_CTRL_CHANGE | NAND_NCE | NAND_ALE;
407 
408 		/* Serially input address */
409 		if (column != -1) {
410 			/* Adjust columns for 16 bit buswidth */
411 			if (chip->options & NAND_BUSWIDTH_16 &&
412 					!nand_opcode_8bits(command))
413 				column >>= 1;
414 			chip->legacy.cmd_ctrl(chip, column, ctrl);
415 			ctrl &= ~NAND_CTRL_CHANGE;
416 
417 			/* Only output a single addr cycle for 8bits opcodes. */
418 			if (!nand_opcode_8bits(command))
419 				chip->legacy.cmd_ctrl(chip, column >> 8, ctrl);
420 		}
421 		if (page_addr != -1) {
422 			chip->legacy.cmd_ctrl(chip, page_addr, ctrl);
423 			chip->legacy.cmd_ctrl(chip, page_addr >> 8,
424 					     NAND_NCE | NAND_ALE);
425 			if (chip->options & NAND_ROW_ADDR_3)
426 				chip->legacy.cmd_ctrl(chip, page_addr >> 16,
427 						      NAND_NCE | NAND_ALE);
428 		}
429 	}
430 	chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
431 			      NAND_NCE | NAND_CTRL_CHANGE);
432 
433 	/*
434 	 * Program and erase have their own busy handlers status, sequential
435 	 * in and status need no delay.
436 	 */
437 	switch (command) {
438 
439 	case NAND_CMD_NONE:
440 	case NAND_CMD_CACHEDPROG:
441 	case NAND_CMD_PAGEPROG:
442 	case NAND_CMD_ERASE1:
443 	case NAND_CMD_ERASE2:
444 	case NAND_CMD_SEQIN:
445 	case NAND_CMD_STATUS:
446 	case NAND_CMD_READID:
447 	case NAND_CMD_SET_FEATURES:
448 		return;
449 
450 	case NAND_CMD_RNDIN:
451 		nand_ccs_delay(chip);
452 		return;
453 
454 	case NAND_CMD_RESET:
455 		if (chip->legacy.dev_ready)
456 			break;
457 		udelay(chip->legacy.chip_delay);
458 		chip->legacy.cmd_ctrl(chip, NAND_CMD_STATUS,
459 				      NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
460 		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
461 				      NAND_NCE | NAND_CTRL_CHANGE);
462 		/* EZ-NAND can take upto 250ms as per ONFi v4.0 */
463 		nand_wait_status_ready(chip, 250);
464 		return;
465 
466 	case NAND_CMD_RNDOUT:
467 		/* No ready / busy check necessary */
468 		chip->legacy.cmd_ctrl(chip, NAND_CMD_RNDOUTSTART,
469 				      NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
470 		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
471 				      NAND_NCE | NAND_CTRL_CHANGE);
472 
473 		nand_ccs_delay(chip);
474 		return;
475 
476 	case NAND_CMD_READ0:
477 		/*
478 		 * READ0 is sometimes used to exit GET STATUS mode. When this
479 		 * is the case no address cycles are requested, and we can use
480 		 * this information to detect that READSTART should not be
481 		 * issued.
482 		 */
483 		if (column == -1 && page_addr == -1)
484 			return;
485 
486 		chip->legacy.cmd_ctrl(chip, NAND_CMD_READSTART,
487 				      NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
488 		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
489 				      NAND_NCE | NAND_CTRL_CHANGE);
490 		fallthrough;	/* This applies to read commands */
491 	default:
492 		/*
493 		 * If we don't have access to the busy pin, we apply the given
494 		 * command delay.
495 		 */
496 		if (!chip->legacy.dev_ready) {
497 			udelay(chip->legacy.chip_delay);
498 			return;
499 		}
500 	}
501 
502 	/*
503 	 * Apply this short delay always to ensure that we do wait tWB in
504 	 * any case on any machine.
505 	 */
506 	ndelay(100);
507 
508 	nand_wait_ready(chip);
509 }
510 
511 /**
512  * nand_get_set_features_notsupp - set/get features stub returning -ENOTSUPP
513  * @chip: nand chip info structure
514  * @addr: feature address.
515  * @subfeature_param: the subfeature parameters, a four bytes array.
516  *
517  * Should be used by NAND controller drivers that do not support the SET/GET
518  * FEATURES operations.
519  */
nand_get_set_features_notsupp(struct nand_chip * chip,int addr,u8 * subfeature_param)520 int nand_get_set_features_notsupp(struct nand_chip *chip, int addr,
521 				  u8 *subfeature_param)
522 {
523 	return -ENOTSUPP;
524 }
525 EXPORT_SYMBOL(nand_get_set_features_notsupp);
526 
527 /**
528  * nand_wait - [DEFAULT] wait until the command is done
529  * @chip: NAND chip structure
530  *
531  * Wait for command done. This applies to erase and program only.
532  */
nand_wait(struct nand_chip * chip)533 static int nand_wait(struct nand_chip *chip)
534 {
535 	struct mtd_info *mtd = nand_to_mtd(chip);
536 	unsigned long timeo = 400;
537 	u8 status;
538 	int ret;
539 
540 	/*
541 	 * Apply this short delay always to ensure that we do wait tWB in any
542 	 * case on any machine.
543 	 */
544 	ndelay(100);
545 
546 	ret = nand_status_op(chip, NULL);
547 	if (ret)
548 		return ret;
549 
550 	if (mtd->oops_panic_write) {
551 		panic_nand_wait(chip, timeo);
552 	} else {
553 		timeo = jiffies + msecs_to_jiffies(timeo);
554 		do {
555 			if (chip->legacy.dev_ready) {
556 				if (chip->legacy.dev_ready(chip))
557 					break;
558 			} else {
559 				ret = nand_read_data_op(chip, &status,
560 							sizeof(status), true,
561 							false);
562 				if (ret)
563 					return ret;
564 
565 				if (status & NAND_STATUS_READY)
566 					break;
567 			}
568 			cond_resched();
569 		} while (time_before(jiffies, timeo));
570 	}
571 
572 	ret = nand_read_data_op(chip, &status, sizeof(status), true, false);
573 	if (ret)
574 		return ret;
575 
576 	/* This can happen if in case of timeout or buggy dev_ready */
577 	WARN_ON(!(status & NAND_STATUS_READY));
578 	return status;
579 }
580 
nand_legacy_set_defaults(struct nand_chip * chip)581 void nand_legacy_set_defaults(struct nand_chip *chip)
582 {
583 	unsigned int busw = chip->options & NAND_BUSWIDTH_16;
584 
585 	if (nand_has_exec_op(chip))
586 		return;
587 
588 	/* check for proper chip_delay setup, set 20us if not */
589 	if (!chip->legacy.chip_delay)
590 		chip->legacy.chip_delay = 20;
591 
592 	/* check, if a user supplied command function given */
593 	if (!chip->legacy.cmdfunc)
594 		chip->legacy.cmdfunc = nand_command;
595 
596 	/* check, if a user supplied wait function given */
597 	if (chip->legacy.waitfunc == NULL)
598 		chip->legacy.waitfunc = nand_wait;
599 
600 	if (!chip->legacy.select_chip)
601 		chip->legacy.select_chip = nand_select_chip;
602 
603 	/* If called twice, pointers that depend on busw may need to be reset */
604 	if (!chip->legacy.read_byte || chip->legacy.read_byte == nand_read_byte)
605 		chip->legacy.read_byte = busw ? nand_read_byte16 : nand_read_byte;
606 	if (!chip->legacy.write_buf || chip->legacy.write_buf == nand_write_buf)
607 		chip->legacy.write_buf = busw ? nand_write_buf16 : nand_write_buf;
608 	if (!chip->legacy.write_byte || chip->legacy.write_byte == nand_write_byte)
609 		chip->legacy.write_byte = busw ? nand_write_byte16 : nand_write_byte;
610 	if (!chip->legacy.read_buf || chip->legacy.read_buf == nand_read_buf)
611 		chip->legacy.read_buf = busw ? nand_read_buf16 : nand_read_buf;
612 }
613 
nand_legacy_adjust_cmdfunc(struct nand_chip * chip)614 void nand_legacy_adjust_cmdfunc(struct nand_chip *chip)
615 {
616 	struct mtd_info *mtd = nand_to_mtd(chip);
617 
618 	/* Do not replace user supplied command function! */
619 	if (mtd->writesize > 512 && chip->legacy.cmdfunc == nand_command)
620 		chip->legacy.cmdfunc = nand_command_lp;
621 }
622 
nand_legacy_check_hooks(struct nand_chip * chip)623 int nand_legacy_check_hooks(struct nand_chip *chip)
624 {
625 	/*
626 	 * ->legacy.cmdfunc() is legacy and will only be used if ->exec_op() is
627 	 * not populated.
628 	 */
629 	if (nand_has_exec_op(chip))
630 		return 0;
631 
632 	/*
633 	 * Default functions assigned for ->legacy.cmdfunc() and
634 	 * ->legacy.select_chip() both expect ->legacy.cmd_ctrl() to be
635 	 *  populated.
636 	 */
637 	if ((!chip->legacy.cmdfunc || !chip->legacy.select_chip) &&
638 	    !chip->legacy.cmd_ctrl) {
639 		pr_err("->legacy.cmd_ctrl() should be provided\n");
640 		return -EINVAL;
641 	}
642 
643 	return 0;
644 }
645