mtd: rawnand: Move legacy code to nand_legacy.c

Allows us to move a few hundred lines of deprecated code out of the
core file which is quite big.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

drivers/mtd/nand/raw/Makefile

@@ -57,7 +57,7 @@ obj-$(CONFIG_MTD_NAND_QCOM)		+= qcom_nandc.o
 obj-$(CONFIG_MTD_NAND_MTK)		+= mtk_ecc.o mtk_nand.o
 obj-$(CONFIG_MTD_NAND_TEGRA)		+= tegra_nand.o
 
-nand-objs := nand_base.o nand_bbt.o nand_timings.o nand_ids.o
+nand-objs := nand_base.o nand_legacy.o nand_bbt.o nand_timings.o nand_ids.o
 nand-objs += nand_amd.o
 nand-objs += nand_hynix.o
 nand-objs += nand_macronix.o

drivers/mtd/nand/raw/internals.h

@@ -89,10 +89,16 @@ int nand_write_page_raw_notsupp(struct nand_chip *chip, const u8 *buf,
 				int oob_required, int page);
 int nand_exit_status_op(struct nand_chip *chip);
 void nand_decode_ext_id(struct nand_chip *chip);
+void panic_nand_wait(struct nand_chip *chip, unsigned long timeo);
 
 /* BBT functions */
 int nand_markbad_bbt(struct nand_chip *chip, loff_t offs);
 int nand_isreserved_bbt(struct nand_chip *chip, loff_t offs);
 int nand_isbad_bbt(struct nand_chip *chip, loff_t offs, int allowbbt);
 
+/* Legacy */
+void nand_legacy_set_defaults(struct nand_chip *chip);
+void nand_legacy_adjust_cmdfunc(struct nand_chip *chip);
+int nand_legacy_check_hooks(struct nand_chip *chip);
+
 #endif /* __LINUX_RAWNAND_INTERNALS */

drivers/mtd/nand/raw/nand_base.c

@@ -36,7 +36,6 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
-#include <linux/nmi.h>
 #include <linux/types.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/nand_ecc.h>
@@ -253,150 +252,6 @@ static void nand_release_device(struct mtd_info *mtd)
 	spin_unlock(&chip->controller->lock);
 }
 
-/**
- * nand_read_byte - [DEFAULT] read one byte from the chip
- * @chip: NAND chip object
- *
- * Default read function for 8bit buswidth
- */
-static uint8_t nand_read_byte(struct nand_chip *chip)
-{
-	return readb(chip->legacy.IO_ADDR_R);
-}
-
-/**
- * nand_read_byte16 - [DEFAULT] read one byte endianness aware from the chip
- * @chip: NAND chip object
- *
- * Default read function for 16bit buswidth with endianness conversion.
- *
- */
-static uint8_t nand_read_byte16(struct nand_chip *chip)
-{
-	return (uint8_t) cpu_to_le16(readw(chip->legacy.IO_ADDR_R));
-}
-
-/**
- * nand_select_chip - [DEFAULT] control CE line
- * @chip: NAND chip object
- * @chipnr: chipnumber to select, -1 for deselect
- *
- * Default select function for 1 chip devices.
- */
-static void nand_select_chip(struct nand_chip *chip, int chipnr)
-{
-	switch (chipnr) {
-	case -1:
-		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
-				      0 | NAND_CTRL_CHANGE);
-		break;
-	case 0:
-		break;
-
-	default:
-		BUG();
-	}
-}
-
-/**
- * nand_write_byte - [DEFAULT] write single byte to chip
- * @chip: NAND chip object
- * @byte: value to write
- *
- * Default function to write a byte to I/O[7:0]
- */
-static void nand_write_byte(struct nand_chip *chip, uint8_t byte)
-{
-	chip->legacy.write_buf(chip, &byte, 1);
-}
-
-/**
- * nand_write_byte16 - [DEFAULT] write single byte to a chip with width 16
- * @chip: NAND chip object
- * @byte: value to write
- *
- * Default function to write a byte to I/O[7:0] on a 16-bit wide chip.
- */
-static void nand_write_byte16(struct nand_chip *chip, uint8_t byte)
-{
-	uint16_t word = byte;
-
-	/*
-	 * It's not entirely clear what should happen to I/O[15:8] when writing
-	 * a byte. The ONFi spec (Revision 3.1; 2012-09-19, Section 2.16) reads:
-	 *
-	 *    When the host supports a 16-bit bus width, only data is
-	 *    transferred at the 16-bit width. All address and command line
-	 *    transfers shall use only the lower 8-bits of the data bus. During
-	 *    command transfers, the host may place any value on the upper
-	 *    8-bits of the data bus. During address transfers, the host shall
-	 *    set the upper 8-bits of the data bus to 00h.
-	 *
-	 * One user of the write_byte callback is nand_set_features. The
-	 * four parameters are specified to be written to I/O[7:0], but this is
-	 * neither an address nor a command transfer. Let's assume a 0 on the
-	 * upper I/O lines is OK.
-	 */
-	chip->legacy.write_buf(chip, (uint8_t *)&word, 2);
-}
-
-/**
- * nand_write_buf - [DEFAULT] write buffer to chip
- * @chip: NAND chip object
- * @buf: data buffer
- * @len: number of bytes to write
- *
- * Default write function for 8bit buswidth.
- */
-static void nand_write_buf(struct nand_chip *chip, const uint8_t *buf, int len)
-{
-	iowrite8_rep(chip->legacy.IO_ADDR_W, buf, len);
-}
-
-/**
- * nand_read_buf - [DEFAULT] read chip data into buffer
- * @chip: NAND chip object
- * @buf: buffer to store date
- * @len: number of bytes to read
- *
- * Default read function for 8bit buswidth.
- */
-static void nand_read_buf(struct nand_chip *chip, uint8_t *buf, int len)
-{
-	ioread8_rep(chip->legacy.IO_ADDR_R, buf, len);
-}
-
-/**
- * nand_write_buf16 - [DEFAULT] write buffer to chip
- * @chip: NAND chip object
- * @buf: data buffer
- * @len: number of bytes to write
- *
- * Default write function for 16bit buswidth.
- */
-static void nand_write_buf16(struct nand_chip *chip, const uint8_t *buf,
-			     int len)
-{
-	u16 *p = (u16 *) buf;
-
-	iowrite16_rep(chip->legacy.IO_ADDR_W, p, len >> 1);
-}
-
-/**
- * nand_read_buf16 - [DEFAULT] read chip data into buffer
- * @chip: NAND chip object
- * @buf: buffer to store date
- * @len: number of bytes to read
- *
- * Default read function for 16bit buswidth.
- */
-static void nand_read_buf16(struct nand_chip *chip, uint8_t *buf, int len)
-{
-	u16 *p = (u16 *) buf;
-
-	ioread16_rep(chip->legacy.IO_ADDR_R, p, len >> 1);
-}
-
 /**
  * nand_block_bad - [DEFAULT] Read bad block marker from the chip
  * @chip: NAND chip object
@@ -611,81 +466,6 @@ static int nand_block_checkbad(struct mtd_info *mtd, loff_t ofs, int allowbbt)
 	return nand_isbad_bbm(chip, ofs);
 }
 
-/**
- * panic_nand_wait_ready - [GENERIC] Wait for the ready pin after commands.
- * @mtd: MTD device structure
- * @timeo: Timeout
- *
- * Helper function for nand_wait_ready used when needing to wait in interrupt
- * context.
- */
-static void panic_nand_wait_ready(struct mtd_info *mtd, unsigned long timeo)
-{
-	struct nand_chip *chip = mtd_to_nand(mtd);
-	int i;
-
-	/* Wait for the device to get ready */
-	for (i = 0; i < timeo; i++) {
-		if (chip->legacy.dev_ready(chip))
-			break;
-		touch_softlockup_watchdog();
-		mdelay(1);
-	}
-}
-
-/**
- * nand_wait_ready - [GENERIC] Wait for the ready pin after commands.
- * @chip: NAND chip object
- *
- * Wait for the ready pin after a command, and warn if a timeout occurs.
- */
-void nand_wait_ready(struct nand_chip *chip)
-{
-	struct mtd_info *mtd = nand_to_mtd(chip);
-	unsigned long timeo = 400;
-
-	if (in_interrupt() || oops_in_progress)
-		return panic_nand_wait_ready(mtd, timeo);
-
-	/* Wait until command is processed or timeout occurs */
-	timeo = jiffies + msecs_to_jiffies(timeo);
-	do {
-		if (chip->legacy.dev_ready(chip))
-			return;
-		cond_resched();
-	} while (time_before(jiffies, timeo));
-
-	if (!chip->legacy.dev_ready(chip))
-		pr_warn_ratelimited("timeout while waiting for chip to become ready\n");
-}
-EXPORT_SYMBOL_GPL(nand_wait_ready);
-
-/**
- * nand_wait_status_ready - [GENERIC] Wait for the ready status after commands.
- * @mtd: MTD device structure
- * @timeo: Timeout in ms
- *
- * Wait for status ready (i.e. command done) or timeout.
- */
-static void nand_wait_status_ready(struct mtd_info *mtd, unsigned long timeo)
-{
-	register struct nand_chip *chip = mtd_to_nand(mtd);
-	int ret;
-
-	timeo = jiffies + msecs_to_jiffies(timeo);
-	do {
-		u8 status;
-
-		ret = nand_read_data_op(chip, &status, sizeof(status), true);
-		if (ret)
-			return;
-
-		if (status & NAND_STATUS_READY)
-			break;
-		touch_softlockup_watchdog();
-	} while (time_before(jiffies, timeo));
-};
-
 /**
  * nand_soft_waitrdy - Poll STATUS reg until RDY bit is set to 1
  * @chip: NAND chip structure
@@ -751,275 +531,6 @@ int nand_soft_waitrdy(struct nand_chip *chip, unsigned long timeout_ms)
 };
 EXPORT_SYMBOL_GPL(nand_soft_waitrdy);
 
-/**
- * nand_command - [DEFAULT] Send command to NAND device
- * @chip: NAND chip object
- * @command: the command to be sent
- * @column: the column address for this command, -1 if none
- * @page_addr: the page address for this command, -1 if none
- *
- * Send command to NAND device. This function is used for small page devices
- * (512 Bytes per page).
- */
-static void nand_command(struct nand_chip *chip, unsigned int command,
-			 int column, int page_addr)
-{
-	struct mtd_info *mtd = nand_to_mtd(chip);
-	int ctrl = NAND_CTRL_CLE | NAND_CTRL_CHANGE;
-
-	/* Write out the command to the device */
-	if (command == NAND_CMD_SEQIN) {
-		int readcmd;
-
-		if (column >= mtd->writesize) {
-			/* OOB area */
-			column -= mtd->writesize;
-			readcmd = NAND_CMD_READOOB;
-		} else if (column < 256) {
-			/* First 256 bytes --> READ0 */
-			readcmd = NAND_CMD_READ0;
-		} else {
-			column -= 256;
-			readcmd = NAND_CMD_READ1;
-		}
-		chip->legacy.cmd_ctrl(chip, readcmd, ctrl);
-		ctrl &= ~NAND_CTRL_CHANGE;
-	}
-	if (command != NAND_CMD_NONE)
-		chip->legacy.cmd_ctrl(chip, command, ctrl);
-
-	/* Address cycle, when necessary */
-	ctrl = NAND_CTRL_ALE | NAND_CTRL_CHANGE;
-	/* Serially input address */
-	if (column != -1) {
-		/* Adjust columns for 16 bit buswidth */
-		if (chip->options & NAND_BUSWIDTH_16 &&
-				!nand_opcode_8bits(command))
-			column >>= 1;
-		chip->legacy.cmd_ctrl(chip, column, ctrl);
-		ctrl &= ~NAND_CTRL_CHANGE;
-	}
-	if (page_addr != -1) {
-		chip->legacy.cmd_ctrl(chip, page_addr, ctrl);
-		ctrl &= ~NAND_CTRL_CHANGE;
-		chip->legacy.cmd_ctrl(chip, page_addr >> 8, ctrl);
-		if (chip->options & NAND_ROW_ADDR_3)
-			chip->legacy.cmd_ctrl(chip, page_addr >> 16, ctrl);
-	}
-	chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
-			      NAND_NCE | NAND_CTRL_CHANGE);
-
-	/*
-	 * Program and erase have their own busy handlers status and sequential
-	 * in needs no delay
-	 */
-	switch (command) {
-
-	case NAND_CMD_NONE:
-	case NAND_CMD_PAGEPROG:
-	case NAND_CMD_ERASE1:
-	case NAND_CMD_ERASE2:
-	case NAND_CMD_SEQIN:
-	case NAND_CMD_STATUS:
-	case NAND_CMD_READID:
-	case NAND_CMD_SET_FEATURES:
-		return;
-
-	case NAND_CMD_RESET:
-		if (chip->legacy.dev_ready)
-			break;
-		udelay(chip->legacy.chip_delay);
-		chip->legacy.cmd_ctrl(chip, NAND_CMD_STATUS,
-				      NAND_CTRL_CLE | NAND_CTRL_CHANGE);
-		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
-				      NAND_NCE | NAND_CTRL_CHANGE);
-		/* EZ-NAND can take upto 250ms as per ONFi v4.0 */
-		nand_wait_status_ready(mtd, 250);
-		return;
-
-		/* This applies to read commands */
-	case NAND_CMD_READ0:
-		/*
-		 * READ0 is sometimes used to exit GET STATUS mode. When this
-		 * is the case no address cycles are requested, and we can use
-		 * this information to detect that we should not wait for the
-		 * device to be ready.
-		 */
-		if (column == -1 && page_addr == -1)
-			return;
-
-	default:
-		/*
-		 * If we don't have access to the busy pin, we apply the given
-		 * command delay
-		 */
-		if (!chip->legacy.dev_ready) {
-			udelay(chip->legacy.chip_delay);
-			return;
-		}
-	}
-	/*
-	 * Apply this short delay always to ensure that we do wait tWB in
-	 * any case on any machine.
-	 */
-	ndelay(100);
-
-	nand_wait_ready(chip);
-}
-
-static void nand_ccs_delay(struct nand_chip *chip)
-{
-	/*
-	 * The controller already takes care of waiting for tCCS when the RNDIN
-	 * or RNDOUT command is sent, return directly.
-	 */
-	if (!(chip->options & NAND_WAIT_TCCS))
-		return;
-
-	/*
-	 * Wait tCCS_min if it is correctly defined, otherwise wait 500ns
-	 * (which should be safe for all NANDs).
-	 */
-	if (chip->setup_data_interface)
-		ndelay(chip->data_interface.timings.sdr.tCCS_min / 1000);
-	else
-		ndelay(500);
-}
-
-/**
- * nand_command_lp - [DEFAULT] Send command to NAND large page device
- * @chip: NAND chip object
- * @command: the command to be sent
- * @column: the column address for this command, -1 if none
- * @page_addr: the page address for this command, -1 if none
- *
- * Send command to NAND device. This is the version for the new large page
- * devices. We don't have the separate regions as we have in the small page
- * devices. We must emulate NAND_CMD_READOOB to keep the code compatible.
- */
-static void nand_command_lp(struct nand_chip *chip, unsigned int command,
-			    int column, int page_addr)
-{
-	struct mtd_info *mtd = nand_to_mtd(chip);
-
-	/* Emulate NAND_CMD_READOOB */
-	if (command == NAND_CMD_READOOB) {
-		column += mtd->writesize;
-		command = NAND_CMD_READ0;
-	}
-
-	/* Command latch cycle */
-	if (command != NAND_CMD_NONE)
-		chip->legacy.cmd_ctrl(chip, command,
-				      NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
-
-	if (column != -1 || page_addr != -1) {
-		int ctrl = NAND_CTRL_CHANGE | NAND_NCE | NAND_ALE;
-
-		/* Serially input address */
-		if (column != -1) {
-			/* Adjust columns for 16 bit buswidth */
-			if (chip->options & NAND_BUSWIDTH_16 &&
-					!nand_opcode_8bits(command))
-				column >>= 1;
-			chip->legacy.cmd_ctrl(chip, column, ctrl);
-			ctrl &= ~NAND_CTRL_CHANGE;
-
-			/* Only output a single addr cycle for 8bits opcodes. */
-			if (!nand_opcode_8bits(command))
-				chip->legacy.cmd_ctrl(chip, column >> 8, ctrl);
-		}
-		if (page_addr != -1) {
-			chip->legacy.cmd_ctrl(chip, page_addr, ctrl);
-			chip->legacy.cmd_ctrl(chip, page_addr >> 8,
-					     NAND_NCE | NAND_ALE);
-			if (chip->options & NAND_ROW_ADDR_3)
-				chip->legacy.cmd_ctrl(chip, page_addr >> 16,
-						      NAND_NCE | NAND_ALE);
-		}
-	}
-	chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
-			      NAND_NCE | NAND_CTRL_CHANGE);
-
-	/*
-	 * Program and erase have their own busy handlers status, sequential
-	 * in and status need no delay.
-	 */
-	switch (command) {
-
-	case NAND_CMD_NONE:
-	case NAND_CMD_CACHEDPROG:
-	case NAND_CMD_PAGEPROG:
-	case NAND_CMD_ERASE1:
-	case NAND_CMD_ERASE2:
-	case NAND_CMD_SEQIN:
-	case NAND_CMD_STATUS:
-	case NAND_CMD_READID:
-	case NAND_CMD_SET_FEATURES:
-		return;
-
-	case NAND_CMD_RNDIN:
-		nand_ccs_delay(chip);
-		return;
-
-	case NAND_CMD_RESET:
-		if (chip->legacy.dev_ready)
-			break;
-		udelay(chip->legacy.chip_delay);
-		chip->legacy.cmd_ctrl(chip, NAND_CMD_STATUS,
-				      NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
-		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
-				      NAND_NCE | NAND_CTRL_CHANGE);
-		/* EZ-NAND can take upto 250ms as per ONFi v4.0 */
-		nand_wait_status_ready(mtd, 250);
-		return;
-
-	case NAND_CMD_RNDOUT:
-		/* No ready / busy check necessary */
-		chip->legacy.cmd_ctrl(chip, NAND_CMD_RNDOUTSTART,
-				      NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
-		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
-				      NAND_NCE | NAND_CTRL_CHANGE);
-
-		nand_ccs_delay(chip);
-		return;
-
-	case NAND_CMD_READ0:
-		/*
-		 * READ0 is sometimes used to exit GET STATUS mode. When this
-		 * is the case no address cycles are requested, and we can use
-		 * this information to detect that READSTART should not be
-		 * issued.
-		 */
-		if (column == -1 && page_addr == -1)
-			return;
-
-		chip->legacy.cmd_ctrl(chip, NAND_CMD_READSTART,
-				      NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
-		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
-				      NAND_NCE | NAND_CTRL_CHANGE);
-
-		/* This applies to read commands */
-	default:
-		/*
-		 * If we don't have access to the busy pin, we apply the given
-		 * command delay.
-		 */
-		if (!chip->legacy.dev_ready) {
-			udelay(chip->legacy.chip_delay);
-			return;
-		}
-	}
-
-	/*
-	 * Apply this short delay always to ensure that we do wait tWB in
-	 * any case on any machine.
-	 */
-	ndelay(100);
-
-	nand_wait_ready(chip);
-}
-
 /**
  * panic_nand_get_device - [GENERIC] Get chip for selected access
  * @chip: the nand chip descriptor
@@ -1087,7 +598,7 @@ retry:
  * we are in interrupt context. May happen when in panic and trying to write
  * an oops through mtdoops.
  */
-static void panic_nand_wait(struct nand_chip *chip, unsigned long timeo)
+void panic_nand_wait(struct nand_chip *chip, unsigned long timeo)
 {
 	int i;
 	for (i = 0; i < timeo; i++) {
@@ -1110,60 +621,6 @@ static void panic_nand_wait(struct nand_chip *chip, unsigned long timeo)
 	}
 }
 
-/**
- * nand_wait - [DEFAULT] wait until the command is done
- * @mtd: MTD device structure
- * @chip: NAND chip structure
- *
- * Wait for command done. This applies to erase and program only.
- */
-static int nand_wait(struct nand_chip *chip)
-{
-
-	unsigned long timeo = 400;
-	u8 status;
-	int ret;
-
-	/*
-	 * Apply this short delay always to ensure that we do wait tWB in any
-	 * case on any machine.
-	 */
-	ndelay(100);
-
-	ret = nand_status_op(chip, NULL);
-	if (ret)
-		return ret;
-
-	if (in_interrupt() || oops_in_progress)
-		panic_nand_wait(chip, timeo);
-	else {
-		timeo = jiffies + msecs_to_jiffies(timeo);
-		do {
-			if (chip->legacy.dev_ready) {
-				if (chip->legacy.dev_ready(chip))
-					break;
-			} else {
-				ret = nand_read_data_op(chip, &status,
-							sizeof(status), true);
-				if (ret)
-					return ret;
-
-				if (status & NAND_STATUS_READY)
-					break;
-			}
-			cond_resched();
-		} while (time_before(jiffies, timeo));
-	}
-
-	ret = nand_read_data_op(chip, &status, sizeof(status), true);
-	if (ret)
-		return ret;
-
-	/* This can happen if in case of timeout or buggy dev_ready */
-	WARN_ON(!(status & NAND_STATUS_READY));
-	return status;
-}
-
 static bool nand_supports_get_features(struct nand_chip *chip, int addr)
 {
 	return (chip->parameters.supports_set_get_features &&
@@ -4864,22 +4321,6 @@ static int nand_max_bad_blocks(struct mtd_info *mtd, loff_t ofs, size_t len)
 	return chip->max_bb_per_die * (part_end_die - part_start_die + 1);
 }
 
-/**
- * nand_get_set_features_notsupp - set/get features stub returning -ENOTSUPP
- * @chip: nand chip info structure
- * @addr: feature address.
- * @subfeature_param: the subfeature parameters, a four bytes array.
- *
- * Should be used by NAND controller drivers that do not support the SET/GET
- * FEATURES operations.
- */
-int nand_get_set_features_notsupp(struct nand_chip *chip, int addr,
-				  u8 *subfeature_param)
-{
-	return -ENOTSUPP;
-}
-EXPORT_SYMBOL(nand_get_set_features_notsupp);
-
 /**
  * nand_suspend - [MTD Interface] Suspend the NAND flash
  * @mtd: MTD device structure
@@ -4917,32 +4358,7 @@ static void nand_shutdown(struct mtd_info *mtd)
 /* Set default functions */
 static void nand_set_defaults(struct nand_chip *chip)
 {
-	unsigned int busw = chip->options & NAND_BUSWIDTH_16;
-
-	/* check for proper chip_delay setup, set 20us if not */
-	if (!chip->legacy.chip_delay)
-		chip->legacy.chip_delay = 20;
-
-	/* check, if a user supplied command function given */
-	if (!chip->legacy.cmdfunc && !chip->exec_op)
-		chip->legacy.cmdfunc = nand_command;
-
-	/* check, if a user supplied wait function given */
-	if (chip->legacy.waitfunc == NULL)
-		chip->legacy.waitfunc = nand_wait;
-
-	if (!chip->select_chip)
-		chip->select_chip = nand_select_chip;
-
-	/* If called twice, pointers that depend on busw may need to be reset */
-	if (!chip->legacy.read_byte || chip->legacy.read_byte == nand_read_byte)
-		chip->legacy.read_byte = busw ? nand_read_byte16 : nand_read_byte;
-	if (!chip->legacy.write_buf || chip->legacy.write_buf == nand_write_buf)
-		chip->legacy.write_buf = busw ? nand_write_buf16 : nand_write_buf;
-	if (!chip->legacy.write_byte || chip->legacy.write_byte == nand_write_byte)
-		chip->legacy.write_byte = busw ? nand_write_byte16 : nand_write_byte;
-	if (!chip->legacy.read_buf || chip->legacy.read_buf == nand_read_buf)
-		chip->legacy.read_buf = busw ? nand_read_buf16 : nand_read_buf;
+	nand_legacy_set_defaults(chip);
 
 	if (!chip->controller) {
 		chip->controller = &chip->dummy_controller;
@@ -5212,9 +4628,7 @@ static int nand_flash_detect_onfi(struct nand_chip *chip)
 		 * chip->legacy.cmdfunc now. We do not replace user supplied
 		 * command function.
 		 */
-		if (mtd->writesize > 512 &&
-		    chip->legacy.cmdfunc == nand_command)
-			chip->legacy.cmdfunc = nand_command_lp;
+		nand_legacy_adjust_cmdfunc(chip);
 
 		/* The Extended Parameter Page is supported since ONFI 2.1. */
 		if (nand_flash_detect_ext_param_page(chip, p))
@@ -5737,9 +5151,7 @@ ident_done:
 
 	chip->badblockbits = 8;
 
-	/* Do not replace user supplied command function! */
-	if (mtd->writesize > 512 && chip->legacy.cmdfunc == nand_command)
-		chip->legacy.cmdfunc = nand_command_lp;
+	nand_legacy_adjust_cmdfunc(chip);
 
 	pr_info("device found, Manufacturer ID: 0x%02x, Chip ID: 0x%02x\n",
 		maf_id, dev_id);
@@ -5935,23 +5347,15 @@ static int nand_scan_ident(struct nand_chip *chip, unsigned int maxchips,
 	if (!mtd->name && mtd->dev.parent)
 		mtd->name = dev_name(mtd->dev.parent);
 
-	/*
-	 * ->legacy.cmdfunc() is legacy and will only be used if ->exec_op() is
-	 * not populated.
-	 */
-	if (!chip->exec_op) {
-		/*
-		 * Default functions assigned for ->legacy.cmdfunc() and
-		 * ->select_chip() both expect ->legacy.cmd_ctrl() to be
-		 *  populated.
-		 */
-		if ((!chip->legacy.cmdfunc || !chip->select_chip) &&
-		    !chip->legacy.cmd_ctrl) {
-			pr_err("->legacy.cmd_ctrl() should be provided\n");
-			return -EINVAL;
-		}
+	if (chip->exec_op && !chip->select_chip) {
+		pr_err("->select_chip() is mandatory when implementing ->exec_op()\n");
+		return -EINVAL;
 	}
 
+	ret = nand_legacy_check_hooks(chip);
+	if (ret)
+		return ret;
+
 	/* Set the default functions */
 	nand_set_defaults(chip);
 

drivers/mtd/nand/raw/nand_legacy.c

@@ -0,0 +1,642 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright (C) 2000 Steven J. Hill (sjhill@realitydiluted.com)
+ *		  2002-2006 Thomas Gleixner (tglx@linutronix.de)
+ *
+ *  Credits:
+ *	David Woodhouse for adding multichip support
+ *
+ *	Aleph One Ltd. and Toby Churchill Ltd. for supporting the
+ *	rework for 2K page size chips
+ *
+ * This file contains all legacy helpers/code that should be removed
+ * at some point.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/nmi.h>
+
+#include "internals.h"
+
+/**
+ * nand_read_byte - [DEFAULT] read one byte from the chip
+ * @chip: NAND chip object
+ *
+ * Default read function for 8bit buswidth
+ */
+static uint8_t nand_read_byte(struct nand_chip *chip)
+{
+	return readb(chip->legacy.IO_ADDR_R);
+}
+
+/**
+ * nand_read_byte16 - [DEFAULT] read one byte endianness aware from the chip
+ * @chip: NAND chip object
+ *
+ * Default read function for 16bit buswidth with endianness conversion.
+ *
+ */
+static uint8_t nand_read_byte16(struct nand_chip *chip)
+{
+	return (uint8_t) cpu_to_le16(readw(chip->legacy.IO_ADDR_R));
+}
+
+/**
+ * nand_select_chip - [DEFAULT] control CE line
+ * @chip: NAND chip object
+ * @chipnr: chipnumber to select, -1 for deselect
+ *
+ * Default select function for 1 chip devices.
+ */
+static void nand_select_chip(struct nand_chip *chip, int chipnr)
+{
+	switch (chipnr) {
+	case -1:
+		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
+				      0 | NAND_CTRL_CHANGE);
+		break;
+	case 0:
+		break;
+
+	default:
+		BUG();
+	}
+}
+
+/**
+ * nand_write_byte - [DEFAULT] write single byte to chip
+ * @chip: NAND chip object
+ * @byte: value to write
+ *
+ * Default function to write a byte to I/O[7:0]
+ */
+static void nand_write_byte(struct nand_chip *chip, uint8_t byte)
+{
+	chip->legacy.write_buf(chip, &byte, 1);
+}
+
+/**
+ * nand_write_byte16 - [DEFAULT] write single byte to a chip with width 16
+ * @chip: NAND chip object
+ * @byte: value to write
+ *
+ * Default function to write a byte to I/O[7:0] on a 16-bit wide chip.
+ */
+static void nand_write_byte16(struct nand_chip *chip, uint8_t byte)
+{
+	uint16_t word = byte;
+
+	/*
+	 * It's not entirely clear what should happen to I/O[15:8] when writing
+	 * a byte. The ONFi spec (Revision 3.1; 2012-09-19, Section 2.16) reads:
+	 *
+	 *    When the host supports a 16-bit bus width, only data is
+	 *    transferred at the 16-bit width. All address and command line
+	 *    transfers shall use only the lower 8-bits of the data bus. During
+	 *    command transfers, the host may place any value on the upper
+	 *    8-bits of the data bus. During address transfers, the host shall
+	 *    set the upper 8-bits of the data bus to 00h.
+	 *
+	 * One user of the write_byte callback is nand_set_features. The
+	 * four parameters are specified to be written to I/O[7:0], but this is
+	 * neither an address nor a command transfer. Let's assume a 0 on the
+	 * upper I/O lines is OK.
+	 */
+	chip->legacy.write_buf(chip, (uint8_t *)&word, 2);
+}
+
+/**
+ * nand_write_buf - [DEFAULT] write buffer to chip
+ * @chip: NAND chip object
+ * @buf: data buffer
+ * @len: number of bytes to write
+ *
+ * Default write function for 8bit buswidth.
+ */
+static void nand_write_buf(struct nand_chip *chip, const uint8_t *buf, int len)
+{
+	iowrite8_rep(chip->legacy.IO_ADDR_W, buf, len);
+}
+
+/**
+ * nand_read_buf - [DEFAULT] read chip data into buffer
+ * @chip: NAND chip object
+ * @buf: buffer to store date
+ * @len: number of bytes to read
+ *
+ * Default read function for 8bit buswidth.
+ */
+static void nand_read_buf(struct nand_chip *chip, uint8_t *buf, int len)
+{
+	ioread8_rep(chip->legacy.IO_ADDR_R, buf, len);
+}
+
+/**
+ * nand_write_buf16 - [DEFAULT] write buffer to chip
+ * @chip: NAND chip object
+ * @buf: data buffer
+ * @len: number of bytes to write
+ *
+ * Default write function for 16bit buswidth.
+ */
+static void nand_write_buf16(struct nand_chip *chip, const uint8_t *buf,
+			     int len)
+{
+	u16 *p = (u16 *) buf;
+
+	iowrite16_rep(chip->legacy.IO_ADDR_W, p, len >> 1);
+}
+
+/**
+ * nand_read_buf16 - [DEFAULT] read chip data into buffer
+ * @chip: NAND chip object
+ * @buf: buffer to store date
+ * @len: number of bytes to read
+ *
+ * Default read function for 16bit buswidth.
+ */
+static void nand_read_buf16(struct nand_chip *chip, uint8_t *buf, int len)
+{
+	u16 *p = (u16 *) buf;
+
+	ioread16_rep(chip->legacy.IO_ADDR_R, p, len >> 1);
+}
+
+/**
+ * panic_nand_wait_ready - [GENERIC] Wait for the ready pin after commands.
+ * @mtd: MTD device structure
+ * @timeo: Timeout
+ *
+ * Helper function for nand_wait_ready used when needing to wait in interrupt
+ * context.
+ */
+static void panic_nand_wait_ready(struct mtd_info *mtd, unsigned long timeo)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	int i;
+
+	/* Wait for the device to get ready */
+	for (i = 0; i < timeo; i++) {
+		if (chip->legacy.dev_ready(chip))
+			break;
+		touch_softlockup_watchdog();
+		mdelay(1);
+	}
+}
+
+/**
+ * nand_wait_ready - [GENERIC] Wait for the ready pin after commands.
+ * @chip: NAND chip object
+ *
+ * Wait for the ready pin after a command, and warn if a timeout occurs.
+ */
+void nand_wait_ready(struct nand_chip *chip)
+{
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	unsigned long timeo = 400;
+
+	if (in_interrupt() || oops_in_progress)
+		return panic_nand_wait_ready(mtd, timeo);
+
+	/* Wait until command is processed or timeout occurs */
+	timeo = jiffies + msecs_to_jiffies(timeo);
+	do {
+		if (chip->legacy.dev_ready(chip))
+			return;
+		cond_resched();
+	} while (time_before(jiffies, timeo));
+
+	if (!chip->legacy.dev_ready(chip))
+		pr_warn_ratelimited("timeout while waiting for chip to become ready\n");
+}
+EXPORT_SYMBOL_GPL(nand_wait_ready);
+
+/**
+ * nand_wait_status_ready - [GENERIC] Wait for the ready status after commands.
+ * @mtd: MTD device structure
+ * @timeo: Timeout in ms
+ *
+ * Wait for status ready (i.e. command done) or timeout.
+ */
+static void nand_wait_status_ready(struct mtd_info *mtd, unsigned long timeo)
+{
+	register struct nand_chip *chip = mtd_to_nand(mtd);
+	int ret;
+
+	timeo = jiffies + msecs_to_jiffies(timeo);
+	do {
+		u8 status;
+
+		ret = nand_read_data_op(chip, &status, sizeof(status), true);
+		if (ret)
+			return;
+
+		if (status & NAND_STATUS_READY)
+			break;
+		touch_softlockup_watchdog();
+	} while (time_before(jiffies, timeo));
+};
+
+/**
+ * nand_command - [DEFAULT] Send command to NAND device
+ * @chip: NAND chip object
+ * @command: the command to be sent
+ * @column: the column address for this command, -1 if none
+ * @page_addr: the page address for this command, -1 if none
+ *
+ * Send command to NAND device. This function is used for small page devices
+ * (512 Bytes per page).
+ */
+static void nand_command(struct nand_chip *chip, unsigned int command,
+			 int column, int page_addr)
+{
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	int ctrl = NAND_CTRL_CLE | NAND_CTRL_CHANGE;
+
+	/* Write out the command to the device */
+	if (command == NAND_CMD_SEQIN) {
+		int readcmd;
+
+		if (column >= mtd->writesize) {
+			/* OOB area */
+			column -= mtd->writesize;
+			readcmd = NAND_CMD_READOOB;
+		} else if (column < 256) {
+			/* First 256 bytes --> READ0 */
+			readcmd = NAND_CMD_READ0;
+		} else {
+			column -= 256;
+			readcmd = NAND_CMD_READ1;
+		}
+		chip->legacy.cmd_ctrl(chip, readcmd, ctrl);
+		ctrl &= ~NAND_CTRL_CHANGE;
+	}
+	if (command != NAND_CMD_NONE)
+		chip->legacy.cmd_ctrl(chip, command, ctrl);
+
+	/* Address cycle, when necessary */
+	ctrl = NAND_CTRL_ALE | NAND_CTRL_CHANGE;
+	/* Serially input address */
+	if (column != -1) {
+		/* Adjust columns for 16 bit buswidth */
+		if (chip->options & NAND_BUSWIDTH_16 &&
+				!nand_opcode_8bits(command))
+			column >>= 1;
+		chip->legacy.cmd_ctrl(chip, column, ctrl);
+		ctrl &= ~NAND_CTRL_CHANGE;
+	}
+	if (page_addr != -1) {
+		chip->legacy.cmd_ctrl(chip, page_addr, ctrl);
+		ctrl &= ~NAND_CTRL_CHANGE;
+		chip->legacy.cmd_ctrl(chip, page_addr >> 8, ctrl);
+		if (chip->options & NAND_ROW_ADDR_3)
+			chip->legacy.cmd_ctrl(chip, page_addr >> 16, ctrl);
+	}
+	chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
+			      NAND_NCE | NAND_CTRL_CHANGE);
+
+	/*
+	 * Program and erase have their own busy handlers status and sequential
+	 * in needs no delay
+	 */
+	switch (command) {
+
+	case NAND_CMD_NONE:
+	case NAND_CMD_PAGEPROG:
+	case NAND_CMD_ERASE1:
+	case NAND_CMD_ERASE2:
+	case NAND_CMD_SEQIN:
+	case NAND_CMD_STATUS:
+	case NAND_CMD_READID:
+	case NAND_CMD_SET_FEATURES:
+		return;
+
+	case NAND_CMD_RESET:
+		if (chip->legacy.dev_ready)
+			break;
+		udelay(chip->legacy.chip_delay);
+		chip->legacy.cmd_ctrl(chip, NAND_CMD_STATUS,
+				      NAND_CTRL_CLE | NAND_CTRL_CHANGE);
+		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
+				      NAND_NCE | NAND_CTRL_CHANGE);
+		/* EZ-NAND can take upto 250ms as per ONFi v4.0 */
+		nand_wait_status_ready(mtd, 250);
+		return;
+
+		/* This applies to read commands */
+	case NAND_CMD_READ0:
+		/*
+		 * READ0 is sometimes used to exit GET STATUS mode. When this
+		 * is the case no address cycles are requested, and we can use
+		 * this information to detect that we should not wait for the
+		 * device to be ready.
+		 */
+		if (column == -1 && page_addr == -1)
+			return;
+
+	default:
+		/*
+		 * If we don't have access to the busy pin, we apply the given
+		 * command delay
+		 */
+		if (!chip->legacy.dev_ready) {
+			udelay(chip->legacy.chip_delay);
+			return;
+		}
+	}
+	/*
+	 * Apply this short delay always to ensure that we do wait tWB in
+	 * any case on any machine.
+	 */
+	ndelay(100);
+
+	nand_wait_ready(chip);
+}
+
+static void nand_ccs_delay(struct nand_chip *chip)
+{
+	/*
+	 * The controller already takes care of waiting for tCCS when the RNDIN
+	 * or RNDOUT command is sent, return directly.
+	 */
+	if (!(chip->options & NAND_WAIT_TCCS))
+		return;
+
+	/*
+	 * Wait tCCS_min if it is correctly defined, otherwise wait 500ns
+	 * (which should be safe for all NANDs).
+	 */
+	if (chip->setup_data_interface)
+		ndelay(chip->data_interface.timings.sdr.tCCS_min / 1000);
+	else
+		ndelay(500);
+}
+
+/**
+ * nand_command_lp - [DEFAULT] Send command to NAND large page device
+ * @chip: NAND chip object
+ * @command: the command to be sent
+ * @column: the column address for this command, -1 if none
+ * @page_addr: the page address for this command, -1 if none
+ *
+ * Send command to NAND device. This is the version for the new large page
+ * devices. We don't have the separate regions as we have in the small page
+ * devices. We must emulate NAND_CMD_READOOB to keep the code compatible.
+ */
+static void nand_command_lp(struct nand_chip *chip, unsigned int command,
+			    int column, int page_addr)
+{
+	struct mtd_info *mtd = nand_to_mtd(chip);
+
+	/* Emulate NAND_CMD_READOOB */
+	if (command == NAND_CMD_READOOB) {
+		column += mtd->writesize;
+		command = NAND_CMD_READ0;
+	}
+
+	/* Command latch cycle */
+	if (command != NAND_CMD_NONE)
+		chip->legacy.cmd_ctrl(chip, command,
+				      NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
+
+	if (column != -1 || page_addr != -1) {
+		int ctrl = NAND_CTRL_CHANGE | NAND_NCE | NAND_ALE;
+
+		/* Serially input address */
+		if (column != -1) {
+			/* Adjust columns for 16 bit buswidth */
+			if (chip->options & NAND_BUSWIDTH_16 &&
+					!nand_opcode_8bits(command))
+				column >>= 1;
+			chip->legacy.cmd_ctrl(chip, column, ctrl);
+			ctrl &= ~NAND_CTRL_CHANGE;
+
+			/* Only output a single addr cycle for 8bits opcodes. */
+			if (!nand_opcode_8bits(command))
+				chip->legacy.cmd_ctrl(chip, column >> 8, ctrl);
+		}
+		if (page_addr != -1) {
+			chip->legacy.cmd_ctrl(chip, page_addr, ctrl);
+			chip->legacy.cmd_ctrl(chip, page_addr >> 8,
+					     NAND_NCE | NAND_ALE);
+			if (chip->options & NAND_ROW_ADDR_3)
+				chip->legacy.cmd_ctrl(chip, page_addr >> 16,
+						      NAND_NCE | NAND_ALE);
+		}
+	}
+	chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
+			      NAND_NCE | NAND_CTRL_CHANGE);
+
+	/*
+	 * Program and erase have their own busy handlers status, sequential
+	 * in and status need no delay.
+	 */
+	switch (command) {
+
+	case NAND_CMD_NONE:
+	case NAND_CMD_CACHEDPROG:
+	case NAND_CMD_PAGEPROG:
+	case NAND_CMD_ERASE1:
+	case NAND_CMD_ERASE2:
+	case NAND_CMD_SEQIN:
+	case NAND_CMD_STATUS:
+	case NAND_CMD_READID:
+	case NAND_CMD_SET_FEATURES:
+		return;
+
+	case NAND_CMD_RNDIN:
+		nand_ccs_delay(chip);
+		return;
+
+	case NAND_CMD_RESET:
+		if (chip->legacy.dev_ready)
+			break;
+		udelay(chip->legacy.chip_delay);
+		chip->legacy.cmd_ctrl(chip, NAND_CMD_STATUS,
+				      NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
+		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
+				      NAND_NCE | NAND_CTRL_CHANGE);
+		/* EZ-NAND can take upto 250ms as per ONFi v4.0 */
+		nand_wait_status_ready(mtd, 250);
+		return;
+
+	case NAND_CMD_RNDOUT:
+		/* No ready / busy check necessary */
+		chip->legacy.cmd_ctrl(chip, NAND_CMD_RNDOUTSTART,
+				      NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
+		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
+				      NAND_NCE | NAND_CTRL_CHANGE);
+
+		nand_ccs_delay(chip);
+		return;
+
+	case NAND_CMD_READ0:
+		/*
+		 * READ0 is sometimes used to exit GET STATUS mode. When this
+		 * is the case no address cycles are requested, and we can use
+		 * this information to detect that READSTART should not be
+		 * issued.
+		 */
+		if (column == -1 && page_addr == -1)
+			return;
+
+		chip->legacy.cmd_ctrl(chip, NAND_CMD_READSTART,
+				      NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
+		chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
+				      NAND_NCE | NAND_CTRL_CHANGE);
+
+		/* This applies to read commands */
+	default:
+		/*
+		 * If we don't have access to the busy pin, we apply the given
+		 * command delay.
+		 */
+		if (!chip->legacy.dev_ready) {
+			udelay(chip->legacy.chip_delay);
+			return;
+		}
+	}
+
+	/*
+	 * Apply this short delay always to ensure that we do wait tWB in
+	 * any case on any machine.
+	 */
+	ndelay(100);
+
+	nand_wait_ready(chip);
+}
+
+/**
+ * nand_get_set_features_notsupp - set/get features stub returning -ENOTSUPP
+ * @chip: nand chip info structure
+ * @addr: feature address.
+ * @subfeature_param: the subfeature parameters, a four bytes array.
+ *
+ * Should be used by NAND controller drivers that do not support the SET/GET
+ * FEATURES operations.
+ */
+int nand_get_set_features_notsupp(struct nand_chip *chip, int addr,
+				  u8 *subfeature_param)
+{
+	return -ENOTSUPP;
+}
+EXPORT_SYMBOL(nand_get_set_features_notsupp);
+
+/**
+ * nand_wait - [DEFAULT] wait until the command is done
+ * @mtd: MTD device structure
+ * @chip: NAND chip structure
+ *
+ * Wait for command done. This applies to erase and program only.
+ */
+static int nand_wait(struct nand_chip *chip)
+{
+
+	unsigned long timeo = 400;
+	u8 status;
+	int ret;
+
+	/*
+	 * Apply this short delay always to ensure that we do wait tWB in any
+	 * case on any machine.
+	 */
+	ndelay(100);
+
+	ret = nand_status_op(chip, NULL);
+	if (ret)
+		return ret;
+
+	if (in_interrupt() || oops_in_progress)
+		panic_nand_wait(chip, timeo);
+	else {
+		timeo = jiffies + msecs_to_jiffies(timeo);
+		do {
+			if (chip->legacy.dev_ready) {
+				if (chip->legacy.dev_ready(chip))
+					break;
+			} else {
+				ret = nand_read_data_op(chip, &status,
+							sizeof(status), true);
+				if (ret)
+					return ret;
+
+				if (status & NAND_STATUS_READY)
+					break;
+			}
+			cond_resched();
+		} while (time_before(jiffies, timeo));
+	}
+
+	ret = nand_read_data_op(chip, &status, sizeof(status), true);
+	if (ret)
+		return ret;
+
+	/* This can happen if in case of timeout or buggy dev_ready */
+	WARN_ON(!(status & NAND_STATUS_READY));
+	return status;
+}
+
+void nand_legacy_set_defaults(struct nand_chip *chip)
+{
+	unsigned int busw = chip->options & NAND_BUSWIDTH_16;
+
+	if (chip->exec_op)
+		return;
+
+	/* check for proper chip_delay setup, set 20us if not */
+	if (!chip->legacy.chip_delay)
+		chip->legacy.chip_delay = 20;
+
+	/* check, if a user supplied command function given */
+	if (!chip->legacy.cmdfunc && !chip->exec_op)
+		chip->legacy.cmdfunc = nand_command;
+
+	/* check, if a user supplied wait function given */
+	if (chip->legacy.waitfunc == NULL)
+		chip->legacy.waitfunc = nand_wait;
+
+	if (!chip->select_chip)
+		chip->select_chip = nand_select_chip;
+
+	/* If called twice, pointers that depend on busw may need to be reset */
+	if (!chip->legacy.read_byte || chip->legacy.read_byte == nand_read_byte)
+		chip->legacy.read_byte = busw ? nand_read_byte16 : nand_read_byte;
+	if (!chip->legacy.write_buf || chip->legacy.write_buf == nand_write_buf)
+		chip->legacy.write_buf = busw ? nand_write_buf16 : nand_write_buf;
+	if (!chip->legacy.write_byte || chip->legacy.write_byte == nand_write_byte)
+		chip->legacy.write_byte = busw ? nand_write_byte16 : nand_write_byte;
+	if (!chip->legacy.read_buf || chip->legacy.read_buf == nand_read_buf)
+		chip->legacy.read_buf = busw ? nand_read_buf16 : nand_read_buf;
+}
+
+void nand_legacy_adjust_cmdfunc(struct nand_chip *chip)
+{
+	struct mtd_info *mtd = nand_to_mtd(chip);
+
+	/* Do not replace user supplied command function! */
+	if (mtd->writesize > 512 && chip->legacy.cmdfunc == nand_command)
+		chip->legacy.cmdfunc = nand_command_lp;
+}
+
+int nand_legacy_check_hooks(struct nand_chip *chip)
+{
+	/*
+	 * ->legacy.cmdfunc() is legacy and will only be used if ->exec_op() is
+	 * not populated.
+	 */
+	if (chip->exec_op)
+		return 0;
+
+	/*
+	 * Default functions assigned for ->legacy.cmdfunc() and
+	 * ->select_chip() both expect ->legacy.cmd_ctrl() to be populated.
+	 */
+	if ((!chip->legacy.cmdfunc || !chip->select_chip) &&
+	    !chip->legacy.cmd_ctrl) {
+		pr_err("->legacy.cmd_ctrl() should be provided\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}