mtd: nand: Add+use mtd_to/from_nand and nand_get/set_controller_data

These functions are part of the Linux 4.6 sync.  They are being added
before the main sync patch in order to make it easier to address the
issue across all NAND drivers (many/most of which do not closely track
their Linux counterparts) separately from other merge issues.

Signed-off-by: Scott Wood <oss@buserror.net>
diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
index 5e7b9cf..f935055 100644
--- a/drivers/mtd/nand/mxc_nand.c
+++ b/drivers/mtd/nand/mxc_nand.c
@@ -351,8 +351,8 @@
 
 static void _mxc_nand_enable_hwecc(struct mtd_info *mtd, int on)
 {
-	struct nand_chip *nand_chip = mtd->priv;
-	struct mxc_nand_host *host = nand_chip->priv;
+	struct nand_chip *nand_chip = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
 #if defined(MXC_NFC_V1) || defined(MXC_NFC_V2_1)
 	uint16_t tmp = readnfc(&host->regs->config1);
 
@@ -386,7 +386,7 @@
 				      struct nand_chip *chip,
 				      int page)
 {
-	struct mxc_nand_host *host = chip->priv;
+	struct mxc_nand_host *host = nand_get_controller_data(chip);
 	uint8_t *buf = chip->oob_poi;
 	int length = mtd->oobsize;
 	int eccpitch = chip->ecc.bytes + chip->ecc.prepad + chip->ecc.postpad;
@@ -441,7 +441,7 @@
 					   int oob_required,
 					   int page)
 {
-	struct mxc_nand_host *host = chip->priv;
+	struct mxc_nand_host *host = nand_get_controller_data(chip);
 	int eccsize = chip->ecc.size;
 	int eccbytes = chip->ecc.bytes;
 	int eccpitch = eccbytes + chip->ecc.prepad + chip->ecc.postpad;
@@ -486,7 +486,7 @@
 				       int oob_required,
 				       int page)
 {
-	struct mxc_nand_host *host = chip->priv;
+	struct mxc_nand_host *host = nand_get_controller_data(chip);
 	int n, eccsize = chip->ecc.size;
 	int eccbytes = chip->ecc.bytes;
 	int eccpitch = eccbytes + chip->ecc.prepad + chip->ecc.postpad;
@@ -550,7 +550,7 @@
 static int mxc_nand_write_oob_syndrome(struct mtd_info *mtd,
 				       struct nand_chip *chip, int page)
 {
-	struct mxc_nand_host *host = chip->priv;
+	struct mxc_nand_host *host = nand_get_controller_data(chip);
 	int eccpitch = chip->ecc.bytes + chip->ecc.prepad + chip->ecc.postpad;
 	int length = mtd->oobsize;
 	int i, len, status, steps = chip->ecc.steps;
@@ -578,7 +578,7 @@
 					     const uint8_t *buf,
 					     int oob_required)
 {
-	struct mxc_nand_host *host = chip->priv;
+	struct mxc_nand_host *host = nand_get_controller_data(chip);
 	int eccsize = chip->ecc.size;
 	int eccbytes = chip->ecc.bytes;
 	int eccpitch = eccbytes + chip->ecc.prepad + chip->ecc.postpad;
@@ -618,7 +618,7 @@
 					 const uint8_t *buf,
 					 int oob_required)
 {
-	struct mxc_nand_host *host = chip->priv;
+	struct mxc_nand_host *host = nand_get_controller_data(chip);
 	int i, n, eccsize = chip->ecc.size;
 	int eccbytes = chip->ecc.bytes;
 	int eccpitch = eccbytes + chip->ecc.prepad + chip->ecc.postpad;
@@ -661,8 +661,8 @@
 static int mxc_nand_correct_data(struct mtd_info *mtd, u_char *dat,
 				 u_char *read_ecc, u_char *calc_ecc)
 {
-	struct nand_chip *nand_chip = mtd->priv;
-	struct mxc_nand_host *host = nand_chip->priv;
+	struct nand_chip *nand_chip = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
 	uint32_t ecc_status = readl(&host->regs->ecc_status_result);
 	int subpages = mtd->writesize / nand_chip->subpagesize;
 	int pg2blk_shift = nand_chip->phys_erase_shift -
@@ -700,8 +700,8 @@
 static int mxc_nand_correct_data(struct mtd_info *mtd, u_char *dat,
 				 u_char *read_ecc, u_char *calc_ecc)
 {
-	struct nand_chip *nand_chip = mtd->priv;
-	struct mxc_nand_host *host = nand_chip->priv;
+	struct nand_chip *nand_chip = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
 
 	/*
 	 * 1-Bit errors are automatically corrected in HW.  No need for
@@ -729,8 +729,8 @@
 
 static u_char mxc_nand_read_byte(struct mtd_info *mtd)
 {
-	struct nand_chip *nand_chip = mtd->priv;
-	struct mxc_nand_host *host = nand_chip->priv;
+	struct nand_chip *nand_chip = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
 	uint8_t ret = 0;
 	uint16_t col;
 	uint16_t __iomem *main_buf =
@@ -769,8 +769,8 @@
 
 static uint16_t mxc_nand_read_word(struct mtd_info *mtd)
 {
-	struct nand_chip *nand_chip = mtd->priv;
-	struct mxc_nand_host *host = nand_chip->priv;
+	struct nand_chip *nand_chip = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
 	uint16_t col, ret;
 	uint16_t __iomem *p;
 
@@ -821,8 +821,8 @@
 static void mxc_nand_write_buf(struct mtd_info *mtd,
 				const u_char *buf, int len)
 {
-	struct nand_chip *nand_chip = mtd->priv;
-	struct mxc_nand_host *host = nand_chip->priv;
+	struct nand_chip *nand_chip = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
 	int n, col, i = 0;
 
 	MTDDEBUG(MTD_DEBUG_LEVEL3,
@@ -895,8 +895,8 @@
  */
 static void mxc_nand_read_buf(struct mtd_info *mtd, u_char *buf, int len)
 {
-	struct nand_chip *nand_chip = mtd->priv;
-	struct mxc_nand_host *host = nand_chip->priv;
+	struct nand_chip *nand_chip = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
 	int n, col, i = 0;
 
 	MTDDEBUG(MTD_DEBUG_LEVEL3,
@@ -955,8 +955,8 @@
  */
 static void mxc_nand_select_chip(struct mtd_info *mtd, int chip)
 {
-	struct nand_chip *nand_chip = mtd->priv;
-	struct mxc_nand_host *host = nand_chip->priv;
+	struct nand_chip *nand_chip = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
 
 	switch (chip) {
 	case -1:
@@ -982,8 +982,8 @@
 void mxc_nand_command(struct mtd_info *mtd, unsigned command,
 				int column, int page_addr)
 {
-	struct nand_chip *nand_chip = mtd->priv;
-	struct mxc_nand_host *host = nand_chip->priv;
+	struct nand_chip *nand_chip = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
 
 	MTDDEBUG(MTD_DEBUG_LEVEL3,
 	      "mxc_nand_command (cmd = 0x%x, col = 0x%x, page = 0x%x)\n",
@@ -1165,13 +1165,12 @@
 
 	/* structures must be linked */
 	mtd = &this->mtd;
-	mtd->priv = this;
 	host->nand = this;
 
 	/* 5 us command delay time */
 	this->chip_delay = 5;
 
-	this->priv = host;
+	nand_set_controller_data(this, host);
 	this->dev_ready = mxc_nand_dev_ready;
 	this->cmdfunc = mxc_nand_command;
 	this->select_chip = mxc_nand_select_chip;