Patchwork [3/8,v2] mtd: Add MPC5121 NAND Flash Controller driver

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Submitter Anatolij Gustschin
Date Jan. 27, 2010, 12:07 p.m.
Message ID <1264594052-20317-4-git-send-email-agust@denx.de>
Download mbox | patch
Permalink /patch/43788/
State New
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Comments

Anatolij Gustschin - Jan. 27, 2010, 12:07 p.m.
From: Piotr Ziecik <kosmo@semihalf.com>

Adds NAND Flash Controller driver for MPC5121 Revision 2.
All device features, except hardware ECC and power management,
are supported.

Signed-off-by: Piotr Ziecik <kosmo@semihalf.com>
Signed-off-by: Wolfgang Denk <wd@denx.de>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: <linux-mtd@lists.infradead.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: John Rigby <jcrigby@gmail.com>
---
Changes since v1:
 - add logfile with changes since previous version 

Changes since the patch version submitted in May 2009:

 - move mpc5121_nfc.h to the driver .c as there is only one user
 - remove DRV_VERSION macro
 - replace printk() by dev_*()
 - drop unnecessary .suspend and .resume initializations
 - remove duplicate .name/.owner settings
 - fix mpc5121_nfc_init() to "return of_register_platform_driver(&mpc5121_nfc_driver);"
 - move module_init() to just below the init function
 - remove MODULE_VERSION
 - use "mtd: Add MPC5121 NAND Flash Controller driver" as the subject,
   previously it was "mpc5121: Added NAND Flash Controller driver."

 arch/powerpc/platforms/512x/mpc512x_shared.c |    1 +
 drivers/mtd/nand/Kconfig                     |    7 +
 drivers/mtd/nand/Makefile                    |    1 +
 drivers/mtd/nand/mpc5121_nfc.c               |  916 ++++++++++++++++++++++++++
 4 files changed, 925 insertions(+), 0 deletions(-)
 create mode 100644 drivers/mtd/nand/mpc5121_nfc.c
Grant Likely - Jan. 27, 2010, 4:43 p.m.
On Wed, Jan 27, 2010 at 5:07 AM, Anatolij Gustschin <agust@denx.de> wrote:
> From: Piotr Ziecik <kosmo@semihalf.com>

Again, it is appropriate for you to claim patch ownership now as long
as you preserve the signed-off-by history.

>
> Adds NAND Flash Controller driver for MPC5121 Revision 2.
> All device features, except hardware ECC and power management,
> are supported.

A few comments below.

> diff --git a/arch/powerpc/platforms/512x/mpc512x_shared.c b/arch/powerpc/platforms/512x/mpc512x_shared.c
> index 4745028..6b8314c 100644
> --- a/arch/powerpc/platforms/512x/mpc512x_shared.c
> +++ b/arch/powerpc/platforms/512x/mpc512x_shared.c
> @@ -82,6 +82,7 @@ void __init mpc512x_init_IRQ(void)
>  static struct of_device_id __initdata of_bus_ids[] = {
>        { .compatible = "fsl,mpc5121-immr", },
>        { .compatible = "fsl,mpc5121-localbus", },
> +       { .compatible = "fsl,mpc5121-nfc", },
>        {},
>  };

This hunk shouldn't be in this patch since it touches arch code.  Keep
the NAND and arch bits in separate patches.

Also, this is probably not what you really want.  Doing it this way
means that each of the child nodes also get registered as of_platform
devices.  You want the platform code to only register the nfc@40000000
node.

> +static int __init mpc5121_nfc_probe(struct of_device *op,
> +                                       const struct of_device_id *match)

__devinit

> +{
> +       struct device_node *rootnode, *dn = op->node;
> +       struct device *dev = &op->dev;
> +       struct mpc5121_nfc_prv *prv;
> +       struct resource res;
> +       struct mtd_info *mtd;
> +#ifdef CONFIG_MTD_PARTITIONS
> +       struct mtd_partition *parts;
> +#endif
> +       struct nand_chip *chip;
> +       unsigned long regs_paddr, regs_size;
> +       const uint *chips_no;
> +       int resettime = 0;
> +       int retval = 0;
> +       int rev, len;
> +
> +       /*
> +        * Check SoC revision. This driver supports only NFC
> +        * in MPC5121 revision 2.
> +        */
> +       rev = (mfspr(SPRN_SVR) >> 4) & 0xF;
> +       if (rev != 2) {
> +               dev_err(dev, "SoC revision %u is not supported!\n", rev);
> +               return -ENXIO;
> +       }

*Only* revision 2?  Are future revisions of silicon assumed to be broken then?

> +static int __exit mpc5121_nfc_remove(struct of_device *op)

__devexit

> +static struct of_device_id mpc5121_nfc_match[] = {

...match[] __devinitdata = {

> +       { .compatible = "fsl,mpc5121-nfc", },
> +       {},
> +};
> +
> +static struct of_platform_driver mpc5121_nfc_driver = {
> +       .match_table    = mpc5121_nfc_match,
> +       .probe          = mpc5121_nfc_probe,
> +       .remove         = __exit_p(mpc5121_nfc_remove),

__devexit_p()

g.
Wolfgang Denk - Jan. 27, 2010, 8:24 p.m.
Dear Grant Likely,

In message <fa686aa41001270843u3b4e9687k699ad579de4460d4@mail.gmail.com> you wrote:
>
> > +       if (rev != 2) {
> > +               dev_err(dev, "SoC revision %u is not supported!\n", rev);
> > +               return -ENXIO;
> > +       }
>
> *Only* revision 2?  Are future revisions of silicon assumed to be broken then?

I vote for keeping it this way - if you look at the diffferences
between revision 1 and 2, or at differences between MPC5121/3 and
MPC5125, it is more than likely that revision 3, should it ever come
out, will be incompatible and require driver changes.

Best regards,

Wolfgang Denk

Patch

diff --git a/arch/powerpc/platforms/512x/mpc512x_shared.c b/arch/powerpc/platforms/512x/mpc512x_shared.c
index 4745028..6b8314c 100644
--- a/arch/powerpc/platforms/512x/mpc512x_shared.c
+++ b/arch/powerpc/platforms/512x/mpc512x_shared.c
@@ -82,6 +82,7 @@  void __init mpc512x_init_IRQ(void)
 static struct of_device_id __initdata of_bus_ids[] = {
 	{ .compatible = "fsl,mpc5121-immr", },
 	{ .compatible = "fsl,mpc5121-localbus", },
+	{ .compatible = "fsl,mpc5121-nfc", },
 	{},
 };
 
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 677cd53..099f002 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -442,6 +442,13 @@  config MTD_NAND_FSL_UPM
 	  Enables support for NAND Flash chips wired onto Freescale PowerPC
 	  processor localbus with User-Programmable Machine support.
 
+config MTD_NAND_MPC5121_NFC
+	tristate "MPC5121 built-in NAND Flash Controller support"
+	depends on PPC_MPC512x
+	help
+	  This enables the driver for the NAND flash controller on the
+	  MPC5121 SoC.
+
 config MTD_NAND_MXC
 	tristate "MXC NAND support"
 	depends on ARCH_MX2 || ARCH_MX3
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index 1407bd1..d4ddf05 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -42,5 +42,6 @@  obj-$(CONFIG_MTD_NAND_TXX9NDFMC)	+= txx9ndfmc.o
 obj-$(CONFIG_MTD_NAND_W90P910)		+= w90p910_nand.o
 obj-$(CONFIG_MTD_NAND_NOMADIK)		+= nomadik_nand.o
 obj-$(CONFIG_MTD_NAND_BCM_UMI)		+= bcm_umi_nand.o nand_bcm_umi.o
+obj-$(CONFIG_MTD_NAND_MPC5121_NFC)	+= mpc5121_nfc.o
 
 nand-objs := nand_base.o nand_bbt.o
diff --git a/drivers/mtd/nand/mpc5121_nfc.c b/drivers/mtd/nand/mpc5121_nfc.c
new file mode 100644
index 0000000..2980eb1
--- /dev/null
+++ b/drivers/mtd/nand/mpc5121_nfc.c
@@ -0,0 +1,916 @@ 
+/*
+ * Copyright 2004-2008 Freescale Semiconductor, Inc.
+ * Copyright 2009 Semihalf.
+ *
+ * Approved as OSADL project by a majority of OSADL members and funded
+ * by OSADL membership fees in 2009;  for details see www.osadl.org.
+ *
+ * Based on original driver from Freescale Semiconductor
+ * written by John Rigby <jrigby@freescale.com> on basis
+ * of drivers/mtd/nand/mxc_nand.c. Reworked and extended
+ * Piotr Ziecik <kosmo@semihalf.com>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/partitions.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+
+#include <asm/mpc5xxx.h>
+
+/* Addresses for NFC MAIN RAM BUFFER areas */
+#define NFC_MAIN_AREA(n)	((n) *  0x200)
+
+/* Addresses for NFC SPARE BUFFER areas */
+#define NFC_SPARE_BUFFERS	8
+#define NFC_SPARE_LEN		0x40
+#define NFC_SPARE_AREA(n)	(0x1000 + ((n) * NFC_SPARE_LEN))
+
+/* MPC5121 NFC registers */
+#define NFC_BUF_ADDR		0x1E04
+#define NFC_FLASH_ADDR		0x1E06
+#define NFC_FLASH_CMD		0x1E08
+#define NFC_CONFIG		0x1E0A
+#define NFC_ECC_STATUS1		0x1E0C
+#define NFC_ECC_STATUS2		0x1E0E
+#define NFC_SPAS		0x1E10
+#define NFC_WRPROT		0x1E12
+#define NFC_NF_WRPRST		0x1E18
+#define NFC_CONFIG1		0x1E1A
+#define NFC_CONFIG2		0x1E1C
+#define NFC_UNLOCKSTART_BLK0	0x1E20
+#define NFC_UNLOCKEND_BLK0	0x1E22
+#define NFC_UNLOCKSTART_BLK1	0x1E24
+#define NFC_UNLOCKEND_BLK1	0x1E26
+#define NFC_UNLOCKSTART_BLK2	0x1E28
+#define NFC_UNLOCKEND_BLK2	0x1E2A
+#define NFC_UNLOCKSTART_BLK3	0x1E2C
+#define NFC_UNLOCKEND_BLK3	0x1E2E
+
+/* Bit Definitions: NFC_BUF_ADDR */
+#define NFC_RBA_MASK		(7 << 0)
+#define NFC_ACTIVE_CS_SHIFT	5
+#define NFC_ACTIVE_CS_MASK	(3 << NFC_ACTIVE_CS_SHIFT)
+
+/* Bit Definitions: NFC_CONFIG */
+#define NFC_BLS_UNLOCKED	(1 << 1)
+
+/* Bit Definitions: NFC_CONFIG1 */
+#define NFC_ECC_4BIT		(1 << 0)
+#define NFC_FULL_PAGE_DMA	(1 << 1)
+#define NFC_SPARE_ONLY		(1 << 2)
+#define NFC_ECC_ENABLE		(1 << 3)
+#define NFC_INT_MASK		(1 << 4)
+#define NFC_BIG_ENDIAN		(1 << 5)
+#define NFC_RESET		(1 << 6)
+#define NFC_CE			(1 << 7)
+#define NFC_ONE_CYCLE		(1 << 8)
+#define NFC_PPB_32		(0 << 9)
+#define NFC_PPB_64		(1 << 9)
+#define NFC_PPB_128		(2 << 9)
+#define NFC_PPB_256		(3 << 9)
+#define NFC_PPB_MASK		(3 << 9)
+#define NFC_FULL_PAGE_INT	(1 << 11)
+
+/* Bit Definitions: NFC_CONFIG2 */
+#define NFC_COMMAND		(1 << 0)
+#define NFC_ADDRESS		(1 << 1)
+#define NFC_INPUT		(1 << 2)
+#define NFC_OUTPUT		(1 << 3)
+#define NFC_ID			(1 << 4)
+#define NFC_STATUS		(1 << 5)
+#define NFC_CMD_FAIL		(1 << 15)
+#define NFC_INT			(1 << 15)
+
+/* Bit Definitions: NFC_WRPROT */
+#define NFC_WPC_LOCK_TIGHT	(1 << 0)
+#define NFC_WPC_LOCK		(1 << 1)
+#define NFC_WPC_UNLOCK		(1 << 2)
+
+#define	DRV_NAME		"mpc5121_nfc"
+
+/* Timeouts */
+#define NFC_RESET_TIMEOUT	1000		/* 1 ms */
+#define NFC_TIMEOUT		(HZ / 10)	/* 1/10 s */
+
+struct mpc5121_nfc_prv {
+	struct mtd_info		mtd;
+	struct nand_chip	chip;
+	int			irq;
+	void __iomem		*regs;
+	struct clk		*clk;
+	wait_queue_head_t	irq_waitq;
+	uint			column;
+	int			spareonly;
+	void __iomem		*csreg;
+	struct device		*dev;
+};
+
+static void mpc5121_nfc_done(struct mtd_info *mtd);
+
+#ifdef CONFIG_MTD_PARTITIONS
+static const char *mpc5121_nfc_pprobes[] = { "cmdlinepart", NULL };
+#endif
+
+/* Read NFC register */
+static inline u16 nfc_read(struct mtd_info *mtd, uint reg)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+
+	return in_be16(prv->regs + reg);
+}
+
+/* Write NFC register */
+static inline void nfc_write(struct mtd_info *mtd, uint reg, u16 val)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+
+	out_be16(prv->regs + reg, val);
+}
+
+/* Set bits in NFC register */
+static inline void nfc_set(struct mtd_info *mtd, uint reg, u16 bits)
+{
+	nfc_write(mtd, reg, nfc_read(mtd, reg) | bits);
+}
+
+/* Clear bits in NFC register */
+static inline void nfc_clear(struct mtd_info *mtd, uint reg, u16 bits)
+{
+	nfc_write(mtd, reg, nfc_read(mtd, reg) & ~bits);
+}
+
+/* Invoke address cycle */
+static inline void mpc5121_nfc_send_addr(struct mtd_info *mtd, u16 addr)
+{
+	nfc_write(mtd, NFC_FLASH_ADDR, addr);
+	nfc_write(mtd, NFC_CONFIG2, NFC_ADDRESS);
+	mpc5121_nfc_done(mtd);
+}
+
+/* Invoke command cycle */
+static inline void mpc5121_nfc_send_cmd(struct mtd_info *mtd, u16 cmd)
+{
+	nfc_write(mtd, NFC_FLASH_CMD, cmd);
+	nfc_write(mtd, NFC_CONFIG2, NFC_COMMAND);
+	mpc5121_nfc_done(mtd);
+}
+
+/* Send data from NFC buffers to NAND flash */
+static inline void mpc5121_nfc_send_prog_page(struct mtd_info *mtd)
+{
+	nfc_clear(mtd, NFC_BUF_ADDR, NFC_RBA_MASK);
+	nfc_write(mtd, NFC_CONFIG2, NFC_INPUT);
+	mpc5121_nfc_done(mtd);
+}
+
+/* Receive data from NAND flash */
+static inline void mpc5121_nfc_send_read_page(struct mtd_info *mtd)
+{
+	nfc_clear(mtd, NFC_BUF_ADDR, NFC_RBA_MASK);
+	nfc_write(mtd, NFC_CONFIG2, NFC_OUTPUT);
+	mpc5121_nfc_done(mtd);
+}
+
+/* Receive ID from NAND flash */
+static inline void mpc5121_nfc_send_read_id(struct mtd_info *mtd)
+{
+	nfc_clear(mtd, NFC_BUF_ADDR, NFC_RBA_MASK);
+	nfc_write(mtd, NFC_CONFIG2, NFC_ID);
+	mpc5121_nfc_done(mtd);
+}
+
+/* Receive status from NAND flash */
+static inline void mpc5121_nfc_send_read_status(struct mtd_info *mtd)
+{
+	nfc_clear(mtd, NFC_BUF_ADDR, NFC_RBA_MASK);
+	nfc_write(mtd, NFC_CONFIG2, NFC_STATUS);
+	mpc5121_nfc_done(mtd);
+}
+
+/* NFC interrupt handler */
+static irqreturn_t mpc5121_nfc_irq(int irq, void *data)
+{
+	struct mtd_info *mtd = data;
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+
+	nfc_set(mtd, NFC_CONFIG1, NFC_INT_MASK);
+	wake_up(&prv->irq_waitq);
+
+	return IRQ_HANDLED;
+}
+
+/* Wait for operation complete */
+static void mpc5121_nfc_done(struct mtd_info *mtd)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+	int rv;
+
+	if ((nfc_read(mtd, NFC_CONFIG2) & NFC_INT) == 0) {
+		nfc_clear(mtd, NFC_CONFIG1, NFC_INT_MASK);
+		rv = wait_event_timeout(prv->irq_waitq,
+			(nfc_read(mtd, NFC_CONFIG2) & NFC_INT), NFC_TIMEOUT);
+
+		if (!rv)
+			dev_warn(prv->dev,
+				"Timeout while waiting for interrupt.\n");
+	}
+
+	nfc_clear(mtd, NFC_CONFIG2, NFC_INT);
+}
+
+/* Do address cycle(s) */
+static void mpc5121_nfc_addr_cycle(struct mtd_info *mtd, int column, int page)
+{
+	struct nand_chip *chip = mtd->priv;
+	u32 pagemask = chip->pagemask;
+
+	if (column != -1) {
+		mpc5121_nfc_send_addr(mtd, column);
+		if (mtd->writesize > 512)
+			mpc5121_nfc_send_addr(mtd, column >> 8);
+	}
+
+	if (page != -1) {
+		do {
+			mpc5121_nfc_send_addr(mtd, page & 0xFF);
+			page >>= 8;
+			pagemask >>= 8;
+		} while (pagemask);
+	}
+}
+
+/* Control chip select signals */
+static void mpc5121_nfc_select_chip(struct mtd_info *mtd, int chip)
+{
+	if (chip < 0) {
+		nfc_clear(mtd, NFC_CONFIG1, NFC_CE);
+		return;
+	}
+
+	nfc_clear(mtd, NFC_BUF_ADDR, NFC_ACTIVE_CS_MASK);
+	nfc_set(mtd, NFC_BUF_ADDR, (chip << NFC_ACTIVE_CS_SHIFT) &
+							NFC_ACTIVE_CS_MASK);
+	nfc_set(mtd, NFC_CONFIG1, NFC_CE);
+}
+
+/* Init external chip select logic on ADS5121 board */
+static int ads5121_chipselect_init(struct mtd_info *mtd)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+	struct device_node *dn;
+
+	dn = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld");
+	if (dn) {
+		prv->csreg = of_iomap(dn, 0);
+		of_node_put(dn);
+		if (!prv->csreg)
+			return -ENOMEM;
+
+		/* CPLD Register 9 controls NAND /CE Lines */
+		prv->csreg += 9;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+/* Control chips select signal on ADS5121 board */
+static void ads5121_select_chip(struct mtd_info *mtd, int chip)
+{
+	struct nand_chip *nand = mtd->priv;
+	struct mpc5121_nfc_prv *prv = nand->priv;
+	u8 v;
+
+	v = in_8(prv->csreg);
+	v |= 0x0F;
+
+	if (chip >= 0) {
+		mpc5121_nfc_select_chip(mtd, 0);
+		v &= ~(1 << chip);
+	} else
+		mpc5121_nfc_select_chip(mtd, -1);
+
+	out_8(prv->csreg, v);
+}
+
+/* Read NAND Ready/Busy signal */
+static int mpc5121_nfc_dev_ready(struct mtd_info *mtd)
+{
+	/*
+	 * NFC handles ready/busy signal internally. Therefore, this function
+	 * always returns status as ready.
+	 */
+	return 1;
+}
+
+/* Write command to NAND flash */
+static void mpc5121_nfc_command(struct mtd_info *mtd, unsigned command,
+							int column, int page)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+
+	prv->column = (column >= 0) ? column : 0;
+	prv->spareonly = 0;
+
+	switch (command) {
+	case NAND_CMD_PAGEPROG:
+		mpc5121_nfc_send_prog_page(mtd);
+		break;
+	/*
+	 * NFC does not support sub-page reads and writes,
+	 * so emulate them using full page transfers.
+	 */
+	case NAND_CMD_READ0:
+		column = 0;
+		break;
+
+	case NAND_CMD_READ1:
+		prv->column += 256;
+		command = NAND_CMD_READ0;
+		column = 0;
+		break;
+
+	case NAND_CMD_READOOB:
+		prv->spareonly = 1;
+		command = NAND_CMD_READ0;
+		column = 0;
+		break;
+
+	case NAND_CMD_SEQIN:
+		mpc5121_nfc_command(mtd, NAND_CMD_READ0, column, page);
+		column = 0;
+		break;
+
+	case NAND_CMD_ERASE1:
+	case NAND_CMD_ERASE2:
+	case NAND_CMD_READID:
+	case NAND_CMD_STATUS:
+		break;
+
+	default:
+		return;
+	}
+
+	mpc5121_nfc_send_cmd(mtd, command);
+	mpc5121_nfc_addr_cycle(mtd, column, page);
+
+	switch (command) {
+	case NAND_CMD_READ0:
+		if (mtd->writesize > 512)
+			mpc5121_nfc_send_cmd(mtd, NAND_CMD_READSTART);
+		mpc5121_nfc_send_read_page(mtd);
+		break;
+
+	case NAND_CMD_READID:
+		mpc5121_nfc_send_read_id(mtd);
+		break;
+
+	case NAND_CMD_STATUS:
+		mpc5121_nfc_send_read_status(mtd);
+		if (chip->options & NAND_BUSWIDTH_16)
+			prv->column = 1;
+		else
+			prv->column = 0;
+		break;
+	}
+}
+
+/* Copy data from/to NFC spare buffers. */
+static void mpc5121_nfc_copy_spare(struct mtd_info *mtd, uint offset,
+						u8 *buffer, uint size, int wr)
+{
+	struct nand_chip *nand = mtd->priv;
+	struct mpc5121_nfc_prv *prv = nand->priv;
+	uint o, s, sbsize, blksize;
+
+	/*
+	 * NAND spare area is available through NFC spare buffers.
+	 * The NFC divides spare area into (page_size / 512) chunks.
+	 * Each chunk is placed into separate spare memory area, using
+	 * first (spare_size / num_of_chunks) bytes of the buffer.
+	 *
+	 * For NAND device in which the spare area is not divided fully
+	 * by the number of chunks, number of used bytes in each spare
+	 * buffer is rounded down to the nearest even number of bytes,
+	 * and all remaining bytes are added to the last used spare area.
+	 *
+	 * For more information read section 26.6.10 of MPC5121e
+	 * Microcontroller Reference Manual, Rev. 3.
+	 */
+
+	/* Calculate number of valid bytes in each spare buffer */
+	sbsize = (mtd->oobsize / (mtd->writesize / 512)) & ~1;
+
+	while (size) {
+		/* Calculate spare buffer number */
+		s = offset / sbsize;
+		if (s > NFC_SPARE_BUFFERS - 1)
+			s = NFC_SPARE_BUFFERS - 1;
+
+		/*
+		 * Calculate offset to requested data block in selected spare
+		 * buffer and its size.
+		 */
+		o = offset - (s * sbsize);
+		blksize = min(sbsize - o, size);
+
+		if (wr)
+			memcpy_toio(prv->regs + NFC_SPARE_AREA(s) + o,
+							buffer, blksize);
+		else
+			memcpy_fromio(buffer,
+				prv->regs + NFC_SPARE_AREA(s) + o, blksize);
+
+		buffer += blksize;
+		offset += blksize;
+		size -= blksize;
+	};
+}
+
+/* Copy data from/to NFC main and spare buffers */
+static void mpc5121_nfc_buf_copy(struct mtd_info *mtd, u_char *buf, int len,
+									int wr)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+	uint c = prv->column;
+	uint l;
+
+	/* Handle spare area access */
+	if (prv->spareonly || c >= mtd->writesize) {
+		/* Calculate offset from beginning of spare area */
+		if (c >= mtd->writesize)
+			c -= mtd->writesize;
+
+		prv->column += len;
+		mpc5121_nfc_copy_spare(mtd, c, buf, len, wr);
+		return;
+	}
+
+	/*
+	 * Handle main area access - limit copy length to prevent
+	 * crossing main/spare boundary.
+	 */
+	l = min((uint)len, mtd->writesize - c);
+	prv->column += l;
+
+	if (wr)
+		memcpy_toio(prv->regs + NFC_MAIN_AREA(0) + c, buf, l);
+	else
+		memcpy_fromio(buf, prv->regs + NFC_MAIN_AREA(0) + c, l);
+
+	/* Handle crossing main/spare boundary */
+	if (l != len) {
+		buf += l;
+		len -= l;
+		mpc5121_nfc_buf_copy(mtd, buf, len, wr);
+	}
+}
+
+/* Read data from NFC buffers */
+static void mpc5121_nfc_read_buf(struct mtd_info *mtd, u_char *buf, int len)
+{
+	mpc5121_nfc_buf_copy(mtd, buf, len, 0);
+}
+
+/* Write data to NFC buffers */
+static void mpc5121_nfc_write_buf(struct mtd_info *mtd,
+						const u_char *buf, int len)
+{
+	mpc5121_nfc_buf_copy(mtd, (u_char *)buf, len, 1);
+}
+
+/* Compare buffer with NAND flash */
+static int mpc5121_nfc_verify_buf(struct mtd_info *mtd,
+						const u_char *buf, int len)
+{
+	u_char tmp[256];
+	uint bsize;
+
+	while (len) {
+		bsize = min(len, 256);
+		mpc5121_nfc_read_buf(mtd, tmp, bsize);
+
+		if (memcmp(buf, tmp, bsize))
+			return 1;
+
+		buf += bsize;
+		len -= bsize;
+	}
+
+	return 0;
+}
+
+/* Read byte from NFC buffers */
+static u8 mpc5121_nfc_read_byte(struct mtd_info *mtd)
+{
+	u8 tmp;
+
+	mpc5121_nfc_read_buf(mtd, &tmp, sizeof(tmp));
+
+	return tmp;
+}
+
+/* Read word from NFC buffers */
+static u16 mpc5121_nfc_read_word(struct mtd_info *mtd)
+{
+	u16 tmp;
+
+	mpc5121_nfc_read_buf(mtd, (u_char *)&tmp, sizeof(tmp));
+
+	return tmp;
+}
+
+/*
+ * Read NFC configuration from Reset Config Word
+ *
+ * NFC is configured during reset in basis of information stored
+ * in Reset Config Word. There is no other way to set NAND block
+ * size, spare size and bus width.
+ */
+static int mpc5121_nfc_read_hw_config(struct mtd_info *mtd)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+	struct mpc512x_reset_module *rm;
+	struct device_node *rmnode;
+	uint rcw_pagesize = 0;
+	uint rcw_sparesize = 0;
+	uint rcw_width;
+	uint rcwh;
+	uint romloc, ps;
+
+	rmnode = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-reset");
+	if (!rmnode) {
+		dev_err(prv->dev, "Missing 'fsl,mpc5121-reset' "
+					"node in device tree!\n");
+		return -ENODEV;
+	}
+
+	rm = of_iomap(rmnode, 0);
+	if (!rm) {
+		dev_err(prv->dev, "Error mapping reset module node!\n");
+		return -EBUSY;
+	}
+
+	rcwh = in_be32(&rm->rcwhr);
+
+	/* Bit 6: NFC bus width */
+	rcw_width = ((rcwh >> 6) & 0x1) ? 2 : 1;
+
+	/* Bit 7: NFC Page/Spare size */
+	ps = (rcwh >> 7) & 0x1;
+
+	/* Bits [22:21]: ROM Location */
+	romloc = (rcwh >> 21) & 0x3;
+
+	/* Decode RCW bits */
+	switch ((ps << 2) | romloc) {
+	case 0x00:
+	case 0x01:
+		rcw_pagesize = 512;
+		rcw_sparesize = 16;
+		break;
+	case 0x02:
+	case 0x03:
+		rcw_pagesize = 4096;
+		rcw_sparesize = 128;
+		break;
+	case 0x04:
+	case 0x05:
+		rcw_pagesize = 2048;
+		rcw_sparesize = 64;
+		break;
+	case 0x06:
+	case 0x07:
+		rcw_pagesize = 4096;
+		rcw_sparesize = 218;
+		break;
+	}
+
+	mtd->writesize = rcw_pagesize;
+	mtd->oobsize = rcw_sparesize;
+	if (rcw_width == 2)
+		chip->options |= NAND_BUSWIDTH_16;
+
+	dev_notice(prv->dev, "Configured for "
+				"%u-bit NAND, page size %u "
+				"with %u spare.\n",
+				rcw_width * 8, rcw_pagesize,
+				rcw_sparesize);
+	iounmap(rm);
+	of_node_put(rmnode);
+	return 0;
+}
+
+/* Free driver resources */
+static void mpc5121_nfc_free(struct device *dev, struct mtd_info *mtd)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+
+	if (prv->clk) {
+		clk_disable(prv->clk);
+		clk_put(prv->clk);
+	}
+
+	if (prv->csreg)
+		iounmap(prv->csreg);
+}
+
+static int __init mpc5121_nfc_probe(struct of_device *op,
+					const struct of_device_id *match)
+{
+	struct device_node *rootnode, *dn = op->node;
+	struct device *dev = &op->dev;
+	struct mpc5121_nfc_prv *prv;
+	struct resource res;
+	struct mtd_info *mtd;
+#ifdef CONFIG_MTD_PARTITIONS
+	struct mtd_partition *parts;
+#endif
+	struct nand_chip *chip;
+	unsigned long regs_paddr, regs_size;
+	const uint *chips_no;
+	int resettime = 0;
+	int retval = 0;
+	int rev, len;
+
+	/*
+	 * Check SoC revision. This driver supports only NFC
+	 * in MPC5121 revision 2.
+	 */
+	rev = (mfspr(SPRN_SVR) >> 4) & 0xF;
+	if (rev != 2) {
+		dev_err(dev, "SoC revision %u is not supported!\n", rev);
+		return -ENXIO;
+	}
+
+	prv = devm_kzalloc(dev, sizeof(*prv), GFP_KERNEL);
+	if (!prv) {
+		dev_err(dev, "Memory exhausted!\n");
+		return -ENOMEM;
+	}
+
+	mtd = &prv->mtd;
+	chip = &prv->chip;
+
+	mtd->priv = chip;
+	chip->priv = prv;
+	prv->dev = dev;
+
+	/* Read NFC configuration from Reset Config Word */
+	retval = mpc5121_nfc_read_hw_config(mtd);
+	if (retval) {
+		dev_err(dev, "Unable to read NFC config!\n");
+		return retval;
+	}
+
+	prv->irq = irq_of_parse_and_map(dn, 0);
+	if (prv->irq == NO_IRQ) {
+		dev_err(dev, "Error mapping IRQ!\n");
+		return -EINVAL;
+	}
+
+	retval = of_address_to_resource(dn, 0, &res);
+	if (retval) {
+		dev_err(dev, "Error parsing memory region!\n");
+		return retval;
+	}
+
+	chips_no = of_get_property(dn, "chips", &len);
+	if (!chips_no || len != sizeof(*chips_no)) {
+		dev_err(dev, "Invalid/missing 'chips' property!\n");
+		return -EINVAL;
+	}
+
+	regs_paddr = res.start;
+	regs_size = res.end - res.start + 1;
+
+	if (!devm_request_mem_region(dev, regs_paddr, regs_size, DRV_NAME)) {
+		dev_err(dev, "Error requesting memory region!\n");
+		return -EBUSY;
+	}
+
+	prv->regs = devm_ioremap(dev, regs_paddr, regs_size);
+	if (!prv->regs) {
+		dev_err(dev, "Error mapping memory region!\n");
+		return -ENOMEM;
+	}
+
+	mtd->name = "MPC5121 NAND";
+	chip->dev_ready = mpc5121_nfc_dev_ready;
+	chip->cmdfunc = mpc5121_nfc_command;
+	chip->read_byte = mpc5121_nfc_read_byte;
+	chip->read_word = mpc5121_nfc_read_word;
+	chip->read_buf = mpc5121_nfc_read_buf;
+	chip->write_buf = mpc5121_nfc_write_buf;
+	chip->verify_buf = mpc5121_nfc_verify_buf;
+	chip->select_chip = mpc5121_nfc_select_chip;
+	chip->options = NAND_NO_AUTOINCR | NAND_USE_FLASH_BBT;
+	chip->ecc.mode = NAND_ECC_SOFT;
+
+	/* Support external chip-select logic on ADS5121 board */
+	rootnode = of_find_node_by_path("/");
+	if (of_device_is_compatible(rootnode, "fsl,mpc5121ads")) {
+		retval = ads5121_chipselect_init(mtd);
+		if (retval) {
+			dev_err(dev, "Chipselect init error!\n");
+			of_node_put(rootnode);
+			return retval;
+		}
+
+		chip->select_chip = ads5121_select_chip;
+	}
+	of_node_put(rootnode);
+
+	/* Enable NFC clock */
+	prv->clk = clk_get(dev, "nfc_clk");
+	if (!prv->clk) {
+		dev_err(dev, "Unable to acquire NFC clock!\n");
+		retval = -ENODEV;
+		goto error;
+	}
+
+	clk_enable(prv->clk);
+
+	/* Reset NAND Flash controller */
+	nfc_set(mtd, NFC_CONFIG1, NFC_RESET);
+	while (nfc_read(mtd, NFC_CONFIG1) & NFC_RESET) {
+		if (resettime++ >= NFC_RESET_TIMEOUT) {
+			dev_err(dev, "Timeout while resetting NFC!\n");
+			retval = -EINVAL;
+			goto error;
+		}
+
+		udelay(1);
+	}
+
+	/* Enable write to NFC memory */
+	nfc_write(mtd, NFC_CONFIG, NFC_BLS_UNLOCKED);
+
+	/* Enable write to all NAND pages */
+	nfc_write(mtd, NFC_UNLOCKSTART_BLK0, 0x0000);
+	nfc_write(mtd, NFC_UNLOCKEND_BLK0, 0xFFFF);
+	nfc_write(mtd, NFC_WRPROT, NFC_WPC_UNLOCK);
+
+	/*
+	 * Setup NFC:
+	 *	- Big Endian transfers,
+	 *	- Interrupt after full page read/write.
+	 */
+	nfc_write(mtd, NFC_CONFIG1, NFC_BIG_ENDIAN | NFC_INT_MASK |
+							NFC_FULL_PAGE_INT);
+
+	/* Set spare area size */
+	nfc_write(mtd, NFC_SPAS, mtd->oobsize >> 1);
+
+	init_waitqueue_head(&prv->irq_waitq);
+	retval = devm_request_irq(dev, prv->irq, &mpc5121_nfc_irq, 0, DRV_NAME,
+									mtd);
+	if (retval) {
+		dev_err(dev, "Error requesting IRQ!\n");
+		goto error;
+	}
+
+	/* Detect NAND chips */
+	if (nand_scan(mtd, *chips_no)) {
+		dev_err(dev, "NAND Flash not found !\n");
+		devm_free_irq(dev, prv->irq, mtd);
+		retval = -ENXIO;
+		goto error;
+	}
+
+	/* Set erase block size */
+	switch (mtd->erasesize / mtd->writesize) {
+	case 32:
+		nfc_set(mtd, NFC_CONFIG1, NFC_PPB_32);
+		break;
+
+	case 64:
+		nfc_set(mtd, NFC_CONFIG1, NFC_PPB_64);
+		break;
+
+	case 128:
+		nfc_set(mtd, NFC_CONFIG1, NFC_PPB_128);
+		break;
+
+	case 256:
+		nfc_set(mtd, NFC_CONFIG1, NFC_PPB_256);
+		break;
+
+	default:
+		dev_err(dev, "Unsupported NAND flash!\n");
+		devm_free_irq(dev, prv->irq, mtd);
+		retval = -ENXIO;
+		goto error;
+	}
+
+	dev_set_drvdata(dev, mtd);
+
+	/* Register device in MTD */
+#ifdef CONFIG_MTD_PARTITIONS
+	retval = parse_mtd_partitions(mtd, mpc5121_nfc_pprobes, &parts, 0);
+#ifdef CONFIG_MTD_OF_PARTS
+	if (retval == 0)
+		retval = of_mtd_parse_partitions(dev, dn, &parts);
+#endif
+	if (retval < 0) {
+		dev_err(dev, "Error parsing MTD partitions!\n");
+		devm_free_irq(dev, prv->irq, mtd);
+		retval = -EINVAL;
+		goto error;
+	}
+
+	if (retval > 0)
+		retval = add_mtd_partitions(mtd, parts, retval);
+	else
+#endif
+		retval = add_mtd_device(mtd);
+
+	if (retval) {
+		dev_err(dev, "Error adding MTD device!\n");
+		devm_free_irq(dev, prv->irq, mtd);
+		goto error;
+	}
+
+	return 0;
+error:
+	mpc5121_nfc_free(dev, mtd);
+	return retval;
+}
+
+static int __exit mpc5121_nfc_remove(struct of_device *op)
+{
+	struct device *dev = &op->dev;
+	struct mtd_info *mtd = dev_get_drvdata(dev);
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+
+	nand_release(mtd);
+	devm_free_irq(dev, prv->irq, mtd);
+	mpc5121_nfc_free(dev, mtd);
+
+	return 0;
+}
+
+static struct of_device_id mpc5121_nfc_match[] = {
+	{ .compatible = "fsl,mpc5121-nfc", },
+	{},
+};
+
+static struct of_platform_driver mpc5121_nfc_driver = {
+	.match_table	= mpc5121_nfc_match,
+	.probe		= mpc5121_nfc_probe,
+	.remove		= __exit_p(mpc5121_nfc_remove),
+	.driver		= {
+		.name	= DRV_NAME,
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init mpc5121_nfc_init(void)
+{
+	return of_register_platform_driver(&mpc5121_nfc_driver);
+}
+
+module_init(mpc5121_nfc_init);
+
+static void __exit mpc5121_nfc_cleanup(void)
+{
+	of_unregister_platform_driver(&mpc5121_nfc_driver);
+}
+
+module_exit(mpc5121_nfc_cleanup);
+
+MODULE_AUTHOR("Freescale Semiconductor, Inc.");
+MODULE_DESCRIPTION("MPC5121 NAND MTD driver");
+MODULE_LICENSE("GPL");