diff mbox

[v8,1/5] mtd: nand: vf610_nfc: Freescale NFC for VF610, MPC5125 and others

Message ID 1438015365-15685-2-git-send-email-stefan@agner.ch (mailing list archive)
State New, archived
Headers show

Commit Message

Stefan Agner July 27, 2015, 4:42 p.m. UTC
This driver supports Freescale NFC (NAND flash controller) found on
Vybrid (VF610), MPC5125, MCF54418 and Kinetis K70. The driver has
been tested on 8-bit and 16-bit NAND interface and supports ONFI
parameter page reading.

Limitations:
- DMA and pipelining not used
- Pages larger than 2k are not supported
- No hardware ECC

The driver has only been tested on Vybrid SoC VF610 and VF500.

Some paths have been hand-optimized and evaluated by measurements
made using mtd_speedtest.ko on a 100MB MTD partition.

Colibri VF50
    eb write     %   eb read     %   page write      %   page read     %
rel/opt     5175           11537                4560             11039
opt         5164 -0.21     11420 -1.01          4737 +3.88       10918 -1.10
none        5113 -1.20     11352 -1.60          4490 -1.54       10865 -1.58

Colibri VF61
    eb write     %   eb read     %   page write      %   page read     %
rel/opt     5766           13096                5459             12846
opt         5883 +2.03     13064 -0.24          5561 +1.87       12802 -0.34
none        5701 -1.13     12980 -0.89          5488 +0.53       12735 -0.86

rel = using readl_relaxed/writel_relaxed in optimized paths
opt = hand-optimized by combining multiple accesses into one read/write

The measurements have not been statistically verfied, hence use them
with care. The author came to the conclusion that using the relaxed
variants of readl/writel are not worth the additional code.

Signed-off-by: Bill Pringlemeir <bpringlemeir@nbsps.com>
Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 MAINTAINERS                  |   6 +
 drivers/mtd/nand/Kconfig     |   9 +
 drivers/mtd/nand/Makefile    |   1 +
 drivers/mtd/nand/vf610_nfc.c | 640 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 656 insertions(+)
 create mode 100644 drivers/mtd/nand/vf610_nfc.c

Comments

Albert ARIBAUD July 30, 2015, 4:13 p.m. UTC | #1
Hi Stefan,

Le Mon, 27 Jul 2015 18:42:41 +0200, Stefan Agner <stefan@agner.ch> a
écrit :

> This driver supports Freescale NFC (NAND flash controller) found on
> Vybrid (VF610), MPC5125, MCF54418 and Kinetis K70. The driver has
> been tested on 8-bit and 16-bit NAND interface and supports ONFI
> parameter page reading.
> 
> [...]
> 
> diff --git a/drivers/mtd/nand/vf610_nfc.c b/drivers/mtd/nand/vf610_nfc.c
> new file mode 100644
> index 0000000..0da500e
> --- /dev/null
> +++ b/drivers/mtd/nand/vf610_nfc.c
> @@ -0,0 +1,640 @@
> [...]

... about line 708:

> +	err = devm_request_irq(nfc->dev, irq, vf610_nfc_irq, 0, DRV_NAME, mtd);
> +	if (err) {
> +		dev_err(nfc->dev, "Error requesting IRQ!\n");
> +		goto error;
> +	}
> +
> +	vf610_nfc_init_controller(nfc);

The call above is too early: vf610_nfc_init_controller() will test
for (nfc->chip.options & NAND_BUSWIDTH_16) but this option bit is only
set once nand_scan_ident() below has been run.

This has the effect that even when the DT node specifies a 16-bit wide
bus, the controller is configured for 8-bit mode at this point, which of
course causes read failures. I've experienced this with a Vybrid SoC
and a Micron MT29F4G16ABADAH4 16-bit NAND.

> +	/* first scan to find the device and get the page size */
> +	if (nand_scan_ident(mtd, 1, NULL)) {
> +		err = -ENXIO;
> +		goto error;
> +	}

Placing the call to vf610_nfc_init_controller() here, after the call
to nand_scan_ident() rather than before it, fixed the issue for me.

Cordialement,
Albert ARIBAUD
3ADEV
Stefan Agner July 30, 2015, 5 p.m. UTC | #2
Hi Albert,

On 2015-07-30 18:13, Albert ARIBAUD wrote:
> Hi Stefan,
> 
> Le Mon, 27 Jul 2015 18:42:41 +0200, Stefan Agner <stefan@agner.ch> a
> écrit :
> 
>> This driver supports Freescale NFC (NAND flash controller) found on
>> Vybrid (VF610), MPC5125, MCF54418 and Kinetis K70. The driver has
>> been tested on 8-bit and 16-bit NAND interface and supports ONFI
>> parameter page reading.
>>
>> [...]
>>
>> diff --git a/drivers/mtd/nand/vf610_nfc.c b/drivers/mtd/nand/vf610_nfc.c
>> new file mode 100644
>> index 0000000..0da500e
>> --- /dev/null
>> +++ b/drivers/mtd/nand/vf610_nfc.c
>> @@ -0,0 +1,640 @@
>> [...]
> 
> ... about line 708:
> 
>> +	err = devm_request_irq(nfc->dev, irq, vf610_nfc_irq, 0, DRV_NAME, mtd);
>> +	if (err) {
>> +		dev_err(nfc->dev, "Error requesting IRQ!\n");
>> +		goto error;
>> +	}
>> +
>> +	vf610_nfc_init_controller(nfc);
> 
> The call above is too early: vf610_nfc_init_controller() will test
> for (nfc->chip.options & NAND_BUSWIDTH_16) but this option bit is only
> set once nand_scan_ident() below has been run.
> 
> This has the effect that even when the DT node specifies a 16-bit wide
> bus, the controller is configured for 8-bit mode at this point, which of
> course causes read failures. I've experienced this with a Vybrid SoC
> and a Micron MT29F4G16ABADAH4 16-bit NAND.
> 
>> +	/* first scan to find the device and get the page size */
>> +	if (nand_scan_ident(mtd, 1, NULL)) {
>> +		err = -ENXIO;
>> +		goto error;
>> +	}
> 
> Placing the call to vf610_nfc_init_controller() here, after the call
> to nand_scan_ident() rather than before it, fixed the issue for me.

Hm, since nand_scan_ident access the devices we actually want the
controller initialized before we access it the first time. In most
cases, the boot loader/boot ROM probably initialized the controller in a
way that identifying the chip should work non the less. However, the
safe way would be to initialize it before calling nand_scan_ident.

However, I see your point regarding bus width: With the change to
nand_dt_init, we have that information after nand_scan_ident. There is
actually more: Also the HW ECC settings are not yet parsed at that
point, hence the ECC status and offset will not be initialized right. 

We could call the whole initialization twice. This would configure 8-Bit
mode for the 16-Bit devices, but during initialization this is anyway
the required default (ONFI). Or we split it up and call it something
like vf610_nfc_preinit_controller and vf610_nfc_init_controller.

What do you think?

--
Stefan
Albert ARIBAUD July 30, 2015, 8:11 p.m. UTC | #3
Hi Stefan,

Le Thu, 30 Jul 2015 19:00:38 +0200, Stefan Agner <stefan@agner.ch> a
écrit :

> Hi Albert,
> 
> On 2015-07-30 18:13, Albert ARIBAUD wrote:
> > Hi Stefan,
> > 
> > Le Mon, 27 Jul 2015 18:42:41 +0200, Stefan Agner <stefan@agner.ch> a
> > écrit :
> > 
> >> This driver supports Freescale NFC (NAND flash controller) found on
> >> Vybrid (VF610), MPC5125, MCF54418 and Kinetis K70. The driver has
> >> been tested on 8-bit and 16-bit NAND interface and supports ONFI
> >> parameter page reading.
> >>
> >> [...]
> >>
> >> diff --git a/drivers/mtd/nand/vf610_nfc.c b/drivers/mtd/nand/vf610_nfc.c
> >> new file mode 100644
> >> index 0000000..0da500e
> >> --- /dev/null
> >> +++ b/drivers/mtd/nand/vf610_nfc.c
> >> @@ -0,0 +1,640 @@
> >> [...]
> > 
> > ... about line 708:
> > 
> >> +	err = devm_request_irq(nfc->dev, irq, vf610_nfc_irq, 0, DRV_NAME, mtd);
> >> +	if (err) {
> >> +		dev_err(nfc->dev, "Error requesting IRQ!\n");
> >> +		goto error;
> >> +	}
> >> +
> >> +	vf610_nfc_init_controller(nfc);
> > 
> > The call above is too early: vf610_nfc_init_controller() will test
> > for (nfc->chip.options & NAND_BUSWIDTH_16) but this option bit is only
> > set once nand_scan_ident() below has been run.
> > 
> > This has the effect that even when the DT node specifies a 16-bit wide
> > bus, the controller is configured for 8-bit mode at this point, which of
> > course causes read failures. I've experienced this with a Vybrid SoC
> > and a Micron MT29F4G16ABADAH4 16-bit NAND.
> > 
> >> +	/* first scan to find the device and get the page size */
> >> +	if (nand_scan_ident(mtd, 1, NULL)) {
> >> +		err = -ENXIO;
> >> +		goto error;
> >> +	}
> > 
> > Placing the call to vf610_nfc_init_controller() here, after the call
> > to nand_scan_ident() rather than before it, fixed the issue for me.
> 
> Hm, since nand_scan_ident access the devices we actually want the
> controller initialized before we access it the first time. In most
> cases, the boot loader/boot ROM probably initialized the controller in a
> way that identifying the chip should work non the less. However, the
> safe way would be to initialize it before calling nand_scan_ident.

Correct -- there is a mutual dependency here between nand_scan_ident()
and vf610_nfc_init_controller(). Anyway, my call order switch was only
a hack to get things working.

> However, I see your point regarding bus width: With the change to
> nand_dt_init, we have that information after nand_scan_ident. There is
> actually more: Also the HW ECC settings are not yet parsed at that
> point, hence the ECC status and offset will not be initialized right. 
> 
> We could call the whole initialization twice. This would configure 8-Bit
> mode for the 16-Bit devices, but during initialization this is anyway
> the required default (ONFI). Or we split it up and call it something
> like vf610_nfc_preinit_controller and vf610_nfc_init_controller.
> 
> What do you think?

I think creating a vf610_nfc_preinit_controller() function with no
dependency on the DT is the cleaner option.

> --
> Stefan

Cordialement,
Albert ARIBAUD
3ADEV
diff mbox

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 9567329..59975c7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10835,6 +10835,12 @@  S:	Maintained
 F:	Documentation/fb/uvesafb.txt
 F:	drivers/video/fbdev/uvesafb.*
 
+VF610 NAND DRIVER
+M:	Stefan Agner <stefan@agner.ch>
+L:	linux-mtd@lists.infradead.org
+S:	Supported
+F:	drivers/mtd/nand/vf610_nfc.c
+
 VFAT/FAT/MSDOS FILESYSTEM
 M:	OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
 S:	Maintained
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 5b2806a..8550b14 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -463,6 +463,15 @@  config MTD_NAND_MPC5121_NFC
 	  This enables the driver for the NAND flash controller on the
 	  MPC5121 SoC.
 
+config MTD_NAND_VF610_NFC
+	tristate "Support for Freescale NFC for VF610/MPC5125"
+	depends on (SOC_VF610 || COMPILE_TEST)
+	help
+	  Enables support for NAND Flash Controller on some Freescale
+	  processors like the VF610, MPC5125, MCF54418 or Kinetis K70.
+	  The driver supports a maximum 2k page size. The driver
+	  currently does not support hardware ECC.
+
 config MTD_NAND_MXC
 	tristate "MXC NAND support"
 	depends on ARCH_MXC
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index 1f897ec..a490af8 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -45,6 +45,7 @@  obj-$(CONFIG_MTD_NAND_SOCRATES)		+= socrates_nand.o
 obj-$(CONFIG_MTD_NAND_TXX9NDFMC)	+= txx9ndfmc.o
 obj-$(CONFIG_MTD_NAND_NUC900)		+= nuc900_nand.o
 obj-$(CONFIG_MTD_NAND_MPC5121_NFC)	+= mpc5121_nfc.o
+obj-$(CONFIG_MTD_NAND_VF610_NFC)	+= vf610_nfc.o
 obj-$(CONFIG_MTD_NAND_RICOH)		+= r852.o
 obj-$(CONFIG_MTD_NAND_JZ4740)		+= jz4740_nand.o
 obj-$(CONFIG_MTD_NAND_GPMI_NAND)	+= gpmi-nand/
diff --git a/drivers/mtd/nand/vf610_nfc.c b/drivers/mtd/nand/vf610_nfc.c
new file mode 100644
index 0000000..0da500e
--- /dev/null
+++ b/drivers/mtd/nand/vf610_nfc.c
@@ -0,0 +1,640 @@ 
+/*
+ * Copyright 2009-2015 Freescale Semiconductor, Inc. and others
+ *
+ * Description: MPC5125, VF610, MCF54418 and Kinetis K70 Nand driver.
+ * Jason ported to M54418TWR and MVFA5 (VF610).
+ * Authors: Stefan Agner <stefan.agner@toradex.com>
+ *          Bill Pringlemeir <bpringlemeir@nbsps.com>
+ *          Shaohui Xie <b21989@freescale.com>
+ *          Jason Jin <Jason.jin@freescale.com>
+ *
+ * Based on original driver mpc5121_nfc.c.
+ *
+ * This 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.
+ *
+ * Limitations:
+ * - Untested on MPC5125 and M54418.
+ * - DMA not used.
+ * - 2K pages or less.
+ */
+
+#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/platform_device.h>
+#include <linux/slab.h>
+#include <linux/of_mtd.h>
+
+#define	DRV_NAME		"vf610_nfc"
+
+/* Register Offsets */
+#define NFC_FLASH_CMD1			0x3F00
+#define NFC_FLASH_CMD2			0x3F04
+#define NFC_COL_ADDR			0x3F08
+#define NFC_ROW_ADDR			0x3F0c
+#define NFC_ROW_ADDR_INC		0x3F14
+#define NFC_FLASH_STATUS1		0x3F18
+#define NFC_FLASH_STATUS2		0x3F1c
+#define NFC_CACHE_SWAP			0x3F28
+#define NFC_SECTOR_SIZE			0x3F2c
+#define NFC_FLASH_CONFIG		0x3F30
+#define NFC_IRQ_STATUS			0x3F38
+
+/* Addresses for NFC MAIN RAM BUFFER areas */
+#define NFC_MAIN_AREA(n)		((n) *  0x1000)
+
+#define PAGE_2K				0x0800
+#define OOB_64				0x0040
+
+/*
+ * NFC_CMD2[CODE] values. See section:
+ *  - 31.4.7 Flash Command Code Description, Vybrid manual
+ *  - 23.8.6 Flash Command Sequencer, MPC5125 manual
+ *
+ * Briefly these are bitmasks of controller cycles.
+ */
+#define READ_PAGE_CMD_CODE		0x7EE0
+#define READ_ONFI_PARAM_CMD_CODE	0x4860
+#define PROGRAM_PAGE_CMD_CODE		0x7FC0
+#define ERASE_CMD_CODE			0x4EC0
+#define READ_ID_CMD_CODE		0x4804
+#define RESET_CMD_CODE			0x4040
+#define STATUS_READ_CMD_CODE		0x4068
+
+/* NFC ECC mode define */
+#define ECC_BYPASS			0
+
+/*** Register Mask and bit definitions */
+
+/* NFC_FLASH_CMD1 Field */
+#define CMD_BYTE2_MASK				0xFF000000
+#define CMD_BYTE2_SHIFT				24
+
+/* NFC_FLASH_CM2 Field */
+#define CMD_BYTE1_MASK				0xFF000000
+#define CMD_BYTE1_SHIFT				24
+#define CMD_CODE_MASK				0x00FFFF00
+#define CMD_CODE_SHIFT				8
+#define BUFNO_MASK				0x00000006
+#define BUFNO_SHIFT				1
+#define START_BIT				(1<<0)
+
+/* NFC_COL_ADDR Field */
+#define COL_ADDR_MASK				0x0000FFFF
+#define COL_ADDR_SHIFT				0
+
+/* NFC_ROW_ADDR Field */
+#define ROW_ADDR_MASK				0x00FFFFFF
+#define ROW_ADDR_SHIFT				0
+#define ROW_ADDR_CHIP_SEL_RB_MASK		0xF0000000
+#define ROW_ADDR_CHIP_SEL_RB_SHIFT		28
+#define ROW_ADDR_CHIP_SEL_MASK			0x0F000000
+#define ROW_ADDR_CHIP_SEL_SHIFT			24
+
+/* NFC_FLASH_STATUS2 Field */
+#define STATUS_BYTE1_MASK			0x000000FF
+
+/* NFC_FLASH_CONFIG Field */
+#define CONFIG_ECC_SRAM_REQ_BIT			(1<<21)
+#define CONFIG_DMA_REQ_BIT			(1<<20)
+#define CONFIG_ECC_MODE_MASK			0x000E0000
+#define CONFIG_ECC_MODE_SHIFT			17
+#define CONFIG_FAST_FLASH_BIT			(1<<16)
+#define CONFIG_16BIT				(1<<7)
+#define CONFIG_BOOT_MODE_BIT			(1<<6)
+#define CONFIG_ADDR_AUTO_INCR_BIT		(1<<5)
+#define CONFIG_BUFNO_AUTO_INCR_BIT		(1<<4)
+#define CONFIG_PAGE_CNT_MASK			0xF
+#define CONFIG_PAGE_CNT_SHIFT			0
+
+/* NFC_IRQ_STATUS Field */
+#define IDLE_IRQ_BIT				(1<<29)
+#define IDLE_EN_BIT				(1<<20)
+#define CMD_DONE_CLEAR_BIT			(1<<18)
+#define IDLE_CLEAR_BIT				(1<<17)
+
+struct vf610_nfc {
+	struct mtd_info mtd;
+	struct nand_chip chip;
+	struct device *dev;
+	void __iomem *regs;
+	struct completion cmd_done;
+	uint buf_offset;
+	int page_sz;
+	/* Status and ID are in alternate locations. */
+	int alt_buf;
+#define ALT_BUF_ID   1
+#define ALT_BUF_STAT 2
+#define ALT_BUF_ONFI 3
+	struct clk *clk;
+};
+
+#define mtd_to_nfc(_mtd) container_of(_mtd, struct vf610_nfc, mtd)
+
+static inline u32 vf610_nfc_read(struct vf610_nfc *nfc, uint reg)
+{
+	return readl(nfc->regs + reg);
+}
+
+static inline void vf610_nfc_write(struct vf610_nfc *nfc, uint reg, u32 val)
+{
+	writel(val, nfc->regs + reg);
+}
+
+static inline void vf610_nfc_set(struct vf610_nfc *nfc, uint reg, u32 bits)
+{
+	vf610_nfc_write(nfc, reg, vf610_nfc_read(nfc, reg) | bits);
+}
+
+static inline void vf610_nfc_clear(struct vf610_nfc *nfc, uint reg, u32 bits)
+{
+	vf610_nfc_write(nfc, reg, vf610_nfc_read(nfc, reg) & ~bits);
+}
+
+static inline void vf610_nfc_set_field(struct vf610_nfc *nfc, u32 reg,
+				       u32 mask, u32 shift, u32 val)
+{
+	vf610_nfc_write(nfc, reg,
+			(vf610_nfc_read(nfc, reg) & (~mask)) | val << shift);
+}
+
+static inline void vf610_nfc_memcpy(void *dst, const void *src, size_t n)
+{
+	/*
+	 * Use this accessor for the internal SRAM buffers. On the ARM
+	 * Freescale Vybrid SoC it's known that the driver can treat
+	 * the SRAM buffer as if it's memory. Other platform might need
+	 * to treat the buffers differently.
+	 *
+	 * For the time being, use memcpy
+	 */
+	memcpy(dst, src, n);
+}
+
+/* Clear flags for upcoming command */
+static inline void vf610_nfc_clear_status(struct vf610_nfc *nfc)
+{
+	u32 tmp = vf610_nfc_read(nfc, NFC_IRQ_STATUS);
+
+	tmp |= CMD_DONE_CLEAR_BIT | IDLE_CLEAR_BIT;
+	vf610_nfc_write(nfc, NFC_IRQ_STATUS, tmp);
+}
+
+static inline void vf610_nfc_done(struct vf610_nfc *nfc)
+{
+	unsigned long timeout = msecs_to_jiffies(100);
+
+	/*
+	 * Barrier is needed after this write. This write need
+	 * to be done before reading the next register the first
+	 * time.
+	 * vf610_nfc_set implicates such a barrier by using writel
+	 * to write to the register.
+	 */
+	vf610_nfc_set(nfc, NFC_IRQ_STATUS, IDLE_EN_BIT);
+	vf610_nfc_set(nfc, NFC_FLASH_CMD2, START_BIT);
+
+	if (!(vf610_nfc_read(nfc, NFC_IRQ_STATUS) & IDLE_IRQ_BIT)) {
+		if (!wait_for_completion_timeout(&nfc->cmd_done, timeout))
+			dev_warn(nfc->dev, "Timeout while waiting for BUSY.\n");
+	}
+	vf610_nfc_clear_status(nfc);
+}
+
+static u8 vf610_nfc_get_id(struct vf610_nfc *nfc, int col)
+{
+	u32 flash_id;
+
+	if (col < 4) {
+		flash_id = vf610_nfc_read(nfc, NFC_FLASH_STATUS1);
+		flash_id >>= (3 - col) * 8;
+	} else {
+		flash_id = vf610_nfc_read(nfc, NFC_FLASH_STATUS2);
+		flash_id >>= 24;
+	}
+
+	return flash_id & 0xff;
+}
+
+static u8 vf610_nfc_get_status(struct vf610_nfc *nfc)
+{
+	return vf610_nfc_read(nfc, NFC_FLASH_STATUS2) & STATUS_BYTE1_MASK;
+}
+
+static void vf610_nfc_send_command(struct vf610_nfc *nfc, u32 cmd_byte1,
+				   u32 cmd_code)
+{
+	u32 tmp;
+
+	vf610_nfc_clear_status(nfc);
+
+	tmp = vf610_nfc_read(nfc, NFC_FLASH_CMD2);
+	tmp &= ~(CMD_BYTE1_MASK | CMD_CODE_MASK | BUFNO_MASK);
+	tmp |= cmd_byte1 << CMD_BYTE1_SHIFT;
+	tmp |= cmd_code << CMD_CODE_SHIFT;
+	vf610_nfc_write(nfc, NFC_FLASH_CMD2, tmp);
+}
+
+static void vf610_nfc_send_commands(struct vf610_nfc *nfc, u32 cmd_byte1,
+				    u32 cmd_byte2, u32 cmd_code)
+{
+	u32 tmp;
+
+	vf610_nfc_send_command(nfc, cmd_byte1, cmd_code);
+
+	tmp = vf610_nfc_read(nfc, NFC_FLASH_CMD1);
+	tmp &= ~CMD_BYTE2_MASK;
+	tmp |= cmd_byte2 << CMD_BYTE2_SHIFT;
+	vf610_nfc_write(nfc, NFC_FLASH_CMD1, tmp);
+}
+
+static irqreturn_t vf610_nfc_irq(int irq, void *data)
+{
+	struct mtd_info *mtd = data;
+	struct vf610_nfc *nfc = mtd_to_nfc(mtd);
+
+	vf610_nfc_clear(nfc, NFC_IRQ_STATUS, IDLE_EN_BIT);
+	complete(&nfc->cmd_done);
+
+	return IRQ_HANDLED;
+}
+
+static void vf610_nfc_addr_cycle(struct vf610_nfc *nfc, int column, int page)
+{
+	if (column != -1) {
+		if (nfc->chip.options & NAND_BUSWIDTH_16)
+			column = column / 2;
+		vf610_nfc_set_field(nfc, NFC_COL_ADDR, COL_ADDR_MASK,
+				    COL_ADDR_SHIFT, column);
+	}
+	if (page != -1)
+		vf610_nfc_set_field(nfc, NFC_ROW_ADDR, ROW_ADDR_MASK,
+				    ROW_ADDR_SHIFT, page);
+}
+
+static inline void vf610_nfc_transfer_size(struct vf610_nfc *nfc, int size)
+{
+	vf610_nfc_write(nfc, NFC_SECTOR_SIZE, size);
+}
+
+static void vf610_nfc_command(struct mtd_info *mtd, unsigned command,
+			      int column, int page)
+{
+	struct vf610_nfc *nfc = mtd_to_nfc(mtd);
+	int page_sz = nfc->chip.options & NAND_BUSWIDTH_16 ? 1 : 0;
+
+	nfc->buf_offset = max(column, 0);
+	nfc->alt_buf = 0;
+
+	switch (command) {
+	case NAND_CMD_SEQIN:
+		/* Use valid column/page from preread... */
+		vf610_nfc_addr_cycle(nfc, column, page);
+		/*
+		 * SEQIN => data => PAGEPROG sequence is done by the controller
+		 * hence we do not need to issue the command here...
+		 */
+		return;
+	case NAND_CMD_PAGEPROG:
+		page_sz += mtd->writesize + mtd->oobsize;
+		vf610_nfc_transfer_size(nfc, page_sz);
+		vf610_nfc_send_commands(nfc, NAND_CMD_SEQIN,
+					command, PROGRAM_PAGE_CMD_CODE);
+		break;
+
+	case NAND_CMD_RESET:
+		vf610_nfc_transfer_size(nfc, 0);
+		vf610_nfc_send_command(nfc, command, RESET_CMD_CODE);
+		break;
+
+	case NAND_CMD_READOOB:
+		page_sz += mtd->oobsize;
+		column = mtd->writesize;
+		vf610_nfc_transfer_size(nfc, page_sz);
+		vf610_nfc_send_commands(nfc, NAND_CMD_READ0,
+					NAND_CMD_READSTART, READ_PAGE_CMD_CODE);
+		vf610_nfc_addr_cycle(nfc, column, page);
+		break;
+
+	case NAND_CMD_READ0:
+		page_sz += mtd->writesize + mtd->oobsize;
+		vf610_nfc_transfer_size(nfc, page_sz);
+		vf610_nfc_send_commands(nfc, NAND_CMD_READ0,
+					NAND_CMD_READSTART, READ_PAGE_CMD_CODE);
+		vf610_nfc_addr_cycle(nfc, column, page);
+		break;
+
+	case NAND_CMD_PARAM:
+		nfc->alt_buf = ALT_BUF_ONFI;
+		vf610_nfc_transfer_size(nfc, 768);
+		vf610_nfc_send_command(nfc, command, READ_ONFI_PARAM_CMD_CODE);
+		vf610_nfc_set_field(nfc, NFC_ROW_ADDR, ROW_ADDR_MASK,
+				    ROW_ADDR_SHIFT, column);
+		break;
+
+	case NAND_CMD_ERASE1:
+		vf610_nfc_transfer_size(nfc, 0);
+		vf610_nfc_send_commands(nfc, command,
+					NAND_CMD_ERASE2, ERASE_CMD_CODE);
+		vf610_nfc_addr_cycle(nfc, column, page);
+		break;
+
+	case NAND_CMD_READID:
+		nfc->alt_buf = ALT_BUF_ID;
+		nfc->buf_offset = 0;
+		vf610_nfc_transfer_size(nfc, 0);
+		vf610_nfc_send_command(nfc, command, READ_ID_CMD_CODE);
+		vf610_nfc_set_field(nfc, NFC_ROW_ADDR, ROW_ADDR_MASK,
+				    ROW_ADDR_SHIFT, column);
+		break;
+
+	case NAND_CMD_STATUS:
+		nfc->alt_buf = ALT_BUF_STAT;
+		vf610_nfc_transfer_size(nfc, 0);
+		vf610_nfc_send_command(nfc, command, STATUS_READ_CMD_CODE);
+		break;
+	default:
+		return;
+	}
+
+	vf610_nfc_done(nfc);
+}
+
+static void vf610_nfc_read_buf(struct mtd_info *mtd, u_char *buf, int len)
+{
+	struct vf610_nfc *nfc = mtd_to_nfc(mtd);
+	uint c = nfc->buf_offset;
+
+	/* Alternate buffers are only supported through read_byte */
+	WARN_ON(nfc->alt_buf);
+
+	vf610_nfc_memcpy(buf, nfc->regs + NFC_MAIN_AREA(0) + c, len);
+
+	nfc->buf_offset += len;
+}
+
+static void vf610_nfc_write_buf(struct mtd_info *mtd, const uint8_t *buf,
+				int len)
+{
+	struct vf610_nfc *nfc = mtd_to_nfc(mtd);
+	uint c = nfc->buf_offset;
+	uint l;
+
+	l = min_t(uint, len, mtd->writesize + mtd->oobsize - c);
+	vf610_nfc_memcpy(nfc->regs + NFC_MAIN_AREA(0) + c, buf, l);
+
+	nfc->buf_offset += l;
+}
+
+static uint8_t vf610_nfc_read_byte(struct mtd_info *mtd)
+{
+	struct vf610_nfc *nfc = mtd_to_nfc(mtd);
+	u8 tmp;
+	uint c = nfc->buf_offset;
+
+	switch (nfc->alt_buf) {
+	case ALT_BUF_ID:
+		tmp = vf610_nfc_get_id(nfc, c);
+		break;
+	case ALT_BUF_STAT:
+		tmp = vf610_nfc_get_status(nfc);
+		break;
+#ifdef __LITTLE_ENDIAN
+	case ALT_BUF_ONFI:
+		/* Reverse byte since the controller uses big endianness */
+		c = nfc->buf_offset ^ 0x3;
+		tmp = *((u8 *)(nfc->regs + NFC_MAIN_AREA(0) + c));
+		break;
+#endif
+	default:
+		tmp = *((u8 *)(nfc->regs + NFC_MAIN_AREA(0) + c));
+		break;
+	}
+	nfc->buf_offset++;
+	return tmp;
+}
+
+static u16 vf610_nfc_read_word(struct mtd_info *mtd)
+{
+	u16 tmp;
+
+	vf610_nfc_read_buf(mtd, (u_char *)&tmp, sizeof(tmp));
+	return tmp;
+}
+
+/* If not provided, upper layers apply a fixed delay. */
+static int vf610_nfc_dev_ready(struct mtd_info *mtd)
+{
+	/* NFC handles R/B internally; always ready.  */
+	return 1;
+}
+
+/*
+ * This function supports Vybrid only (MPC5125 would have full RB and four CS)
+ */
+static void vf610_nfc_select_chip(struct mtd_info *mtd, int chip)
+{
+#ifdef CONFIG_SOC_VF610
+	struct vf610_nfc *nfc = mtd_to_nfc(mtd);
+	u32 tmp = vf610_nfc_read(nfc, NFC_ROW_ADDR);
+
+	tmp &= ~(ROW_ADDR_CHIP_SEL_RB_MASK | ROW_ADDR_CHIP_SEL_MASK);
+	tmp |= 1 << ROW_ADDR_CHIP_SEL_RB_SHIFT;
+
+	if (chip == 0)
+		tmp |= 1 << ROW_ADDR_CHIP_SEL_SHIFT;
+	else if (chip == 1)
+		tmp |= 2 << ROW_ADDR_CHIP_SEL_SHIFT;
+
+	vf610_nfc_write(nfc, NFC_ROW_ADDR, tmp);
+#endif
+}
+
+static const struct of_device_id vf610_nfc_dt_ids[] = {
+	{ .compatible = "fsl,vf610-nfc" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, vf610_nfc_dt_ids);
+
+static int vf610_nfc_init_controller(struct vf610_nfc *nfc)
+{
+	if (nfc->chip.options & NAND_BUSWIDTH_16)
+		vf610_nfc_set(nfc, NFC_FLASH_CONFIG, CONFIG_16BIT);
+	else
+		vf610_nfc_clear(nfc, NFC_FLASH_CONFIG, CONFIG_16BIT);
+
+	/* Set configuration register. */
+	vf610_nfc_clear(nfc, NFC_FLASH_CONFIG, CONFIG_ADDR_AUTO_INCR_BIT);
+	vf610_nfc_clear(nfc, NFC_FLASH_CONFIG, CONFIG_BUFNO_AUTO_INCR_BIT);
+	vf610_nfc_clear(nfc, NFC_FLASH_CONFIG, CONFIG_BOOT_MODE_BIT);
+	vf610_nfc_clear(nfc, NFC_FLASH_CONFIG, CONFIG_DMA_REQ_BIT);
+	vf610_nfc_set(nfc, NFC_FLASH_CONFIG, CONFIG_FAST_FLASH_BIT);
+
+	/* PAGE_CNT = 1 */
+	vf610_nfc_set_field(nfc, NFC_FLASH_CONFIG, CONFIG_PAGE_CNT_MASK,
+			    CONFIG_PAGE_CNT_SHIFT, 1);
+
+	return 0;
+}
+
+static int vf610_nfc_probe(struct platform_device *pdev)
+{
+	struct vf610_nfc *nfc;
+	struct resource *res;
+	struct mtd_info *mtd;
+	struct nand_chip *chip;
+	int err = 0;
+	int irq;
+
+	nfc = devm_kzalloc(&pdev->dev, sizeof(*nfc), GFP_KERNEL);
+	if (!nfc)
+		return -ENOMEM;
+
+	nfc->dev = &pdev->dev;
+	mtd = &nfc->mtd;
+	chip = &nfc->chip;
+
+	mtd->priv = chip;
+	mtd->owner = THIS_MODULE;
+	mtd->dev.parent = nfc->dev;
+	mtd->name = DRV_NAME;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq <= 0)
+		return -EINVAL;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	nfc->regs = devm_ioremap_resource(nfc->dev, res);
+	if (IS_ERR(nfc->regs))
+		return PTR_ERR(nfc->regs);
+
+	nfc->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(nfc->clk))
+		return PTR_ERR(nfc->clk);
+
+	err = clk_prepare_enable(nfc->clk);
+	if (err) {
+		dev_err(nfc->dev, "Unable to enable clock!\n");
+		return err;
+	}
+
+	chip->dn = nfc->dev->of_node;
+	chip->dev_ready = vf610_nfc_dev_ready;
+	chip->cmdfunc = vf610_nfc_command;
+	chip->read_byte = vf610_nfc_read_byte;
+	chip->read_word = vf610_nfc_read_word;
+	chip->read_buf = vf610_nfc_read_buf;
+	chip->write_buf = vf610_nfc_write_buf;
+	chip->select_chip = vf610_nfc_select_chip;
+
+	chip->options |= NAND_NO_SUBPAGE_WRITE;
+
+	init_completion(&nfc->cmd_done);
+
+	err = devm_request_irq(nfc->dev, irq, vf610_nfc_irq, 0, DRV_NAME, mtd);
+	if (err) {
+		dev_err(nfc->dev, "Error requesting IRQ!\n");
+		goto error;
+	}
+
+	vf610_nfc_init_controller(nfc);
+
+	/* first scan to find the device and get the page size */
+	if (nand_scan_ident(mtd, 1, NULL)) {
+		err = -ENXIO;
+		goto error;
+	}
+
+	/* Bad block options. */
+	if (chip->bbt_options & NAND_BBT_USE_FLASH)
+		chip->bbt_options |= NAND_BBT_NO_OOB;
+
+	/* Single buffer only, max 256 OOB minus ECC status */
+	if (mtd->writesize + mtd->oobsize > PAGE_2K + 256 - 8) {
+		dev_err(nfc->dev, "Unsupported flash page size\n");
+		err = -ENXIO;
+		goto error;
+	}
+
+	/* second phase scan */
+	if (nand_scan_tail(mtd)) {
+		err = -ENXIO;
+		goto error;
+	}
+
+	/* Register device in MTD */
+	mtd_device_parse_register(mtd, NULL,
+		&(struct mtd_part_parser_data){
+			.of_node = pdev->dev.of_node,
+		},
+		NULL, 0);
+
+	platform_set_drvdata(pdev, mtd);
+
+	return 0;
+
+error:
+	clk_disable_unprepare(nfc->clk);
+	return err;
+}
+
+static int vf610_nfc_remove(struct platform_device *pdev)
+{
+	struct mtd_info *mtd = platform_get_drvdata(pdev);
+	struct vf610_nfc *nfc = mtd_to_nfc(mtd);
+
+	nand_release(mtd);
+	clk_disable_unprepare(nfc->clk);
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int vf610_nfc_suspend(struct device *dev)
+{
+	struct mtd_info *mtd = dev_get_drvdata(dev);
+	struct vf610_nfc *nfc = mtd_to_nfc(mtd);
+
+	clk_disable_unprepare(nfc->clk);
+	return 0;
+}
+
+static int vf610_nfc_resume(struct device *dev)
+{
+	struct mtd_info *mtd = dev_get_drvdata(dev);
+	struct vf610_nfc *nfc = mtd_to_nfc(mtd);
+
+	pinctrl_pm_select_default_state(dev);
+
+	clk_prepare_enable(nfc->clk);
+
+	vf610_nfc_init_controller(nfc);
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(vf610_nfc_pm_ops, vf610_nfc_suspend, vf610_nfc_resume);
+
+static struct platform_driver vf610_nfc_driver = {
+	.driver		= {
+		.name	= DRV_NAME,
+		.of_match_table = vf610_nfc_dt_ids,
+		.pm	= &vf610_nfc_pm_ops,
+	},
+	.probe		= vf610_nfc_probe,
+	.remove		= vf610_nfc_remove,
+};
+
+module_platform_driver(vf610_nfc_driver);
+
+MODULE_AUTHOR("Stefan Agner <stefan.agner@toradex.com>");
+MODULE_DESCRIPTION("Freescale VF610/MPC5125 NFC MTD NAND driver");
+MODULE_LICENSE("GPL");