AT91SAM9 NAND flash driver.

This creates the TCL interface for configuring an AT91SAM9 NAND flash
controller and implements the necessary functions to correctly work with
a NAND flash device connected to the chip.  This includes updates to the
driver list and the Makefile.am to support building the driver and also
houses the documentation update in openocd.texi.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

4 files changed, 789 insertions, 1 deletions

diff --git a/doc/openocd.texi b/doc/openocd.texi
index d9cb4ea6..4244a1e8 100644
--- a/doc/openocd.texi
+++ b/doc/openocd.texi
@@ -4812,6 +4812,41 @@ As noted above, the @command{nand device} command allows
 driver-specific options and behaviors.
 Some controllers also activate controller-specific commands.
 
+@deffn {NAND Driver} at91sam9
+This driver handles the NAND controllers found on AT91SAM9 family chips from
+Atmel.  It takes two extra parameters: address of the NAND chip;
+address of the ECC controller.
+@example
+nand device $NANDFLASH at91sam9 $CHIPNAME 0x40000000 0xfffffe800
+@end example
+AT91SAM9 chips support single-bit ECC hardware. The @code{write_page} and
+@code{read_page} methods are used to utilize the ECC hardware unless they are
+disabled by using the @command{nand raw_access} command.  There are four 
+additional commands that are needed to fully configure the AT91SAM9 NAND
+controller.  Two are optional; most boards use the same wiring for ALE/CLE:
+@deffn Command {at91sam9 cle} num addr_line
+Configure the address line used for latching commands.  The @var{num} 
+parameter is the value shown by @command{nand list}.
+@end deffn
+@deffn Command {at91sam9 ale} num addr_line
+Configure the address line used for latching addresses.  The @var{num} 
+parameter is the value shown by @command{nand list}.
+@end deffn
+
+For the next two commands, it is assumed that the pins have already been 
+properly configured for input or output.
+@deffn Command {at91sam9 rdy_busy} num pio_base_addr pin
+Configure the RDY/nBUSY input from the NAND device.  The @var{num} 
+parameter is the value shown by @command{nand list}.  @var{pio_base_addr} 
+is the base address of the PIO controller and @var{pin} is the pin number.
+@end deffn
+@deffn Command {at91sam9 ce} num pio_base_addr pin
+Configure the chip enable input to the NAND device.  The @var{num} 
+parameter is the value shown by @command{nand list}.  @var{pio_base_addr} 
+is the base address of the PIO controller and @var{pin} is the pin number.
+@end deffn
+@end deffn
+
 @deffn {NAND Driver} davinci
 This driver handles the NAND controllers found on DaVinci family
 chips from Texas Instruments.
diff --git a/src/flash/nand/Makefile.am b/src/flash/nand/Makefile.am
index f3033b85..bb9998e5 100644
--- a/src/flash/nand/Makefile.am
+++ b/src/flash/nand/Makefile.am
@@ -24,7 +24,8 @@ NAND_DRIVERS = \
 	s3c2410.c \
 	s3c2412.c \
 	s3c2440.c \
-	s3c2443.c
+	s3c2443.c \
+	at91sam9.c
 
 noinst_HEADERS = \
 	arm_io.h \
diff --git a/src/flash/nand/at91sam9.c b/src/flash/nand/at91sam9.c
new file mode 100644
index 00000000..7cfd763a
--- /dev/null
+++ b/src/flash/nand/at91sam9.c
@@ -0,0 +1,750 @@
+/*
+ * Copyright (C) 2009 by Dean Glazeski
+ * dnglaze@gmail.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.,
+ * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <target/arm.h>
+#include <helper/log.h>
+#include "imp.h"
+#include "arm_io.h"
+
+#define AT91C_PIOx_SODR (0x30) /**< Offset to PIO SODR. */
+#define AT91C_PIOx_CODR (0x34) /**< Offset to PIO CODR. */
+#define AT91C_PIOx_PDSR (0x3C) /**< Offset to PIO PDSR. */
+#define AT91C_ECCx_CR (0x00) /**< Offset to ECC CR. */
+#define AT91C_ECCx_SR (0x08) /**< Offset to ECC SR. */
+#define AT91C_ECCx_PR (0x0C) /**< Offset to ECC PR. */
+#define AT91C_ECCx_NPR (0x10) /**< Offset to ECC NPR. */
+
+/**
+ * Representation of a pin on an AT91SAM9 chip.
+ */
+struct at91sam9_pin {
+	/** Target this pin is on. */
+	struct target *target;
+
+	/** Address of the PIO controller. */
+	uint32_t pioc;
+
+	/** Pin number. */
+	uint32_t num;
+};
+
+/**
+ * Private data for the controller that is stored in the NAND device structure.
+ */
+struct at91sam9_nand {
+	/** Target the NAND is attached to. */
+	struct target *target;
+
+	/** Address of the ECC controller for NAND. */
+	uint32_t ecc;
+
+	/** Address data is written to. */
+	uint32_t data;
+
+	/** Address commands are written to. */
+	uint32_t cmd;
+
+	/** Address addresses are written to. */
+	uint32_t addr;
+
+	/** I/O structure for hosted reads/writes. */
+	struct arm_nand_data io;
+
+	/** Pin representing the ready/~busy line. */
+	struct at91sam9_pin busy;
+
+	/** Pin representing the chip enable. */
+	struct at91sam9_pin ce;
+};
+
+/**
+ * Checks if the target is halted and prints an error message if it isn't.
+ *
+ * @param target Target to be checked.
+ * @param label String label for where function is called from.
+ * @return True if the target is halted.
+ */
+static int at91sam9_halted(struct target *target, const char *label)
+{
+	if (target->state == TARGET_HALTED)
+		return true;
+
+	LOG_ERROR("Target must be halted to use NAND controller (%s)", label);
+	return false;
+}
+
+/**
+ * Initialize the AT91SAM9 NAND controller.
+ *
+ * @param nand NAND device the controller is attached to.
+ * @return Success or failure of initialization.
+ */
+static int at91sam9_init(struct nand_device *nand)
+{
+	struct at91sam9_nand *info = nand->controller_priv;
+	struct target *target = info->target;
+
+	if (!at91sam9_halted(target, "init")) {
+		return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	return ERROR_OK;
+}
+
+/**
+ * Enable NAND device attached to a controller.
+ *
+ * @param info NAND controller information for controlling NAND device.
+ * @return Success or failure of the enabling.
+ */
+static int at91sam9_enable(struct at91sam9_nand *info)
+{
+	struct target *target = info->target;
+
+	return target_write_u32(target, info->ce.pioc + AT91C_PIOx_CODR, 1 << info->ce.num);
+}
+
+/**
+ * Disable NAND device attached to a controller.
+ *
+ * @param info NAND controller information for controlling NAND device.
+ * @return Success or failure of the disabling.
+ */
+static int at91sam9_disable(struct at91sam9_nand *info)
+{
+	struct target *target = info->target;
+
+	return target_write_u32(target, info->ce.pioc + AT91C_PIOx_SODR, 1 << info->ce.num);
+}
+
+/**
+ * Send a command to the NAND device.
+ *
+ * @param nand NAND device to write the command to.
+ * @param command Command to be written.
+ * @return Success or failure of writing the command.
+ */
+static int at91sam9_command(struct nand_device *nand, uint8_t command)
+{
+	struct at91sam9_nand *info = nand->controller_priv;
+	struct target *target = info->target;
+
+	if (!at91sam9_halted(target, "command")) {
+		return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	at91sam9_enable(info);
+
+	return target_write_u8(target, info->cmd, command);
+}
+
+/**
+ * Reset the AT91SAM9 NAND controller.
+ *
+ * @param nand NAND device to be reset.
+ * @return Success or failure of reset.
+ */
+static int at91sam9_reset(struct nand_device *nand)
+{
+	struct at91sam9_nand *info = nand->controller_priv;
+
+	if (!at91sam9_halted(info->target, "reset")) {
+		return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	return at91sam9_disable(info);
+}
+
+/**
+ * Send an address to the NAND device attached to an AT91SAM9 NAND controller.
+ *
+ * @param nand NAND device to send the address to.
+ * @param address Address to be sent.
+ * @return Success or failure of sending the address.
+ */
+static int at91sam9_address(struct nand_device *nand, uint8_t address)
+{
+	struct at91sam9_nand *info = nand->controller_priv;
+	struct target *target = info->target;
+
+	if (!at91sam9_halted(info->target, "address")) {
+		return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	return target_write_u8(target, info->addr, address);
+}
+
+/**
+ * Read data directly from the NAND device attached to an AT91SAM9 NAND
+ * controller.
+ *
+ * @param nand NAND device to read from.
+ * @param data Pointer to where the data should be put.
+ * @return Success or failure of reading the data.
+ */
+static int at91sam9_read_data(struct nand_device *nand, void *data)
+{
+	struct at91sam9_nand *info = nand->controller_priv;
+	struct target *target = info->target;
+
+	if (!at91sam9_halted(info->target, "read data")) {
+		return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	return target_read_u8(target, info->data, data);
+}
+
+/**
+ * Write data directly to the NAND device attached to an AT91SAM9 NAND
+ * controller.
+ *
+ * @param nand NAND device to be written to.
+ * @param data Data to be written.
+ * @return Success or failure of the data write.
+ */
+static int at91sam9_write_data(struct nand_device *nand, uint16_t data)
+{
+	struct at91sam9_nand *info = nand->controller_priv;
+	struct target *target = info->target;
+
+	if (!at91sam9_halted(target, "write data")) {
+		return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	return target_write_u8(target, info->data, data);
+}
+
+/**
+ * Determine if the NAND device is ready by looking at the ready/~busy pin.
+ *
+ * @param nand NAND device to check.
+ * @param timeout Time in milliseconds to wait for NAND to be ready.
+ * @return True if the NAND is ready in the timeout period.
+ */
+static int at91sam9_nand_ready(struct nand_device *nand, int timeout)
+{
+	struct at91sam9_nand *info = nand->controller_priv;
+	struct target *target = info->target;
+	uint32_t status;
+
+	if (!at91sam9_halted(target, "nand ready")) {
+		return 0;
+	}
+
+	do {
+		target_read_u32(target, info->busy.pioc + AT91C_PIOx_PDSR, &status);
+
+		if (status & (1 << info->busy.num)) {
+			return 1;
+		}
+
+		alive_sleep(1);
+	} while (timeout-- > 0);
+
+	return 0;
+}
+
+/**
+ * Read a block of data from the NAND device attached to an AT91SAM9.  This
+ * utilizes the ARM hosted NAND read function.
+ *
+ * @param nand NAND device to read from.
+ * @param data Pointer to where the read data should be placed.
+ * @param size Size of the data being read.
+ * @return Success or failure of the hosted read.
+ */
+static int at91sam9_read_block_data(struct nand_device *nand, uint8_t *data, int size)
+{
+	struct at91sam9_nand *info = nand->controller_priv;
+	struct arm_nand_data *io = &info->io;
+	int status;
+
+	if (!at91sam9_halted(info->target, "read block")) {
+		return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	io->chunk_size = nand->page_size;
+	status = arm_nandread(io, data, size);
+
+	return status;
+}
+
+/**
+ * Write a block of data to a NAND device attached to an AT91SAM9.  This uses
+ * the ARM hosted write function to write the data.
+ *
+ * @param nand NAND device to write to.
+ * @param data Data to be written to device.
+ * @param size Size of the data being written.
+ * @return Success or failure of the hosted write.
+ */
+static int at91sam9_write_block_data(struct nand_device *nand, uint8_t *data, int size)
+{
+	struct at91sam9_nand *info = nand->controller_priv;
+	struct arm_nand_data *io = &info->io;
+	int status;
+
+	if (!at91sam9_halted(info->target, "write block")) {
+		return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	io->chunk_size = nand->page_size;
+	status = arm_nandwrite(io, data, size);
+
+	return status;
+}
+
+/**
+ * Initialize the ECC controller on the AT91SAM9.
+ *
+ * @param target Target to configure ECC on.
+ * @param info NAND controller information for where the ECC is.
+ * @return Success or failure of initialization.
+ */
+static int at91sam9_ecc_init(struct target *target, struct at91sam9_nand *info)
+{
+	if (!info->ecc) {
+		LOG_ERROR("ECC controller address must be set when not reading raw NAND data");
+		return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	// reset ECC parity registers
+	return target_write_u32(target, info->ecc + AT91C_ECCx_CR, 1);
+}
+
+/**
+ * Initialize an area for the OOB based on whether a user is requesting the OOB
+ * data.  This determines the size of the OOB and allocates the space in case
+ * the user has not requested the OOB data.
+ *
+ * @param nand NAND device we are creating an OOB for.
+ * @param oob Pointer to the user supplied OOB area.
+ * @param size Size of the OOB.
+ * @return Pointer to an area to store OOB data.
+ */
+static uint8_t * at91sam9_oob_init(struct nand_device *nand, uint8_t *oob, uint32_t *size)
+{
+	if (!oob) {
+		// user doesn't want OOB, allocate it
+		if (nand->page_size == 512) {
+			*size = 16;
+		} else if (nand->page_size == 2048) {
+			*size = 64;
+		}
+
+		oob = malloc(*size);
+		if (!oob) {
+			LOG_ERROR("Unable to allocate space for OOB");
+		}
+
+		memset(oob, 0xFF, *size);
+	}
+
+	return oob;
+}
+
+/**
+ * Reads a page from an AT91SAM9 NAND controller and verifies using 1-bit ECC
+ * controller on chip.  This makes an attempt to correct any errors that are
+ * encountered while reading the page of data.
+ *
+ * @param nand NAND device to read from
+ * @param page Page to be read.
+ * @param data Pointer to where data should be read to.
+ * @param data_size Size of the data to be read.
+ * @param oob Pointer to where OOB data should be read to.
+ * @param oob_size Size of the OOB data to be read.
+ * @return Success or failure of reading the NAND page.
+ */
+static int at91sam9_read_page(struct nand_device *nand, uint32_t page,
+		uint8_t *data, uint32_t data_size, uint8_t *oob, uint32_t oob_size)
+{
+	int retval;
+	struct at91sam9_nand *info = nand->controller_priv;
+	struct target *target = info->target;
+	uint8_t *oob_data;
+	uint32_t status;
+
+	retval = at91sam9_ecc_init(target, info);
+	if (ERROR_OK != retval) {
+		return retval;
+	}
+
+	retval = nand_page_command(nand, page, NAND_CMD_READ0, !data);
+	if (ERROR_OK != retval) {
+		return retval;
+	}
+
+	if (data) {
+		retval = nand_read_data_page(nand, data, data_size);
+		if (ERROR_OK != retval) {
+			return retval;
+		}
+	}
+
+	oob_data = at91sam9_oob_init(nand, oob, &oob_size);
+	retval = nand_read_data_page(nand, oob_data, oob_size);
+	if (ERROR_OK == retval && data) {
+		target_read_u32(target, info->ecc + AT91C_ECCx_SR, &status);
+		if (status & 1) {
+			LOG_ERROR("Error detected!");
+			if (status & 4) {
+				LOG_ERROR("Multiple errors encountered; unrecoverable!");
+			} else {
+				// attempt recovery
+				uint32_t parity;
+
+				target_read_u32(target, info->ecc + AT91C_ECCx_PR, &parity);
+				uint32_t word = (parity & 0x0000FFF0) >> 4;
+				uint32_t bit = parity & 0x0F;
+
+				data[word] ^= (0x1) << bit;
+				LOG_INFO("Data word %d, bit %d corrected.", word, bit);
+			}
+		}
+
+		if (status & 2) {
+			// we could write back correct ECC data
+			LOG_ERROR("Error in ECC bytes detected");
+		}
+	}
+
+	if (!oob) {
+		// if it wasn't asked for, free it
+		free(oob_data);
+	}
+
+	return retval;
+}
+
+/**
+ * Write a page of data including 1-bit ECC information to a NAND device
+ * attached to an AT91SAM9 controller.  If there is OOB data to be written,
+ * this will ignore the computed ECC from the ECC controller.
+ *
+ * @param nand NAND device to write to.
+ * @param page Page to write.
+ * @param data Pointer to data being written.
+ * @param data_size Size of the data being written.
+ * @param oob Pointer to OOB data being written.
+ * @param oob_size Size of the OOB data.
+ * @return Success or failure of the page write.
+ */
+static int at91sam9_write_page(struct nand_device *nand, uint32_t page,
+		uint8_t *data, uint32_t data_size, uint8_t *oob, uint32_t oob_size)
+{
+	struct at91sam9_nand *info = nand->controller_priv;
+	struct target *target = info->target;
+	int retval;
+	uint8_t *oob_data = oob;
+	uint32_t parity, nparity;
+
+	retval = at91sam9_ecc_init(target, info);
+	if (ERROR_OK != retval) {
+		return retval;
+	}
+
+	retval = nand_page_command(nand, page, NAND_CMD_SEQIN, !data);
+	if (ERROR_OK != retval) {
+		return retval;
+	}
+
+	if (data) {
+		retval = nand_write_data_page(nand, data, data_size);
+		if (ERROR_OK != retval) {
+			LOG_ERROR("Unable to write data to NAND device");
+			return retval;
+		}
+	}
+
+	oob_data = at91sam9_oob_init(nand, oob, &oob_size);
+
+	if (!oob) {
+		// no OOB given, so read in the ECC parity from the ECC controller
+		target_read_u32(target, info->ecc + AT91C_ECCx_PR, &parity);
+		target_read_u32(target, info->ecc + AT91C_ECCx_NPR, &nparity);
+
+		oob_data[0] = (uint8_t) parity;
+		oob_data[1] = (uint8_t) (parity >> 8);
+		oob_data[2] = (uint8_t) nparity;
+		oob_data[3] = (uint8_t) (nparity >> 8);
+	}
+
+	retval = nand_write_data_page(nand, oob_data, oob_size);
+
+	if (!oob) {
+		free(oob_data);
+	}
+
+	if (ERROR_OK != retval) {
+		LOG_ERROR("Unable to write OOB data to NAND");
+		return retval;
+	}
+
+	retval = nand_write_finish(nand);
+
+	return retval;
+}
+
+/**
+ * Handle the initial NAND device command for AT91SAM9 controllers.  This
+ * initializes much of the controller information struct to be ready for future
+ * reads and writes.
+ */
+NAND_DEVICE_COMMAND_HANDLER(at91sam9_nand_device_command)
+{
+	struct target *target = NULL;
+	unsigned long chip = 0, ecc = 0;
+	struct at91sam9_nand *info = NULL;
+
+	LOG_DEBUG("AT91SAM9 NAND Device Command\n");
+
+	if (CMD_ARGC < 3 || CMD_ARGC > 4) {
+		LOG_ERROR("parameters: %s target chip_addr", CMD_ARGV[0]);
+		return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	target = get_target(CMD_ARGV[1]);
+	if (!target) {
+		LOG_ERROR("invalid target: %s", CMD_ARGV[1]);
+		return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	COMMAND_PARSE_NUMBER(ulong, CMD_ARGV[2], chip);
+	if (chip == 0) {
+		LOG_ERROR("invalid NAND chip address: %s", CMD_ARGV[2]);
+		return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	if (CMD_ARGC == 4) {
+		COMMAND_PARSE_NUMBER(ulong, CMD_ARGV[3], ecc);
+		if (ecc == 0) {
+			LOG_ERROR("invalid ECC controller address: %s", CMD_ARGV[3]);
+			return ERROR_NAND_OPERATION_FAILED;
+		}
+	}
+
+	info = calloc(1, sizeof(*info));
+	if (!info) {
+		LOG_ERROR("unable to allocate space for controller private data");
+		return ERROR_NAND_OPERATION_FAILED;
+	}
+
+	info->target = target;
+	info->data = chip;
+	info->cmd = chip | (1 << 22);
+	info->addr = chip | (1 << 21);
+	info->ecc = ecc;
+
+	nand->controller_priv = info;
+	info->io.target = target;
+	info->io.data = info->data;
+	info->io.op = ARM_NAND_NONE;
+
+	return ERROR_OK;
+}
+
+/**
+ * Handle the AT91SAM9 CLE command for specifying the address line to use for
+ * writing commands to a NAND device.
+ */
+COMMAND_HANDLER(handle_at91sam9_cle_command)
+{
+	struct nand_device *nand = NULL;
+	struct at91sam9_nand *info = NULL;
+	unsigned num, address_line;
+
+	if (CMD_ARGC != 2) {
+		command_print(CMD_CTX, "incorrect number of arguments for 'at91sam9 cle' command");
+		return ERROR_OK;
+	}
+
+	COMMAND_PARSE_NUMBER(uint, CMD_ARGV[0], num);
+	nand = get_nand_device_by_num(num);
+	if (!nand) {
+		command_print(CMD_CTX, "invalid nand device number: %s", CMD_ARGV[0]);
+		return ERROR_OK;
+	}
+
+	info = nand->controller_priv;
+
+	COMMAND_PARSE_NUMBER(uint, CMD_ARGV[1], address_line);
+	info->cmd = info->data | (1 << address_line);
+
+	return ERROR_OK;
+}
+
+/**
+ * Handle the AT91SAM9 ALE command for specifying the address line to use for
+ * writing addresses to the NAND device.
+ */
+COMMAND_HANDLER(handle_at91sam9_ale_command)
+{
+	struct nand_device *nand = NULL;
+	struct at91sam9_nand *info = NULL;
+	unsigned num, address_line;
+
+	if (CMD_ARGC != 2) {
+		return ERROR_COMMAND_SYNTAX_ERROR;
+	}
+
+	COMMAND_PARSE_NUMBER(uint, CMD_ARGV[0], num);
+	nand = get_nand_device_by_num(num);
+	if (!nand) {
+		command_print(CMD_CTX, "invalid nand device number: %s", CMD_ARGV[0]);
+		return ERROR_COMMAND_ARGUMENT_INVALID;
+	}
+
+	info = nand->controller_priv;
+
+	COMMAND_PARSE_NUMBER(uint, CMD_ARGV[1], address_line);
+	info->addr = info->data | (1 << address_line);
+
+	return ERROR_OK;
+}
+
+/**
+ * Handle the AT91SAM9 RDY/~BUSY command for specifying the pin that watches the
+ * RDY/~BUSY line from the NAND device.
+ */
+COMMAND_HANDLER(handle_at91sam9_rdy_busy_command)
+{
+	struct nand_device *nand = NULL;
+	struct at91sam9_nand *info = NULL;
+	unsigned num, base_pioc, pin_num;
+
+	if (CMD_ARGC != 3) {
+		return ERROR_COMMAND_SYNTAX_ERROR;
+	}
+
+	COMMAND_PARSE_NUMBER(uint, CMD_ARGV[0], num);
+	nand = get_nand_device_by_num(num);
+	if (!nand) {
+		command_print(CMD_CTX, "invalid nand device number: %s", CMD_ARGV[0]);
+		return ERROR_COMMAND_ARGUMENT_INVALID;
+	}
+
+	info = nand->controller_priv;
+
+	COMMAND_PARSE_NUMBER(uint, CMD_ARGV[1], base_pioc);
+	info->busy.pioc = base_pioc;
+
+	COMMAND_PARSE_NUMBER(uint, CMD_ARGV[2], pin_num);
+	info->busy.num = pin_num;
+
+	return ERROR_OK;
+}
+
+/**
+ * Handle the AT91SAM9 CE command for specifying the pin that is used to enable
+ * or disable the NAND device.
+ */
+COMMAND_HANDLER(handle_at91sam9_ce_command)
+{
+	struct nand_device *nand = NULL;
+	struct at91sam9_nand *info = NULL;
+	unsigned num, base_pioc, pin_num;
+
+	if (CMD_ARGC != 3) {
+		return ERROR_COMMAND_SYNTAX_ERROR;
+	}
+
+	COMMAND_PARSE_NUMBER(uint, CMD_ARGV[0], num);
+	nand = get_nand_device_by_num(num);
+	if (!nand) {
+		command_print(CMD_CTX, "invalid nand device number: %s", CMD_ARGV[0]);
+		return ERROR_COMMAND_ARGUMENT_INVALID;
+	}
+
+	info = nand->controller_priv;
+
+	COMMAND_PARSE_NUMBER(uint, CMD_ARGV[1], base_pioc);
+	info->ce.pioc = base_pioc;
+
+	COMMAND_PARSE_NUMBER(uint, CMD_ARGV[2], pin_num);
+	info->ce.num = pin_num;
+
+	return ERROR_OK;
+}
+
+static const struct command_registration at91sam9_sub_command_handlers[] = {
+	{
+		.name = "cle",
+		.handler = handle_at91sam9_cle_command,
+		.mode = COMMAND_CONFIG,
+		.help = "set command latch enable address line (default is 22)",
+		.usage = "<device_id> <address_line>",
+	},
+	{
+		.name = "ale",
+		.handler = handle_at91sam9_ale_command,
+		.mode = COMMAND_CONFIG,
+		.help = "set address latch enable address line (default is 21)",
+		.usage = "<device_id> <address_line>",
+	},
+	{
+		.name = "rdy_busy",
+		.handler = handle_at91sam9_rdy_busy_command,
+		.mode = COMMAND_CONFIG,
+		.help = "set the input pin connected to RDY/~BUSY signal (no default)",
+		.usage = "<device_id> <base_pioc> <pin_num>",
+	},
+	{
+		.name = "ce",
+		.handler = handle_at91sam9_ce_command,
+		.mode = COMMAND_CONFIG,
+		.help = "set the output pin connected to chip enable signal (no default)",
+		.usage = "<device_id> <base_pioc> <pin_num>",
+	},
+	COMMAND_REGISTRATION_DONE
+};
+
+static const struct command_registration at91sam9_command_handler[] = {
+	{
+		.name = "at91sam9",
+		.mode = COMMAND_ANY,
+		.help = "AT91SAM9 NAND flash controller commands",
+		.chain = at91sam9_sub_command_handlers,
+	},
+	COMMAND_REGISTRATION_DONE
+};
+
+/**
+ * Structure representing the AT91SAM9 NAND controller.
+ */
+struct nand_flash_controller at91sam9_nand_controller = {
+	.name = "at91sam9",
+	.nand_device_command = at91sam9_nand_device_command,
+	.commands = at91sam9_command_handler,
+	.init = at91sam9_init,
+	.command = at91sam9_command,
+	.reset = at91sam9_reset,
+	.address = at91sam9_address,
+	.read_data = at91sam9_read_data,
+	.write_data = at91sam9_write_data,
+	.nand_ready = at91sam9_nand_ready,
+	.read_block_data = at91sam9_read_block_data,
+	.write_block_data = at91sam9_write_block_data,
+	.read_page = at91sam9_read_page,
+	.write_page = at91sam9_write_page,
+};
diff --git a/src/flash/nand/driver.c b/src/flash/nand/driver.c
index 1ccc4f44..0e174b23 100644
--- a/src/flash/nand/driver.c
+++ b/src/flash/nand/driver.c
@@ -37,6 +37,7 @@ extern struct nand_flash_controller s3c2412_nand_controller;
 extern struct nand_flash_controller s3c2440_nand_controller;
 extern struct nand_flash_controller s3c2443_nand_controller;
 extern struct nand_flash_controller imx31_nand_flash_controller;
+extern struct nand_flash_controller at91sam9_nand_controller;
 
 /* extern struct nand_flash_controller boundary_scan_nand_controller; */
 
@@ -51,6 +52,7 @@ static struct nand_flash_controller *nand_flash_controllers[] =
 	&s3c2440_nand_controller,
 	&s3c2443_nand_controller,
 	&imx31_nand_flash_controller,
+	&at91sam9_nand_controller,
 /*	&boundary_scan_nand_controller, */
 	NULL
 };