mtd: nand: add tango NAND flash controller support

This driver supports the NAND Flash controller embedded in recent
Tango chips, such as SMP8758 and SMP8759.

Signed-off-by: Marc Gonzalez <[e-mail]>
Signed-off-by: Boris Brezillon <[e-mail]>

drivers/mtd/nand/Kconfig

···
 	  when the is NAND chip selected or released, but will save
 	  approximately 5mA of power when there is nothing happening.
 
+config MTD_NAND_TANGO
+	tristate "NAND Flash support for Tango chips"
+	depends on ARCH_TANGO || COMPILE_TEST
+	depends on HAS_DMA
+	help
+	  Enables the NAND Flash controller on Tango chips.
+
 config MTD_NAND_DISKONCHIP
 	tristate "DiskOnChip 2000, Millennium and Millennium Plus (NAND reimplementation)"
 	depends on HAS_IOMEM

drivers/mtd/nand/Makefile

···
 obj-$(CONFIG_MTD_NAND_AU1550)		+= au1550nd.o
 obj-$(CONFIG_MTD_NAND_BF5XX)		+= bf5xx_nand.o
 obj-$(CONFIG_MTD_NAND_S3C2410)		+= s3c2410.o
+obj-$(CONFIG_MTD_NAND_TANGO)		+= tango_nand.o
 obj-$(CONFIG_MTD_NAND_DAVINCI)		+= davinci_nand.o
 obj-$(CONFIG_MTD_NAND_DISKONCHIP)	+= diskonchip.o
 obj-$(CONFIG_MTD_NAND_DOCG4)		+= docg4.o

drivers/mtd/nand/tango_nand.c

···
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/clk.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/mtd/nand.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/platform_device.h>
+
+/* Offsets relative to chip->base */
+#define PBUS_CMD	0
+#define PBUS_ADDR	4
+#define PBUS_DATA	8
+
+/* Offsets relative to reg_base */
+#define NFC_STATUS	0x00
+#define NFC_FLASH_CMD	0x04
+#define NFC_DEVICE_CFG	0x08
+#define NFC_TIMING1	0x0c
+#define NFC_TIMING2	0x10
+#define NFC_XFER_CFG	0x14
+#define NFC_PKT_0_CFG	0x18
+#define NFC_PKT_N_CFG	0x1c
+#define NFC_BB_CFG	0x20
+#define NFC_ADDR_PAGE	0x24
+#define NFC_ADDR_OFFSET	0x28
+#define NFC_XFER_STATUS	0x2c
+
+/* NFC_STATUS values */
+#define CMD_READY	BIT(31)
+
+/* NFC_FLASH_CMD values */
+#define NFC_READ	1
+#define NFC_WRITE	2
+
+/* NFC_XFER_STATUS values */
+#define PAGE_IS_EMPTY	BIT(16)
+
+/* Offsets relative to mem_base */
+#define METADATA	0x000
+#define ERROR_REPORT	0x1c0
+
+/*
+ * Error reports are split in two bytes:
+ * byte 0 for the first packet in the page (PKT_0)
+ * byte 1 for other packets in the page (PKT_N, for N > 0)
+ * ERR_COUNT_PKT_N is the max error count over all but the first packet.
+ */
+#define DECODE_OK_PKT_0(v)	((v) & BIT(7))
+#define DECODE_OK_PKT_N(v)	((v) & BIT(15))
+#define ERR_COUNT_PKT_0(v)	(((v) >> 0) & 0x3f)
+#define ERR_COUNT_PKT_N(v)	(((v) >> 8) & 0x3f)
+
+/* Offsets relative to pbus_base */
+#define PBUS_CS_CTRL	0x83c
+#define PBUS_PAD_MODE	0x8f0
+
+/* PBUS_CS_CTRL values */
+#define PBUS_IORDY	BIT(31)
+
+/*
+ * PBUS_PAD_MODE values
+ * In raw mode, the driver communicates directly with the NAND chips.
+ * In NFC mode, the NAND Flash controller manages the communication.
+ * We use NFC mode for read and write; raw mode for everything else.
+ */
+#define MODE_RAW	0
+#define MODE_NFC	BIT(31)
+
+#define METADATA_SIZE	4
+#define BBM_SIZE	6
+#define FIELD_ORDER	15
+
+#define MAX_CS		4
+
+struct tango_nfc {
+	struct nand_hw_control hw;
+	void __iomem *reg_base;
+	void __iomem *mem_base;
+	void __iomem *pbus_base;
+	struct tango_chip *chips[MAX_CS];
+	struct dma_chan *chan;
+	int freq_kHz;
+};
+
+#define to_tango_nfc(ptr) container_of(ptr, struct tango_nfc, hw)
+
+struct tango_chip {
+	struct nand_chip nand_chip;
+	void __iomem *base;
+	u32 timing1;
+	u32 timing2;
+	u32 xfer_cfg;
+	u32 pkt_0_cfg;
+	u32 pkt_n_cfg;
+	u32 bb_cfg;
+};
+
+#define to_tango_chip(ptr) container_of(ptr, struct tango_chip, nand_chip)
+
+#define XFER_CFG(cs, page_count, steps, metadata_size)	\
+	((cs) << 24 | (page_count) << 16 | (steps) << 8 | (metadata_size))
+
+#define PKT_CFG(size, strength) ((size) << 16 | (strength))
+
+#define BB_CFG(bb_offset, bb_size) ((bb_offset) << 16 | (bb_size))
+
+#define TIMING(t0, t1, t2, t3) ((t0) << 24 | (t1) << 16 | (t2) << 8 | (t3))
+
+static void tango_cmd_ctrl(struct mtd_info *mtd, int dat, unsigned int ctrl)
+{
+	struct tango_chip *tchip = to_tango_chip(mtd_to_nand(mtd));
+
+	if (ctrl & NAND_CLE)
+		writeb_relaxed(dat, tchip->base + PBUS_CMD);
+
+	if (ctrl & NAND_ALE)
+		writeb_relaxed(dat, tchip->base + PBUS_ADDR);
+}
+
+static int tango_dev_ready(struct mtd_info *mtd)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct tango_nfc *nfc = to_tango_nfc(chip->controller);
+
+	return readl_relaxed(nfc->pbus_base + PBUS_CS_CTRL) & PBUS_IORDY;
+}
+
+static u8 tango_read_byte(struct mtd_info *mtd)
+{
+	struct tango_chip *tchip = to_tango_chip(mtd_to_nand(mtd));
+
+	return readb_relaxed(tchip->base + PBUS_DATA);
+}
+
+static void tango_read_buf(struct mtd_info *mtd, u8 *buf, int len)
+{
+	struct tango_chip *tchip = to_tango_chip(mtd_to_nand(mtd));
+
+	ioread8_rep(tchip->base + PBUS_DATA, buf, len);
+}
+
+static void tango_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
+{
+	struct tango_chip *tchip = to_tango_chip(mtd_to_nand(mtd));
+
+	iowrite8_rep(tchip->base + PBUS_DATA, buf, len);
+}
+
+static void tango_select_chip(struct mtd_info *mtd, int idx)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct tango_nfc *nfc = to_tango_nfc(chip->controller);
+	struct tango_chip *tchip = to_tango_chip(chip);
+
+	if (idx < 0)
+		return; /* No "chip unselect" function */
+
+	writel_relaxed(tchip->timing1, nfc->reg_base + NFC_TIMING1);
+	writel_relaxed(tchip->timing2, nfc->reg_base + NFC_TIMING2);
+	writel_relaxed(tchip->xfer_cfg, nfc->reg_base + NFC_XFER_CFG);
+	writel_relaxed(tchip->pkt_0_cfg, nfc->reg_base + NFC_PKT_0_CFG);
+	writel_relaxed(tchip->pkt_n_cfg, nfc->reg_base + NFC_PKT_N_CFG);
+	writel_relaxed(tchip->bb_cfg, nfc->reg_base + NFC_BB_CFG);
+}
+
+/*
+ * The controller does not check for bitflips in erased pages,
+ * therefore software must check instead.
+ */
+static int check_erased_page(struct nand_chip *chip, u8 *buf)
+{
+	u8 *meta = chip->oob_poi + BBM_SIZE;
+	u8 *ecc = chip->oob_poi + BBM_SIZE + METADATA_SIZE;
+	const int ecc_size = chip->ecc.bytes;
+	const int pkt_size = chip->ecc.size;
+	int i, res, meta_len, bitflips = 0;
+
+	for (i = 0; i < chip->ecc.steps; ++i) {
+		meta_len = i ? 0 : METADATA_SIZE;
+		res = nand_check_erased_ecc_chunk(buf, pkt_size, ecc, ecc_size,
+						  meta, meta_len,
+						  chip->ecc.strength);
+		if (res < 0)
+			chip->mtd.ecc_stats.failed++;
+
+		bitflips = max(res, bitflips);
+		buf += pkt_size;
+		ecc += ecc_size;
+	}
+
+	return bitflips;
+}
+
+static int decode_error_report(struct tango_nfc *nfc)
+{
+	u32 status, res;
+
+	status = readl_relaxed(nfc->reg_base + NFC_XFER_STATUS);
+	if (status & PAGE_IS_EMPTY)
+		return 0;
+
+	res = readl_relaxed(nfc->mem_base + ERROR_REPORT);
+
+	if (DECODE_OK_PKT_0(res) && DECODE_OK_PKT_N(res))
+		return max(ERR_COUNT_PKT_0(res), ERR_COUNT_PKT_N(res));
+
+	return -EBADMSG;
+}
+
+static void tango_dma_callback(void *arg)
+{
+	complete(arg);
+}
+
+static int do_dma(struct tango_nfc *nfc, int dir, int cmd, const void *buf,
+		  int len, int page)
+{
+	void __iomem *addr = nfc->reg_base + NFC_STATUS;
+	struct dma_chan *chan = nfc->chan;
+	struct dma_async_tx_descriptor *desc;
+	struct scatterlist sg;
+	struct completion tx_done;
+	int err = -EIO;
+	u32 res, val;
+
+	sg_init_one(&sg, buf, len);
+	if (dma_map_sg(chan->device->dev, &sg, 1, dir) != 1)
+		return -EIO;
+
+	desc = dmaengine_prep_slave_sg(chan, &sg, 1, dir, DMA_PREP_INTERRUPT);
+	if (!desc)
+		goto dma_unmap;
+
+	desc->callback = tango_dma_callback;
+	desc->callback_param = &tx_done;
+	init_completion(&tx_done);
+
+	writel_relaxed(MODE_NFC, nfc->pbus_base + PBUS_PAD_MODE);
+
+	writel_relaxed(page, nfc->reg_base + NFC_ADDR_PAGE);
+	writel_relaxed(0, nfc->reg_base + NFC_ADDR_OFFSET);
+	writel_relaxed(cmd, nfc->reg_base + NFC_FLASH_CMD);
+
+	dmaengine_submit(desc);
+	dma_async_issue_pending(chan);
+
+	res = wait_for_completion_timeout(&tx_done, HZ);
+	if (res > 0)
+		err = readl_poll_timeout(addr, val, val & CMD_READY, 0, 1000);
+
+	writel_relaxed(MODE_RAW, nfc->pbus_base + PBUS_PAD_MODE);
+
+dma_unmap:
+	dma_unmap_sg(chan->device->dev, &sg, 1, dir);
+
+	return err;
+}
+
+static int tango_read_page(struct mtd_info *mtd, struct nand_chip *chip,
+			   u8 *buf, int oob_required, int page)
+{
+	struct tango_nfc *nfc = to_tango_nfc(chip->controller);
+	int err, res, len = mtd->writesize;
+
+	if (oob_required)
+		chip->ecc.read_oob(mtd, chip, page);
+
+	err = do_dma(nfc, DMA_FROM_DEVICE, NFC_READ, buf, len, page);
+	if (err)
+		return err;
+
+	res = decode_error_report(nfc);
+	if (res < 0) {
+		chip->ecc.read_oob_raw(mtd, chip, page);
+		res = check_erased_page(chip, buf);
+	}
+
+	return res;
+}
+
+static int tango_write_page(struct mtd_info *mtd, struct nand_chip *chip,
+			    const u8 *buf, int oob_required, int page)
+{
+	struct tango_nfc *nfc = to_tango_nfc(chip->controller);
+	int err, len = mtd->writesize;
+
+	/* Calling tango_write_oob() would send PAGEPROG twice */
+	if (oob_required)
+		return -ENOTSUPP;
+
+	writel_relaxed(0xffffffff, nfc->mem_base + METADATA);
+	err = do_dma(nfc, DMA_TO_DEVICE, NFC_WRITE, buf, len, page);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static void aux_read(struct nand_chip *chip, u8 **buf, int len, int *pos)
+{
+	*pos += len;
+
+	if (!*buf) {
+		/* skip over "len" bytes */
+		chip->cmdfunc(&chip->mtd, NAND_CMD_RNDOUT, *pos, -1);
+	} else {
+		tango_read_buf(&chip->mtd, *buf, len);
+		*buf += len;
+	}
+}
+
+static void aux_write(struct nand_chip *chip, const u8 **buf, int len, int *pos)
+{
+	*pos += len;
+
+	if (!*buf) {
+		/* skip over "len" bytes */
+		chip->cmdfunc(&chip->mtd, NAND_CMD_SEQIN, *pos, -1);
+	} else {
+		tango_write_buf(&chip->mtd, *buf, len);
+		*buf += len;
+	}
+}
+
+/*
+ * Physical page layout (not drawn to scale)
+ *
+ * NB: Bad Block Marker area splits PKT_N in two (N1, N2).
+ *
+ * +---+-----------------+-------+-----+-----------+-----+----+-------+
+ * | M |      PKT_0      | ECC_0 | ... |     N1    | BBM | N2 | ECC_N |
+ * +---+-----------------+-------+-----+-----------+-----+----+-------+
+ *
+ * Logical page layout:
+ *
+ *       +-----+---+-------+-----+-------+
+ * oob = | BBM | M | ECC_0 | ... | ECC_N |
+ *       +-----+---+-------+-----+-------+
+ *
+ *       +-----------------+-----+-----------------+
+ * buf = |      PKT_0      | ... |      PKT_N      |
+ *       +-----------------+-----+-----------------+
+ */
+static int raw_read(struct nand_chip *chip, u8 *buf, u8 *oob)
+{
+	u8 *oob_orig = oob;
+	const int page_size = chip->mtd.writesize;
+	const int ecc_size = chip->ecc.bytes;
+	const int pkt_size = chip->ecc.size;
+	int pos = 0; /* position within physical page */
+	int rem = page_size; /* bytes remaining until BBM area */
+
+	if (oob)
+		oob += BBM_SIZE;
+
+	aux_read(chip, &oob, METADATA_SIZE, &pos);
+
+	while (rem > pkt_size) {
+		aux_read(chip, &buf, pkt_size, &pos);
+		aux_read(chip, &oob, ecc_size, &pos);
+		rem = page_size - pos;
+	}
+
+	aux_read(chip, &buf, rem, &pos);
+	aux_read(chip, &oob_orig, BBM_SIZE, &pos);
+	aux_read(chip, &buf, pkt_size - rem, &pos);
+	aux_read(chip, &oob, ecc_size, &pos);
+
+	return 0;
+}
+
+static int raw_write(struct nand_chip *chip, const u8 *buf, const u8 *oob)
+{
+	const u8 *oob_orig = oob;
+	const int page_size = chip->mtd.writesize;
+	const int ecc_size = chip->ecc.bytes;
+	const int pkt_size = chip->ecc.size;
+	int pos = 0; /* position within physical page */
+	int rem = page_size; /* bytes remaining until BBM area */
+
+	if (oob)
+		oob += BBM_SIZE;
+
+	aux_write(chip, &oob, METADATA_SIZE, &pos);
+
+	while (rem > pkt_size) {
+		aux_write(chip, &buf, pkt_size, &pos);
+		aux_write(chip, &oob, ecc_size, &pos);
+		rem = page_size - pos;
+	}
+
+	aux_write(chip, &buf, rem, &pos);
+	aux_write(chip, &oob_orig, BBM_SIZE, &pos);
+	aux_write(chip, &buf, pkt_size - rem, &pos);
+	aux_write(chip, &oob, ecc_size, &pos);
+
+	return 0;
+}
+
+static int tango_read_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
+			       u8 *buf, int oob_required, int page)
+{
+	return raw_read(chip, buf, chip->oob_poi);
+}
+
+static int tango_write_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
+				const u8 *buf, int oob_required, int page)
+{
+	return raw_write(chip, buf, chip->oob_poi);
+}
+
+static int tango_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
+			  int page)
+{
+	chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
+	return raw_read(chip, NULL, chip->oob_poi);
+}
+
+static int tango_write_oob(struct mtd_info *mtd, struct nand_chip *chip,
+			   int page)
+{
+	chip->cmdfunc(mtd, NAND_CMD_SEQIN, 0, page);
+	raw_write(chip, NULL, chip->oob_poi);
+	chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);
+	chip->waitfunc(mtd, chip);
+	return 0;
+}
+
+static int oob_ecc(struct mtd_info *mtd, int idx, struct mtd_oob_region *res)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+
+	if (idx >= ecc->steps)
+		return -ERANGE;
+
+	res->offset = BBM_SIZE + METADATA_SIZE + ecc->bytes * idx;
+	res->length = ecc->bytes;
+
+	return 0;
+}
+
+static int oob_free(struct mtd_info *mtd, int idx, struct mtd_oob_region *res)
+{
+	return -ERANGE; /* no free space in spare area */
+}
+
+static const struct mtd_ooblayout_ops tango_nand_ooblayout_ops = {
+	.ecc	= oob_ecc,
+	.free	= oob_free,
+};
+
+static u32 to_ticks(int kHz, int ps)
+{
+	return DIV_ROUND_UP_ULL((u64)kHz * ps, NSEC_PER_SEC);
+}
+
+static int tango_set_timings(struct mtd_info *mtd,
+			     const struct nand_data_interface *conf,
+			     bool check_only)
+{
+	const struct nand_sdr_timings *sdr = nand_get_sdr_timings(conf);
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct tango_nfc *nfc = to_tango_nfc(chip->controller);
+	struct tango_chip *tchip = to_tango_chip(chip);
+	u32 Trdy, Textw, Twc, Twpw, Tacc, Thold, Trpw, Textr;
+	int kHz = nfc->freq_kHz;
+
+	if (IS_ERR(sdr))
+		return PTR_ERR(sdr);
+
+	if (check_only)
+		return 0;
+
+	Trdy = to_ticks(kHz, sdr->tCEA_max - sdr->tREA_max);
+	Textw = to_ticks(kHz, sdr->tWB_max);
+	Twc = to_ticks(kHz, sdr->tWC_min);
+	Twpw = to_ticks(kHz, sdr->tWC_min - sdr->tWP_min);
+
+	Tacc = to_ticks(kHz, sdr->tREA_max);
+	Thold = to_ticks(kHz, sdr->tREH_min);
+	Trpw = to_ticks(kHz, sdr->tRC_min - sdr->tREH_min);
+	Textr = to_ticks(kHz, sdr->tRHZ_max);
+
+	tchip->timing1 = TIMING(Trdy, Textw, Twc, Twpw);
+	tchip->timing2 = TIMING(Tacc, Thold, Trpw, Textr);
+
+	return 0;
+}
+
+static int chip_init(struct device *dev, struct device_node *np)
+{
+	u32 cs;
+	int err, res;
+	struct mtd_info *mtd;
+	struct nand_chip *chip;
+	struct tango_chip *tchip;
+	struct nand_ecc_ctrl *ecc;
+	struct tango_nfc *nfc = dev_get_drvdata(dev);
+
+	tchip = devm_kzalloc(dev, sizeof(*tchip), GFP_KERNEL);
+	if (!tchip)
+		return -ENOMEM;
+
+	res = of_property_count_u32_elems(np, "reg");
+	if (res < 0)
+		return res;
+
+	if (res != 1)
+		return -ENOTSUPP; /* Multi-CS chips are not supported */
+
+	err = of_property_read_u32_index(np, "reg", 0, &cs);
+	if (err)
+		return err;
+
+	if (cs >= MAX_CS)
+		return -EINVAL;
+
+	chip = &tchip->nand_chip;
+	ecc = &chip->ecc;
+	mtd = &chip->mtd;
+
+	chip->read_byte = tango_read_byte;
+	chip->write_buf = tango_write_buf;
+	chip->read_buf = tango_read_buf;
+	chip->select_chip = tango_select_chip;
+	chip->cmd_ctrl = tango_cmd_ctrl;
+	chip->dev_ready = tango_dev_ready;
+	chip->setup_data_interface = tango_set_timings;
+	chip->options = NAND_USE_BOUNCE_BUFFER |
+			NAND_NO_SUBPAGE_WRITE |
+			NAND_WAIT_TCCS;
+	chip->controller = &nfc->hw;
+	tchip->base = nfc->pbus_base + (cs * 256);
+
+	nand_set_flash_node(chip, np);
+	mtd_set_ooblayout(mtd, &tango_nand_ooblayout_ops);
+	mtd->dev.parent = dev;
+
+	err = nand_scan_ident(mtd, 1, NULL);
+	if (err)
+		return err;
+
+	ecc->mode = NAND_ECC_HW;
+	ecc->algo = NAND_ECC_BCH;
+	ecc->bytes = DIV_ROUND_UP(ecc->strength * FIELD_ORDER, BITS_PER_BYTE);
+
+	ecc->read_page_raw = tango_read_page_raw;
+	ecc->write_page_raw = tango_write_page_raw;
+	ecc->read_page = tango_read_page;
+	ecc->write_page = tango_write_page;
+	ecc->read_oob = tango_read_oob;
+	ecc->write_oob = tango_write_oob;
+
+	err = nand_scan_tail(mtd);
+	if (err)
+		return err;
+
+	tchip->xfer_cfg = XFER_CFG(cs, 1, ecc->steps, METADATA_SIZE);
+	tchip->pkt_0_cfg = PKT_CFG(ecc->size + METADATA_SIZE, ecc->strength);
+	tchip->pkt_n_cfg = PKT_CFG(ecc->size, ecc->strength);
+	tchip->bb_cfg = BB_CFG(mtd->writesize, BBM_SIZE);
+
+	err = mtd_device_register(mtd, NULL, 0);
+	if (err)
+		return err;
+
+	nfc->chips[cs] = tchip;
+
+	return 0;
+}
+
+static int tango_nand_remove(struct platform_device *pdev)
+{
+	int cs;
+	struct tango_nfc *nfc = platform_get_drvdata(pdev);
+
+	dma_release_channel(nfc->chan);
+
+	for (cs = 0; cs < MAX_CS; ++cs) {
+		if (nfc->chips[cs])
+			nand_release(&nfc->chips[cs]->nand_chip.mtd);
+	}
+
+	return 0;
+}
+
+static int tango_nand_probe(struct platform_device *pdev)
+{
+	int err;
+	struct clk *clk;
+	struct resource *res;
+	struct tango_nfc *nfc;
+	struct device_node *np;
+
+	nfc = devm_kzalloc(&pdev->dev, sizeof(*nfc), GFP_KERNEL);
+	if (!nfc)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	nfc->reg_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(nfc->reg_base))
+		return PTR_ERR(nfc->reg_base);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	nfc->mem_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(nfc->mem_base))
+		return PTR_ERR(nfc->mem_base);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
+	nfc->pbus_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(nfc->pbus_base))
+		return PTR_ERR(nfc->pbus_base);
+
+	clk = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	nfc->chan = dma_request_chan(&pdev->dev, "nfc_sbox");
+	if (IS_ERR(nfc->chan))
+		return PTR_ERR(nfc->chan);
+
+	platform_set_drvdata(pdev, nfc);
+	nand_hw_control_init(&nfc->hw);
+	nfc->freq_kHz = clk_get_rate(clk) / 1000;
+
+	for_each_child_of_node(pdev->dev.of_node, np) {
+		err = chip_init(&pdev->dev, np);
+		if (err) {
+			tango_nand_remove(pdev);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static const struct of_device_id tango_nand_ids[] = {
+	{ .compatible = "sigma,smp8758-nand" },
+	{ /* sentinel */ }
+};
+
+static struct platform_driver tango_nand_driver = {
+	.probe	= tango_nand_probe,
+	.remove	= tango_nand_remove,
+	.driver	= {
+		.name		= "tango-nand",
+		.of_match_table	= tango_nand_ids,
+	},
+};
+
+module_platform_driver(tango_nand_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Sigma Designs");
+MODULE_DESCRIPTION("Tango4 NAND Flash controller driver");