[PATCH] davinci_nand: add support for the NAND controller

[Jan Luebbe <jluebbe@debian.org>]

This driver is based on the Linux driver (v4.0).

Signed-off-by: Jan Luebbe <jluebbe@debian.org>
---
 drivers/mtd/nand/Kconfig        |   7 +
 drivers/mtd/nand/Makefile       |   1 +
 drivers/mtd/nand/davinci_nand.c | 866 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 874 insertions(+)
 create mode 100644 drivers/mtd/nand/davinci_nand.c

diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index a75540b..41a3e31 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -140,4 +140,11 @@ config MTD_NAND_NOMADIK
 	help
 	  Driver for the NAND flash controller on the Nomadik, with ECC.
 
+config MTD_NAND_DAVINCI
+	tristate "Support NAND on DaVinci"
+	depends on ARCH_DAVINCI
+	help
+	  Enable the driver for NAND flash chips on Texas Instruments
+	  DaVinci processors.
+
 endif
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index a0b3198..b8644b2 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_NAND)			+= nand_base.o nand-bb.o
 obj-$(CONFIG_NAND_BBT)			+= nand_bbt.o
 
 obj-$(CONFIG_MTD_NAND_NOMADIK)		+= nomadik_nand.o
+obj-$(CONFIG_MTD_NAND_DAVINCI)		+= davinci_nand.o
 obj-$(CONFIG_NAND_IMX)			+= nand_imx.o
 obj-$(CONFIG_NAND_IMX_BBM)		+= nand_imx_bbm.o
 obj-$(CONFIG_NAND_OMAP_GPMC)		+= nand_omap_gpmc.o nand_omap_bch_decoder.o
diff --git a/drivers/mtd/nand/davinci_nand.c b/drivers/mtd/nand/davinci_nand.c
new file mode 100644
index 0000000..4b14b6c
--- /dev/null
+++ b/drivers/mtd/nand/davinci_nand.c
@@ -0,0 +1,866 @@
+/*
+ * davinci_nand.c - NAND Flash Driver for DaVinci family chips
+ *
+ * Copyright © 2006 Texas Instruments.
+ *
+ * Port to 2.6.23 Copyright © 2008 by:
+ *   Sander Huijsen <Shuijsen@optelecom-nkf.com>
+ *   Troy Kisky <troy.kisky@boundarydevices.com>
+ *   Dirk Behme <Dirk.Behme@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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+//#define DEBUG
+
+#include <common.h>
+#include <io.h>
+#include <malloc.h>
+#include <driver.h>
+#include <init.h>
+#include <clock.h>
+
+#include <of.h>
+#include <of_mtd.h>
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/mtd/nand.h>
+
+#define NANDFCR_OFFSET		0x60
+#define NANDFSR_OFFSET		0x64
+#define NANDF1ECC_OFFSET	0x70
+
+/* 4-bit ECC syndrome registers */
+#define NAND_4BIT_ECC_LOAD_OFFSET	0xbc
+#define NAND_4BIT_ECC1_OFFSET		0xc0
+#define NAND_4BIT_ECC2_OFFSET		0xc4
+#define NAND_4BIT_ECC3_OFFSET		0xc8
+#define NAND_4BIT_ECC4_OFFSET		0xcc
+#define NAND_ERR_ADD1_OFFSET		0xd0
+#define NAND_ERR_ADD2_OFFSET		0xd4
+#define NAND_ERR_ERRVAL1_OFFSET		0xd8
+#define NAND_ERR_ERRVAL2_OFFSET		0xdc
+
+/* NOTE:  boards don't need to use these address bits
+ * for ALE/CLE unless they support booting from NAND.
+ * They're used unless platform data overrides them.
+ */
+#define	MASK_ALE		0x08
+#define	MASK_CLE		0x10
+
+struct davinci_nand_pdata {		/* platform_data */
+	uint32_t		chipsel;
+
+	uint32_t		mask_ale;
+	uint32_t		mask_cle;
+
+	/* for packages using two chipselects */
+	uint32_t		mask_chipsel;
+
+	/* board's default static partition info */
+	struct mtd_partition	*parts;
+	unsigned		nr_parts;
+
+	/* none  == NAND_ECC_NONE (strongly *not* advised!!)
+	 * soft  == NAND_ECC_SOFT
+	 * else  == NAND_ECC_HW, according to ecc_bits
+	 *
+	 * All DaVinci-family chips support 1-bit hardware ECC.
+	 * Newer ones also support 4-bit ECC, but are awkward
+	 * using it with large page chips.
+	 */
+	nand_ecc_modes_t	ecc_mode;
+	u8			ecc_bits;
+
+	/* e.g. NAND_BUSWIDTH_16 */
+	unsigned		options;
+	/* e.g. NAND_BBT_USE_FLASH */
+	unsigned		bbt_options;
+
+	/* Main and mirror bbt descriptor overrides */
+	struct nand_bbt_descr	*bbt_td;
+	struct nand_bbt_descr	*bbt_md;
+
+	/* Access timings */
+	//struct davinci_aemif_timing	*timing;
+};
+
+#define NRCSR_OFFSET            0x00                                             
+#define AWCCR_OFFSET            0x04                                             
+#define A1CR_OFFSET             0x10                                             
+                                                                                 
+#define ACR_ASIZE_MASK          0x3                                              
+#define ACR_EW_MASK             BIT(30)                                          
+#define ACR_SS_MASK             BIT(31)                                          
+
+/*
+ * This is a device driver for the NAND flash controller found on the
+ * various DaVinci family chips.  It handles up to four SoC chipselects,
+ * and some flavors of secondary chipselect (e.g. based on A12) as used
+ * with multichip packages.
+ *
+ * The 1-bit ECC hardware is supported, as well as the newer 4-bit ECC
+ * available on chips like the DM355 and OMAP-L137 and needed with the
+ * more error-prone MLC NAND chips.
+ *
+ * This driver assumes EM_WAIT connects all the NAND devices' RDY/nBUSY
+ * outputs in a "wire-AND" configuration, with no per-chip signals.
+ */
+struct davinci_nand_info {
+	struct mtd_info		mtd;
+	struct nand_chip	chip;
+	struct nand_ecclayout	ecclayout;
+
+	struct device_d		*dev;
+	struct clk		*clk;
+
+	bool			is_readmode;
+
+	void __iomem		*base;
+	void __iomem		*vaddr;
+
+	uint32_t		ioaddr;
+	uint32_t		current_cs;
+
+	uint32_t		mask_chipsel;
+	uint32_t		mask_ale;
+	uint32_t		mask_cle;
+
+	uint32_t		core_chipsel;
+
+	//struct davinci_aemif_timing	*timing;
+};
+
+static bool ecc4_busy;
+
+#define to_davinci_nand(m) container_of(m, struct davinci_nand_info, mtd)
+
+
+static inline unsigned int davinci_nand_readl(struct davinci_nand_info *info,
+		int offset)
+{
+	return __raw_readl(info->base + offset);
+}
+
+static inline void davinci_nand_writel(struct davinci_nand_info *info,
+		int offset, unsigned long value)
+{
+	__raw_writel(value, info->base + offset);
+}
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * Access to hardware control lines:  ALE, CLE, secondary chipselect.
+ */
+
+static void nand_davinci_hwcontrol(struct mtd_info *mtd, int cmd,
+				   unsigned int ctrl)
+{
+	struct davinci_nand_info	*info = to_davinci_nand(mtd);
+	uint32_t			addr = info->current_cs;
+	struct nand_chip		*nand = mtd->priv;
+
+	/* Did the control lines change? */
+	if (ctrl & NAND_CTRL_CHANGE) {
+		if ((ctrl & NAND_CTRL_CLE) == NAND_CTRL_CLE)
+			addr |= info->mask_cle;
+		else if ((ctrl & NAND_CTRL_ALE) == NAND_CTRL_ALE)
+			addr |= info->mask_ale;
+
+		nand->IO_ADDR_W = (void __iomem __force *)addr;
+	}
+
+	if (cmd != NAND_CMD_NONE)
+		iowrite8(cmd, nand->IO_ADDR_W);
+}
+
+static void nand_davinci_select_chip(struct mtd_info *mtd, int chip)
+{
+	struct davinci_nand_info	*info = to_davinci_nand(mtd);
+	uint32_t			addr = info->ioaddr;
+
+	/* maybe kick in a second chipselect */
+	if (chip > 0)
+		addr |= info->mask_chipsel;
+	info->current_cs = addr;
+
+	info->chip.IO_ADDR_W = (void __iomem __force *)addr;
+	info->chip.IO_ADDR_R = info->chip.IO_ADDR_W;
+}
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * 1-bit hardware ECC ... context maintained for each core chipselect
+ */
+
+static inline uint32_t nand_davinci_readecc_1bit(struct mtd_info *mtd)
+{
+	struct davinci_nand_info *info = to_davinci_nand(mtd);
+
+	dev_dbg(info->dev, "%s\n", __func__);
+
+	return davinci_nand_readl(info, NANDF1ECC_OFFSET
+			+ 4 * info->core_chipsel);
+}
+
+static void nand_davinci_hwctl_1bit(struct mtd_info *mtd, int mode)
+{
+	struct davinci_nand_info *info = to_davinci_nand(mtd);
+	uint32_t nandcfr;
+
+	dev_dbg(info->dev, "%s\n", __func__);
+
+	/* Reset ECC hardware */
+	nand_davinci_readecc_1bit(mtd);
+
+	/* Restart ECC hardware */
+	nandcfr = davinci_nand_readl(info, NANDFCR_OFFSET);
+	nandcfr |= BIT(8 + info->core_chipsel);
+	davinci_nand_writel(info, NANDFCR_OFFSET, nandcfr);
+}
+
+/*
+ * Read hardware ECC value and pack into three bytes
+ */
+static int nand_davinci_calculate_1bit(struct mtd_info *mtd,
+				      const u_char *dat, u_char *ecc_code)
+{
+	struct davinci_nand_info *info = to_davinci_nand(mtd);
+	unsigned int ecc_val = nand_davinci_readecc_1bit(mtd);
+	unsigned int ecc24 = (ecc_val & 0x0fff) | ((ecc_val & 0x0fff0000) >> 4);
+
+	dev_dbg(info->dev, "%s\n", __func__);
+
+	/* invert so that erased block ecc is correct */
+	ecc24 = ~ecc24;
+	ecc_code[0] = (u_char)(ecc24);
+	ecc_code[1] = (u_char)(ecc24 >> 8);
+	ecc_code[2] = (u_char)(ecc24 >> 16);
+
+	return 0;
+}
+
+static int nand_davinci_correct_1bit(struct mtd_info *mtd, u_char *dat,
+				     u_char *read_ecc, u_char *calc_ecc)
+{
+	struct davinci_nand_info *info = to_davinci_nand(mtd);
+	struct nand_chip *chip = mtd->priv;
+	uint32_t eccNand = read_ecc[0] | (read_ecc[1] << 8) |
+					  (read_ecc[2] << 16);
+	uint32_t eccCalc = calc_ecc[0] | (calc_ecc[1] << 8) |
+					  (calc_ecc[2] << 16);
+	uint32_t diff = eccCalc ^ eccNand;
+
+	dev_dbg(info->dev, "%s nand=0x%x calc=0x%x\n", __func__, eccNand, eccCalc);
+
+	if (diff) {
+		if ((((diff >> 12) ^ diff) & 0xfff) == 0xfff) {
+			/* Correctable error */
+			if ((diff >> (12 + 3)) < chip->ecc.size) {
+				dat[diff >> (12 + 3)] ^= BIT((diff >> 12) & 7);
+				return 1;
+			} else {
+				return -1;
+			}
+		} else if (!(diff & (diff - 1))) {
+			/* Single bit ECC error in the ECC itself,
+			 * nothing to fix */
+			return 1;
+		} else {
+			/* Uncorrectable error */
+			return -1;
+		}
+
+	}
+	return 0;
+}
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * 4-bit hardware ECC ... context maintained over entire AEMIF
+ *
+ * This is a syndrome engine, but we avoid NAND_ECC_HW_SYNDROME
+ * since that forces use of a problematic "infix OOB" layout.
+ * Among other things, it trashes manufacturer bad block markers.
+ * Also, and specific to this hardware, it ECC-protects the "prepad"
+ * in the OOB ... while having ECC protection for parts of OOB would
+ * seem useful, the current MTD stack sometimes wants to update the
+ * OOB without recomputing ECC.
+ */
+
+static void nand_davinci_hwctl_4bit(struct mtd_info *mtd, int mode)
+{
+	struct davinci_nand_info *info = to_davinci_nand(mtd);
+	u32 val;
+
+	/* Start 4-bit ECC calculation for read/write */
+	val = davinci_nand_readl(info, NANDFCR_OFFSET);
+	val &= ~(0x03 << 4);
+	val |= (info->core_chipsel << 4) | BIT(12);
+	davinci_nand_writel(info, NANDFCR_OFFSET, val);
+
+	info->is_readmode = (mode == NAND_ECC_READ);
+}
+
+/* Read raw ECC code after writing to NAND. */
+static void
+nand_davinci_readecc_4bit(struct davinci_nand_info *info, u32 code[4])
+{
+	const u32 mask = 0x03ff03ff;
+
+	code[0] = davinci_nand_readl(info, NAND_4BIT_ECC1_OFFSET) & mask;
+	code[1] = davinci_nand_readl(info, NAND_4BIT_ECC2_OFFSET) & mask;
+	code[2] = davinci_nand_readl(info, NAND_4BIT_ECC3_OFFSET) & mask;
+	code[3] = davinci_nand_readl(info, NAND_4BIT_ECC4_OFFSET) & mask;
+}
+
+/* Terminate read ECC; or return ECC (as bytes) of data written to NAND. */
+static int nand_davinci_calculate_4bit(struct mtd_info *mtd,
+		const u_char *dat, u_char *ecc_code)
+{
+	struct davinci_nand_info *info = to_davinci_nand(mtd);
+	u32 raw_ecc[4], *p;
+	unsigned i;
+
+	/* After a read, terminate ECC calculation by a dummy read
+	 * of some 4-bit ECC register.  ECC covers everything that
+	 * was read; correct() just uses the hardware state, so
+	 * ecc_code is not needed.
+	 */
+	if (info->is_readmode) {
+		davinci_nand_readl(info, NAND_4BIT_ECC1_OFFSET);
+		return 0;
+	}
+
+	/* Pack eight raw 10-bit ecc values into ten bytes, making
+	 * two passes which each convert four values (in upper and
+	 * lower halves of two 32-bit words) into five bytes.  The
+	 * ROM boot loader uses this same packing scheme.
+	 */
+	nand_davinci_readecc_4bit(info, raw_ecc);
+	for (i = 0, p = raw_ecc; i < 2; i++, p += 2) {
+		*ecc_code++ =   p[0]        & 0xff;
+		*ecc_code++ = ((p[0] >>  8) & 0x03) | ((p[0] >> 14) & 0xfc);
+		*ecc_code++ = ((p[0] >> 22) & 0x0f) | ((p[1] <<  4) & 0xf0);
+		*ecc_code++ = ((p[1] >>  4) & 0x3f) | ((p[1] >> 10) & 0xc0);
+		*ecc_code++ =  (p[1] >> 18) & 0xff;
+	}
+
+	return 0;
+}
+
+/* Correct up to 4 bits in data we just read, using state left in the
+ * hardware plus the ecc_code computed when it was first written.
+ */
+static int nand_davinci_correct_4bit(struct mtd_info *mtd,
+		u_char *data, u_char *ecc_code, u_char *null)
+{
+	int i;
+	struct davinci_nand_info *info = to_davinci_nand(mtd);
+	unsigned short ecc10[8];
+	unsigned short *ecc16;
+	u32 syndrome[4];
+	unsigned num_errors, corrected;
+
+	/* All bytes 0xff?  It's an erased page; ignore its ECC. */
+	for (i = 0; i < 10; i++) {
+		if (ecc_code[i] != 0xff)
+			goto compare;
+	}
+	return 0;
+
+compare:
+	/* Unpack ten bytes into eight 10 bit values.  We know we're
+	 * little-endian, and use type punning for less shifting/masking.
+	 */
+	if (WARN_ON(0x01 & (unsigned) ecc_code))
+		return -EINVAL;
+	ecc16 = (unsigned short *)ecc_code;
+
+	ecc10[0] =  (ecc16[0] >>  0) & 0x3ff;
+	ecc10[1] = ((ecc16[0] >> 10) & 0x3f) | ((ecc16[1] << 6) & 0x3c0);
+	ecc10[2] =  (ecc16[1] >>  4) & 0x3ff;
+	ecc10[3] = ((ecc16[1] >> 14) & 0x3)  | ((ecc16[2] << 2) & 0x3fc);
+	ecc10[4] =  (ecc16[2] >>  8)         | ((ecc16[3] << 8) & 0x300);
+	ecc10[5] =  (ecc16[3] >>  2) & 0x3ff;
+	ecc10[6] = ((ecc16[3] >> 12) & 0xf)  | ((ecc16[4] << 4) & 0x3f0);
+	ecc10[7] =  (ecc16[4] >>  6) & 0x3ff;
+
+	/* Tell ECC controller about the expected ECC codes. */
+	for (i = 7; i >= 0; i--)
+		davinci_nand_writel(info, NAND_4BIT_ECC_LOAD_OFFSET, ecc10[i]);
+
+	/* Allow time for syndrome calculation ... then read it.
+	 * A syndrome of all zeroes 0 means no detected errors.
+	 */
+	davinci_nand_readl(info, NANDFSR_OFFSET);
+	nand_davinci_readecc_4bit(info, syndrome);
+	if (!(syndrome[0] | syndrome[1] | syndrome[2] | syndrome[3]))
+		return 0;
+
+	/*
+	 * Clear any previous address calculation by doing a dummy read of an
+	 * error address register.
+	 */
+	davinci_nand_readl(info, NAND_ERR_ADD1_OFFSET);
+
+	/* Start address calculation, and wait for it to complete.
+	 * We _could_ start reading more data while this is working,
+	 * to speed up the overall page read.
+	 */
+	davinci_nand_writel(info, NANDFCR_OFFSET,
+			davinci_nand_readl(info, NANDFCR_OFFSET) | BIT(13));
+
+	/*
+	 * ECC_STATE field reads 0x3 (Error correction complete) immediately
+	 * after setting the 4BITECC_ADD_CALC_START bit. So if you immediately
+	 * begin trying to poll for the state, you may fall right out of your
+	 * loop without any of the correction calculations having taken place.
+	 * The recommendation from the hardware team is to initially delay as
+	 * long as ECC_STATE reads less than 4. After that, ECC HW has entered
+	 * correction state.
+	 */
+	wait_on_timeout(100 * USECOND,
+			((davinci_nand_readl(info, NANDFSR_OFFSET) >> 8) & 0x0f)
+			< 4);
+
+	for (;;) {
+		u32	fsr = davinci_nand_readl(info, NANDFSR_OFFSET);
+
+		switch ((fsr >> 8) & 0x0f) {
+		case 0:		/* no error, should not happen */
+			davinci_nand_readl(info, NAND_ERR_ERRVAL1_OFFSET);
+			return 0;
+		case 1:		/* five or more errors detected */
+			davinci_nand_readl(info, NAND_ERR_ERRVAL1_OFFSET);
+			return -EIO;
+		case 2:		/* error addresses computed */
+		case 3:
+			num_errors = 1 + ((fsr >> 16) & 0x03);
+			goto correct;
+		default:	/* still working on it */
+			//cpu_relax();
+			continue;
+		}
+	}
+
+correct:
+	/* correct each error */
+	for (i = 0, corrected = 0; i < num_errors; i++) {
+		int error_address, error_value;
+
+		if (i > 1) {
+			error_address = davinci_nand_readl(info,
+						NAND_ERR_ADD2_OFFSET);
+			error_value = davinci_nand_readl(info,
+						NAND_ERR_ERRVAL2_OFFSET);
+		} else {
+			error_address = davinci_nand_readl(info,
+						NAND_ERR_ADD1_OFFSET);
+			error_value = davinci_nand_readl(info,
+						NAND_ERR_ERRVAL1_OFFSET);
+		}
+
+		if (i & 1) {
+			error_address >>= 16;
+			error_value >>= 16;
+		}
+		error_address &= 0x3ff;
+		error_address = (512 + 7) - error_address;
+
+		if (error_address < 512) {
+			data[error_address] ^= error_value;
+			corrected++;
+		}
+	}
+
+	return corrected;
+}
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * NOTE:  NAND boot requires ALE == EM_A[1], CLE == EM_A[2], so that's
+ * how these chips are normally wired.  This translates to both 8 and 16
+ * bit busses using ALE == BIT(3) in byte addresses, and CLE == BIT(4).
+ *
+ * For now we assume that configuration, or any other one which ignores
+ * the two LSBs for NAND access ... so we can issue 32-bit reads/writes
+ * and have that transparently morphed into multiple NAND operations.
+ */
+static void nand_davinci_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct davinci_nand_info *info = to_davinci_nand(mtd);
+
+	dev_dbg(info->dev, "%s\n", __func__);
+
+
+	if ((0x03 & ((unsigned)buf)) == 0 && (0x03 & len) == 0)
+		readsl(chip->IO_ADDR_R, buf, len >> 2);
+	else if ((0x01 & ((unsigned)buf)) == 0 && (0x01 & len) == 0)
+		readsw(chip->IO_ADDR_R, buf, len >> 1);
+	else
+		readsb(chip->IO_ADDR_R, buf, len);
+}
+
+static void nand_davinci_write_buf(struct mtd_info *mtd,
+		const uint8_t *buf, int len)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct davinci_nand_info *info = to_davinci_nand(mtd);
+
+	dev_dbg(info->dev, "%s\n", __func__);
+
+
+	if ((0x03 & ((unsigned)buf)) == 0 && (0x03 & len) == 0)
+		writesl(chip->IO_ADDR_R, buf, len >> 2);
+	else if ((0x01 & ((unsigned)buf)) == 0 && (0x01 & len) == 0)
+		writesw(chip->IO_ADDR_R, buf, len >> 1);
+	else
+		writesb(chip->IO_ADDR_R, buf, len);
+}
+
+/*
+ * Check hardware register for wait status. Returns 1 if device is ready,
+ * 0 if it is still busy.
+ */
+static int nand_davinci_dev_ready(struct mtd_info *mtd)
+{
+	struct davinci_nand_info *info = to_davinci_nand(mtd);
+
+	return davinci_nand_readl(info, NANDFSR_OFFSET) & BIT(0);
+}
+
+/*----------------------------------------------------------------------*/
+
+/* An ECC layout for using 4-bit ECC with small-page flash, storing
+ * ten ECC bytes plus the manufacturer's bad block marker byte, and
+ * and not overlapping the default BBT markers.
+ */
+static struct nand_ecclayout hwecc4_small = {
+	.eccbytes = 10,
+	.eccpos = { 0, 1, 2, 3, 4,
+		/* offset 5 holds the badblock marker */
+		6, 7,
+		13, 14, 15, },
+	.oobfree = {
+		{.offset = 8, .length = 5, },
+		{.offset = 16, },
+	},
+};
+
+/* An ECC layout for using 4-bit ECC with large-page (2048bytes) flash,
+ * storing ten ECC bytes plus the manufacturer's bad block marker byte,
+ * and not overlapping the default BBT markers.
+ */
+static struct nand_ecclayout hwecc4_2048 = {
+	.eccbytes = 40,
+	.eccpos = {
+		/* at the end of spare sector */
+		24, 25, 26, 27, 28, 29,	30, 31, 32, 33,
+		34, 35, 36, 37, 38, 39,	40, 41, 42, 43,
+		44, 45, 46, 47, 48, 49, 50, 51, 52, 53,
+		54, 55, 56, 57, 58, 59, 60, 61, 62, 63,
+		},
+	.oobfree = {
+		/* 2 bytes at offset 0 hold manufacturer badblock markers */
+		{.offset = 2, .length = 22, },
+		/* 5 bytes at offset 8 hold BBT markers */
+		/* 8 bytes at offset 16 hold JFFS2 clean markers */
+	},
+};
+
+static struct of_device_id davinci_nand_of_match[] = {
+	{.compatible = "ti,davinci-nand", },
+	{.compatible = "ti,keystone-nand", },
+	{},
+};
+
+static struct davinci_nand_pdata
+	*nand_davinci_get_pdata(struct device_d *dev)
+{
+	struct davinci_nand_pdata *pdata;
+	const char *mode;
+	u32 prop;
+
+	pdata = kzalloc(sizeof(struct davinci_nand_pdata),
+			GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+	if (!of_property_read_u32(dev->device_node,
+		"ti,davinci-chipselect", &prop))
+		pdata->chipsel = prop;
+	else
+		return ERR_PTR(-EINVAL);
+
+	if (!of_property_read_u32(dev->device_node,
+		"ti,davinci-mask-ale", &prop))
+		pdata->mask_ale = prop;
+	if (!of_property_read_u32(dev->device_node,
+		"ti,davinci-mask-cle", &prop))
+		pdata->mask_cle = prop;
+	if (!of_property_read_u32(dev->device_node,
+		"ti,davinci-mask-chipsel", &prop))
+		pdata->mask_chipsel = prop;
+	if (!of_property_read_string(dev->device_node,
+		"nand-ecc-mode", &mode) ||
+	    !of_property_read_string(dev->device_node,
+		"ti,davinci-ecc-mode", &mode)) {
+		if (!strncmp("none", mode, 4))
+			pdata->ecc_mode = NAND_ECC_NONE;
+		if (!strncmp("soft", mode, 4))
+			pdata->ecc_mode = NAND_ECC_SOFT;
+		if (!strncmp("hw", mode, 2))
+			pdata->ecc_mode = NAND_ECC_HW;
+	}
+	if (!of_property_read_u32(dev->device_node,
+		"ti,davinci-ecc-bits", &prop))
+		pdata->ecc_bits = prop;
+
+	prop = of_get_nand_bus_width(dev->device_node);
+	if (0 < prop || !of_property_read_u32(dev->device_node,
+		"ti,davinci-nand-buswidth", &prop))
+		if (prop == 16)
+			pdata->options |= NAND_BUSWIDTH_16;
+	if (of_property_read_bool(dev->device_node,
+		"nand-on-flash-bbt") ||
+	    of_property_read_bool(dev->device_node,
+		"ti,davinci-nand-use-bbt"))
+		pdata->bbt_options = NAND_BBT_USE_FLASH;
+
+	if (of_device_is_compatible(dev->device_node,
+				    "ti,keystone-nand")) {
+		pdata->options |= NAND_NO_SUBPAGE_WRITE;
+	}
+	return pdata;
+}
+
+static int nand_davinci_probe(struct device_d *dev)
+{
+	struct davinci_nand_pdata	*pdata;
+	struct davinci_nand_info	*info;
+	int				ret;
+	uint32_t			val;
+	nand_ecc_modes_t		ecc_mode;
+
+	pdata = nand_davinci_get_pdata(dev);
+
+	/* insist on board-specific configuration */
+	if (!pdata)
+		return -ENODEV;
+
+	/* which external chipselect will we be managing? */
+	if (pdata->chipsel < 0 || pdata->chipsel > 3)
+		return -ENODEV;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	//platform_set_drvdata(pdev, info);
+
+	info->dev		= dev;
+	info->base		= dev_request_mem_region(dev, 1);
+	info->vaddr		= dev_request_mem_region(dev, 0);
+
+	val = davinci_nand_readl(info, NRCSR_OFFSET);
+	dev_info(dev, "controller rev. %d.%d\n",
+	       (val >> 8) & 0xff, val & 0xff);
+
+	info->mtd.priv		= &info->chip;
+	info->mtd.name		= dev_name(dev);
+	info->mtd.parent	= dev;
+
+	info->chip.IO_ADDR_R	= info->vaddr;
+	info->chip.IO_ADDR_W	= info->vaddr;
+	info->chip.chip_delay	= 0;
+	info->chip.select_chip	= nand_davinci_select_chip;
+
+	/* options such as NAND_BBT_USE_FLASH */
+	info->chip.bbt_options	= pdata->bbt_options;
+	/* options such as 16-bit widths */
+	info->chip.options	= pdata->options;
+	info->chip.bbt_td	= pdata->bbt_td;
+	info->chip.bbt_md	= pdata->bbt_md;
+	//info->timing		= pdata->timing;
+
+	info->ioaddr		= (uint32_t __force) info->vaddr;
+
+	info->current_cs	= info->ioaddr;
+	info->core_chipsel	= pdata->chipsel;
+	info->mask_chipsel	= pdata->mask_chipsel;
+
+	/* use nandboot-capable ALE/CLE masks by default */
+	info->mask_ale		= pdata->mask_ale ? : MASK_ALE;
+	info->mask_cle		= pdata->mask_cle ? : MASK_CLE;
+
+	/* Set address of hardware control function */
+	info->chip.cmd_ctrl	= nand_davinci_hwcontrol;
+	info->chip.dev_ready	= nand_davinci_dev_ready;
+
+	/* Speed up buffer I/O */
+	info->chip.read_buf     = nand_davinci_read_buf;
+	info->chip.write_buf    = nand_davinci_write_buf;
+
+	/* Use board-specific ECC config */
+	ecc_mode		= pdata->ecc_mode;
+
+	ret = -EINVAL;
+	switch (ecc_mode) {
+	case NAND_ECC_NONE:
+	case NAND_ECC_SOFT:
+		pdata->ecc_bits = 0;
+		break;
+	case NAND_ECC_HW:
+		if (pdata->ecc_bits == 4) {
+			/* No sanity checks:  CPUs must support this,
+			 * and the chips may not use NAND_BUSWIDTH_16.
+			 */
+
+			/* No sharing 4-bit hardware between chipselects yet */
+			if (ecc4_busy)
+				ret = -EBUSY;
+			else
+				ecc4_busy = true;
+
+			if (ret == -EBUSY)
+				return ret;
+
+			info->chip.ecc.calculate = nand_davinci_calculate_4bit;
+			info->chip.ecc.correct = nand_davinci_correct_4bit;
+			info->chip.ecc.hwctl = nand_davinci_hwctl_4bit;
+			info->chip.ecc.bytes = 10;
+		} else {
+			info->chip.ecc.calculate = nand_davinci_calculate_1bit;
+			info->chip.ecc.correct = nand_davinci_correct_1bit;
+			info->chip.ecc.hwctl = nand_davinci_hwctl_1bit;
+			info->chip.ecc.bytes = 3;
+		}
+		info->chip.ecc.size = 512;
+		info->chip.ecc.strength = pdata->ecc_bits;
+		break;
+	default:
+		return -EINVAL;
+	}
+	info->chip.ecc.mode = ecc_mode;
+
+	info->clk = clk_get(dev, "aemif");
+	if (IS_ERR(info->clk)) {
+		ret = PTR_ERR(info->clk);
+		dev_dbg(dev, "unable to get AEMIF clock, err %d\n", ret);
+		return ret;
+	}
+
+	ret = clk_enable(info->clk);
+	if (ret < 0) {
+		dev_dbg(dev, "unable to enable AEMIF clock, err %d\n",
+			ret);
+		goto err_clk_enable;
+	}
+
+	/* put CSxNAND into NAND mode */
+	val = davinci_nand_readl(info, NANDFCR_OFFSET);
+	val |= BIT(info->core_chipsel);
+	davinci_nand_writel(info, NANDFCR_OFFSET, val);
+
+	/* Scan to find existence of the device(s) */
+	ret = nand_scan_ident(&info->mtd, pdata->mask_chipsel ? 2 : 1, NULL);
+	if (ret < 0) {
+		dev_dbg(dev, "no NAND chip(s) found\n");
+		goto err;
+	}
+
+	/* Update ECC layout if needed ... for 1-bit HW ECC, the default
+	 * is OK, but it allocates 6 bytes when only 3 are needed (for
+	 * each 512 bytes).  For the 4-bit HW ECC, that default is not
+	 * usable:  10 bytes are needed, not 6.
+	 */
+	if (pdata->ecc_bits == 4) {
+		int	chunks = info->mtd.writesize / 512;
+
+		if (!chunks || info->mtd.oobsize < 16) {
+			dev_dbg(dev, "too small\n");
+			ret = -EINVAL;
+			goto err;
+		}
+
+		/* For small page chips, preserve the manufacturer's
+		 * badblock marking data ... and make sure a flash BBT
+		 * table marker fits in the free bytes.
+		 */
+		if (chunks == 1) {
+			info->ecclayout = hwecc4_small;
+			info->ecclayout.oobfree[1].length =
+				info->mtd.oobsize - 16;
+			goto syndrome_done;
+		}
+		if (chunks == 4) {
+			info->ecclayout = hwecc4_2048;
+			info->chip.ecc.mode = NAND_ECC_HW_OOB_FIRST;
+			goto syndrome_done;
+		}
+
+		/* 4KiB page chips are not yet supported. The eccpos from
+		 * nand_ecclayout cannot hold 80 bytes and change to eccpos[]
+		 * breaks userspace ioctl interface with mtd-utils. Once we
+		 * resolve this issue, NAND_ECC_HW_OOB_FIRST mode can be used
+		 * for the 4KiB page chips.
+		 *
+		 * TODO: Note that nand_ecclayout has now been expanded and can
+		 *  hold plenty of OOB entries.
+		 */
+		dev_warn(dev, "no 4-bit ECC support yet "
+				"for 4KiB-page NAND\n");
+		ret = -EIO;
+		goto err;
+
+syndrome_done:
+		info->chip.ecc.layout = &info->ecclayout;
+	}
+
+	ret = nand_scan_tail(&info->mtd);
+	if (ret < 0)
+		goto err;
+
+	add_mtd_nand_device(&info->mtd, "nand");
+
+	return 0;
+
+err:
+	clk_disable(info->clk);
+
+err_clk_enable:
+	if (ecc_mode == NAND_ECC_HW_SYNDROME)
+		ecc4_busy = false;
+	return ret;
+}
+
+static struct driver_d nand_davinci_driver = {
+	.name	= "davinci_nand",
+	.probe	= nand_davinci_probe,
+	.of_compatible = DRV_OF_COMPAT(davinci_nand_of_match),
+};
+device_platform_driver(nand_davinci_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Texas Instruments");
+MODULE_DESCRIPTION("Davinci NAND flash driver");
+
-- 
2.1.4


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