[U-Boot] [PATCH 08/13 v4] ARM: OMAP3: Add NAND support

[dirk.behme at googlemail.com <dirk.behme@googlemail.com>]

Subject: [PATCH 08/13 v4] ARM: OMAP3: Add NAND support

From: Dirk Behme <dirk.behme@gmail.com>

Add NAND support

Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
Signed-off-by: Nishanth Menon <nm@ti.com>

---

Changes in version v4:

- Incorporate further review results from Scott Wood.
- Further sets of cleanup, making the logic generic, rename of files, better handling of ecc switch by Nishanth Menon.

Changes in version v3:

- Fix/update NAND driver and seperate it into an own patch as proposed by Scott Wood

 drivers/mtd/nand/Makefile              |    1 
 drivers/mtd/nand/omap_gpmc.c           |  337 +++++++++++++++++++++++++++++++++
 include/asm-arm/arch-omap3/omap_gpmc.h |   84 ++++++++
 3 files changed, 422 insertions(+)

Index: u-boot-arm/drivers/mtd/nand/Makefile
===================================================================
--- u-boot-arm.orig/drivers/mtd/nand/Makefile
+++ u-boot-arm/drivers/mtd/nand/Makefile
@@ -38,6 +38,7 @@ endif
 COBJS-$(CONFIG_NAND_FSL_ELBC) += fsl_elbc_nand.o
 COBJS-$(CONFIG_NAND_FSL_UPM) += fsl_upm.o
 COBJS-$(CONFIG_NAND_S3C64XX) += s3c64xx.o
+COBJS-$(CONFIG_NAND_OMAP_GPMC) += omap_gpmc.o
 endif
 
 COBJS	:= $(COBJS-y)
Index: u-boot-arm/drivers/mtd/nand/omap_gpmc.c
===================================================================
--- /dev/null
+++ u-boot-arm/drivers/mtd/nand/omap_gpmc.c
@@ -0,0 +1,337 @@
+/*
+ * (C) Copyright 2004-2008 Texas Instruments, <www.ti.com>
+ * Rohit Choraria <rohitkc@ti.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/errno.h>
+#include <asm/arch/mem.h>
+#include <asm/arch/omap_gpmc.h>
+#include <linux/mtd/nand_ecc.h>
+#include <nand.h>
+
+static unsigned char cs;
+static void __iomem *gpmc_cs_base_add;
+static struct nand_ecclayout hw_nand_oob = GPMC_NAND_HW_ECC_LAYOUT;
+
+/*
+ * omap_nand_hwcontrol - Set the address pointers corretly for the
+ *			following address/data/command operation
+ */
+static void omap_nand_hwcontrol(struct mtd_info *mtd, int cmd,
+				unsigned int ctrl)
+{
+	register struct nand_chip *this = mtd->priv;
+
+	/* Point the IO_ADDR to DATA and ADDRESS registers instead
+	 * of chip address
+	 */
+	switch (ctrl) {
+	case NAND_CTRL_CHANGE | NAND_CTRL_CLE:
+		this->IO_ADDR_W = gpmc_cs_base_add + GPMC_NAND_CMD;
+		break;
+	case NAND_CTRL_CHANGE | NAND_CTRL_ALE:
+		this->IO_ADDR_W = gpmc_cs_base_add + GPMC_NAND_ADR;
+		break;
+	case NAND_CTRL_CHANGE | NAND_NCE:
+		this->IO_ADDR_W = gpmc_cs_base_add + GPMC_NAND_DAT;
+		break;
+	}
+
+	if (cmd != NAND_CMD_NONE)
+		writeb(cmd, this->IO_ADDR_W);
+}
+
+/*
+ * omap_hwecc_init - Initialize the Hardware ECC for NAND flash in
+ *                   GPMC controller
+ * @mtd:        MTD device structure
+ *
+ */
+static void omap_hwecc_init(struct nand_chip *chip)
+{
+	/* Init ECC Control Register */
+	/* Clear all ECC | Enable Reg1 */
+	writel(ECCCLEAR | ECCRESULTREG1, GPMC_BASE + GPMC_ECC_CONTROL);
+	writel(ECCSIZE1 | ECCSIZE0 | ECCSIZE0SEL,
+		GPMC_BASE + GPMC_ECC_SIZE_CONFIG);
+}
+
+/*
+ * gen_true_ecc - This function will generate true ECC value, which
+ * can be used when correcting data read from NAND flash memory core
+ *
+ * @ecc_buf:	buffer to store ecc code
+ *
+ * @return:	re-formatted ECC value
+ */
+static unsigned int gen_true_ecc(u8 *ecc_buf)
+{
+	return ecc_buf[0] | (ecc_buf[1] << 16) | ((ecc_buf[2] & 0xF0) << 20) |
+		((ecc_buf[2] & 0x0F) << 8);
+}
+
+/*
+ * omap_correct_data - Compares the ecc read from nand spare area with ECC
+ * registers values and corrects one bit error if it has occured
+ * Further details can be had from OMAP TRM and the following selected links:
+ * http://en.wikipedia.org/wiki/Hamming_code
+ * http://www.cs.utexas.edu/users/plaxton/c/337/05f/slides/ErrorCorrection-4.pdf
+ *
+ * @mtd:		 MTD device structure
+ * @dat:		 page data
+ * @read_ecc:		 ecc read from nand flash
+ * @calc_ecc:		 ecc read from ECC registers
+ *
+ * @return 0 if data is OK or corrected, else returns -1
+ */
+static int omap_correct_data(struct mtd_info *mtd, u_char *dat,
+				u_char *read_ecc, u_char *calc_ecc)
+{
+	unsigned int orig_ecc, new_ecc, res, hm;
+	unsigned short parity_bits, byte;
+	unsigned char bit;
+
+	/* Regenerate the orginal ECC */
+	orig_ecc = gen_true_ecc(read_ecc);
+	new_ecc = gen_true_ecc(calc_ecc);
+	/* Get the XOR of real ecc */
+	res = orig_ecc ^ new_ecc;
+	if (res) {
+		/* Get the hamming width */
+		hm = hweight32(res);
+		/* Single bit errors can be corrected! */
+		if (hm == 12) {
+			/* Correctable data! */
+			parity_bits = res >> 16;
+			bit = (parity_bits & 0x7);
+			byte = (parity_bits >> 3) & 0x1FF;
+			/* Flip the bit to correct */
+			dat[byte] ^= (0x1 << bit);
+		} else if (hm == 1) {
+			printf("Error: Ecc is wrong\n");
+			/* ECC itself is corrupted */
+			return 2;
+		} else {
+			/*
+			 * hm distance != parity pairs OR one, could mean 2 bit
+			 * error OR potentially be on a blank page..
+			 * orig_ecc: contains spare area data from nand flash.
+			 * new_ecc: generated ecc while reading data area.
+			 * Note: if the ecc = 0, all data bits from which it was
+			 * generated are 0xFF.
+			 * The 3 byte(24 bits) ecc is generated per 512byte
+			 * chunk of a page. If orig_ecc(from spare area)
+			 * is 0xFF && new_ecc(computed now from data area)=0x0,
+			 * this means that data area is 0xFF and spare area is
+			 * 0xFF. A sure sign of a erased page!
+			 */
+			if ((orig_ecc == 0x0FFF0FFF) && (new_ecc == 0x00000000))
+				return 0;
+			printf("Error: Bad compare! failed\n");
+			/* detected 2 bit error */
+			return -1;
+		}
+	}
+	return 0;
+}
+
+/*
+ *  omap_calculate_ecc - Generate non-inverted ECC bytes.
+ *
+ *  Using noninverted ECC can be considered ugly since writing a blank
+ *  page ie. padding will clear the ECC bytes. This is no problem as
+ *  long nobody is trying to write data on the seemingly unused page.
+ *  Reading an erased page will produce an ECC mismatch between
+ *  generated and read ECC bytes that has to be dealt with separately.
+ *  E.g. if page is 0xFF (fresh erased), and if HW ECC engine within GPMC
+ *  is used, the result of read will be 0x0 while the ECC offsets of the
+ *  spare area will be 0xFF which will result in an ECC mismatch.
+ *  @mtd:	MTD structure
+ *  @dat:	unused
+ *  @ecc_code:	ecc_code buffer
+ */
+static int omap_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
+				u_char *ecc_code)
+{
+	unsigned long val;
+
+	/* Start Reading from HW ECC1_Result = 0x200 */
+	val = readl(GPMC_BASE + GPMC_ECC1_RESULT);
+
+	ecc_code[0] = val & 0xFF;
+	ecc_code[1] = (val >> 16) & 0xFF;
+	ecc_code[2] = ((val >> 8) & 0x0F) | ((val >> 20) & 0xF0);
+
+	/* Stop reading anymore ECC vals and clear old results
+	 * enable will be called if more reads are required
+	 */
+	writel(0x000, GPMC_BASE + GPMC_ECC_CONFIG);
+
+	return 0;
+}
+
+/*
+ * omap_enable_ecc - This function enables the hardware ecc functionality
+ * @mtd:        MTD device structure
+ * @mode:       Read/Write mode
+ */
+static void omap_enable_hwecc(struct mtd_info *mtd, int mode)
+{
+	struct nand_chip *chip = mtd->priv;
+	unsigned int val, dev_width = (chip->options & NAND_BUSWIDTH_16) >> 1;
+
+	switch (mode) {
+	case NAND_ECC_READ:
+	case NAND_ECC_WRITE:
+		/* Clear the ecc result registers, select ecc reg as 1 */
+		writel(ECCCLEAR | ECCRESULTREG1, GPMC_BASE + GPMC_ECC_CONTROL);
+		/* Size 0 = 0xFF, Size1 is 0xFF - both are 512 bytes
+		 * tell all regs to generate size0 sized regs
+		 * we just have a single ECC engine for all CS
+		 */
+		writel(ECCSIZE1 | ECCSIZE0 | ECCSIZE0SEL,
+			GPMC_BASE + GPMC_ECC_SIZE_CONFIG);
+		val = (dev_width << 7) | (cs << 1) | (0x1);
+		writel(val, GPMC_BASE + GPMC_ECC_CONFIG);
+		break;
+	default:
+		printf("Error: Unrecognized Mode[%d]!\n", mode);
+		break;
+	}
+}
+
+/**
+ * omap_nand_switch_ecc - switch the ECC operation b/w h/w ecc and s/w ecc.
+ * The default is to come up on s/w ecc
+ *
+ * @hardware - 1 -switch to h/w ecc, 0 - s/w ecc
+ *
+ */
+void omap_nand_switch_ecc(int hardware)
+{
+	struct nand_chip *nand;
+	struct mtd_info *mtd;
+
+	if (nand_curr_device < 0 ||
+		nand_curr_device >= CONFIG_SYS_MAX_NAND_DEVICE ||
+		!nand_info[nand_curr_device].name) {
+		printf("Error: Can't switch ecc, no devices available\n");
+		return;
+	}
+
+	mtd = &nand_info[nand_curr_device];
+	nand = mtd->priv;
+
+	/* clean up allocated buffers */
+	nand_release(mtd);
+	/* mark me unscanned */
+	nand->options &= ~NAND_BBT_SCANNED;
+
+	/* Setup the ecc configurations again */
+	if (!hardware) {
+		nand->ecc.mode = NAND_ECC_SOFT;
+		/* Use mtd default settings */
+		nand->ecc.layout = NULL;
+	} else {
+		nand->ecc.mode = NAND_ECC_HW;
+		nand->ecc.layout = &hw_nand_oob;
+		nand->ecc.size = 512;
+		nand->ecc.bytes = 3;
+		nand->ecc.steps = hw_nand_oob.eccbytes / nand->ecc.bytes;
+		nand->ecc.hwctl = omap_enable_hwecc;
+		nand->ecc.correct = omap_correct_data;
+		nand->ecc.calculate = omap_calculate_ecc;
+		omap_hwecc_init(nand);
+	}
+
+	/* Update NAND handling after ECC mode switch */
+	nand_scan_tail(mtd);
+}
+
+/*
+ * Board-specific NAND initialization. The following members of the
+ * argument are board-specific:
+ * - IO_ADDR_R: address to read the 8 I/O lines of the flash device
+ * - IO_ADDR_W: address to write the 8 I/O lines of the flash device
+ * - cmd_ctrl: hardwarespecific function for accesing control-lines
+ * - waitfunc: hardwarespecific function for accesing device ready/busy line
+ * - ecc.hwctl: function to enable (reset) hardware ecc generator
+ * - ecc.mode: mode of ecc, see defines
+ * - chip_delay: chip dependent delay for transfering data from array to
+ *   read regs (tR)
+ * - options: various chip options. They can partly be set to inform
+ *   nand_scan about special functionality. See the defines for further
+ *   explanation
+ */
+int board_nand_init(struct nand_chip *nand)
+{
+	int gpmc_config = 0;
+	cs = 0;
+
+	/* xloader/Uboot's gpmc configuration would have configured GPMC for
+	 * nand type of memory. The following logic scans and latches on to the
+	 * first CS with NAND type memory.
+	 * TBD: need to make this logic generic to handle multiple CS NAND
+	 * devices.
+	 */
+	while (cs < GPMC_MAX_CS) {
+		/* Each GPMC set for a single CS is@offset 0x30
+		 * - already remapped for us
+		 */
+		gpmc_cs_base_add = (void __iomem *)(GPMC_CONFIG_CS0 +
+							(cs * 0x30));
+		/* Check if NAND type is set */
+		if ((readl(gpmc_cs_base_add + GPMC_CONFIG1) & 0xC00) ==
+			0x800) {
+			/* Found it!! */
+			break;
+		}
+		cs++;
+	}
+	if (cs >= GPMC_MAX_CS) {
+		printf("NAND: Unable to find NAND settings in "
+			"GPMC Configuration - quitting\n");
+		return -ENODEV;
+	}
+
+	gpmc_config = readl(GPMC_CONFIG);
+	/* Disable Write protect */
+	gpmc_config |= 0x10;
+	writel(gpmc_config, GPMC_CONFIG);
+
+	nand->IO_ADDR_R = gpmc_cs_base_add + GPMC_NAND_DAT;
+	nand->IO_ADDR_W = gpmc_cs_base_add + GPMC_NAND_CMD;
+
+	nand->cmd_ctrl = omap_nand_hwcontrol;
+	nand->options = NAND_NO_PADDING | NAND_CACHEPRG | NAND_NO_AUTOINCR |
+			NAND_NO_AUTOINCR;
+	/* If we are 16 bit dev, our gpmc config tells us that */
+	if ((readl(gpmc_cs_base_add) & 0x3000) == 0x1000)
+		nand->options |= NAND_BUSWIDTH_16;
+
+	nand->chip_delay = 100;
+	/* Default ECC mode */
+	nand->ecc.mode = NAND_ECC_SOFT;
+
+	return 0;
+}
Index: u-boot-arm/include/asm-arm/arch-omap3/omap_gpmc.h
===================================================================
--- /dev/null
+++ u-boot-arm/include/asm-arm/arch-omap3/omap_gpmc.h
@@ -0,0 +1,84 @@
+/*
+ * (C) Copyright 2004-2008 Texas Instruments, <www.ti.com>
+ * Rohit Choraria <rohitkc@ti.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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
+ */
+#ifndef __ASM_ARCH_OMAP_GPMC_H
+#define __ASM_ARCH_OMAP_GPMC_H
+
+#define GPMC_BUF_EMPTY	0
+#define GPMC_BUF_FULL	1
+
+#define ECCCLEAR	(0x1 << 8)
+#define ECCRESULTREG1	(0x1 << 0)
+#define ECCSIZE512BYTE	0xFF
+#define ECCSIZE1	(ECCSIZE512BYTE << 22)
+#define ECCSIZE0	(ECCSIZE512BYTE << 12)
+#define ECCSIZE0SEL	(0x000 << 0)
+
+/* Generic ECC Layouts */
+/* Large Page x8 NAND device Layout */
+#ifdef GPMC_NAND_ECC_LP_x8_LAYOUT
+#define GPMC_NAND_HW_ECC_LAYOUT {\
+	.eccbytes = 12,\
+	.eccpos = {1, 2, 3, 4, 5, 6, 7, 8,\
+		9, 10, 11, 12},\
+	.oobfree = {\
+		{.offset = 13,\
+		 .length = 51 } } \
+}
+#endif
+
+/* Large Page x16 NAND device Layout */
+#ifdef GPMC_NAND_ECC_LP_x16_LAYOUT
+#define GPMC_NAND_HW_ECC_LAYOUT {\
+	.eccbytes = 12,\
+	.eccpos = {2, 3, 4, 5, 6, 7, 8, 9,\
+		10, 11, 12, 13},\
+	.oobfree = {\
+		{.offset = 14,\
+		 .length = 50 } } \
+}
+#endif
+
+/* Small Page x8 NAND device Layout */
+#ifdef GPMC_NAND_ECC_SP_x8_LAYOUT
+#define GPMC_NAND_HW_ECC_LAYOUT {\
+	.eccbytes = 3,\
+	.eccpos = {1, 2, 3},\
+	.oobfree = {\
+		{.offset = 4,\
+		 .length = 13 } } \
+}
+#endif
+
+/* Small Page x16 NAND device Layout */
+#ifdef GPMC_NAND_ECC_SP_x16_LAYOUT
+#define GPMC_NAND_HW_ECC_LAYOUT {\
+	.eccbytes = 3,\
+	.eccpos = {2, 3, 4},\
+	.oobfree = {\
+		{.offset = 4,\
+		 .length = 12 } } \
+}
+#endif
+
+#endif /* __ASM_ARCH_OMAP_GPMC_H */
+