OMAP3: Add NAND support

Add NAND support.

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Syed Mohammed Khasim <khasim@ti.com>
Signed-off-by: Dirk Behme <dirk.behme@googlemail.com>

1 files changed, 353 insertions, 0 deletions

diff --git a/drivers/mtd/nand/omap_gpmc.c b/drivers/mtd/nand/omap_gpmc.c
new file mode 100644
index 0000000..5f8ed39
--- /dev/null
+++ b/drivers/mtd/nand/omap_gpmc.c
@@ -0,0 +1,353 @@
+/*
+ * (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 uint8_t cs;
+static gpmc_t *gpmc_base = (gpmc_t *)GPMC_BASE;
+static gpmc_csx_t *gpmc_cs_base;
+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, int32_t cmd,
+				uint32_t 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 = (void __iomem *)&gpmc_cs_base->nand_cmd;
+		break;
+	case NAND_CTRL_CHANGE | NAND_CTRL_ALE:
+		this->IO_ADDR_W = (void __iomem *)&gpmc_cs_base->nand_adr;
+		break;
+	case NAND_CTRL_CHANGE | NAND_NCE:
+		this->IO_ADDR_W = (void __iomem *)&gpmc_cs_base->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->ecc_control);
+	writel(ECCSIZE1 | ECCSIZE0 | ECCSIZE0SEL, &gpmc_base->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 uint32_t gen_true_ecc(uint8_t *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, uint8_t *dat,
+				uint8_t *read_ecc, uint8_t *calc_ecc)
+{
+	uint32_t orig_ecc, new_ecc, res, hm;
+	uint16_t parity_bits, byte;
+	uint8_t 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 uint8_t *dat,
+				uint8_t *ecc_code)
+{
+	u_int32_t val;
+
+	/* Start Reading from HW ECC1_Result = 0x200 */
+	val = readl(&gpmc_base->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->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, int32_t mode)
+{
+	struct nand_chip *chip = mtd->priv;
+	uint32_t 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->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->ecc_size_config);
+		val = (dev_width << 7) | (cs << 1) | (0x1);
+		writel(val, &gpmc_base->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(int32_t 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;
+
+	nand->options |= NAND_OWN_BUFFERS;
+
+	/* Reset ecc interface */
+	nand->ecc.read_page = NULL;
+	nand->ecc.write_page = NULL;
+	nand->ecc.read_oob = NULL;
+	nand->ecc.write_oob = NULL;
+	nand->ecc.hwctl = NULL;
+	nand->ecc.correct = NULL;
+	nand->ecc.calculate = NULL;
+
+	/* Setup the ecc configurations again */
+	if (hardware) {
+		nand->ecc.mode = NAND_ECC_HW;
+		nand->ecc.layout = &hw_nand_oob;
+		nand->ecc.size = 512;
+		nand->ecc.bytes = 3;
+		nand->ecc.hwctl = omap_enable_hwecc;
+		nand->ecc.correct = omap_correct_data;
+		nand->ecc.calculate = omap_calculate_ecc;
+		omap_hwecc_init(nand);
+		printf("HW ECC selected\n");
+	} else {
+		nand->ecc.mode = NAND_ECC_SOFT;
+		/* Use mtd default settings */
+		nand->ecc.layout = NULL;
+		printf("SW ECC selected\n");
+	}
+
+	/* Update NAND handling after ECC mode switch */
+	nand_scan_tail(mtd);
+
+	nand->options &= ~NAND_OWN_BUFFERS;
+}
+
+/*
+ * 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)
+{
+	int32_t 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 at offset 0x30
+		 * - already remapped for us
+		 */
+		gpmc_cs_base = (gpmc_csx_t *)(GPMC_CONFIG_CS0_BASE +
+				(cs * GPMC_CONFIG_WIDTH));
+		/* Check if NAND type is set */
+		if ((readl(&gpmc_cs_base->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_base->config);
+	/* Disable Write protect */
+	gpmc_config |= 0x10;
+	writel(gpmc_config, &gpmc_base->config);
+
+	nand->IO_ADDR_R = (void __iomem *)&gpmc_cs_base->nand_dat;
+	nand->IO_ADDR_W = (void __iomem *)&gpmc_cs_base->nand_cmd;
+
+	nand->cmd_ctrl = omap_nand_hwcontrol;
+	nand->options = NAND_NO_PADDING | NAND_CACHEPRG | NAND_NO_AUTOINCR;
+	/* If we are 16 bit dev, our gpmc config tells us that */
+	if ((readl(gpmc_cs_base) & 0x3000) == 0x1000)
+		nand->options |= NAND_BUSWIDTH_16;
+
+	nand->chip_delay = 100;
+	/* Default ECC mode */
+	nand->ecc.mode = NAND_ECC_SOFT;
+
+	return 0;
+}