--- /dev/null
+/*
+ * (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;
+}
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