/* * (C) Copyright 2004-2008 Texas Instruments, * Rohit Choraria * * 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 #include #include #include #include #include #include static uint8_t cs; static gpmc_t *gpmc_base = (gpmc_t *)GPMC_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_base->cs[cs].nand_cmd; break; case NAND_CTRL_CHANGE | NAND_CTRL_ALE: this->IO_ADDR_W = (void __iomem *)&gpmc_base->cs[cs].nand_adr; break; case NAND_CTRL_CHANGE | NAND_NCE: this->IO_ADDR_W = (void __iomem *)&gpmc_base->cs[cs].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) { /* Check if NAND type is set */ if ((readl(&gpmc_base->cs[cs].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_base->cs[cs].nand_dat; nand->IO_ADDR_W = (void __iomem *)&gpmc_base->cs[cs].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_base->cs[cs].config1) & 0x3000) == 0x1000) nand->options |= NAND_BUSWIDTH_16; nand->chip_delay = 100; /* Default ECC mode */ nand->ecc.mode = NAND_ECC_SOFT; return 0; }