diff options
Diffstat (limited to 'drivers/mtd/nand/omap_gpmc.c')
| -rw-r--r-- | drivers/mtd/nand/omap_gpmc.c | 353 |
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 000000000..5f8ed3984 --- /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; +} |