diff options
Diffstat (limited to 'drivers/mtd/nand/raw/ingenic/jz4740_ecc.c')
| -rw-r--r-- | drivers/mtd/nand/raw/ingenic/jz4740_ecc.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/drivers/mtd/nand/raw/ingenic/jz4740_ecc.c b/drivers/mtd/nand/raw/ingenic/jz4740_ecc.c new file mode 100644 index 000000000000..13fea645c7f0 --- /dev/null +++ b/drivers/mtd/nand/raw/ingenic/jz4740_ecc.c @@ -0,0 +1,197 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * JZ4740 ECC controller driver + * + * Copyright (c) 2019 Paul Cercueil <paul@crapouillou.net> + * + * based on jz4740-nand.c + */ + +#include <linux/bitops.h> +#include <linux/device.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> + +#include "ingenic_ecc.h" + +#define JZ_REG_NAND_ECC_CTRL 0x00 +#define JZ_REG_NAND_DATA 0x04 +#define JZ_REG_NAND_PAR0 0x08 +#define JZ_REG_NAND_PAR1 0x0C +#define JZ_REG_NAND_PAR2 0x10 +#define JZ_REG_NAND_IRQ_STAT 0x14 +#define JZ_REG_NAND_IRQ_CTRL 0x18 +#define JZ_REG_NAND_ERR(x) (0x1C + ((x) << 2)) + +#define JZ_NAND_ECC_CTRL_PAR_READY BIT(4) +#define JZ_NAND_ECC_CTRL_ENCODING BIT(3) +#define JZ_NAND_ECC_CTRL_RS BIT(2) +#define JZ_NAND_ECC_CTRL_RESET BIT(1) +#define JZ_NAND_ECC_CTRL_ENABLE BIT(0) + +#define JZ_NAND_STATUS_ERR_COUNT (BIT(31) | BIT(30) | BIT(29)) +#define JZ_NAND_STATUS_PAD_FINISH BIT(4) +#define JZ_NAND_STATUS_DEC_FINISH BIT(3) +#define JZ_NAND_STATUS_ENC_FINISH BIT(2) +#define JZ_NAND_STATUS_UNCOR_ERROR BIT(1) +#define JZ_NAND_STATUS_ERROR BIT(0) + +static const uint8_t empty_block_ecc[] = { + 0xcd, 0x9d, 0x90, 0x58, 0xf4, 0x8b, 0xff, 0xb7, 0x6f +}; + +static void jz4740_ecc_reset(struct ingenic_ecc *ecc, bool calc_ecc) +{ + uint32_t reg; + + /* Clear interrupt status */ + writel(0, ecc->base + JZ_REG_NAND_IRQ_STAT); + + /* Initialize and enable ECC hardware */ + reg = readl(ecc->base + JZ_REG_NAND_ECC_CTRL); + reg |= JZ_NAND_ECC_CTRL_RESET; + reg |= JZ_NAND_ECC_CTRL_ENABLE; + reg |= JZ_NAND_ECC_CTRL_RS; + if (calc_ecc) /* calculate ECC from data */ + reg |= JZ_NAND_ECC_CTRL_ENCODING; + else /* correct data from ECC */ + reg &= ~JZ_NAND_ECC_CTRL_ENCODING; + + writel(reg, ecc->base + JZ_REG_NAND_ECC_CTRL); +} + +static int jz4740_ecc_calculate(struct ingenic_ecc *ecc, + struct ingenic_ecc_params *params, + const u8 *buf, u8 *ecc_code) +{ + uint32_t reg, status; + unsigned int timeout = 1000; + int i; + + jz4740_ecc_reset(ecc, true); + + do { + status = readl(ecc->base + JZ_REG_NAND_IRQ_STAT); + } while (!(status & JZ_NAND_STATUS_ENC_FINISH) && --timeout); + + if (timeout == 0) + return -ETIMEDOUT; + + reg = readl(ecc->base + JZ_REG_NAND_ECC_CTRL); + reg &= ~JZ_NAND_ECC_CTRL_ENABLE; + writel(reg, ecc->base + JZ_REG_NAND_ECC_CTRL); + + for (i = 0; i < params->bytes; ++i) + ecc_code[i] = readb(ecc->base + JZ_REG_NAND_PAR0 + i); + + /* + * If the written data is completely 0xff, we also want to write 0xff as + * ECC, otherwise we will get in trouble when doing subpage writes. + */ + if (memcmp(ecc_code, empty_block_ecc, ARRAY_SIZE(empty_block_ecc)) == 0) + memset(ecc_code, 0xff, ARRAY_SIZE(empty_block_ecc)); + + return 0; +} + +static void jz_nand_correct_data(uint8_t *buf, int index, int mask) +{ + int offset = index & 0x7; + uint16_t data; + + index += (index >> 3); + + data = buf[index]; + data |= buf[index + 1] << 8; + + mask ^= (data >> offset) & 0x1ff; + data &= ~(0x1ff << offset); + data |= (mask << offset); + + buf[index] = data & 0xff; + buf[index + 1] = (data >> 8) & 0xff; +} + +static int jz4740_ecc_correct(struct ingenic_ecc *ecc, + struct ingenic_ecc_params *params, + u8 *buf, u8 *ecc_code) +{ + int i, error_count, index; + uint32_t reg, status, error; + unsigned int timeout = 1000; + + jz4740_ecc_reset(ecc, false); + + for (i = 0; i < params->bytes; ++i) + writeb(ecc_code[i], ecc->base + JZ_REG_NAND_PAR0 + i); + + reg = readl(ecc->base + JZ_REG_NAND_ECC_CTRL); + reg |= JZ_NAND_ECC_CTRL_PAR_READY; + writel(reg, ecc->base + JZ_REG_NAND_ECC_CTRL); + + do { + status = readl(ecc->base + JZ_REG_NAND_IRQ_STAT); + } while (!(status & JZ_NAND_STATUS_DEC_FINISH) && --timeout); + + if (timeout == 0) + return -ETIMEDOUT; + + reg = readl(ecc->base + JZ_REG_NAND_ECC_CTRL); + reg &= ~JZ_NAND_ECC_CTRL_ENABLE; + writel(reg, ecc->base + JZ_REG_NAND_ECC_CTRL); + + if (status & JZ_NAND_STATUS_ERROR) { + if (status & JZ_NAND_STATUS_UNCOR_ERROR) + return -EBADMSG; + + error_count = (status & JZ_NAND_STATUS_ERR_COUNT) >> 29; + + for (i = 0; i < error_count; ++i) { + error = readl(ecc->base + JZ_REG_NAND_ERR(i)); + index = ((error >> 16) & 0x1ff) - 1; + if (index >= 0 && index < params->size) + jz_nand_correct_data(buf, index, error & 0x1ff); + } + + return error_count; + } + + return 0; +} + +static void jz4740_ecc_disable(struct ingenic_ecc *ecc) +{ + u32 reg; + + writel(0, ecc->base + JZ_REG_NAND_IRQ_STAT); + reg = readl(ecc->base + JZ_REG_NAND_ECC_CTRL); + reg &= ~JZ_NAND_ECC_CTRL_ENABLE; + writel(reg, ecc->base + JZ_REG_NAND_ECC_CTRL); +} + +static const struct ingenic_ecc_ops jz4740_ecc_ops = { + .disable = jz4740_ecc_disable, + .calculate = jz4740_ecc_calculate, + .correct = jz4740_ecc_correct, +}; + +static const struct of_device_id jz4740_ecc_dt_match[] = { + { .compatible = "ingenic,jz4740-ecc", .data = &jz4740_ecc_ops }, + {}, +}; +MODULE_DEVICE_TABLE(of, jz4740_ecc_dt_match); + +static struct platform_driver jz4740_ecc_driver = { + .probe = ingenic_ecc_probe, + .driver = { + .name = "jz4740-ecc", + .of_match_table = jz4740_ecc_dt_match, + }, +}; +module_platform_driver(jz4740_ecc_driver); + +MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>"); +MODULE_DESCRIPTION("Ingenic JZ4740 ECC controller driver"); +MODULE_LICENSE("GPL v2"); |