diff options
Diffstat (limited to 'drivers/mtd/devices/elm.c')
| -rw-r--r-- | drivers/mtd/devices/elm.c | 404 |
1 files changed, 404 insertions, 0 deletions
diff --git a/drivers/mtd/devices/elm.c b/drivers/mtd/devices/elm.c new file mode 100644 index 00000000000..2ec5da9ee24 --- /dev/null +++ b/drivers/mtd/devices/elm.c @@ -0,0 +1,404 @@ +/* + * Error Location Module + * + * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/ + * + * 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. + * + */ + +#include <linux/platform_device.h> +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/pm_runtime.h> +#include <linux/platform_data/elm.h> + +#define ELM_IRQSTATUS 0x018 +#define ELM_IRQENABLE 0x01c +#define ELM_LOCATION_CONFIG 0x020 +#define ELM_PAGE_CTRL 0x080 +#define ELM_SYNDROME_FRAGMENT_0 0x400 +#define ELM_SYNDROME_FRAGMENT_6 0x418 +#define ELM_LOCATION_STATUS 0x800 +#define ELM_ERROR_LOCATION_0 0x880 + +/* ELM Interrupt Status Register */ +#define INTR_STATUS_PAGE_VALID BIT(8) + +/* ELM Interrupt Enable Register */ +#define INTR_EN_PAGE_MASK BIT(8) + +/* ELM Location Configuration Register */ +#define ECC_BCH_LEVEL_MASK 0x3 + +/* ELM syndrome */ +#define ELM_SYNDROME_VALID BIT(16) + +/* ELM_LOCATION_STATUS Register */ +#define ECC_CORRECTABLE_MASK BIT(8) +#define ECC_NB_ERRORS_MASK 0x1f + +/* ELM_ERROR_LOCATION_0-15 Registers */ +#define ECC_ERROR_LOCATION_MASK 0x1fff + +#define ELM_ECC_SIZE 0x7ff + +#define SYNDROME_FRAGMENT_REG_SIZE 0x40 +#define ERROR_LOCATION_SIZE 0x100 + +struct elm_info { + struct device *dev; + void __iomem *elm_base; + struct completion elm_completion; + struct list_head list; + enum bch_ecc bch_type; +}; + +static LIST_HEAD(elm_devices); + +static void elm_write_reg(struct elm_info *info, int offset, u32 val) +{ + writel(val, info->elm_base + offset); +} + +static u32 elm_read_reg(struct elm_info *info, int offset) +{ + return readl(info->elm_base + offset); +} + +/** + * elm_config - Configure ELM module + * @dev: ELM device + * @bch_type: Type of BCH ecc + */ +void elm_config(struct device *dev, enum bch_ecc bch_type) +{ + u32 reg_val; + struct elm_info *info = dev_get_drvdata(dev); + + reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16); + elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val); + info->bch_type = bch_type; +} +EXPORT_SYMBOL(elm_config); + +/** + * elm_configure_page_mode - Enable/Disable page mode + * @info: elm info + * @index: index number of syndrome fragment vector + * @enable: enable/disable flag for page mode + * + * Enable page mode for syndrome fragment index + */ +static void elm_configure_page_mode(struct elm_info *info, int index, + bool enable) +{ + u32 reg_val; + + reg_val = elm_read_reg(info, ELM_PAGE_CTRL); + if (enable) + reg_val |= BIT(index); /* enable page mode */ + else + reg_val &= ~BIT(index); /* disable page mode */ + + elm_write_reg(info, ELM_PAGE_CTRL, reg_val); +} + +/** + * elm_load_syndrome - Load ELM syndrome reg + * @info: elm info + * @err_vec: elm error vectors + * @ecc: buffer with calculated ecc + * + * Load syndrome fragment registers with calculated ecc in reverse order. + */ +static void elm_load_syndrome(struct elm_info *info, + struct elm_errorvec *err_vec, u8 *ecc) +{ + int i, offset; + u32 val; + + for (i = 0; i < ERROR_VECTOR_MAX; i++) { + + /* Check error reported */ + if (err_vec[i].error_reported) { + elm_configure_page_mode(info, i, true); + offset = ELM_SYNDROME_FRAGMENT_0 + + SYNDROME_FRAGMENT_REG_SIZE * i; + + /* BCH8 */ + if (info->bch_type) { + + /* syndrome fragment 0 = ecc[9-12B] */ + val = cpu_to_be32(*(u32 *) &ecc[9]); + elm_write_reg(info, offset, val); + + /* syndrome fragment 1 = ecc[5-8B] */ + offset += 4; + val = cpu_to_be32(*(u32 *) &ecc[5]); + elm_write_reg(info, offset, val); + + /* syndrome fragment 2 = ecc[1-4B] */ + offset += 4; + val = cpu_to_be32(*(u32 *) &ecc[1]); + elm_write_reg(info, offset, val); + + /* syndrome fragment 3 = ecc[0B] */ + offset += 4; + val = ecc[0]; + elm_write_reg(info, offset, val); + } else { + /* syndrome fragment 0 = ecc[20-52b] bits */ + val = (cpu_to_be32(*(u32 *) &ecc[3]) >> 4) | + ((ecc[2] & 0xf) << 28); + elm_write_reg(info, offset, val); + + /* syndrome fragment 1 = ecc[0-20b] bits */ + offset += 4; + val = cpu_to_be32(*(u32 *) &ecc[0]) >> 12; + elm_write_reg(info, offset, val); + } + } + + /* Update ecc pointer with ecc byte size */ + ecc += info->bch_type ? BCH8_SIZE : BCH4_SIZE; + } +} + +/** + * elm_start_processing - start elm syndrome processing + * @info: elm info + * @err_vec: elm error vectors + * + * Set syndrome valid bit for syndrome fragment registers for which + * elm syndrome fragment registers are loaded. This enables elm module + * to start processing syndrome vectors. + */ +static void elm_start_processing(struct elm_info *info, + struct elm_errorvec *err_vec) +{ + int i, offset; + u32 reg_val; + + /* + * Set syndrome vector valid, so that ELM module + * will process it for vectors error is reported + */ + for (i = 0; i < ERROR_VECTOR_MAX; i++) { + if (err_vec[i].error_reported) { + offset = ELM_SYNDROME_FRAGMENT_6 + + SYNDROME_FRAGMENT_REG_SIZE * i; + reg_val = elm_read_reg(info, offset); + reg_val |= ELM_SYNDROME_VALID; + elm_write_reg(info, offset, reg_val); + } + } +} + +/** + * elm_error_correction - locate correctable error position + * @info: elm info + * @err_vec: elm error vectors + * + * On completion of processing by elm module, error location status + * register updated with correctable/uncorrectable error information. + * In case of correctable errors, number of errors located from + * elm location status register & read the positions from + * elm error location register. + */ +static void elm_error_correction(struct elm_info *info, + struct elm_errorvec *err_vec) +{ + int i, j, errors = 0; + int offset; + u32 reg_val; + + for (i = 0; i < ERROR_VECTOR_MAX; i++) { + + /* Check error reported */ + if (err_vec[i].error_reported) { + offset = ELM_LOCATION_STATUS + ERROR_LOCATION_SIZE * i; + reg_val = elm_read_reg(info, offset); + + /* Check correctable error or not */ + if (reg_val & ECC_CORRECTABLE_MASK) { + offset = ELM_ERROR_LOCATION_0 + + ERROR_LOCATION_SIZE * i; + + /* Read count of correctable errors */ + err_vec[i].error_count = reg_val & + ECC_NB_ERRORS_MASK; + + /* Update the error locations in error vector */ + for (j = 0; j < err_vec[i].error_count; j++) { + + reg_val = elm_read_reg(info, offset); + err_vec[i].error_loc[j] = reg_val & + ECC_ERROR_LOCATION_MASK; + + /* Update error location register */ + offset += 4; + } + + errors += err_vec[i].error_count; + } else { + err_vec[i].error_uncorrectable = true; + } + + /* Clearing interrupts for processed error vectors */ + elm_write_reg(info, ELM_IRQSTATUS, BIT(i)); + + /* Disable page mode */ + elm_configure_page_mode(info, i, false); + } + } +} + +/** + * elm_decode_bch_error_page - Locate error position + * @dev: device pointer + * @ecc_calc: calculated ECC bytes from GPMC + * @err_vec: elm error vectors + * + * Called with one or more error reported vectors & vectors with + * error reported is updated in err_vec[].error_reported + */ +void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc, + struct elm_errorvec *err_vec) +{ + struct elm_info *info = dev_get_drvdata(dev); + u32 reg_val; + + /* Enable page mode interrupt */ + reg_val = elm_read_reg(info, ELM_IRQSTATUS); + elm_write_reg(info, ELM_IRQSTATUS, reg_val & INTR_STATUS_PAGE_VALID); + elm_write_reg(info, ELM_IRQENABLE, INTR_EN_PAGE_MASK); + + /* Load valid ecc byte to syndrome fragment register */ + elm_load_syndrome(info, err_vec, ecc_calc); + + /* Enable syndrome processing for which syndrome fragment is updated */ + elm_start_processing(info, err_vec); + + /* Wait for ELM module to finish locating error correction */ + wait_for_completion(&info->elm_completion); + + /* Disable page mode interrupt */ + reg_val = elm_read_reg(info, ELM_IRQENABLE); + elm_write_reg(info, ELM_IRQENABLE, reg_val & ~INTR_EN_PAGE_MASK); + elm_error_correction(info, err_vec); +} +EXPORT_SYMBOL(elm_decode_bch_error_page); + +static irqreturn_t elm_isr(int this_irq, void *dev_id) +{ + u32 reg_val; + struct elm_info *info = dev_id; + + reg_val = elm_read_reg(info, ELM_IRQSTATUS); + + /* All error vectors processed */ + if (reg_val & INTR_STATUS_PAGE_VALID) { + elm_write_reg(info, ELM_IRQSTATUS, + reg_val & INTR_STATUS_PAGE_VALID); + complete(&info->elm_completion); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static int elm_probe(struct platform_device *pdev) +{ + int ret = 0; + struct resource *res, *irq; + struct elm_info *info; + + info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL); + if (!info) { + dev_err(&pdev->dev, "failed to allocate memory\n"); + return -ENOMEM; + } + + info->dev = &pdev->dev; + + irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); + if (!irq) { + dev_err(&pdev->dev, "no irq resource defined\n"); + return -ENODEV; + } + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pdev->dev, "no memory resource defined\n"); + return -ENODEV; + } + + info->elm_base = devm_request_and_ioremap(&pdev->dev, res); + if (!info->elm_base) + return -EADDRNOTAVAIL; + + ret = devm_request_irq(&pdev->dev, irq->start, elm_isr, 0, + pdev->name, info); + if (ret) { + dev_err(&pdev->dev, "failure requesting irq %i\n", irq->start); + return ret; + } + + pm_runtime_enable(&pdev->dev); + if (pm_runtime_get_sync(&pdev->dev)) { + ret = -EINVAL; + pm_runtime_disable(&pdev->dev); + dev_err(&pdev->dev, "can't enable clock\n"); + return ret; + } + + init_completion(&info->elm_completion); + INIT_LIST_HEAD(&info->list); + list_add(&info->list, &elm_devices); + platform_set_drvdata(pdev, info); + return ret; +} + +static int elm_remove(struct platform_device *pdev) +{ + pm_runtime_put_sync(&pdev->dev); + pm_runtime_disable(&pdev->dev); + platform_set_drvdata(pdev, NULL); + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id elm_of_match[] = { + { .compatible = "ti,am3352-elm" }, + {}, +}; +MODULE_DEVICE_TABLE(of, elm_of_match); +#endif + +static struct platform_driver elm_driver = { + .driver = { + .name = "elm", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(elm_of_match), + }, + .probe = elm_probe, + .remove = elm_remove, +}; + +module_platform_driver(elm_driver); + +MODULE_DESCRIPTION("ELM driver for BCH error correction"); +MODULE_AUTHOR("Texas Instruments"); +MODULE_ALIAS("platform: elm"); +MODULE_LICENSE("GPL v2"); |