[deliverable/linux.git] / drivers / mtd / devices / elm.c

/*
 * 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/sched.h>
#include <linux/pm_runtime.h>
#include <linux/platform_data/elm.h>

#define ELM_SYSCONFIG			0x010
#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_1		0x404
#define ELM_SYNDROME_FRAGMENT_2		0x408
#define ELM_SYNDROME_FRAGMENT_3		0x40c
#define ELM_SYNDROME_FRAGMENT_4		0x410
#define ELM_SYNDROME_FRAGMENT_5		0x414
#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_registers {
	u32 elm_irqenable;
	u32 elm_sysconfig;
	u32 elm_location_config;
	u32 elm_page_ctrl;
	u32 elm_syndrome_fragment_6[ERROR_VECTOR_MAX];
	u32 elm_syndrome_fragment_5[ERROR_VECTOR_MAX];
	u32 elm_syndrome_fragment_4[ERROR_VECTOR_MAX];
	u32 elm_syndrome_fragment_3[ERROR_VECTOR_MAX];
	u32 elm_syndrome_fragment_2[ERROR_VECTOR_MAX];
	u32 elm_syndrome_fragment_1[ERROR_VECTOR_MAX];
	u32 elm_syndrome_fragment_0[ERROR_VECTOR_MAX];
};

struct elm_info {
	struct device *dev;
	void __iomem *elm_base;
	struct completion elm_completion;
	struct list_head list;
	enum bch_ecc bch_type;
	struct elm_registers elm_regs;
};

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
 */
int elm_config(struct device *dev, enum bch_ecc bch_type)
{
	u32 reg_val;
	struct elm_info *info = dev_get_drvdata(dev);

	if (!info) {
		dev_err(dev, "Unable to configure elm - device not probed?\n");
		return -ENODEV;
	}

	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;

	return 0;
}
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);
	info->elm_base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(info->elm_base))
		return PTR_ERR(info->elm_base);

	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);
	return 0;
}

/**
 * elm_context_save
 * saves ELM configurations to preserve them across Hardware powered-down
 */
static int elm_context_save(struct elm_info *info)
{
	struct elm_registers *regs = &info->elm_regs;
	enum bch_ecc bch_type = info->bch_type;
	u32 offset = 0, i;

	regs->elm_irqenable       = elm_read_reg(info, ELM_IRQENABLE);
	regs->elm_sysconfig       = elm_read_reg(info, ELM_SYSCONFIG);
	regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG);
	regs->elm_page_ctrl       = elm_read_reg(info, ELM_PAGE_CTRL);
	for (i = 0; i < ERROR_VECTOR_MAX; i++) {
		offset = i * SYNDROME_FRAGMENT_REG_SIZE;
		switch (bch_type) {
		case BCH8_ECC:
			regs->elm_syndrome_fragment_3[i] = elm_read_reg(info,
					ELM_SYNDROME_FRAGMENT_3 + offset);
			regs->elm_syndrome_fragment_2[i] = elm_read_reg(info,
					ELM_SYNDROME_FRAGMENT_2 + offset);
		case BCH4_ECC:
			regs->elm_syndrome_fragment_1[i] = elm_read_reg(info,
					ELM_SYNDROME_FRAGMENT_1 + offset);
			regs->elm_syndrome_fragment_0[i] = elm_read_reg(info,
					ELM_SYNDROME_FRAGMENT_0 + offset);
		default:
			return -EINVAL;
		}
		/* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs
		 * to be saved for all BCH schemes*/
		regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
					ELM_SYNDROME_FRAGMENT_6 + offset);
	}
	return 0;
}

/**
 * elm_context_restore
 * writes configurations saved duing power-down back into ELM registers
 */
static int elm_context_restore(struct elm_info *info)
{
	struct elm_registers *regs = &info->elm_regs;
	enum bch_ecc bch_type = info->bch_type;
	u32 offset = 0, i;

	elm_write_reg(info, ELM_IRQENABLE,	 regs->elm_irqenable);
	elm_write_reg(info, ELM_SYSCONFIG,	 regs->elm_sysconfig);
	elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config);
	elm_write_reg(info, ELM_PAGE_CTRL,	 regs->elm_page_ctrl);
	for (i = 0; i < ERROR_VECTOR_MAX; i++) {
		offset = i * SYNDROME_FRAGMENT_REG_SIZE;
		switch (bch_type) {
		case BCH8_ECC:
			elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset,
					regs->elm_syndrome_fragment_3[i]);
			elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset,
					regs->elm_syndrome_fragment_2[i]);
		case BCH4_ECC:
			elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset,
					regs->elm_syndrome_fragment_1[i]);
			elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset,
					regs->elm_syndrome_fragment_0[i]);
		default:
			return -EINVAL;
		}
		/* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */
		elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
					regs->elm_syndrome_fragment_6[i] &
							 ELM_SYNDROME_VALID);
	}
	return 0;
}

static int elm_suspend(struct device *dev)
{
	struct elm_info *info = dev_get_drvdata(dev);
	elm_context_save(info);
	pm_runtime_put_sync(dev);
	return 0;
}

static int elm_resume(struct device *dev)
{
	struct elm_info *info = dev_get_drvdata(dev);
	pm_runtime_get_sync(dev);
	elm_context_restore(info);
	return 0;
}

static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);

#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),
		.pm	= &elm_pm_ops,
	},
	.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");
Commit	Line	Data
bf224335 PA	1	/*
	2	* Error Location Module
	3	*
	4	* Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	*/
	17
	18	#include <linux/platform_device.h>
	19	#include <linux/module.h>
	20	#include <linux/interrupt.h>
	21	#include <linux/io.h>
	22	#include <linux/of.h>
11f164d1	23	#include <linux/sched.h>
bf224335 PA	24	#include <linux/pm_runtime.h>
	25	#include <linux/platform_data/elm.h>
	26
11f164d1	27	#define ELM_SYSCONFIG 0x010
bf224335 PA	28	#define ELM_IRQSTATUS 0x018
	29	#define ELM_IRQENABLE 0x01c
	30	#define ELM_LOCATION_CONFIG 0x020
	31	#define ELM_PAGE_CTRL 0x080
	32	#define ELM_SYNDROME_FRAGMENT_0 0x400
11f164d1	33	#define ELM_SYNDROME_FRAGMENT_1 0x404
	34	#define ELM_SYNDROME_FRAGMENT_2 0x408
	35	#define ELM_SYNDROME_FRAGMENT_3 0x40c
	36	#define ELM_SYNDROME_FRAGMENT_4 0x410
	37	#define ELM_SYNDROME_FRAGMENT_5 0x414
bf224335 PA	38	#define ELM_SYNDROME_FRAGMENT_6 0x418
	39	#define ELM_LOCATION_STATUS 0x800
	40	#define ELM_ERROR_LOCATION_0 0x880
	41
	42	/* ELM Interrupt Status Register */
	43	#define INTR_STATUS_PAGE_VALID BIT(8)
	44
	45	/* ELM Interrupt Enable Register */
	46	#define INTR_EN_PAGE_MASK BIT(8)
	47
	48	/* ELM Location Configuration Register */
	49	#define ECC_BCH_LEVEL_MASK 0x3
	50
	51	/* ELM syndrome */
	52	#define ELM_SYNDROME_VALID BIT(16)
	53
	54	/* ELM_LOCATION_STATUS Register */
	55	#define ECC_CORRECTABLE_MASK BIT(8)
	56	#define ECC_NB_ERRORS_MASK 0x1f
	57
	58	/* ELM_ERROR_LOCATION_0-15 Registers */
	59	#define ECC_ERROR_LOCATION_MASK 0x1fff
	60
	61	#define ELM_ECC_SIZE 0x7ff
	62
	63	#define SYNDROME_FRAGMENT_REG_SIZE 0x40
	64	#define ERROR_LOCATION_SIZE 0x100
	65
11f164d1	66	struct elm_registers {
	67	u32 elm_irqenable;
	68	u32 elm_sysconfig;
	69	u32 elm_location_config;
	70	u32 elm_page_ctrl;
	71	u32 elm_syndrome_fragment_6[ERROR_VECTOR_MAX];
	72	u32 elm_syndrome_fragment_5[ERROR_VECTOR_MAX];
	73	u32 elm_syndrome_fragment_4[ERROR_VECTOR_MAX];
	74	u32 elm_syndrome_fragment_3[ERROR_VECTOR_MAX];
	75	u32 elm_syndrome_fragment_2[ERROR_VECTOR_MAX];
	76	u32 elm_syndrome_fragment_1[ERROR_VECTOR_MAX];
	77	u32 elm_syndrome_fragment_0[ERROR_VECTOR_MAX];
	78	};
	79
bf224335 PA	80	struct elm_info {
	81	struct device *dev;
	82	void __iomem *elm_base;
	83	struct completion elm_completion;
	84	struct list_head list;
	85	enum bch_ecc bch_type;
11f164d1	86	struct elm_registers elm_regs;
bf224335 PA	87	};
	88
	89	static LIST_HEAD(elm_devices);
	90
	91	static void elm_write_reg(struct elm_info *info, int offset, u32 val)
	92	{
	93	writel(val, info->elm_base + offset);
	94	}
	95
	96	static u32 elm_read_reg(struct elm_info *info, int offset)
	97	{
	98	return readl(info->elm_base + offset);
	99	}
	100
	101	/**
	102	* elm_config - Configure ELM module
	103	* @dev: ELM device
	104	* @bch_type: Type of BCH ecc
	105	*/
ad245789	106	int elm_config(struct device *dev, enum bch_ecc bch_type)
bf224335 PA	107	{
	108	u32 reg_val;
	109	struct elm_info *info = dev_get_drvdata(dev);
	110
ad245789 DM	111	if (!info) {
	112	dev_err(dev, "Unable to configure elm - device not probed?\n");
	113	return -ENODEV;
	114	}
	115
bf224335 PA	116	reg_val = (bch_type & ECC_BCH_LEVEL_MASK) \| (ELM_ECC_SIZE << 16);
	117	elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val);
	118	info->bch_type = bch_type;
ad245789 DM	119
ad245789 DM	120	return 0;
bf224335 PA	121	}
	122	EXPORT_SYMBOL(elm_config);
	123
	124	/**
	125	* elm_configure_page_mode - Enable/Disable page mode
	126	* @info: elm info
	127	* @index: index number of syndrome fragment vector
	128	* @enable: enable/disable flag for page mode
	129	*
	130	* Enable page mode for syndrome fragment index
	131	*/
	132	static void elm_configure_page_mode(struct elm_info *info, int index,
	133	bool enable)
	134	{
	135	u32 reg_val;
	136
	137	reg_val = elm_read_reg(info, ELM_PAGE_CTRL);
	138	if (enable)
	139	reg_val \|= BIT(index); /* enable page mode */
	140	else
	141	reg_val &= ~BIT(index); /* disable page mode */
	142
	143	elm_write_reg(info, ELM_PAGE_CTRL, reg_val);
	144	}
	145
	146	/**
	147	* elm_load_syndrome - Load ELM syndrome reg
	148	* @info: elm info
	149	* @err_vec: elm error vectors
	150	* @ecc: buffer with calculated ecc
	151	*
	152	* Load syndrome fragment registers with calculated ecc in reverse order.
	153	*/
	154	static void elm_load_syndrome(struct elm_info *info,
	155	struct elm_errorvec err_vec, u8 ecc)
	156	{
	157	int i, offset;
	158	u32 val;
	159
	160	for (i = 0; i < ERROR_VECTOR_MAX; i++) {
	161
	162	/* Check error reported */
	163	if (err_vec[i].error_reported) {
	164	elm_configure_page_mode(info, i, true);
	165	offset = ELM_SYNDROME_FRAGMENT_0 +
	166	SYNDROME_FRAGMENT_REG_SIZE * i;
	167
	168	/* BCH8 */
	169	if (info->bch_type) {
	170
	171	/* syndrome fragment 0 = ecc[9-12B] */
	172	val = cpu_to_be32((u32 ) &ecc[9]);
	173	elm_write_reg(info, offset, val);
	174
	175	/* syndrome fragment 1 = ecc[5-8B] */
	176	offset += 4;
	177	val = cpu_to_be32((u32 ) &ecc[5]);
	178	elm_write_reg(info, offset, val);
	179
	180	/* syndrome fragment 2 = ecc[1-4B] */
	181	offset += 4;
	182	val = cpu_to_be32((u32 ) &ecc[1]);
	183	elm_write_reg(info, offset, val);
	184
185	/* syndrome fragment 3 = ecc[0B] */
186	offset += 4;
187	val = ecc[0];
188	elm_write_reg(info, offset, val);
189	} else {
190	/* syndrome fragment 0 = ecc[20-52b] bits */
191	val = (cpu_to_be32((u32 ) &ecc[3]) >> 4) \|
192	((ecc[2] & 0xf) << 28);
193	elm_write_reg(info, offset, val);
194
195	/* syndrome fragment 1 = ecc[0-20b] bits */
196	offset += 4;
197	val = cpu_to_be32((u32 ) &ecc[0]) >> 12;
198	elm_write_reg(info, offset, val);
199	}
200	}
201
202	/* Update ecc pointer with ecc byte size */
203	ecc += info->bch_type ? BCH8_SIZE : BCH4_SIZE;
204	}
205	}
206
207	/**
208	* elm_start_processing - start elm syndrome processing
209	* @info: elm info
210	* @err_vec: elm error vectors
211	*
212	* Set syndrome valid bit for syndrome fragment registers for which
213	* elm syndrome fragment registers are loaded. This enables elm module
214	* to start processing syndrome vectors.
215	*/
216	static void elm_start_processing(struct elm_info *info,
217	struct elm_errorvec *err_vec)
218	{
219	int i, offset;
220	u32 reg_val;
221
222	/*
223	* Set syndrome vector valid, so that ELM module
224	* will process it for vectors error is reported
225	*/
226	for (i = 0; i < ERROR_VECTOR_MAX; i++) {
227	if (err_vec[i].error_reported) {
228	offset = ELM_SYNDROME_FRAGMENT_6 +
229	SYNDROME_FRAGMENT_REG_SIZE * i;
230	reg_val = elm_read_reg(info, offset);
231	reg_val \|= ELM_SYNDROME_VALID;
232	elm_write_reg(info, offset, reg_val);
233	}
234	}
235	}
236
237	/**
238	* elm_error_correction - locate correctable error position
239	* @info: elm info
240	* @err_vec: elm error vectors
241	*
242	* On completion of processing by elm module, error location status
243	* register updated with correctable/uncorrectable error information.
244	* In case of correctable errors, number of errors located from
245	* elm location status register & read the positions from
246	* elm error location register.
247	*/
248	static void elm_error_correction(struct elm_info *info,
249	struct elm_errorvec *err_vec)
250	{
251	int i, j, errors = 0;
252	int offset;
253	u32 reg_val;
254
255	for (i = 0; i < ERROR_VECTOR_MAX; i++) {
256
257	/* Check error reported */
258	if (err_vec[i].error_reported) {
259	offset = ELM_LOCATION_STATUS + ERROR_LOCATION_SIZE * i;
260	reg_val = elm_read_reg(info, offset);
261
262	/* Check correctable error or not */
263	if (reg_val & ECC_CORRECTABLE_MASK) {
264	offset = ELM_ERROR_LOCATION_0 +
265	ERROR_LOCATION_SIZE * i;
266
267	/* Read count of correctable errors */
268	err_vec[i].error_count = reg_val &
269	ECC_NB_ERRORS_MASK;
270
271	/* Update the error locations in error vector */
272	for (j = 0; j < err_vec[i].error_count; j++) {
273
274	reg_val = elm_read_reg(info, offset);
275	err_vec[i].error_loc[j] = reg_val &
276	ECC_ERROR_LOCATION_MASK;
277
278	/* Update error location register */
279	offset += 4;
280	}
281
282	errors += err_vec[i].error_count;
283	} else {
284	err_vec[i].error_uncorrectable = true;
285	}
286
287	/* Clearing interrupts for processed error vectors */
288	elm_write_reg(info, ELM_IRQSTATUS, BIT(i));
289
290	/* Disable page mode */
291	elm_configure_page_mode(info, i, false);
292	}
293	}
294	}
295
296	/**
297	* elm_decode_bch_error_page - Locate error position
298	* @dev: device pointer
299	* @ecc_calc: calculated ECC bytes from GPMC
300	* @err_vec: elm error vectors
301	*
302	* Called with one or more error reported vectors & vectors with
303	* error reported is updated in err_vec[].error_reported
304	*/
305	void elm_decode_bch_error_page(struct device dev, u8 ecc_calc,
306	struct elm_errorvec *err_vec)
307	{
308	struct elm_info *info = dev_get_drvdata(dev);
309	u32 reg_val;
310
311	/* Enable page mode interrupt */
312	reg_val = elm_read_reg(info, ELM_IRQSTATUS);
313	elm_write_reg(info, ELM_IRQSTATUS, reg_val & INTR_STATUS_PAGE_VALID);
314	elm_write_reg(info, ELM_IRQENABLE, INTR_EN_PAGE_MASK);
315
316	/* Load valid ecc byte to syndrome fragment register */
317	elm_load_syndrome(info, err_vec, ecc_calc);
318
319	/* Enable syndrome processing for which syndrome fragment is updated */
320	elm_start_processing(info, err_vec);
321
322	/* Wait for ELM module to finish locating error correction */
323	wait_for_completion(&info->elm_completion);
324
325	/* Disable page mode interrupt */
326	reg_val = elm_read_reg(info, ELM_IRQENABLE);
327	elm_write_reg(info, ELM_IRQENABLE, reg_val & ~INTR_EN_PAGE_MASK);
328	elm_error_correction(info, err_vec);
329	}
330	EXPORT_SYMBOL(elm_decode_bch_error_page);
331
332	static irqreturn_t elm_isr(int this_irq, void *dev_id)
333	{
334	u32 reg_val;
335	struct elm_info *info = dev_id;
336
337	reg_val = elm_read_reg(info, ELM_IRQSTATUS);
338
339	/* All error vectors processed */
340	if (reg_val & INTR_STATUS_PAGE_VALID) {
341	elm_write_reg(info, ELM_IRQSTATUS,
342	reg_val & INTR_STATUS_PAGE_VALID);
343	complete(&info->elm_completion);
344	return IRQ_HANDLED;
345	}
346
347	return IRQ_NONE;
348	}
349
350	static int elm_probe(struct platform_device *pdev)
351	{
352	int ret = 0;
353	struct resource res, irq;
354	struct elm_info *info;
355
356	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
357	if (!info) {
358	dev_err(&pdev->dev, "failed to allocate memory\n");
359	return -ENOMEM;
360	}
361
362	info->dev = &pdev->dev;
363
364	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
365	if (!irq) {
366	dev_err(&pdev->dev, "no irq resource defined\n");
367	return -ENODEV;
368	}
369
370	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
43579688 SMP	371	info->elm_base = devm_ioremap_resource(&pdev->dev, res);
	372	if (IS_ERR(info->elm_base))
	373	return PTR_ERR(info->elm_base);
bf224335 PA	374
	375	ret = devm_request_irq(&pdev->dev, irq->start, elm_isr, 0,
	376	pdev->name, info);
	377	if (ret) {
	378	dev_err(&pdev->dev, "failure requesting irq %i\n", irq->start);
	379	return ret;
	380	}
	381
	382	pm_runtime_enable(&pdev->dev);
	383	if (pm_runtime_get_sync(&pdev->dev)) {
	384	ret = -EINVAL;
	385	pm_runtime_disable(&pdev->dev);
	386	dev_err(&pdev->dev, "can't enable clock\n");
	387	return ret;
	388	}
	389
	390	init_completion(&info->elm_completion);
	391	INIT_LIST_HEAD(&info->list);
	392	list_add(&info->list, &elm_devices);
	393	platform_set_drvdata(pdev, info);
	394	return ret;
	395	}
	396
	397	static int elm_remove(struct platform_device *pdev)
	398	{
	399	pm_runtime_put_sync(&pdev->dev);
	400	pm_runtime_disable(&pdev->dev);
bf224335 PA	401	return 0;
	402	}
	403
11f164d1	404	/**
	405	* elm_context_save
	406	* saves ELM configurations to preserve them across Hardware powered-down
	407	*/
	408	static int elm_context_save(struct elm_info *info)
	409	{
	410	struct elm_registers *regs = &info->elm_regs;
	411	enum bch_ecc bch_type = info->bch_type;
	412	u32 offset = 0, i;
	413
	414	regs->elm_irqenable = elm_read_reg(info, ELM_IRQENABLE);
	415	regs->elm_sysconfig = elm_read_reg(info, ELM_SYSCONFIG);
	416	regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG);
	417	regs->elm_page_ctrl = elm_read_reg(info, ELM_PAGE_CTRL);
	418	for (i = 0; i < ERROR_VECTOR_MAX; i++) {
	419	offset = i * SYNDROME_FRAGMENT_REG_SIZE;
	420	switch (bch_type) {
	421	case BCH8_ECC:
	422	regs->elm_syndrome_fragment_3[i] = elm_read_reg(info,
	423	ELM_SYNDROME_FRAGMENT_3 + offset);
	424	regs->elm_syndrome_fragment_2[i] = elm_read_reg(info,
	425	ELM_SYNDROME_FRAGMENT_2 + offset);
	426	case BCH4_ECC:
	427	regs->elm_syndrome_fragment_1[i] = elm_read_reg(info,
	428	ELM_SYNDROME_FRAGMENT_1 + offset);
	429	regs->elm_syndrome_fragment_0[i] = elm_read_reg(info,
	430	ELM_SYNDROME_FRAGMENT_0 + offset);
	431	default:
	432	return -EINVAL;
	433	}
	434	/* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs
	435	* to be saved for all BCH schemes*/
	436	regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
	437	ELM_SYNDROME_FRAGMENT_6 + offset);
	438	}
	439	return 0;
	440	}
	441
	442	/**
	443	* elm_context_restore
	444	* writes configurations saved duing power-down back into ELM registers
	445	*/
	446	static int elm_context_restore(struct elm_info *info)
	447	{
	448	struct elm_registers *regs = &info->elm_regs;
	449	enum bch_ecc bch_type = info->bch_type;
	450	u32 offset = 0, i;
	451
	452	elm_write_reg(info, ELM_IRQENABLE, regs->elm_irqenable);
	453	elm_write_reg(info, ELM_SYSCONFIG, regs->elm_sysconfig);
	454	elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config);
	455	elm_write_reg(info, ELM_PAGE_CTRL, regs->elm_page_ctrl);
	456	for (i = 0; i < ERROR_VECTOR_MAX; i++) {
	457	offset = i * SYNDROME_FRAGMENT_REG_SIZE;
	458	switch (bch_type) {
	459	case BCH8_ECC:
	460	elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset,
	461	regs->elm_syndrome_fragment_3[i]);
	462	elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset,
	463	regs->elm_syndrome_fragment_2[i]);
	464	case BCH4_ECC:
	465	elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset,
	466	regs->elm_syndrome_fragment_1[i]);
	467	elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset,
468	regs->elm_syndrome_fragment_0[i]);
469	default:
470	return -EINVAL;
471	}
472	/* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */
473	elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
474	regs->elm_syndrome_fragment_6[i] &
475	ELM_SYNDROME_VALID);
476	}
477	return 0;
478	}
479
480	static int elm_suspend(struct device *dev)
481	{
482	struct elm_info *info = dev_get_drvdata(dev);
483	elm_context_save(info);
484	pm_runtime_put_sync(dev);
485	return 0;
486	}
487
488	static int elm_resume(struct device *dev)
489	{
490	struct elm_info *info = dev_get_drvdata(dev);
491	pm_runtime_get_sync(dev);
492	elm_context_restore(info);
493	return 0;
494	}
495
496	static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);
497
bf224335 PA	498	#ifdef CONFIG_OF
bf224335 PA	499	static const struct of_device_id elm_of_match[] = {
c80e572c	500	{ .compatible = "ti,am3352-elm" },
bf224335 PA	501	{},
	502	};
	503	MODULE_DEVICE_TABLE(of, elm_of_match);
	504	#endif
	505
	506	static struct platform_driver elm_driver = {
	507	.driver = {
	508	.name = "elm",
	509	.owner = THIS_MODULE,
	510	.of_match_table = of_match_ptr(elm_of_match),
11f164d1	511	.pm = &elm_pm_ops,
bf224335 PA	512	},
	513	.probe = elm_probe,
	514	.remove = elm_remove,
	515	};
	516
	517	module_platform_driver(elm_driver);
	518
	519	MODULE_DESCRIPTION("ELM driver for BCH error correction");
	520	MODULE_AUTHOR("Texas Instruments");
	521	MODULE_ALIAS("platform: elm");
	522	MODULE_LICENSE("GPL v2");