/*
 * Synopsys DDR ECC Driver
 * This driver is based on ppc4xx_edac.c drivers
 *
 * Copyright (C) 2012 - 2014 Xilinx, Inc.
 *
 * 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.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details
 */

#include <linux/edac.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_device.h>

#include "edac_module.h"

/* Number of cs_rows needed per memory controller */
#define SYNPS_EDAC_NR_CSROWS		1

/* Number of channels per memory controller */
#define SYNPS_EDAC_NR_CHANS		1

/* Granularity of reported error in bytes */
#define SYNPS_EDAC_ERR_GRAIN		1

#define SYNPS_EDAC_MSG_SIZE		256

#define SYNPS_EDAC_MOD_STRING		"synps_edac"
#define SYNPS_EDAC_MOD_VER		"1"

/* Synopsys DDR memory controller registers that are relevant to ECC */
#define CTRL_OFST			0x0
#define T_ZQ_OFST			0xA4

/* ECC control register */
#define ECC_CTRL_OFST			0xC4
/* ECC log register */
#define CE_LOG_OFST			0xC8
/* ECC address register */
#define CE_ADDR_OFST			0xCC
/* ECC data[31:0] register */
#define CE_DATA_31_0_OFST		0xD0

/* Uncorrectable error info registers */
#define UE_LOG_OFST			0xDC
#define UE_ADDR_OFST			0xE0
#define UE_DATA_31_0_OFST		0xE4

#define STAT_OFST			0xF0
#define SCRUB_OFST			0xF4

/* Control register bit field definitions */
#define CTRL_BW_MASK			0xC
#define CTRL_BW_SHIFT			2

#define DDRCTL_WDTH_16			1
#define DDRCTL_WDTH_32			0

/* ZQ register bit field definitions */
#define T_ZQ_DDRMODE_MASK		0x2

/* ECC control register bit field definitions */
#define ECC_CTRL_CLR_CE_ERR		0x2
#define ECC_CTRL_CLR_UE_ERR		0x1

/* ECC correctable/uncorrectable error log register definitions */
#define LOG_VALID			0x1
#define CE_LOG_BITPOS_MASK		0xFE
#define CE_LOG_BITPOS_SHIFT		1

/* ECC correctable/uncorrectable error address register definitions */
#define ADDR_COL_MASK			0xFFF
#define ADDR_ROW_MASK			0xFFFF000
#define ADDR_ROW_SHIFT			12
#define ADDR_BANK_MASK			0x70000000
#define ADDR_BANK_SHIFT			28

/* ECC statistic register definitions */
#define STAT_UECNT_MASK			0xFF
#define STAT_CECNT_MASK			0xFF00
#define STAT_CECNT_SHIFT		8

/* ECC scrub register definitions */
#define SCRUB_MODE_MASK			0x7
#define SCRUB_MODE_SECDED		0x4

/**
 * struct ecc_error_info - ECC error log information.
 * @row:	Row number.
 * @col:	Column number.
 * @bank:	Bank number.
 * @bitpos:	Bit position.
 * @data:	Data causing the error.
 */
struct ecc_error_info {
	u32 row;
	u32 col;
	u32 bank;
	u32 bitpos;
	u32 data;
};

/**
 * struct synps_ecc_status - ECC status information to report.
 * @ce_cnt:	Correctable error count.
 * @ue_cnt:	Uncorrectable error count.
 * @ceinfo:	Correctable error log information.
 * @ueinfo:	Uncorrectable error log information.
 */
struct synps_ecc_status {
	u32 ce_cnt;
	u32 ue_cnt;
	struct ecc_error_info ceinfo;
	struct ecc_error_info ueinfo;
};

/**
 * struct synps_edac_priv - DDR memory controller private instance data.
 * @baseaddr:	Base address of the DDR controller.
 * @message:	Buffer for framing the event specific info.
 * @stat:	ECC status information.
 * @p_data:	Platform data.
 * @ce_cnt:	Correctable Error count.
 * @ue_cnt:	Uncorrectable Error count.
 */
struct synps_edac_priv {
	void __iomem *baseaddr;
	char message[SYNPS_EDAC_MSG_SIZE];
	struct synps_ecc_status stat;
	const struct synps_platform_data *p_data;
	u32 ce_cnt;
	u32 ue_cnt;
};

/**
 * struct synps_platform_data -  synps platform data structure.
 * @get_error_info:	Get EDAC error info.
 * @get_mtype:		Get mtype.
 * @get_dtype:		Get dtype.
 * @get_ecc_state:	Get ECC state.
 * @quirks:		To differentiate IPs.
 */
struct synps_platform_data {
	int (*get_error_info)(struct synps_edac_priv *priv);
	enum mem_type (*get_mtype)(const void __iomem *base);
	enum dev_type (*get_dtype)(const void __iomem *base);
	bool (*get_ecc_state)(void __iomem *base);
	int quirks;
};

/**
 * zynq_get_error_info - Get the current ECC error info.
 * @priv:	DDR memory controller private instance data.
 *
 * Return: one if there is no error, otherwise zero.
 */
static int zynq_get_error_info(struct synps_edac_priv *priv)
{
	struct synps_ecc_status *p;
	u32 regval, clearval = 0;
	void __iomem *base;

	base = priv->baseaddr;
	p = &priv->stat;

	regval = readl(base + STAT_OFST);
	if (!regval)
		return 1;

	p->ce_cnt = (regval & STAT_CECNT_MASK) >> STAT_CECNT_SHIFT;
	p->ue_cnt = regval & STAT_UECNT_MASK;

	regval = readl(base + CE_LOG_OFST);
	if (!(p->ce_cnt && (regval & LOG_VALID)))
		goto ue_err;

	p->ceinfo.bitpos = (regval & CE_LOG_BITPOS_MASK) >> CE_LOG_BITPOS_SHIFT;
	regval = readl(base + CE_ADDR_OFST);
	p->ceinfo.row = (regval & ADDR_ROW_MASK) >> ADDR_ROW_SHIFT;
	p->ceinfo.col = regval & ADDR_COL_MASK;
	p->ceinfo.bank = (regval & ADDR_BANK_MASK) >> ADDR_BANK_SHIFT;
	p->ceinfo.data = readl(base + CE_DATA_31_0_OFST);
	edac_dbg(3, "CE bit position: %d data: %d\n", p->ceinfo.bitpos,
		 p->ceinfo.data);
	clearval = ECC_CTRL_CLR_CE_ERR;

ue_err:
	regval = readl(base + UE_LOG_OFST);
	if (!(p->ue_cnt && (regval & LOG_VALID)))
		goto out;

	regval = readl(base + UE_ADDR_OFST);
	p->ueinfo.row = (regval & ADDR_ROW_MASK) >> ADDR_ROW_SHIFT;
	p->ueinfo.col = regval & ADDR_COL_MASK;
	p->ueinfo.bank = (regval & ADDR_BANK_MASK) >> ADDR_BANK_SHIFT;
	p->ueinfo.data = readl(base + UE_DATA_31_0_OFST);
	clearval |= ECC_CTRL_CLR_UE_ERR;

out:
	writel(clearval, base + ECC_CTRL_OFST);
	writel(0x0, base + ECC_CTRL_OFST);

	return 0;
}

/**
 * handle_error - Handle Correctable and Uncorrectable errors.
 * @mci:	EDAC memory controller instance.
 * @p:		Synopsys ECC status structure.
 *
 * Handles ECC correctable and uncorrectable errors.
 */
static void handle_error(struct mem_ctl_info *mci, struct synps_ecc_status *p)
{
	struct synps_edac_priv *priv = mci->pvt_info;
	struct ecc_error_info *pinf;

	if (p->ce_cnt) {
		pinf = &p->ceinfo;
		snprintf(priv->message, SYNPS_EDAC_MSG_SIZE,
			 "DDR ECC error type :%s Row %d Bank %d Col %d ",
			 "CE", pinf->row, pinf->bank, pinf->col);
		edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci,
				     p->ce_cnt, 0, 0, 0, 0, 0, -1,
				     priv->message, "");
	}

	if (p->ue_cnt) {
		pinf = &p->ueinfo;
		snprintf(priv->message, SYNPS_EDAC_MSG_SIZE,
			 "DDR ECC error type :%s Row %d Bank %d Col %d ",
			 "UE", pinf->row, pinf->bank, pinf->col);
		edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci,
				     p->ue_cnt, 0, 0, 0, 0, 0, -1,
				     priv->message, "");
	}

	memset(p, 0, sizeof(*p));
}

/**
 * check_errors - Check controller for ECC errors.
 * @mci:	EDAC memory controller instance.
 *
 * Check and post ECC errors. Called by the polling thread.
 */
static void check_errors(struct mem_ctl_info *mci)
{
	struct synps_edac_priv *priv = mci->pvt_info;
	const struct synps_platform_data *p_data = priv->p_data;
	int status;

	status = p_data->get_error_info(priv);
	if (status)
		return;

	priv->ce_cnt += priv->stat.ce_cnt;
	priv->ue_cnt += priv->stat.ue_cnt;
	handle_error(mci, &priv->stat);

	edac_dbg(3, "Total error count CE %d UE %d\n",
		 priv->ce_cnt, priv->ue_cnt);
}

/**
 * zynq_get_dtype - Return the controller memory width.
 * @base:	DDR memory controller base address.
 *
 * Get the EDAC device type width appropriate for the current controller
 * configuration.
 *
 * Return: a device type width enumeration.
 */
static enum dev_type zynq_get_dtype(const void __iomem *base)
{
	enum dev_type dt;
	u32 width;

	width = readl(base + CTRL_OFST);
	width = (width & CTRL_BW_MASK) >> CTRL_BW_SHIFT;

	switch (width) {
	case DDRCTL_WDTH_16:
		dt = DEV_X2;
		break;
	case DDRCTL_WDTH_32:
		dt = DEV_X4;
		break;
	default:
		dt = DEV_UNKNOWN;
	}

	return dt;
}

/**
 * zynq_get_ecc_state - Return the controller ECC enable/disable status.
 * @base:	DDR memory controller base address.
 *
 * Get the ECC enable/disable status of the controller.
 *
 * Return: true if enabled, otherwise false.
 */
static bool zynq_get_ecc_state(void __iomem *base)
{
	bool state = false;
	enum dev_type dt;
	u32 ecctype;

	dt = zynq_get_dtype(base);
	if (dt == DEV_UNKNOWN)
		return state;

	ecctype = readl(base + SCRUB_OFST) & SCRUB_MODE_MASK;
	if ((ecctype == SCRUB_MODE_SECDED) && (dt == DEV_X2))
		state = true;

	return state;
}

/**
 * get_memsize - Read the size of the attached memory device.
 *
 * Return: the memory size in bytes.
 */
static u32 get_memsize(void)
{
	struct sysinfo inf;

	si_meminfo(&inf);

	return inf.totalram * inf.mem_unit;
}

/**
 * zynq_get_mtype - Return the controller memory type.
 * @base:	Synopsys ECC status structure.
 *
 * Get the EDAC memory type appropriate for the current controller
 * configuration.
 *
 * Return: a memory type enumeration.
 */
static enum mem_type zynq_get_mtype(const void __iomem *base)
{
	enum mem_type mt;
	u32 memtype;

	memtype = readl(base + T_ZQ_OFST);

	if (memtype & T_ZQ_DDRMODE_MASK)
		mt = MEM_DDR3;
	else
		mt = MEM_DDR2;

	return mt;
}

/**
 * init_csrows - Initialize the csrow data.
 * @mci:	EDAC memory controller instance.
 *
 * Initialize the chip select rows associated with the EDAC memory
 * controller instance.
 */
static void init_csrows(struct mem_ctl_info *mci)
{
	struct synps_edac_priv *priv = mci->pvt_info;
	const struct synps_platform_data *p_data;
	struct csrow_info *csi;
	struct dimm_info *dimm;
	u32 size, row;
	int j;

	p_data = priv->p_data;

	for (row = 0; row < mci->nr_csrows; row++) {
		csi = mci->csrows[row];
		size = get_memsize();

		for (j = 0; j < csi->nr_channels; j++) {
			dimm		= csi->channels[j]->dimm;
			dimm->edac_mode	= EDAC_FLAG_SECDED;
			dimm->mtype	= p_data->get_mtype(priv->baseaddr);
			dimm->nr_pages	= (size >> PAGE_SHIFT) / csi->nr_channels;
			dimm->grain	= SYNPS_EDAC_ERR_GRAIN;
			dimm->dtype	= p_data->get_dtype(priv->baseaddr);
		}
	}
}

/**
 * mc_init - Initialize one driver instance.
 * @mci:	EDAC memory controller instance.
 * @pdev:	platform device.
 *
 * Perform initialization of the EDAC memory controller instance and
 * related driver-private data associated with the memory controller the
 * instance is bound to.
 */
static void mc_init(struct mem_ctl_info *mci, struct platform_device *pdev)
{
	struct synps_edac_priv *priv;

	mci->pdev = &pdev->dev;
	priv = mci->pvt_info;
	platform_set_drvdata(pdev, mci);

	/* Initialize controller capabilities and configuration */
	mci->mtype_cap = MEM_FLAG_DDR3 | MEM_FLAG_DDR2;
	mci->edac_ctl_cap = EDAC_FLAG_NONE | EDAC_FLAG_SECDED;
	mci->scrub_cap = SCRUB_HW_SRC;
	mci->scrub_mode = SCRUB_NONE;

	mci->edac_cap = EDAC_FLAG_SECDED;
	mci->ctl_name = "synps_ddr_controller";
	mci->dev_name = SYNPS_EDAC_MOD_STRING;
	mci->mod_name = SYNPS_EDAC_MOD_VER;

	edac_op_state = EDAC_OPSTATE_POLL;
	mci->edac_check = check_errors;
	mci->ctl_page_to_phys = NULL;

	init_csrows(mci);
}

static const struct synps_platform_data zynq_edac_def = {
	.get_error_info	= zynq_get_error_info,
	.get_mtype	= zynq_get_mtype,
	.get_dtype	= zynq_get_dtype,
	.get_ecc_state	= zynq_get_ecc_state,
	.quirks		= 0,
};

static const struct of_device_id synps_edac_match[] = {
	{ .compatible = "xlnx,zynq-ddrc-a05", .data = (void *)&zynq_edac_def },
	{ /* end of table */ }
};

MODULE_DEVICE_TABLE(of, synps_edac_match);

/**
 * mc_probe - Check controller and bind driver.
 * @pdev:	platform device.
 *
 * Probe a specific controller instance for binding with the driver.
 *
 * Return: 0 if the controller instance was successfully bound to the
 * driver; otherwise, < 0 on error.
 */
static int mc_probe(struct platform_device *pdev)
{
	const struct synps_platform_data *p_data;
	struct edac_mc_layer layers[2];
	struct synps_edac_priv *priv;
	struct mem_ctl_info *mci;
	void __iomem *baseaddr;
	struct resource *res;
	int rc;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	baseaddr = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(baseaddr))
		return PTR_ERR(baseaddr);

	p_data = of_device_get_match_data(&pdev->dev);
	if (!p_data)
		return -ENODEV;

	if (!p_data->get_ecc_state(baseaddr)) {
		edac_printk(KERN_INFO, EDAC_MC, "ECC not enabled\n");
		return -ENXIO;
	}

	layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
	layers[0].size = SYNPS_EDAC_NR_CSROWS;
	layers[0].is_virt_csrow = true;
	layers[1].type = EDAC_MC_LAYER_CHANNEL;
	layers[1].size = SYNPS_EDAC_NR_CHANS;
	layers[1].is_virt_csrow = false;

	mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers,
			    sizeof(struct synps_edac_priv));
	if (!mci) {
		edac_printk(KERN_ERR, EDAC_MC,
			    "Failed memory allocation for mc instance\n");
		return -ENOMEM;
	}

	priv = mci->pvt_info;
	priv->baseaddr = baseaddr;
	priv->p_data = p_data;

	mc_init(mci, pdev);

	rc = edac_mc_add_mc(mci);
	if (rc) {
		edac_printk(KERN_ERR, EDAC_MC,
			    "Failed to register with EDAC core\n");
		goto free_edac_mc;
	}

	/*
	 * Start capturing the correctable and uncorrectable errors. A write of
	 * 0 starts the counters.
	 */
	writel(0x0, baseaddr + ECC_CTRL_OFST);
	return rc;

free_edac_mc:
	edac_mc_free(mci);

	return rc;
}

/**
 * mc_remove - Unbind driver from controller.
 * @pdev:	Platform device.
 *
 * Return: Unconditionally 0
 */
static int mc_remove(struct platform_device *pdev)
{
	struct mem_ctl_info *mci = platform_get_drvdata(pdev);

	edac_mc_del_mc(&pdev->dev);
	edac_mc_free(mci);

	return 0;
}

static struct platform_driver synps_edac_mc_driver = {
	.driver = {
		   .name = "synopsys-edac",
		   .of_match_table = synps_edac_match,
		   },
	.probe = mc_probe,
	.remove = mc_remove,
};

module_platform_driver(synps_edac_mc_driver);

MODULE_AUTHOR("Xilinx Inc");
MODULE_DESCRIPTION("Synopsys DDR ECC driver");
MODULE_LICENSE("GPL v2");