// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2019 Quanta Computer lnc.
 */

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

#include "edac_module.h"

#define ECC_ENABLE                     BIT(24)
#define ECC_EN_INT_MASK                0x7fffff87

#define INT_STATUS_ADDR                116
#define INT_ACK_ADDR                   117
#define INT_MASK_ADDR                  118

#define ECC_EN_ADDR                    93
#define ECC_C_ADDR_ADDR                98
#define ECC_C_DATA_ADDR                100
#define ECC_C_ID_ADDR                  101
#define ECC_C_SYND_ADDR                99
#define ECC_U_ADDR_ADDR                95
#define ECC_U_DATA_ADDR                97
#define ECC_U_ID_ADDR                  101
#define ECC_U_SYND_ADDR                96

#define ECC_ERROR                      -1
#define EDAC_MSG_SIZE                  256
#define EDAC_MOD_NAME                  "npcm7xx-edac"

struct ecc_error_signature_info {
	u32 ecc_addr;
	u32 ecc_data;
	u32 ecc_id;
	u32 ecc_synd;
};

struct npcm7xx_ecc_int_status {
	u32 int_mask;
	u32 int_status;
	u32 int_ack;
	u32 ce_cnt;
	u32 ue_cnt;
	struct ecc_error_signature_info ceinfo;
	struct ecc_error_signature_info ueinfo;
};

struct npcm7xx_edac_priv {
	void __iomem *baseaddr;
	char message[EDAC_MSG_SIZE];
	struct npcm7xx_ecc_int_status stat;
};

/**
 * npcm7xx_edac_get_ecc_syndrom - Get the current ecc error info
 * @base:	Pointer to the base address of the ddr memory controller
 * @p:		Pointer to the Nuvoton ecc status structure
 *
 * Determines there is any ecc error or not
 *
 * Return: ECC detection status
 */
static int npcm7xx_edac_get_ecc_syndrom(void __iomem *base,
					struct npcm7xx_ecc_int_status *p)
{
	int status = 0;
	u32 int_status = 0;

	int_status = readl(base + 4*INT_STATUS_ADDR);
	writel(int_status, base + 4*INT_ACK_ADDR);
	edac_dbg(3, "int_status: %#08x\n", int_status);

	if ((int_status & (1 << 6)) == (1 << 6)) {
		edac_dbg(3, "6-Mult uncorrectable detected.\n");
		p->ue_cnt++;
		status = ECC_ERROR;
	}

	if ((int_status & (1 << 5)) == (1 << 5)) {
		edac_dbg(3, "5-An uncorrectable detected\n");
		p->ue_cnt++;
		status = ECC_ERROR;
	}

	if ((int_status & (1 << 4)) == (1 << 4)) {
		edac_dbg(3, "4-mult correctable detected.\n");
		p->ce_cnt++;
		status = ECC_ERROR;
	}

	if ((int_status & (1 << 3)) == (1 << 3)) {
		edac_dbg(3, "3-A correctable detected.\n");
		p->ce_cnt++;
		status = ECC_ERROR;
	}

	if (status == ECC_ERROR) {
		u32 ecc_id;

		p->ceinfo.ecc_addr = readl(base + 4*ECC_C_ADDR_ADDR);
		p->ceinfo.ecc_data = readl(base + 4*ECC_C_DATA_ADDR);
		p->ceinfo.ecc_synd = readl(base + 4*ECC_C_SYND_ADDR);

		p->ueinfo.ecc_addr = readl(base + 4*ECC_U_ADDR_ADDR);
		p->ueinfo.ecc_data = readl(base + 4*ECC_U_DATA_ADDR);
		p->ueinfo.ecc_synd = readl(base + 4*ECC_U_SYND_ADDR);

		/* ECC_C_ID_ADDR has same value as ECC_U_ID_ADDR */
		ecc_id = readl(base + 4*ECC_C_ID_ADDR);
		p->ueinfo.ecc_id = ecc_id & 0xffff;
		p->ceinfo.ecc_id = ecc_id >> 16;
	}

	return status;
}

/**
 * npcm7xx_edac_handle_error - Handle controller error types CE and UE
 * @mci:	Pointer to the edac memory controller instance
 * @p:		Pointer to the Nuvoton ecc status structure
 *
 * Handles the controller ECC correctable and un correctable error.
 */
static void npcm7xx_edac_handle_error(struct mem_ctl_info *mci,
				    struct npcm7xx_ecc_int_status *p)
{
	struct npcm7xx_edac_priv *priv = mci->pvt_info;
	u32 page, offset;

	if (p->ce_cnt) {
		snprintf(priv->message, EDAC_MSG_SIZE,
			"DDR ECC: synd=%#08x addr=%#08x data=%#08x source_id=%#08x ",
			p->ceinfo.ecc_synd, p->ceinfo.ecc_addr,
			p->ceinfo.ecc_data, p->ceinfo.ecc_id);

		page = p->ceinfo.ecc_addr >> PAGE_SHIFT;
		offset = p->ceinfo.ecc_addr & ~PAGE_MASK;
		edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci,
				     p->ce_cnt, page, offset,
				     p->ceinfo.ecc_synd,
				     0, 0, -1,
				     priv->message, "");
	}

	if (p->ue_cnt) {
		snprintf(priv->message, EDAC_MSG_SIZE,
			"DDR ECC: synd=%#08x addr=%#08x data=%#08x source_id=%#08x ",
			p->ueinfo.ecc_synd, p->ueinfo.ecc_addr,
			p->ueinfo.ecc_data, p->ueinfo.ecc_id);

		page = p->ueinfo.ecc_addr >> PAGE_SHIFT;
		offset = p->ueinfo.ecc_addr & ~PAGE_MASK;
		edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci,
				     p->ue_cnt, page, offset,
				     p->ueinfo.ecc_synd,
				     0, 0, -1,
				     priv->message, "");
	}

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

/**
 * npcm7xx_edac_check - Check controller for ECC errors
 * @mci:	Pointer to the edac memory controller instance
 *
 * This routine is used to check and post ECC errors and is called by
 * this driver's CE and UE interrupt handler.
 */
static void npcm7xx_edac_check(struct mem_ctl_info *mci)
{
	struct npcm7xx_edac_priv *priv = mci->pvt_info;
	int status = 0;

	status = npcm7xx_edac_get_ecc_syndrom(priv->baseaddr, &priv->stat);
	if (status != ECC_ERROR)
		return;

	npcm7xx_edac_handle_error(mci, &priv->stat);
}

/**
 * npcm7xx_edac_isr - CE/UE interrupt service routine
 * @irq:    The virtual interrupt number being serviced.
 * @dev_id: A pointer to the EDAC memory controller instance
 *          associated with the interrupt being handled.
 *
 * This routine implements the interrupt handler for both correctable
 * (CE) and uncorrectable (UE) ECC errors for the Nuvoton Cadence DDR
 * controller. It simply calls through to the routine used to check,
 * report and clear the ECC status.
 *
 * Unconditionally returns IRQ_HANDLED.
 */
static irqreturn_t npcm7xx_edac_isr(int irq, void *dev_id)
{
	struct mem_ctl_info *mci = dev_id;

	npcm7xx_edac_check(mci);

	return IRQ_HANDLED;
}

static int npcm7xx_edac_register_irq(struct mem_ctl_info *mci,
					struct platform_device *pdev)
{
	int status = 0;
	int mc_irq;
	struct npcm7xx_edac_priv *priv = mci->pvt_info;

	/* Only enable MC interrupts with ECC - clear int_mask[6:3] */
	writel(ECC_EN_INT_MASK, priv->baseaddr + 4*INT_MASK_ADDR);

	mc_irq = platform_get_irq(pdev, 0);

	if (!mc_irq) {
		edac_printk(KERN_ERR, EDAC_MC, "Unable to map interrupts.\n");
		status = -ENODEV;
		goto fail;
	}

	status = devm_request_irq(&pdev->dev, mc_irq, npcm7xx_edac_isr, 0,
			       "npcm-memory-controller", mci);

	if (status < 0) {
		edac_printk(KERN_ERR, EDAC_MC,
				      "Unable to request irq %d for ECC",
				      mc_irq);
		status = -ENODEV;
		goto fail;
	}

	return 0;

fail:
	return status;
}

static const struct of_device_id npcm7xx_edac_of_match[] = {
	{ .compatible = "nuvoton,npcm7xx-sdram-edac"},
	{ /* end of table */ }
};

MODULE_DEVICE_TABLE(of, npcm7xx_edac_of_match);

/**
 * npcm7xx_edac_mc_init - Initialize driver instance
 * @mci:	Pointer to the edac memory controller instance
 * @pdev:	Pointer to the platform_device struct
 *
 * Performs initialization of the EDAC memory controller instance and
 * related driver-private data associated with the memory controller the
 * instance is bound to.
 *
 * Returns 0 if OK; otherwise, < 0 on error.
 */
static int npcm7xx_edac_mc_init(struct mem_ctl_info *mci,
				 struct platform_device *pdev)
{
	const struct of_device_id *id;

	id = of_match_device(npcm7xx_edac_of_match, &pdev->dev);
	if (!id)
		return -ENODEV;

	/* Initialize controller capabilities and configuration */
	mci->mtype_cap = MEM_FLAG_DDR4;
	mci->edac_ctl_cap = EDAC_FLAG_SECDED;
	mci->edac_cap = EDAC_FLAG_SECDED;
	mci->scrub_cap = SCRUB_FLAG_HW_SRC;
	mci->scrub_mode = SCRUB_HW_SRC;
	mci->ctl_name = id->compatible;
	mci->dev_name = dev_name(&pdev->dev);
	mci->mod_name = EDAC_MOD_NAME;

	edac_op_state = EDAC_OPSTATE_INT;

	return 0;
}

/**
 * npcm7xx_edac_get_eccstate - Return the controller ecc enable/disable status
 * @base:	Pointer to the ddr memory controller base address
 *
 * Get the ECC enable/disable status for the controller
 *
 * Return: a ecc status boolean i.e true/false - enabled/disabled.
 */
static bool npcm7xx_edac_get_eccstate(void __iomem *base)
{
	u32 ecc_en;
	bool state = false;

	ecc_en = readl(base + 4*ECC_EN_ADDR);
	if (ecc_en & ECC_ENABLE) {
		edac_printk(KERN_INFO, EDAC_MC, "ECC reporting and correcting on. ");
		state = true;
	}

	return state;
}

/**
 * npcm7xx_edac_mc_probe - Check controller and bind driver
 * @pdev:	Pointer to the platform_device struct
 *
 * Probes 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 npcm7xx_edac_mc_probe(struct platform_device *pdev)
{
	struct mem_ctl_info *mci;
	struct edac_mc_layer layers[1];
	struct npcm7xx_edac_priv *priv;
	struct resource *res;
	void __iomem *baseaddr;
	int rc;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	baseaddr = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(baseaddr)) {
		edac_printk(KERN_ERR, EDAC_MOD_NAME,
			    "DDR controller regs not defined\n");
		return PTR_ERR(baseaddr);
	}

	/*
	 * Check if ECC is enabled.
	 * If not, there is no useful monitoring that can be done
	 * for this controller.
	 */
	if (!npcm7xx_edac_get_eccstate(baseaddr)) {
		edac_printk(KERN_INFO, EDAC_MC, "ECC disabled\n");
		return -ENXIO;
	}

	/*
	 * Allocate an EDA controller instance and perform the appropriate
	 * initialization.
	 */
	layers[0].type = EDAC_MC_LAYER_ALL_MEM;
	layers[0].size = 1;

	mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers,
			    sizeof(struct npcm7xx_edac_priv));
	if (!mci) {
		edac_printk(KERN_ERR, EDAC_MC,
			    "Failed memory allocation for mc instance\n");
		return -ENOMEM;
	}

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

	rc = npcm7xx_edac_mc_init(mci, pdev);
	if (rc) {
		edac_printk(KERN_ERR, EDAC_MC,
			    "Failed to initialize instance\n");
		goto free_edac_mc;
	}

	/* Attempt to register it with the EDAC subsystem */
	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;
	}

	/* Register interrupts */
	rc = npcm7xx_edac_register_irq(mci, pdev);
	if (rc)
		goto free_edac_mc;

	return 0;

free_edac_mc:
	edac_mc_free(mci);

	return rc;
}

/**
 * npcm7xx_edac_mc_remove - Unbind driver from controller
 * @pdev:	Pointer to the platform_device struct
 *
 * Return: Unconditionally 0
 */
static int npcm7xx_edac_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 npcm7xx_edac_driver = {
	.probe = npcm7xx_edac_mc_probe,
	.remove = npcm7xx_edac_mc_remove,
	.driver = {
		   .name = EDAC_MOD_NAME,
		   .of_match_table = npcm7xx_edac_of_match,
	},
};

module_platform_driver(npcm7xx_edac_driver);

MODULE_AUTHOR("Quanta Computer Inc.");
MODULE_DESCRIPTION("Nuvoton NPCM7xx EDAC Driver");
MODULE_LICENSE("GPL v2");