// SPDX-License-Identifier: GPL-2.0-only
// Copyright (c) 2022 Nuvoton Technology Corporation

#include <linux/debugfs.h>
#include <linux/iopoll.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include "edac_module.h"

#define EDAC_MOD_NAME			"npcm-edac"
#define EDAC_MSG_SIZE			256

/* chip serials */
#define NPCM7XX_CHIP			BIT(0)
#define NPCM8XX_CHIP			BIT(1)

/* syndrome values */
#define UE_SYNDROME			0x03

/* error injection */
#define ERROR_TYPE_CORRECTABLE		0
#define ERROR_TYPE_UNCORRECTABLE	1
#define ERROR_LOCATION_DATA		0
#define ERROR_LOCATION_CHECKCODE	1
#define ERROR_BIT_DATA_MAX		63
#define ERROR_BIT_CHECKCODE_MAX		7

static char data_synd[] = {
	0xf4, 0xf1, 0xec, 0xea, 0xe9, 0xe6, 0xe5, 0xe3,
	0xdc, 0xda, 0xd9, 0xd6, 0xd5, 0xd3, 0xce, 0xcb,
	0xb5, 0xb0, 0xad, 0xab, 0xa8, 0xa7, 0xa4, 0xa2,
	0x9d, 0x9b, 0x98, 0x97, 0x94, 0x92, 0x8f, 0x8a,
	0x75, 0x70, 0x6d, 0x6b, 0x68, 0x67, 0x64, 0x62,
	0x5e, 0x5b, 0x58, 0x57, 0x54, 0x52, 0x4f, 0x4a,
	0x34, 0x31, 0x2c, 0x2a, 0x29, 0x26, 0x25, 0x23,
	0x1c, 0x1a, 0x19, 0x16, 0x15, 0x13, 0x0e, 0x0b
};

static struct regmap *npcm_regmap;

struct npcm_platform_data {
	/* chip serials */
	int chip;

	/* memory controller registers */
	u32 ctl_ecc_en;
	u32 ctl_int_status;
	u32 ctl_int_ack;
	u32 ctl_int_mask_master;
	u32 ctl_int_mask_ecc;
	u32 ctl_ce_addr_l;
	u32 ctl_ce_addr_h;
	u32 ctl_ce_data_l;
	u32 ctl_ce_data_h;
	u32 ctl_ce_synd;
	u32 ctl_ue_addr_l;
	u32 ctl_ue_addr_h;
	u32 ctl_ue_data_l;
	u32 ctl_ue_data_h;
	u32 ctl_ue_synd;
	u32 ctl_source_id;
	u32 ctl_controller_busy;
	u32 ctl_xor_check_bits;

	/* masks and shifts */
	u32 ecc_en_mask;
	u32 int_status_ce_mask;
	u32 int_status_ue_mask;
	u32 int_ack_ce_mask;
	u32 int_ack_ue_mask;
	u32 int_mask_master_non_ecc_mask;
	u32 int_mask_master_global_mask;
	u32 int_mask_ecc_non_event_mask;
	u32 ce_addr_h_mask;
	u32 ce_synd_mask;
	u32 ce_synd_shift;
	u32 ue_addr_h_mask;
	u32 ue_synd_mask;
	u32 ue_synd_shift;
	u32 source_id_ce_mask;
	u32 source_id_ce_shift;
	u32 source_id_ue_mask;
	u32 source_id_ue_shift;
	u32 controller_busy_mask;
	u32 xor_check_bits_mask;
	u32 xor_check_bits_shift;
	u32 writeback_en_mask;
	u32 fwc_mask;
};

struct priv_data {
	void __iomem *reg;
	char message[EDAC_MSG_SIZE];
	const struct npcm_platform_data *pdata;

	/* error injection */
	struct dentry *debugfs;
	u8 error_type;
	u8 location;
	u8 bit;
};

static void handle_ce(struct mem_ctl_info *mci)
{
	struct priv_data *priv = mci->pvt_info;
	const struct npcm_platform_data *pdata;
	u32 val_h = 0, val_l, id, synd;
	u64 addr = 0, data = 0;

	pdata = priv->pdata;
	regmap_read(npcm_regmap, pdata->ctl_ce_addr_l, &val_l);
	if (pdata->chip == NPCM8XX_CHIP) {
		regmap_read(npcm_regmap, pdata->ctl_ce_addr_h, &val_h);
		val_h &= pdata->ce_addr_h_mask;
	}
	addr = ((addr | val_h) << 32) | val_l;

	regmap_read(npcm_regmap, pdata->ctl_ce_data_l, &val_l);
	if (pdata->chip == NPCM8XX_CHIP)
		regmap_read(npcm_regmap, pdata->ctl_ce_data_h, &val_h);
	data = ((data | val_h) << 32) | val_l;

	regmap_read(npcm_regmap, pdata->ctl_source_id, &id);
	id = (id & pdata->source_id_ce_mask) >> pdata->source_id_ce_shift;

	regmap_read(npcm_regmap, pdata->ctl_ce_synd, &synd);
	synd = (synd & pdata->ce_synd_mask) >> pdata->ce_synd_shift;

	snprintf(priv->message, EDAC_MSG_SIZE,
		 "addr = 0x%llx, data = 0x%llx, id = 0x%x", addr, data, id);

	edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci, 1, addr >> PAGE_SHIFT,
			     addr & ~PAGE_MASK, synd, 0, 0, -1, priv->message, "");
}

static void handle_ue(struct mem_ctl_info *mci)
{
	struct priv_data *priv = mci->pvt_info;
	const struct npcm_platform_data *pdata;
	u32 val_h = 0, val_l, id, synd;
	u64 addr = 0, data = 0;

	pdata = priv->pdata;
	regmap_read(npcm_regmap, pdata->ctl_ue_addr_l, &val_l);
	if (pdata->chip == NPCM8XX_CHIP) {
		regmap_read(npcm_regmap, pdata->ctl_ue_addr_h, &val_h);
		val_h &= pdata->ue_addr_h_mask;
	}
	addr = ((addr | val_h) << 32) | val_l;

	regmap_read(npcm_regmap, pdata->ctl_ue_data_l, &val_l);
	if (pdata->chip == NPCM8XX_CHIP)
		regmap_read(npcm_regmap, pdata->ctl_ue_data_h, &val_h);
	data = ((data | val_h) << 32) | val_l;

	regmap_read(npcm_regmap, pdata->ctl_source_id, &id);
	id = (id & pdata->source_id_ue_mask) >> pdata->source_id_ue_shift;

	regmap_read(npcm_regmap, pdata->ctl_ue_synd, &synd);
	synd = (synd & pdata->ue_synd_mask) >> pdata->ue_synd_shift;

	snprintf(priv->message, EDAC_MSG_SIZE,
		 "addr = 0x%llx, data = 0x%llx, id = 0x%x", addr, data, id);

	edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci, 1, addr >> PAGE_SHIFT,
			     addr & ~PAGE_MASK, synd, 0, 0, -1, priv->message, "");
}

static irqreturn_t edac_ecc_isr(int irq, void *dev_id)
{
	const struct npcm_platform_data *pdata;
	struct mem_ctl_info *mci = dev_id;
	u32 status;

	pdata = ((struct priv_data *)mci->pvt_info)->pdata;
	regmap_read(npcm_regmap, pdata->ctl_int_status, &status);
	if (status & pdata->int_status_ce_mask) {
		handle_ce(mci);

		/* acknowledge the CE interrupt */
		regmap_write(npcm_regmap, pdata->ctl_int_ack,
			     pdata->int_ack_ce_mask);
		return IRQ_HANDLED;
	} else if (status & pdata->int_status_ue_mask) {
		handle_ue(mci);

		/* acknowledge the UE interrupt */
		regmap_write(npcm_regmap, pdata->ctl_int_ack,
			     pdata->int_ack_ue_mask);
		return IRQ_HANDLED;
	}

	WARN_ON_ONCE(1);
	return IRQ_NONE;
}

static ssize_t force_ecc_error(struct file *file, const char __user *data,
			       size_t count, loff_t *ppos)
{
	struct device *dev = file->private_data;
	struct mem_ctl_info *mci = to_mci(dev);
	struct priv_data *priv = mci->pvt_info;
	const struct npcm_platform_data *pdata;
	u32 val, syndrome;
	int ret;

	pdata = priv->pdata;
	edac_printk(KERN_INFO, EDAC_MOD_NAME,
		    "force an ECC error, type = %d, location = %d, bit = %d\n",
		    priv->error_type, priv->location, priv->bit);

	/* ensure no pending writes */
	ret = regmap_read_poll_timeout(npcm_regmap, pdata->ctl_controller_busy,
				       val, !(val & pdata->controller_busy_mask),
				       1000, 10000);
	if (ret) {
		edac_printk(KERN_INFO, EDAC_MOD_NAME,
			    "wait pending writes timeout\n");
		return count;
	}

	regmap_read(npcm_regmap, pdata->ctl_xor_check_bits, &val);
	val &= ~pdata->xor_check_bits_mask;

	/* write syndrome to XOR_CHECK_BITS */
	if (priv->error_type == ERROR_TYPE_CORRECTABLE) {
		if (priv->location == ERROR_LOCATION_DATA &&
		    priv->bit > ERROR_BIT_DATA_MAX) {
			edac_printk(KERN_INFO, EDAC_MOD_NAME,
				    "data bit should not exceed %d (%d)\n",
				    ERROR_BIT_DATA_MAX, priv->bit);
			return count;
		}

		if (priv->location == ERROR_LOCATION_CHECKCODE &&
		    priv->bit > ERROR_BIT_CHECKCODE_MAX) {
			edac_printk(KERN_INFO, EDAC_MOD_NAME,
				    "checkcode bit should not exceed %d (%d)\n",
				    ERROR_BIT_CHECKCODE_MAX, priv->bit);
			return count;
		}

		syndrome = priv->location ? 1 << priv->bit
					  : data_synd[priv->bit];

		regmap_write(npcm_regmap, pdata->ctl_xor_check_bits,
			     val | (syndrome << pdata->xor_check_bits_shift) |
			     pdata->writeback_en_mask);
	} else if (priv->error_type == ERROR_TYPE_UNCORRECTABLE) {
		regmap_write(npcm_regmap, pdata->ctl_xor_check_bits,
			     val | (UE_SYNDROME << pdata->xor_check_bits_shift));
	}

	/* force write check */
	regmap_update_bits(npcm_regmap, pdata->ctl_xor_check_bits,
			   pdata->fwc_mask, pdata->fwc_mask);

	return count;
}

static const struct file_operations force_ecc_error_fops = {
	.open = simple_open,
	.write = force_ecc_error,
	.llseek = generic_file_llseek,
};

/*
 * Setup debugfs for error injection.
 *
 * Nodes:
 *   error_type		- 0: CE, 1: UE
 *   location		- 0: data, 1: checkcode
 *   bit		- 0 ~ 63 for data and 0 ~ 7 for checkcode
 *   force_ecc_error	- trigger
 *
 * Examples:
 *   1. Inject a correctable error (CE) at checkcode bit 7.
 *      ~# echo 0 > /sys/kernel/debug/edac/npcm-edac/error_type
 *      ~# echo 1 > /sys/kernel/debug/edac/npcm-edac/location
 *      ~# echo 7 > /sys/kernel/debug/edac/npcm-edac/bit
 *      ~# echo 1 > /sys/kernel/debug/edac/npcm-edac/force_ecc_error
 *
 *   2. Inject an uncorrectable error (UE).
 *      ~# echo 1 > /sys/kernel/debug/edac/npcm-edac/error_type
 *      ~# echo 1 > /sys/kernel/debug/edac/npcm-edac/force_ecc_error
 */
static void setup_debugfs(struct mem_ctl_info *mci)
{
	struct priv_data *priv = mci->pvt_info;

	priv->debugfs = edac_debugfs_create_dir(mci->mod_name);
	if (!priv->debugfs)
		return;

	edac_debugfs_create_x8("error_type", 0644, priv->debugfs, &priv->error_type);
	edac_debugfs_create_x8("location", 0644, priv->debugfs, &priv->location);
	edac_debugfs_create_x8("bit", 0644, priv->debugfs, &priv->bit);
	edac_debugfs_create_file("force_ecc_error", 0200, priv->debugfs,
				 &mci->dev, &force_ecc_error_fops);
}

static int setup_irq(struct mem_ctl_info *mci, struct platform_device *pdev)
{
	const struct npcm_platform_data *pdata;
	int ret, irq;

	pdata = ((struct priv_data *)mci->pvt_info)->pdata;
	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		edac_printk(KERN_ERR, EDAC_MOD_NAME, "IRQ not defined in DTS\n");
		return irq;
	}

	ret = devm_request_irq(&pdev->dev, irq, edac_ecc_isr, 0,
			       dev_name(&pdev->dev), mci);
	if (ret < 0) {
		edac_printk(KERN_ERR, EDAC_MOD_NAME, "failed to request IRQ\n");
		return ret;
	}

	/* enable the functional group of ECC and mask the others */
	regmap_write(npcm_regmap, pdata->ctl_int_mask_master,
		     pdata->int_mask_master_non_ecc_mask);

	if (pdata->chip == NPCM8XX_CHIP)
		regmap_write(npcm_regmap, pdata->ctl_int_mask_ecc,
			     pdata->int_mask_ecc_non_event_mask);

	return 0;
}

static const struct regmap_config npcm_regmap_cfg = {
	.reg_bits	= 32,
	.reg_stride	= 4,
	.val_bits	= 32,
};

static int edac_probe(struct platform_device *pdev)
{
	const struct npcm_platform_data *pdata;
	struct device *dev = &pdev->dev;
	struct edac_mc_layer layers[1];
	struct mem_ctl_info *mci;
	struct priv_data *priv;
	void __iomem *reg;
	u32 val;
	int rc;

	reg = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(reg))
		return PTR_ERR(reg);

	npcm_regmap = devm_regmap_init_mmio(dev, reg, &npcm_regmap_cfg);
	if (IS_ERR(npcm_regmap))
		return PTR_ERR(npcm_regmap);

	pdata = of_device_get_match_data(dev);
	if (!pdata)
		return -EINVAL;

	/* bail out if ECC is not enabled */
	regmap_read(npcm_regmap, pdata->ctl_ecc_en, &val);
	if (!(val & pdata->ecc_en_mask)) {
		edac_printk(KERN_ERR, EDAC_MOD_NAME, "ECC is not enabled\n");
		return -EPERM;
	}

	edac_op_state = EDAC_OPSTATE_INT;

	layers[0].type = EDAC_MC_LAYER_ALL_MEM;
	layers[0].size = 1;

	mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers,
			    sizeof(struct priv_data));
	if (!mci)
		return -ENOMEM;

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

	mci->mtype_cap = MEM_FLAG_DDR4;
	mci->edac_ctl_cap = EDAC_FLAG_SECDED;
	mci->scrub_cap = SCRUB_FLAG_HW_SRC;
	mci->scrub_mode = SCRUB_HW_SRC;
	mci->edac_cap = EDAC_FLAG_SECDED;
	mci->ctl_name = "npcm_ddr_controller";
	mci->dev_name = dev_name(&pdev->dev);
	mci->mod_name = EDAC_MOD_NAME;
	mci->ctl_page_to_phys = NULL;

	rc = setup_irq(mci, pdev);
	if (rc)
		goto free_edac_mc;

	rc = edac_mc_add_mc(mci);
	if (rc)
		goto free_edac_mc;

	if (IS_ENABLED(CONFIG_EDAC_DEBUG) && pdata->chip == NPCM8XX_CHIP)
		setup_debugfs(mci);

	return rc;

free_edac_mc:
	edac_mc_free(mci);
	return rc;
}

static void edac_remove(struct platform_device *pdev)
{
	struct mem_ctl_info *mci = platform_get_drvdata(pdev);
	struct priv_data *priv = mci->pvt_info;
	const struct npcm_platform_data *pdata;

	pdata = priv->pdata;
	if (IS_ENABLED(CONFIG_EDAC_DEBUG) && pdata->chip == NPCM8XX_CHIP)
		edac_debugfs_remove_recursive(priv->debugfs);

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

	regmap_write(npcm_regmap, pdata->ctl_int_mask_master,
		     pdata->int_mask_master_global_mask);
	regmap_update_bits(npcm_regmap, pdata->ctl_ecc_en, pdata->ecc_en_mask, 0);
}

static const struct npcm_platform_data npcm750_edac = {
	.chip				= NPCM7XX_CHIP,

	/* memory controller registers */
	.ctl_ecc_en			= 0x174,
	.ctl_int_status			= 0x1d0,
	.ctl_int_ack			= 0x1d4,
	.ctl_int_mask_master		= 0x1d8,
	.ctl_ce_addr_l			= 0x188,
	.ctl_ce_data_l			= 0x190,
	.ctl_ce_synd			= 0x18c,
	.ctl_ue_addr_l			= 0x17c,
	.ctl_ue_data_l			= 0x184,
	.ctl_ue_synd			= 0x180,
	.ctl_source_id			= 0x194,

	/* masks and shifts */
	.ecc_en_mask			= BIT(24),
	.int_status_ce_mask		= GENMASK(4, 3),
	.int_status_ue_mask		= GENMASK(6, 5),
	.int_ack_ce_mask		= GENMASK(4, 3),
	.int_ack_ue_mask		= GENMASK(6, 5),
	.int_mask_master_non_ecc_mask	= GENMASK(30, 7) | GENMASK(2, 0),
	.int_mask_master_global_mask	= BIT(31),
	.ce_synd_mask			= GENMASK(6, 0),
	.ce_synd_shift			= 0,
	.ue_synd_mask			= GENMASK(6, 0),
	.ue_synd_shift			= 0,
	.source_id_ce_mask		= GENMASK(29, 16),
	.source_id_ce_shift		= 16,
	.source_id_ue_mask		= GENMASK(13, 0),
	.source_id_ue_shift		= 0,
};

static const struct npcm_platform_data npcm845_edac = {
	.chip =				NPCM8XX_CHIP,

	/* memory controller registers */
	.ctl_ecc_en			= 0x16c,
	.ctl_int_status			= 0x228,
	.ctl_int_ack			= 0x244,
	.ctl_int_mask_master		= 0x220,
	.ctl_int_mask_ecc		= 0x260,
	.ctl_ce_addr_l			= 0x18c,
	.ctl_ce_addr_h			= 0x190,
	.ctl_ce_data_l			= 0x194,
	.ctl_ce_data_h			= 0x198,
	.ctl_ce_synd			= 0x190,
	.ctl_ue_addr_l			= 0x17c,
	.ctl_ue_addr_h			= 0x180,
	.ctl_ue_data_l			= 0x184,
	.ctl_ue_data_h			= 0x188,
	.ctl_ue_synd			= 0x180,
	.ctl_source_id			= 0x19c,
	.ctl_controller_busy		= 0x20c,
	.ctl_xor_check_bits		= 0x174,

	/* masks and shifts */
	.ecc_en_mask			= GENMASK(17, 16),
	.int_status_ce_mask		= GENMASK(1, 0),
	.int_status_ue_mask		= GENMASK(3, 2),
	.int_ack_ce_mask		= GENMASK(1, 0),
	.int_ack_ue_mask		= GENMASK(3, 2),
	.int_mask_master_non_ecc_mask	= GENMASK(30, 3) | GENMASK(1, 0),
	.int_mask_master_global_mask	= BIT(31),
	.int_mask_ecc_non_event_mask	= GENMASK(8, 4),
	.ce_addr_h_mask			= GENMASK(1, 0),
	.ce_synd_mask			= GENMASK(15, 8),
	.ce_synd_shift			= 8,
	.ue_addr_h_mask			= GENMASK(1, 0),
	.ue_synd_mask			= GENMASK(15, 8),
	.ue_synd_shift			= 8,
	.source_id_ce_mask		= GENMASK(29, 16),
	.source_id_ce_shift		= 16,
	.source_id_ue_mask		= GENMASK(13, 0),
	.source_id_ue_shift		= 0,
	.controller_busy_mask		= BIT(0),
	.xor_check_bits_mask		= GENMASK(23, 16),
	.xor_check_bits_shift		= 16,
	.writeback_en_mask		= BIT(24),
	.fwc_mask			= BIT(8),
};

static const struct of_device_id npcm_edac_of_match[] = {
	{
		.compatible = "nuvoton,npcm750-memory-controller",
		.data = &npcm750_edac
	},
	{
		.compatible = "nuvoton,npcm845-memory-controller",
		.data = &npcm845_edac
	},
	{},
};

MODULE_DEVICE_TABLE(of, npcm_edac_of_match);

static struct platform_driver npcm_edac_driver = {
	.driver = {
		.name = "npcm-edac",
		.of_match_table = npcm_edac_of_match,
	},
	.probe = edac_probe,
	.remove_new = edac_remove,
};

module_platform_driver(npcm_edac_driver);

MODULE_AUTHOR("Medad CChien <medadyoung@gmail.com>");
MODULE_AUTHOR("Marvin Lin <kflin@nuvoton.com>");
MODULE_DESCRIPTION("Nuvoton NPCM EDAC Driver");
MODULE_LICENSE("GPL");