// SPDX-License-Identifier: GPL-2.0
/*
 * SiFive L2 cache controller Driver
 *
 * Copyright (C) 2018-2019 SiFive, Inc.
 *
 */
#include <linux/debugfs.h>
#include <linux/interrupt.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <asm/sifive_l2_cache.h>

#define SIFIVE_L2_DIRECCFIX_LOW 0x100
#define SIFIVE_L2_DIRECCFIX_HIGH 0x104
#define SIFIVE_L2_DIRECCFIX_COUNT 0x108

#define SIFIVE_L2_DATECCFIX_LOW 0x140
#define SIFIVE_L2_DATECCFIX_HIGH 0x144
#define SIFIVE_L2_DATECCFIX_COUNT 0x148

#define SIFIVE_L2_DATECCFAIL_LOW 0x160
#define SIFIVE_L2_DATECCFAIL_HIGH 0x164
#define SIFIVE_L2_DATECCFAIL_COUNT 0x168

#define SIFIVE_L2_CONFIG 0x00
#define SIFIVE_L2_WAYENABLE 0x08
#define SIFIVE_L2_ECCINJECTERR 0x40

#define SIFIVE_L2_MAX_ECCINTR 3

static void __iomem *l2_base;
static int g_irq[SIFIVE_L2_MAX_ECCINTR];

enum {
	DIR_CORR = 0,
	DATA_CORR,
	DATA_UNCORR,
};

#ifdef CONFIG_DEBUG_FS
static struct dentry *sifive_test;

static ssize_t l2_write(struct file *file, const char __user *data,
			size_t count, loff_t *ppos)
{
	unsigned int val;

	if (kstrtouint_from_user(data, count, 0, &val))
		return -EINVAL;
	if ((val >= 0 && val < 0xFF) || (val >= 0x10000 && val < 0x100FF))
		writel(val, l2_base + SIFIVE_L2_ECCINJECTERR);
	else
		return -EINVAL;
	return count;
}

static const struct file_operations l2_fops = {
	.owner = THIS_MODULE,
	.open = simple_open,
	.write = l2_write
};

static void setup_sifive_debug(void)
{
	sifive_test = debugfs_create_dir("sifive_l2_cache", NULL);

	debugfs_create_file("sifive_debug_inject_error", 0200,
			    sifive_test, NULL, &l2_fops);
}
#endif

static void l2_config_read(void)
{
	u32 regval, val;

	regval = readl(l2_base + SIFIVE_L2_CONFIG);
	val = regval & 0xFF;
	pr_info("L2CACHE: No. of Banks in the cache: %d\n", val);
	val = (regval & 0xFF00) >> 8;
	pr_info("L2CACHE: No. of ways per bank: %d\n", val);
	val = (regval & 0xFF0000) >> 16;
	pr_info("L2CACHE: Sets per bank: %llu\n", (uint64_t)1 << val);
	val = (regval & 0xFF000000) >> 24;
	pr_info("L2CACHE: Bytes per cache block: %llu\n", (uint64_t)1 << val);

	regval = readl(l2_base + SIFIVE_L2_WAYENABLE);
	pr_info("L2CACHE: Index of the largest way enabled: %d\n", regval);
}

static const struct of_device_id sifive_l2_ids[] = {
	{ .compatible = "sifive,fu540-c000-ccache" },
	{ /* end of table */ },
};

static ATOMIC_NOTIFIER_HEAD(l2_err_chain);

int register_sifive_l2_error_notifier(struct notifier_block *nb)
{
	return atomic_notifier_chain_register(&l2_err_chain, nb);
}
EXPORT_SYMBOL_GPL(register_sifive_l2_error_notifier);

int unregister_sifive_l2_error_notifier(struct notifier_block *nb)
{
	return atomic_notifier_chain_unregister(&l2_err_chain, nb);
}
EXPORT_SYMBOL_GPL(unregister_sifive_l2_error_notifier);

static irqreturn_t l2_int_handler(int irq, void *device)
{
	unsigned int add_h, add_l;

	if (irq == g_irq[DIR_CORR]) {
		add_h = readl(l2_base + SIFIVE_L2_DIRECCFIX_HIGH);
		add_l = readl(l2_base + SIFIVE_L2_DIRECCFIX_LOW);
		pr_err("L2CACHE: DirError @ 0x%08X.%08X\n", add_h, add_l);
		/* Reading this register clears the DirError interrupt sig */
		readl(l2_base + SIFIVE_L2_DIRECCFIX_COUNT);
		atomic_notifier_call_chain(&l2_err_chain, SIFIVE_L2_ERR_TYPE_CE,
					   "DirECCFix");
	}
	if (irq == g_irq[DATA_CORR]) {
		add_h = readl(l2_base + SIFIVE_L2_DATECCFIX_HIGH);
		add_l = readl(l2_base + SIFIVE_L2_DATECCFIX_LOW);
		pr_err("L2CACHE: DataError @ 0x%08X.%08X\n", add_h, add_l);
		/* Reading this register clears the DataError interrupt sig */
		readl(l2_base + SIFIVE_L2_DATECCFIX_COUNT);
		atomic_notifier_call_chain(&l2_err_chain, SIFIVE_L2_ERR_TYPE_CE,
					   "DatECCFix");
	}
	if (irq == g_irq[DATA_UNCORR]) {
		add_h = readl(l2_base + SIFIVE_L2_DATECCFAIL_HIGH);
		add_l = readl(l2_base + SIFIVE_L2_DATECCFAIL_LOW);
		pr_err("L2CACHE: DataFail @ 0x%08X.%08X\n", add_h, add_l);
		/* Reading this register clears the DataFail interrupt sig */
		readl(l2_base + SIFIVE_L2_DATECCFAIL_COUNT);
		atomic_notifier_call_chain(&l2_err_chain, SIFIVE_L2_ERR_TYPE_UE,
					   "DatECCFail");
	}

	return IRQ_HANDLED;
}

static int __init sifive_l2_init(void)
{
	struct device_node *np;
	struct resource res;
	int i, rc;

	np = of_find_matching_node(NULL, sifive_l2_ids);
	if (!np)
		return -ENODEV;

	if (of_address_to_resource(np, 0, &res))
		return -ENODEV;

	l2_base = ioremap(res.start, resource_size(&res));
	if (!l2_base)
		return -ENOMEM;

	for (i = 0; i < SIFIVE_L2_MAX_ECCINTR; i++) {
		g_irq[i] = irq_of_parse_and_map(np, i);
		rc = request_irq(g_irq[i], l2_int_handler, 0, "l2_ecc", NULL);
		if (rc) {
			pr_err("L2CACHE: Could not request IRQ %d\n", g_irq[i]);
			return rc;
		}
	}

	l2_config_read();

#ifdef CONFIG_DEBUG_FS
	setup_sifive_debug();
#endif
	return 0;
}
device_initcall(sifive_l2_init);