// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2021 Western Digital Corporation or its affiliates.
 * Copyright (C) 2022 Ventana Micro Systems Inc.
 */

#include <linux/acpi.h>
#include <linux/bitfield.h>
#include <linux/irqchip/riscv-aplic.h>
#include <linux/irqchip/riscv-imsic.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/printk.h>
#include <linux/syscore_ops.h>

#include "irq-riscv-aplic-main.h"

static LIST_HEAD(aplics);

static void aplic_restore_states(struct aplic_priv *priv)
{
	struct aplic_saved_regs *saved_regs = &priv->saved_hw_regs;
	struct aplic_src_ctrl *srcs;
	void __iomem *regs;
	u32 nr_irqs, i;

	regs = priv->regs;
	writel(saved_regs->domaincfg, regs + APLIC_DOMAINCFG);
#ifdef CONFIG_RISCV_M_MODE
	writel(saved_regs->msiaddr, regs + APLIC_xMSICFGADDR);
	writel(saved_regs->msiaddrh, regs + APLIC_xMSICFGADDRH);
#endif
	/*
	 * The sourcecfg[i] has to be restored prior to the target[i], interrupt-pending and
	 * interrupt-enable bits. The AIA specification states that "Whenever interrupt source i is
	 * inactive in an interrupt domain, the corresponding interrupt-pending and interrupt-enable
	 * bits within the domain are read-only zeros, and register target[i] is also read-only
	 * zero."
	 */
	nr_irqs = priv->nr_irqs;
	for (i = 0; i < nr_irqs; i++) {
		srcs = &priv->saved_hw_regs.srcs[i];
		writel(srcs->sourcecfg, regs + APLIC_SOURCECFG_BASE + i * sizeof(u32));
		writel(srcs->target, regs + APLIC_TARGET_BASE + i * sizeof(u32));
	}

	for (i = 0; i <= nr_irqs; i += 32) {
		srcs = &priv->saved_hw_regs.srcs[i];
		writel(-1U, regs + APLIC_CLRIE_BASE + (i / 32) * sizeof(u32));
		writel(srcs->ie, regs + APLIC_SETIE_BASE + (i / 32) * sizeof(u32));

		/* Re-trigger the interrupts if it forwards interrupts to target harts by MSIs */
		if (!priv->nr_idcs)
			writel(readl(regs + APLIC_CLRIP_BASE + (i / 32) * sizeof(u32)),
			       regs + APLIC_SETIP_BASE + (i / 32) * sizeof(u32));
	}

	if (priv->nr_idcs)
		aplic_direct_restore_states(priv);
}

static void aplic_save_states(struct aplic_priv *priv)
{
	struct aplic_src_ctrl *srcs;
	void __iomem *regs;
	u32 i, nr_irqs;

	regs = priv->regs;
	nr_irqs = priv->nr_irqs;
	/* The valid interrupt source IDs range from 1 to N, where N is priv->nr_irqs */
	for (i = 0; i < nr_irqs; i++) {
		srcs = &priv->saved_hw_regs.srcs[i];
		srcs->target = readl(regs + APLIC_TARGET_BASE + i * sizeof(u32));

		if (i % 32)
			continue;

		srcs->ie = readl(regs + APLIC_SETIE_BASE + (i / 32) * sizeof(u32));
	}

	/* Save the nr_irqs bit if needed */
	if (!(nr_irqs % 32)) {
		srcs = &priv->saved_hw_regs.srcs[nr_irqs];
		srcs->ie = readl(regs + APLIC_SETIE_BASE + (nr_irqs / 32) * sizeof(u32));
	}
}

static int aplic_syscore_suspend(void *data)
{
	struct aplic_priv *priv;

	list_for_each_entry(priv, &aplics, head)
		aplic_save_states(priv);

	return 0;
}

static void aplic_syscore_resume(void *data)
{
	struct aplic_priv *priv;

	list_for_each_entry(priv, &aplics, head)
		aplic_restore_states(priv);
}

static struct syscore_ops aplic_syscore_ops = {
	.suspend = aplic_syscore_suspend,
	.resume = aplic_syscore_resume,
};

static struct syscore aplic_syscore = {
	.ops = &aplic_syscore_ops,
};

static bool aplic_syscore_registered __ro_after_init;

static void aplic_syscore_init(void)
{
	if (!aplic_syscore_registered) {
		register_syscore(&aplic_syscore);
		aplic_syscore_registered = true;
	}
}

static int aplic_pm_notifier(struct notifier_block *nb, unsigned long action, void *data)
{
	struct aplic_priv *priv = container_of(nb, struct aplic_priv, genpd_nb);

	switch (action) {
	case GENPD_NOTIFY_PRE_OFF:
		aplic_save_states(priv);
		break;
	case GENPD_NOTIFY_ON:
		aplic_restore_states(priv);
		break;
	default:
		break;
	}

	return 0;
}

static void aplic_pm_remove(void *data)
{
	struct aplic_priv *priv = data;
	struct device *dev = priv->dev;

	list_del(&priv->head);
	if (dev->pm_domain)
		dev_pm_genpd_remove_notifier(dev);
}

static int aplic_pm_add(struct device *dev, struct aplic_priv *priv)
{
	struct aplic_src_ctrl *srcs;
	int ret;

	srcs = devm_kzalloc(dev, (priv->nr_irqs + 1) * sizeof(*srcs), GFP_KERNEL);
	if (!srcs)
		return -ENOMEM;

	priv->saved_hw_regs.srcs = srcs;
	list_add(&priv->head, &aplics);
	if (dev->pm_domain) {
		priv->genpd_nb.notifier_call = aplic_pm_notifier;
		ret = dev_pm_genpd_add_notifier(dev, &priv->genpd_nb);
		if (ret)
			goto remove_head;

		ret = devm_pm_runtime_enable(dev);
		if (ret)
			goto remove_notifier;
	}

	return devm_add_action_or_reset(dev, aplic_pm_remove, priv);

remove_notifier:
	dev_pm_genpd_remove_notifier(dev);
remove_head:
	list_del(&priv->head);
	return ret;
}

void aplic_irq_unmask(struct irq_data *d)
{
	struct aplic_priv *priv = irq_data_get_irq_chip_data(d);

	writel(d->hwirq, priv->regs + APLIC_SETIENUM);
}

void aplic_irq_mask(struct irq_data *d)
{
	struct aplic_priv *priv = irq_data_get_irq_chip_data(d);

	writel(d->hwirq, priv->regs + APLIC_CLRIENUM);
}

int aplic_irq_set_type(struct irq_data *d, unsigned int type)
{
	struct aplic_priv *priv = irq_data_get_irq_chip_data(d);
	void __iomem *sourcecfg;
	u32 val = 0;

	switch (type) {
	case IRQ_TYPE_NONE:
		val = APLIC_SOURCECFG_SM_INACTIVE;
		break;
	case IRQ_TYPE_LEVEL_LOW:
		val = APLIC_SOURCECFG_SM_LEVEL_LOW;
		break;
	case IRQ_TYPE_LEVEL_HIGH:
		val = APLIC_SOURCECFG_SM_LEVEL_HIGH;
		break;
	case IRQ_TYPE_EDGE_FALLING:
		val = APLIC_SOURCECFG_SM_EDGE_FALL;
		break;
	case IRQ_TYPE_EDGE_RISING:
		val = APLIC_SOURCECFG_SM_EDGE_RISE;
		break;
	default:
		return -EINVAL;
	}

	sourcecfg = priv->regs + APLIC_SOURCECFG_BASE;
	sourcecfg += (d->hwirq - 1) * sizeof(u32);
	writel(val, sourcecfg);

	priv->saved_hw_regs.srcs[d->hwirq - 1].sourcecfg = val;

	return 0;
}

int aplic_irqdomain_translate(struct irq_fwspec *fwspec, u32 gsi_base,
			      unsigned long *hwirq, unsigned int *type)
{
	if (WARN_ON(fwspec->param_count < 2))
		return -EINVAL;
	if (WARN_ON(!fwspec->param[0]))
		return -EINVAL;

	/* For DT, gsi_base is always zero. */
	*hwirq = fwspec->param[0] - gsi_base;
	*type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;

	WARN_ON(*type == IRQ_TYPE_NONE);

	return 0;
}

void aplic_init_hw_global(struct aplic_priv *priv, bool msi_mode)
{
	struct aplic_saved_regs *saved_regs = &priv->saved_hw_regs;
	u32 val;
#ifdef CONFIG_RISCV_M_MODE
	u32 valh;

	if (msi_mode) {
		val = lower_32_bits(priv->msicfg.base_ppn);
		valh = FIELD_PREP(APLIC_xMSICFGADDRH_BAPPN, upper_32_bits(priv->msicfg.base_ppn));
		valh |= FIELD_PREP(APLIC_xMSICFGADDRH_LHXW, priv->msicfg.lhxw);
		valh |= FIELD_PREP(APLIC_xMSICFGADDRH_HHXW, priv->msicfg.hhxw);
		valh |= FIELD_PREP(APLIC_xMSICFGADDRH_LHXS, priv->msicfg.lhxs);
		valh |= FIELD_PREP(APLIC_xMSICFGADDRH_HHXS, priv->msicfg.hhxs);
		writel(val, priv->regs + APLIC_xMSICFGADDR);
		writel(valh, priv->regs + APLIC_xMSICFGADDRH);
		saved_regs->msiaddr = val;
		saved_regs->msiaddrh = valh;
	}
#endif

	/* Setup APLIC domaincfg register */
	val = readl(priv->regs + APLIC_DOMAINCFG);
	val |= APLIC_DOMAINCFG_IE;
	if (msi_mode)
		val |= APLIC_DOMAINCFG_DM;
	writel(val, priv->regs + APLIC_DOMAINCFG);
	if (readl(priv->regs + APLIC_DOMAINCFG) != val)
		dev_warn(priv->dev, "unable to write 0x%x in domaincfg\n", val);

	saved_regs->domaincfg = val;
}

static void aplic_init_hw_irqs(struct aplic_priv *priv)
{
	int i;

	/* Disable all interrupts */
	for (i = 0; i <= priv->nr_irqs; i += 32)
		writel(-1U, priv->regs + APLIC_CLRIE_BASE + (i / 32) * sizeof(u32));

	/* Set interrupt type and default priority for all interrupts */
	for (i = 1; i <= priv->nr_irqs; i++) {
		writel(0, priv->regs + APLIC_SOURCECFG_BASE + (i - 1) * sizeof(u32));
		writel(APLIC_DEFAULT_PRIORITY,
		       priv->regs + APLIC_TARGET_BASE + (i - 1) * sizeof(u32));
	}

	/* Clear APLIC domaincfg */
	writel(0, priv->regs + APLIC_DOMAINCFG);
}

#ifdef CONFIG_ACPI
static const struct acpi_device_id aplic_acpi_match[] = {
	{ "RSCV0002", 0 },
	{}
};
MODULE_DEVICE_TABLE(acpi, aplic_acpi_match);

#endif

int aplic_setup_priv(struct aplic_priv *priv, struct device *dev, void __iomem *regs)
{
	struct device_node *np = to_of_node(dev->fwnode);
	struct of_phandle_args parent;
	int rc;

	/* Save device pointer and register base */
	priv->dev = dev;
	priv->regs = regs;

	if (np) {
		/* Find out number of interrupt sources */
		rc = of_property_read_u32(np, "riscv,num-sources", &priv->nr_irqs);
		if (rc) {
			dev_err(dev, "failed to get number of interrupt sources\n");
			return rc;
		}

		/*
		 * Find out number of IDCs based on parent interrupts
		 *
		 * If "msi-parent" property is present then we ignore the
		 * APLIC IDCs which forces the APLIC driver to use MSI mode.
		 */
		if (!of_property_present(np, "msi-parent")) {
			while (!of_irq_parse_one(np, priv->nr_idcs, &parent))
				priv->nr_idcs++;
		}
	} else {
		rc = riscv_acpi_get_gsi_info(dev->fwnode, &priv->gsi_base, &priv->acpi_aplic_id,
					     &priv->nr_irqs, &priv->nr_idcs);
		if (rc) {
			dev_err(dev, "failed to find GSI mapping\n");
			return rc;
		}
	}

	/* Setup initial state APLIC interrupts */
	aplic_init_hw_irqs(priv);

	return aplic_pm_add(dev, priv);
}

static int aplic_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	bool msi_mode = false;
	void __iomem *regs;
	int rc;

	/* Map the MMIO registers */
	regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(regs)) {
		dev_err(dev, "failed map MMIO registers\n");
		return PTR_ERR(regs);
	}

	/*
	 * If msi-parent property is present then setup APLIC MSI
	 * mode otherwise setup APLIC direct mode.
	 */
	if (is_of_node(dev->fwnode))
		msi_mode = of_property_present(to_of_node(dev->fwnode), "msi-parent");
	else
		msi_mode = imsic_acpi_get_fwnode(NULL) ? 1 : 0;

	if (msi_mode)
		rc = aplic_msi_setup(dev, regs);
	else
		rc = aplic_direct_setup(dev, regs);

	if (rc) {
		dev_err_probe(dev, rc, "failed to setup APLIC in %s mode\n",
			      msi_mode ? "MSI" : "direct");
		return rc;
	}

	aplic_syscore_init();

#ifdef CONFIG_ACPI
	if (!acpi_disabled)
		acpi_dev_clear_dependencies(ACPI_COMPANION(dev));
#endif

	return 0;
}

static const struct of_device_id aplic_match[] = {
	{ .compatible = "riscv,aplic" },
	{}
};

static struct platform_driver aplic_driver = {
	.driver = {
		.name		= "riscv-aplic",
		.of_match_table	= aplic_match,
		.acpi_match_table = ACPI_PTR(aplic_acpi_match),
	},
	.probe = aplic_probe,
};
builtin_platform_driver(aplic_driver);