/*
 * Copyright (C) 2013, 2014 ARM Limited, All Rights Reserved.
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/acpi.h>
#include <linux/cpu.h>
#include <linux/cpu_pm.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/percpu.h>
#include <linux/slab.h>

#include <linux/irqchip.h>
#include <linux/irqchip/arm-gic-v3.h>

#include <asm/cputype.h>
#include <asm/exception.h>
#include <asm/smp_plat.h>
#include <asm/virt.h>

#include "irq-gic-common.h"

struct redist_region {
	void __iomem		*redist_base;
	phys_addr_t		phys_base;
	bool			single_redist;
};

struct gic_chip_data {
	void __iomem		*dist_base;
	struct redist_region	*redist_regions;
	struct rdists		rdists;
	struct irq_domain	*domain;
	u64			redist_stride;
	u32			nr_redist_regions;
	unsigned int		irq_nr;
};

static struct gic_chip_data gic_data __read_mostly;
static struct static_key supports_deactivate = STATIC_KEY_INIT_TRUE;

#define gic_data_rdist()		(this_cpu_ptr(gic_data.rdists.rdist))
#define gic_data_rdist_rd_base()	(gic_data_rdist()->rd_base)
#define gic_data_rdist_sgi_base()	(gic_data_rdist_rd_base() + SZ_64K)

/* Our default, arbitrary priority value. Linux only uses one anyway. */
#define DEFAULT_PMR_VALUE	0xf0

static inline unsigned int gic_irq(struct irq_data *d)
{
	return d->hwirq;
}

static inline int gic_irq_in_rdist(struct irq_data *d)
{
	return gic_irq(d) < 32;
}

static inline void __iomem *gic_dist_base(struct irq_data *d)
{
	if (gic_irq_in_rdist(d))	/* SGI+PPI -> SGI_base for this CPU */
		return gic_data_rdist_sgi_base();

	if (d->hwirq <= 1023)		/* SPI -> dist_base */
		return gic_data.dist_base;

	return NULL;
}

static void gic_do_wait_for_rwp(void __iomem *base)
{
	u32 count = 1000000;	/* 1s! */

	while (readl_relaxed(base + GICD_CTLR) & GICD_CTLR_RWP) {
		count--;
		if (!count) {
			pr_err_ratelimited("RWP timeout, gone fishing\n");
			return;
		}
		cpu_relax();
		udelay(1);
	};
}

/* Wait for completion of a distributor change */
static void gic_dist_wait_for_rwp(void)
{
	gic_do_wait_for_rwp(gic_data.dist_base);
}

/* Wait for completion of a redistributor change */
static void gic_redist_wait_for_rwp(void)
{
	gic_do_wait_for_rwp(gic_data_rdist_rd_base());
}

#ifdef CONFIG_ARM64
static DEFINE_STATIC_KEY_FALSE(is_cavium_thunderx);

static u64 __maybe_unused gic_read_iar(void)
{
	if (static_branch_unlikely(&is_cavium_thunderx))
		return gic_read_iar_cavium_thunderx();
	else
		return gic_read_iar_common();
}
#endif

static void gic_enable_redist(bool enable)
{
	void __iomem *rbase;
	u32 count = 1000000;	/* 1s! */
	u32 val;

	rbase = gic_data_rdist_rd_base();

	val = readl_relaxed(rbase + GICR_WAKER);
	if (enable)
		/* Wake up this CPU redistributor */
		val &= ~GICR_WAKER_ProcessorSleep;
	else
		val |= GICR_WAKER_ProcessorSleep;
	writel_relaxed(val, rbase + GICR_WAKER);

	if (!enable) {		/* Check that GICR_WAKER is writeable */
		val = readl_relaxed(rbase + GICR_WAKER);
		if (!(val & GICR_WAKER_ProcessorSleep))
			return;	/* No PM support in this redistributor */
	}

	while (count--) {
		val = readl_relaxed(rbase + GICR_WAKER);
		if (enable ^ (val & GICR_WAKER_ChildrenAsleep))
			break;
		cpu_relax();
		udelay(1);
	};
	if (!count)
		pr_err_ratelimited("redistributor failed to %s...\n",
				   enable ? "wakeup" : "sleep");
}

/*
 * Routines to disable, enable, EOI and route interrupts
 */
static int gic_peek_irq(struct irq_data *d, u32 offset)
{
	u32 mask = 1 << (gic_irq(d) % 32);
	void __iomem *base;

	if (gic_irq_in_rdist(d))
		base = gic_data_rdist_sgi_base();
	else
		base = gic_data.dist_base;

	return !!(readl_relaxed(base + offset + (gic_irq(d) / 32) * 4) & mask);
}

static void gic_poke_irq(struct irq_data *d, u32 offset)
{
	u32 mask = 1 << (gic_irq(d) % 32);
	void (*rwp_wait)(void);
	void __iomem *base;

	if (gic_irq_in_rdist(d)) {
		base = gic_data_rdist_sgi_base();
		rwp_wait = gic_redist_wait_for_rwp;
	} else {
		base = gic_data.dist_base;
		rwp_wait = gic_dist_wait_for_rwp;
	}

	writel_relaxed(mask, base + offset + (gic_irq(d) / 32) * 4);
	rwp_wait();
}

static void gic_mask_irq(struct irq_data *d)
{
	gic_poke_irq(d, GICD_ICENABLER);
}

static void gic_eoimode1_mask_irq(struct irq_data *d)
{
	gic_mask_irq(d);
	/*
	 * When masking a forwarded interrupt, make sure it is
	 * deactivated as well.
	 *
	 * This ensures that an interrupt that is getting
	 * disabled/masked will not get "stuck", because there is
	 * noone to deactivate it (guest is being terminated).
	 */
	if (irqd_is_forwarded_to_vcpu(d))
		gic_poke_irq(d, GICD_ICACTIVER);
}

static void gic_unmask_irq(struct irq_data *d)
{
	gic_poke_irq(d, GICD_ISENABLER);
}

static int gic_irq_set_irqchip_state(struct irq_data *d,
				     enum irqchip_irq_state which, bool val)
{
	u32 reg;

	if (d->hwirq >= gic_data.irq_nr) /* PPI/SPI only */
		return -EINVAL;

	switch (which) {
	case IRQCHIP_STATE_PENDING:
		reg = val ? GICD_ISPENDR : GICD_ICPENDR;
		break;

	case IRQCHIP_STATE_ACTIVE:
		reg = val ? GICD_ISACTIVER : GICD_ICACTIVER;
		break;

	case IRQCHIP_STATE_MASKED:
		reg = val ? GICD_ICENABLER : GICD_ISENABLER;
		break;

	default:
		return -EINVAL;
	}

	gic_poke_irq(d, reg);
	return 0;
}

static int gic_irq_get_irqchip_state(struct irq_data *d,
				     enum irqchip_irq_state which, bool *val)
{
	if (d->hwirq >= gic_data.irq_nr) /* PPI/SPI only */
		return -EINVAL;

	switch (which) {
	case IRQCHIP_STATE_PENDING:
		*val = gic_peek_irq(d, GICD_ISPENDR);
		break;

	case IRQCHIP_STATE_ACTIVE:
		*val = gic_peek_irq(d, GICD_ISACTIVER);
		break;

	case IRQCHIP_STATE_MASKED:
		*val = !gic_peek_irq(d, GICD_ISENABLER);
		break;

	default:
		return -EINVAL;
	}

	return 0;
}

static void gic_eoi_irq(struct irq_data *d)
{
	gic_write_eoir(gic_irq(d));
}

static void gic_eoimode1_eoi_irq(struct irq_data *d)
{
	/*
	 * No need to deactivate an LPI, or an interrupt that
	 * is is getting forwarded to a vcpu.
	 */
	if (gic_irq(d) >= 8192 || irqd_is_forwarded_to_vcpu(d))
		return;
	gic_write_dir(gic_irq(d));
}

static int gic_set_type(struct irq_data *d, unsigned int type)
{
	unsigned int irq = gic_irq(d);
	void (*rwp_wait)(void);
	void __iomem *base;

	/* Interrupt configuration for SGIs can't be changed */
	if (irq < 16)
		return -EINVAL;

	/* SPIs have restrictions on the supported types */
	if (irq >= 32 && type != IRQ_TYPE_LEVEL_HIGH &&
			 type != IRQ_TYPE_EDGE_RISING)
		return -EINVAL;

	if (gic_irq_in_rdist(d)) {
		base = gic_data_rdist_sgi_base();
		rwp_wait = gic_redist_wait_for_rwp;
	} else {
		base = gic_data.dist_base;
		rwp_wait = gic_dist_wait_for_rwp;
	}

	return gic_configure_irq(irq, type, base, rwp_wait);
}

static int gic_irq_set_vcpu_affinity(struct irq_data *d, void *vcpu)
{
	if (vcpu)
		irqd_set_forwarded_to_vcpu(d);
	else
		irqd_clr_forwarded_to_vcpu(d);
	return 0;
}

static u64 gic_mpidr_to_affinity(unsigned long mpidr)
{
	u64 aff;

	aff = ((u64)MPIDR_AFFINITY_LEVEL(mpidr, 3) << 32 |
	       MPIDR_AFFINITY_LEVEL(mpidr, 2) << 16 |
	       MPIDR_AFFINITY_LEVEL(mpidr, 1) << 8  |
	       MPIDR_AFFINITY_LEVEL(mpidr, 0));

	return aff;
}

static asmlinkage void __exception_irq_entry gic_handle_irq(struct pt_regs *regs)
{
	u32 irqnr;

	do {
		irqnr = gic_read_iar();

		if (likely(irqnr > 15 && irqnr < 1020) || irqnr >= 8192) {
			int err;

			if (static_key_true(&supports_deactivate))
				gic_write_eoir(irqnr);

			err = handle_domain_irq(gic_data.domain, irqnr, regs);
			if (err) {
				WARN_ONCE(true, "Unexpected interrupt received!\n");
				if (static_key_true(&supports_deactivate)) {
					if (irqnr < 8192)
						gic_write_dir(irqnr);
				} else {
					gic_write_eoir(irqnr);
				}
			}
			continue;
		}
		if (irqnr < 16) {
			gic_write_eoir(irqnr);
			if (static_key_true(&supports_deactivate))
				gic_write_dir(irqnr);
#ifdef CONFIG_SMP
			handle_IPI(irqnr, regs);
#else
			WARN_ONCE(true, "Unexpected SGI received!\n");
#endif
			continue;
		}
	} while (irqnr != ICC_IAR1_EL1_SPURIOUS);
}

static void __init gic_dist_init(void)
{
	unsigned int i;
	u64 affinity;
	void __iomem *base = gic_data.dist_base;

	/* Disable the distributor */
	writel_relaxed(0, base + GICD_CTLR);
	gic_dist_wait_for_rwp();

	gic_dist_config(base, gic_data.irq_nr, gic_dist_wait_for_rwp);

	/* Enable distributor with ARE, Group1 */
	writel_relaxed(GICD_CTLR_ARE_NS | GICD_CTLR_ENABLE_G1A | GICD_CTLR_ENABLE_G1,
		       base + GICD_CTLR);

	/*
	 * Set all global interrupts to the boot CPU only. ARE must be
	 * enabled.
	 */
	affinity = gic_mpidr_to_affinity(cpu_logical_map(smp_processor_id()));
	for (i = 32; i < gic_data.irq_nr; i++)
		gic_write_irouter(affinity, base + GICD_IROUTER + i * 8);
}

static int gic_populate_rdist(void)
{
	unsigned long mpidr = cpu_logical_map(smp_processor_id());
	u64 typer;
	u32 aff;
	int i;

	/*
	 * Convert affinity to a 32bit value that can be matched to
	 * GICR_TYPER bits [63:32].
	 */
	aff = (MPIDR_AFFINITY_LEVEL(mpidr, 3) << 24 |
	       MPIDR_AFFINITY_LEVEL(mpidr, 2) << 16 |
	       MPIDR_AFFINITY_LEVEL(mpidr, 1) << 8 |
	       MPIDR_AFFINITY_LEVEL(mpidr, 0));

	for (i = 0; i < gic_data.nr_redist_regions; i++) {
		void __iomem *ptr = gic_data.redist_regions[i].redist_base;
		u32 reg;

		reg = readl_relaxed(ptr + GICR_PIDR2) & GIC_PIDR2_ARCH_MASK;
		if (reg != GIC_PIDR2_ARCH_GICv3 &&
		    reg != GIC_PIDR2_ARCH_GICv4) { /* We're in trouble... */
			pr_warn("No redistributor present @%p\n", ptr);
			break;
		}

		do {
			typer = gic_read_typer(ptr + GICR_TYPER);
			if ((typer >> 32) == aff) {
				u64 offset = ptr - gic_data.redist_regions[i].redist_base;
				gic_data_rdist_rd_base() = ptr;
				gic_data_rdist()->phys_base = gic_data.redist_regions[i].phys_base + offset;
				pr_info("CPU%d: found redistributor %lx region %d:%pa\n",
					smp_processor_id(), mpidr, i,
					&gic_data_rdist()->phys_base);
				return 0;
			}

			if (gic_data.redist_regions[i].single_redist)
				break;

			if (gic_data.redist_stride) {
				ptr += gic_data.redist_stride;
			} else {
				ptr += SZ_64K * 2; /* Skip RD_base + SGI_base */
				if (typer & GICR_TYPER_VLPIS)
					ptr += SZ_64K * 2; /* Skip VLPI_base + reserved page */
			}
		} while (!(typer & GICR_TYPER_LAST));
	}

	/* We couldn't even deal with ourselves... */
	WARN(true, "CPU%d: mpidr %lx has no re-distributor!\n",
	     smp_processor_id(), mpidr);
	return -ENODEV;
}

static void gic_cpu_sys_reg_init(void)
{
	/*
	 * Need to check that the SRE bit has actually been set. If
	 * not, it means that SRE is disabled at EL2. We're going to
	 * die painfully, and there is nothing we can do about it.
	 *
	 * Kindly inform the luser.
	 */
	if (!gic_enable_sre())
		pr_err("GIC: unable to set SRE (disabled at EL2), panic ahead\n");

	/* Set priority mask register */
	gic_write_pmr(DEFAULT_PMR_VALUE);

	if (static_key_true(&supports_deactivate)) {
		/* EOI drops priority only (mode 1) */
		gic_write_ctlr(ICC_CTLR_EL1_EOImode_drop);
	} else {
		/* EOI deactivates interrupt too (mode 0) */
		gic_write_ctlr(ICC_CTLR_EL1_EOImode_drop_dir);
	}

	/* ... and let's hit the road... */
	gic_write_grpen1(1);
}

static int gic_dist_supports_lpis(void)
{
	return !!(readl_relaxed(gic_data.dist_base + GICD_TYPER) & GICD_TYPER_LPIS);
}

static void gic_cpu_init(void)
{
	void __iomem *rbase;

	/* Register ourselves with the rest of the world */
	if (gic_populate_rdist())
		return;

	gic_enable_redist(true);

	rbase = gic_data_rdist_sgi_base();

	gic_cpu_config(rbase, gic_redist_wait_for_rwp);

	/* Give LPIs a spin */
	if (IS_ENABLED(CONFIG_ARM_GIC_V3_ITS) && gic_dist_supports_lpis())
		its_cpu_init();

	/* initialise system registers */
	gic_cpu_sys_reg_init();
}

#ifdef CONFIG_SMP
static int gic_secondary_init(struct notifier_block *nfb,
			      unsigned long action, void *hcpu)
{
	if (action == CPU_STARTING || action == CPU_STARTING_FROZEN)
		gic_cpu_init();
	return NOTIFY_OK;
}

/*
 * Notifier for enabling the GIC CPU interface. Set an arbitrarily high
 * priority because the GIC needs to be up before the ARM generic timers.
 */
static struct notifier_block gic_cpu_notifier = {
	.notifier_call = gic_secondary_init,
	.priority = 100,
};

static u16 gic_compute_target_list(int *base_cpu, const struct cpumask *mask,
				   unsigned long cluster_id)
{
	int cpu = *base_cpu;
	unsigned long mpidr = cpu_logical_map(cpu);
	u16 tlist = 0;

	while (cpu < nr_cpu_ids) {
		/*
		 * If we ever get a cluster of more than 16 CPUs, just
		 * scream and skip that CPU.
		 */
		if (WARN_ON((mpidr & 0xff) >= 16))
			goto out;

		tlist |= 1 << (mpidr & 0xf);

		cpu = cpumask_next(cpu, mask);
		if (cpu >= nr_cpu_ids)
			goto out;

		mpidr = cpu_logical_map(cpu);

		if (cluster_id != (mpidr & ~0xffUL)) {
			cpu--;
			goto out;
		}
	}
out:
	*base_cpu = cpu;
	return tlist;
}

#define MPIDR_TO_SGI_AFFINITY(cluster_id, level) \
	(MPIDR_AFFINITY_LEVEL(cluster_id, level) \
		<< ICC_SGI1R_AFFINITY_## level ##_SHIFT)

static void gic_send_sgi(u64 cluster_id, u16 tlist, unsigned int irq)
{
	u64 val;

	val = (MPIDR_TO_SGI_AFFINITY(cluster_id, 3)	|
	       MPIDR_TO_SGI_AFFINITY(cluster_id, 2)	|
	       irq << ICC_SGI1R_SGI_ID_SHIFT		|
	       MPIDR_TO_SGI_AFFINITY(cluster_id, 1)	|
	       tlist << ICC_SGI1R_TARGET_LIST_SHIFT);

	pr_debug("CPU%d: ICC_SGI1R_EL1 %llx\n", smp_processor_id(), val);
	gic_write_sgi1r(val);
}

static void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
{
	int cpu;

	if (WARN_ON(irq >= 16))
		return;

	/*
	 * Ensure that stores to Normal memory are visible to the
	 * other CPUs before issuing the IPI.
	 */
	smp_wmb();

	for_each_cpu(cpu, mask) {
		unsigned long cluster_id = cpu_logical_map(cpu) & ~0xffUL;
		u16 tlist;

		tlist = gic_compute_target_list(&cpu, mask, cluster_id);
		gic_send_sgi(cluster_id, tlist, irq);
	}

	/* Force the above writes to ICC_SGI1R_EL1 to be executed */
	isb();
}

static void gic_smp_init(void)
{
	set_smp_cross_call(gic_raise_softirq);
	register_cpu_notifier(&gic_cpu_notifier);
}

static int gic_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
			    bool force)
{
	unsigned int cpu = cpumask_any_and(mask_val, cpu_online_mask);
	void __iomem *reg;
	int enabled;
	u64 val;

	if (gic_irq_in_rdist(d))
		return -EINVAL;

	/* If interrupt was enabled, disable it first */
	enabled = gic_peek_irq(d, GICD_ISENABLER);
	if (enabled)
		gic_mask_irq(d);

	reg = gic_dist_base(d) + GICD_IROUTER + (gic_irq(d) * 8);
	val = gic_mpidr_to_affinity(cpu_logical_map(cpu));

	gic_write_irouter(val, reg);

	/*
	 * If the interrupt was enabled, enabled it again. Otherwise,
	 * just wait for the distributor to have digested our changes.
	 */
	if (enabled)
		gic_unmask_irq(d);
	else
		gic_dist_wait_for_rwp();

	return IRQ_SET_MASK_OK_DONE;
}
#else
#define gic_set_affinity	NULL
#define gic_smp_init()		do { } while(0)
#endif

#ifdef CONFIG_CPU_PM
static int gic_cpu_pm_notifier(struct notifier_block *self,
			       unsigned long cmd, void *v)
{
	if (cmd == CPU_PM_EXIT) {
		gic_enable_redist(true);
		gic_cpu_sys_reg_init();
	} else if (cmd == CPU_PM_ENTER) {
		gic_write_grpen1(0);
		gic_enable_redist(false);
	}
	return NOTIFY_OK;
}

static struct notifier_block gic_cpu_pm_notifier_block = {
	.notifier_call = gic_cpu_pm_notifier,
};

static void gic_cpu_pm_init(void)
{
	cpu_pm_register_notifier(&gic_cpu_pm_notifier_block);
}

#else
static inline void gic_cpu_pm_init(void) { }
#endif /* CONFIG_CPU_PM */

static struct irq_chip gic_chip = {
	.name			= "GICv3",
	.irq_mask		= gic_mask_irq,
	.irq_unmask		= gic_unmask_irq,
	.irq_eoi		= gic_eoi_irq,
	.irq_set_type		= gic_set_type,
	.irq_set_affinity	= gic_set_affinity,
	.irq_get_irqchip_state	= gic_irq_get_irqchip_state,
	.irq_set_irqchip_state	= gic_irq_set_irqchip_state,
	.flags			= IRQCHIP_SET_TYPE_MASKED,
};

static struct irq_chip gic_eoimode1_chip = {
	.name			= "GICv3",
	.irq_mask		= gic_eoimode1_mask_irq,
	.irq_unmask		= gic_unmask_irq,
	.irq_eoi		= gic_eoimode1_eoi_irq,
	.irq_set_type		= gic_set_type,
	.irq_set_affinity	= gic_set_affinity,
	.irq_get_irqchip_state	= gic_irq_get_irqchip_state,
	.irq_set_irqchip_state	= gic_irq_set_irqchip_state,
	.irq_set_vcpu_affinity	= gic_irq_set_vcpu_affinity,
	.flags			= IRQCHIP_SET_TYPE_MASKED,
};

#define GIC_ID_NR		(1U << gic_data.rdists.id_bits)

static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq,
			      irq_hw_number_t hw)
{
	struct irq_chip *chip = &gic_chip;

	if (static_key_true(&supports_deactivate))
		chip = &gic_eoimode1_chip;

	/* SGIs are private to the core kernel */
	if (hw < 16)
		return -EPERM;
	/* Nothing here */
	if (hw >= gic_data.irq_nr && hw < 8192)
		return -EPERM;
	/* Off limits */
	if (hw >= GIC_ID_NR)
		return -EPERM;

	/* PPIs */
	if (hw < 32) {
		irq_set_percpu_devid(irq);
		irq_domain_set_info(d, irq, hw, chip, d->host_data,
				    handle_percpu_devid_irq, NULL, NULL);
		irq_set_status_flags(irq, IRQ_NOAUTOEN);
	}
	/* SPIs */
	if (hw >= 32 && hw < gic_data.irq_nr) {
		irq_domain_set_info(d, irq, hw, chip, d->host_data,
				    handle_fasteoi_irq, NULL, NULL);
		irq_set_probe(irq);
	}
	/* LPIs */
	if (hw >= 8192 && hw < GIC_ID_NR) {
		if (!gic_dist_supports_lpis())
			return -EPERM;
		irq_domain_set_info(d, irq, hw, chip, d->host_data,
				    handle_fasteoi_irq, NULL, NULL);
	}

	return 0;
}

static int gic_irq_domain_translate(struct irq_domain *d,
				    struct irq_fwspec *fwspec,
				    unsigned long *hwirq,
				    unsigned int *type)
{
	if (is_of_node(fwspec->fwnode)) {
		if (fwspec->param_count < 3)
			return -EINVAL;

		switch (fwspec->param[0]) {
		case 0:			/* SPI */
			*hwirq = fwspec->param[1] + 32;
			break;
		case 1:			/* PPI */
			*hwirq = fwspec->param[1] + 16;
			break;
		case GIC_IRQ_TYPE_LPI:	/* LPI */
			*hwirq = fwspec->param[1];
			break;
		default:
			return -EINVAL;
		}

		*type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;
		return 0;
	}

	if (is_fwnode_irqchip(fwspec->fwnode)) {
		if(fwspec->param_count != 2)
			return -EINVAL;

		*hwirq = fwspec->param[0];
		*type = fwspec->param[1];
		return 0;
	}

	return -EINVAL;
}

static int gic_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
				unsigned int nr_irqs, void *arg)
{
	int i, ret;
	irq_hw_number_t hwirq;
	unsigned int type = IRQ_TYPE_NONE;
	struct irq_fwspec *fwspec = arg;

	ret = gic_irq_domain_translate(domain, fwspec, &hwirq, &type);
	if (ret)
		return ret;

	for (i = 0; i < nr_irqs; i++)
		gic_irq_domain_map(domain, virq + i, hwirq + i);

	return 0;
}

static void gic_irq_domain_free(struct irq_domain *domain, unsigned int virq,
				unsigned int nr_irqs)
{
	int i;

	for (i = 0; i < nr_irqs; i++) {
		struct irq_data *d = irq_domain_get_irq_data(domain, virq + i);
		irq_set_handler(virq + i, NULL);
		irq_domain_reset_irq_data(d);
	}
}

static const struct irq_domain_ops gic_irq_domain_ops = {
	.translate = gic_irq_domain_translate,
	.alloc = gic_irq_domain_alloc,
	.free = gic_irq_domain_free,
};

static void gicv3_enable_quirks(void)
{
#ifdef CONFIG_ARM64
	if (cpus_have_cap(ARM64_WORKAROUND_CAVIUM_23154))
		static_branch_enable(&is_cavium_thunderx);
#endif
}

static int __init gic_init_bases(void __iomem *dist_base,
				 struct redist_region *rdist_regs,
				 u32 nr_redist_regions,
				 u64 redist_stride,
				 struct fwnode_handle *handle)
{
	struct device_node *node;
	u32 typer;
	int gic_irqs;
	int err;

	if (!is_hyp_mode_available())
		static_key_slow_dec(&supports_deactivate);

	if (static_key_true(&supports_deactivate))
		pr_info("GIC: Using split EOI/Deactivate mode\n");

	gic_data.dist_base = dist_base;
	gic_data.redist_regions = rdist_regs;
	gic_data.nr_redist_regions = nr_redist_regions;
	gic_data.redist_stride = redist_stride;

	gicv3_enable_quirks();

	/*
	 * Find out how many interrupts are supported.
	 * The GIC only supports up to 1020 interrupt sources (SGI+PPI+SPI)
	 */
	typer = readl_relaxed(gic_data.dist_base + GICD_TYPER);
	gic_data.rdists.id_bits = GICD_TYPER_ID_BITS(typer);
	gic_irqs = GICD_TYPER_IRQS(typer);
	if (gic_irqs > 1020)
		gic_irqs = 1020;
	gic_data.irq_nr = gic_irqs;

	gic_data.domain = irq_domain_create_tree(handle, &gic_irq_domain_ops,
						 &gic_data);
	gic_data.rdists.rdist = alloc_percpu(typeof(*gic_data.rdists.rdist));

	if (WARN_ON(!gic_data.domain) || WARN_ON(!gic_data.rdists.rdist)) {
		err = -ENOMEM;
		goto out_free;
	}

	set_handle_irq(gic_handle_irq);

	node = to_of_node(handle);
	if (IS_ENABLED(CONFIG_ARM_GIC_V3_ITS) && gic_dist_supports_lpis() &&
	    node) /* Temp hack to prevent ITS init for ACPI */
		its_init(node, &gic_data.rdists, gic_data.domain);

	gic_smp_init();
	gic_dist_init();
	gic_cpu_init();
	gic_cpu_pm_init();

	return 0;

out_free:
	if (gic_data.domain)
		irq_domain_remove(gic_data.domain);
	free_percpu(gic_data.rdists.rdist);
	return err;
}

static int __init gic_validate_dist_version(void __iomem *dist_base)
{
	u32 reg = readl_relaxed(dist_base + GICD_PIDR2) & GIC_PIDR2_ARCH_MASK;

	if (reg != GIC_PIDR2_ARCH_GICv3 && reg != GIC_PIDR2_ARCH_GICv4)
		return -ENODEV;

	return 0;
}

static int __init gic_of_init(struct device_node *node, struct device_node *parent)
{
	void __iomem *dist_base;
	struct redist_region *rdist_regs;
	u64 redist_stride;
	u32 nr_redist_regions;
	int err, i;

	dist_base = of_iomap(node, 0);
	if (!dist_base) {
		pr_err("%s: unable to map gic dist registers\n",
			node->full_name);
		return -ENXIO;
	}

	err = gic_validate_dist_version(dist_base);
	if (err) {
		pr_err("%s: no distributor detected, giving up\n",
			node->full_name);
		goto out_unmap_dist;
	}

	if (of_property_read_u32(node, "#redistributor-regions", &nr_redist_regions))
		nr_redist_regions = 1;

	rdist_regs = kzalloc(sizeof(*rdist_regs) * nr_redist_regions, GFP_KERNEL);
	if (!rdist_regs) {
		err = -ENOMEM;
		goto out_unmap_dist;
	}

	for (i = 0; i < nr_redist_regions; i++) {
		struct resource res;
		int ret;

		ret = of_address_to_resource(node, 1 + i, &res);
		rdist_regs[i].redist_base = of_iomap(node, 1 + i);
		if (ret || !rdist_regs[i].redist_base) {
			pr_err("%s: couldn't map region %d\n",
			       node->full_name, i);
			err = -ENODEV;
			goto out_unmap_rdist;
		}
		rdist_regs[i].phys_base = res.start;
	}

	if (of_property_read_u64(node, "redistributor-stride", &redist_stride))
		redist_stride = 0;

	err = gic_init_bases(dist_base, rdist_regs, nr_redist_regions,
			     redist_stride, &node->fwnode);
	if (!err)
		return 0;

out_unmap_rdist:
	for (i = 0; i < nr_redist_regions; i++)
		if (rdist_regs[i].redist_base)
			iounmap(rdist_regs[i].redist_base);
	kfree(rdist_regs);
out_unmap_dist:
	iounmap(dist_base);
	return err;
}

IRQCHIP_DECLARE(gic_v3, "arm,gic-v3", gic_of_init);

#ifdef CONFIG_ACPI
static void __iomem *dist_base;
static struct redist_region *redist_regs __initdata;
static u32 nr_redist_regions __initdata;
static bool single_redist;

static void __init
gic_acpi_register_redist(phys_addr_t phys_base, void __iomem *redist_base)
{
	static int count = 0;

	redist_regs[count].phys_base = phys_base;
	redist_regs[count].redist_base = redist_base;
	redist_regs[count].single_redist = single_redist;
	count++;
}

static int __init
gic_acpi_parse_madt_redist(struct acpi_subtable_header *header,
			   const unsigned long end)
{
	struct acpi_madt_generic_redistributor *redist =
			(struct acpi_madt_generic_redistributor *)header;
	void __iomem *redist_base;

	redist_base = ioremap(redist->base_address, redist->length);
	if (!redist_base) {
		pr_err("Couldn't map GICR region @%llx\n", redist->base_address);
		return -ENOMEM;
	}

	gic_acpi_register_redist(redist->base_address, redist_base);
	return 0;
}

static int __init
gic_acpi_parse_madt_gicc(struct acpi_subtable_header *header,
			 const unsigned long end)
{
	struct acpi_madt_generic_interrupt *gicc =
				(struct acpi_madt_generic_interrupt *)header;
	u32 reg = readl_relaxed(dist_base + GICD_PIDR2) & GIC_PIDR2_ARCH_MASK;
	u32 size = reg == GIC_PIDR2_ARCH_GICv4 ? SZ_64K * 4 : SZ_64K * 2;
	void __iomem *redist_base;

	redist_base = ioremap(gicc->gicr_base_address, size);
	if (!redist_base)
		return -ENOMEM;

	gic_acpi_register_redist(gicc->gicr_base_address, redist_base);
	return 0;
}

static int __init gic_acpi_collect_gicr_base(void)
{
	acpi_tbl_entry_handler redist_parser;
	enum acpi_madt_type type;

	if (single_redist) {
		type = ACPI_MADT_TYPE_GENERIC_INTERRUPT;
		redist_parser = gic_acpi_parse_madt_gicc;
	} else {
		type = ACPI_MADT_TYPE_GENERIC_REDISTRIBUTOR;
		redist_parser = gic_acpi_parse_madt_redist;
	}

	/* Collect redistributor base addresses in GICR entries */
	if (acpi_table_parse_madt(type, redist_parser, 0) > 0)
		return 0;

	pr_info("No valid GICR entries exist\n");
	return -ENODEV;
}

static int __init gic_acpi_match_gicr(struct acpi_subtable_header *header,
				  const unsigned long end)
{
	/* Subtable presence means that redist exists, that's it */
	return 0;
}

static int __init gic_acpi_match_gicc(struct acpi_subtable_header *header,
				      const unsigned long end)
{
	struct acpi_madt_generic_interrupt *gicc =
				(struct acpi_madt_generic_interrupt *)header;

	/*
	 * If GICC is enabled and has valid gicr base address, then it means
	 * GICR base is presented via GICC
	 */
	if ((gicc->flags & ACPI_MADT_ENABLED) && gicc->gicr_base_address)
		return 0;

	return -ENODEV;
}

static int __init gic_acpi_count_gicr_regions(void)
{
	int count;

	/*
	 * Count how many redistributor regions we have. It is not allowed
	 * to mix redistributor description, GICR and GICC subtables have to be
	 * mutually exclusive.
	 */
	count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_REDISTRIBUTOR,
				      gic_acpi_match_gicr, 0);
	if (count > 0) {
		single_redist = false;
		return count;
	}

	count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
				      gic_acpi_match_gicc, 0);
	if (count > 0)
		single_redist = true;

	return count;
}

static bool __init acpi_validate_gic_table(struct acpi_subtable_header *header,
					   struct acpi_probe_entry *ape)
{
	struct acpi_madt_generic_distributor *dist;
	int count;

	dist = (struct acpi_madt_generic_distributor *)header;
	if (dist->version != ape->driver_data)
		return false;

	/* We need to do that exercise anyway, the sooner the better */
	count = gic_acpi_count_gicr_regions();
	if (count <= 0)
		return false;

	nr_redist_regions = count;
	return true;
}

#define ACPI_GICV3_DIST_MEM_SIZE (SZ_64K)

static int __init
gic_acpi_init(struct acpi_subtable_header *header, const unsigned long end)
{
	struct acpi_madt_generic_distributor *dist;
	struct fwnode_handle *domain_handle;
	int i, err;

	/* Get distributor base address */
	dist = (struct acpi_madt_generic_distributor *)header;
	dist_base = ioremap(dist->base_address, ACPI_GICV3_DIST_MEM_SIZE);
	if (!dist_base) {
		pr_err("Unable to map GICD registers\n");
		return -ENOMEM;
	}

	err = gic_validate_dist_version(dist_base);
	if (err) {
		pr_err("No distributor detected at @%p, giving up", dist_base);
		goto out_dist_unmap;
	}

	redist_regs = kzalloc(sizeof(*redist_regs) * nr_redist_regions,
			      GFP_KERNEL);
	if (!redist_regs) {
		err = -ENOMEM;
		goto out_dist_unmap;
	}

	err = gic_acpi_collect_gicr_base();
	if (err)
		goto out_redist_unmap;

	domain_handle = irq_domain_alloc_fwnode(dist_base);
	if (!domain_handle) {
		err = -ENOMEM;
		goto out_redist_unmap;
	}

	err = gic_init_bases(dist_base, redist_regs, nr_redist_regions, 0,
			     domain_handle);
	if (err)
		goto out_fwhandle_free;

	acpi_set_irq_model(ACPI_IRQ_MODEL_GIC, domain_handle);
	return 0;

out_fwhandle_free:
	irq_domain_free_fwnode(domain_handle);
out_redist_unmap:
	for (i = 0; i < nr_redist_regions; i++)
		if (redist_regs[i].redist_base)
			iounmap(redist_regs[i].redist_base);
	kfree(redist_regs);
out_dist_unmap:
	iounmap(dist_base);
	return err;
}
IRQCHIP_ACPI_DECLARE(gic_v3, ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR,
		     acpi_validate_gic_table, ACPI_MADT_GIC_VERSION_V3,
		     gic_acpi_init);
IRQCHIP_ACPI_DECLARE(gic_v4, ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR,
		     acpi_validate_gic_table, ACPI_MADT_GIC_VERSION_V4,
		     gic_acpi_init);
IRQCHIP_ACPI_DECLARE(gic_v3_or_v4, ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR,
		     acpi_validate_gic_table, ACPI_MADT_GIC_VERSION_NONE,
		     gic_acpi_init);
#endif