drivers/irqchip/irq-armada-370-xp.c

/*
 * Marvell Armada 370 and Armada XP SoC IRQ handling
 *
 * Copyright (C) 2012 Marvell
 *
 * Lior Amsalem <alior@marvell.com>
 * Gregory CLEMENT <gregory.clement@free-electrons.com>
 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
 * Ben Dooks <ben.dooks@codethink.co.uk>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/bits.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/cpu.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
#include <linux/irqdomain.h>
#include <linux/slab.h>
#include <linux/syscore_ops.h>
#include <linux/msi.h>
#include <linux/types.h>
#include <asm/mach/arch.h>
#include <asm/exception.h>
#include <asm/smp_plat.h>
#include <asm/mach/irq.h>

/*
 * Overall diagram of the Armada XP interrupt controller:
 *
 *    To CPU 0                 To CPU 1
 *
 *       /\                       /\
 *       ||                       ||
 * +---------------+     +---------------+
 * |               |	 |               |
 * |    per-CPU    |	 |    per-CPU    |
 * |  mask/unmask  |	 |  mask/unmask  |
 * |     CPU0      |	 |     CPU1      |
 * |               |	 |               |
 * +---------------+	 +---------------+
 *        /\                       /\
 *        ||                       ||
 *        \\_______________________//
 *                     ||
 *            +-------------------+
 *            |                   |
 *            | Global interrupt  |
 *            |    mask/unmask    |
 *            |                   |
 *            +-------------------+
 *                     /\
 *                     ||
 *               interrupt from
 *                   device
 *
 * The "global interrupt mask/unmask" is modified using the
 * ARMADA_370_XP_INT_SET_ENABLE_OFFS and
 * ARMADA_370_XP_INT_CLEAR_ENABLE_OFFS registers, which are relative
 * to "main_int_base".
 *
 * The "per-CPU mask/unmask" is modified using the
 * ARMADA_370_XP_INT_SET_MASK_OFFS and
 * ARMADA_370_XP_INT_CLEAR_MASK_OFFS registers, which are relative to
 * "per_cpu_int_base". This base address points to a special address,
 * which automatically accesses the registers of the current CPU.
 *
 * The per-CPU mask/unmask can also be adjusted using the global
 * per-interrupt ARMADA_370_XP_INT_SOURCE_CTL register, which we use
 * to configure interrupt affinity.
 *
 * Due to this model, all interrupts need to be mask/unmasked at two
 * different levels: at the global level and at the per-CPU level.
 *
 * This driver takes the following approach to deal with this:
 *
 *  - For global interrupts:
 *
 *    At ->map() time, a global interrupt is unmasked at the per-CPU
 *    mask/unmask level. It is therefore unmasked at this level for
 *    the current CPU, running the ->map() code. This allows to have
 *    the interrupt unmasked at this level in non-SMP
 *    configurations. In SMP configurations, the ->set_affinity()
 *    callback is called, which using the
 *    ARMADA_370_XP_INT_SOURCE_CTL() readjusts the per-CPU mask/unmask
 *    for the interrupt.
 *
 *    The ->mask() and ->unmask() operations only mask/unmask the
 *    interrupt at the "global" level.
 *
 *    So, a global interrupt is enabled at the per-CPU level as soon
 *    as it is mapped. At run time, the masking/unmasking takes place
 *    at the global level.
 *
 *  - For per-CPU interrupts
 *
 *    At ->map() time, a per-CPU interrupt is unmasked at the global
 *    mask/unmask level.
 *
 *    The ->mask() and ->unmask() operations mask/unmask the interrupt
 *    at the per-CPU level.
 *
 *    So, a per-CPU interrupt is enabled at the global level as soon
 *    as it is mapped. At run time, the masking/unmasking takes place
 *    at the per-CPU level.
 */

/* Registers relative to main_int_base */
#define ARMADA_370_XP_INT_CONTROL		(0x00)
#define ARMADA_370_XP_SW_TRIG_INT_OFFS		(0x04)
#define ARMADA_370_XP_INT_SET_ENABLE_OFFS	(0x30)
#define ARMADA_370_XP_INT_CLEAR_ENABLE_OFFS	(0x34)
#define ARMADA_370_XP_INT_SOURCE_CTL(irq)	(0x100 + irq*4)
#define ARMADA_370_XP_INT_SOURCE_CPU_MASK	0xF
#define ARMADA_370_XP_INT_IRQ_FIQ_MASK(cpuid)	((BIT(0) | BIT(8)) << cpuid)

/* Registers relative to per_cpu_int_base */
#define ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS	(0x08)
#define ARMADA_370_XP_IN_DRBEL_MSK_OFFS		(0x0c)
#define ARMADA_375_PPI_CAUSE			(0x10)
#define ARMADA_370_XP_CPU_INTACK_OFFS		(0x44)
#define ARMADA_370_XP_INT_SET_MASK_OFFS		(0x48)
#define ARMADA_370_XP_INT_CLEAR_MASK_OFFS	(0x4C)
#define ARMADA_370_XP_INT_FABRIC_MASK_OFFS	(0x54)
#define ARMADA_370_XP_INT_CAUSE_PERF(cpu)	(1 << cpu)

#define ARMADA_370_XP_MAX_PER_CPU_IRQS		(28)

/* IPI and MSI interrupt definitions for IPI platforms */
#define IPI_DOORBELL_START                      (0)
#define IPI_DOORBELL_END                        (8)
#define IPI_DOORBELL_MASK                       0xFF
#define PCI_MSI_DOORBELL_START                  (16)
#define PCI_MSI_DOORBELL_NR                     (16)
#define PCI_MSI_DOORBELL_END                    (32)
#define PCI_MSI_DOORBELL_MASK                   0xFFFF0000

/* MSI interrupt definitions for non-IPI platforms */
#define PCI_MSI_FULL_DOORBELL_START		0
#define PCI_MSI_FULL_DOORBELL_NR		32
#define PCI_MSI_FULL_DOORBELL_END		32
#define PCI_MSI_FULL_DOORBELL_MASK		GENMASK(31, 0)
#define PCI_MSI_FULL_DOORBELL_SRC0_MASK		GENMASK(15, 0)
#define PCI_MSI_FULL_DOORBELL_SRC1_MASK		GENMASK(31, 16)

static void __iomem *per_cpu_int_base;
static void __iomem *main_int_base;
static struct irq_domain *armada_370_xp_mpic_domain;
static u32 doorbell_mask_reg;
static int parent_irq;
#ifdef CONFIG_PCI_MSI
static struct irq_domain *armada_370_xp_msi_domain;
static struct irq_domain *armada_370_xp_msi_inner_domain;
static DECLARE_BITMAP(msi_used, PCI_MSI_FULL_DOORBELL_NR);
static DEFINE_MUTEX(msi_used_lock);
static phys_addr_t msi_doorbell_addr;
#endif

static inline bool is_ipi_available(void)
{
	/*
	 * We distinguish IPI availability in the IC by the IC not having a
	 * parent irq defined. If a parent irq is defined, there is a parent
	 * interrupt controller (e.g. GIC) that takes care of inter-processor
	 * interrupts.
	 */
	return parent_irq <= 0;
}

static inline u32 msi_doorbell_mask(void)
{
	return is_ipi_available() ? PCI_MSI_DOORBELL_MASK :
				    PCI_MSI_FULL_DOORBELL_MASK;
}

static inline unsigned int msi_doorbell_start(void)
{
	return is_ipi_available() ? PCI_MSI_DOORBELL_START :
				    PCI_MSI_FULL_DOORBELL_START;
}

static inline unsigned int msi_doorbell_size(void)
{
	return is_ipi_available() ? PCI_MSI_DOORBELL_NR :
				    PCI_MSI_FULL_DOORBELL_NR;
}

static inline unsigned int msi_doorbell_end(void)
{
	return is_ipi_available() ? PCI_MSI_DOORBELL_END :
				    PCI_MSI_FULL_DOORBELL_END;
}

static inline bool is_percpu_irq(irq_hw_number_t irq)
{
	if (irq <= ARMADA_370_XP_MAX_PER_CPU_IRQS)
		return true;

	return false;
}

/*
 * In SMP mode:
 * For shared global interrupts, mask/unmask global enable bit
 * For CPU interrupts, mask/unmask the calling CPU's bit
 */
static void armada_370_xp_irq_mask(struct irq_data *d)
{
	irq_hw_number_t hwirq = irqd_to_hwirq(d);

	if (!is_percpu_irq(hwirq))
		writel(hwirq, main_int_base +
				ARMADA_370_XP_INT_CLEAR_ENABLE_OFFS);
	else
		writel(hwirq, per_cpu_int_base +
				ARMADA_370_XP_INT_SET_MASK_OFFS);
}

static void armada_370_xp_irq_unmask(struct irq_data *d)
{
	irq_hw_number_t hwirq = irqd_to_hwirq(d);

	if (!is_percpu_irq(hwirq))
		writel(hwirq, main_int_base +
				ARMADA_370_XP_INT_SET_ENABLE_OFFS);
	else
		writel(hwirq, per_cpu_int_base +
				ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
}

#ifdef CONFIG_PCI_MSI

static struct irq_chip armada_370_xp_msi_irq_chip = {
	.name = "MPIC MSI",
	.irq_mask = pci_msi_mask_irq,
	.irq_unmask = pci_msi_unmask_irq,
};

static struct msi_domain_info armada_370_xp_msi_domain_info = {
	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
		   MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
	.chip	= &armada_370_xp_msi_irq_chip,
};

static void armada_370_xp_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
{
	unsigned int cpu = cpumask_first(irq_data_get_effective_affinity_mask(data));

	msg->address_lo = lower_32_bits(msi_doorbell_addr);
	msg->address_hi = upper_32_bits(msi_doorbell_addr);
	msg->data = BIT(cpu + 8) | (data->hwirq + msi_doorbell_start());
}

static int armada_370_xp_msi_set_affinity(struct irq_data *irq_data,
					  const struct cpumask *mask, bool force)
{
	unsigned int cpu;

	if (!force)
		cpu = cpumask_any_and(mask, cpu_online_mask);
	else
		cpu = cpumask_first(mask);

	if (cpu >= nr_cpu_ids)
		return -EINVAL;

	irq_data_update_effective_affinity(irq_data, cpumask_of(cpu));

	return IRQ_SET_MASK_OK;
}

static struct irq_chip armada_370_xp_msi_bottom_irq_chip = {
	.name			= "MPIC MSI",
	.irq_compose_msi_msg	= armada_370_xp_compose_msi_msg,
	.irq_set_affinity	= armada_370_xp_msi_set_affinity,
};

static int armada_370_xp_msi_alloc(struct irq_domain *domain, unsigned int virq,
				   unsigned int nr_irqs, void *args)
{
	int hwirq, i;

	mutex_lock(&msi_used_lock);
	hwirq = bitmap_find_free_region(msi_used, msi_doorbell_size(),
					order_base_2(nr_irqs));
	mutex_unlock(&msi_used_lock);

	if (hwirq < 0)
		return -ENOSPC;

	for (i = 0; i < nr_irqs; i++) {
		irq_domain_set_info(domain, virq + i, hwirq + i,
				    &armada_370_xp_msi_bottom_irq_chip,
				    domain->host_data, handle_simple_irq,
				    NULL, NULL);
	}

	return 0;
}

static void armada_370_xp_msi_free(struct irq_domain *domain,
				   unsigned int virq, unsigned int nr_irqs)
{
	struct irq_data *d = irq_domain_get_irq_data(domain, virq);

	mutex_lock(&msi_used_lock);
	bitmap_release_region(msi_used, d->hwirq, order_base_2(nr_irqs));
	mutex_unlock(&msi_used_lock);
}

static const struct irq_domain_ops armada_370_xp_msi_domain_ops = {
	.alloc	= armada_370_xp_msi_alloc,
	.free	= armada_370_xp_msi_free,
};

static void armada_370_xp_msi_reenable_percpu(void)
{
	u32 reg;

	/* Enable MSI doorbell mask and combined cpu local interrupt */
	reg = readl(per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
	reg |= msi_doorbell_mask();
	writel(reg, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);

	/* Unmask local doorbell interrupt */
	writel(1, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
}

static int armada_370_xp_msi_init(struct device_node *node,
				  phys_addr_t main_int_phys_base)
{
	msi_doorbell_addr = main_int_phys_base +
		ARMADA_370_XP_SW_TRIG_INT_OFFS;

	armada_370_xp_msi_inner_domain =
		irq_domain_add_linear(NULL, msi_doorbell_size(),
				      &armada_370_xp_msi_domain_ops, NULL);
	if (!armada_370_xp_msi_inner_domain)
		return -ENOMEM;

	armada_370_xp_msi_domain =
		pci_msi_create_irq_domain(of_node_to_fwnode(node),
					  &armada_370_xp_msi_domain_info,
					  armada_370_xp_msi_inner_domain);
	if (!armada_370_xp_msi_domain) {
		irq_domain_remove(armada_370_xp_msi_inner_domain);
		return -ENOMEM;
	}

	armada_370_xp_msi_reenable_percpu();

	/* Unmask low 16 MSI irqs on non-IPI platforms */
	if (!is_ipi_available())
		writel(0, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);

	return 0;
}
#else
static __maybe_unused void armada_370_xp_msi_reenable_percpu(void) {}

static inline int armada_370_xp_msi_init(struct device_node *node,
					 phys_addr_t main_int_phys_base)
{
	return 0;
}
#endif

static void armada_xp_mpic_perf_init(void)
{
	unsigned long cpuid;

	/*
	 * This Performance Counter Overflow interrupt is specific for
	 * Armada 370 and XP. It is not available on Armada 375, 38x and 39x.
	 */
	if (!of_machine_is_compatible("marvell,armada-370-xp"))
		return;

	cpuid = cpu_logical_map(smp_processor_id());

	/* Enable Performance Counter Overflow interrupts */
	writel(ARMADA_370_XP_INT_CAUSE_PERF(cpuid),
	       per_cpu_int_base + ARMADA_370_XP_INT_FABRIC_MASK_OFFS);
}

#ifdef CONFIG_SMP
static struct irq_domain *ipi_domain;

static void armada_370_xp_ipi_mask(struct irq_data *d)
{
	u32 reg;
	reg = readl(per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
	reg &= ~BIT(d->hwirq);
	writel(reg, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
}

static void armada_370_xp_ipi_unmask(struct irq_data *d)
{
	u32 reg;
	reg = readl(per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
	reg |= BIT(d->hwirq);
	writel(reg, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
}

static void armada_370_xp_ipi_send_mask(struct irq_data *d,
					const struct cpumask *mask)
{
	unsigned long map = 0;
	int cpu;

	/* Convert our logical CPU mask into a physical one. */
	for_each_cpu(cpu, mask)
		map |= 1 << cpu_logical_map(cpu);

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

	/* submit softirq */
	writel((map << 8) | d->hwirq, main_int_base +
		ARMADA_370_XP_SW_TRIG_INT_OFFS);
}

static void armada_370_xp_ipi_ack(struct irq_data *d)
{
	writel(~BIT(d->hwirq), per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
}

static struct irq_chip ipi_irqchip = {
	.name		= "IPI",
	.irq_ack	= armada_370_xp_ipi_ack,
	.irq_mask	= armada_370_xp_ipi_mask,
	.irq_unmask	= armada_370_xp_ipi_unmask,
	.ipi_send_mask	= armada_370_xp_ipi_send_mask,
};

static int armada_370_xp_ipi_alloc(struct irq_domain *d,
					 unsigned int virq,
					 unsigned int nr_irqs, void *args)
{
	int i;

	for (i = 0; i < nr_irqs; i++) {
		irq_set_percpu_devid(virq + i);
		irq_domain_set_info(d, virq + i, i, &ipi_irqchip,
				    d->host_data,
				    handle_percpu_devid_irq,
				    NULL, NULL);
	}

	return 0;
}

static void armada_370_xp_ipi_free(struct irq_domain *d,
					 unsigned int virq,
					 unsigned int nr_irqs)
{
	/* Not freeing IPIs */
}

static const struct irq_domain_ops ipi_domain_ops = {
	.alloc	= armada_370_xp_ipi_alloc,
	.free	= armada_370_xp_ipi_free,
};

static void ipi_resume(void)
{
	int i;

	for (i = 0; i < IPI_DOORBELL_END; i++) {
		int irq;

		irq = irq_find_mapping(ipi_domain, i);
		if (irq <= 0)
			continue;
		if (irq_percpu_is_enabled(irq)) {
			struct irq_data *d;
			d = irq_domain_get_irq_data(ipi_domain, irq);
			armada_370_xp_ipi_unmask(d);
		}
	}
}

static __init void armada_xp_ipi_init(struct device_node *node)
{
	int base_ipi;

	ipi_domain = irq_domain_create_linear(of_node_to_fwnode(node),
					      IPI_DOORBELL_END,
					      &ipi_domain_ops, NULL);
	if (WARN_ON(!ipi_domain))
		return;

	irq_domain_update_bus_token(ipi_domain, DOMAIN_BUS_IPI);
	base_ipi = irq_domain_alloc_irqs(ipi_domain, IPI_DOORBELL_END, NUMA_NO_NODE, NULL);
	if (WARN_ON(!base_ipi))
		return;

	set_smp_ipi_range(base_ipi, IPI_DOORBELL_END);
}

static int armada_xp_set_affinity(struct irq_data *d,
				  const struct cpumask *mask_val, bool force)
{
	irq_hw_number_t hwirq = irqd_to_hwirq(d);
	int cpu;

	/* Select a single core from the affinity mask which is online */
	cpu = cpumask_any_and(mask_val, cpu_online_mask);

	atomic_io_modify(main_int_base + ARMADA_370_XP_INT_SOURCE_CTL(hwirq),
			 ARMADA_370_XP_INT_SOURCE_CPU_MASK,
			 BIT(cpu_logical_map(cpu)));

	irq_data_update_effective_affinity(d, cpumask_of(cpu));

	return IRQ_SET_MASK_OK;
}

static void armada_xp_mpic_smp_cpu_init(void)
{
	u32 control;
	int nr_irqs, i;

	control = readl(main_int_base + ARMADA_370_XP_INT_CONTROL);
	nr_irqs = (control >> 2) & 0x3ff;

	for (i = 0; i < nr_irqs; i++)
		writel(i, per_cpu_int_base + ARMADA_370_XP_INT_SET_MASK_OFFS);

	if (!is_ipi_available())
		return;

	/* Disable all IPIs */
	writel(0, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);

	/* Clear pending IPIs */
	writel(0, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);

	/* Unmask IPI interrupt */
	writel(0, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
}

static void armada_xp_mpic_reenable_percpu(void)
{
	unsigned int irq;

	/* Re-enable per-CPU interrupts that were enabled before suspend */
	for (irq = 0; irq < ARMADA_370_XP_MAX_PER_CPU_IRQS; irq++) {
		struct irq_data *data;
		int virq;

		virq = irq_linear_revmap(armada_370_xp_mpic_domain, irq);
		if (virq == 0)
			continue;

		data = irq_get_irq_data(virq);

		if (!irq_percpu_is_enabled(virq))
			continue;

		armada_370_xp_irq_unmask(data);
	}

	if (is_ipi_available())
		ipi_resume();

	armada_370_xp_msi_reenable_percpu();
}

static int armada_xp_mpic_starting_cpu(unsigned int cpu)
{
	armada_xp_mpic_perf_init();
	armada_xp_mpic_smp_cpu_init();
	armada_xp_mpic_reenable_percpu();
	return 0;
}

static int mpic_cascaded_starting_cpu(unsigned int cpu)
{
	armada_xp_mpic_perf_init();
	armada_xp_mpic_reenable_percpu();
	enable_percpu_irq(parent_irq, IRQ_TYPE_NONE);
	return 0;
}
#else
static void armada_xp_mpic_smp_cpu_init(void) {}
static void ipi_resume(void) {}
#endif

static struct irq_chip armada_370_xp_irq_chip = {
	.name		= "MPIC",
	.irq_mask       = armada_370_xp_irq_mask,
	.irq_mask_ack   = armada_370_xp_irq_mask,
	.irq_unmask     = armada_370_xp_irq_unmask,
#ifdef CONFIG_SMP
	.irq_set_affinity = armada_xp_set_affinity,
#endif
	.flags		= IRQCHIP_SKIP_SET_WAKE | IRQCHIP_MASK_ON_SUSPEND,
};

static int armada_370_xp_mpic_irq_map(struct irq_domain *h,
				      unsigned int virq, irq_hw_number_t hw)
{
	/* IRQs 0 and 1 cannot be mapped, they are handled internally */
	if (hw <= 1)
		return -EINVAL;

	armada_370_xp_irq_mask(irq_get_irq_data(virq));
	if (!is_percpu_irq(hw))
		writel(hw, per_cpu_int_base +
			ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
	else
		writel(hw, main_int_base + ARMADA_370_XP_INT_SET_ENABLE_OFFS);
	irq_set_status_flags(virq, IRQ_LEVEL);

	if (is_percpu_irq(hw)) {
		irq_set_percpu_devid(virq);
		irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
					handle_percpu_devid_irq);
	} else {
		irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
					handle_level_irq);
		irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(virq)));
	}
	irq_set_probe(virq);

	return 0;
}

static const struct irq_domain_ops armada_370_xp_mpic_irq_ops = {
	.map = armada_370_xp_mpic_irq_map,
	.xlate = irq_domain_xlate_onecell,
};

#ifdef CONFIG_PCI_MSI
static void armada_370_xp_handle_msi_irq(struct pt_regs *regs, bool is_chained)
{
	u32 msimask, msinr;

	msimask = readl_relaxed(per_cpu_int_base +
				ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
	msimask &= msi_doorbell_mask();

	writel(~msimask, per_cpu_int_base +
	       ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);

	for (msinr = msi_doorbell_start();
	     msinr < msi_doorbell_end(); msinr++) {
		unsigned int irq;

		if (!(msimask & BIT(msinr)))
			continue;

		irq = msinr - msi_doorbell_start();

		generic_handle_domain_irq(armada_370_xp_msi_inner_domain, irq);
	}
}
#else
static void armada_370_xp_handle_msi_irq(struct pt_regs *r, bool b) {}
#endif

static void armada_370_xp_mpic_handle_cascade_irq(struct irq_desc *desc)
{
	struct irq_chip *chip = irq_desc_get_chip(desc);
	unsigned long irqmap, irqn, irqsrc, cpuid;

	chained_irq_enter(chip, desc);

	irqmap = readl_relaxed(per_cpu_int_base + ARMADA_375_PPI_CAUSE);
	cpuid = cpu_logical_map(smp_processor_id());

	for_each_set_bit(irqn, &irqmap, BITS_PER_LONG) {
		irqsrc = readl_relaxed(main_int_base +
				       ARMADA_370_XP_INT_SOURCE_CTL(irqn));

		/* Check if the interrupt is not masked on current CPU.
		 * Test IRQ (0-1) and FIQ (8-9) mask bits.
		 */
		if (!(irqsrc & ARMADA_370_XP_INT_IRQ_FIQ_MASK(cpuid)))
			continue;

		if (irqn == 0 || irqn == 1) {
			armada_370_xp_handle_msi_irq(NULL, true);
			continue;
		}

		generic_handle_domain_irq(armada_370_xp_mpic_domain, irqn);
	}

	chained_irq_exit(chip, desc);
}

static void __exception_irq_entry
armada_370_xp_handle_irq(struct pt_regs *regs)
{
	u32 irqstat, irqnr;

	do {
		irqstat = readl_relaxed(per_cpu_int_base +
					ARMADA_370_XP_CPU_INTACK_OFFS);
		irqnr = irqstat & 0x3FF;

		if (irqnr > 1022)
			break;

		if (irqnr > 1) {
			generic_handle_domain_irq(armada_370_xp_mpic_domain,
						  irqnr);
			continue;
		}

		/* MSI handling */
		if (irqnr == 1)
			armada_370_xp_handle_msi_irq(regs, false);

#ifdef CONFIG_SMP
		/* IPI Handling */
		if (irqnr == 0) {
			unsigned long ipimask;
			int ipi;

			ipimask = readl_relaxed(per_cpu_int_base +
						ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS)
				& IPI_DOORBELL_MASK;

			for_each_set_bit(ipi, &ipimask, IPI_DOORBELL_END)
				generic_handle_domain_irq(ipi_domain, ipi);
		}
#endif

	} while (1);
}

static int armada_370_xp_mpic_suspend(void)
{
	doorbell_mask_reg = readl(per_cpu_int_base +
				  ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
	return 0;
}

static void armada_370_xp_mpic_resume(void)
{
	bool src0, src1;
	int nirqs;
	irq_hw_number_t irq;

	/* Re-enable interrupts */
	nirqs = (readl(main_int_base + ARMADA_370_XP_INT_CONTROL) >> 2) & 0x3ff;
	for (irq = 0; irq < nirqs; irq++) {
		struct irq_data *data;
		int virq;

		virq = irq_linear_revmap(armada_370_xp_mpic_domain, irq);
		if (virq == 0)
			continue;

		data = irq_get_irq_data(virq);

		if (!is_percpu_irq(irq)) {
			/* Non per-CPU interrupts */
			writel(irq, per_cpu_int_base +
			       ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
			if (!irqd_irq_disabled(data))
				armada_370_xp_irq_unmask(data);
		} else {
			/* Per-CPU interrupts */
			writel(irq, main_int_base +
			       ARMADA_370_XP_INT_SET_ENABLE_OFFS);

			/*
			 * Re-enable on the current CPU,
			 * armada_xp_mpic_reenable_percpu() will take
			 * care of secondary CPUs when they come up.
			 */
			if (irq_percpu_is_enabled(virq))
				armada_370_xp_irq_unmask(data);
		}
	}

	/* Reconfigure doorbells for IPIs and MSIs */
	writel(doorbell_mask_reg,
	       per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);

	if (is_ipi_available()) {
		src0 = doorbell_mask_reg & IPI_DOORBELL_MASK;
		src1 = doorbell_mask_reg & PCI_MSI_DOORBELL_MASK;
	} else {
		src0 = doorbell_mask_reg & PCI_MSI_FULL_DOORBELL_SRC0_MASK;
		src1 = doorbell_mask_reg & PCI_MSI_FULL_DOORBELL_SRC1_MASK;
	}

	if (src0)
		writel(0, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
	if (src1)
		writel(1, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);

	if (is_ipi_available())
		ipi_resume();
}

static struct syscore_ops armada_370_xp_mpic_syscore_ops = {
	.suspend	= armada_370_xp_mpic_suspend,
	.resume		= armada_370_xp_mpic_resume,
};

static int __init armada_370_xp_mpic_of_init(struct device_node *node,
					     struct device_node *parent)
{
	struct resource main_int_res, per_cpu_int_res;
	int nr_irqs, i;
	u32 control;

	BUG_ON(of_address_to_resource(node, 0, &main_int_res));
	BUG_ON(of_address_to_resource(node, 1, &per_cpu_int_res));

	BUG_ON(!request_mem_region(main_int_res.start,
				   resource_size(&main_int_res),
				   node->full_name));
	BUG_ON(!request_mem_region(per_cpu_int_res.start,
				   resource_size(&per_cpu_int_res),
				   node->full_name));

	main_int_base = ioremap(main_int_res.start,
				resource_size(&main_int_res));
	BUG_ON(!main_int_base);

	per_cpu_int_base = ioremap(per_cpu_int_res.start,
				   resource_size(&per_cpu_int_res));
	BUG_ON(!per_cpu_int_base);

	control = readl(main_int_base + ARMADA_370_XP_INT_CONTROL);
	nr_irqs = (control >> 2) & 0x3ff;

	for (i = 0; i < nr_irqs; i++)
		writel(i, main_int_base + ARMADA_370_XP_INT_CLEAR_ENABLE_OFFS);

	armada_370_xp_mpic_domain =
		irq_domain_add_linear(node, nr_irqs,
				&armada_370_xp_mpic_irq_ops, NULL);
	BUG_ON(!armada_370_xp_mpic_domain);
	irq_domain_update_bus_token(armada_370_xp_mpic_domain, DOMAIN_BUS_WIRED);

	/*
	 * Initialize parent_irq before calling any other functions, since it is
	 * used to distinguish between IPI and non-IPI platforms.
	 */
	parent_irq = irq_of_parse_and_map(node, 0);

	/* Setup for the boot CPU */
	armada_xp_mpic_perf_init();
	armada_xp_mpic_smp_cpu_init();

	armada_370_xp_msi_init(node, main_int_res.start);

	if (parent_irq <= 0) {
		irq_set_default_host(armada_370_xp_mpic_domain);
		set_handle_irq(armada_370_xp_handle_irq);
#ifdef CONFIG_SMP
		armada_xp_ipi_init(node);
		cpuhp_setup_state_nocalls(CPUHP_AP_IRQ_ARMADA_XP_STARTING,
					  "irqchip/armada/ipi:starting",
					  armada_xp_mpic_starting_cpu, NULL);
#endif
	} else {
#ifdef CONFIG_SMP
		cpuhp_setup_state_nocalls(CPUHP_AP_IRQ_ARMADA_XP_STARTING,
					  "irqchip/armada/cascade:starting",
					  mpic_cascaded_starting_cpu, NULL);
#endif
		irq_set_chained_handler(parent_irq,
					armada_370_xp_mpic_handle_cascade_irq);
	}

	register_syscore_ops(&armada_370_xp_mpic_syscore_ops);

	return 0;
}

IRQCHIP_DECLARE(armada_370_xp_mpic, "marvell,mpic", armada_370_xp_mpic_of_init);