root/drivers/irqchip/irq-csky-mpintc.c
// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/module.h>
#include <linux/irqdomain.h>
#include <linux/irqchip.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/smp.h>
#include <linux/io.h>
#include <asm/irq.h>
#include <asm/traps.h>
#include <asm/reg_ops.h>

static struct irq_domain *root_domain;
static void __iomem *INTCG_base;
static void __iomem *INTCL_base;

#define IPI_IRQ         15
#define INTC_IRQS       256
#define COMM_IRQ_BASE   32

#define INTCG_SIZE      0x8000
#define INTCL_SIZE      0x1000

#define INTCG_ICTLR     0x0
#define INTCG_CICFGR    0x100
#define INTCG_CIDSTR    0x1000

#define INTCL_PICTLR    0x0
#define INTCL_CFGR      0x14
#define INTCL_SIGR      0x60
#define INTCL_RDYIR     0x6c
#define INTCL_SENR      0xa0
#define INTCL_CENR      0xa4
#define INTCL_CACR      0xb4

static DEFINE_PER_CPU(void __iomem *, intcl_reg);

static unsigned long *__trigger;

#define IRQ_OFFSET(irq) ((irq < COMM_IRQ_BASE) ? irq : (irq - COMM_IRQ_BASE))

#define TRIG_BYTE_OFFSET(i)     ((((i) * 2) / 32) * 4)
#define TRIG_BIT_OFFSET(i)       (((i) * 2) % 32)

#define TRIG_VAL(trigger, irq)  (trigger << TRIG_BIT_OFFSET(IRQ_OFFSET(irq)))
#define TRIG_VAL_MSK(irq)           (~(3 << TRIG_BIT_OFFSET(IRQ_OFFSET(irq))))

#define TRIG_BASE(irq) \
        (TRIG_BYTE_OFFSET(IRQ_OFFSET(irq)) + ((irq < COMM_IRQ_BASE) ? \
        (this_cpu_read(intcl_reg) + INTCL_CFGR) : (INTCG_base + INTCG_CICFGR)))

static DEFINE_SPINLOCK(setup_lock);
static void setup_trigger(unsigned long irq, unsigned long trigger)
{
        unsigned int tmp;

        spin_lock(&setup_lock);

        /* setup trigger */
        tmp = readl_relaxed(TRIG_BASE(irq)) & TRIG_VAL_MSK(irq);

        writel_relaxed(tmp | TRIG_VAL(trigger, irq), TRIG_BASE(irq));

        spin_unlock(&setup_lock);
}

static void csky_mpintc_handler(struct pt_regs *regs)
{
        void __iomem *reg_base = this_cpu_read(intcl_reg);

        generic_handle_domain_irq(root_domain,
                readl_relaxed(reg_base + INTCL_RDYIR));
}

static void csky_mpintc_unmask(struct irq_data *d)
{
        void __iomem *reg_base = this_cpu_read(intcl_reg);

        setup_trigger(d->hwirq, __trigger[d->hwirq]);

        writel_relaxed(d->hwirq, reg_base + INTCL_SENR);
}

static void csky_mpintc_mask(struct irq_data *d)
{
        void __iomem *reg_base = this_cpu_read(intcl_reg);

        writel_relaxed(d->hwirq, reg_base + INTCL_CENR);
}

static void csky_mpintc_eoi(struct irq_data *d)
{
        void __iomem *reg_base = this_cpu_read(intcl_reg);

        writel_relaxed(d->hwirq, reg_base + INTCL_CACR);
}

static int csky_mpintc_set_type(struct irq_data *d, unsigned int type)
{
        switch (type & IRQ_TYPE_SENSE_MASK) {
        case IRQ_TYPE_LEVEL_HIGH:
                __trigger[d->hwirq] = 0;
                break;
        case IRQ_TYPE_LEVEL_LOW:
                __trigger[d->hwirq] = 1;
                break;
        case IRQ_TYPE_EDGE_RISING:
                __trigger[d->hwirq] = 2;
                break;
        case IRQ_TYPE_EDGE_FALLING:
                __trigger[d->hwirq] = 3;
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

#ifdef CONFIG_SMP
static int csky_irq_set_affinity(struct irq_data *d,
                                 const struct cpumask *mask_val,
                                 bool force)
{
        unsigned int cpu;
        unsigned int offset = 4 * (d->hwirq - COMM_IRQ_BASE);

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

        if (cpu >= nr_cpu_ids)
                return -EINVAL;

        /*
         * The csky,mpintc could support auto irq deliver, but it only
         * could deliver external irq to one cpu or all cpus. So it
         * doesn't support deliver external irq to a group of cpus
         * with cpu_mask.
         * SO we only use auto deliver mode when affinity mask_val is
         * equal to cpu_present_mask.
         *
         */
        if (cpumask_equal(mask_val, cpu_present_mask))
                cpu = 0;
        else
                cpu |= BIT(31);

        writel_relaxed(cpu, INTCG_base + INTCG_CIDSTR + offset);

        irq_data_update_effective_affinity(d, cpumask_of(cpu));

        return IRQ_SET_MASK_OK_DONE;
}
#endif

static struct irq_chip csky_irq_chip = {
        .name           = "C-SKY SMP Intc",
        .irq_eoi        = csky_mpintc_eoi,
        .irq_unmask     = csky_mpintc_unmask,
        .irq_mask       = csky_mpintc_mask,
        .irq_set_type   = csky_mpintc_set_type,
#ifdef CONFIG_SMP
        .irq_set_affinity = csky_irq_set_affinity,
#endif
};

static int csky_irqdomain_map(struct irq_domain *d, unsigned int irq,
                              irq_hw_number_t hwirq)
{
        if (hwirq < COMM_IRQ_BASE) {
                irq_set_percpu_devid(irq);
                irq_set_chip_and_handler(irq, &csky_irq_chip,
                                         handle_percpu_irq);
        } else {
                irq_set_chip_and_handler(irq, &csky_irq_chip,
                                         handle_fasteoi_irq);
        }

        return 0;
}

static int csky_irq_domain_xlate_cells(struct irq_domain *d,
                struct device_node *ctrlr, const u32 *intspec,
                unsigned int intsize, unsigned long *out_hwirq,
                unsigned int *out_type)
{
        if (WARN_ON(intsize < 1))
                return -EINVAL;

        *out_hwirq = intspec[0];
        if (intsize > 1)
                *out_type = intspec[1] & IRQ_TYPE_SENSE_MASK;
        else
                *out_type = IRQ_TYPE_LEVEL_HIGH;

        return 0;
}

static const struct irq_domain_ops csky_irqdomain_ops = {
        .map    = csky_irqdomain_map,
        .xlate  = csky_irq_domain_xlate_cells,
};

#ifdef CONFIG_SMP
static void csky_mpintc_send_ipi(const struct cpumask *mask)
{
        void __iomem *reg_base = this_cpu_read(intcl_reg);

        /*
         * INTCL_SIGR[3:0] INTID
         * INTCL_SIGR[8:15] CPUMASK
         */
        writel_relaxed((*cpumask_bits(mask)) << 8 | IPI_IRQ,
                                        reg_base + INTCL_SIGR);
}
#endif

/* C-SKY multi processor interrupt controller */
static int __init
csky_mpintc_init(struct device_node *node, struct device_node *parent)
{
        int ret;
        unsigned int cpu, nr_irq;
#ifdef CONFIG_SMP
        unsigned int ipi_irq;
#endif

        if (parent)
                return 0;

        ret = of_property_read_u32(node, "csky,num-irqs", &nr_irq);
        if (ret < 0)
                nr_irq = INTC_IRQS;

        __trigger  = kcalloc(nr_irq, sizeof(unsigned long), GFP_KERNEL);
        if (__trigger == NULL)
                return -ENXIO;

        if (INTCG_base == NULL) {
                INTCG_base = ioremap(mfcr("cr<31, 14>"),
                                     INTCL_SIZE*nr_cpu_ids + INTCG_SIZE);
                if (INTCG_base == NULL)
                        return -EIO;

                INTCL_base = INTCG_base + INTCG_SIZE;

                writel_relaxed(BIT(0), INTCG_base + INTCG_ICTLR);
        }

        root_domain = irq_domain_create_linear(of_fwnode_handle(node), nr_irq, &csky_irqdomain_ops,
                                            NULL);
        if (!root_domain)
                return -ENXIO;

        /* for every cpu */
        for_each_present_cpu(cpu) {
                per_cpu(intcl_reg, cpu) = INTCL_base + (INTCL_SIZE * cpu);
                writel_relaxed(BIT(0), per_cpu(intcl_reg, cpu) + INTCL_PICTLR);
        }

        set_handle_irq(&csky_mpintc_handler);

#ifdef CONFIG_SMP
        ipi_irq = irq_create_mapping(root_domain, IPI_IRQ);
        if (!ipi_irq)
                return -EIO;

        set_send_ipi(&csky_mpintc_send_ipi, ipi_irq);
#endif

        return 0;
}
IRQCHIP_DECLARE(csky_mpintc, "csky,mpintc", csky_mpintc_init);