root/drivers/irqchip/irq-bcm7038-l1.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Broadcom BCM7038 style Level 1 interrupt controller driver
 *
 * Copyright (C) 2014 Broadcom Corporation
 * Author: Kevin Cernekee
 */

#define pr_fmt(fmt)     KBUILD_MODNAME  ": " fmt

#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/types.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/syscore_ops.h>

#define IRQS_PER_WORD           32
#define REG_BYTES_PER_IRQ_WORD  (sizeof(u32) * 4)
#define MAX_WORDS               8

struct bcm7038_l1_cpu;

struct bcm7038_l1_chip {
        raw_spinlock_t          lock;
        unsigned int            n_words;
        struct irq_domain       *domain;
        struct bcm7038_l1_cpu   *cpus[NR_CPUS];
#ifdef CONFIG_PM_SLEEP
        struct list_head        list;
        u32                     wake_mask[MAX_WORDS];
#endif
        u32                     irq_fwd_mask[MAX_WORDS];
        u8                      affinity[MAX_WORDS * IRQS_PER_WORD];
};

struct bcm7038_l1_cpu {
        void __iomem            *map_base;
        u32                     mask_cache[];
};

/*
 * STATUS/MASK_STATUS/MASK_SET/MASK_CLEAR are packed one right after another:
 *
 * 7038:
 *   0x1000_1400: W0_STATUS
 *   0x1000_1404: W1_STATUS
 *   0x1000_1408: W0_MASK_STATUS
 *   0x1000_140c: W1_MASK_STATUS
 *   0x1000_1410: W0_MASK_SET
 *   0x1000_1414: W1_MASK_SET
 *   0x1000_1418: W0_MASK_CLEAR
 *   0x1000_141c: W1_MASK_CLEAR
 *
 * 7445:
 *   0xf03e_1500: W0_STATUS
 *   0xf03e_1504: W1_STATUS
 *   0xf03e_1508: W2_STATUS
 *   0xf03e_150c: W3_STATUS
 *   0xf03e_1510: W4_STATUS
 *   0xf03e_1514: W0_MASK_STATUS
 *   0xf03e_1518: W1_MASK_STATUS
 *   [...]
 */

static inline unsigned int reg_status(struct bcm7038_l1_chip *intc,
                                      unsigned int word)
{
        return (0 * intc->n_words + word) * sizeof(u32);
}

static inline unsigned int reg_mask_set(struct bcm7038_l1_chip *intc,
                                        unsigned int word)
{
        return (2 * intc->n_words + word) * sizeof(u32);
}

static inline unsigned int reg_mask_clr(struct bcm7038_l1_chip *intc,
                                        unsigned int word)
{
        return (3 * intc->n_words + word) * sizeof(u32);
}

static inline u32 l1_readl(void __iomem *reg)
{
        if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
                return ioread32be(reg);
        else
                return readl(reg);
}

static inline void l1_writel(u32 val, void __iomem *reg)
{
        if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
                iowrite32be(val, reg);
        else
                writel(val, reg);
}

static void bcm7038_l1_irq_handle(struct irq_desc *desc)
{
        struct bcm7038_l1_chip *intc = irq_desc_get_handler_data(desc);
        struct bcm7038_l1_cpu *cpu;
        struct irq_chip *chip = irq_desc_get_chip(desc);
        unsigned int idx;

#if defined(CONFIG_SMP) && defined(CONFIG_MIPS)
        cpu = intc->cpus[cpu_logical_map(smp_processor_id())];
#else
        cpu = intc->cpus[0];
#endif

        chained_irq_enter(chip, desc);

        for (idx = 0; idx < intc->n_words; idx++) {
                int base = idx * IRQS_PER_WORD;
                unsigned long pending, flags;
                int hwirq;

                raw_spin_lock_irqsave(&intc->lock, flags);
                pending = l1_readl(cpu->map_base + reg_status(intc, idx)) &
                          ~cpu->mask_cache[idx];
                raw_spin_unlock_irqrestore(&intc->lock, flags);

                for_each_set_bit(hwirq, &pending, IRQS_PER_WORD)
                        generic_handle_domain_irq(intc->domain, base + hwirq);
        }

        chained_irq_exit(chip, desc);
}

static void __bcm7038_l1_unmask(struct irq_data *d, unsigned int cpu_idx)
{
        struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
        u32 word = d->hwirq / IRQS_PER_WORD;
        u32 mask = BIT(d->hwirq % IRQS_PER_WORD);

        intc->cpus[cpu_idx]->mask_cache[word] &= ~mask;
        l1_writel(mask, intc->cpus[cpu_idx]->map_base +
                        reg_mask_clr(intc, word));
}

static void __bcm7038_l1_mask(struct irq_data *d, unsigned int cpu_idx)
{
        struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
        u32 word = d->hwirq / IRQS_PER_WORD;
        u32 mask = BIT(d->hwirq % IRQS_PER_WORD);

        intc->cpus[cpu_idx]->mask_cache[word] |= mask;
        l1_writel(mask, intc->cpus[cpu_idx]->map_base +
                        reg_mask_set(intc, word));
}

static void bcm7038_l1_unmask(struct irq_data *d)
{
        struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
        unsigned long flags;

        raw_spin_lock_irqsave(&intc->lock, flags);
        __bcm7038_l1_unmask(d, intc->affinity[d->hwirq]);
        raw_spin_unlock_irqrestore(&intc->lock, flags);
}

static void bcm7038_l1_mask(struct irq_data *d)
{
        struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
        unsigned long flags;

        raw_spin_lock_irqsave(&intc->lock, flags);
        __bcm7038_l1_mask(d, intc->affinity[d->hwirq]);
        raw_spin_unlock_irqrestore(&intc->lock, flags);
}

#if defined(CONFIG_MIPS) && defined(CONFIG_SMP)
static int bcm7038_l1_set_affinity(struct irq_data *d,
                                   const struct cpumask *dest,
                                   bool force)
{
        struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
        unsigned long flags;
        irq_hw_number_t hw = d->hwirq;
        u32 word = hw / IRQS_PER_WORD;
        u32 mask = BIT(hw % IRQS_PER_WORD);
        unsigned int first_cpu = cpumask_any_and(dest, cpu_online_mask);
        bool was_disabled;

        raw_spin_lock_irqsave(&intc->lock, flags);

        was_disabled = !!(intc->cpus[intc->affinity[hw]]->mask_cache[word] &
                          mask);
        __bcm7038_l1_mask(d, intc->affinity[hw]);
        intc->affinity[hw] = first_cpu;
        if (!was_disabled)
                __bcm7038_l1_unmask(d, first_cpu);

        raw_spin_unlock_irqrestore(&intc->lock, flags);
        irq_data_update_effective_affinity(d, cpumask_of(first_cpu));

        return 0;
}
#endif

static int bcm7038_l1_init_one(struct device_node *dn, unsigned int idx,
                               struct bcm7038_l1_chip *intc)
{
        struct resource res;
        resource_size_t sz;
        struct bcm7038_l1_cpu *cpu;
        unsigned int i, n_words, parent_irq;
        int ret;

        if (of_address_to_resource(dn, idx, &res))
                return -EINVAL;
        sz = resource_size(&res);
        n_words = sz / REG_BYTES_PER_IRQ_WORD;

        if (n_words > MAX_WORDS)
                return -EINVAL;
        else if (!intc->n_words)
                intc->n_words = n_words;
        else if (intc->n_words != n_words)
                return -EINVAL;

        ret = of_property_read_u32_array(dn , "brcm,int-fwd-mask",
                                         intc->irq_fwd_mask, n_words);
        if (ret != 0 && ret != -EINVAL) {
                /* property exists but has the wrong number of words */
                pr_err("invalid brcm,int-fwd-mask property\n");
                return -EINVAL;
        }

        cpu = intc->cpus[idx] = kzalloc_flex(*cpu, mask_cache, n_words);
        if (!cpu)
                return -ENOMEM;

        cpu->map_base = ioremap(res.start, sz);
        if (!cpu->map_base)
                return -ENOMEM;

        for (i = 0; i < n_words; i++) {
                l1_writel(~intc->irq_fwd_mask[i],
                          cpu->map_base + reg_mask_set(intc, i));
                l1_writel(intc->irq_fwd_mask[i],
                          cpu->map_base + reg_mask_clr(intc, i));
                cpu->mask_cache[i] = ~intc->irq_fwd_mask[i];
        }

        parent_irq = irq_of_parse_and_map(dn, idx);
        if (!parent_irq) {
                pr_err("failed to map parent interrupt %d\n", parent_irq);
                return -EINVAL;
        }

        if (of_property_read_bool(dn, "brcm,irq-can-wake"))
                enable_irq_wake(parent_irq);

        irq_set_chained_handler_and_data(parent_irq, bcm7038_l1_irq_handle,
                                         intc);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
/*
 * We keep a list of bcm7038_l1_chip used for suspend/resume. This hack is
 * used because the struct chip_type suspend/resume hooks are not called
 * unless chip_type is hooked onto a generic_chip. Since this driver does
 * not use generic_chip, we need to manually hook our resume/suspend to
 * syscore_ops.
 */
static LIST_HEAD(bcm7038_l1_intcs_list);
static DEFINE_RAW_SPINLOCK(bcm7038_l1_intcs_lock);

static int bcm7038_l1_suspend(void *data)
{
        struct bcm7038_l1_chip *intc;
        int boot_cpu, word;
        u32 val;

        /* Wakeup interrupt should only come from the boot cpu */
#if defined(CONFIG_SMP) && defined(CONFIG_MIPS)
        boot_cpu = cpu_logical_map(0);
#else
        boot_cpu = 0;
#endif

        list_for_each_entry(intc, &bcm7038_l1_intcs_list, list) {
                for (word = 0; word < intc->n_words; word++) {
                        val = intc->wake_mask[word] | intc->irq_fwd_mask[word];
                        l1_writel(~val,
                                intc->cpus[boot_cpu]->map_base + reg_mask_set(intc, word));
                        l1_writel(val,
                                intc->cpus[boot_cpu]->map_base + reg_mask_clr(intc, word));
                }
        }

        return 0;
}

static void bcm7038_l1_resume(void *data)
{
        struct bcm7038_l1_chip *intc;
        int boot_cpu, word;

#if defined(CONFIG_SMP) && defined(CONFIG_MIPS)
        boot_cpu = cpu_logical_map(0);
#else
        boot_cpu = 0;
#endif

        list_for_each_entry(intc, &bcm7038_l1_intcs_list, list) {
                for (word = 0; word < intc->n_words; word++) {
                        l1_writel(intc->cpus[boot_cpu]->mask_cache[word],
                                intc->cpus[boot_cpu]->map_base + reg_mask_set(intc, word));
                        l1_writel(~intc->cpus[boot_cpu]->mask_cache[word],
                                intc->cpus[boot_cpu]->map_base + reg_mask_clr(intc, word));
                }
        }
}

static const struct syscore_ops bcm7038_l1_syscore_ops = {
        .suspend        = bcm7038_l1_suspend,
        .resume         = bcm7038_l1_resume,
};

static struct syscore bcm7038_l1_syscore = {
        .ops = &bcm7038_l1_syscore_ops,
};

static int bcm7038_l1_set_wake(struct irq_data *d, unsigned int on)
{
        struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
        unsigned long flags;
        u32 word = d->hwirq / IRQS_PER_WORD;
        u32 mask = BIT(d->hwirq % IRQS_PER_WORD);

        raw_spin_lock_irqsave(&intc->lock, flags);
        if (on)
                intc->wake_mask[word] |= mask;
        else
                intc->wake_mask[word] &= ~mask;
        raw_spin_unlock_irqrestore(&intc->lock, flags);

        return 0;
}
#endif

static struct irq_chip bcm7038_l1_irq_chip = {
        .name                   = "bcm7038-l1",
        .irq_mask               = bcm7038_l1_mask,
        .irq_unmask             = bcm7038_l1_unmask,
#if defined(CONFIG_SMP) && defined(CONFIG_MIPS)
        .irq_set_affinity       = bcm7038_l1_set_affinity,
#endif
#ifdef CONFIG_PM_SLEEP
        .irq_set_wake           = bcm7038_l1_set_wake,
#endif
};

static int bcm7038_l1_map(struct irq_domain *d, unsigned int virq,
                          irq_hw_number_t hw_irq)
{
        struct bcm7038_l1_chip *intc = d->host_data;
        u32 mask = BIT(hw_irq % IRQS_PER_WORD);
        u32 word = hw_irq / IRQS_PER_WORD;

        if (intc->irq_fwd_mask[word] & mask)
                return -EPERM;

        irq_set_chip_and_handler(virq, &bcm7038_l1_irq_chip, handle_level_irq);
        irq_set_chip_data(virq, d->host_data);
        irqd_set_single_target(irq_get_irq_data(virq));
        return 0;
}

static const struct irq_domain_ops bcm7038_l1_domain_ops = {
        .xlate                  = irq_domain_xlate_onecell,
        .map                    = bcm7038_l1_map,
};

static int bcm7038_l1_probe(struct platform_device *pdev, struct device_node *parent)
{
        struct device_node *dn = pdev->dev.of_node;
        struct bcm7038_l1_chip *intc;
        int idx, ret;

        intc = kzalloc_obj(*intc);
        if (!intc)
                return -ENOMEM;

        raw_spin_lock_init(&intc->lock);
        for_each_possible_cpu(idx) {
                ret = bcm7038_l1_init_one(dn, idx, intc);
                if (ret < 0) {
                        if (idx)
                                break;
                        pr_err("failed to remap intc L1 registers\n");
                        goto out_free;
                }
        }

        intc->domain = irq_domain_create_linear(of_fwnode_handle(dn), IRQS_PER_WORD * intc->n_words,
                                             &bcm7038_l1_domain_ops,
                                             intc);
        if (!intc->domain) {
                ret = -ENOMEM;
                goto out_unmap;
        }

#ifdef CONFIG_PM_SLEEP
        /* Add bcm7038_l1_chip into a list */
        raw_spin_lock(&bcm7038_l1_intcs_lock);
        list_add_tail(&intc->list, &bcm7038_l1_intcs_list);
        raw_spin_unlock(&bcm7038_l1_intcs_lock);

        if (list_is_singular(&bcm7038_l1_intcs_list))
                register_syscore(&bcm7038_l1_syscore);
#endif

        pr_info("registered BCM7038 L1 intc (%pOF, IRQs: %d)\n",
                dn, IRQS_PER_WORD * intc->n_words);

        return 0;

out_unmap:
        for_each_possible_cpu(idx) {
                struct bcm7038_l1_cpu *cpu = intc->cpus[idx];

                if (cpu) {
                        if (cpu->map_base)
                                iounmap(cpu->map_base);
                        kfree(cpu);
                }
        }
out_free:
        kfree(intc);
        return ret;
}

IRQCHIP_PLATFORM_DRIVER_BEGIN(bcm7038_l1)
IRQCHIP_MATCH("brcm,bcm7038-l1-intc", bcm7038_l1_probe)
IRQCHIP_PLATFORM_DRIVER_END(bcm7038_l1)
MODULE_DESCRIPTION("Broadcom STB 7038-style L1/L2 interrupt controller");
MODULE_LICENSE("GPL v2");