root/drivers/irqchip/irq-stm32-exti.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) Maxime Coquelin 2015
 * Copyright (C) STMicroelectronics 2017-2024
 * Author:  Maxime Coquelin <mcoquelin.stm32@gmail.com>
 */

#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdomain.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>

#define IRQS_PER_BANK                   32

struct stm32_exti_bank {
        u32 imr_ofst;
        u32 emr_ofst;
        u32 rtsr_ofst;
        u32 ftsr_ofst;
        u32 swier_ofst;
        u32 rpr_ofst;
};

struct stm32_exti_drv_data {
        const struct stm32_exti_bank **exti_banks;
        const u8 *desc_irqs;
        u32 bank_nr;
};

struct stm32_exti_chip_data {
        struct stm32_exti_host_data *host_data;
        const struct stm32_exti_bank *reg_bank;
        u32 wake_active;
        u32 mask_cache;
        u32 rtsr_cache;
        u32 ftsr_cache;
        u32 event_reserved;
};

struct stm32_exti_host_data {
        void __iomem *base;
        struct device *dev;
        struct stm32_exti_chip_data *chips_data;
        const struct stm32_exti_drv_data *drv_data;
};

static const struct stm32_exti_bank stm32f4xx_exti_b1 = {
        .imr_ofst       = 0x00,
        .emr_ofst       = 0x04,
        .rtsr_ofst      = 0x08,
        .ftsr_ofst      = 0x0C,
        .swier_ofst     = 0x10,
        .rpr_ofst       = 0x14,
};

static const struct stm32_exti_bank *stm32f4xx_exti_banks[] = {
        &stm32f4xx_exti_b1,
};

static const struct stm32_exti_drv_data stm32f4xx_drv_data = {
        .exti_banks = stm32f4xx_exti_banks,
        .bank_nr = ARRAY_SIZE(stm32f4xx_exti_banks),
};

static const struct stm32_exti_bank stm32h7xx_exti_b1 = {
        .imr_ofst       = 0x80,
        .emr_ofst       = 0x84,
        .rtsr_ofst      = 0x00,
        .ftsr_ofst      = 0x04,
        .swier_ofst     = 0x08,
        .rpr_ofst       = 0x88,
};

static const struct stm32_exti_bank stm32h7xx_exti_b2 = {
        .imr_ofst       = 0x90,
        .emr_ofst       = 0x94,
        .rtsr_ofst      = 0x20,
        .ftsr_ofst      = 0x24,
        .swier_ofst     = 0x28,
        .rpr_ofst       = 0x98,
};

static const struct stm32_exti_bank stm32h7xx_exti_b3 = {
        .imr_ofst       = 0xA0,
        .emr_ofst       = 0xA4,
        .rtsr_ofst      = 0x40,
        .ftsr_ofst      = 0x44,
        .swier_ofst     = 0x48,
        .rpr_ofst       = 0xA8,
};

static const struct stm32_exti_bank *stm32h7xx_exti_banks[] = {
        &stm32h7xx_exti_b1,
        &stm32h7xx_exti_b2,
        &stm32h7xx_exti_b3,
};

static const struct stm32_exti_drv_data stm32h7xx_drv_data = {
        .exti_banks = stm32h7xx_exti_banks,
        .bank_nr = ARRAY_SIZE(stm32h7xx_exti_banks),
};

static unsigned long stm32_exti_pending(struct irq_chip_generic *gc)
{
        struct stm32_exti_chip_data *chip_data = gc->private;
        const struct stm32_exti_bank *stm32_bank = chip_data->reg_bank;

        return irq_reg_readl(gc, stm32_bank->rpr_ofst);
}

static void stm32_irq_handler(struct irq_desc *desc)
{
        struct irq_domain *domain = irq_desc_get_handler_data(desc);
        struct irq_chip *chip = irq_desc_get_chip(desc);
        unsigned int nbanks = domain->gc->num_chips;
        struct irq_chip_generic *gc;
        unsigned long pending;
        int n, i, irq_base = 0;

        chained_irq_enter(chip, desc);

        for (i = 0; i < nbanks; i++, irq_base += IRQS_PER_BANK) {
                gc = irq_get_domain_generic_chip(domain, irq_base);

                while ((pending = stm32_exti_pending(gc))) {
                        for_each_set_bit(n, &pending, IRQS_PER_BANK)
                                generic_handle_domain_irq(domain, irq_base + n);
                }
        }

        chained_irq_exit(chip, desc);
}

static int stm32_exti_set_type(struct irq_data *d,
                               unsigned int type, u32 *rtsr, u32 *ftsr)
{
        u32 mask = BIT(d->hwirq % IRQS_PER_BANK);

        switch (type) {
        case IRQ_TYPE_EDGE_RISING:
                *rtsr |= mask;
                *ftsr &= ~mask;
                break;
        case IRQ_TYPE_EDGE_FALLING:
                *rtsr &= ~mask;
                *ftsr |= mask;
                break;
        case IRQ_TYPE_EDGE_BOTH:
                *rtsr |= mask;
                *ftsr |= mask;
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static int stm32_irq_set_type(struct irq_data *d, unsigned int type)
{
        struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
        struct stm32_exti_chip_data *chip_data = gc->private;
        const struct stm32_exti_bank *stm32_bank = chip_data->reg_bank;
        u32 rtsr, ftsr;
        int err;

        guard(raw_spinlock)(&gc->lock);

        rtsr = irq_reg_readl(gc, stm32_bank->rtsr_ofst);
        ftsr = irq_reg_readl(gc, stm32_bank->ftsr_ofst);

        err = stm32_exti_set_type(d, type, &rtsr, &ftsr);
        if (err)
                return err;

        irq_reg_writel(gc, rtsr, stm32_bank->rtsr_ofst);
        irq_reg_writel(gc, ftsr, stm32_bank->ftsr_ofst);
        return 0;
}

static void stm32_chip_suspend(struct stm32_exti_chip_data *chip_data,
                               u32 wake_active)
{
        const struct stm32_exti_bank *stm32_bank = chip_data->reg_bank;
        void __iomem *base = chip_data->host_data->base;

        /* save rtsr, ftsr registers */
        chip_data->rtsr_cache = readl_relaxed(base + stm32_bank->rtsr_ofst);
        chip_data->ftsr_cache = readl_relaxed(base + stm32_bank->ftsr_ofst);

        writel_relaxed(wake_active, base + stm32_bank->imr_ofst);
}

static void stm32_chip_resume(struct stm32_exti_chip_data *chip_data,
                              u32 mask_cache)
{
        const struct stm32_exti_bank *stm32_bank = chip_data->reg_bank;
        void __iomem *base = chip_data->host_data->base;

        /* restore rtsr, ftsr, registers */
        writel_relaxed(chip_data->rtsr_cache, base + stm32_bank->rtsr_ofst);
        writel_relaxed(chip_data->ftsr_cache, base + stm32_bank->ftsr_ofst);

        writel_relaxed(mask_cache, base + stm32_bank->imr_ofst);
}

static void stm32_irq_suspend(struct irq_chip_generic *gc)
{
        struct stm32_exti_chip_data *chip_data = gc->private;

        guard(raw_spinlock)(&gc->lock);
        stm32_chip_suspend(chip_data, gc->wake_active);
}

static void stm32_irq_resume(struct irq_chip_generic *gc)
{
        struct stm32_exti_chip_data *chip_data = gc->private;

        guard(raw_spinlock)(&gc->lock);
        stm32_chip_resume(chip_data, gc->mask_cache);
}

static int stm32_exti_alloc(struct irq_domain *d, unsigned int virq,
                            unsigned int nr_irqs, void *data)
{
        struct irq_fwspec *fwspec = data;
        irq_hw_number_t hwirq;

        hwirq = fwspec->param[0];

        irq_map_generic_chip(d, virq, hwirq);

        return 0;
}

static void stm32_exti_free(struct irq_domain *d, unsigned int virq,
                            unsigned int nr_irqs)
{
        struct irq_data *data = irq_domain_get_irq_data(d, virq);

        irq_domain_reset_irq_data(data);
}

static const struct irq_domain_ops irq_exti_domain_ops = {
        .map    = irq_map_generic_chip,
        .alloc  = stm32_exti_alloc,
        .free   = stm32_exti_free,
        .xlate  = irq_domain_xlate_twocell,
};

static void stm32_irq_ack(struct irq_data *d)
{
        struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
        struct stm32_exti_chip_data *chip_data = gc->private;
        const struct stm32_exti_bank *stm32_bank = chip_data->reg_bank;

        guard(raw_spinlock)(&gc->lock);
        irq_reg_writel(gc, d->mask, stm32_bank->rpr_ofst);
}

static struct
stm32_exti_host_data *stm32_exti_host_init(const struct stm32_exti_drv_data *dd,
                                           struct device_node *node)
{
        struct stm32_exti_host_data *host_data;

        host_data = kzalloc_obj(*host_data);
        if (!host_data)
                return NULL;

        host_data->drv_data = dd;
        host_data->chips_data = kzalloc_objs(struct stm32_exti_chip_data,
                                             dd->bank_nr);
        if (!host_data->chips_data)
                goto free_host_data;

        host_data->base = of_iomap(node, 0);
        if (!host_data->base) {
                pr_err("%pOF: Unable to map registers\n", node);
                goto free_chips_data;
        }

        return host_data;

free_chips_data:
        kfree(host_data->chips_data);
free_host_data:
        kfree(host_data);

        return NULL;
}

static struct
stm32_exti_chip_data *stm32_exti_chip_init(struct stm32_exti_host_data *h_data,
                                           u32 bank_idx,
                                           struct device_node *node)
{
        const struct stm32_exti_bank *stm32_bank;
        struct stm32_exti_chip_data *chip_data;
        void __iomem *base = h_data->base;

        stm32_bank = h_data->drv_data->exti_banks[bank_idx];
        chip_data = &h_data->chips_data[bank_idx];
        chip_data->host_data = h_data;
        chip_data->reg_bank = stm32_bank;

        /*
         * This IP has no reset, so after hot reboot we should
         * clear registers to avoid residue
         */
        writel_relaxed(0, base + stm32_bank->imr_ofst);
        writel_relaxed(0, base + stm32_bank->emr_ofst);

        pr_info("%pOF: bank%d\n", node, bank_idx);

        return chip_data;
}

static int __init stm32_exti_init(const struct stm32_exti_drv_data *drv_data,
                                  struct device_node *node)
{
        struct stm32_exti_host_data *host_data;
        unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
        int nr_irqs, ret, i;
        struct irq_chip_generic *gc;
        struct irq_domain *domain;

        host_data = stm32_exti_host_init(drv_data, node);
        if (!host_data)
                return -ENOMEM;

        domain = irq_domain_create_linear(of_fwnode_handle(node), drv_data->bank_nr * IRQS_PER_BANK,
                                          &irq_exti_domain_ops, NULL);
        if (!domain) {
                pr_err("%pOFn: Could not register interrupt domain.\n",
                       node);
                ret = -ENOMEM;
                goto out_unmap;
        }

        ret = irq_alloc_domain_generic_chips(domain, IRQS_PER_BANK, 1, "exti",
                                             handle_edge_irq, clr, 0, 0);
        if (ret) {
                pr_err("%pOF: Could not allocate generic interrupt chip.\n",
                       node);
                goto out_free_domain;
        }

        for (i = 0; i < drv_data->bank_nr; i++) {
                const struct stm32_exti_bank *stm32_bank;
                struct stm32_exti_chip_data *chip_data;

                stm32_bank = drv_data->exti_banks[i];
                chip_data = stm32_exti_chip_init(host_data, i, node);

                gc = irq_get_domain_generic_chip(domain, i * IRQS_PER_BANK);

                gc->reg_base = host_data->base;
                gc->chip_types->type = IRQ_TYPE_EDGE_BOTH;
                gc->chip_types->chip.irq_ack = stm32_irq_ack;
                gc->chip_types->chip.irq_mask = irq_gc_mask_clr_bit;
                gc->chip_types->chip.irq_unmask = irq_gc_mask_set_bit;
                gc->chip_types->chip.irq_set_type = stm32_irq_set_type;
                gc->chip_types->chip.irq_set_wake = irq_gc_set_wake;
                gc->suspend = stm32_irq_suspend;
                gc->resume = stm32_irq_resume;
                gc->wake_enabled = IRQ_MSK(IRQS_PER_BANK);

                gc->chip_types->regs.mask = stm32_bank->imr_ofst;
                gc->private = (void *)chip_data;
        }

        nr_irqs = of_irq_count(node);
        for (i = 0; i < nr_irqs; i++) {
                unsigned int irq = irq_of_parse_and_map(node, i);

                irq_set_handler_data(irq, domain);
                irq_set_chained_handler(irq, stm32_irq_handler);
        }

        return 0;

out_free_domain:
        irq_domain_remove(domain);
out_unmap:
        iounmap(host_data->base);
        kfree(host_data->chips_data);
        kfree(host_data);
        return ret;
}

static int __init stm32f4_exti_of_init(struct device_node *np,
                                       struct device_node *parent)
{
        return stm32_exti_init(&stm32f4xx_drv_data, np);
}

IRQCHIP_DECLARE(stm32f4_exti, "st,stm32-exti", stm32f4_exti_of_init);

static int __init stm32h7_exti_of_init(struct device_node *np,
                                       struct device_node *parent)
{
        return stm32_exti_init(&stm32h7xx_drv_data, np);
}

IRQCHIP_DECLARE(stm32h7_exti, "st,stm32h7-exti", stm32h7_exti_of_init);