root/drivers/irqchip/irq-bcm2712-mip.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2024 Raspberry Pi Ltd., All Rights Reserved.
 * Copyright (c) 2024 SUSE
 */

#include <linux/bitmap.h>
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
#include <linux/msi.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>

#include <linux/irqchip/irq-msi-lib.h>

#define MIP_INT_RAISE           0x00
#define MIP_INT_CLEAR           0x10
#define MIP_INT_CFGL_HOST       0x20
#define MIP_INT_CFGH_HOST       0x30
#define MIP_INT_MASKL_HOST      0x40
#define MIP_INT_MASKH_HOST      0x50
#define MIP_INT_MASKL_VPU       0x60
#define MIP_INT_MASKH_VPU       0x70
#define MIP_INT_STATUSL_HOST    0x80
#define MIP_INT_STATUSH_HOST    0x90
#define MIP_INT_STATUSL_VPU     0xa0
#define MIP_INT_STATUSH_VPU     0xb0

/**
 * struct mip_priv - MSI-X interrupt controller data
 * @lock:       Used to protect bitmap alloc/free
 * @base:       Base address of MMIO area
 * @msg_addr:   PCIe MSI-X address
 * @msi_base:   MSI base
 * @num_msis:   Count of MSIs
 * @msi_offset: MSI offset
 * @bitmap:     A bitmap for hwirqs
 * @parent:     Parent domain (GIC)
 * @dev:        A device pointer
 */
struct mip_priv {
        spinlock_t              lock;
        void __iomem            *base;
        u64                     msg_addr;
        u32                     msi_base;
        u32                     num_msis;
        u32                     msi_offset;
        unsigned long           *bitmap;
        struct irq_domain       *parent;
        struct device           *dev;
};

static void mip_compose_msi_msg(struct irq_data *d, struct msi_msg *msg)
{
        struct mip_priv *mip = irq_data_get_irq_chip_data(d);

        msg->address_hi = upper_32_bits(mip->msg_addr);
        msg->address_lo = lower_32_bits(mip->msg_addr);
        msg->data = d->hwirq;
}

static struct irq_chip mip_middle_irq_chip = {
        .name                   = "MIP",
        .irq_mask               = irq_chip_mask_parent,
        .irq_unmask             = irq_chip_unmask_parent,
        .irq_eoi                = irq_chip_eoi_parent,
        .irq_set_affinity       = irq_chip_set_affinity_parent,
        .irq_set_type           = irq_chip_set_type_parent,
        .irq_compose_msi_msg    = mip_compose_msi_msg,
};

static int mip_alloc_hwirq(struct mip_priv *mip, unsigned int nr_irqs)
{
        guard(spinlock)(&mip->lock);
        return bitmap_find_free_region(mip->bitmap, mip->num_msis, ilog2(nr_irqs));
}

static void mip_free_hwirq(struct mip_priv *mip, unsigned int hwirq,
                           unsigned int nr_irqs)
{
        guard(spinlock)(&mip->lock);
        bitmap_release_region(mip->bitmap, hwirq, ilog2(nr_irqs));
}

static int mip_middle_domain_alloc(struct irq_domain *domain, unsigned int virq,
                                   unsigned int nr_irqs, void *arg)
{
        struct mip_priv *mip = domain->host_data;
        struct irq_fwspec fwspec = {0};
        unsigned int hwirq, i;
        struct irq_data *irqd;
        int irq, ret;

        irq = mip_alloc_hwirq(mip, nr_irqs);
        if (irq < 0)
                return irq;

        hwirq = irq + mip->msi_offset;

        fwspec.fwnode = domain->parent->fwnode;
        fwspec.param_count = 3;
        fwspec.param[0] = 0;
        fwspec.param[1] = hwirq + mip->msi_base;
        fwspec.param[2] = IRQ_TYPE_EDGE_RISING;

        ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &fwspec);
        if (ret)
                goto err_free_hwirq;

        for (i = 0; i < nr_irqs; i++) {
                irqd = irq_domain_get_irq_data(domain->parent, virq + i);
                irqd->chip->irq_set_type(irqd, IRQ_TYPE_EDGE_RISING);

                ret = irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
                                                    &mip_middle_irq_chip, mip);
                if (ret)
                        goto err_free;

                irqd = irq_get_irq_data(virq + i);
                irqd_set_single_target(irqd);
                irqd_set_affinity_on_activate(irqd);
        }

        return 0;

err_free:
        irq_domain_free_irqs_parent(domain, virq, nr_irqs);
err_free_hwirq:
        mip_free_hwirq(mip, irq, nr_irqs);
        return ret;
}

static void mip_middle_domain_free(struct irq_domain *domain, unsigned int virq,
                                   unsigned int nr_irqs)
{
        struct irq_data *irqd = irq_domain_get_irq_data(domain, virq);
        struct mip_priv *mip;
        unsigned int hwirq;

        if (!irqd)
                return;

        mip = irq_data_get_irq_chip_data(irqd);
        hwirq = irqd_to_hwirq(irqd);
        irq_domain_free_irqs_parent(domain, virq, nr_irqs);
        mip_free_hwirq(mip, hwirq - mip->msi_offset, nr_irqs);
}

static const struct irq_domain_ops mip_middle_domain_ops = {
        .select         = msi_lib_irq_domain_select,
        .alloc          = mip_middle_domain_alloc,
        .free           = mip_middle_domain_free,
};

#define MIP_MSI_FLAGS_REQUIRED  (MSI_FLAG_USE_DEF_DOM_OPS |     \
                                 MSI_FLAG_USE_DEF_CHIP_OPS |    \
                                 MSI_FLAG_PCI_MSI_MASK_PARENT)

#define MIP_MSI_FLAGS_SUPPORTED (MSI_GENERIC_FLAGS_MASK |       \
                                 MSI_FLAG_MULTI_PCI_MSI |       \
                                 MSI_FLAG_PCI_MSIX)

static const struct msi_parent_ops mip_msi_parent_ops = {
        .supported_flags        = MIP_MSI_FLAGS_SUPPORTED,
        .required_flags         = MIP_MSI_FLAGS_REQUIRED,
        .chip_flags             = MSI_CHIP_FLAG_SET_EOI | MSI_CHIP_FLAG_SET_ACK,
        .bus_select_token       = DOMAIN_BUS_GENERIC_MSI,
        .bus_select_mask        = MATCH_PCI_MSI,
        .prefix                 = "MIP-MSI-",
        .init_dev_msi_info      = msi_lib_init_dev_msi_info,
};

static int mip_init_domains(struct mip_priv *mip, struct device_node *np)
{
        struct irq_domain_info info = {
                .fwnode         = of_fwnode_handle(np),
                .ops            = &mip_middle_domain_ops,
                .host_data      = mip,
                .size           = mip->num_msis,
                .parent         = mip->parent,
                .dev            = mip->dev,
        };

        if (!msi_create_parent_irq_domain(&info, &mip_msi_parent_ops))
                return -ENOMEM;

        /*
         * All MSI-X unmasked for the host, masked for the VPU, and edge-triggered.
         */
        writel(0, mip->base + MIP_INT_MASKL_HOST);
        writel(0, mip->base + MIP_INT_MASKH_HOST);
        writel(~0, mip->base + MIP_INT_MASKL_VPU);
        writel(~0, mip->base + MIP_INT_MASKH_VPU);
        writel(~0, mip->base + MIP_INT_CFGL_HOST);
        writel(~0, mip->base + MIP_INT_CFGH_HOST);

        return 0;
}

static int mip_parse_dt(struct mip_priv *mip, struct device_node *np)
{
        struct of_phandle_args args;
        u64 size;
        int ret;

        ret = of_property_read_u32(np, "brcm,msi-offset", &mip->msi_offset);
        if (ret)
                mip->msi_offset = 0;

        ret = of_parse_phandle_with_args(np, "msi-ranges", "#interrupt-cells",
                                         0, &args);
        if (ret)
                return ret;

        ret = of_property_read_u32_index(np, "msi-ranges", args.args_count + 1,
                                         &mip->num_msis);
        if (ret)
                goto err_put;

        ret = of_property_read_reg(np, 1, &mip->msg_addr, &size);
        if (ret)
                goto err_put;

        mip->msi_base = args.args[1];

        mip->parent = irq_find_host(args.np);
        if (!mip->parent)
                ret = -EINVAL;

err_put:
        of_node_put(args.np);
        return ret;
}

static int mip_msi_probe(struct platform_device *pdev, struct device_node *parent)
{
        struct device_node *node = pdev->dev.of_node;
        struct mip_priv *mip;
        int ret;

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

        spin_lock_init(&mip->lock);
        mip->dev = &pdev->dev;

        ret = mip_parse_dt(mip, node);
        if (ret)
                goto err_priv;

        mip->base = of_iomap(node, 0);
        if (!mip->base) {
                ret = -ENXIO;
                goto err_priv;
        }

        mip->bitmap = bitmap_zalloc(mip->num_msis, GFP_KERNEL);
        if (!mip->bitmap) {
                ret = -ENOMEM;
                goto err_base;
        }

        ret = mip_init_domains(mip, node);
        if (ret)
                goto err_map;

        dev_dbg(&pdev->dev, "MIP: MSI-X count: %u, base: %u, offset: %u, msg_addr: %llx\n",
                mip->num_msis, mip->msi_base, mip->msi_offset, mip->msg_addr);

        return 0;

err_map:
        bitmap_free(mip->bitmap);
err_base:
        iounmap(mip->base);
err_priv:
        kfree(mip);
        return ret;
}

IRQCHIP_PLATFORM_DRIVER_BEGIN(mip_msi)
IRQCHIP_MATCH("brcm,bcm2712-mip", mip_msi_probe)
IRQCHIP_PLATFORM_DRIVER_END(mip_msi)
MODULE_DESCRIPTION("Broadcom BCM2712 MSI-X interrupt controller");
MODULE_AUTHOR("Phil Elwell <phil@raspberrypi.com>");
MODULE_AUTHOR("Stanimir Varbanov <svarbanov@suse.de>");
MODULE_LICENSE("GPL");