// SPDX-License-Identifier: GPL-2.0
/*
 * leon_pci.c: LEON Host PCI support
 *
 * Copyright (C) 2011 Aeroflex Gaisler AB, Daniel Hellstrom
 *
 * Code is partially derived from pcic.c
 */

#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/export.h>
#include <asm/leon.h>
#include <asm/leon_pci.h>

/* The LEON architecture does not rely on a BIOS or bootloader to setup
 * PCI for us. The Linux generic routines are used to setup resources,
 * reset values of configuration-space register settings are preserved.
 *
 * PCI Memory and Prefetchable Memory is direct-mapped. However I/O Space is
 * accessed through a Window which is translated to low 64KB in PCI space, the
 * first 4KB is not used so 60KB is available.
 */
void leon_pci_init(struct platform_device *ofdev, struct leon_pci_info *info)
{
        LIST_HEAD(resources);
        struct pci_bus *root_bus;
        struct pci_host_bridge *bridge;
        int ret;

        bridge = pci_alloc_host_bridge(0);
        if (!bridge)
                return;

        pci_add_resource_offset(&resources, &info->io_space,
                                info->io_space.start - 0x1000);
        pci_add_resource(&resources, &info->mem_space);
        info->busn.flags = IORESOURCE_BUS;
        pci_add_resource(&resources, &info->busn);

        list_splice_init(&resources, &bridge->windows);
        bridge->dev.parent = &ofdev->dev;
        bridge->sysdata = info;
        bridge->busnr = 0;
        bridge->ops = info->ops;
        bridge->swizzle_irq = pci_common_swizzle;
        bridge->map_irq = info->map_irq;

        ret = pci_scan_root_bus_bridge(bridge);
        if (ret) {
                pci_free_host_bridge(bridge);
                return;
        }

        root_bus = bridge->bus;

        /* Assign devices with resources */
        pci_assign_unassigned_resources();
        pci_bus_add_devices(root_bus);
}