// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2015, Linaro Limited, Shannon Zhao
 */

#include <linux/platform_device.h>
#include <linux/acpi.h>
#include <xen/xen.h>
#include <xen/page.h>
#include <xen/interface/memory.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>

static int xen_unmap_device_mmio(const struct resource *resources,
                                 unsigned int count)
{
        unsigned int i, j, nr;
        int rc = 0;
        const struct resource *r;
        struct xen_remove_from_physmap xrp;

        for (i = 0; i < count; i++) {
                r = &resources[i];
                nr = DIV_ROUND_UP(resource_size(r), XEN_PAGE_SIZE);
                if ((resource_type(r) != IORESOURCE_MEM) || (nr == 0))
                        continue;

                for (j = 0; j < nr; j++) {
                        xrp.domid = DOMID_SELF;
                        xrp.gpfn = XEN_PFN_DOWN(r->start) + j;
                        rc = HYPERVISOR_memory_op(XENMEM_remove_from_physmap,
                                                  &xrp);
                        if (rc)
                                return rc;
                }
        }

        return rc;
}

static int xen_map_device_mmio(const struct resource *resources,
                               unsigned int count)
{
        unsigned int i, j, nr;
        int rc = 0;
        const struct resource *r;
        xen_pfn_t *gpfns;
        xen_ulong_t *idxs;
        int *errs;

        for (i = 0; i < count; i++) {
                struct xen_add_to_physmap_range xatp = {
                        .domid = DOMID_SELF,
                        .space = XENMAPSPACE_dev_mmio
                };

                r = &resources[i];
                nr = DIV_ROUND_UP(resource_size(r), XEN_PAGE_SIZE);
                if ((resource_type(r) != IORESOURCE_MEM) || (nr == 0))
                        continue;

                gpfns = kzalloc_objs(xen_pfn_t, nr);
                idxs = kzalloc_objs(xen_ulong_t, nr);
                errs = kzalloc_objs(int, nr);
                if (!gpfns || !idxs || !errs) {
                        kfree(gpfns);
                        kfree(idxs);
                        kfree(errs);
                        rc = -ENOMEM;
                        goto unmap;
                }

                for (j = 0; j < nr; j++) {
                        /*
                         * The regions are always mapped 1:1 to DOM0 and this is
                         * fine because the memory map for DOM0 is the same as
                         * the host (except for the RAM).
                         */
                        gpfns[j] = XEN_PFN_DOWN(r->start) + j;
                        idxs[j] = XEN_PFN_DOWN(r->start) + j;
                }

                xatp.size = nr;

                set_xen_guest_handle(xatp.gpfns, gpfns);
                set_xen_guest_handle(xatp.idxs, idxs);
                set_xen_guest_handle(xatp.errs, errs);

                rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
                kfree(gpfns);
                kfree(idxs);
                kfree(errs);
                if (rc)
                        goto unmap;
        }

        return rc;

unmap:
        xen_unmap_device_mmio(resources, i);
        return rc;
}

static int xen_platform_notifier(struct notifier_block *nb,
                                 unsigned long action, void *data)
{
        struct platform_device *pdev = to_platform_device(data);
        int r = 0;

        if (pdev->num_resources == 0 || pdev->resource == NULL)
                return NOTIFY_OK;

        switch (action) {
        case BUS_NOTIFY_ADD_DEVICE:
                r = xen_map_device_mmio(pdev->resource, pdev->num_resources);
                break;
        case BUS_NOTIFY_DEL_DEVICE:
                r = xen_unmap_device_mmio(pdev->resource, pdev->num_resources);
                break;
        default:
                return NOTIFY_DONE;
        }
        if (r)
                dev_err(&pdev->dev, "Platform: Failed to %s device %s MMIO!\n",
                        action == BUS_NOTIFY_ADD_DEVICE ? "map" :
                        (action == BUS_NOTIFY_DEL_DEVICE ? "unmap" : "?"),
                        pdev->name);

        return NOTIFY_OK;
}

static struct notifier_block platform_device_nb = {
        .notifier_call = xen_platform_notifier,
};

static int __init register_xen_platform_notifier(void)
{
        if (!xen_initial_domain() || acpi_disabled)
                return 0;

        return bus_register_notifier(&platform_bus_type, &platform_device_nb);
}

arch_initcall(register_xen_platform_notifier);

#ifdef CONFIG_ARM_AMBA
#include <linux/amba/bus.h>

static int xen_amba_notifier(struct notifier_block *nb,
                             unsigned long action, void *data)
{
        struct amba_device *adev = to_amba_device(data);
        int r = 0;

        switch (action) {
        case BUS_NOTIFY_ADD_DEVICE:
                r = xen_map_device_mmio(&adev->res, 1);
                break;
        case BUS_NOTIFY_DEL_DEVICE:
                r = xen_unmap_device_mmio(&adev->res, 1);
                break;
        default:
                return NOTIFY_DONE;
        }
        if (r)
                dev_err(&adev->dev, "AMBA: Failed to %s device %s MMIO!\n",
                        action == BUS_NOTIFY_ADD_DEVICE ? "map" :
                        (action == BUS_NOTIFY_DEL_DEVICE ? "unmap" : "?"),
                        adev->dev.init_name);

        return NOTIFY_OK;
}

static struct notifier_block amba_device_nb = {
        .notifier_call = xen_amba_notifier,
};

static int __init register_xen_amba_notifier(void)
{
        if (!xen_initial_domain() || acpi_disabled)
                return 0;

        return bus_register_notifier(&amba_bustype, &amba_device_nb);
}

arch_initcall(register_xen_amba_notifier);
#endif