/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2019 Andrew Turner
 * Copyright (c) 2019 Ruslan Bukin <br@bsdpad.com>
 *
 * This software was developed by SRI International and the University of
 * Cambridge Computer Laboratory (Department of Computer Science and
 * Technology) under DARPA contract HR0011-18-C-0016 ("ECATS"), as part of the
 * DARPA SSITH research programme.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/bus.h>
#include <sys/endian.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/rman.h>

#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_page.h>
#include <vm/vm_phys.h>

#include <contrib/dev/acpica/include/acpi.h>
#include <contrib/dev/acpica/include/accommon.h>

#include <dev/acpica/acpivar.h>
#include <dev/acpica/acpi_pcibvar.h>

#include <dev/pci/pcivar.h>
#include <dev/pci/pcireg.h>
#include <dev/pci/pcib_private.h>
#include <dev/pci/pci_host_generic.h>
#include <dev/pci/pci_host_generic_acpi.h>

#include "pcib_if.h"

#define AP_NS_SHARED_MEM_BASE   0x06000000
#define N1SDP_MAX_SEGMENTS      2 /* Two PCIe root complex devices. */
#define BDF_TABLE_SIZE          (16 * 1024)
#define PCI_CFG_SPACE_SIZE      0x1000

_Static_assert(BDF_TABLE_SIZE >= PAGE_SIZE,
    "pci_n1sdp.c assumes a 4k or 16k page size when mapping the shared data");

struct pcie_discovery_data {
        uint32_t rc_base_addr;
        uint32_t nr_bdfs;
        uint32_t valid_bdfs[0];
};

struct generic_pcie_n1sdp_softc {
        struct generic_pcie_acpi_softc acpi;
        struct pcie_discovery_data *n1_discovery_data;
        bus_space_handle_t n1_bsh;
};

static int
n1sdp_init(struct generic_pcie_n1sdp_softc *sc)
{
        struct pcie_discovery_data *shared_data;
        void *vaddr;
        vm_paddr_t paddr_rc;
        vm_paddr_t paddr;
        vm_page_t m[BDF_TABLE_SIZE / PAGE_SIZE];
        int table_count;
        int bdfs_size;
        int error, i;

        paddr = AP_NS_SHARED_MEM_BASE + sc->acpi.segment * BDF_TABLE_SIZE;
        vm_phys_fictitious_reg_range(paddr, paddr + BDF_TABLE_SIZE,
            VM_MEMATTR_UNCACHEABLE);

        for (i = 0; i < nitems(m); i++) {
                m[i] = PHYS_TO_VM_PAGE(paddr + i * PAGE_SIZE);
                MPASS(m[i] != NULL);
        }

        vaddr = kva_alloc((vm_size_t)BDF_TABLE_SIZE);
        if (vaddr == NULL) {
                printf("%s: Can't allocate KVA memory.", __func__);
                error = ENXIO;
                goto out;
        }
        pmap_qenter(vaddr, m, nitems(m));

        shared_data = (struct pcie_discovery_data *)vaddr;
        paddr_rc = (vm_offset_t)shared_data->rc_base_addr;
        error = bus_space_map(sc->acpi.base.res->r_bustag, paddr_rc,
            PCI_CFG_SPACE_SIZE, 0, &sc->n1_bsh);
        if (error != 0)
                goto out_pmap;

        bdfs_size = sizeof(struct pcie_discovery_data) +
            sizeof(uint32_t) * shared_data->nr_bdfs;
        sc->n1_discovery_data = malloc(bdfs_size, M_DEVBUF,
            M_WAITOK | M_ZERO);
        memcpy(sc->n1_discovery_data, shared_data, bdfs_size);

        if (bootverbose) {
                table_count = sc->n1_discovery_data->nr_bdfs;
                for (i = 0; i < table_count; i++)
                        printf("valid bdf %x\n",
                            sc->n1_discovery_data->valid_bdfs[i]);
        }

out_pmap:
        pmap_qremove(vaddr, nitems(m));
        kva_free(vaddr, (vm_size_t)BDF_TABLE_SIZE);

out:
        vm_phys_fictitious_unreg_range(paddr, paddr + BDF_TABLE_SIZE);
        return (error);
}

static int
n1sdp_check_bdf(struct generic_pcie_n1sdp_softc *sc,
    u_int bus, u_int slot, u_int func)
{
        int table_count;
        int bdf;
        int i;

        bdf = PCIE_ADDR_OFFSET(bus, slot, func, 0);
        if (bdf == 0)
                return (1);

        table_count = sc->n1_discovery_data->nr_bdfs;

        for (i = 0; i < table_count; i++)
                if (bdf == sc->n1_discovery_data->valid_bdfs[i])
                        return (1);

        return (0);
}

static int
n1sdp_pcie_acpi_probe(device_t dev)
{
        ACPI_DEVICE_INFO *devinfo;
        ACPI_TABLE_HEADER *hdr;
        ACPI_STATUS status;
        ACPI_HANDLE h;
        int root;

        if (acpi_disabled("pcib") || (h = acpi_get_handle(dev)) == NULL ||
            ACPI_FAILURE(AcpiGetObjectInfo(h, &devinfo)))
                return (ENXIO);

        root = (devinfo->Flags & ACPI_PCI_ROOT_BRIDGE) != 0;
        AcpiOsFree(devinfo);
        if (!root)
                return (ENXIO);

        /* TODO: Move this to an ACPI quirk? */
        status = AcpiGetTable(ACPI_SIG_MCFG, 1, &hdr);
        if (ACPI_FAILURE(status))
                return (ENXIO);

        if (memcmp(hdr->OemId, "ARMLTD", ACPI_OEM_ID_SIZE) != 0 ||
            memcmp(hdr->OemTableId, "ARMN1SDP", ACPI_OEM_TABLE_ID_SIZE) != 0 ||
            hdr->OemRevision != 0x20181101)
                return (ENXIO);

        device_set_desc(dev, "ARM N1SDP PCI host controller");
        return (BUS_PROBE_DEFAULT);
}

static int
n1sdp_pcie_acpi_attach(device_t dev)
{
        struct generic_pcie_n1sdp_softc *sc;
        ACPI_HANDLE handle;
        ACPI_STATUS status;
        int err;

        err = pci_host_generic_acpi_init(dev);
        if (err != 0)
                return (err);

        sc = device_get_softc(dev);
        handle = acpi_get_handle(dev);

        /* Get PCI Segment (domain) needed for IOMMU space remap. */
        status = acpi_GetInteger(handle, "_SEG", &sc->acpi.segment);
        if (ACPI_FAILURE(status)) {
                device_printf(dev, "No _SEG for PCI Bus\n");
                return (ENXIO);
        }

        if (sc->acpi.segment >= N1SDP_MAX_SEGMENTS) {
                device_printf(dev, "Unknown PCI Bus segment (domain) %d\n",
                    sc->acpi.segment);
                return (ENXIO);
        }

        err = n1sdp_init(sc);
        if (err)
                return (err);

        device_add_child(dev, "pci", DEVICE_UNIT_ANY);
        bus_attach_children(dev);
        return (0);
}

static int
n1sdp_get_bus_space(device_t dev, u_int bus, u_int slot, u_int func, u_int reg,
    bus_space_tag_t *bst, bus_space_handle_t *bsh, bus_size_t *offset)
{
        struct generic_pcie_n1sdp_softc *sc;

        sc = device_get_softc(dev);

        if (n1sdp_check_bdf(sc, bus, slot, func) == 0)
                return (EINVAL);

        if (bus == sc->acpi.base.bus_start) {
                if (slot != 0 || func != 0)
                        return (EINVAL);
                *bsh = sc->n1_bsh;
        } else {
                *bsh = rman_get_bushandle(sc->acpi.base.res);
        }

        *bst = rman_get_bustag(sc->acpi.base.res);
        *offset = PCIE_ADDR_OFFSET(bus - sc->acpi.base.bus_start, slot, func,
            reg);

        return (0);
}

static uint32_t
n1sdp_pcie_read_config(device_t dev, u_int bus, u_int slot,
    u_int func, u_int reg, int bytes)
{
        struct generic_pcie_n1sdp_softc *sc_n1sdp;
        struct generic_pcie_acpi_softc *sc_acpi;
        struct generic_pcie_core_softc *sc;
        bus_space_handle_t h;
        bus_space_tag_t t;
        bus_size_t offset;
        uint32_t data;

        sc_n1sdp = device_get_softc(dev);
        sc_acpi = &sc_n1sdp->acpi;
        sc = &sc_acpi->base;

        if ((bus < sc->bus_start) || (bus > sc->bus_end))
                return (~0U);
        if ((slot > PCI_SLOTMAX) || (func > PCI_FUNCMAX) ||
            (reg > PCIE_REGMAX))
                return (~0U);

        if (n1sdp_get_bus_space(dev, bus, slot, func, reg, &t, &h, &offset) !=0)
                return (~0U);

        data = bus_space_read_4(t, h, offset & ~3);

        switch (bytes) {
        case 1:
                data >>= (offset & 3) * 8;
                data &= 0xff;
                break;
        case 2:
                data >>= (offset & 3) * 8;
                data = le16toh(data);
                break;
        case 4:
                data = le32toh(data);
                break;
        default:
                return (~0U);
        }

        return (data);
}

static void
n1sdp_pcie_write_config(device_t dev, u_int bus, u_int slot,
    u_int func, u_int reg, uint32_t val, int bytes)
{
        struct generic_pcie_n1sdp_softc *sc_n1sdp;
        struct generic_pcie_acpi_softc *sc_acpi;
        struct generic_pcie_core_softc *sc;
        bus_space_handle_t h;
        bus_space_tag_t t;
        bus_size_t offset;
        uint32_t data;

        sc_n1sdp = device_get_softc(dev);
        sc_acpi = &sc_n1sdp->acpi;
        sc = &sc_acpi->base;

        if ((bus < sc->bus_start) || (bus > sc->bus_end))
                return;
        if ((slot > PCI_SLOTMAX) || (func > PCI_FUNCMAX) ||
            (reg > PCIE_REGMAX))
                return;

        if (n1sdp_get_bus_space(dev, bus, slot, func, reg, &t, &h, &offset) !=0)
                return;

        data = bus_space_read_4(t, h, offset & ~3);

        switch (bytes) {
        case 1:
                data &= ~(0xff << ((offset & 3) * 8));
                data |= (val & 0xff) << ((offset & 3) * 8);
                break;
        case 2:
                data &= ~(0xffff << ((offset & 3) * 8));
                data |= (val & 0xffff) << ((offset & 3) * 8);
                break;
        case 4:
                data = val;
                break;
        default:
                return;
        }

        bus_space_write_4(t, h, offset & ~3, data);
}

static int
n1sdp_pcie_acpi_request_feature(device_t pcib __unused, device_t dev __unused,
    enum pci_feature feature __unused)
{
        /*
         * HotPlug isn't supported on the N1SDP as it causes an interrupt storm
         */
        return (EINVAL);
}


static device_method_t n1sdp_pcie_acpi_methods[] = {
        DEVMETHOD(device_probe,         n1sdp_pcie_acpi_probe),
        DEVMETHOD(device_attach,        n1sdp_pcie_acpi_attach),

        /* pcib interface */
        DEVMETHOD(pcib_read_config,     n1sdp_pcie_read_config),
        DEVMETHOD(pcib_write_config,    n1sdp_pcie_write_config),
        DEVMETHOD(pcib_request_feature, n1sdp_pcie_acpi_request_feature),

        DEVMETHOD_END
};

DEFINE_CLASS_1(pcib, n1sdp_pcie_acpi_driver, n1sdp_pcie_acpi_methods,
    sizeof(struct generic_pcie_n1sdp_softc), generic_pcie_acpi_driver);

DRIVER_MODULE(n1sdp_pcib, acpi, n1sdp_pcie_acpi_driver, 0, 0);