#include "qemu/osdep.h"
#include "qemu/units.h"
#include "qemu/error-report.h"
#include "hw/mem/memory-device.h"
#include "hw/mem/pc-dimm.h"
#include "hw/pci/pci.h"
#include "hw/qdev-properties.h"
#include "qapi/error.h"
#include "qemu/log.h"
#include "qemu/module.h"
#include "qemu/pmem.h"
#include "qemu/range.h"
#include "qemu/rcu.h"
#include "sysemu/hostmem.h"
#include "hw/cxl/cxl.h"

static void build_dvsecs(CXLType3Dev *ct3d)
{
    CXLComponentState *cxl_cstate = &ct3d->cxl_cstate;
    uint8_t *dvsec;

    dvsec = (uint8_t *)&(CXLDVSECDevice){
        .cap = 0x1e,
        .ctrl = 0x2,
        .status2 = 0x2,
        .range1_size_hi = ct3d->hostmem->size >> 32,
        .range1_size_lo = (2 << 5) | (2 << 2) | 0x3 |
        (ct3d->hostmem->size & 0xF0000000),
        .range1_base_hi = 0,
        .range1_base_lo = 0,
    };
    cxl_component_create_dvsec(cxl_cstate, CXL2_TYPE3_DEVICE,
                               PCIE_CXL_DEVICE_DVSEC_LENGTH,
                               PCIE_CXL_DEVICE_DVSEC,
                               PCIE_CXL2_DEVICE_DVSEC_REVID, dvsec);

    dvsec = (uint8_t *)&(CXLDVSECRegisterLocator){
        .rsvd         = 0,
        .reg0_base_lo = RBI_COMPONENT_REG | CXL_COMPONENT_REG_BAR_IDX,
        .reg0_base_hi = 0,
        .reg1_base_lo = RBI_CXL_DEVICE_REG | CXL_DEVICE_REG_BAR_IDX,
        .reg1_base_hi = 0,
    };
    cxl_component_create_dvsec(cxl_cstate, CXL2_TYPE3_DEVICE,
                               REG_LOC_DVSEC_LENGTH, REG_LOC_DVSEC,
                               REG_LOC_DVSEC_REVID, dvsec);
    dvsec = (uint8_t *)&(CXLDVSECDeviceGPF){
        .phase2_duration = 0x603, /* 3 seconds */
        .phase2_power = 0x33, /* 0x33 miliwatts */
    };
    cxl_component_create_dvsec(cxl_cstate, CXL2_TYPE3_DEVICE,
                               GPF_DEVICE_DVSEC_LENGTH, GPF_PORT_DVSEC,
                               GPF_DEVICE_DVSEC_REVID, dvsec);
}

static void hdm_decoder_commit(CXLType3Dev *ct3d, int which)
{
    ComponentRegisters *cregs = &ct3d->cxl_cstate.crb;
    uint32_t *cache_mem = cregs->cache_mem_registers;

    assert(which == 0);

    /* TODO: Sanity checks that the decoder is possible */
    ARRAY_FIELD_DP32(cache_mem, CXL_HDM_DECODER0_CTRL, COMMIT, 0);
    ARRAY_FIELD_DP32(cache_mem, CXL_HDM_DECODER0_CTRL, ERR, 0);

    ARRAY_FIELD_DP32(cache_mem, CXL_HDM_DECODER0_CTRL, COMMITTED, 1);
}

static void ct3d_reg_write(void *opaque, hwaddr offset, uint64_t value,
                           unsigned size)
{
    CXLComponentState *cxl_cstate = opaque;
    ComponentRegisters *cregs = &cxl_cstate->crb;
    CXLType3Dev *ct3d = container_of(cxl_cstate, CXLType3Dev, cxl_cstate);
    uint32_t *cache_mem = cregs->cache_mem_registers;
    bool should_commit = false;
    int which_hdm = -1;

    assert(size == 4);
    g_assert(offset < CXL2_COMPONENT_CM_REGION_SIZE);

    switch (offset) {
    case A_CXL_HDM_DECODER0_CTRL:
        should_commit = FIELD_EX32(value, CXL_HDM_DECODER0_CTRL, COMMIT);
        which_hdm = 0;
        break;
    default:
        break;
    }

    stl_le_p((uint8_t *)cache_mem + offset, value);
    if (should_commit) {
        hdm_decoder_commit(ct3d, which_hdm);
    }
}

static bool cxl_setup_memory(CXLType3Dev *ct3d, Error **errp)
{
    DeviceState *ds = DEVICE(ct3d);
    MemoryRegion *mr;
    char *name;

    if (!ct3d->hostmem) {
        error_setg(errp, "memdev property must be set");
        return false;
    }

    mr = host_memory_backend_get_memory(ct3d->hostmem);
    if (!mr) {
        error_setg(errp, "memdev property must be set");
        return false;
    }
    memory_region_set_nonvolatile(mr, true);
    memory_region_set_enabled(mr, true);
    host_memory_backend_set_mapped(ct3d->hostmem, true);

    if (ds->id) {
        name = g_strdup_printf("cxl-type3-dpa-space:%s", ds->id);
    } else {
        name = g_strdup("cxl-type3-dpa-space");
    }
    address_space_init(&ct3d->hostmem_as, mr, name);
    g_free(name);

    ct3d->cxl_dstate.pmem_size = ct3d->hostmem->size;

    if (!ct3d->lsa) {
        error_setg(errp, "lsa property must be set");
        return false;
    }

    return true;
}

static void ct3_realize(PCIDevice *pci_dev, Error **errp)
{
    CXLType3Dev *ct3d = CXL_TYPE3(pci_dev);
    CXLComponentState *cxl_cstate = &ct3d->cxl_cstate;
    ComponentRegisters *regs = &cxl_cstate->crb;
    MemoryRegion *mr = &regs->component_registers;
    uint8_t *pci_conf = pci_dev->config;

    if (!cxl_setup_memory(ct3d, errp)) {
        return;
    }

    pci_config_set_prog_interface(pci_conf, 0x10);
    pci_config_set_class(pci_conf, PCI_CLASS_MEMORY_CXL);

    pcie_endpoint_cap_init(pci_dev, 0x80);
    cxl_cstate->dvsec_offset = 0x100;

    ct3d->cxl_cstate.pdev = pci_dev;
    build_dvsecs(ct3d);

    regs->special_ops = g_new0(MemoryRegionOps, 1);
    regs->special_ops->write = ct3d_reg_write;

    cxl_component_register_block_init(OBJECT(pci_dev), cxl_cstate,
                                      TYPE_CXL_TYPE3);

    pci_register_bar(
        pci_dev, CXL_COMPONENT_REG_BAR_IDX,
        PCI_BASE_ADDRESS_SPACE_MEMORY | PCI_BASE_ADDRESS_MEM_TYPE_64, mr);

    cxl_device_register_block_init(OBJECT(pci_dev), &ct3d->cxl_dstate);
    pci_register_bar(pci_dev, CXL_DEVICE_REG_BAR_IDX,
                     PCI_BASE_ADDRESS_SPACE_MEMORY |
                         PCI_BASE_ADDRESS_MEM_TYPE_64,
                     &ct3d->cxl_dstate.device_registers);
}

static void ct3_exit(PCIDevice *pci_dev)
{
    CXLType3Dev *ct3d = CXL_TYPE3(pci_dev);
    CXLComponentState *cxl_cstate = &ct3d->cxl_cstate;
    ComponentRegisters *regs = &cxl_cstate->crb;

    g_free(regs->special_ops);
    address_space_destroy(&ct3d->hostmem_as);
}

/* TODO: Support multiple HDM decoders and DPA skip */
static bool cxl_type3_dpa(CXLType3Dev *ct3d, hwaddr host_addr, uint64_t *dpa)
{
    uint32_t *cache_mem = ct3d->cxl_cstate.crb.cache_mem_registers;
    uint64_t decoder_base, decoder_size, hpa_offset;
    uint32_t hdm0_ctrl;
    int ig, iw;

    decoder_base = (((uint64_t)cache_mem[R_CXL_HDM_DECODER0_BASE_HI] << 32) |
                    cache_mem[R_CXL_HDM_DECODER0_BASE_LO]);
    if ((uint64_t)host_addr < decoder_base) {
        return false;
    }

    hpa_offset = (uint64_t)host_addr - decoder_base;

    decoder_size = ((uint64_t)cache_mem[R_CXL_HDM_DECODER0_SIZE_HI] << 32) |
        cache_mem[R_CXL_HDM_DECODER0_SIZE_LO];
    if (hpa_offset >= decoder_size) {
        return false;
    }

    hdm0_ctrl = cache_mem[R_CXL_HDM_DECODER0_CTRL];
    iw = FIELD_EX32(hdm0_ctrl, CXL_HDM_DECODER0_CTRL, IW);
    ig = FIELD_EX32(hdm0_ctrl, CXL_HDM_DECODER0_CTRL, IG);

    *dpa = (MAKE_64BIT_MASK(0, 8 + ig) & hpa_offset) |
        ((MAKE_64BIT_MASK(8 + ig + iw, 64 - 8 - ig - iw) & hpa_offset) >> iw);

    return true;
}

MemTxResult cxl_type3_read(PCIDevice *d, hwaddr host_addr, uint64_t *data,
                           unsigned size, MemTxAttrs attrs)
{
    CXLType3Dev *ct3d = CXL_TYPE3(d);
    uint64_t dpa_offset;
    MemoryRegion *mr;

    /* TODO support volatile region */
    mr = host_memory_backend_get_memory(ct3d->hostmem);
    if (!mr) {
        return MEMTX_ERROR;
    }

    if (!cxl_type3_dpa(ct3d, host_addr, &dpa_offset)) {
        return MEMTX_ERROR;
    }

    if (dpa_offset > int128_get64(mr->size)) {
        return MEMTX_ERROR;
    }

    return address_space_read(&ct3d->hostmem_as, dpa_offset, attrs, data, size);
}

MemTxResult cxl_type3_write(PCIDevice *d, hwaddr host_addr, uint64_t data,
                            unsigned size, MemTxAttrs attrs)
{
    CXLType3Dev *ct3d = CXL_TYPE3(d);
    uint64_t dpa_offset;
    MemoryRegion *mr;

    mr = host_memory_backend_get_memory(ct3d->hostmem);
    if (!mr) {
        return MEMTX_OK;
    }

    if (!cxl_type3_dpa(ct3d, host_addr, &dpa_offset)) {
        return MEMTX_OK;
    }

    if (dpa_offset > int128_get64(mr->size)) {
        return MEMTX_OK;
    }
    return address_space_write(&ct3d->hostmem_as, dpa_offset, attrs,
                               &data, size);
}

static void ct3d_reset(DeviceState *dev)
{
    CXLType3Dev *ct3d = CXL_TYPE3(dev);
    uint32_t *reg_state = ct3d->cxl_cstate.crb.cache_mem_registers;
    uint32_t *write_msk = ct3d->cxl_cstate.crb.cache_mem_regs_write_mask;

    cxl_component_register_init_common(reg_state, write_msk, CXL2_TYPE3_DEVICE);
    cxl_device_register_init_common(&ct3d->cxl_dstate);
}

static Property ct3_props[] = {
    DEFINE_PROP_LINK("memdev", CXLType3Dev, hostmem, TYPE_MEMORY_BACKEND,
                     HostMemoryBackend *),
    DEFINE_PROP_LINK("lsa", CXLType3Dev, lsa, TYPE_MEMORY_BACKEND,
                     HostMemoryBackend *),
    DEFINE_PROP_END_OF_LIST(),
};

static uint64_t get_lsa_size(CXLType3Dev *ct3d)
{
    MemoryRegion *mr;

    mr = host_memory_backend_get_memory(ct3d->lsa);
    return memory_region_size(mr);
}

static void validate_lsa_access(MemoryRegion *mr, uint64_t size,
                                uint64_t offset)
{
    assert(offset + size <= memory_region_size(mr));
    assert(offset + size > offset);
}

static uint64_t get_lsa(CXLType3Dev *ct3d, void *buf, uint64_t size,
                    uint64_t offset)
{
    MemoryRegion *mr;
    void *lsa;

    mr = host_memory_backend_get_memory(ct3d->lsa);
    validate_lsa_access(mr, size, offset);

    lsa = memory_region_get_ram_ptr(mr) + offset;
    memcpy(buf, lsa, size);

    return size;
}

static void set_lsa(CXLType3Dev *ct3d, const void *buf, uint64_t size,
                    uint64_t offset)
{
    MemoryRegion *mr;
    void *lsa;

    mr = host_memory_backend_get_memory(ct3d->lsa);
    validate_lsa_access(mr, size, offset);

    lsa = memory_region_get_ram_ptr(mr) + offset;
    memcpy(lsa, buf, size);
    memory_region_set_dirty(mr, offset, size);

    /*
     * Just like the PMEM, if the guest is not allowed to exit gracefully, label
     * updates will get lost.
     */
}

static void ct3_class_init(ObjectClass *oc, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(oc);
    PCIDeviceClass *pc = PCI_DEVICE_CLASS(oc);
    CXLType3Class *cvc = CXL_TYPE3_CLASS(oc);

    pc->realize = ct3_realize;
    pc->exit = ct3_exit;
    pc->class_id = PCI_CLASS_STORAGE_EXPRESS;
    pc->vendor_id = PCI_VENDOR_ID_INTEL;
    pc->device_id = 0xd93; /* LVF for now */
    pc->revision = 1;

    set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
    dc->desc = "CXL PMEM Device (Type 3)";
    dc->reset = ct3d_reset;
    device_class_set_props(dc, ct3_props);

    cvc->get_lsa_size = get_lsa_size;
    cvc->get_lsa = get_lsa;
    cvc->set_lsa = set_lsa;
}

static const TypeInfo ct3d_info = {
    .name = TYPE_CXL_TYPE3,
    .parent = TYPE_PCI_DEVICE,
    .class_size = sizeof(struct CXLType3Class),
    .class_init = ct3_class_init,
    .instance_size = sizeof(CXLType3Dev),
    .interfaces = (InterfaceInfo[]) {
        { INTERFACE_CXL_DEVICE },
        { INTERFACE_PCIE_DEVICE },
        {}
    },
};

static void ct3d_registers(void)
{
    type_register_static(&ct3d_info);
}

type_init(ct3d_registers);