/*
 * Kvaser PCI CAN device (SJA1000 based) emulation
 *
 * Copyright (c) 2013-2014 Jin Yang
 * Copyright (c) 2014-2018 Pavel Pisa
 *
 * Partially based on educational PCIexpress APOHW hardware
 * emulator used fro class A0B36APO at CTU FEE course by
 *    Rostislav Lisovy and Pavel Pisa
 *
 * Initial development supported by Google GSoC 2013 from RTEMS project slot
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "qemu/osdep.h"
#include "qemu/event_notifier.h"
#include "qemu/module.h"
#include "qemu/thread.h"
#include "qemu/sockets.h"
#include "qapi/error.h"
#include "chardev/char.h"
#include "hw/irq.h"
#include "hw/pci/pci_device.h"
#include "hw/qdev-properties.h"
#include "migration/vmstate.h"
#include "net/can_emu.h"

#include "can_sja1000.h"
#include "qom/object.h"

#define TYPE_CAN_PCI_DEV "kvaser_pci"

typedef struct KvaserPCIState KvaserPCIState;
DECLARE_INSTANCE_CHECKER(KvaserPCIState, KVASER_PCI_DEV,
                         TYPE_CAN_PCI_DEV)

#ifndef KVASER_PCI_VENDOR_ID1
#define KVASER_PCI_VENDOR_ID1     0x10e8    /* the PCI device and vendor IDs */
#endif

#ifndef KVASER_PCI_DEVICE_ID1
#define KVASER_PCI_DEVICE_ID1     0x8406
#endif

#define KVASER_PCI_S5920_RANGE    0x80
#define KVASER_PCI_SJA_RANGE      0x80
#define KVASER_PCI_XILINX_RANGE   0x8

#define KVASER_PCI_BYTES_PER_SJA  0x20

#define S5920_OMB                 0x0C
#define S5920_IMB                 0x1C
#define S5920_MBEF                0x34
#define S5920_INTCSR              0x38
#define S5920_RCR                 0x3C
#define S5920_PTCR                0x60

#define S5920_INTCSR_ADDON_INTENABLE_M        0x2000
#define S5920_INTCSR_INTERRUPT_ASSERTED_M     0x800000

#define KVASER_PCI_XILINX_VERINT  7   /* Lower nibble simulate interrupts,
                                         high nibble version number. */

#define KVASER_PCI_XILINX_VERSION_NUMBER 13

struct KvaserPCIState {
    /*< private >*/
    PCIDevice       dev;
    /*< public >*/
    MemoryRegion    s5920_io;
    MemoryRegion    sja_io;
    MemoryRegion    xilinx_io;

    CanSJA1000State sja_state;
    qemu_irq        irq;

    uint32_t        s5920_intcsr;
    uint32_t        s5920_irqstate;

    CanBusState     *canbus;
};

static void kvaser_pci_irq_handler(void *opaque, int irq_num, int level)
{
    KvaserPCIState *d = (KvaserPCIState *)opaque;

    d->s5920_irqstate = level;
    if (d->s5920_intcsr & S5920_INTCSR_ADDON_INTENABLE_M) {
        pci_set_irq(&d->dev, level);
    }
}

static void kvaser_pci_reset(DeviceState *dev)
{
    KvaserPCIState *d = KVASER_PCI_DEV(dev);
    CanSJA1000State *s = &d->sja_state;

    can_sja_hardware_reset(s);
}

static uint64_t kvaser_pci_s5920_io_read(void *opaque, hwaddr addr,
                                         unsigned size)
{
    KvaserPCIState *d = opaque;
    uint64_t val;

    switch (addr) {
    case S5920_INTCSR:
        val = d->s5920_intcsr;
        val &= ~S5920_INTCSR_INTERRUPT_ASSERTED_M;
        if (d->s5920_irqstate) {
            val |= S5920_INTCSR_INTERRUPT_ASSERTED_M;
        }
        return val;
    }
    return 0;
}

static void kvaser_pci_s5920_io_write(void *opaque, hwaddr addr, uint64_t data,
                                      unsigned size)
{
    KvaserPCIState *d = opaque;

    switch (addr) {
    case S5920_INTCSR:
        if (d->s5920_irqstate &&
            ((d->s5920_intcsr ^ data) & S5920_INTCSR_ADDON_INTENABLE_M)) {
            pci_set_irq(&d->dev, !!(data & S5920_INTCSR_ADDON_INTENABLE_M));
        }
        d->s5920_intcsr = data;
        break;
    }
}

static uint64_t kvaser_pci_sja_io_read(void *opaque, hwaddr addr, unsigned size)
{
    KvaserPCIState *d = opaque;
    CanSJA1000State *s = &d->sja_state;

    if (addr >= KVASER_PCI_BYTES_PER_SJA) {
        return 0;
    }

    return can_sja_mem_read(s, addr, size);
}

static void kvaser_pci_sja_io_write(void *opaque, hwaddr addr, uint64_t data,
                                    unsigned size)
{
    KvaserPCIState *d = opaque;
    CanSJA1000State *s = &d->sja_state;

    if (addr >= KVASER_PCI_BYTES_PER_SJA) {
        return;
    }

    can_sja_mem_write(s, addr, data, size);
}

static uint64_t kvaser_pci_xilinx_io_read(void *opaque, hwaddr addr,
                                          unsigned size)
{
    switch (addr) {
    case KVASER_PCI_XILINX_VERINT:
        return (KVASER_PCI_XILINX_VERSION_NUMBER << 4) | 0;
    }

    return 0;
}

static void kvaser_pci_xilinx_io_write(void *opaque, hwaddr addr, uint64_t data,
                             unsigned size)
{

}

static const MemoryRegionOps kvaser_pci_s5920_io_ops = {
    .read = kvaser_pci_s5920_io_read,
    .write = kvaser_pci_s5920_io_write,
    .endianness = DEVICE_LITTLE_ENDIAN,
    .impl = {
        .min_access_size = 4,
        .max_access_size = 4,
    },
};

static const MemoryRegionOps kvaser_pci_sja_io_ops = {
    .read = kvaser_pci_sja_io_read,
    .write = kvaser_pci_sja_io_write,
    .endianness = DEVICE_LITTLE_ENDIAN,
    .impl = {
        .max_access_size = 1,
    },
};

static const MemoryRegionOps kvaser_pci_xilinx_io_ops = {
    .read = kvaser_pci_xilinx_io_read,
    .write = kvaser_pci_xilinx_io_write,
    .endianness = DEVICE_LITTLE_ENDIAN,
    .impl = {
        .max_access_size = 1,
    },
};

static void kvaser_pci_realize(PCIDevice *pci_dev, Error **errp)
{
    KvaserPCIState *d = KVASER_PCI_DEV(pci_dev);
    CanSJA1000State *s = &d->sja_state;
    uint8_t *pci_conf;

    pci_conf = pci_dev->config;
    pci_conf[PCI_INTERRUPT_PIN] = 0x01; /* interrupt pin A */

    d->irq = qemu_allocate_irq(kvaser_pci_irq_handler, d, 0);

    can_sja_init(s, d->irq);

    if (can_sja_connect_to_bus(s, d->canbus) < 0) {
        error_setg(errp, "can_sja_connect_to_bus failed");
        return;
    }

    memory_region_init_io(&d->s5920_io, OBJECT(d), &kvaser_pci_s5920_io_ops,
                          d, "kvaser_pci-s5920", KVASER_PCI_S5920_RANGE);
    memory_region_init_io(&d->sja_io, OBJECT(d), &kvaser_pci_sja_io_ops,
                          d, "kvaser_pci-sja", KVASER_PCI_SJA_RANGE);
    memory_region_init_io(&d->xilinx_io, OBJECT(d), &kvaser_pci_xilinx_io_ops,
                          d, "kvaser_pci-xilinx", KVASER_PCI_XILINX_RANGE);

    pci_register_bar(&d->dev, /*BAR*/ 0, PCI_BASE_ADDRESS_SPACE_IO,
                                            &d->s5920_io);
    pci_register_bar(&d->dev, /*BAR*/ 1, PCI_BASE_ADDRESS_SPACE_IO,
                                            &d->sja_io);
    pci_register_bar(&d->dev, /*BAR*/ 2, PCI_BASE_ADDRESS_SPACE_IO,
                                            &d->xilinx_io);
}

static void kvaser_pci_exit(PCIDevice *pci_dev)
{
    KvaserPCIState *d = KVASER_PCI_DEV(pci_dev);
    CanSJA1000State *s = &d->sja_state;

    can_sja_disconnect(s);

    qemu_free_irq(d->irq);
}

static const VMStateDescription vmstate_kvaser_pci = {
    .name = "kvaser_pci",
    .version_id = 1,
    .minimum_version_id = 1,
    .fields = (const VMStateField[]) {
        VMSTATE_PCI_DEVICE(dev, KvaserPCIState),
        /* Load this before sja_state.  */
        VMSTATE_UINT32(s5920_intcsr, KvaserPCIState),
        VMSTATE_STRUCT(sja_state, KvaserPCIState, 0, vmstate_can_sja,
                       CanSJA1000State),
        VMSTATE_END_OF_LIST()
    }
};

static void kvaser_pci_instance_init(Object *obj)
{
    KvaserPCIState *d = KVASER_PCI_DEV(obj);

    object_property_add_link(obj, "canbus", TYPE_CAN_BUS,
                             (Object **)&d->canbus,
                             qdev_prop_allow_set_link_before_realize,
                             0);
}

static void kvaser_pci_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);
    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);

    k->realize = kvaser_pci_realize;
    k->exit = kvaser_pci_exit;
    k->vendor_id = KVASER_PCI_VENDOR_ID1;
    k->device_id = KVASER_PCI_DEVICE_ID1;
    k->revision = 0x00;
    k->class_id = 0x00ff00;
    dc->desc = "Kvaser PCICANx";
    dc->vmsd = &vmstate_kvaser_pci;
    device_class_set_legacy_reset(dc, kvaser_pci_reset);
    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
}

static const TypeInfo kvaser_pci_info = {
    .name          = TYPE_CAN_PCI_DEV,
    .parent        = TYPE_PCI_DEVICE,
    .instance_size = sizeof(KvaserPCIState),
    .class_init    = kvaser_pci_class_init,
    .instance_init = kvaser_pci_instance_init,
    .interfaces = (InterfaceInfo[]) {
        { INTERFACE_CONVENTIONAL_PCI_DEVICE },
        { },
    },
};

static void kvaser_pci_register_types(void)
{
    type_register_static(&kvaser_pci_info);
}

type_init(kvaser_pci_register_types)