/*
 * libqos driver framework
 *
 * Copyright (c) 2018 Emanuele Giuseppe Esposito <e.emanuelegiuseppe@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License version 2 as published by the Free Software Foundation.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>
 */

#include "qemu/osdep.h"
#include "libqtest.h"
#include "libqos/pci-pc.h"
#include "qemu/sockets.h"
#include "qemu/iov.h"
#include "qemu/module.h"
#include "qemu/bitops.h"
#include "libqos/malloc.h"
#include "libqos/qgraph.h"
#include "e1000e.h"

#define E1000E_IMS      (0x00d0)

#define E1000E_STATUS   (0x0008)
#define E1000E_STATUS_LU BIT(1)
#define E1000E_STATUS_ASDV1000 BIT(9)

#define E1000E_CTRL     (0x0000)
#define E1000E_CTRL_RESET BIT(26)

#define E1000E_RCTL     (0x0100)
#define E1000E_RCTL_EN  BIT(1)
#define E1000E_RCTL_UPE BIT(3)
#define E1000E_RCTL_MPE BIT(4)

#define E1000E_RFCTL     (0x5008)
#define E1000E_RFCTL_EXTEN  BIT(15)

#define E1000E_TCTL     (0x0400)
#define E1000E_TCTL_EN  BIT(1)

#define E1000E_CTRL_EXT             (0x0018)
#define E1000E_CTRL_EXT_DRV_LOAD    BIT(28)
#define E1000E_CTRL_EXT_TXLSFLOW    BIT(22)

#define E1000E_IVAR                 (0x00E4)
#define E1000E_IVAR_TEST_CFG        ((E1000E_RX0_MSG_ID << 0)    | BIT(3)  | \
                                     (E1000E_TX0_MSG_ID << 8)    | BIT(11) | \
                                     (E1000E_OTHER_MSG_ID << 16) | BIT(19) | \
                                     BIT(31))

#define E1000E_RING_LEN             (0x1000)

#define E1000E_TDBAL    (0x3800)

#define E1000E_TDBAH    (0x3804)
#define E1000E_TDH      (0x3810)

#define E1000E_RDBAL    (0x2800)
#define E1000E_RDBAH    (0x2804)
#define E1000E_RDH      (0x2810)

#define E1000E_TXD_LEN              (16)
#define E1000E_RXD_LEN              (16)

static void e1000e_macreg_write(QE1000E *d, uint32_t reg, uint32_t val)
{
    QE1000E_PCI *d_pci = container_of(d, QE1000E_PCI, e1000e);
    qpci_io_writel(&d_pci->pci_dev, d_pci->mac_regs, reg, val);
}

static uint32_t e1000e_macreg_read(QE1000E *d, uint32_t reg)
{
    QE1000E_PCI *d_pci = container_of(d, QE1000E_PCI, e1000e);
    return qpci_io_readl(&d_pci->pci_dev, d_pci->mac_regs, reg);
}

void e1000e_tx_ring_push(QE1000E *d, void *descr)
{
    uint32_t tail = e1000e_macreg_read(d, E1000E_TDT);
    uint32_t len = e1000e_macreg_read(d, E1000E_TDLEN) / E1000E_TXD_LEN;

    memwrite(d->tx_ring + tail * E1000E_TXD_LEN, descr, E1000E_TXD_LEN);
    e1000e_macreg_write(d, E1000E_TDT, (tail + 1) % len);

    /* Read WB data for the packet transmitted */
    memread(d->tx_ring + tail * E1000E_TXD_LEN, descr, E1000E_TXD_LEN);
}

void e1000e_rx_ring_push(QE1000E *d, void *descr)
{
    uint32_t tail = e1000e_macreg_read(d, E1000E_RDT);
    uint32_t len = e1000e_macreg_read(d, E1000E_RDLEN) / E1000E_RXD_LEN;

    memwrite(d->rx_ring + tail * E1000E_RXD_LEN, descr, E1000E_RXD_LEN);
    e1000e_macreg_write(d, E1000E_RDT, (tail + 1) % len);

    /* Read WB data for the packet received */
    memread(d->rx_ring + tail * E1000E_RXD_LEN, descr, E1000E_RXD_LEN);
}

static void e1000e_foreach_callback(QPCIDevice *dev, int devfn, void *data)
{
    QPCIDevice *res = data;
    memcpy(res, dev, sizeof(QPCIDevice));
    g_free(dev);
}

void e1000e_wait_isr(QE1000E *d, uint16_t msg_id)
{
    QE1000E_PCI *d_pci = container_of(d, QE1000E_PCI, e1000e);
    guint64 end_time = g_get_monotonic_time() + 5 * G_TIME_SPAN_SECOND;

    do {
        if (qpci_msix_pending(&d_pci->pci_dev, msg_id)) {
            return;
        }
        clock_step(10000);
    } while (g_get_monotonic_time() < end_time);

    g_error("Timeout expired");
}

static void e1000e_pci_destructor(QOSGraphObject *obj)
{
    QE1000E_PCI *epci = (QE1000E_PCI *) obj;
    qpci_iounmap(&epci->pci_dev, epci->mac_regs);
    qpci_msix_disable(&epci->pci_dev);
}

static void e1000e_pci_start_hw(QOSGraphObject *obj)
{
    QE1000E_PCI *d = (QE1000E_PCI *) obj;
    uint32_t val;

    /* Enable the device */
    qpci_device_enable(&d->pci_dev);

    /* Reset the device */
    val = e1000e_macreg_read(&d->e1000e, E1000E_CTRL);
    e1000e_macreg_write(&d->e1000e, E1000E_CTRL, val | E1000E_CTRL_RESET);

    /* Enable and configure MSI-X */
    qpci_msix_enable(&d->pci_dev);
    e1000e_macreg_write(&d->e1000e, E1000E_IVAR, E1000E_IVAR_TEST_CFG);

    /* Check the device status - link and speed */
    val = e1000e_macreg_read(&d->e1000e, E1000E_STATUS);
    g_assert_cmphex(val & (E1000E_STATUS_LU | E1000E_STATUS_ASDV1000),
        ==, E1000E_STATUS_LU | E1000E_STATUS_ASDV1000);

    /* Initialize TX/RX logic */
    e1000e_macreg_write(&d->e1000e, E1000E_RCTL, 0);
    e1000e_macreg_write(&d->e1000e, E1000E_TCTL, 0);

    /* Notify the device that the driver is ready */
    val = e1000e_macreg_read(&d->e1000e, E1000E_CTRL_EXT);
    e1000e_macreg_write(&d->e1000e, E1000E_CTRL_EXT,
        val | E1000E_CTRL_EXT_DRV_LOAD | E1000E_CTRL_EXT_TXLSFLOW);

    e1000e_macreg_write(&d->e1000e, E1000E_TDBAL,
                           (uint32_t) d->e1000e.tx_ring);
    e1000e_macreg_write(&d->e1000e, E1000E_TDBAH,
                           (uint32_t) (d->e1000e.tx_ring >> 32));
    e1000e_macreg_write(&d->e1000e, E1000E_TDLEN, E1000E_RING_LEN);
    e1000e_macreg_write(&d->e1000e, E1000E_TDT, 0);
    e1000e_macreg_write(&d->e1000e, E1000E_TDH, 0);

    /* Enable transmit */
    e1000e_macreg_write(&d->e1000e, E1000E_TCTL, E1000E_TCTL_EN);
    e1000e_macreg_write(&d->e1000e, E1000E_RDBAL,
                           (uint32_t)d->e1000e.rx_ring);
    e1000e_macreg_write(&d->e1000e, E1000E_RDBAH,
                           (uint32_t)(d->e1000e.rx_ring >> 32));
    e1000e_macreg_write(&d->e1000e, E1000E_RDLEN, E1000E_RING_LEN);
    e1000e_macreg_write(&d->e1000e, E1000E_RDT, 0);
    e1000e_macreg_write(&d->e1000e, E1000E_RDH, 0);

    /* Enable receive */
    e1000e_macreg_write(&d->e1000e, E1000E_RFCTL, E1000E_RFCTL_EXTEN);
    e1000e_macreg_write(&d->e1000e, E1000E_RCTL, E1000E_RCTL_EN  |
                                        E1000E_RCTL_UPE |
                                        E1000E_RCTL_MPE);

    /* Enable all interrupts */
    e1000e_macreg_write(&d->e1000e, E1000E_IMS, 0xFFFFFFFF);

}

static void *e1000e_pci_get_driver(void *obj, const char *interface)
{
    QE1000E_PCI *epci = obj;
    if (!g_strcmp0(interface, "e1000e-if")) {
        return &epci->e1000e;
    }

    /* implicit contains */
    if (!g_strcmp0(interface, "pci-device")) {
        return &epci->pci_dev;
    }

    fprintf(stderr, "%s not present in e1000e\n", interface);
    g_assert_not_reached();
}

static void *e1000e_pci_create(void *pci_bus, QGuestAllocator *alloc,
                               void *addr)
{
    QE1000E_PCI *d = g_new0(QE1000E_PCI, 1);
    QPCIBus *bus = pci_bus;
    QPCIAddress *address = addr;

    qpci_device_foreach(bus, address->vendor_id, address->device_id,
                        e1000e_foreach_callback, &d->pci_dev);

    /* Map BAR0 (mac registers) */
    d->mac_regs = qpci_iomap(&d->pci_dev, 0, NULL);

    /* Allocate and setup TX ring */
    d->e1000e.tx_ring = guest_alloc(alloc, E1000E_RING_LEN);
    g_assert(d->e1000e.tx_ring != 0);

    /* Allocate and setup RX ring */
    d->e1000e.rx_ring = guest_alloc(alloc, E1000E_RING_LEN);
    g_assert(d->e1000e.rx_ring != 0);

    d->obj.get_driver = e1000e_pci_get_driver;
    d->obj.start_hw = e1000e_pci_start_hw;
    d->obj.destructor = e1000e_pci_destructor;

    return &d->obj;
}

static void e1000e_register_nodes(void)
{
    QPCIAddress addr = {
        .vendor_id = 0x8086,
        .device_id = 0x10D3,
    };

    /* FIXME: every test using this node needs to setup a -netdev socket,id=hs0
     * otherwise QEMU is not going to start */
    QOSGraphEdgeOptions opts = {
        .extra_device_opts = "netdev=hs0",
    };
    add_qpci_address(&opts, &addr);

    qos_node_create_driver("e1000e", e1000e_pci_create);
    qos_node_consumes("e1000e", "pci-bus", &opts);
}

libqos_init(e1000e_register_nodes);