[tcp] Merge boolean flags into a single "flags" field

[gpxe.git] / src / drivers / net / virtio-net.c

/*
 * (c) Copyright 2010 Stefan Hajnoczi <stefanha@gmail.com>
 *
 * based on the Etherboot virtio-net driver
 *
 *  (c) Copyright 2008 Bull S.A.S.
 *
 *  Author: Laurent Vivier <Laurent.Vivier@bull.net>
 *
 * some parts from Linux Virtio PCI driver
 *
 *  Copyright IBM Corp. 2007
 *  Authors: Anthony Liguori  <aliguori@us.ibm.com>
 *
 *  some parts from Linux Virtio Ring
 *
 *  Copyright Rusty Russell IBM Corporation 2007
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <errno.h>
#include <stdlib.h>
#include <gpxe/list.h>
#include <gpxe/iobuf.h>
#include <gpxe/netdevice.h>
#include <gpxe/pci.h>
#include <gpxe/if_ether.h>
#include <gpxe/ethernet.h>
#include <gpxe/virtio-ring.h>
#include <gpxe/virtio-pci.h>
#include "virtio-net.h"

/*
 * Virtio network device driver
 *
 * Specification:
 * http://ozlabs.org/~rusty/virtio-spec/
 *
 * The virtio network device is supported by Linux virtualization software
 * including QEMU/KVM and lguest.  This driver supports the virtio over PCI
 * transport; virtual machines have one virtio-net PCI adapter per NIC.
 *
 * Virtio-net is different from hardware NICs because virtio devices
 * communicate with the hypervisor via virtqueues, not traditional descriptor
 * rings.  Virtqueues are unordered queues, they support add_buf() and
 * get_buf() operations.  To transmit a packet, the driver has to add the
 * packet buffer onto the virtqueue.  To receive a packet, the driver must
 * first add an empty buffer to the virtqueue and then get the filled packet
 * buffer on completion.
 *
 * Virtqueues are an abstraction that is commonly implemented using the vring
 * descriptor ring layout.  The vring is the actual shared memory structure
 * that allows the virtual machine to communicate buffers with the hypervisor.
 * Because the vring layout is optimized for flexibility and performance rather
 * than space, it is heavy-weight and allocated like traditional descriptor
 * rings in the open() function of the driver and not in probe().
 *
 * There is no true interrupt enable/disable.  Virtqueues have callback
 * enable/disable flags but these are only hints.  The hypervisor may still
 * raise an interrupt.  Nevertheless, this driver disables callbacks in the
 * hopes of avoiding interrupts.
 */

/* Driver types are declared here so virtio-net.h can be easily synced with its
 * Linux source.
 */

/* Virtqueue indicies */
enum {
        RX_INDEX = 0,
        TX_INDEX,
        QUEUE_NB
};

enum {
        /** Max number of pending rx packets */
        NUM_RX_BUF = 8,

        /** Max Ethernet frame length, including FCS and VLAN tag */
        RX_BUF_SIZE = 1522,
};

struct virtnet_nic {
        /** Base pio register address */
        unsigned long ioaddr;

        /** RX/TX virtqueues */
        struct vring_virtqueue *virtqueue;

        /** RX packets handed to the NIC waiting to be filled in */
        struct list_head rx_iobufs;

        /** Pending rx packet count */
        unsigned int rx_num_iobufs;

        /** Virtio net packet header, we only need one */
        struct virtio_net_hdr empty_header;
};

/** Add an iobuf to a virtqueue
 *
 * @v netdev            Network device
 * @v vq_idx            Virtqueue index (RX_INDEX or TX_INDEX)
 * @v iobuf             I/O buffer
 *
 * The virtqueue is kicked after the iobuf has been added.
 */
static void virtnet_enqueue_iob ( struct net_device *netdev,
                                  int vq_idx, struct io_buffer *iobuf ) {
        struct virtnet_nic *virtnet = netdev->priv;
        struct vring_virtqueue *vq = &virtnet->virtqueue[vq_idx];
        unsigned int out = ( vq_idx == TX_INDEX ) ? 2 : 0;
        unsigned int in = ( vq_idx == TX_INDEX ) ? 0 : 2;
        struct vring_list list[] = {
                {
                        /* Share a single zeroed virtio net header between all
                         * rx and tx packets.  This works because this driver
                         * does not use any advanced features so none of the
                         * header fields get used.
                         */
                        .addr = ( char* ) &virtnet->empty_header,
                        .length = sizeof ( virtnet->empty_header ),
                },
                {
                        .addr = ( char* ) iobuf->data,
                        .length = iob_len ( iobuf ),
                },
        };

        DBGC ( virtnet, "VIRTIO-NET %p enqueuing iobuf %p on vq %d\n",
               virtnet, iobuf, vq_idx );

        vring_add_buf ( vq, list, out, in, iobuf, 0 );
        vring_kick ( virtnet->ioaddr, vq, 1 );
}

/** Try to keep rx virtqueue filled with iobufs
 *
 * @v netdev            Network device
 */
static void virtnet_refill_rx_virtqueue ( struct net_device *netdev ) {
        struct virtnet_nic *virtnet = netdev->priv;

        while ( virtnet->rx_num_iobufs < NUM_RX_BUF ) {
                struct io_buffer *iobuf;

                /* Try to allocate a buffer, stop for now if out of memory */
                iobuf = alloc_iob ( RX_BUF_SIZE );
                if ( ! iobuf )
                        break;

                /* Keep track of iobuf so close() can free it */
                list_add ( &iobuf->list, &virtnet->rx_iobufs );

                /* Mark packet length until we know the actual size */
                iob_put ( iobuf, RX_BUF_SIZE );

                virtnet_enqueue_iob ( netdev, RX_INDEX, iobuf );
                virtnet->rx_num_iobufs++;
        }
}

/** Open network device
 *
 * @v netdev    Network device
 * @ret rc      Return status code
 */
static int virtnet_open ( struct net_device *netdev ) {
        struct virtnet_nic *virtnet = netdev->priv;
        unsigned long ioaddr = virtnet->ioaddr;
        u32 features;
        int i;

        /* Reset for sanity */
        vp_reset ( ioaddr );

        /* Allocate virtqueues */
        virtnet->virtqueue = zalloc ( QUEUE_NB *
                                      sizeof ( *virtnet->virtqueue ) );
        if ( ! virtnet->virtqueue )
                return -ENOMEM;

        /* Initialize rx/tx virtqueues */
        for ( i = 0; i < QUEUE_NB; i++ ) {
                if ( vp_find_vq ( ioaddr, i, &virtnet->virtqueue[i] ) == -1 ) {
                        DBGC ( virtnet, "VIRTIO-NET %p cannot register queue %d\n",
                               virtnet, i );
                        free ( virtnet->virtqueue );
                        virtnet->virtqueue = NULL;
                        return -ENOENT;
                }
        }

        /* Initialize rx packets */
        INIT_LIST_HEAD ( &virtnet->rx_iobufs );
        virtnet->rx_num_iobufs = 0;
        virtnet_refill_rx_virtqueue ( netdev );

        /* Disable interrupts before starting */
        netdev_irq ( netdev, 0 );

        /* Driver is ready */
        features = vp_get_features ( ioaddr );
        vp_set_features ( ioaddr, features & ( 1 << VIRTIO_NET_F_MAC ) );
        vp_set_status ( ioaddr, VIRTIO_CONFIG_S_DRIVER | VIRTIO_CONFIG_S_DRIVER_OK );
        return 0;
}

/** Close network device
 *
 * @v netdev    Network device
 */
static void virtnet_close ( struct net_device *netdev ) {
        struct virtnet_nic *virtnet = netdev->priv;
        struct io_buffer *iobuf;
        struct io_buffer *next_iobuf;

        vp_reset ( virtnet->ioaddr );

        /* Virtqueues can be freed now that NIC is reset */
        free ( virtnet->virtqueue );
        virtnet->virtqueue = NULL;

        /* Free rx iobufs */
        list_for_each_entry_safe ( iobuf, next_iobuf, &virtnet->rx_iobufs, list ) {
                free_iob ( iobuf );
        }
        INIT_LIST_HEAD ( &virtnet->rx_iobufs );
        virtnet->rx_num_iobufs = 0;
}

/** Transmit packet
 *
 * @v netdev    Network device
 * @v iobuf     I/O buffer
 * @ret rc      Return status code
 */
static int virtnet_transmit ( struct net_device *netdev,
                              struct io_buffer *iobuf ) {
        virtnet_enqueue_iob ( netdev, TX_INDEX, iobuf );
        return 0;
}

/** Complete packet transmission
 *
 * @v netdev    Network device
 */
static void virtnet_process_tx_packets ( struct net_device *netdev ) {
        struct virtnet_nic *virtnet = netdev->priv;
        struct vring_virtqueue *tx_vq = &virtnet->virtqueue[TX_INDEX];

        while ( vring_more_used ( tx_vq ) ) {
                struct io_buffer *iobuf = vring_get_buf ( tx_vq, NULL );

                DBGC ( virtnet, "VIRTIO-NET %p tx complete iobuf %p\n",
                       virtnet, iobuf );

                netdev_tx_complete ( netdev, iobuf );
        }
}

/** Complete packet reception
 *
 * @v netdev    Network device
 */
static void virtnet_process_rx_packets ( struct net_device *netdev ) {
        struct virtnet_nic *virtnet = netdev->priv;
        struct vring_virtqueue *rx_vq = &virtnet->virtqueue[RX_INDEX];

        while ( vring_more_used ( rx_vq ) ) {
                unsigned int len;
                struct io_buffer *iobuf = vring_get_buf ( rx_vq, &len );

                /* Release ownership of iobuf */
                list_del ( &iobuf->list );
                virtnet->rx_num_iobufs--;

                /* Update iobuf length */
                iob_unput ( iobuf, RX_BUF_SIZE );
                iob_put ( iobuf, len - sizeof ( struct virtio_net_hdr ) );

                DBGC ( virtnet, "VIRTIO-NET %p rx complete iobuf %p len %zd\n",
                       virtnet, iobuf, iob_len ( iobuf ) );

                /* Pass completed packet to the network stack */
                netdev_rx ( netdev, iobuf );
        }

        virtnet_refill_rx_virtqueue ( netdev );
}

/** Poll for completed and received packets
 *
 * @v netdev    Network device
 */
static void virtnet_poll ( struct net_device *netdev ) {
        struct virtnet_nic *virtnet = netdev->priv;

        /* Acknowledge interrupt.  This is necessary for UNDI operation and
         * interrupts that are raised despite VRING_AVAIL_F_NO_INTERRUPT being
         * set (that flag is just a hint and the hypervisor not not have to
         * honor it).
         */
        vp_get_isr ( virtnet->ioaddr );

        virtnet_process_tx_packets ( netdev );
        virtnet_process_rx_packets ( netdev );
}

/** Enable or disable interrupts
 *
 * @v netdev    Network device
 * @v enable    Interrupts should be enabled
 */
static void virtnet_irq ( struct net_device *netdev, int enable ) {
        struct virtnet_nic *virtnet = netdev->priv;
        int i;

        for ( i = 0; i < QUEUE_NB; i++ ) {
                if ( enable )
                        vring_enable_cb ( &virtnet->virtqueue[i] );
                else
                        vring_disable_cb ( &virtnet->virtqueue[i] );
        }
}

/** virtio-net device operations */
static struct net_device_operations virtnet_operations = {
        .open = virtnet_open,
        .close = virtnet_close,
        .transmit = virtnet_transmit,
        .poll = virtnet_poll,
        .irq = virtnet_irq,
};

/**
 * Probe PCI device
 *
 * @v pci       PCI device
 * @v id        PCI ID
 * @ret rc      Return status code
 */
static int virtnet_probe ( struct pci_device *pci,
                           const struct pci_device_id *id __unused ) {
        unsigned long ioaddr = pci->ioaddr;
        struct net_device *netdev;
        struct virtnet_nic *virtnet;
        u32 features;
        int rc;

        /* Allocate and hook up net device */
        netdev = alloc_etherdev ( sizeof ( *virtnet ) );
        if ( ! netdev )
                return -ENOMEM;
        netdev_init ( netdev, &virtnet_operations );
        virtnet = netdev->priv;
        virtnet->ioaddr = ioaddr;
        pci_set_drvdata ( pci, netdev );
        netdev->dev = &pci->dev;

        DBGC ( virtnet, "VIRTIO-NET %p busaddr=%s ioaddr=%#lx irq=%d\n",
               virtnet, pci->dev.name, ioaddr, pci->irq );

        /* Enable PCI bus master and reset NIC */
        adjust_pci_device ( pci );
        vp_reset ( ioaddr );

        /* Load MAC address */
        features = vp_get_features ( ioaddr );
        if ( features & ( 1 << VIRTIO_NET_F_MAC ) ) {
                vp_get ( ioaddr, offsetof ( struct virtio_net_config, mac ),
                         netdev->hw_addr, ETH_ALEN );
                DBGC ( virtnet, "VIRTIO-NET %p mac=%s\n", virtnet,
                       eth_ntoa ( netdev->hw_addr ) );
        }

        /* Mark link as up, control virtqueue is not used */
        netdev_link_up ( netdev );

        if ( ( rc = register_netdev ( netdev ) ) != 0 ) {
                vp_reset ( ioaddr );
                netdev_nullify ( netdev );
                netdev_put ( netdev );
        }
        return rc;
}

/**
 * Remove device
 *
 * @v pci       PCI device
 */
static void virtnet_remove ( struct pci_device *pci ) {
        struct net_device *netdev = pci_get_drvdata ( pci );

        unregister_netdev ( netdev );
        netdev_nullify ( netdev );
        netdev_put ( netdev );
}

static struct pci_device_id virtnet_nics[] = {
PCI_ROM(0x1af4, 0x1000, "virtio-net", "Virtio Network Interface", 0),
};

struct pci_driver virtnet_driver __pci_driver = {
        .ids = virtnet_nics,
        .id_count = ( sizeof ( virtnet_nics ) / sizeof ( virtnet_nics[0] ) ),
        .probe = virtnet_probe,
        .remove = virtnet_remove,
};