src/drivers/bus/virtio-pci.c

   1 /* virtio-pci.c - pci interface for virtio interface
   2  *
   3  * (c) Copyright 2008 Bull S.A.S.
   4  *
   5  *  Author: Laurent Vivier <Laurent.Vivier@bull.net>
   6  *
   7  * some parts from Linux Virtio PCI driver
   8  *
   9  *  Copyright IBM Corp. 2007
  10  *  Authors: Anthony Liguori  <aliguori@us.ibm.com>
  11  *
  12  */
  13
  14 #include "etherboot.h"
  15 #include "gpxe/io.h"
  16 #include "gpxe/virtio-ring.h"
  17 #include "gpxe/virtio-pci.h"
  18
  19 int vp_find_vq(unsigned int ioaddr, int queue_index,
  20                struct vring_virtqueue *vq)
  21 {
  22    struct vring * vr = &vq->vring;
  23    u16 num;
  24
  25    /* select the queue */
  26
  27    outw(queue_index, ioaddr + VIRTIO_PCI_QUEUE_SEL);
  28
  29    /* check if the queue is available */
  30
  31    num = inw(ioaddr + VIRTIO_PCI_QUEUE_NUM);
  32    if (!num) {
  33            printf("ERROR: queue size is 0\n");
  34            return -1;
  35    }
  36
  37    if (num > MAX_QUEUE_NUM) {
  38            printf("ERROR: queue size %d > %d\n", num, MAX_QUEUE_NUM);
  39            return -1;
  40    }
  41
  42    /* check if the queue is already active */
  43
  44    if (inl(ioaddr + VIRTIO_PCI_QUEUE_PFN)) {
  45            printf("ERROR: queue already active\n");
  46            return -1;
  47    }
  48
  49    vq->queue_index = queue_index;
  50
  51    /* initialize the queue */
  52
  53    vring_init(vr, num, (unsigned char*)&vq->queue);
  54
  55    /* activate the queue
  56     *
  57     * NOTE: vr->desc is initialized by vring_init()
  58     */
  59
  60    outl((unsigned long)virt_to_phys(vr->desc) >> PAGE_SHIFT,
  61         ioaddr + VIRTIO_PCI_QUEUE_PFN);
  62
  63    return num;
  64 }