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/******************************************************************************
* Copyright (c) 2012 IBM Corporation
* All rights reserved.
* This program and the accompanying materials
* are made available under the terms of the BSD License
* which accompanies this distribution, and is available at
* http://www.opensource.org/licenses/bsd-license.php
*
* Contributors:
* IBM Corporation - initial implementation
*****************************************************************************/
#include <stdio.h>
#include <string.h>
#include <cpu.h>
#include <helpers.h>
#include "virtio.h"
#include "virtio-internal.h"
#include "virtio-scsi.h"
int virtioscsi_send(struct virtio_device *dev,
struct virtio_scsi_req_cmd *req,
struct virtio_scsi_resp_cmd *resp,
int is_read, void *buf, uint64_t buf_len)
{
struct vring_desc *vq_desc; /* Descriptor vring */
struct vring_avail *vq_avail; /* "Available" vring */
struct vring_used *vq_used; /* "Used" vring */
volatile uint16_t *current_used_idx;
uint16_t last_used_idx, avail_idx;
int id;
uint32_t vq_size, time;
int vq = VIRTIO_SCSI_REQUEST_VQ;
vq_size = virtio_get_qsize(dev, vq);
vq_desc = virtio_get_vring_desc(dev, vq);
vq_avail = virtio_get_vring_avail(dev, vq);
vq_used = virtio_get_vring_used(dev, vq);
avail_idx = virtio_modern16_to_cpu(dev, vq_avail->idx);
last_used_idx = vq_used->idx;
current_used_idx = &vq_used->idx;
/* Determine descriptor index */
id = (avail_idx * 3) % vq_size;
virtio_fill_desc(&vq_desc[id], dev->is_modern, (uint64_t)req, sizeof(*req), VRING_DESC_F_NEXT,
(id + 1) % vq_size);
/* Set up virtqueue descriptor for data */
if (buf && buf_len) {
virtio_fill_desc(&vq_desc[(id + 1) % vq_size], dev->is_modern,
(uint64_t)resp, sizeof(*resp),
VRING_DESC_F_NEXT | VRING_DESC_F_WRITE,
(id + 2) % vq_size);
/* Set up virtqueue descriptor for status */
virtio_fill_desc(&vq_desc[(id + 2) % vq_size], dev->is_modern,
(uint64_t)buf, buf_len,
(is_read ? VRING_DESC_F_WRITE : 0), 0);
} else {
virtio_fill_desc(&vq_desc[(id + 1) % vq_size], dev->is_modern,
(uint64_t)resp, sizeof(*resp),
VRING_DESC_F_WRITE, 0);
}
vq_avail->ring[avail_idx % vq_size] = virtio_cpu_to_modern16(dev, id);
mb();
vq_avail->idx = virtio_cpu_to_modern16(dev, avail_idx + 1);
/* Tell HV that the vq is ready */
virtio_queue_notify(dev, vq);
/* Wait for host to consume the descriptor */
time = SLOF_GetTimer() + VIRTIO_TIMEOUT;
while (*current_used_idx == last_used_idx) {
// do something better
mb();
if (time < SLOF_GetTimer())
break;
}
return 0;
}
/**
* Initialize virtio-block device.
* @param dev pointer to virtio device information
*/
int virtioscsi_init(struct virtio_device *dev)
{
struct vring_avail *vq_avail;
unsigned int idx = 0;
int qsize = 0;
int status = VIRTIO_STAT_ACKNOWLEDGE;
/* Reset device */
// XXX That will clear the virtq base. We need to move
// initializing it to here anyway
//
// virtio_reset_device(dev);
/* Acknowledge device. */
virtio_set_status(dev, status);
/* Tell HV that we know how to drive the device. */
status |= VIRTIO_STAT_DRIVER;
virtio_set_status(dev, status);
/* Device specific setup - we do not support special features right now */
if (dev->is_modern) {
if (virtio_negotiate_guest_features(dev, VIRTIO_F_VERSION_1))
goto dev_error;
virtio_get_status(dev, &status);
} else {
virtio_set_guest_features(dev, 0);
}
while(1) {
qsize = virtio_get_qsize(dev, idx);
if (!qsize)
break;
virtio_vring_size(qsize);
vq_avail = virtio_get_vring_avail(dev, idx);
vq_avail->flags = virtio_cpu_to_modern16(dev, VRING_AVAIL_F_NO_INTERRUPT);
vq_avail->idx = 0;
idx++;
}
/* Tell HV that setup succeeded */
status |= VIRTIO_STAT_DRIVER_OK;
virtio_set_status(dev, status);
return 0;
dev_error:
printf("%s: failed\n", __func__);
status |= VIRTIO_STAT_FAILED;
virtio_set_status(dev, status);
return -1;
}
/**
* Shutdown the virtio-block device.
* @param dev pointer to virtio device information
*/
void virtioscsi_shutdown(struct virtio_device *dev)
{
/* Quiesce device */
virtio_set_status(dev, VIRTIO_STAT_FAILED);
/* Reset device */
virtio_reset_device(dev);
}
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