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virtio: simplify config mechanism.

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Previously we used a type/len pair within the config space, but this
seems overkill.  We now simply define a structure which represents the
layout in the config space: the config space can now only be extended
at the end.

The main driver-visible changes:
1) We indicate what fields are present with an explicit feature bit.
2) Virtqueues are explicitly numbered, and not in the config space.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
2008-02-04 23:49:56 -05:00
parent f35d9d8aae
commit a586d4f601
11 changed files with 278 additions and 279 deletions
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45
drivers/virtio/virtio.c
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@ -148,51 +148,6 @@ void unregister_virtio_device(struct virtio_device *dev)
}
EXPORT_SYMBOL_GPL(unregister_virtio_device);
int __virtio_config_val(struct virtio_device *vdev,
u8 type, void *val, size_t size)
{
void *token;
unsigned int len;
token = vdev->config->find(vdev, type, &len);
if (!token)
return -ENOENT;
if (len != size)
return -EIO;
vdev->config->get(vdev, token, val, size);
return 0;
}
EXPORT_SYMBOL_GPL(__virtio_config_val);
int virtio_use_bit(struct virtio_device *vdev,
void *token, unsigned int len, unsigned int bitnum)
{
unsigned long bits[16];
/* This makes it convenient to pass-through find() results. */
if (!token)
return 0;
/* bit not in range of this bitfield? */
if (bitnum * 8 >= len / 2)
return 0;
/* Giant feature bitfields are silly. */
BUG_ON(len > sizeof(bits));
vdev->config->get(vdev, token, bits, len);
if (!test_bit(bitnum, bits))
return 0;
/* Set acknowledge bit, and write it back. */
set_bit(bitnum + len * 8 / 2, bits);
vdev->config->set(vdev, token, bits, len);
return 1;
}
EXPORT_SYMBOL_GPL(virtio_use_bit);
static int virtio_init(void)
{
if (bus_register(&virtio_bus) != 0)