linux-toradex.git/include/linux/virtio_config.h, branch v4.1.1

virtio: drop a useless config read

2015-04-01T04:07:14+00:00

    "virtio: core support for config generation"
fixed reading up 64 bit values, adding generation
checks for such reads.

By mistake, it left an explicit get call in place
as well. the result is that the value is read twice,
the first result is discarded.

Not a big deal since this only happens with virtio
blk and only on boot ATM, so performance isn't
affected, but let's clean it up.

Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Cornelia Huck 
Signed-off-by: Rusty Russell

virtio_config: reorder functions

2015-04-01T04:07:13+00:00

This simply reorders functions in virtio_config
so width access wrapper helpers are all together.
Drops an extra empty line while we are at it.

Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Rusty Russell

virtio: core support for config generation

2014-12-14T16:21:31+00:00

virtio 1.0 spec says:

Drivers MUST NOT assume reads from fields greater than 32 bits wide are
atomic, nor are reads from multiple fields: drivers SHOULD read device
configuration space fields like so:
	u32 before, after;
	do {
		before = get_config_generation(device);
		// read config entry/entries.
		after = get_config_generation(device);
	} while (after != before);

Do exactly this, for transports that support it.

Signed-off-by: Michael S. Tsirkin

virtio_config: fix virtio_cread_bytes

2014-12-11T18:04:38+00:00

virtio_cread_bytes is implemented incorrectly in case length happens to
be 2,4 or 8 bytes: transports and devices will assume it's an integer
value that has to be converted to LE format.

Let's just do multiple 1-byte reads: this also makes life easier
for transports who only need to implement 1,2,4 and 8 byte reads.

Signed-off-by: Michael S. Tsirkin

virtio: allow finalize_features to fail

2014-12-09T14:32:32+00:00

This will make it easy for transports to validate features and return
failure.

Signed-off-by: Michael S. Tsirkin

virtio_config: endian conversion for v1.0

2014-12-09T10:05:25+00:00

We (ab)use virtio conversion functions for device-specific
config space accesses.

Based on original patches by Cornelia and Rusty.

Signed-off-by: Rusty Russell 
Signed-off-by: Cornelia Huck 
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: David Hildenbrand

virtio: memory access APIs

2014-12-09T10:05:24+00:00

virtio 1.0 makes all memory structures LE, so
we need APIs to conditionally do a byteswap on BE
architectures.

To make it easier to check code statically,
add virtio specific types for multi-byte integers
in memory.

Add low level wrappers that do a byteswap conditionally, these will be
useful e.g. for vhost.  Add high level wrappers that
query device endian-ness and act accordingly.

Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Cornelia Huck

virtio: add support for 64 bit features.

2014-12-09T10:05:24+00:00

Change u32 to u64, and use BIT_ULL and 1ULL everywhere.

Note: transports are unchanged, and only set low 32 bit.
This guarantees that no transport sets e.g. VERSION_1
by mistake without proper support.

Based on patch by Rusty.

Signed-off-by: Rusty Russell 
Signed-off-by: Cornelia Huck 
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: David Hildenbrand 
Reviewed-by: Cornelia Huck

virtio: use u32, not bitmap for features

2014-12-09T10:05:23+00:00

It seemed like a good idea to use bitmap for features
in struct virtio_device, but it's actually a pain,
and seems to become even more painful when we get more
than 32 feature bits.  Just change it to a u32 for now.

Based on patch by Rusty.

Suggested-by: David Hildenbrand 
Signed-off-by: Rusty Russell 
Signed-off-by: Cornelia Huck 
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Cornelia Huck

virtio: add low-level APIs for feature bits

2014-12-09T10:05:23+00:00

Add low level APIs to test/set/clear feature bits.
For use by transports, to make it easier to
write code independent of feature bit array format.

Note: APIs is prefixed with __ and has _bit suffix
to stress its low level nature.  It's for use by transports only:
drivers should use virtio_has_feature and never need to set/clear
features.

Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Cornelia Huck