tree 29f6397b0f544c60bfdbc8d9ad0aae5337fc7532
parent 3beee86a4b9374e38dba36b44e81f1423a0d6b54
author Erwan Yvin <erwan.yvin@stericsson.com> 1363749744 +1030
committer Rusty Russell <rusty@rustcorp.com.au> 1363750566 +1030

caif_virtio: Introduce caif over virtio

Add the CAIF Virtio shared memory driver for talking
to a modem.

This CAIF Link layer communicates to the modem over
shared memory. It is implemented as a virtio_driver.
The underlying virtio device is managed by the remoteproc
framework. The Virtio queue is used for transmitting data
to the modem, and the new vringh is used for receiving data.

Genalloc is used for managing the shared memory used for TX
data. The default dma-alloc-coherent allocator can only
allocate whole pages, and this wastes too much shared memory.

Flow control is implemented by stopping the TX-queues if the
virtio queues go full or we run out of memory. Queued are
reopened when queues are below the watermark.

NAPI is used in RX path, and a dedicated tasklet is used
for releasing TX buffers.

Signed-off-by: Erwan Yvin <erwan.yvin@stericsson.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (minor fixes)