Commit 0d2e1a29 authored by Erwan Yvin's avatar Erwan Yvin Committed by Rusty Russell
Browse files

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: default avatarErwan Yvin <erwan.yvin@stericsson.com>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (minor fixes)
parent 3beee86a

drivers/net/caif/Kconfig

+14 −0
Original line number Diff line number Diff line
@@ -47,3 +47,17 @@ config CAIF_HSI 
       The caif low level driver for CAIF over HSI.

       Be aware that if you enable this then you also need to

       enable a low-level HSI driver.



config CAIF_VIRTIO

	tristate "CAIF virtio transport driver"

	depends on CAIF

	select VHOST_RING

	select VIRTIO

	select GENERIC_ALLOCATOR

	default n

	---help---

	The caif driver for CAIF over Virtio.



if CAIF_VIRTIO

source "drivers/vhost/Kconfig"

endif

drivers/net/caif/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -13,3 +13,6 @@ obj-$(CONFIG_CAIF_SHM) += caif_shm.o 


# HSI interface

obj-$(CONFIG_CAIF_HSI) += caif_hsi.o



# Virtio interface

obj-$(CONFIG_CAIF_VIRTIO) += caif_virtio.o

drivers/net/caif/caif_virtio.c

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+785 −0

File added.

Preview size limit exceeded, changes collapsed.

include/linux/virtio_caif.h

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+24 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) ST-Ericsson AB 2012

 * Author: Sjur Brændeland <sjur.brandeland@stericsson.com>

 *

 * This header is BSD licensed so

 * anyone can use the definitions to implement compatible remote processors

 */



#ifndef VIRTIO_CAIF_H

#define VIRTIO_CAIF_H



#include <linux/types.h>

struct virtio_caif_transf_config {

	u16 headroom;

	u16 tailroom;

	u32 mtu;

	u8 reserved[4];

};



struct virtio_caif_config {

	struct virtio_caif_transf_config uplink, downlink;

	u8 reserved[8];

};

#endif

include/uapi/linux/virtio_ids.h

+1 −0
Original line number Diff line number Diff line
@@ -38,5 +38,6 @@ 
#define VIRTIO_ID_SCSI		8 /* virtio scsi */

#define VIRTIO_ID_9P		9 /* 9p virtio console */

#define VIRTIO_ID_RPROC_SERIAL 11 /* virtio remoteproc serial link */

#define VIRTIO_ID_CAIF	       12 /* Virtio caif */



#endif /* _LINUX_VIRTIO_IDS_H */

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