This driver allows rpmsg instances to expose access to rpmsg endpoints
to user space processes. It provides a control interface, allowing
userspace to export endpoints and an endpoint interface for each exposed
endpoint.
The implementation is based on prior art by Texas Instrument, Google,
PetaLogix and was derived from a FreeRTOS performance statistics driver
written by Michal Simek.
The control interface provides a "create endpoint" ioctl, which is fed a
name, source and destination address. The three values are used to
create the endpoint, in a backend-specific way, and a rpmsg endpoint
device is created - with the three parameters are available in sysfs for
udev usage.
E.g. to create an endpoint device for one of the Qualcomm SMD channel
related to DIAG one would issue:
struct rpmsg_endpoint_info info = { "DIAG_CNTL", 0, 0 };
int fd = open("/dev/rpmsg_ctrl0", O_RDWR);
ioctl(fd, RPMSG_CREATE_EPT_IOCTL, &info);
Each created endpoint device shows up as an individual character device
in /dev, allowing permission to be controlled on a per-endpoint basis.
The rpmsg endpoint will be created and destroyed following the opening
and closing of the endpoint device, allowing rpmsg backends to open and
close the physical channel, if supported by the wire protocol.
Cc: Marek Novak <marek.novak@nxp.com>
Cc: Matteo Sartori <matteo.sartori@t3lab.it>
Cc: Michal Simek <monstr@monstr.eu>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
This introduces a new rpmsg backend for the Qualcomm SMD system,
allowing communication with various remote processors found in Qualcomm
platforms. The implementation is based on, and intends to replace,
drivers/soc/qcom/smd.c with the necessary adaptions for fitting with the
rpmsg core.
Based on original work by Sricharan R <sricharan@codeaurora.org>
Cc: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Extract the now indirect rpmsg_create_ept() interface to a separate
file and start building up a rpmsg core.
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Add a virtio-based inter-processor communication bus, which enables
kernel drivers to communicate with entities, running on remote
processors, over shared memory using a simple messaging protocol.
Every pair of AMP processors share two vrings, which are used to send
and receive the messages over shared memory.
The header of every message sent on the rpmsg bus contains src and dst
addresses, which make it possible to multiplex several rpmsg channels on
the same vring.
Every rpmsg channel is a device on this bus. When a channel is added,
and an appropriate rpmsg driver is found and probed, it is also assigned
a local rpmsg address, which is then bound to the driver's callback.
When inbound messages carry the local address of a bound driver,
its callback is invoked by the bus.
This patch provides a kernel interface only; user space interfaces
will be later exposed by kernel users of this rpmsg bus.
Designed with Brian Swetland <swetland@google.com>.
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au> (virtio_ids.h)
Cc: Brian Swetland <swetland@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg KH <greg@kroah.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
