Minor typos, grammar and copy/paste issues. Fix for consistency. No
functional or semantic change.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Use the appropriate SPDX license identifier in the rpmsg core
source files and drop the previous boilerplate license text.

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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 allows rpmsg backends to implement polling of the outgoing buffer,
which provides poll support to user space when using the rpmsg character
device.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Move the device and endpoint indirection tables to the rpmsg internal
header file, to hide them from the public API.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Extract the generic rpmsg core functionality from the virtio rpmsg
implementation, splitting the implementation in a rpmsg core and a
virtio backend.

Based on initial work by Sricharan R <sricharan@codeaurora.org>

Cc: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Extract and move the helper function for finding rpmsg child devices to
the core.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>