rpmsg: Move the rpmsg control device from rpmsg_char to rpmsg_ctrl

Create the rpmsg_ctrl.c module and move the code related to the
rpmsg_ctrldev device in this new module.

Add the dependency between rpmsg_char and rpmsg_ctrl in the
kconfig file:

1) RPMSG_CTRL can set as module or built-in if
RPMSG=y || RPMSG_CHAR=y || RPMSG_CHAR=n

2) RPMSG_CTRL can not be set as built-in if
RPMSG=m || RPMSG_CHAR=m

Note that RPMGH_CHAR and RPMSG_CTRL can be activated separately.
Therefore, the RPMSG_CTRL configuration must be set for backwards compatibility.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220124102524.295783-4-arnaud.pouliquen@foss.st.com

rpmsg: Turn name service into a stand alone driver

Make the RPMSG name service announcement a stand alone driver so that it
can be reused by other subsystems. It is also the first step in making the
functionatlity transport independent, i.e that is not tied to virtIO.

Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Tested-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Co-developed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Co-developed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Link: https://lore.kernel.org/r/20201120214245.172963-9-mathieu.poirier@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

rpmsg: glink: Integrate glink_ssr in qcom_glink

In all but the very special case of a system with _only_ glink_rpm,
GLINK is dependent on glink_ssr, so move it to rpmsg and combine it with
qcom_glink_native in the new qcom_glink kernel module.

Acked-by: Chris Lew <clew@codeaurora.org>
Acked-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
Link: https://lore.kernel.org/r/20200423003736.2027371-4-bjorn.andersson@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

rpmsg: add rpmsg support for mt8183 SCP.

Add a simple rpmsg support for mt8183 SCP, that use IPI / IPC directly.

Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
Link: https://lore.kernel.org/r/20191112110330.179649-4-pihsun@chromium.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

rpmsg: Fix Kconfig indentation

Adjust indentation from spaces to tab (+optional two spaces) as in
coding style with command like:
$ sed -e 's/^ /\t/' -i */Kconfig

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20191120133945.13938-1-krzk@kernel.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

rpmsg: Switch to SPDX license identifier

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>

rpmsg: qcom_smd: Access APCS through mailbox framework

Attempt to acquire the APCS IPC through the mailbox framework and fall
back to the old syscon based approach, to allow us to move away from
using the syscon.

Reviewed-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

rpmsg: Allow RPMSG_VIRTIO to be enabled via menuconfig or defconfig

Currently, RPMSG_VIRTIO can only be enabled if some other kconfig
option selects it. This does not allow it to be enabled for
virtualized systems where Virtio RPMSG is available over Virtio
MMIO or PCI transport.

This patch updates RPMSG_VIRTIO kconfig option so that we can
enable the VirtIO RPMSG driver via menuconfig or defconfig. The
patch also removes "select RPMSG_VIRTIO" from various remoteproc
kconfig options because it is now user selectable.

Signed-off-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

rpmsg: glink: Introduce glink smem based transport

The glink protocol supports different types of transports (shared
memory). With the core protocol remaining the same, the way the
transport's memory is probed and accessed is different. So add support
for glink's smem based transports.

Adding a new smem transport register function and the fifo accessors for
the same.

Acked-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

rpmsg: glink: Move the common glink protocol implementation to glink_native.c

Move the common part of glink core protocol implementation to
glink_native.c that can be shared with the smem based glink
transport in the later patches.

Acked-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

rpmsg: Drop VIRTUALIZATION dependency from RPMSG_VIRTIO

A dependency to VIRTUALIZATION has been added to RPMSG_VIRTIO (back
when it was named RPMSG) in v3.10 kernel in commit 397944df3290
("rpmsg: fix kconfig dependencies for VIRTIO") to resolve Kconfig
warnings due to the inclusion of the virtio configuration file from
the ARM's KVM config file. The KVM config was fixed properly in the
subsequent release in commit 8bd4ffd6b3a9 ("ARM: kvm: don't include
drivers/virtio/Kconfig"). So, drop this unneeded VIRTUALIZATION
dependency from RPMSG_VIRTIO.

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

rpmsg: Introduce Qualcomm RPM glink driver

This introduces a basic driver for communicating over "native glink"
with the RPM found in Qualcomm platforms.

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

soc: qcom: smd: Remove standalone driver

Remove the standalone SMD implementation as we have transitioned the
client drivers to use the RPMSG based one.

Also remove all dependencies on QCOM_SMD from Kconfig files, in order to
keep them selectable in the absence of the removed symbol.

Acked-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

rpmsg: char: add CONFIG_NET dependency

Without CONFIG_NET, we get a build failure for the new driver:

ERROR: "skb_queue_tail" [drivers/rpmsg/rpmsg_char.ko] undefined!
ERROR: "skb_put" [drivers/rpmsg/rpmsg_char.ko] undefined!
ERROR: "__alloc_skb" [drivers/rpmsg/rpmsg_char.ko] undefined!
ERROR: "kfree_skb" [drivers/rpmsg/rpmsg_char.ko] undefined!
ERROR: "skb_dequeue" [drivers/rpmsg/rpmsg_char.ko] undefined!

This adds a dependency so we don't try to build the broken configuration.

Fixes: c0cdc19f84a4 ("rpmsg: Driver for user space endpoint interface")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

rpmsg: Driver for user space endpoint interface

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>

rpmsg: smd: fix dependency on QCOM_SMD=n

The ARM allmodconfig build broke with the addition of the SMD rpmsg
driver that conflicts with the driver its replaces:

WARNING: drivers/soc/qcom/smd: 'qcom_smd_register_edge' exported twice. Previous export was in drivers/rpmsg/qcom_smd.ko
WARNING: drivers/soc/qcom/smd: 'qcom_smd_unregister_edge' exported twice. Previous export was in drivers/rpmsg/qcom_smd.ko

There is already a dependency that is meant to avoid the broken
configuration, but that only prevents the case where at least
one of the two are built-in, but not if both are modules.

This changes the dependency to "=n", to ensure that the new driver
can only be enabled if the other one is completely disabled.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 53e2822e56c7 ("rpmsg: Introduce Qualcomm SMD backend")
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

rpmsg: Introduce Qualcomm SMD backend

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>

rpmsg: Move rpmsg_device API to new file

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>

rpmsg: fix kconfig dependencies for VIRTIO

Fix this:
warning: (VIRTIO_PCI && VIRTIO_MMIO && REMOTEPROC && RPMSG) selects VIRTIO which has unmet direct dependencies (VIRTUALIZATION)

Cc: stable@vger.kernel.org
Signed-off-by: Suman Anna <s-anna@ti.com>
[edit commit log]
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

drivers/rpmsg: remove depends on CONFIG_EXPERIMENTAL

The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
while now and is almost always enabled by default. As agreed during the
Linux kernel summit, remove it from any "depends on" lines in Kconfigs.

CC: Ohad Ben-Cohen <ohad@wizery.com>
CC: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>

virtio: remove CONFIG_VIRTIO_RING

Everyone who selects VIRTIO is also made to select VIRTIO_RING; just make
them synonymous, since we removed the indirection layer some time ago.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

rpmsg: depend on EXPERIMENTAL

There isn't any binary change in sight or evidence of any stability
issue, but as we just begin to get traction we can't rule them out
completely.

To be on the safe side, let's mark rpmsg as EXPERIMENTAL, and remove
it later on after we have several happy users.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Rob Clark <rob@ti.com>
Cc: Mark Grosen <mgrosen@ti.com>
Cc: Ludovic BARRE <ludovic.barre@stericsson.com>

rpmsg: add Kconfig menu

Add a dedicated Kconfig menu for the rpmsg drivers, so they
don't show up in the main driver menu.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

rpmsg: add virtio-based remote processor messaging bus

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>