Rpmsg echo example for ADI sc5xx-sharc platforms.

The example shows how to use rpmsg endpoints to communicate between ARM and other SHARC cores. The example uses fork of rpmsg-lite library by NXP with adsp-sc5xx-sharc platform support added (feature/add_sc5xx_sharc_platform branch).

• Rpmsg-lite documentation: https://nxpmicro.github.io/rpmsg-lite/index.html.

Rpmsg-lite integration into a CCES project

1. Create CCES project for sc5xx-sharc platform.
2. Remove MCAPI module, add TRU module.
3. Include rpmsg-lite dir into the project, as a git submodule, copy of the rpmsg-lite dir or as a link to the rpmsg-lite dir.
4. In the project exclude from build unused platforms and features:
   • exclude all dirs from rpmsg-lite/lib/include/platform except adsp-sc5xx-sharc
   • exclude all dirs files from rpmsg-lite/lib/rpmsg_lite/porting/platform except adsp-sc5xx-sharc
   • exclude all *.c files from rpmsg-lite/lib/rpmsg_lite/porting/environment except rpmsg_env_bm.c
   • exclude rpmsg_queue.c file from rpmsg-lite/lib/rpmsg_lite
5. Create rpmsg_config.h file which defines rpmsg-lite configuration. In the file define #define RL_USE_STATIC_API (1), currently only static API is supported on sc5xx-sharc platform.
6. Add paths to include directories for all build configurations (DEBUG and RELEASE):
   • dir containing newly created rpmsg_config.h
   • rpmsg-lite/lib/include
   • rpmsg-lite/lib/include/platform/adsp-sc5xx-sharc
7. If you plan to load sharc firmware using remoteproc from Linux configure project to produce ldr file:
   • ADI remoteproc wiki
   • Steps to configure CCES project for LDR binary file

Echo example usage

Initialization

Using Linux command line start cores with the echo example. The example firmware announces created endpoints on rpmsg bus, Linux creates a rpmsg device for each endpoint in /sys/bus/rpmsg/devices To communicate to the endpoints from userspace kernel must be compiled with CONFIG_RPMSG_CHAR which enables rpmsg-char driver. Bind a rpmsg device to the driver manually or using rpmsg-bind-chardev which is a helper application for binding rpmsg devices to the rpmsg-char driver. It can be found in the rpmsg-utils package from meta-adi Yocto layer. The bind creates a /dev/rpmsgX file which an user space application can use to communicate with an endpoint created in SHARC firmware.

SHARC Core1 initialization script for the echo example:

#!/bin/sh
echo echo_core1.ldr > /sys/class/remoteproc/remoteproc0/firmware
echo start > /sys/class/remoteproc/remoteproc0/state

rpmsg-bind-chardev -p virtio0.sharc-echo.-1. -n 1 -e 151 -s 50

rpmsg-bind-chardev -p virtio0.sharc-echo-cap.-1. -n 1 -e 161 -s 61

SHARC Core2 initialization script for the echo example:

#!/bin/sh
echo echo_core2.ldr > /sys/class/remoteproc/remoteproc1/firmware
echo start > /sys/class/remoteproc/remoteproc1/state

rpmsg-bind-chardev -p virtio1.sharc-echo.-1. -n 1 -e 152 -s 51

rpmsg-bind-chardev -p virtio1.sharc-echo-cap.-1. -n 1 -e 162 -s 62

Communicate

It is possible to send a messages to an endpoint on SHARC using regular echo

root@adsp-sc594-som-ezkit:~# echo "Hello!" > /dev/rpmsg0

But the messages coming from the endpoint are being dropped if the /dev/rpmsg0 file is closed. Therefore the rpmsg-utils package also contains an rpmsg-xmit helper application which reads a message from stdin, writes it to the /dev/rpmsgX file, while keeping the file open reads response and prints on stdout.

root@adsp-sc594-som-ezkit:~# echo hello | rpmsg-xmit -n 5 /dev/rpmsg0
hello => echo from Core1
root@adsp-sc594-som-ezkit:~# echo hello | rpmsg-xmit -n 5 /dev/rpmsg1
HELLO => capitalized echo from Core1
root@adsp-sc594-som-ezkit:~# echo hello | rpmsg-xmit -n 5 /dev/rpmsg2
hello => echo from Core2
root@adsp-sc594-som-ezkit:~# echo hello | rpmsg-xmit -n 5 /dev/rpmsg3
HELLO => capitalized echo from Core2