drivers/rpmsg/ping: skip rpmsg ping send if endpoint is not ready

[anchao]

Summary

drivers/rpmsg/ping: skip rpmsg ping send if endpoint is not ready

rpmsg ping send blocks for 15 seconds until the ept is ready, which is not ideal for applications that need to monitor ping status. In this PR, we will check if the ept is ready to avoid prolonged blocking in the underlying driver.

Signed-off-by: chao an [email protected]

Impact

rpmsg ping ioctl

Testing

sim/rpproxy with rpmsg ping, qemu-armv8a(ivshmem) with rpmsg ping

[linguini1]

Can you include the logs from your tests?

[anchao]

Can you include the logs from your tests?

Thanks for reminding. I've been quite busy lately, so please hold this PR do not merge. I'll submit the log if feel free.