Hi Arnaud,
On 24.02.22 09:29, Arnaud POULIQUEN wrote:
Hi Philipp,
On 2/23/22 22:28, Philipp Rossak wrote:
Hi Arnaud,
thanks for working on this! I'm currently testing/using this patch
series on my imx7d project because it adds the capability that the
remote processor can register it's endpoints dynamically (as mentioned
in the objectives).
Thanks for your feedback on this work!
Don't hesitate to add your tested-by, this help maintainers for the reviews.
I will do this.
After a few tests, debugging, and checking the openamp specification [1]
I think that you missed the second ns_announcement that should be sent
from linux master to the slave after it created the channel/endpoint.
Without this second announcement the remote processor is not able to
send messages to the linux master because it doesn't know the
destination address until it receives a message from the linux master.
Yes I detected this issues, it is not related to the series
but to the remoteproc_virtio backend.
As you mentioned, after the ns announcement from Linux, the remote processor
send first messages. But the Linux virtio does not do the match between the
local channel created and the remote endpoint.
I'm not sure if we talk about the same. I'm basically talking about the
dynamic binding, not dynamic endpoint creation.
I think I already found the issue. I will try to get a bit more into detail.
1. Linux: starts co-processor via remoteproc
2. co-processor: boots and reaches the point where it creates the
endpoint like it is done in this ST example[1].
Be aware the src address is RPMSG_ADDR_ANY
3. co-processor: reaches the point where it sends the ns_announcement to
linux ns endpoint
4. linux: receives the ns announcment, creates the channel, bindes the
endpoint and checks here [2] if the source address is not RPMSG_ADDR_ANY
and in this case it is not sending a ns_announcement (that's the issue
when we use dynamic endpoints)
5. linux: according the openamp spec [3] it should now send the
ns_announcement to the co-processor (slave)
6. co-processor: should receive the ns announcement and binds now the
endpoint
7. co-processor: can now send messages to linux
This is basically what I'm expecting.
Do you think this is a bug or is the dynamic endpoint binding not
handled? This line is there since ever [4] ...
Any other thoughts about this?
This is a feature that is missing in the rpmsg virtio, and perhaps in rpmsg protocol
itself (a ns annoucement ack message or something similar).
A fix for the remoteproc virtio is available here:
https://github.com/arnopo/meta-st-stm32mp-oss/commit/3e57fe73bd19c9bb835ac5a118e50727758b0b96
Don't hesitate to give me feedback on the fix, if you test it.
I added it to my branch and till now I don't see any side effects
I plan to propose the fix after this series.
Thanks,
Arnaud
Cheers,
Philipp
Cheers,
Philipp
[1]:
https://github.com/STMicroelectronics/STM32CubeMP1/blob/master/Projects/STM32MP157C-DK2/Applications/OpenAMP/OpenAMP_raw/Src/openamp.c#L242
[2]:
https://elixir.bootlin.com/linux/v5.17-rc5/source/drivers/rpmsg/virtio_rpmsg_bus.c#L425
[3]:
https://github.com/OpenAMP/open-amp/blob/main/docs/img/coprocessor-rpmsg-ns.png
[4]:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bcabbccabffe7326f046f25737ba1084f463c65c
