i.MX ProcessorsのトピックRe: How does the scu interact with m4 or Acore?

How does the scu interact with m4 or Acore?

189659318 — Mon, 24 Feb 2020 08:06:31 GMT

hello,

RT, in the imx8qm, how does the scu interact with m4 or Acore?

In the m4 SDK, it can be seen that m4 communicates with the scu by the following APIs:

1.sc_misc_set_control ();

2.sc_misc_get_control ();

The api1: sc_misc_set_control ();After testing, the communication between m4 and scu can be realized.

Now, I want the scu would reply to m4 when it receives the message from m4. Similar logic has not been found in the SDK....so, I want to ask how does scu send messages to m4 ? Can you provide the demo?

Re: How does the scu interact with m4 or Acore?

igorpadykov — Mon, 24 Feb 2020 10:06:24 GMT

Hi livan

scu interacion is described in sect.2.2 System Controller Linux Manual

included in Linux 4.19.35_1.1.0 Documentation

and in SCFW Porting Kit

Best regards
igor
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Re: How does the scu interact with m4 or Acore?

189659318 — Tue, 25 Feb 2020 14:07:38 GMT

hi,igorpadykov

First of all, thank you for your quick reply!

According to the documentation, the scu interacts with m4 primarily through ipc. In the scfw_api,the communication function is found:

1.ipc_read();

2.ipc_write();

Through these functions, the communication link from m4 to scu can be realized. However, the communication from scu to m4 failed. Can you provide a more detailed example of communication from scu to m4?

BR,

liwan special.

Re: How does the scu interact with m4 or Acore?

bulat_a — Tue, 28 Sep 2021 11:19:48 GMT

Hope it will be useful to you @189659318

"Now, I want the scu would reply to m4 when it receives the message from m4. Similar logic has not been found in the SDK." - Let's consider a FreeRTOS example for M4 cores:

IPC uses MU that is bi-directional connections, thus, the protocol that is used always works as a following:

M4/AP cores : ipc_write(some command)

SCU ipc_handler:

-----SCU ipc_read(cmd) - > perform command

-----SCU ipc_write(result)

M4/Ap core result =ipc_read()

Take a look at

SCU platform/svc/misc/rpc_clnt.c : sc_misc_set_control it calls sc_call_rpc

in SDK nxp

NXP SDK devices/MIMX8QM6/scfw_api/main/ipc_imx8qm.c: sc_call_rpc -

you will see sequential execution of commands:

sc_call_rpc()

....

sc_ipc_write(ipc, msg);

sc_ipc_read(ipc, msg);

Regards,

Bulat