AM4376: How to use MPU_RAM by CPDMA

UNA

Part Number: AM4376

Hi,

I posted in the following thread about the internal memory settings for the receive descriptor and received a comment that it can be used if it is 0x402F_0400 - 0x402F_FFFF.
However, My customer says that the 0x402F_0400 - 0x402F_FFFF region will not write any incoming data at all. This area is not used by the OS.
The 0x4030_0000 in the OCMCRAM region is not a problem.

Do We need to do any special configuration to use MPU_RAM(0x402F_0400 - 0x402F_FFFF)?

Best Regards,
H.U

over 5 years ago

0 Schuyler Patton over 5 years ago

TI__Mastermind 40310 points

Hi,

I will have to discuss internally with teams. Is the 4030_0000 region working when both rx descriptors and buffers are located here?

Best Regards,

Schuyler

0 UNA over 5 years ago in reply to Schuyler Patton

Mastermind 7980 points

Hi Schuyler,

When running in the 4030_0000 region, the receive descriptors are set to CPSW_CPPI_RAM and the receive buffers are set to OCMCRAM.
The receive descriptors have been successfully updated.

Best Regards,
H.U

0 UNA over 5 years ago in reply to Schuyler Patton

Mastermind 7980 points

Hi Schuyler,

I would be grateful if you could let me have your answer concerning this matter.

Best Regards,
H.U

0 Nick Saulnier over 4 years ago in reply to UNA

TI__Guru** 102510 points

Hello H.U,

We apologize the delayed response. I will have a reply with more information soon.

Regards,

Nick

0 UNA over 4 years ago in reply to Nick Saulnier

Mastermind 7980 points

Hi Nick,

I’m sorry to rush you, but my customer are waiting for your reply.

Best Regards,
UNA

0 UNA over 4 years ago in reply to Nick Saulnier

Mastermind 7980 points

Hi Nick,

I have asked several questions about CPSW, including another thread.
However, solving the problems in this thread is a high priority for our customer, I would appreciate it if you could focus on this one.

Best Regards,
UNA

0 Schuyler Patton over 4 years ago in reply to UNA

TI__Mastermind 40310 points

Hi,

After researching the AM437x TRM a little further the MPU_RAM will not be useable as a destination for CPSW packets via the CPDMA. The MPU_RAM is in inside the MPU subsystem, this module is considered an initiator port and so is the CPSW CPDMA module. The OCMC RAM is a target port.

Please refer to sections 4.1.2.2 L3 Port Mapping for descriptions of initiator and target ports and section 3.1 Introduction for the ARM MPU Subsystem that describes the MPU RAM module for more information.

Best Regards,

Schuyler

0 UNA over 4 years ago in reply to Schuyler Patton

Mastermind 7980 points

Hi Schuyler,

Thank you for your reply.
I understood that CPDMA cannot use MPU_RAM. In the same way, does that mean EDMA can't use MPU_RAM either?

Best Regards,
UNA

0 Schuyler Patton over 4 years ago in reply to UNA

TI__Mastermind 40310 points

Hi,

That is correct, the MPU_RAM in the MPU Subsystem is not a target port for any L3 interconnect initiators.

Best Regards,

Schuyler

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AM4376: How to use MPU_RAM by CPDMA