SK-AM64: Periphery Reset Signals

Walter Stoll

Part Number: SK-AM64

Hi Team,

we are developping a new custom board based on the AM64x CPU. When looking at the SK-AM64 schematics for TI implementation ideas, we noticed that certain periphery components are supplied with a dedicated reset signal:

CPSW_RGMII1_RESETn: Dedicated reset for PHY 1

CPSW_RGMII2_RESETn: Dedicated reset for PHY 1

OSPI_RSTn: Dedicated reset for OSPI NOR-Flash

The reset signals above can be activated by one GPIO each. We guess that the goal behind this implementation is to provide a possibility to recover these components from hardware dead-locks. However, we think this would require some driver support to work properly.

Is there any driver support that manages the reset signals or is it up to a userspace application to handle them ?

What is the idea behind this dedicated reset signal concept ?

over 4 years ago

+1 Andrei Aldea over 4 years ago

TI__Expert 3340 points

Hi Walter,

You are correct, the intent behind the individual reset pins for the different interfaces is to allow a user to reset a hung-connection without affecting other transactions that might be going on in the system. I do believe this would require user space intervention though and would be application specific.

I don't believe this is natively supported in-driver but I will refer one of my software colleagues for that.

Best,

Andrei

0 Schuyler Patton over 4 years ago in reply to Andrei Aldea

TI__Mastermind 41240 points

Hi,

Depending on the OS used there could an option to let the respective MDIO driver handle the reset. With Linux the mdio driver has an option to define a reset based on a gpio. Here is an example from the Linux device tree binding document for mdio. Please note this is just one example.

Best Regards,

Schuyler

0 Walter Stoll over 4 years ago in reply to Schuyler Patton

Intellectual 490 points

Perfect, thaks a lot

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SK-AM64: Periphery Reset Signals