AM623: How to control LPSC_GPMC

Koichiro Tashiro

Part Number: AM623

Tool/software:

Hi,

My customer wants to use GPMC.
According to Clock Tree tool, FCLK to GPMC is disabled by default and LPSC_GPMC needs to be enabled to provide FCLK to GPMC.
But it is not clear how to configure LPSC_GPMC.
It seems LPSC_GPMC is mapped at Index 15 of GP_Core_CTL power domain in PSC_0 according to TRM table 6-3, but there is no register or programming information available.

Thanks and regards,
Koichiro Tashiro

2 months ago

0 Swargam Anil 2 months ago

TI__Mastermind 46626 points

Hello Koichiro Tashiro,

Please let me know why customer want to disable the LPSC ? What is the customer use case ?

The above requirement (Disable the GPMC LPSC) want to be done on which core (Linux A53 core or DM R5F core)?

Regards,

Anil.

0 Koichiro Tashiro 2 months ago in reply to Swargam Anil

TI__Mastermind 22935 points

Hi Anil,

Swargam Anil said:
Please let me know why customer want to disable the LPSC ? What is the customer use case ?

No. The customer wants to enable the LPSC to use GPMC. It is disabled by default.

Swargam Anil said:
The above requirement (Disable the GPMC LPSC) want to be done on which core (Linux A53 core or DM R5F core)?

I will check on it.

Thanks and regards,
Koichiro Tashiro

0 Swargam Anil 2 months ago in reply to Koichiro Tashiro

TI__Mastermind 46626 points

Hello Koichiro Tashiro,

In the DM R5F application, the generated code for the GPMC will take the core of the LPSC module to be ON before the clock enablement of the GPMC.

Again, users don't need to control the LPSC module ON or OFF.

Regards,

Anil.

0 Koichiro Tashiro 2 months ago in reply to Swargam Anil

TI__Mastermind 22935 points

Hi Anil,

Swargam Anil said:
The above requirement (Disable the GPMC LPSC) want to be done on which core (Linux A53 core or DM R5F core)?

The customer wants to enable from Linux A53 core.

Koichiro Tashiro said:
Again, users don't need to control the LPSC module ON or OFF.

Do you mean LPSC module is automatically controlled? If so, who is enabling it and how?

Thanks and regards,
Koichiro Tashiro

0 Swargam Anil 1 month ago in reply to Koichiro Tashiro

TI__Mastermind 46626 points

Hello Koichiro Tashiro,

Typically, the LPSC bit controlling should be done through the TISCI call and the TISCI call goes to DM (Device Management) and the DM core can control the LPSC bit.

I am routing your query to a Linux expert to comment on the Linux core.

Regards,

Anil.

0 Hong Guan64 1 month ago in reply to Swargam Anil

TI__Guru 68540 points

Hi Koichiro,
For u-boot/Linux, the gpmc dt node is used to instantiate the LPSC_GPMC, here is gpmc0 dt node for AM62x
https://git.ti.com/cgit/ti-u-boot/ti-u-boot/tree/arch/arm/dts/k3-am62-main.dtsi?h=10.01.10#n864

This is an early e2e on configuring LPSC_GPMC directly via MMRs on AM64x for your reference.
RE: AM6442: Crash in uboot when trying to read or write memory zone
Best,
-Hong

0 Koichiro Tashiro 1 month ago in reply to Hong Guan64

TI__Mastermind 22935 points

Hi Hong,

Is it possible to enable/disable GPMC_FCLK manually?
Or it must be done via TISCI call to DM? If so, how Linux application send TISCI call to DM?

Thanks and regards,
Koichiro Tashiro

0 Hong Guan64 1 month ago in reply to Koichiro Tashiro

TI__Guru 68540 points

Koichiro Tashiro said:
Is it possible to enable/disable GPMC_FCLK manually?

Yes, it is possible to configure LPSC MMRs to power on GPMC block. The referenced e2e in my last reply listed the steps to directly configure LPSC MMRs for GPMC block on AM64x. The same steps is applicable to AM62x.

Koichiro Tashiro said:
Or it must be done via TISCI call to DM? If so, how Linux application send TISCI call to DM?

In Linux SDK, clock/power management flow is like: DTS node -> clk/power driver -> LPSC clk/power configuration directly or via DM.
Best,
-Hong

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AM623: How to control LPSC_GPMC