Linux/AM3351: Wakeup from DMTimer 1ms

Manoj Kumar

Part Number: AM3351
Other Parts Discussed in Thread: CCSTUDIO

Tool/software: Linux

I'm working on AM3351 based customised board. In AM335x TRM section 8.1.4.5 says that below events can be wakeup processor from Deepsleep mode.

• GPIO0 bank
• dmtimer1_1ms (timer based wakeup)
• USB2PHY (USB resume signaling from suspend) – Both USB ports supported.
• TSC (touch screen controller, ADC monitor functions )
• UART0 (Infra-red support)
• I2C0
• RTC alarm

But I'm not finding any reference on how to implement the Dmtimer1_1ms based deepsleep wakeup mode.

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

The PM experts have been notified. They will respond here.

Please post what Linux version you use.

0 Manoj Kumar over 8 years ago in reply to Biser Gatchev-XID

Intellectual 900 points

Thanks Biser,
I'm using Linux version 4.1.18.

0 Pavel Botev over 8 years ago

TI__Guru**** 170625 points

Hi Manoj,

In PSDK 3.03 (linux kernel 4.4) by default we have only these wake-up sources for DeepSleep0 (mem) power state:

UART0
GPIO0
Touchscreen

I found we have dmtimer1_1ms wake-up mode implemented in AM335x StarterWare, so you can get that source code as reference.

processors.wiki.ti.com/.../AM335x_StarterWare_Power_management

Regards,
Pavel

0 Pavel Botev over 8 years ago in reply to Pavel Botev

TI__Guru**** 170625 points

Manoj,

We have also example of DMTIMER7 usage as wake-up source from standby mode, you can also take that code as a reference:

processors.wiki.ti.com/.../AM335x_Power_Management_Standby_User's_Guide

Note that DMTIMER1_1ms is described in below DTS file and can be accessed from below drivers:

linux-4.4.41/arch/arm/boot/dts/am33xx.dtsi

timer1: timer@44e31000 {
compatible = "ti,am335x-timer-1ms";
reg = <0x44e31000 0x400>;
interrupts = <67>;
ti,hwmods = "timer1";
ti,timer-alwon;
};

linux-4.4.41/arch/arm/mach-omap2/timer.c
linux-4.4.41/arch/arm/plat-omap/dmtimer.c

Regards,
Pavel

0 Manoj Kumar over 8 years ago in reply to Pavel Botev

Intellectual 900 points

Hi Pavel,

we need Dmtimer1_1ms as wakeup source for Deepsleep mode not for standby mode. Can you share the link for StarterWare source code for power management.

We are using AM3351 processor. Is it possible to implement starterware code in Linux userspace..?

Regards,
Manoj

0 Pavel Botev over 8 years ago in reply to Manoj Kumar

TI__Guru**** 170625 points

Manoj,

Manoj Kumar said:
we need Dmtimer1_1ms as wakeup source for Deepsleep mode not for standby mode.

I know that. But I was not able to find any linux reference code closer than that (DMTIMER7 wake up from standby).

Manoj Kumar said:
Can you share the link for StarterWare source code for power management.

I am not familiar with StarterWare. You should ask/post in StarterWare forum:

Manoj Kumar said:
We are using AM3351 processor. Is it possible to implement starterware code in Linux userspace..?

I am not familiar with StarterWare. From what I know it is bare metal programming, similar to CCStudio GEL files. I think you can not just copy paste StarterWare code to Linux userspace. You should explore the StarterWare DMTIMER1 programming sequence and registers settings and apply these in linux, but this can not be done with simple copy-paste transfer.

Regards,
Pavel

0 Manoj Kumar over 8 years ago in reply to Pavel Botev

Intellectual 900 points

Hi Pavel,

Can you check with your software team on how to implement dmtimer based deep sleep wakeup mode. Since it is mentioned in the TRM, it is achievable or is there any limitations which prevents configuring dmtimer as deepsleep wakeup source.

Regards,
Manoj

0 Pavel Botev over 8 years ago in reply to Manoj Kumar

TI__Guru**** 170625 points

Manoj Kumar said:
Can you check with your software team on how to implement dmtimer based deep sleep wakeup mode.

For how to implement dmtimer wake up, refer to the AM335x TRM, sections:

8.1.6.13 Timer Clock Structure
20.2 DMTimer 1ms

Manoj Kumar said:
Since it is mentioned in the TRM

It is not just mentioned. It is fully documented and explained.

Manoj Kumar said:
it is achievable or is there any limitations which prevents configuring dmtimer as deepsleep wakeup source.

Yes, it is achievable. I do not find any limitation. Just one common limitation for all timers described in AM335x Silicon Errata, advisory 1.0.39, which has its workaround described.

Regards,
Pavel

0 Pavel Botev over 8 years ago in reply to Pavel Botev

TI__Guru**** 170625 points

Manoj,

You can also refer below links for reference:

processors.wiki.ti.com/.../TI81xx_PSP_Porting_Guide

processors.wiki.ti.com/.../AM335x_Power_Management_Standby_User's_Guide - profiling is done using timer1, see Add-timer-profiling-support.zip

Regards,
Pavel

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Linux/AM3351: Wakeup from DMTimer 1ms