cpu_is_xxx for AM3715 on linux?

Ben Henricksen

Other Parts Discussed in Thread: AM3715

What cpu type should the AM3715 report in a Linux build? Currently our system based on the AM3730 thinks it is a cpu_is_3630.

The board is running at 600 Mhz rather than the possible 1 GHz. What test would be failing here? Target VDD1_OPP4 and VDD2_OPP2 is on the bootup screen output.

over 13 years ago

0 Anil over 13 years ago

TI__Expert 6655 points

Hi Ben,

I think mostly AM3715 is also fall under cpu_is_omap3630().

By default kernel is boots-up with default MPU frequency as 600MHz. After kernel boots up we can change the frequency using cpufreq framework, details can be found at

http://processors.wiki.ti.com/index.php/UserGuidePowerMgmt_PSP_04.02.00.07#cpufreq_.26_SmartReflex

Regards

AnilKumar

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0 Ben Henricksen over 13 years ago in reply to Anil

Intellectual 855 points

Thanks for the info.

We've set up menuconfig as directed with CPU Frequency scaling but still can't get it to go over 600MHz, or lower.

The cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies

reported 1000000 800000 600000 300000 but we can't seem to select anything different.

Regards,

Ben

0 Anil over 13 years ago in reply to Ben Henricksen

TI__Expert 6655 points

Hi Ben,

You can get these details from Kernel documentation "<kernel>/Documentation/cpu-freq/governors.txt"

To list all available governors:

   cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors

To see current active governor

   cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

To switch to a different governor

    echo -n "<governor_name>" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

switch to 'userspace' governor

    echo -n "userspace" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

switch to 1GHz

    echo 1000000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

Regards

AnilKumar

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0 Ben Henricksen over 13 years ago in reply to Anil

Intellectual 855 points

The menuconfig instructions from here sorted it out.

http://e2e.ti.com/support/dsp/omap_applications_processors/f/447/p/40504/141404.aspx#141404

The SRF setting in particular.

The

echo 1000000 > /sys....../scaling_setspeed then worked. It would run before with no error, but the file would be unchanged.

Thanks.

0 Anil over 13 years ago in reply to Ben Henricksen

TI__Expert 6655 points

Hi Ben,

Refer this wiki page (User guide for AM335x device), only look at the kernel configuration and usage not more than that.

http://processors.wiki.ti.com/index.php/AM335x_Power_Management_User_guide#cpufreq

Regards

AnilKumar

Please mark this Forum post as answered via the Verify Answer button below if it helps answer your question. Thanks!

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cpu_is_xxx for AM3715 on linux?