How to know CPU frequency in keystone - 2

Vijay Gaadhe

Prodigy 240 points

Hi All,

I want to know at which frequency all CPU are running. My processor is 66AK2E02.

CPU frequency support is not available keystone 2 ( In /sys/devices/system/cpu/cpu0/).

I looked into dts file there refclkmain is 100Mhz.

I referred below link

In U-boot command prompt i got below value

-> getclk 0

- clock index [0] - frequency 700000000

-> getclk 1

- clock index [1] - frequency 1000000000

In clock-k2e.h file

enum clk_e {
core_pll_clk,
pass_pll_clk,
ddr3_pll_clk,
sys_clk0_clk,
sys_clk0_1_clk,
sys_clk0_2_clk,
sys_clk0_3_clk,
sys_clk0_4_clk,
sys_clk0_6_clk,
sys_clk0_8_clk,
sys_clk0_12_clk,
sys_clk0_24_clk,
sys_clk1_clk,
sys_clk1_3_clk,
sys_clk1_4_clk,
sys_clk1_6_clk,
sys_clk1_12_clk,
sys_clk2_clk,
sys_clk3_clk
};

In U-boot source code board_k2e.c file

static struct pll_init_data core_pll_config[] = {
{ CORE_PLL, 16, 1, 2 }, /* 800 */
{ CORE_PLL, 17, 1, 2 }, /* 850 */
{ CORE_PLL, 20, 2, 2 }, /* 1000 */
{ CORE_PLL, 25, 1, 2 }, /* 1250 */
{ CORE_PLL, 27, 1, 2 }, /* 1350 */
{ CORE_PLL, 28, 2, 2 }, /* 1400 */
{ CORE_PLL, 30, 1, 2 }, /* 1500 */
};

static struct pll_init_data pa_pll_config =
{ PASS_PLL, 20, 1, 2 }; /* 1000 */

#ifdef CONFIG_SPL_BOARD_INIT
static struct pll_init_data spl_pll_config[] = {
{ CORE_PLL, 16, 1, 2 },
};

So how can i know at which frequency my all CPU are running ????

Thanking in advance,

Vijaykumar

over 9 years ago

0 Yordan Kovachev over 9 years ago

TI__Guru**** 161600 points

Hi,

From user space, you can use:
cat /sys/devices/system/cpu/cpuX/cpufreq/scaling_cur_freq

Where cpuX is the CPU you need to monitor.

In order to see the set of frequencies you can change, exececute:
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies

To change the frequency, you first need to change the governor:
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
ondemand userspace performance conservative powersave
Change it to userspace:
echo userspace > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

Then set the needed cpu speed from the scaling_available_frequencies, i.e.:
echo 500000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed
Now the CPU frequency should be changed to 500MHz, you can verify it with:
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq

Best Regards,
Yordan

0 Raja over 9 years ago

TI__Guru* 81335 points

Hi Vijaykumar,

Are you working on EVM or Custom board? I think you can see the frequency in the u-boot log itself and all the ARM cores will run at the same frequency.

Refer below instructions to get and set the frequency.

Thank you.

0 Vijay Gaadhe over 9 years ago in reply to Yordan Kovachev

Prodigy 240 points

Yordan,
Thanks for quick reply.

As I told CPU frequency is not available in keystone 2 . That means /sys/devices/system/cpu/cpu0/cpufreq Folder is not available so i can not do whatever operation you mention from user space.

Any other way ??? or how to enable above support ??????

Thanks,
Vijaykumar

0 Titusrathinaraj Stalin over 9 years ago

TI__Guru** 116100 points

Keystone2 devices doesn't support CPU frequency (CPU Idle/Freq governors) scaling driver.
You can change the CPU clock via u-boot, I hope linux kernel won't modify the CPU clock unless you modify the clock in driver.

0 Vijay Gaadhe over 9 years ago in reply to Titusrathinaraj Stalin

Prodigy 240 points

Hi Titus,
Thanks for confirmation of Keystone2 devices doesn't support CPU frequency (CPU Idle/Freq governors) scaling driver.

U-boot is giving core PLL clock and pass PLL clock . Which clock i can use ?

In below equation which value i have to use ?

Here the calculation example assuming the refclkmain is 125MHz please use the refclkmain value mentioned above when changing on EVM):

125000000*19/(1*2) = 1187500000 Hz

Thanks,
Vijaykumar

0 Titusrathinaraj Stalin over 9 years ago in reply to Vijay Gaadhe

TI__Guru** 116100 points

You can change the Tetris (ARM) clock using "pllset" command.

u-boot# getclk 2
u-boot# pllset arm 19 1 2
u-boot# getclk 2

Calc:
125000000*19/(1*2) = 1187500000 Hz (~1.2GHz)

Refer to this wiki page.
processors.wiki.ti.com/.../MCSDK_UG_Chapter_Exploring

0 Vijay Gaadhe over 9 years ago in reply to Titusrathinaraj Stalin

Prodigy 240 points

Hi Titus,
Thanks for reply.

I don't want to change frequency. I want get existing frequency.
In getclk command which index(0,1,2) i can use ?
After getclk command which pll multiplier and pre divider i have to use so i can get correct frequency ?

Thanks,
Vijaykumar

0 Titusrathinaraj Stalin over 9 years ago in reply to Vijay Gaadhe

TI__Guru** 116100 points

"getclk 2" is the command to get the ARM clock (Tetris)

u-boot# getclk 2

I did it and got the "1200000000" Hz in u-boot.

0 Vijay Gaadhe over 9 years ago in reply to Titusrathinaraj Stalin

Prodigy 240 points

Titus,

But getclk 2 command take index from enum clk_e from k2e-clock.h file.

enum clk_e {
core_pll_clk,
pass_pll_clk,
ddr3_pll_clk,
sys_clk0_clk,
sys_clk0_1_clk,

u-boot# getclk 2

I am getting 400000000.

My all 4 CPU running at 400Mhz.
so this is right or wrong ??

Big Thanks for quick reply.
Vijaykumar

0 Titusrathinaraj Stalin over 9 years ago in reply to Vijay Gaadhe

TI__Guru** 116100 points

Okay, I got it.
I tested this in K2H board but you are using K2E board right.
What package are you using and version please ?
MCSDK or Processor SDK ?

It seems "getclk 2" means DDR3 clock.
Can you please try "getclk 3" and "getclk 4" ?

0 Vijay Gaadhe over 9 years ago in reply to Titusrathinaraj Stalin

Prodigy 240 points

Hi Titus,

I am using linux kernel 3.10.61 and related U-boot source code.
u-boot# getclk 3
700000000
u-boot# getclk 4
700000000

can you tell me in K2H board at index 2 what is present ?
so i can find in my U-boot source code.

Thanks,
Vijaykumar

0 Titusrathinaraj Stalin over 9 years ago in reply to Vijay Gaadhe

TI__Guru** 116100 points

In K2H latest processor SDK package, getclk 2 is mentioned as "Tetris clock"

I just checked the KS2 PLL calculator for K2H and K2E, it has some difference in clock structure, in K2E, ARM PLL is not available but K2H.
I'm checking with HW experts which SYSCLK is used for ARM clock in K2E, so that you can read the correct enum value to get the ARM clock.

Also you need to check the "pll_type_e" enum structure to get the clock not "clk_e" structure.

Compare the both "pll_type_e" structure of K2H and K2E, you could see TETRIS_PLL for K2H but not for K2E.
I think, we need to read "CORE_PLL" to get the ARM clock in K2E.

Please let me know if any issue in understanding.

PS: PLL enum definitions are changed in latest processor SDK

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How to know CPU frequency in keystone - 2