AM5728: dpll params for 1.5Ghz used in Linux

Hi SI,

Just to understand the context, are you trying to boot MPU at 1.5GHz from U-boot itself?

- Keerthy

Yes. you are right. my customer wants to boot MPU at 1.5Ghz to reduce boot time.

And also, I want to check with you if 1.5Ghz was supported in our linux SDK of AM5728 as I questioned in other thread.

I found there were only OPP_NORM and OPP_OD supported in linux.

https://software-dl.ti.com/processor-sdk-linux/esd/docs/06_03_00_106/linux/Foundational_Components/Kernel/Kernel_Drivers/Power_Management.html

But, my customer can work MPU at 1.5Ghz with below. So, I would like to check if this is OK to run MPU at 1.5Ghz.

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

performance

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

1500000

Thanks and Best Regards,

SI.

Hi Keerthy,

Could you please share dpll_param structure for 1.5Ghz operation in U-boot?

Thanks and Best Regards,

SI.

Hi SI,

This is not readily available. I will work on this. Please give me time till early next week.

Best Regards,
Keerthy

Hi Keerthy,

I could not find our recommended PLL settings for 1.5Ghz for U-Boot in the e2e you mentioned. Do you mean they can use the below PLL settings described in the e2e?

Thanks and Best Regards,

SI.

Keerthy,

But, when I checked gel file, I found 20*600/(7+1) = 12000/8 = 1.5Ghz was used as below.

Do you think what is more stable value?  These values are in the gel file included in CCSv9.3.

if(OPP_HIGH == OPP)
{
//1500MHz at 20MHz sys_clk
dpll_m = 600;
dpll_n = 7;
divm2 = 1;
dcc_en = 1;
}

Thanks and Best Regards,

SI.