J5 eco :ARM PLL setting need to change from 600Mhz to 720Mhz in kernel

manju gunnaiah

Hi,

I have modified in uboot to change the ARM_PLL to be 720Mhz in clocks_ti814x.h as below:

#define MODENA_N 0x1
#ifdef CONFIG_TI813X
#define MODENA_M (opp_val_ti813x(0x3C, 0x48))
#else
#define MODENA_M 0x48 //0x3C
#endif
#define MODENA_M2 1
#define MODENA_CLKCTRL 0x1

I confirmed it in uboot that MN2DIV: 0x481C505C (0x481C5000 + 0x48 + 0x14) value is 0x00000048.

But after kernel boots when i verified MN2DIV: 0x481C505C (0x481C5000 + 0x48 + 0x14) value is 0x0000003C.

In kernel again it is set to 600MHz.How can i change in kernel to 720Mhz?

over 9 years ago

0 Pavel Botev over 9 years ago

TI__Guru**** 170625 points

Hi Manju,

I just check this on the TI EVM, the value set in uboot (0x48) is not overwritten in the default kernel, I see it is still 0x48 in the kernel also. Can you check if some part of your own modifications of the linux kernel overwrites this value from 0x48 to 0x3C?

BR
Pavel

0 manju gunnaiah over 9 years ago in reply to Pavel Botev

Expert 1715 points

Dear Pavel,

In kernel we didn't do any modifications with respect to arm_pll.
Where can i find the arm_pll related changes in kernel? so that i can trace.

0 Pavel Botev over 9 years ago in reply to manju gunnaiah

TI__Guru**** 170625 points

Manju,

Refer to the below pointers:

processors.wiki.ti.com/.../TI811X_PSP_User_Guide
processors.wiki.ti.com/.../TI811X_PSP_PM_CLOCK_FRAMEWORK_User_Guide

linux-kernel/arch/arm/plat-omap/cpu-omap.c
linux-kernel/arch/arm/mach-omap2/clkt_clksel.c
linux-kernel/arch/arm/mach-omap2/clock814x_data.c
linux-kernel/arch/arm/mach-omap2/cm81xx.h
linux-kernel/arch/arm/mach-omap2/adpll_ti814x.c

Note that you can change the ARM frequency also from the linux kernel side (not only from uboot), see the wiki page, "Change Clock Rate" section.

BR
Pavel

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J5 eco :ARM PLL setting need to change from 600Mhz to 720Mhz in kernel