The relationship between the three( cpu frequencie,soc_voltage and cpu_voltage) in android 5.1_2.1.0

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The relationship between the three( cpu frequencie,soc_voltage and cpu_voltage) in android 5.1_2.1.0

1,659 Views
yangguang
Contributor II

At different cpu frequencies,the soc_voltage and cpu_voltage will change,freecale board linux kernel will provide the following frequency and voltage control table.

In android 4.3 linux kernel cpu_op-mx6.c,there are the following code:

static struct cpu_op mx6dl_cpu_op_1_2G[] = {

  {

  .pll_rate = 1200000000,

  .cpu_rate = 1200000000,

  .cpu_podf = 0,

  .pu_voltage = 1175000,

  .soc_voltage = 1175000,

  .cpu_voltage = 1275000,},

  {

  .pll_rate = 792000000,

  .cpu_rate = 792000000,

  .cpu_podf = 0,

  .pu_voltage = 1175000,

  .soc_voltage = 1175000,

  .cpu_voltage = 1175000,},

  {

   .pll_rate = 396000000,

   .cpu_rate = 396000000,

   .cpu_podf = 0,

   .pu_voltage = 1175000,

   .soc_voltage = 1175000,

   .cpu_voltage = 1075000,},

};

I understand android 4.3 code,for example,at cpu frequencie 396000000,soc_voltage will be set to 1175000,cpu_voltage will be set to 1075000.

But,

In android 5.1_2.1.0 linux kernel imx6qdl.dtsi,there are the following code:

operating-points = <
/* kHz    uV */
996000  1275000
792000  1175000
396000  1150000
>;
fsl,soc-operating-points = <
/* ARM kHz  SOC-PU uV */
9960001175000
7920001175000
3960001175000
>;

And the above android 4.3 comparison,I can't understand,where is soc_voltage,where is cpu_voltage ,how the table explain

the relationship between the three( cpu frequencie,soc_voltage and cpu_voltage)?

Thanks

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3 Replies

1,415 Views
igorpadykov
NXP Employee
NXP Employee

Hi guang

"operating-points" is for arm core VDD_ARM, fsl,soc-operating-points - for

SOC : VDD_SOC from Table 6. Operating Ranges i.MX6DQ Datasheet

http://cache.freescale.com/files/32bit/doc/data_sheet/IMX6DQCEC.pdf

It may be useful to look at attached Linux Manual Chapter 23

CPU Frequency Scaling (CPUFREQ) Driver, Chapter 24 Dynamic Bus Frequency Driver

Best regards

igor

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1,415 Views
yangguang
Contributor II

Thanks forigorpadykov reply.

As shown below:

operating-points = <
/* kHz    uV */
996000  1275000
792000  1175000
396000  1150000
>;
fsl,soc-operating-points = <
/* ARM kHz  SOC-PU uV */
9960001175000
7920001175000
3960001175000
>;

This table is in andoird 5.1 kernel imx6dl.dts.

My understanding is the "operating-points"  is cpu frequencies and arm core voltage's table.

The "fsl,soc-operating-points" is cpu frequencies and soc voltage's  table.Will this idea right?

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igorpadykov
NXP Employee
NXP Employee

I think you are right

Best regards

igor

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