AM5708: smartreflex not being used

reyaz ali

Part Number: AM5708

We are currently measuring power consumption for AM5708 and found out that in the Linux kernel SDK smartreflex code is not getting compiled even though AVS(Adaptive Voltage Scaling) is enabled in .config .

Does AM5708 have some other implementation of AVS?.

over 5 years ago

0 Karthik Ramanan over 5 years ago

TI__Guru** 113810 points

Hi Reyaz,

Few questions:

Can you please provide the exact config that you are looking at to determine the AVS is enabled or not?
Also, which version of the SDK are you using?
Can you check whether this config is enabled by checking the kernel configs enabled on the running target?

Regards

Karthik

0 reyaz ali over 5 years ago in reply to Karthik Ramanan

Prodigy 20 points

Hi Karthik,

Can you please provide the exact config that you are looking at to determine the AVS is enabled or not?

I have CONFIG_POWER_AVS=y in my .config file

Also, which version of the SDK are you using?

I am using 'ti-processor-sdk-linux-am57xx-evm-05.03.00.07'

Can you check whether this config is enabled by checking the kernel configs enabled on the running target?

As answered in the first query it is enabled.

Also can you point us to AVS software related implementation documentation for AM5708?

Thanks,

Reyaz

0 Keerthy J over 5 years ago in reply to reyaz ali

TI__Guru**** 163490 points

HHi Reyaz,

CONFIG_POWER_AVS is not the way smartreflex is enabled on am5708.

The am5708 supports AVS class 0 which is static. Where in the smartreflex compensated
voltage values for each OPP(voltage/Frequency pair) is blown into the efuse and not computed
dynamically. As and when the OPP is changed the smartreflex compensated voltage value is read
from the efuse registers and PMIC is programmed accordingly.

code: drivers/opp/ti-opp-supply.c

function: _store_optimized_voltages

ti,efuse-settings property is checked in Device tree:

ex:                 opp_supply_mpu: opp-supply@4a003b20 {
                        compatible = "ti,omap5-opp-supply";
                        reg = <0x4a003b20 0xc>;
                        ti,efuse-settings = <
                        /* uV   offset */
                        1060000 0x0
                        1160000 0x4
                        1210000 0x8
                        >;
                        ti,absolute-max-voltage-uv = <1500000>;
                };

every OPP voltage value has some efuse offset which has the smartreflex compensated voltage value.

Config option: CONFIG_ARM_TI_CPUFREQ

If this answers your question please resolve the thread.

Best Regards,
Keerthy

0 VSS over 5 years ago in reply to Keerthy J

Prodigy 160 points

Keerthy,

If AM5708 supports only Class 0 (static) voltage scaling on the boot-up, how do we account for die temperature changes & loading? In our system, we see that AM5708's junction temperature is quite high when running Dhrystone benchmark application compared to TI's published numbers for the same application. This is with a 25mm x 25mm heatsink at room temeperature.

We would be interested to know the technique (heat sink used) employed to achieve the low temperature numbers published "spracg1" application note.

Thanks.

0 Keerthy J over 5 years ago in reply to VSS

TI__Guru**** 163490 points

Hi Vijay,

As mentioned earlier our smartreflex solution is static. No compensation is achieved with
varying temperatures. Every OPP has a fixed compensated value blown in the Efuse.

I will get back to you with details on the heat sync employed in a couple of days.

Best Regards,
Keerthy

0 Keerthy J over 5 years ago in reply to Keerthy J

TI__Guru**** 163490 points

Hi Vijay,

The part number is:

CTS BDN10-3CB/A01

https://www.digikey.com/product-detail/en/cts-thermal-management-products/BDN10-3CB-A01/294-1098-ND/272736

Please resolve the query if you do not have any other questions related to topic.

Best Regards,
Keerthy

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AM5708: smartreflex not being used