Not running at expected frequency or Speed Grade Maintenance not working

[Neeraj Dantu]

Issue: The OSD32MP1 is not running at the expected frequency or is experiencing issues with Speed Grade Maintenance.

Possible Cause: This behavior could be caused by a change in the device tree structure introduced in OpenSTLinux V 2.0 and the fact that the STM32MP1 inside the OSD32MP1 might identify itself as a superset variant to the device that is marked on the package.

Verification: To validate this is the cause of the issue run the following command at the linux prompt

root@osd32mp1-board:~#cpufreq-info

1	root@osd32mp1-board:~#cpufreq-info

If you receive an output like below then this is the cause of the problem.

cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009 Report errors and bugs to cpufreq@vger.kernel.org, please. analyzing CPU 0:   no or unknown cpufreq driver is active on this CPU analyzing CPU 1:   no or unknown cpufreq driver is active on this CPU

1 2 3 4 5 6 7 8 9 10 11 12 13 14

cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009   Report errors and bugs to cpufreq@vger.kernel.org, please.   analyzing CPU 0:     no or unknown cpufreq driver is active on this CPU   analyzing CPU 1:     no or unknown cpufreq driver is active on this CPU

Detailed Explanation of Issue: The CPU’s OPP(Operational Performance Point) table is part of it’s device tree that lets the firmware know what speed grades are available for the device and which hardware variants support the speed grades defined in the OPP table. This information is described in “cpu0_opp_table” node of a device tree. The CPU OPP table for 800MHz speed grade devices is located in stm32mp15xd.dtsi which is included in stm32mp15xf.dtsi and other 800MHz variants’ device tree include files. The CPU OPP table for 650MHz speed grade devices is located in stm32mp15xa.dtsi which is included in stm32mp15xc.dtsi and other 650MHz variants’ device tree include files. The entries in cpu0_opp_table node are tied to the MP1 variants via “opp-supported-hw” property. For example, for 800MHz speed grade parts(STM32MP157F/STM32MP157D), opp-supported-hw is defined as “0x2”. For 650MHz speed grade parts, opp-supported-hw is defined as “0x1”.  Since the OSD32MP1 could use a “0x1” or a “0x2” die to support the 650MHz this can cause issues in speed grade maintenance.

Resolution: Depending on your setup there are multiple ways to resolve this issue. Select the single option below that works best for you:

1. If you are using an Octavo Systems Development Platform then please download the latest images from the respective pages (OSD32MP1-RED, OSD32MP1-BRK)
2. If you are building a custom Debian Image or an OpenSTLinux Image, download the latest versions of the Octavo Systems Debian SDK or the OSD32MP1 Yocto Meta Layer
3. If you would like to update yourself, edit the STM32mp15xa.dtsi file and update the line:
   opp-supported-hw = <0x2>;
   to
   opp-supported-hw = <0x1 0x2>;

• This topic was modified 2 years ago by Greg Sheridan.
• This topic was modified 2 years ago by Greg Sheridan.
• This topic was modified 2 years ago by Greg Sheridan.
• This topic was modified 2 years ago by Greg Sheridan.
• This topic was modified 2 years ago by Greg Sheridan.

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