Reset Manager Driver for Hard Processor System¶
Last updated: May 06, 2026
Upstream Status: Not Upstreamed
Devices supported: Agilex™ 3, Agilex™ 5, Agilex™ 7
Introduction¶
The reset manager generates module reset signals based on reset requests from various sources in the HPS, and performs software writing to the module-reset control registers.
The HPS contains multiple reset domains. Each reset domain can be reset independently. A reset can be initiated externally, internally, or through software. For more information about the reset manager, please refer to:
- Agilex™ 3: Altera® Agilex™ 3 Hard Processor System Technical Reference Manual.
- Agilex™ 5: Altera® Agilex™ 5 Hard Processor System Technical Reference Manual.
- Agilex™ 7: Altera® Agilex™ 7 Hard Processor System Technical Reference Manual.
Driver Sources¶
The source code for this driver can be found at:
Driver Capabilities¶
- Manage the system level reset.
- Support Assert and De-assert of the reset signal.
- Monitor the status of the reset signal.
For reset manager capabilities in different devices, please refer to Differences Among Altera® SoC Device Families
Kernel Configurations¶
CONFIG_RESET_SIMPLE
Device Tree¶
Example Device tree location for reset signal parameter for Agilex™ 5 device:
rst: rstmgr@10d11000 {
compatible = "altr,stratix10-rst-mgr", "altr,rst-mgr";
reg = <0x10d11000 0x1000>;
#reset-cells = <1>;
};
Also dt-bindings can be found at:
Test Procedures¶
You can apply a cold or warm reset from U-Boot and Linux shell commands as follow:
- U-Boot: The reset is applied using the reset command from the U-Boot shell. The type of reset is specified either with a environment variable or through a parameter in the reset command. This varies depending on the U-Boot branch and the SoC device. The default is cold reset if the environment variable is not assigned nor a parameter is passed to the reset command.
- Linux: The reset is applied using the reboot command from the Linux shell. The type of reset depends on the value assigned to the reboot kernel command line parameter passed to Linux. The default is cold reset if the parameter is not defined in the kernel command line.
The following table summarizes the procedure to apply a software (from U-Boot or Linux) Warm or Cold reset and the different variations of this.
| Device | Cold Reset | Warm Reset |
|---|---|---|
| Agilex™ 5 Agilex™ 3 |
======= U-Boot ======= Before 2025.07 branch: reset env variable undefined U-Boot shell: # reset 2025.07 branch or later(reset env variable NOT used): U-Boot shell: # reset ======= Linux ======= Kernel Command line: reboot parameter undefined. Linux shell: $ reboot |
======= U-Boot ======= Before 2025.07 branch: reset env variable set to warm U-Boot shell: # setenv reset warm # reset 2025.07 branch or later(reset env variable NOT used): U-Boot shell: # reset -w ======= Linux: ======= Kernel Command line: reboot=warm Linux shell: $ reboot |
| Agilex™ 7 | ======= U-Boot ======= Before 2025.10 branch: reset env variable undefined U-Boot shell: # reset 2025.10 branch or later(reset env variable NOT used): U-Boot shell: # reset ======= Linux: ======= Kernel Command line: reboot parameter undefined. Linux shell: $ reboot |
======= U-Boot ======= Before 2025.10 branch: reset env variable set to warm U-Boot shell: # setenv reset warm # reset 2025.10 branch or later(reset env variable NOT used): U-Boot shell: # reset -w ======= Linux: ======= Kernel Command line: reboot=warm Linux shell: $ reboot |
The following table shows the software flow when the SW (U-Boot or Linux) requests a Warm or Cold reset.
| Device | Cold Reset | Warm Reset |
|---|---|---|
| Agilex™ 5 Agilex™ 3 |
1) SW performs a SMC call to ATF. 2) SMC handler in ATF sends a reset request to SDM using SDM mailbox. |
1) SW performs a SMC call to ATF. 2) SMC handler in ATF sends a reset request to SDM using SDM mailbox. |
| Agilex™ 7 | 1) SW performs a SMC call to ATF. 2) SMC handler in ATF sends a reset request to SDM using SDM mailbox. |
1) SW performs a SMC call to ATF. 2) SMC handler applies the reset through the Reset Manager. |
Known Issues¶
None Known
Notices & Disclaimers¶
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Created: May 25, 2024