Table of Contents

Prerequisites

1. You have installed Petalinux 2018.1 (or later).
2. You have created a Petalinux project using the BSP for your board.
3. You were able to boot the pre-built images on your board.
4. You have a stand-alone application running on the RPU that supports power management using the XilPM library. If not, see Minimal RPU Applications on how to run a minimal application on the RPU.
5. The overviw of EEMI APIs described in https://www.xilinx.com/support/documentation/user_guides/ug1199-zynq-power-management.pdf

Out-of-box PM Demo

• Boot the PetaLinux pre-built image on the board.
• Log in on the Linux console, type: "hellopm"

Runtime PM

• "Devices may be put into low-power states while the system is running, independently of other power management activity in principle. However, devices are not generally independent of each other (for example, a parent device cannot be suspended unless all of its child devices have been suspended)."

CPU PM

CPU Hotplug

• Kernel Features
  • [*] Support for hot-pluggable CPUs
• Power management options
  • [*] Suspend to RAM and standby

$ echo 0 > /sys/devices/system/cpu/cpu3/online

CPU Idle

• CPU Power Management
  • CPU Frequency scaling
    • [*] CPU Frequency scaling
      • Default CPUFreq governor
        • Userspace
      • <*> Generic DT based cpufreq driver

$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq

$ cat /sys/devices/system/cpu/cpu1/cpufreq/scaling_available_governors

$ echo userspace > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

$ cat /sys/devices/system/cpu/cpu1/cpufreq/scaling_available_frequencies
 

$ echo <frequency> > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

System PM

Suspend

• Power management options
  • [*] Suspend to RAM and standby
  • [*] User space wakeup sources interface
  • [*] Device power management core functionality

• Device Drivers
  • SOC (System On Chip) specific Drivers
    • XIlinx SoC drivers
      • Zynq MPSoC SoC
        • [*] Enable Xilinx Zynq MPSoC Power Management Driver
        • [*] Enable Zynq MPSoC generic PM domains
• Firmware Drivers
  • Zynq MPSoC Firmware Drivers
    • -*- Enable Xilinx Zynq MPSoC firmware interface

$ echo mem > /sys/power/state

Wake-up Source

UART

Get API Version

$ echo pm_get_api_version > (sysfs node)

Request Suspend

$ echo pm_request_suspend <node> > (sysfs node)

Self Suspend

$ echo pm_self_suspend <node> > (sysfs node)

Force Power Down

$ echo pm_force_powerdown <node> > (sysfs node)

Abort Suspend

$ echo pm_abort_suspend > (sysfs node)

Request Wake-up

$ echo pm_request_wakeup <node> <set_address> <address> > (sysfs node)

Set Wake-up Source

$ echo pm_set_wakeup_source <target> <wkup_node> <enable> > (sysfs node)

System Shutdown

$ echo pm_system_shutdown <action> <scope> > (sysfs node)

• 0: Shutdown
• 1: Reset
• 2: Set reset scope

• 0: APU
• 1: PS
• 2: System

Request Node

$ echo pm_request_node <node> > (sysfs node)

Release Node

$ echo pm_release_node <node> > (sysfs node)

Set Requirement

$ echo pm_set_requirement <node> <capabilities> > (sysfs node)

Set Max Latency

$ echo pm_set_max_latency <node> <latency> > (sysfs node)

Get Node Status

$ echo pm_get_node_status <node> > (sysfs node)

• Status: Node power status (see below.)
• Usage: The master(s) using this node (bit-map):
  • Bit 0: Used by this master
  • Bit 1: Used by other master(s)
• Requirement: Capabilities required (bit-map):
  • Bit 0: Accessible.
  • Bit 1: Retain context.
  • Bit 2: Wake-up source.

Get Operating Characteristic

$ echo pm_get_operating_characteristic <node> > (sysfs node)

Reset Assert

To perform assert, release or pulse reset on specific reset line.

$ echo pm_reset_assert <reset> <action> > (sysfs node)

Reset Get Status

To get the status of specific reset line.

$ echo pm_reset_get_status <reset> > (sysfs node)

MMIO Read

To read a value from an address that is not directly accessible from Linux/APU.

$ echo mmio_read <address> > (sysfs node)

MMIO Write

To write a value to a specific address that is not directly accessible from Linux/APU.

$ echo mmio_write <mask> <address> <value> > (sysfs node)

Get Chip ID

$ echo pm_get_chipid > (sysfs node)

Get pin control functions

$ echo pm_pinctrl_get_function <pin-number> > (sysfs node)

Set pin control functions

$ echo pm_pinctrl_set_function <pin-number> <function-id> > (sysfs node)

Get configuration parameters for the pin

$ echo pm_pinctrl_config_param_get <pin-number> <parameter to get> > (sysfs node)

Set configuration parameters for the pin

$ echo pm_pinctrl_config_param_set <pin-number> <parameter to set> <param value> > (sysfs node)

Control device and configurations

$ echo pm_ioctl <node id> <ioctl id> <arg1> <arg2> > (sysfs node)

Query Data

$ echo pm_query_data <query id> <arg1> <arg2> <arg3> > (sysfs node)

Enable Clock

$ echo pm_clock_enable <clock id> > (sysfs node)

Disable Clock

$ echo pm_clock_disable <clock id> > (sysfs node)

Get Clock State

$ echo pm_clock_getstate <clock id> > (sysfs node)
$ cat(sysfs node)

Set Clock Divider

$ echo pm_clock_setdivider <clock id> <divider value> > (sysfs node)

Get Clock Divider

$ echo pm_clock_getdivider <clock id> > (sysfs node)

Set Clock Rate

$ echo pm_clock_setrate <clock id> <clock rate> > (sysfs node)

Get Clock Rate

$ echo pm_clock_getrate <clock id> > (sysfs node)

Set Clock Parent

$ echo pm_clock_setparent <clock id> <parent clock id> > (sysfs node)

Get Clock Parent

$ echo pm_clock_getparent <clock id> > (sysfs node)

CSU/PMU Register Access 

Read/Write the CSU and PMU global registers.

Register Write :

$ echo  <address> <mask> <value> > /sys/firmware/zynqmp/config_reg

Register Read :

$ echo <address> > /sys/firmware/zynqmp/config_reg
$ cat /sys/firmware/zynqmp/config_reg

CSU and PMU global registers are classified to two lists. White list (accessed all the time by default), Black list (accessed when a compile time flag is set)

we have a #define option (SECURE_ACCESS_VAL) that provides access to black list. To Access black list registers build the PMUFW with  SECURE_ACCESS_VAL flag set.

White List Registers :

CSU Module :

• Csu_status
• Csu_multi_boot
• Csu_tamper_trig
• Csu_ft_status
• Jtag_chain_status
• Idcode
• Version
• Csu_rom_digest(0:11)
• Aes_status
• Pcap_status

PMU Global Module :

• Global_control
• Global_Gen_Storage0 - 6
• Pers_Glob_Gen_Storage0-6
• Req_Iso_Status
• Req_SwRst_Status
• Csu_Br_Error
• Safety_Chk

Black List Registers :

• Every other register in CSU Module, that is not covered in the above white list will be a black register.
• Every other register in PMU_GLOBAL Module,  that is not covered in the above white list will be a black register.
• RSA and RSA_CORE module registers are black.

Related Links

• Zynq UltraScale＋ MPSoC Power Management