confit.txt file

RDK uses a configuration file config.txt to set some system configurations at boot time. config.txt is read during the uboot phase and supports modifying the configuration of the device tree, IO pin status, ION memory, CPU frequency, etc.

This file is usually accessible from Linux as /boot/config.txt and must be edited as the root user.

If you configure settings in config.txt, but the file does not exist yet, just create it as a new text file.

1. Note

1. The config.txt configuration file is only applicable to the RDK X3 and RDK X3 Module development boards, not to the RDK Ultra development board.
2. The system version is not lower than 2.1.0.
3. If you add filter items to this configuration file, please pay attention to whether the configuration items will be filtered out when using the srpi-config tool.

2. Device tree configuration

• dtdebug

dtdebug If non-zero, configuration logs will be output during the device tree configuration process at the uboot stage.

dtdebug=1

• dtoverlay

Support device tree overlay, providing a more flexible way to adjust the device tree.

For example, adjust the size of the ION memory through ion_resize. The following configuration will change the ION memory size to 1GB.

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dtoverlay=ion_resize,size=0x40000000

• dtparam

Supports enabling and disabling of uart, i2c, spi, i2s and other buses.

Currently supported option parameters: uart3, spi0, spi1, spi2, i2c0, i2c1, i2c2, i2c3, i2c4, i2c5, i2s0, i2s1

For example, to disable serial port 3.

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dtparam=uart3=off

Eg, open i2c5:

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dtparam=i2c5=on

3. CPU frequency

• arm_boost

When set to 1, overclocking is enabled. The maximum frequency of RDK v1.x is increased to 1.5GHz, and the maximum frequency of RDK V2.0 and RDK Module is increased to 1.8GHz.

By cat /sys/devices/system/cpu/cpufreq/scaling_boost_frequencies to get which higher CPU frequencies will be opened after enabling boost.

Overclocking is not enabled by default. It is enabled when arm_boost is set to 1, for example.

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arm_boost=1

• governor

The CPU frequency scheduling method can be selected by conservative ondemand userspace powersave performance schedutil.

The configurable modes can be obtained through cat /sys/devices/system/cpu/cpufreq/scaling_available_governors.

For example, to set CPU to run in performance mode.

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governor=performance

• frequency

When governor is set to userspace, you can use this option to set CPU to run at a fixed frequency. Currently, you can generally set frequencies such as 240000 500000 800000 1000000 1200000 1500000 1800000.

You can get the list of frequencies that can be set through cat /sys/devices/system/cpu/cpufreq/scaling_available_frequencies.

For example, set CPU to run at 1GHz with reduced frequency.

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governor=userspace
frequency=1000000

4.IO initialization

• gpio

Support setting IO function multiplexing, output, output mode, output high, low level, pull-up and pull-down modes.

x
gpio:
ip - Input                             Set to input mode
op - Output                            Set to output mode
f0-f3 - Func0-Func3                    Set function reuse, f3 functions are all set to io mode
dh - Driving high (for outputs)        Output high level
dl - Driving low (for outputs)         Output low level
pu - Pull up                           Push-pull pull-up
pd - Pull down                         Push-pull pull-down
pn/np - No pull                        No pull-up or pull-down

• Example

Configure GPIO5 and GPIO6 on the 40Pin pin to IO mode.

x
gpio=5=f3
gpio=6=f3
# For continuous pins, you can also use the following configuration
gpio=5-6=f3

Configure GPIO5 on the 40Pin pin as input mode.

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gpio=5=f3
gpio=5=ip

Configure GPIO6 on the 40Pin pin to output mode and output low level.

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gpio=6=f3
gpio=6=op,dl

Configure GPIO6 on the 40Pin pin to output mode, output high level, and set pull-up.

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gpio=6=f3
gpio=6=op,dl,pu

5. Temperature control

• throttling_temp

The system CPU and BPU frequency reduction temperature point.

When the temperature exceeds this point, the CPU and BPU will reduce their operating frequencies to reduce power consumption. The CPU will be reduced to 240MHz and the BPU will be reduced to 400MHz.

• shutdown_temp

System shutdown temperature point. If the temperature exceeds this point, the system will automatically shut down to protect the chip and hardware.

It is recommended to do a good job of heat dissipation for the device to avoid device shutdown, because the device will not automatically restart after shutdown.

6. Option filter

Supports using [] to set filter items. The filter item settings need to be added at the end of the configuration file, because the part of the file that does not have filter items added belongs to all.

Once the filter setting is added, the subsequent configuration only belongs to the filter attribute until the end of the configuration file or another filter item is set.

Currently supported filter items are distinguished by hardware model, and the following filter items are supported.