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How are devices represented in a device tree?
Every device in the system is represented by a device tree node. The next step is to populate the tree with a node for each of the devices. For now, the new nodes will be left empty until we can talk about how address ranges and irqs are handled.
What does compatible mean in elinux device tree?
Every node in the tree that represents a device is required to have the compatible property. compatible is the key an operating system uses to decide which device driver to bind to a device. compatible is a list of strings. The first string in the list specifies the exact device that the node represents in the form ” , “.
How to reserve memory in device tree 2017.4?
I am using Ultrazed_SOM board with Peatlinux 2017.4 and Vivado 2017.4. Now I want to reserve the memory area of 0x800000000- 0x860000000. I added mem=1536M in the bootargs, and in the startup log, I can see the reserved memroy is from 0xc000000000-0xc060000000. Does anyone knows how to make the reservation at the right place? (0x800000000)
Why is it important to use the device tree in Linux?
Using it allows board and device support to become data driven; to make setup decisions based on data passed into the kernel instead of on per-machine hard coded selections. Ideally, data driven platform setup should result in less code duplication and make it easier to support a wide range of hardware with a single kernel image.
How much memory can be mapped with logical addresses?
The limitation on how much memory can be directly mapped with logical addresses remains, however. Only the lowest portion of memory (up to 1 or 2 GB, depending on the hardware and the kernel configuration) has logical addresses; [ 2] the rest (high memory) does not.
Where can I find the device tree in Linux?
The device tree comes in three forms: In a normal flow, the DTS file is edited and compiled into a DTB file using a special compiler which comes with the Linux kernel sources. On a Xillinux distribution, it’s available at /usr/src/kernels/3.3.0-xillinux-1.0+/scripts/dtc/ (or similar).
Where can I find the device tree compiler?
In a normal flow, the DTS file is edited and compiled into a DTB file using a special compiler which comes with the Linux kernel sources. On a Xillinux distribution, it’s available at /usr/src/kernels/3.3.0-xillinux-1.0+/scripts/dtc/ (or similar). The device tree compiler can be downloaded and built separately with.