RK3588
Motherboard
Exploration
Secret
On May 20, 2023, at 20:00, the first lecture of “Understanding Computer Systems Under the Debugger” started on time via Tencent Meeting. Despite being a special day, many tech enthusiasts logged in on time.
The theme of the first lecture is: Understanding the Universe on the Board, Taking the Youlan as an Example. From this title, we can see the philosophy of Ge Wu, using the implementation of RK3588 in the Youlan codebook as a concrete example to learn.
Overview
Overview
When we open the back cover of the Youlan and remove its heat sink, we can see the Youlan motherboard. “Understanding the Universe on the Board” actually means discussing various components on the board as examples to explain the Youlan system, using a visible and tangible way to illustrate what components are needed to implement a laptop computer using a typical ARM SoC.
The central piece is our protagonist—the RK3588 SoC from Rockchip, a highly integrated system-on-chip with an 8nm process technology. Surrounding it are three larger chips that support the whole system, like stars supporting the moon. First, let’s talk about the three larger chips that are closest to it. The black chip in the upper right corner is a 128GB eMMC flash memory used to store the Linux kernel.
Moreover, the default home directory is also included here. It acts as external storage, capable of permanently storing data. The two chips in the lower left corner are the 16GB DDR memory for the Youlan, which is currently the maximum memory that RK3588 can achieve. Through these key components on the board, we can gain a deeper understanding of the principles of registers.
Three Major Components
Von Neumann Architecture
Three Major Components
Today, mainstream desktop computer systems use the Von Neumann architecture. The Von Neumann architecture abstracts the computer system into the diagram in front of us, with the central arithmetic unit (CA) and the central control unit (CC) represented by C, collectively known as CPU today. Close to the CPU is the memory, represented by M in Von Neumann’s diagram. Then he drew two Rs, which we call external storage today, accessed through I/O. In this way, Von Neumann summarized the entire computer system into three major components.
Although we still follow the Von Neumann architecture today, there are differences. For example, external storage is getting closer to the central processor. In traditional PCs, the hard drive is far away—hanging outside the motherboard. But today, for Youlan, the external storage is also close to the CPU. This shows that computer systems are evolving even while the overall structure remains unchanged.
Protagonist RK3588 SoC
Next, Teacher Zhang provided a detailed introduction to the three major components.
Starting with our protagonist SoC, the RK3588 is not only well-known in China but also globally. It is rare to achieve such good cost-performance ratio with ARM SoCs. Before the RK3588, achieving an ARM laptop system was not feasible due to performance limitations. To create a laptop-style computer system, the central SoC chip must meet a certain performance level, and previous models (including the 3399) fell short. The 3588 has truly reached this level. Of course, achieving this level is not only due to its eight cores but also involves other fundamental components such as GPU, VPU, HDMI, USB, and PCIe. Only when all these conditions are met can it be used to implement a computer system like Youlan with decent performance.
Today, making SoCs is challenging due to the balance required: how to select mature technologies and integrate them together. This integration is not merely stacking them; they must complement each other to achieve a synergy of 1+1>2. Finally, it must reach a good cost-performance ratio, not too expensive, and withstand market scrutiny. If the cost-performance ratio is unsuitable, it does not meet market requirements.
RK3588 performs very well in this regard, meticulously selecting components, combining them, and refining them, including debugging support and the stability of peripheral components, which is highly impressive.
This diagram is the logical diagram of RK3588, not the actual physical layout of transistors.
Memory
The Speed of Accessing Memory
Determines the Speed of the Entire System
After discussing the central part of the three major components, let’s talk about memory.
Memory involves DDR technology, and achieving G-level large-scale memory today typically uses DDR technology. The 3588 integrates a DDR controller, which is used to communicate with DDR chips. Accessing memory is crucial for performance because software needs to interact with memory; code and data must access memory. The speed of memory access determines the speed of the entire system and becomes the most critical constraint on the entire system. Therefore, to improve performance, DDR controllers have become increasingly complex.
Storage
External Storage for Permanent Data Storage
After delving into memory, let’s turn to eMMC external storage. When the Youlan is shipped, we place the Linux kernel on the eMMC flash memory. The eMMC flash also has an MMC controller, sourced from the USA, which Rockchip has used for a long time. This controller forms an MMC protocol bus that can connect multiple devices. The Youlan actually connects three types of devices: one is the eMMC flash memory, another is the SD card, which may or may not be inserted, and the third is Wi-Fi.
During the explanation of external storage, Teacher Zhang shared an optimization method suitable for the startup phase to improve access speed. Due to time constraints, we cannot delve too deeply into each aspect in the first lecture, but it can open our minds; these topics are worth studying.
Power Supply
Power Supply Occupying Nearly Half of the Signals
is Critical
After introducing the three major components of RK3588—SoC, memory, and external storage, Teacher Zhang guided us to explore from the perspective of power supply.
Returning to the protagonist SoC, its data sheet also provides external package signals, still using the BGA mode. Its packaged size is 21.45mm * 21.45mm, which is square. Packaged chips are not necessarily square; for example, many of Intel’s SoCs today are not square but rectangular. RK3588 is still packaged in a square format, with a size of approximately 2cm * 2cm, making it the largest chip on the Youlan motherboard. The packaged format is called BGA1088, indicating it has a total of 1088 signals. In comparison, GDK3 has only 48 signals, while Youlan has over a thousand signals, indicating its complexity. Of course, the X86 currently has over two thousand signals. We can imagine that combining such a chip with a motherboard requires very precise craftsmanship.
What are these thousand-plus signals for? Firstly, the aforementioned DDR controller occupies some signals; then PCIe also requires some signals; USB, including GPU display signals, also occupy some signals; in addition, approximately four to five hundred signals are related to power supply or grounding. In other words, about half of these thousand-plus signals are related to power supply. This leads to an exploration of power supply issues, with Teacher Zhang using the dual 806 power control scheme used in Youlan as a specific example for explanation.
Conclude
Summary
The RK3588 is an impressive SoC, not only in our view but also in the eyes of many international peers.
For example, a recent article introducing the RK3588 was published on the famous site tomshardware. This may be a promotional piece by Orange Pi, but regardless, the RK3588 is gaining popularity worldwide. Therefore, choosing Youlan also means learning with peers worldwide; it is a highly cost-effective SoC in the contemporary ARM ecosystem.
The above two images are the lecture notes and screenshots from the first lecture.
Finally, quoting a phrase from Confucius: “Although all principles are just one principle, scholars should understand the thousands of principles and assemble them together to see that it is one principle. Not understanding those principles but only focusing on that one principle is just empty imagination.”
Many people feel confused: “Teacher Zhang, give me an idea, how can I improve?” Just as Confucius said, this is just “empty imagination.” One must determine a direction and delve into it. If you want to use X86, choose an X86 to learn; if you want to use ARM, choose an ARM. Dig deeper; today you understand flash memory, tomorrow you understand hard drives, and the day after you learn printk. Accumulating knowledge over time leads to a comprehensive understanding.
Finally, I recommend Youlan’s learning resources. We will continue writing these articles.
Youlan User Guide:
https://www.nanocode.cn/wiki/docs/youlan
The above is an overview of the first lecture on RK3588. If you are interested in the subsequent content, you can also enroll in our course “Understanding RK3588 and LINUX 5.10 Under the Debugger.”
By purchasing the Youlan codebook, you can become a member of the Lan House and grow with many technical experts.
To purchase, visit the Taobao Ge You store:
https://m.tb.cn/h.Uuv7fit?tk=N1iIdn8t4CI
Shengge Academy is a knowledge-sharing platform under Ge Du Technology, based on the educational philosophy of “Ge Wu Zhi Zhi” (to understand the principles of things).
In line with the idea of inheriting the wisdom of the sages, Shengge Academy strives to closely integrate the essence of traditional culture with modern technology, using traditional culture and humanistic sentiment to explain modern technology, and using modern technology to disseminate traditional culture.
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