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As the kernel runs, physical memory becomes increasingly fragmented. Certain devices, such as those using DMA, require large contiguous physical memory blocks. When such memory is unavailable at runtime, the device may fail to operate. To address this, Linux provides a mechanism to reserve a dedicated region of physical memory for specific devi ...

Peripheral Configuration The ST7789 display is driven by the nRF54L15's high-speed SPI00 peripheral, capable of operating at 32 MHz. A critical aspect of configuring SPI00 is ensuring the correct pins and drive strength are used. First, the GPIO pins must be from the P2 port. Second, the high-drive mode must be enabled to ensure reliable signal ...

Understanding the Platform Bus The platform bus is a virtual bus within the Linux kernel architecture, designed to unify the device and driver model. Unlike physical buses such as PCI or USB, the platform bus does not correspond to any physical hardware. It exists to manage devices that do not naturally fit into other bus models, ensuring a con ...

TF-A Porting for STM32MP157 This document covers the TF-A (Trusted Firmware-A) porting process for the STM32MP157DAC-based development board. Prerequisites Obtain the STM32MP1 Developer Package containing the compiler SDK and official source code: STM32MP1 OpenSTLinux Developer Package https://www.st.com.cn/zh/embedded-software/stm32mp1dev.htm ...