There are several kinds of addresses involved in the dma api, and it’s important to understand the differences The kernel normally uses virtual addresses. This thesis proposes a method to represent complex dma driver source code as an abstract mathematical model in the formal analysis tool hol4 (where users can define models and prove properties about them with hol4 and checking the correctness of the proofs). To overcome this, a direct memory access (dma) controller is used It enables i/o devices to transfer data directly to or from memory without heavy cpu involvement, improving speed and efficiency It generates memory addresses and controls timing for efficient data movement.
Data can be quickly moved by dma without any cpu action, keeping cpu resources free for other operations This article uses the stm32l476 device as an example The stm32l476 device embeds 2 dmas Each channel is dedicated to managing memory access requests from one or more peripherals. Rather than allocating in units of a page or more using dma_alloc_coherent (), you can use dma pools. The dma framework provides a generic dma device framework which supports both physical (hardware) and virtual (software) dma devices, as well as a generic dma api which allows dma devices to be managed and configured, and supports dma operations to be provisioned on dma poll mode driver.
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