How daffasysgoogle/kernel-linux works
Linux is a general-purpose operating-system kernel: it mediates hardware access and provides services to userspace and other kernel subsystems. The sampled code shows several independent runtime areas rather than one end-to-end application: DMA transfers, queued crypto requests, SPI controller operation, USB mass storage, ROMFS reads, and GPU engine management. The graph keeps those domains distinct and shows only relationships supported by the excerpts. The file tree and samples are incomplete, so important wiring and other kernel capabilities are not mapped here.
Main entry points: storage.c ROMFS storage access · f_mass_storage.c USB mass storage · dmaengine.c DMAengine core · industrialio-buffer-dmaengine.c IIO DMA buffer
Components 16
DMA transfers
- IIO DMA buffer
drivers/iio/buffer/industrialio-buffer-dmaengine.c - DMAengine core
drivers/dma/dmaengine.c - CCP DMA provider
drivers/crypto/ccp/ccp-dmaengine.c - AMD PTDMA provider
drivers/dma/amd/ptdma/ptdma-dmaengine.c
Crypto requests
- Crypto engine API
include/crypto/engine.h - Crypto engine framework
crypto/crypto_engine.c
Device I/O
- SPI Engine controller
drivers/spi/spi-axi-spi-engine.c - APU board GPIO
drivers/platform/x86/pcengines-apuv2.c
Storage
- USB mass storage
drivers/usb/gadget/function/f_mass_storage.c - ROMFS storage access
fs/romfs/storage.c
GPU engines
- i915 GPU engines
drivers/gpu/drm/i915/gt/intel_engine_cs.c - Xe GPU engines
drivers/gpu/drm/xe/xe_hw_engine.c
Other components
- Block device
- MTD device
- USB host
- Backing medium
Connections 7
- IIO DMA buffer → DMAengine core: submits transfers
- CCP DMA provider → DMAengine core: registers channels
- Crypto engine framework → Crypto engine API: implements API
- USB host → USB mass storage: sends commands
- USB mass storage → Backing medium: reads and writes
- ROMFS storage access → Block device: reads image
- ROMFS storage access → MTD device: reads image