drivers/video/fbdev/core/sysmem.h

File Facts

System

Linux kernel

Corpus path

drivers/video/fbdev/core/sysmem.h

Extension

.h

Size

978 bytes

Lines

40

Domain

Driver Families

Bucket

drivers/video

Inferred role

Driver Families: implementation source

Status

source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

• Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• No C-style include directives detected by the generator.

Detected Declarations

• struct fb_address
• function fb_address_init
• function fb_write_offset
• function fb_read_offset

Annotated Snippet

struct fb_address {
	void *address;
	int bits;
};

/* initialize the bit address pointer to the beginning of the frame buffer */
static inline struct fb_address fb_address_init(struct fb_info *p)
{
	void *base = p->screen_buffer;
	struct fb_address ptr;

	ptr.address = PTR_ALIGN_DOWN(base, BITS_PER_LONG / BITS_PER_BYTE);
	ptr.bits = (base - ptr.address) * BITS_PER_BYTE;
	return ptr;
}

/* framebuffer write access */
static inline void fb_write_offset(unsigned long val, int offset, const struct fb_address *dst)
{
	unsigned long *mem = dst->address;

	mem[offset] = val;
}

/* framebuffer read access */
static inline unsigned long fb_read_offset(int offset, const struct fb_address *src)
{
	unsigned long *mem = src->address;

	return mem[offset];
}

Annotation

• Detected declarations: `struct fb_address`, `function fb_address_init`, `function fb_write_offset`, `function fb_read_offset`.
• Atlas domain: Driver Families / drivers/video.
• Implementation status: source implementation candidate.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.