drivers/video/fbdev/c2p_core.h

Source file repositories/reference/linux-study-clean/drivers/video/fbdev/c2p_core.h

File Facts

System
Linux kernel
Corpus path
drivers/video/fbdev/c2p_core.h
Extension
.h
Size
2694 bytes
Lines
154
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.

Dependency Surface

Detected Declarations

Annotated Snippet

#include <linux/build_bug.h>


    /*
     *  Basic transpose step
     */

static inline void _transp(u32 d[], unsigned int i1, unsigned int i2,
			   unsigned int shift, u32 mask)
{
	u32 t = (d[i1] ^ (d[i2] >> shift)) & mask;

	d[i1] ^= t;
	d[i2] ^= t << shift;
}


static __always_inline u32 get_mask(unsigned int n)
{
	switch (n) {
	case 1:
		return 0x55555555;

	case 2:
		return 0x33333333;

	case 4:
		return 0x0f0f0f0f;

	case 8:
		return 0x00ff00ff;

	case 16:
		return 0x0000ffff;
	}

	BUILD_BUG();
	return 0;
}


    /*
     *  Transpose operations on 8 32-bit words
     */

static __always_inline void transp8(u32 d[], unsigned int n, unsigned int m)
{
	u32 mask = get_mask(n);

	switch (m) {
	case 1:
		/* First n x 1 block */
		_transp(d, 0, 1, n, mask);
		/* Second n x 1 block */
		_transp(d, 2, 3, n, mask);
		/* Third n x 1 block */
		_transp(d, 4, 5, n, mask);
		/* Fourth n x 1 block */
		_transp(d, 6, 7, n, mask);
		return;

	case 2:
		/* First n x 2 block */
		_transp(d, 0, 2, n, mask);
		_transp(d, 1, 3, n, mask);
		/* Second n x 2 block */
		_transp(d, 4, 6, n, mask);
		_transp(d, 5, 7, n, mask);
		return;

	case 4:
		/* Single n x 4 block */
		_transp(d, 0, 4, n, mask);
		_transp(d, 1, 5, n, mask);
		_transp(d, 2, 6, n, mask);
		_transp(d, 3, 7, n, mask);
		return;
	}

	BUILD_BUG();
}


    /*
     *  Transpose operations on 4 32-bit words
     */

static __always_inline void transp4(u32 d[], unsigned int n, unsigned int m)
{
	u32 mask = get_mask(n);

Annotation

Implementation Notes