drivers/gpu/drm/i915/display/intel_fixed.h

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/i915/display/intel_fixed.h

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/i915/display/intel_fixed.h
Extension
.h
Size
2836 bytes
Lines
149
Domain
Driver Families
Bucket
drivers/gpu
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

#ifndef _I915_FIXED_H_
#define _I915_FIXED_H_

#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/math64.h>
#include <linux/types.h>

typedef struct {
	u32 val;
} uint_fixed_16_16_t;

#define FP_16_16_MAX ((uint_fixed_16_16_t){ .val = UINT_MAX })

static inline bool is_fixed16_zero(uint_fixed_16_16_t val)
{
	return val.val == 0;
}

static inline uint_fixed_16_16_t u32_to_fixed16(u32 val)
{
	uint_fixed_16_16_t fp = { .val = val << 16 };

	WARN_ON(val > U16_MAX);

	return fp;
}

static inline u32 fixed16_to_u32_round_up(uint_fixed_16_16_t fp)
{
	return DIV_ROUND_UP(fp.val, 1 << 16);
}

static inline u32 fixed16_to_u32(uint_fixed_16_16_t fp)
{
	return fp.val >> 16;
}

static inline uint_fixed_16_16_t min_fixed16(uint_fixed_16_16_t min1,
					     uint_fixed_16_16_t min2)
{
	uint_fixed_16_16_t min = { .val = min(min1.val, min2.val) };

	return min;
}

static inline uint_fixed_16_16_t max_fixed16(uint_fixed_16_16_t max1,
					     uint_fixed_16_16_t max2)
{
	uint_fixed_16_16_t max = { .val = max(max1.val, max2.val) };

	return max;
}

static inline uint_fixed_16_16_t clamp_u64_to_fixed16(u64 val)
{
	uint_fixed_16_16_t fp = { .val = (u32)val };

	WARN_ON(val > U32_MAX);

	return fp;
}

static inline u32 div_round_up_fixed16(uint_fixed_16_16_t val,
				       uint_fixed_16_16_t d)
{
	return DIV_ROUND_UP(val.val, d.val);
}

static inline u32 mul_round_up_u32_fixed16(u32 val, uint_fixed_16_16_t mul)
{
	u64 tmp;

	tmp = mul_u32_u32(val, mul.val);
	tmp = DIV_ROUND_UP_ULL(tmp, 1 << 16);
	WARN_ON(tmp > U32_MAX);

	return (u32)tmp;
}

static inline uint_fixed_16_16_t mul_fixed16(uint_fixed_16_16_t val,
					     uint_fixed_16_16_t mul)
{
	u64 tmp;

	tmp = mul_u32_u32(val.val, mul.val);
	tmp = tmp >> 16;

	return clamp_u64_to_fixed16(tmp);
}

Annotation

Implementation Notes