drivers/gpu/drm/amd/display/dc/basics/conversion.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/amd/display/dc/basics/conversion.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/amd/display/dc/basics/conversion.c
Extension
.c
Size
4070 bytes
Lines
159
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

#include "dm_services.h"
#include "basics/conversion.h"

#define DIVIDER 10000

/* S2D13 value in [-3.00...0.9999] */
#define S2D13_MIN (-3 * DIVIDER)
#define S2D13_MAX (3 * DIVIDER)

uint16_t fixed_point_to_int_frac(
	struct fixed31_32 arg,
	uint8_t integer_bits,
	uint8_t fractional_bits)
{
	int32_t numerator;
	int32_t divisor = 1 << fractional_bits;

	uint16_t result;

	uint16_t d = (uint16_t)dc_fixpt_floor(
		dc_fixpt_abs(
			arg));

	if (d <= (uint16_t)(1 << integer_bits) - (1 / (uint16_t)divisor))
		numerator = (uint16_t)dc_fixpt_round(
			dc_fixpt_mul_int(
				arg,
				divisor));
	else {
		numerator = dc_fixpt_floor(
			dc_fixpt_sub(
				dc_fixpt_from_int(
					1LL << integer_bits),
				dc_fixpt_recip(
					dc_fixpt_from_int(
						divisor))));
	}

	if (numerator >= 0)
		result = (uint16_t)numerator;
	else
		result = (uint16_t)(
		(1 << (integer_bits + fractional_bits + 1)) + numerator);

	if ((result != 0) && dc_fixpt_lt(
		arg, dc_fixpt_zero))
		result |= 1 << (integer_bits + fractional_bits);

	return result;
}
/*
 * convert_float_matrix - This converts a double into HW register spec defined format S2D13.
 */
void convert_float_matrix(
	uint16_t *matrix,
	struct fixed31_32 *flt,
	uint32_t buffer_size)
{
	const struct fixed31_32 min_2_13 =
		dc_fixpt_from_fraction(S2D13_MIN, DIVIDER);
	const struct fixed31_32 max_2_13 =
		dc_fixpt_from_fraction(S2D13_MAX, DIVIDER);
	uint32_t i;

	for (i = 0; i < buffer_size; ++i) {
		uint32_t reg_value =
				fixed_point_to_int_frac(
					dc_fixpt_clamp(
						flt[i],
						min_2_13,
						max_2_13),
						2,
						13);

		matrix[i] = (uint16_t)reg_value;
	}
}

static struct fixed31_32 int_frac_to_fixed_point(uint16_t arg,
						 uint8_t integer_bits,
						 uint8_t fractional_bits)
{
	struct fixed31_32 result;
	uint16_t sign_mask = 1 << (fractional_bits + integer_bits);
	uint16_t value_mask = sign_mask - 1;

	result.value = (long long)(arg & value_mask) <<
		       (FIXED31_32_BITS_PER_FRACTIONAL_PART - fractional_bits);

	if (arg & sign_mask)

Annotation

Implementation Notes