drivers/gpu/drm/msm/dp/dp_utils.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/msm/dp/dp_utils.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/msm/dp/dp_utils.c
Extension
.c
Size
1842 bytes
Lines
89
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 <linux/types.h>

#include "dp_utils.h"

#define DP_SDP_HEADER_SIZE		8

u8 msm_dp_utils_get_g0_value(u8 data)
{
	u8 c[4];
	u8 g[4];
	u8 ret_data = 0;
	u8 i;

	for (i = 0; i < 4; i++)
		c[i] = (data >> i) & 0x01;

	g[0] = c[3];
	g[1] = c[0] ^ c[3];
	g[2] = c[1];
	g[3] = c[2];

	for (i = 0; i < 4; i++)
		ret_data = ((g[i] & 0x01) << i) | ret_data;

	return ret_data;
}

u8 msm_dp_utils_get_g1_value(u8 data)
{
	u8 c[4];
	u8 g[4];
	u8 ret_data = 0;
	u8 i;

	for (i = 0; i < 4; i++)
		c[i] = (data >> i) & 0x01;

	g[0] = c[0] ^ c[3];
	g[1] = c[0] ^ c[1] ^ c[3];
	g[2] = c[1] ^ c[2];
	g[3] = c[2] ^ c[3];

	for (i = 0; i < 4; i++)
		ret_data = ((g[i] & 0x01) << i) | ret_data;

	return ret_data;
}

u8 msm_dp_utils_calculate_parity(u32 data)
{
	u8 x0 = 0;
	u8 x1 = 0;
	u8 ci = 0;
	u8 iData = 0;
	u8 i = 0;
	u8 parity_byte;
	u8 num_byte = (data & 0xFF00) > 0 ? 8 : 2;

	for (i = 0; i < num_byte; i++) {
		iData = (data >> i * 4) & 0xF;

		ci = iData ^ x1;
		x1 = x0 ^ msm_dp_utils_get_g1_value(ci);
		x0 = msm_dp_utils_get_g0_value(ci);
	}

	parity_byte = x1 | (x0 << 4);

	return parity_byte;
}

void msm_dp_utils_pack_sdp_header(struct dp_sdp_header *sdp_header, u32 header_buff[2])
{
	header_buff[0] = FIELD_PREP(HEADER_0_MASK, sdp_header->HB0) |
		FIELD_PREP(PARITY_0_MASK, msm_dp_utils_calculate_parity(sdp_header->HB0)) |
		FIELD_PREP(HEADER_1_MASK, sdp_header->HB1) |
		FIELD_PREP(PARITY_1_MASK, msm_dp_utils_calculate_parity(sdp_header->HB1));

	header_buff[1] = FIELD_PREP(HEADER_2_MASK, sdp_header->HB2) |
		FIELD_PREP(PARITY_2_MASK, msm_dp_utils_calculate_parity(sdp_header->HB2)) |
		FIELD_PREP(HEADER_3_MASK, sdp_header->HB3) |
		FIELD_PREP(PARITY_3_MASK, msm_dp_utils_calculate_parity(sdp_header->HB3));
}

Annotation

Implementation Notes