97 lines
1.9 KiB
C
97 lines
1.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (c) 2024, The Linux Foundation. All rights reserved.
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*/
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#include <linux/types.h>
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#include "dp_utils.h"
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#define DP_SDP_HEADER_SIZE 8
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u8 msm_dp_utils_get_g0_value(u8 data)
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{
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u8 c[4];
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u8 g[4];
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u8 ret_data = 0;
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u8 i;
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for (i = 0; i < 4; i++)
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c[i] = (data >> i) & 0x01;
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g[0] = c[3];
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g[1] = c[0] ^ c[3];
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g[2] = c[1];
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g[3] = c[2];
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for (i = 0; i < 4; i++)
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ret_data = ((g[i] & 0x01) << i) | ret_data;
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return ret_data;
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}
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u8 msm_dp_utils_get_g1_value(u8 data)
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{
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u8 c[4];
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u8 g[4];
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u8 ret_data = 0;
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u8 i;
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for (i = 0; i < 4; i++)
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c[i] = (data >> i) & 0x01;
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g[0] = c[0] ^ c[3];
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g[1] = c[0] ^ c[1] ^ c[3];
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g[2] = c[1] ^ c[2];
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g[3] = c[2] ^ c[3];
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for (i = 0; i < 4; i++)
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ret_data = ((g[i] & 0x01) << i) | ret_data;
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return ret_data;
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}
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u8 msm_dp_utils_calculate_parity(u32 data)
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{
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u8 x0 = 0;
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u8 x1 = 0;
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u8 ci = 0;
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u8 iData = 0;
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u8 i = 0;
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u8 parity_byte;
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u8 num_byte = (data & 0xFF00) > 0 ? 8 : 2;
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for (i = 0; i < num_byte; i++) {
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iData = (data >> i * 4) & 0xF;
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ci = iData ^ x1;
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x1 = x0 ^ msm_dp_utils_get_g1_value(ci);
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x0 = msm_dp_utils_get_g0_value(ci);
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}
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parity_byte = x1 | (x0 << 4);
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return parity_byte;
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}
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ssize_t msm_dp_utils_pack_sdp_header(struct dp_sdp_header *sdp_header, u32 *header_buff)
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{
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size_t length;
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length = sizeof(header_buff);
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if (length < DP_SDP_HEADER_SIZE)
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return -ENOSPC;
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header_buff[0] = FIELD_PREP(HEADER_0_MASK, sdp_header->HB0) |
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FIELD_PREP(PARITY_0_MASK, msm_dp_utils_calculate_parity(sdp_header->HB0)) |
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FIELD_PREP(HEADER_1_MASK, sdp_header->HB1) |
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FIELD_PREP(PARITY_1_MASK, msm_dp_utils_calculate_parity(sdp_header->HB1));
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header_buff[1] = FIELD_PREP(HEADER_2_MASK, sdp_header->HB2) |
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FIELD_PREP(PARITY_2_MASK, msm_dp_utils_calculate_parity(sdp_header->HB2)) |
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FIELD_PREP(HEADER_3_MASK, sdp_header->HB3) |
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FIELD_PREP(PARITY_3_MASK, msm_dp_utils_calculate_parity(sdp_header->HB3));
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return length;
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}
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