drm/msm/dp: move parity calculation to dp_utils

Parity calculation is necessary for VSC SDP implementation. Therefore
create new files dp_utils.c and dp_utils.h and move the parity
calculating functions here. This ensures that they are usable by SDP
programming in both dp_catalog.c and dp_audio.c

Changes in v3:
	- Change ordering of the header byte macros

Changes in v2:
	- Create new files dp_utils.c and dp_utils.h
	- Move the parity calculation to these new files instead of
	  having them in dp_catalog.c and dp_catalog.h

Signed-off-by: Paloma Arellano <quic_parellan@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/579617/
Link: https://lore.kernel.org/r/20240222194025.25329-13-quic_parellan@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

4 files changed, 112 insertions, 87 deletions

diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
index 543e04fa72e3..b21ae2880c71 100644
--- a/drivers/gpu/drm/msm/Makefile
+++ b/drivers/gpu/drm/msm/Makefile
@@ -127,7 +127,8 @@ msm-$(CONFIG_DRM_MSM_DP)+= dp/dp_aux.o \
 	dp/dp_drm.o \
 	dp/dp_link.o \
 	dp/dp_panel.o \
-	dp/dp_audio.o
+	dp/dp_audio.o \
+	dp/dp_utils.o
 
 msm-$(CONFIG_DRM_FBDEV_EMULATION) += msm_fbdev.o
 
diff --git a/drivers/gpu/drm/msm/dp/dp_audio.c b/drivers/gpu/drm/msm/dp/dp_audio.c
index 4a2e479723a8..7634e4b74208 100644
--- a/drivers/gpu/drm/msm/dp/dp_audio.c
+++ b/drivers/gpu/drm/msm/dp/dp_audio.c
@@ -15,13 +15,7 @@
 #include "dp_audio.h"
 #include "dp_panel.h"
 #include "dp_display.h"
-
-#define HEADER_BYTE_2_BIT	 0
-#define PARITY_BYTE_2_BIT	 8
-#define HEADER_BYTE_1_BIT	16
-#define PARITY_BYTE_1_BIT	24
-#define HEADER_BYTE_3_BIT	16
-#define PARITY_BYTE_3_BIT	24
+#include "dp_utils.h"
 
 struct dp_audio_private {
 	struct platform_device *audio_pdev;
@@ -36,71 +30,6 @@ struct dp_audio_private {
 	struct dp_audio dp_audio;
 };
 
-static u8 dp_audio_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;
-}
-
-static u8 dp_audio_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;
-}
-
-static u8 dp_audio_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 ^ dp_audio_get_g1_value(ci);
-		x0 = dp_audio_get_g0_value(ci);
-	}
-
-	parity_byte = x1 | (x0 << 4);
-
-	return parity_byte;
-}
-
 static u32 dp_audio_get_header(struct dp_catalog *catalog,
 		enum dp_catalog_audio_sdp_type sdp,
 		enum dp_catalog_audio_header_type header)
@@ -134,7 +63,7 @@ static void dp_audio_stream_sdp(struct dp_audio_private *audio)
 			DP_AUDIO_SDP_STREAM, DP_AUDIO_SDP_HEADER_1);
 
 	new_value = 0x02;
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_1_BIT)
 			| (parity_byte << PARITY_BYTE_1_BIT));
 	drm_dbg_dp(audio->drm_dev,
@@ -147,7 +76,7 @@ static void dp_audio_stream_sdp(struct dp_audio_private *audio)
 	value = dp_audio_get_header(catalog,
 			DP_AUDIO_SDP_STREAM, DP_AUDIO_SDP_HEADER_2);
 	new_value = value;
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_2_BIT)
 			| (parity_byte << PARITY_BYTE_2_BIT));
 	drm_dbg_dp(audio->drm_dev,
@@ -162,7 +91,7 @@ static void dp_audio_stream_sdp(struct dp_audio_private *audio)
 			DP_AUDIO_SDP_STREAM, DP_AUDIO_SDP_HEADER_3);
 
 	new_value = audio->channels - 1;
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_3_BIT)
 			| (parity_byte << PARITY_BYTE_3_BIT));
 	drm_dbg_dp(audio->drm_dev,
@@ -184,7 +113,7 @@ static void dp_audio_timestamp_sdp(struct dp_audio_private *audio)
 			DP_AUDIO_SDP_TIMESTAMP, DP_AUDIO_SDP_HEADER_1);
 
 	new_value = 0x1;
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_1_BIT)
 			| (parity_byte << PARITY_BYTE_1_BIT));
 	drm_dbg_dp(audio->drm_dev,
@@ -198,7 +127,7 @@ static void dp_audio_timestamp_sdp(struct dp_audio_private *audio)
 			DP_AUDIO_SDP_TIMESTAMP, DP_AUDIO_SDP_HEADER_2);
 
 	new_value = 0x17;
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_2_BIT)
 			| (parity_byte << PARITY_BYTE_2_BIT));
 	drm_dbg_dp(audio->drm_dev,
@@ -212,7 +141,7 @@ static void dp_audio_timestamp_sdp(struct dp_audio_private *audio)
 			DP_AUDIO_SDP_TIMESTAMP, DP_AUDIO_SDP_HEADER_3);
 
 	new_value = (0x0 | (0x11 << 2));
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_3_BIT)
 			| (parity_byte << PARITY_BYTE_3_BIT));
 	drm_dbg_dp(audio->drm_dev,
@@ -233,7 +162,7 @@ static void dp_audio_infoframe_sdp(struct dp_audio_private *audio)
 			DP_AUDIO_SDP_INFOFRAME, DP_AUDIO_SDP_HEADER_1);
 
 	new_value = 0x84;
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_1_BIT)
 			| (parity_byte << PARITY_BYTE_1_BIT));
 	drm_dbg_dp(audio->drm_dev,
@@ -247,7 +176,7 @@ static void dp_audio_infoframe_sdp(struct dp_audio_private *audio)
 			DP_AUDIO_SDP_INFOFRAME, DP_AUDIO_SDP_HEADER_2);
 
 	new_value = 0x1b;
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_2_BIT)
 			| (parity_byte << PARITY_BYTE_2_BIT));
 	drm_dbg_dp(audio->drm_dev,
@@ -261,7 +190,7 @@ static void dp_audio_infoframe_sdp(struct dp_audio_private *audio)
 			DP_AUDIO_SDP_INFOFRAME, DP_AUDIO_SDP_HEADER_3);
 
 	new_value = (0x0 | (0x11 << 2));
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_3_BIT)
 			| (parity_byte << PARITY_BYTE_3_BIT));
 	drm_dbg_dp(audio->drm_dev,
@@ -282,7 +211,7 @@ static void dp_audio_copy_management_sdp(struct dp_audio_private *audio)
 			DP_AUDIO_SDP_COPYMANAGEMENT, DP_AUDIO_SDP_HEADER_1);
 
 	new_value = 0x05;
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_1_BIT)
 			| (parity_byte << PARITY_BYTE_1_BIT));
 	drm_dbg_dp(audio->drm_dev,
@@ -296,7 +225,7 @@ static void dp_audio_copy_management_sdp(struct dp_audio_private *audio)
 			DP_AUDIO_SDP_COPYMANAGEMENT, DP_AUDIO_SDP_HEADER_2);
 
 	new_value = 0x0F;
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_2_BIT)
 			| (parity_byte << PARITY_BYTE_2_BIT));
 	drm_dbg_dp(audio->drm_dev,
@@ -310,7 +239,7 @@ static void dp_audio_copy_management_sdp(struct dp_audio_private *audio)
 			DP_AUDIO_SDP_COPYMANAGEMENT, DP_AUDIO_SDP_HEADER_3);
 
 	new_value = 0x0;
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_3_BIT)
 			| (parity_byte << PARITY_BYTE_3_BIT));
 	drm_dbg_dp(audio->drm_dev,
@@ -331,7 +260,7 @@ static void dp_audio_isrc_sdp(struct dp_audio_private *audio)
 			DP_AUDIO_SDP_ISRC, DP_AUDIO_SDP_HEADER_1);
 
 	new_value = 0x06;
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_1_BIT)
 			| (parity_byte << PARITY_BYTE_1_BIT));
 	drm_dbg_dp(audio->drm_dev,
@@ -345,7 +274,7 @@ static void dp_audio_isrc_sdp(struct dp_audio_private *audio)
 			DP_AUDIO_SDP_ISRC, DP_AUDIO_SDP_HEADER_2);
 
 	new_value = 0x0F;
-	parity_byte = dp_audio_calculate_parity(new_value);
+	parity_byte = dp_utils_calculate_parity(new_value);
 	value |= ((new_value << HEADER_BYTE_2_BIT)
 			| (parity_byte << PARITY_BYTE_2_BIT));
 	drm_dbg_dp(audio->drm_dev,
diff --git a/drivers/gpu/drm/msm/dp/dp_utils.c b/drivers/gpu/drm/msm/dp/dp_utils.c
new file mode 100644
index 000000000000..3a44fe738c00
--- /dev/null
+++ b/drivers/gpu/drm/msm/dp/dp_utils.c
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2024, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/types.h>
+
+#include "dp_utils.h"
+
+u8 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 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 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 ^ dp_utils_get_g1_value(ci);
+		x0 = dp_utils_get_g0_value(ci);
+	}
+
+	parity_byte = x1 | (x0 << 4);
+
+	return parity_byte;
+}
diff --git a/drivers/gpu/drm/msm/dp/dp_utils.h b/drivers/gpu/drm/msm/dp/dp_utils.h
new file mode 100644
index 000000000000..5a505cbf3432
--- /dev/null
+++ b/drivers/gpu/drm/msm/dp/dp_utils.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2024, The Linux Foundation. All rights reserved.
+ */
+
+#ifndef _DP_UTILS_H_
+#define _DP_UTILS_H_
+
+#define HEADER_BYTE_0_BIT	 0
+#define PARITY_BYTE_0_BIT	 8
+#define HEADER_BYTE_1_BIT	16
+#define PARITY_BYTE_1_BIT	24
+#define HEADER_BYTE_2_BIT	 0
+#define PARITY_BYTE_2_BIT	 8
+#define HEADER_BYTE_3_BIT	16
+#define PARITY_BYTE_3_BIT	24
+
+u8 dp_utils_get_g0_value(u8 data);
+u8 dp_utils_get_g1_value(u8 data);
+u8 dp_utils_calculate_parity(u32 data);
+
+#endif /* _DP_UTILS_H_ */