[PATCH v4 01/12] drm/i915/dip: Add new file to handle Data Island Packet hardware

[Ankit Nautiyal <ankit.k.nautiyal@intel.com>]

Add new files intel_dip.c, intel_dip.h, and intel_dip_regs.h to handle
low level hardware programming related to Data Island Packets.

Currently only programming of the Transmission Line for HDMI 2.1
Extended Metadata Packet (EMP) and DP Adaptive-Sync Secondary Data
Packet (SDP) is added (MMIO register EMP_AS_SDP_TL).

This will serve as a common place for DIP related code, which is currently
scattered across DP and HDMI files. A TODO has been added for extracting
the remaining DIP helpers.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
---
 drivers/gpu/drm/i915/Makefile                 |  1 +
 drivers/gpu/drm/i915/display/intel_dip.c      | 39 +++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_dip.h      | 38 ++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_dip_regs.h | 17 ++++++++
 drivers/gpu/drm/i915/display/intel_vrr.c      |  1 +
 drivers/gpu/drm/i915/display/intel_vrr_regs.h |  6 ---
 drivers/gpu/drm/xe/Makefile                   |  1 +
 7 files changed, 97 insertions(+), 6 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/display/intel_dip.c
 create mode 100644 drivers/gpu/drm/i915/display/intel_dip.h
 create mode 100644 drivers/gpu/drm/i915/display/intel_dip_regs.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 07802a7f4ce5..04624d35447c 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -349,6 +349,7 @@ i915-y += \
 	display/intel_cx0_phy.o \
 	display/intel_ddi.o \
 	display/intel_ddi_buf_trans.o \
+	display/intel_dip.o \
 	display/intel_display_device.o \
 	display/intel_display_trace.o \
 	display/intel_dkl_phy.o \
diff --git a/drivers/gpu/drm/i915/display/intel_dip.c b/drivers/gpu/drm/i915/display/intel_dip.c
new file mode 100644
index 000000000000..2e2bdb2b199c
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_dip.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2026 Intel Corporation
+ *
+ */
+
+#include "intel_de.h"
+#include "intel_dip.h"
+#include "intel_dip_regs.h"
+#include "intel_display_types.h"
+
+u16 intel_dip_read_emp_as_sdp_tl(const struct intel_crtc_state *crtc_state)
+{
+	struct intel_display *display = to_intel_display(crtc_state);
+	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
+	u32 val;
+
+	if (!HAS_EMP_AS_SDP_TL(display))
+		return 0;
+
+	val = intel_de_read(display, EMP_AS_SDP_TL(display, cpu_transcoder));
+	return REG_FIELD_GET(EMP_AS_SDP_DB_TL_MASK, val);
+}
+
+void intel_dip_write_emp_as_sdp_tl(const struct intel_crtc_state *crtc_state)
+{
+	struct intel_display *display = to_intel_display(crtc_state);
+	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
+
+	if (!HAS_EMP_AS_SDP_TL(display))
+		return;
+	/*
+	 * Since currently we support VRR only for DP/eDP, so this is programmed
+	 * only for Adaptive Sync SDP to Vsync start.
+	 */
+	intel_de_write(display,
+		       EMP_AS_SDP_TL(display, cpu_transcoder),
+		       EMP_AS_SDP_DB_TL(crtc_state->vrr.vsync_start));
+}
diff --git a/drivers/gpu/drm/i915/display/intel_dip.h b/drivers/gpu/drm/i915/display/intel_dip.h
new file mode 100644
index 000000000000..25bae4a04d6b
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_dip.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2026 Intel Corporation
+ */
+
+#ifndef __INTEL_DIP_H__
+#define __INTEL_DIP_H__
+
+#include "intel_display_device.h"
+
+/*
+ * Video DIP (Data Island Packet) helpers.
+ *
+ * This file contains helpers for programming video DIP related hardware.
+ *
+ * TODO: Currently, this is only used for programming EMP_AS_SDP_TL i.e. to
+ * program Transmission Line for HDMI 2.1 Extended Metadata Packet (EMP) and
+ * DP Adaptive Sync (AS) Secondary Data Packet (SDP). However, all low level
+ * DIP buffer read/write and related helpers should be extracted here later.
+ */
+
+struct intel_crtc_state;
+
+/*
+ * EMP AS SDP TL: Extended Metadata Packet (EMP) Adaptive Sync (AS)
+ * Secondary Data Packet (SDP) Transmission Line (TL).
+ *
+ * Starting with BMG (display ver 14.01) and LNL+ (display ver 20+),
+ * the AS SDP transmission line is programmable via the EMP AS SDP TL
+ * register.
+ */
+#define HAS_EMP_AS_SDP_TL(__display)	(DISPLAY_VERx100(__display) == 1401 || \
+					 DISPLAY_VER(__display) >= 20)
+
+u16 intel_dip_read_emp_as_sdp_tl(const struct intel_crtc_state *crtc_state);
+void intel_dip_write_emp_as_sdp_tl(const struct intel_crtc_state *crtc_state);
+
+#endif /* __INTEL_DIP_H__ */
diff --git a/drivers/gpu/drm/i915/display/intel_dip_regs.h b/drivers/gpu/drm/i915/display/intel_dip_regs.h
new file mode 100644
index 000000000000..85dcbf42e77d
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_dip_regs.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2026 Intel Corporation
+ */
+
+#ifndef __INTEL_DIP_REGS_H__
+#define __INTEL_DIP_REGS_H__
+
+#include "intel_display_reg_defs.h"
+
+/* EMP (Extended Metadata Packet) AS (Adaptive Sync) SDP Transmission Line */
+#define _EMP_AS_SDP_TL_A			0x60204
+#define EMP_AS_SDP_TL(display, trans)		_MMIO_TRANS2((display), (trans), _EMP_AS_SDP_TL_A)
+#define   EMP_AS_SDP_DB_TL_MASK			REG_GENMASK(12, 0)
+#define   EMP_AS_SDP_DB_TL(db_transmit_line)	REG_FIELD_PREP(EMP_AS_SDP_DB_TL_MASK, (db_transmit_line))
+
+#endif /* __INTEL_DIP_REGS_H__ */
diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index e03b5daac5be..6130854a706c 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -9,6 +9,7 @@
 #include "intel_alpm.h"
 #include "intel_crtc.h"
 #include "intel_de.h"
+#include "intel_dip_regs.h"
 #include "intel_display_regs.h"
 #include "intel_display_types.h"
 #include "intel_dmc.h"
diff --git a/drivers/gpu/drm/i915/display/intel_vrr_regs.h b/drivers/gpu/drm/i915/display/intel_vrr_regs.h
index 9d4d6573a149..ba8631cbc672 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr_regs.h
+++ b/drivers/gpu/drm/i915/display/intel_vrr_regs.h
@@ -174,12 +174,6 @@
 #define   VRR_VSYNC_START_MASK			REG_GENMASK(12, 0)
 #define   VRR_VSYNC_START(vsync_start)		REG_FIELD_PREP(VRR_VSYNC_START_MASK, (vsync_start))
 
-/* Common register for HDMI EMP and DP AS SDP */
-#define _EMP_AS_SDP_TL_A			0x60204
-#define EMP_AS_SDP_TL(display, trans)		_MMIO_TRANS2((display), (trans), _EMP_AS_SDP_TL_A)
-#define   EMP_AS_SDP_DB_TL_MASK			REG_GENMASK(12, 0)
-#define   EMP_AS_SDP_DB_TL(db_transmit_line)	REG_FIELD_PREP(EMP_AS_SDP_DB_TL_MASK, (db_transmit_line))
-
 #define _TRANS_CMRR_M_LO_A			0x604F0
 #define TRANS_CMRR_M_LO(display, trans)		_MMIO_TRANS2((display), (trans), _TRANS_CMRR_M_LO_A)
 
diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
index 09661f079d03..9e826d164951 100644
--- a/drivers/gpu/drm/xe/Makefile
+++ b/drivers/gpu/drm/xe/Makefile
@@ -256,6 +256,7 @@ xe-$(CONFIG_DRM_XE_DISPLAY) += \
 	i915-display/intel_ddi.o \
 	i915-display/intel_ddi_buf_trans.o \
 	i915-display/intel_de.o \
+	i915-display/intel_dip.o \
 	i915-display/intel_display.o \
 	i915-display/intel_display_conversion.o \
 	i915-display/intel_display_device.o \
-- 
2.45.2