drm/i915/display: Add APIs to be used by gvt to get the register offsets

GVT code uses macros for register offsets that require display internal
structures. This makes clean separation of display code and
modularization difficult.

Introduce APIs to abstract offset calculations:
- intel_display_device_pipe_offset()
- intel_display_device_trans_offset()
- intel_display_device_cursor_offset()
- intel_display_device_mmio_base()

These APIs return absolute base offsets for the respective register
groups, allowing GVT to compute MMIO addresses without using internal
macros or struct fields. This prepares the path to separate
display-dependent code from i915/gvt/*.

v2:
- Build GVT APIs only when GVT is actually enabled. (Jani)

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com> (#v1)
Link: https://patch.msgid.link/20251219060302.2365123-3-ankit.k.nautiyal@intel.com

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index fb2b215930207fead695980cc43374b98a850e94..fad3cf0e9ab21d5cb06fda6ae563446eb4a0c3ec 100644 (file)
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -383,6 +383,9 @@ i915-y += \
 i915-$(CONFIG_DRM_I915_DP_TUNNEL) += \
        display/intel_dp_tunnel.o
 
+i915-$(CONFIG_DRM_I915_GVT) += \
+       display/intel_gvt_api.o
+
 i915-y += \
        i915_perf.o
 

diff --git a/drivers/gpu/drm/i915/display/intel_display_limits.c b/drivers/gpu/drm/i915/display/intel_display_limits.c
new file mode 100644 (file)
index 0000000..e69de29

diff --git a/drivers/gpu/drm/i915/display/intel_gvt_api.c b/drivers/gpu/drm/i915/display/intel_gvt_api.c
new file mode 100644 (file)
index 0000000..b1bfe48
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_gvt_api.c
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+
+#include <linux/types.h>
+
+#include "intel_display_core.h"
+#include "intel_display_regs.h"
+#include "intel_gvt_api.h"
+
+u32 intel_display_device_pipe_offset(struct intel_display *display, enum pipe pipe)
+{
+       return INTEL_DISPLAY_DEVICE_PIPE_OFFSET(display, pipe);
+}
+EXPORT_SYMBOL_NS_GPL(intel_display_device_pipe_offset, "I915_GVT");
+
+u32 intel_display_device_trans_offset(struct intel_display *display, enum transcoder trans)
+{
+       return INTEL_DISPLAY_DEVICE_TRANS_OFFSET(display, trans);
+}
+EXPORT_SYMBOL_NS_GPL(intel_display_device_trans_offset, "I915_GVT");
+
+u32 intel_display_device_cursor_offset(struct intel_display *display, enum pipe pipe)
+{
+       return INTEL_DISPLAY_DEVICE_CURSOR_OFFSET(display, pipe);
+}
+EXPORT_SYMBOL_NS_GPL(intel_display_device_cursor_offset, "I915_GVT");
+
+u32 intel_display_device_mmio_base(struct intel_display *display)
+{
+       return DISPLAY_MMIO_BASE(display);
+}
+EXPORT_SYMBOL_NS_GPL(intel_display_device_mmio_base, "I915_GVT");

diff --git a/drivers/gpu/drm/i915/display/intel_gvt_api.h b/drivers/gpu/drm/i915/display/intel_gvt_api.h
new file mode 100644 (file)
index 0000000..53c851c
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_gvt_api.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2025 Intel Corporation
+ */
+
+#ifndef __INTEL_GVT_API_H__
+#define __INTEL_GVT_API_H__
+
+#include <linux/types.h>
+
+enum pipe;
+enum transcoder;
+struct intel_display;
+
+u32 intel_display_device_pipe_offset(struct intel_display *display, enum pipe pipe);
+u32 intel_display_device_trans_offset(struct intel_display *display, enum transcoder trans);
+u32 intel_display_device_cursor_offset(struct intel_display *display, enum pipe pipe);
+u32 intel_display_device_mmio_base(struct intel_display *display);
+
+#endif /* __INTEL_GVT_API_H__ */