drm/i915/display: add intel_display_snapshot abstraction

The error state capture still handles display info at a too detailed
level. Start abstracting the whole display snapshot capture and printing
at a higher level. Move overlay to display snapshot first.

Use the same nomenclature and style as in xe devcoredump, in preparation
for perhaps some day bolting the snapshots there as well.

v3: Fix build harder for CONFIG_DRM_I915_CAPTURE_ERROR=n

v2: Fix build for CONFIG_DRM_I915_CAPTURE_ERROR=n (kernel test robot)

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ba6a36759600c2d35405c41a0fc9d69f676df77d.1726151571.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/Makefile

@@ -242,6 +242,7 @@ i915-y += \
 	display/intel_display_power_well.o \
 	display/intel_display_reset.o \
 	display/intel_display_rps.o \
+	display/intel_display_snapshot.o \
 	display/intel_display_wa.o \
 	display/intel_dmc.o \
 	display/intel_dmc_wl.o \

drivers/gpu/drm/i915/display/intel_display_snapshot.c

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: MIT
+/* Copyright © 2024 Intel Corporation */
+
+#include <linux/slab.h>
+
+#include "intel_display_snapshot.h"
+#include "intel_overlay.h"
+
+struct intel_display_snapshot {
+	struct intel_overlay_snapshot *overlay;
+};
+
+struct intel_display_snapshot *intel_display_snapshot_capture(struct intel_display *display)
+{
+	struct intel_display_snapshot *snapshot;
+
+	snapshot = kzalloc(sizeof(*snapshot), GFP_ATOMIC);
+	if (!snapshot)
+		return NULL;
+
+	snapshot->overlay = intel_overlay_snapshot_capture(display);
+
+	return snapshot;
+}
+
+void intel_display_snapshot_print(const struct intel_display_snapshot *snapshot,
+				  struct drm_printer *p)
+{
+	if (!snapshot)
+		return;
+
+	intel_overlay_snapshot_print(snapshot->overlay, p);
+}
+
+void intel_display_snapshot_free(struct intel_display_snapshot *snapshot)
+{
+	if (!snapshot)
+		return;
+
+	kfree(snapshot->overlay);
+	kfree(snapshot);
+}

drivers/gpu/drm/i915/display/intel_display_snapshot.h

@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: MIT */
+/* Copyright © 2024 Intel Corporation */
+
+#ifndef __INTEL_DISPLAY_SNAPSHOT_H__
+#define __INTEL_DISPLAY_SNAPSHOT_H__
+
+struct drm_printer;
+struct intel_display;
+struct intel_display_snapshot;
+
+struct intel_display_snapshot *intel_display_snapshot_capture(struct intel_display *display);
+void intel_display_snapshot_print(const struct intel_display_snapshot *snapshot,
+				  struct drm_printer *p);
+void intel_display_snapshot_free(struct intel_display_snapshot *snapshot);
+
+#endif /* __INTEL_DISPLAY_SNAPSHOT_H__ */

drivers/gpu/drm/i915/display/intel_overlay.c

@@ -1457,18 +1457,19 @@ void intel_overlay_cleanup(struct drm_i915_private *dev_priv)
 
 #if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR)
 
-struct intel_overlay_error_state {
+struct intel_overlay_snapshot {
 	struct overlay_registers regs;
 	unsigned long base;
 	u32 dovsta;
 	u32 isr;
 };
 
-struct intel_overlay_error_state *
-intel_overlay_capture_error_state(struct drm_i915_private *dev_priv)
+struct intel_overlay_snapshot *
+intel_overlay_snapshot_capture(struct intel_display *display)
 {
+	struct drm_i915_private *dev_priv = to_i915(display->drm);
 	struct intel_overlay *overlay = dev_priv->display.overlay;
-	struct intel_overlay_error_state *error;
+	struct intel_overlay_snapshot *error;
 
 	if (!overlay || !overlay->active)
 		return NULL;
@@ -1487,9 +1488,12 @@ intel_overlay_capture_error_state(struct drm_i915_private *dev_priv)
 }
 
 void
-intel_overlay_print_error_state(struct drm_printer *p,
-				struct intel_overlay_error_state *error)
+intel_overlay_snapshot_print(const struct intel_overlay_snapshot *error,
+			     struct drm_printer *p)
 {
+	if (!error)
+		return;
+
 	drm_printf(p, "Overlay, status: 0x%08x, interrupt: 0x%08x\n",
 		   error->dovsta, error->isr);
 	drm_printf(p, "  Register file at 0x%08lx:\n", error->base);

drivers/gpu/drm/i915/display/intel_overlay.h

@@ -6,12 +6,15 @@
 #ifndef __INTEL_OVERLAY_H__
 #define __INTEL_OVERLAY_H__
 
+#include <linux/types.h>
+
 struct drm_device;
 struct drm_file;
 struct drm_i915_private;
 struct drm_printer;
+struct intel_display;
 struct intel_overlay;
-struct intel_overlay_error_state;
+struct intel_overlay_snapshot;
 
 #ifdef I915
 void intel_overlay_setup(struct drm_i915_private *dev_priv);
@@ -22,10 +25,6 @@ int intel_overlay_put_image_ioctl(struct drm_device *dev, void *data,
 int intel_overlay_attrs_ioctl(struct drm_device *dev, void *data,
 			      struct drm_file *file_priv);
 void intel_overlay_reset(struct drm_i915_private *dev_priv);
-struct intel_overlay_error_state *
-intel_overlay_capture_error_state(struct drm_i915_private *dev_priv);
-void intel_overlay_print_error_state(struct drm_printer *p,
-				     struct intel_overlay_error_state *error);
 #else
 static inline void intel_overlay_setup(struct drm_i915_private *dev_priv)
 {
@@ -50,13 +49,21 @@ static inline int intel_overlay_attrs_ioctl(struct drm_device *dev, void *data,
 static inline void intel_overlay_reset(struct drm_i915_private *dev_priv)
 {
 }
-static inline struct intel_overlay_error_state *
-intel_overlay_capture_error_state(struct drm_i915_private *dev_priv)
+#endif
+
+#if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR) && defined(I915)
+struct intel_overlay_snapshot *
+intel_overlay_snapshot_capture(struct intel_display *display);
+void intel_overlay_snapshot_print(const struct intel_overlay_snapshot *error,
+				  struct drm_printer *p);
+#else
+static inline struct intel_overlay_snapshot *
+intel_overlay_snapshot_capture(struct intel_display *display)
 {
 	return NULL;
 }
-static inline void intel_overlay_print_error_state(struct drm_printer *p,
-						   struct intel_overlay_error_state *error)
+static inline void intel_overlay_snapshot_print(const struct intel_overlay_snapshot *error,
+						struct drm_printer *p)
 {
 }
 #endif

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -40,8 +40,8 @@
 #include <drm/drm_cache.h>
 #include <drm/drm_print.h>
 
+#include "display/intel_display_snapshot.h"
 #include "display/intel_dmc.h"
-#include "display/intel_overlay.h"
 
 #include "gem/i915_gem_context.h"
 #include "gem/i915_gem_lmem.h"
@@ -905,11 +905,10 @@ static void __err_print_to_sgl(struct drm_i915_error_state_buf *m,
 		err_print_gt_info(m, error->gt);
 	}
 
-	if (error->overlay)
-		intel_overlay_print_error_state(&p, error->overlay);
-
 	err_print_capabilities(m, error);
 	err_print_params(m, &error->params);
+
+	intel_display_snapshot_print(error->display_snapshot, &p);
 }
 
 static int err_print_to_sgl(struct i915_gpu_coredump *error)
@@ -1077,7 +1076,7 @@ void __i915_gpu_coredump_free(struct kref *error_ref)
 		cleanup_gt(gt);
 	}
 
-	kfree(error->overlay);
+	intel_display_snapshot_free(error->display_snapshot);
 
 	cleanup_params(error);
 
@@ -2097,6 +2096,7 @@ static struct i915_gpu_coredump *
 __i915_gpu_coredump(struct intel_gt *gt, intel_engine_mask_t engine_mask, u32 dump_flags)
 {
 	struct drm_i915_private *i915 = gt->i915;
+	struct intel_display *display = &i915->display;
 	struct i915_gpu_coredump *error;
 
 	/* Check if GPU capture has been disabled */
@@ -2138,7 +2138,7 @@ __i915_gpu_coredump(struct intel_gt *gt, intel_engine_mask_t engine_mask, u32 du
 		error->simulated |= error->gt->simulated;
 	}
 
-	error->overlay = intel_overlay_capture_error_state(i915);
+	error->display_snapshot = intel_display_snapshot_capture(display);
 
 	return error;
 }

drivers/gpu/drm/i915/i915_gpu_error.h

@@ -31,7 +31,7 @@
 struct drm_i915_private;
 struct i915_vma_compress;
 struct intel_engine_capture_vma;
-struct intel_overlay_error_state;
+struct intel_display_snapshot;
 
 struct i915_vma_coredump {
 	struct i915_vma_coredump *next;
@@ -218,9 +218,9 @@ struct i915_gpu_coredump {
 	struct i915_params params;
 	struct intel_display_params display_params;
 
-	struct intel_overlay_error_state *overlay;
-
 	struct scatterlist *sgl, *fit;
+
+	struct intel_display_snapshot *display_snapshot;
 };
 
 struct i915_gpu_error {