drm/i915: use display snapshot mechanism for display irq regs

Move more display specific parts of GPU error logging behind the display
snapshot interface.

With the display register capture reduced to just one register, DERRMR,
there's quite a bit of boilerplate here. However, it's still a nice
abstraction and removes a DISPLAY_VER() usage from core i915. With this
approach, it's also easy to add to xe as needed.

v2: Remove stale comment

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/13206969df04426d290d2863dc574e22ca45193a.1744630147.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_display_irq.c b/drivers/gpu/drm/i915/display/intel_display_irq.c
index d2a35e3630b1..f5dc050a6344 100644
--- a/drivers/gpu/drm/i915/display/intel_display_irq.c
+++ b/drivers/gpu/drm/i915/display/intel_display_irq.c
@@ -2329,3 +2329,31 @@ void intel_display_irq_init(struct intel_display *display)
 
 	INIT_WORK(&display->irq.vblank_dc_work, intel_display_vblank_dc_work);
 }
+
+struct intel_display_irq_snapshot {
+	u32 derrmr;
+};
+
+struct intel_display_irq_snapshot *
+intel_display_irq_snapshot_capture(struct intel_display *display)
+{
+	struct intel_display_irq_snapshot *snapshot;
+
+	snapshot = kzalloc(sizeof(*snapshot), GFP_ATOMIC);
+	if (!snapshot)
+		return NULL;
+
+	if (DISPLAY_VER(display) >= 6 && DISPLAY_VER(display) < 20)
+		snapshot->derrmr = intel_de_read(display, DERRMR);
+
+	return snapshot;
+}
+
+void intel_display_irq_snapshot_print(const struct intel_display_irq_snapshot *snapshot,
+				      struct drm_printer *p)
+{
+	if (!snapshot)
+		return;
+
+	drm_printf(p, "DERRMR: 0x%08x\n", snapshot->derrmr);
+}