drm/xe/reg_sr: Save errors for kunit integration

When there's an entry that is dropped when xe_reg_sr_add(), there's
not much we can do other than reporting the error - it's for certain a
driver issue or conflicting workarounds/tunings. Save the number of
errors to be used later by kunit to report where it happens.
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://lore.kernel.org/r/20230401085151.1786204-6-lucas.demarchi@intel.comSigned-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_reg_sr.c

@@ -82,6 +82,13 @@ static bool compatible_entries(const struct xe_reg_sr_entry *e1,
 	return true;
 }
 
+static void reg_sr_inc_error(struct xe_reg_sr *sr)
+{
+#if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST)
+	sr->errors++;
+#endif
+}
+
 int xe_reg_sr_add(struct xe_reg_sr *sr, u32 reg,
 		  const struct xe_reg_sr_entry *e)
 {
@@ -119,6 +126,7 @@ int xe_reg_sr_add(struct xe_reg_sr *sr, u32 reg,
 	DRM_ERROR("Discarding save-restore reg %04lx (clear: %08x, set: %08x, masked: %s): ret=%d\n",
 		  idx, e->clr_bits, e->set_bits,
 		  str_yes_no(e->masked_reg), ret);
+	reg_sr_inc_error(sr);
 
 	return ret;
 }

drivers/gpu/drm/xe/xe_reg_sr_types.h

@@ -32,6 +32,10 @@ struct xe_reg_sr {
 	} pool;
 	struct xarray xa;
 	const char *name;
+
+#if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST)
+	unsigned int errors;
+#endif
 };
 
 #endif