drm/i915/gsc: skip irq initialization if using polling

Some platforms require the host to poll on the
GSC registers instead of relaying on the interrupts.
For those platforms, irq initialization should be skipped
Signed-off-by: Vitaly Lubart <vitaly.lubart@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220907215113.1596567-2-tomas.winkler@intel.comSigned-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drivers/gpu/drm/i915/gt/intel_gsc.c

@@ -40,6 +40,7 @@ struct gsc_def {
 	const char *name;
 	unsigned long bar;
 	size_t bar_size;
+	bool use_polling;
 };
 
 /* gsc resources and definitions (HECI1 and HECI2) */
@@ -117,6 +118,10 @@ static void gsc_init_one(struct drm_i915_private *i915,
 		return;
 	}
 
+	/* skip irq initialization */
+	if (def->use_polling)
+		goto add_device;
+
 	intf->irq = irq_alloc_desc(0);
 	if (intf->irq < 0) {
 		drm_err(&i915->drm, "gsc irq error %d\n", intf->irq);
@@ -129,6 +134,7 @@ static void gsc_init_one(struct drm_i915_private *i915,
 		goto fail;
 	}
 
+add_device:
 	adev = kzalloc(sizeof(*adev), GFP_KERNEL);
 	if (!adev)
 		goto fail;
@@ -182,10 +188,8 @@ static void gsc_irq_handler(struct intel_gt *gt, unsigned int intf_id)
 		return;
 	}
 
-	if (gt->gsc.intf[intf_id].irq < 0) {
-		drm_err_ratelimited(&gt->i915->drm, "GSC irq: irq not set");
+	if (gt->gsc.intf[intf_id].irq < 0)
 		return;
-	}
 
 	ret = generic_handle_irq(gt->gsc.intf[intf_id].irq);
 	if (ret)