drm/i915/guc: Prepare send() function to accept bigger response

This is a preparation step for the upcoming patches.
We already can return some small data decoded from the command
status, but we will need more in the future.

v2: add explicit response buf size
v3: squash with helper patch

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180326194829.58836-4-michal.wajdeczko@intel.com

drivers/gpu/drm/i915/intel_guc.c

@@ -310,7 +310,8 @@ void intel_guc_init_params(struct intel_guc *guc)
 	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_BLITTER);
 }
 
-int intel_guc_send_nop(struct intel_guc *guc, const u32 *action, u32 len)
+int intel_guc_send_nop(struct intel_guc *guc, const u32 *action, u32 len,
+		       u32 *response_buf, u32 response_buf_size)
 {
 	WARN(1, "Unexpected send: action=%#x\n", *action);
 	return -ENODEV;
@@ -319,7 +320,8 @@ int intel_guc_send_nop(struct intel_guc *guc, const u32 *action, u32 len)
 /*
  * This function implements the MMIO based host to GuC interface.
  */
-int intel_guc_send_mmio(struct intel_guc *guc, const u32 *action, u32 len)
+int intel_guc_send_mmio(struct intel_guc *guc, const u32 *action, u32 len,
+			u32 *response_buf, u32 response_buf_size)
 {
 	struct drm_i915_private *dev_priv = guc_to_i915(guc);
 	u32 status;

drivers/gpu/drm/i915/intel_guc.h

@@ -88,7 +88,8 @@ struct intel_guc {
 	struct mutex send_mutex;
 
 	/* GuC's FW specific send function */
-	int (*send)(struct intel_guc *guc, const u32 *data, u32 len);
+	int (*send)(struct intel_guc *guc, const u32 *data, u32 len,
+		    u32 *response_buf, u32 response_buf_size);
 
 	/* GuC's FW specific notify function */
 	void (*notify)(struct intel_guc *guc);
@@ -97,7 +98,14 @@ struct intel_guc {
 static
 inline int intel_guc_send(struct intel_guc *guc, const u32 *action, u32 len)
 {
-	return guc->send(guc, action, len);
+	return guc->send(guc, action, len, NULL, 0);
+}
+
+static inline int
+intel_guc_send_and_receive(struct intel_guc *guc, const u32 *action, u32 len,
+			   u32 *response_buf, u32 response_buf_size)
+{
+	return guc->send(guc, action, len, response_buf, response_buf_size);
 }
 
 static inline void intel_guc_notify(struct intel_guc *guc)
@@ -140,8 +148,10 @@ int intel_guc_init_wq(struct intel_guc *guc);
 void intel_guc_fini_wq(struct intel_guc *guc);
 int intel_guc_init(struct intel_guc *guc);
 void intel_guc_fini(struct intel_guc *guc);
-int intel_guc_send_nop(struct intel_guc *guc, const u32 *action, u32 len);
-int intel_guc_send_mmio(struct intel_guc *guc, const u32 *action, u32 len);
+int intel_guc_send_nop(struct intel_guc *guc, const u32 *action, u32 len,
+		       u32 *response_buf, u32 response_buf_size);
+int intel_guc_send_mmio(struct intel_guc *guc, const u32 *action, u32 len,
+			u32 *response_buf, u32 response_buf_size);
 void intel_guc_to_host_event_handler(struct intel_guc *guc);
 int intel_guc_sample_forcewake(struct intel_guc *guc);
 int intel_guc_auth_huc(struct intel_guc *guc, u32 rsa_offset);

drivers/gpu/drm/i915/intel_guc_ct.c

@@ -88,7 +88,7 @@ static int guc_action_register_ct_buffer(struct intel_guc *guc,
 	int err;
 
 	/* Can't use generic send(), CT registration must go over MMIO */
-	err = intel_guc_send_mmio(guc, action, ARRAY_SIZE(action));
+	err = intel_guc_send_mmio(guc, action, ARRAY_SIZE(action), NULL, 0);
 	if (err)
 		DRM_ERROR("CT: register %s buffer failed; err=%d\n",
 			  guc_ct_buffer_type_to_str(type), err);
@@ -107,7 +107,7 @@ static int guc_action_deregister_ct_buffer(struct intel_guc *guc,
 	int err;
 
 	/* Can't use generic send(), CT deregistration must go over MMIO */
-	err = intel_guc_send_mmio(guc, action, ARRAY_SIZE(action));
+	err = intel_guc_send_mmio(guc, action, ARRAY_SIZE(action), NULL, 0);
 	if (err)
 		DRM_ERROR("CT: deregister %s buffer failed; owner=%d err=%d\n",
 			  guc_ct_buffer_type_to_str(type), owner, err);
@@ -408,7 +408,8 @@ static int ctch_send(struct intel_guc *guc,
 /*
  * Command Transport (CT) buffer based GuC send function.
  */
-static int intel_guc_send_ct(struct intel_guc *guc, const u32 *action, u32 len)
+static int intel_guc_send_ct(struct intel_guc *guc, const u32 *action, u32 len,
+			     u32 *response_buf, u32 response_buf_size)
 {
 	struct intel_guc_ct_channel *ctch = &guc->ct.host_channel;
 	u32 status = ~0; /* undefined */