drm/i915/pxp: Add GSC-CS back-end resource init and cleanup

For MTL, the PXP back-end transport uses the GSC engine to submit
HECI packets through the HW to the GSC firmware for PXP arb
session management. This submission uses a non-priveleged
batch buffer, a buffer for the command packet and of course
a context targeting the GSC-CS.

Thus for MTL, we need to allocate and free a set of execution
submission resources for the management of the arbitration session.
Lets start with the context creation first since that object and
its usage is very straight-forward. We'll add the buffer allocation
and freeing later when we introduce the gsccs' send-message function.

Do this one time allocation of gsccs specific resources in
a new gsccs source file with intel_pxp_gsccs_init / fini functions
and hook them up from the PXP front-end.
Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230511231738.1077674-2-alan.previn.teres.alexis@intel.com

drivers/gpu/drm/i915/Makefile

@@ -339,6 +339,7 @@ i915-y += \
 i915-$(CONFIG_DRM_I915_PXP) += \
 	pxp/intel_pxp_cmd.o \
 	pxp/intel_pxp_debugfs.o \
+	pxp/intel_pxp_gsccs.o \
 	pxp/intel_pxp_irq.o \
 	pxp/intel_pxp_pm.o \
 	pxp/intel_pxp_session.o

drivers/gpu/drm/i915/pxp/intel_pxp.c

@@ -12,6 +12,7 @@
 #include "i915_drv.h"
 
 #include "intel_pxp.h"
+#include "intel_pxp_gsccs.h"
 #include "intel_pxp_irq.h"
 #include "intel_pxp_session.h"
 #include "intel_pxp_tee.h"
@@ -132,6 +133,9 @@ static void pxp_init_full(struct intel_pxp *pxp)
 	if (ret)
 		return;
 
+	if (HAS_ENGINE(pxp->ctrl_gt, GSC0))
+		ret = intel_pxp_gsccs_init(pxp);
+	else
 		ret = intel_pxp_tee_component_init(pxp);
 	if (ret)
 		goto out_context;
@@ -165,9 +169,12 @@ static struct intel_gt *find_gt_for_required_protected_content(struct drm_i915_p
 	/*
 	 * For MTL onwards, PXP-controller-GT needs to have a valid GSC engine
 	 * on the media GT. NOTE: if we have a media-tile with a GSC-engine,
-	 * the VDBOX is already present so skip that check
+	 * the VDBOX is already present so skip that check. We also have to
+	 * ensure the GSC and HUC firmware are coming online
 	 */
-	if (i915->media_gt && HAS_ENGINE(i915->media_gt, GSC0))
+	if (i915->media_gt && HAS_ENGINE(i915->media_gt, GSC0) &&
+	    intel_uc_fw_is_loadable(&i915->media_gt->uc.gsc.fw) &&
+	    intel_uc_fw_is_loadable(&i915->media_gt->uc.huc.fw))
 		return i915->media_gt;
 
 	/*
@@ -207,7 +214,9 @@ int intel_pxp_init(struct drm_i915_private *i915)
 	if (!i915->pxp)
 		return -ENOMEM;
 
+	/* init common info used by all feature-mode usages*/
 	i915->pxp->ctrl_gt = gt;
+	mutex_init(&i915->pxp->tee_mutex);
 
 	/*
 	 * If full PXP feature is not available but HuC is loaded by GSC on pre-MTL
@@ -229,6 +238,9 @@ void intel_pxp_fini(struct drm_i915_private *i915)
 
 	i915->pxp->arb_is_valid = false;
 
+	if (HAS_ENGINE(i915->pxp->ctrl_gt, GSC0))
+		intel_pxp_gsccs_fini(i915->pxp);
+	else
 		intel_pxp_tee_component_fini(i915->pxp);
 
 	destroy_vcs_context(i915->pxp);

drivers/gpu/drm/i915/pxp/intel_pxp_gsccs.c

+// SPDX-License-Identifier: MIT
+/*
+ * Copyright(c) 2023 Intel Corporation.
+ */
+
+#include "gem/i915_gem_internal.h"
+
+#include "gt/intel_context.h"
+
+#include "i915_drv.h"
+#include "intel_pxp_cmd_interface_43.h"
+#include "intel_pxp_gsccs.h"
+#include "intel_pxp_types.h"
+
+static void
+gsccs_destroy_execution_resource(struct intel_pxp *pxp)
+{
+	struct gsccs_session_resources *exec_res = &pxp->gsccs_res;
+
+	if (exec_res->ce)
+		intel_context_put(exec_res->ce);
+
+	memset(exec_res, 0, sizeof(*exec_res));
+}
+
+static int
+gsccs_allocate_execution_resource(struct intel_pxp *pxp)
+{
+	struct intel_gt *gt = pxp->ctrl_gt;
+	struct gsccs_session_resources *exec_res = &pxp->gsccs_res;
+	struct intel_engine_cs *engine = gt->engine[GSC0];
+	struct intel_context *ce;
+
+	/*
+	 * First, ensure the GSC engine is present.
+	 * NOTE: Backend would only be called with the correct gt.
+	 */
+	if (!engine)
+		return -ENODEV;
+
+	/* Finally, create an intel_context to be used during the submission */
+	ce = intel_context_create(engine);
+	if (IS_ERR(ce)) {
+		drm_err(&gt->i915->drm, "Failed creating gsccs backend ctx\n");
+		return PTR_ERR(ce);
+	}
+
+	i915_vm_put(ce->vm);
+	ce->vm = i915_vm_get(pxp->ctrl_gt->vm);
+	exec_res->ce = ce;
+
+	return 0;
+}
+
+void intel_pxp_gsccs_fini(struct intel_pxp *pxp)
+{
+	gsccs_destroy_execution_resource(pxp);
+}
+
+int intel_pxp_gsccs_init(struct intel_pxp *pxp)
+{
+	return gsccs_allocate_execution_resource(pxp);
+}

drivers/gpu/drm/i915/pxp/intel_pxp_gsccs.h

+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright(c) 2022, Intel Corporation. All rights reserved.
+ */
+
+#ifndef __INTEL_PXP_GSCCS_H__
+#define __INTEL_PXP_GSCCS_H__
+
+#include <linux/types.h>
+
+struct intel_pxp;
+
+#ifdef CONFIG_DRM_I915_PXP
+void intel_pxp_gsccs_fini(struct intel_pxp *pxp);
+int intel_pxp_gsccs_init(struct intel_pxp *pxp);
+
+#else
+static inline void intel_pxp_gsccs_fini(struct intel_pxp *pxp)
+{
+}
+
+static inline int intel_pxp_gsccs_init(struct intel_pxp *pxp)
+{
+	return 0;
+}
+
+#endif
+
+#endif /*__INTEL_PXP_GSCCS_H__ */

drivers/gpu/drm/i915/pxp/intel_pxp_tee.c

@@ -284,8 +284,6 @@ int intel_pxp_tee_component_init(struct intel_pxp *pxp)
 	struct intel_gt *gt = pxp->ctrl_gt;
 	struct drm_i915_private *i915 = gt->i915;
 
-	mutex_init(&pxp->tee_mutex);
-
 	ret = alloc_streaming_command(pxp);
 	if (ret)
 		return ret;

drivers/gpu/drm/i915/pxp/intel_pxp_types.h

@@ -26,6 +26,14 @@ struct intel_pxp {
 	 */
 	struct intel_gt *ctrl_gt;
 
+	/**
+	 * @gsccs_res: resources for request submission for platforms that have a GSC engine.
+	 */
+	struct gsccs_session_resources {
+		u64 host_session_handle; /* used by firmware to link commands to sessions */
+		struct intel_context *ce; /* context for gsc command submission */
+	} gsccs_res;
+
 	/**
 	 * @pxp_component: i915_pxp_component struct of the bound mei_pxp
 	 * module. Only set and cleared inside component bind/unbind functions,