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

1 files changed, 63 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_gsccs.c b/drivers/gpu/drm/i915/pxp/intel_pxp_gsccs.c
new file mode 100644
index 000000000000..bad55719a7ac
--- /dev/null
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp_gsccs.c
@@ -0,0 +1,63 @@
+// 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);
+}