drm/i915/pxp: allocate a vcs context for pxp usage

The context is required to send the session termination commands to the
VCS, which will be implemented in a follow-up patch. We can also use the
presence of the context as a check of pxp initialization completion.

v2: use perma-pinned context (Chris)
v3: rename pinned_context functions (Chris)
v4: split export of pinned_context functions to a separate patch (Rodrigo)
v10: remove inclusion of intel_gt_types.h from intel_pxp.h (Jani)
v13: fixed for loop pointer dereference (Vinay)

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210924191452.1539378-5-alan.previn.teres.alexis@intel.com

3 files changed, 117 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.c b/drivers/gpu/drm/i915/pxp/intel_pxp.c
new file mode 100644
index 000000000000..9258e0ddd0d5
--- /dev/null
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright(c) 2020 Intel Corporation.
+ */
+#include "intel_pxp.h"
+#include "gt/intel_context.h"
+#include "i915_drv.h"
+
+struct intel_gt *pxp_to_gt(const struct intel_pxp *pxp)
+{
+	return container_of(pxp, struct intel_gt, pxp);
+}
+
+static int create_vcs_context(struct intel_pxp *pxp)
+{
+	static struct lock_class_key pxp_lock;
+	struct intel_gt *gt = pxp_to_gt(pxp);
+	struct intel_engine_cs *engine;
+	struct intel_context *ce;
+	int i;
+
+	/*
+	 * Find the first VCS engine present. We're guaranteed there is one
+	 * if we're in this function due to the check in has_pxp
+	 */
+	for (i = 0, engine = NULL; !engine; i++)
+		engine = gt->engine_class[VIDEO_DECODE_CLASS][i];
+
+	GEM_BUG_ON(!engine || engine->class != VIDEO_DECODE_CLASS);
+
+	ce = intel_engine_create_pinned_context(engine, engine->gt->vm, SZ_4K,
+						I915_GEM_HWS_PXP_ADDR,
+						&pxp_lock, "pxp_context");
+	if (IS_ERR(ce)) {
+		drm_err(&gt->i915->drm, "failed to create VCS ctx for PXP\n");
+		return PTR_ERR(ce);
+	}
+
+	pxp->ce = ce;
+
+	return 0;
+}
+
+static void destroy_vcs_context(struct intel_pxp *pxp)
+{
+	intel_engine_destroy_pinned_context(fetch_and_zero(&pxp->ce));
+}
+
+void intel_pxp_init(struct intel_pxp *pxp)
+{
+	struct intel_gt *gt = pxp_to_gt(pxp);
+	int ret;
+
+	if (!HAS_PXP(gt->i915))
+		return;
+
+	ret = create_vcs_context(pxp);
+	if (ret)
+		return;
+
+	drm_info(&gt->i915->drm, "Protected Xe Path (PXP) protected content support initialized\n");
+}
+
+void intel_pxp_fini(struct intel_pxp *pxp)
+{
+	if (!intel_pxp_is_enabled(pxp))
+		return;
+
+	destroy_vcs_context(pxp);
+}
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.h b/drivers/gpu/drm/i915/pxp/intel_pxp.h
new file mode 100644
index 000000000000..73acd879f2fb
--- /dev/null
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright(c) 2020, Intel Corporation. All rights reserved.
+ */
+
+#ifndef __INTEL_PXP_H__
+#define __INTEL_PXP_H__
+
+#include "intel_pxp_types.h"
+
+static inline bool intel_pxp_is_enabled(const struct intel_pxp *pxp)
+{
+	return pxp->ce;
+}
+
+#ifdef CONFIG_DRM_I915_PXP
+struct intel_gt *pxp_to_gt(const struct intel_pxp *pxp);
+void intel_pxp_init(struct intel_pxp *pxp);
+void intel_pxp_fini(struct intel_pxp *pxp);
+#else
+static inline void intel_pxp_init(struct intel_pxp *pxp)
+{
+}
+
+static inline void intel_pxp_fini(struct intel_pxp *pxp)
+{
+}
+#endif
+
+#endif /* __INTEL_PXP_H__ */
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_types.h b/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
new file mode 100644
index 000000000000..db98df723dbb
--- /dev/null
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright(c) 2020, Intel Corporation. All rights reserved.
+ */
+
+#ifndef __INTEL_PXP_TYPES_H__
+#define __INTEL_PXP_TYPES_H__
+
+#include <linux/types.h>
+
+struct intel_context;
+
+struct intel_pxp {
+	struct intel_context *ce;
+};
+
+#endif /* __INTEL_PXP_TYPES_H__ */