drm/i915/guc: Introduce buffer based cmd transport

Buffer based command transport can replace MMIO based mechanism.
It may be used to perform host-2-guc and guc-to-host communication.

Portions of this patch are based on work by:
 Michel Thierry <michel.thierry@intel.com>
 Robert Beckett <robert.beckett@intel.com>
 Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

v2: use gem_object_pin_map (Chris)
    don't use DEBUG_RATELIMITED (Chris)
    don't track action stats (Chris)
    simplify next fence (Chris)
    use READ_ONCE (Chris)
    move blob allocation to new function (Chris)

v3: use static owner id (Daniele)
v4: but keep channel initialization generic (Daniele)
    and introduce owner_sub_id (Daniele)

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170526111326.87280-3-michal.wajdeczko@intel.com

1 files changed, 86 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_guc_ct.h b/drivers/gpu/drm/i915/intel_guc_ct.h
new file mode 100644
index 000000000000..6d97f36fcc62
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_guc_ct.h
@@ -0,0 +1,86 @@
+/*
+ * Copyright © 2016-2017 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef _INTEL_GUC_CT_H_
+#define _INTEL_GUC_CT_H_
+
+struct intel_guc;
+struct i915_vma;
+
+#include "intel_guc_fwif.h"
+
+/**
+ * DOC: Command Transport (CT).
+ *
+ * Buffer based command transport is a replacement for MMIO based mechanism.
+ * It can be used to perform both host-2-guc and guc-to-host communication.
+ */
+
+/** Represents single command transport buffer.
+ *
+ * A single command transport buffer consists of two parts, the header
+ * record (command transport buffer descriptor) and the actual buffer which
+ * holds the commands.
+ *
+ * @desc: pointer to the buffer descriptor
+ * @cmds: pointer to the commands buffer
+ */
+struct intel_guc_ct_buffer {
+	struct guc_ct_buffer_desc *desc;
+	u32 *cmds;
+};
+
+/** Represents pair of command transport buffers.
+ *
+ * Buffers go in pairs to allow bi-directional communication.
+ * To simplify the code we place both of them in the same vma.
+ * Buffers from the same pair must share unique owner id.
+ *
+ * @vma: pointer to the vma with pair of CT buffers
+ * @ctbs: buffers for sending(0) and receiving(1) commands
+ * @owner: unique identifier
+ * @next_fence: fence to be used with next send command
+ */
+struct intel_guc_ct_channel {
+	struct i915_vma *vma;
+	struct intel_guc_ct_buffer ctbs[2];
+	u32 owner;
+	u32 next_fence;
+};
+
+/** Holds all command transport channels.
+ *
+ * @host_channel: main channel used by the host
+ */
+struct intel_guc_ct {
+	struct intel_guc_ct_channel host_channel;
+	/* other channels are tbd */
+};
+
+void intel_guc_ct_init_early(struct intel_guc_ct *ct);
+
+/* XXX: move to intel_uc.h ? don't fit there either */
+int intel_guc_enable_ct(struct intel_guc *guc);
+void intel_guc_disable_ct(struct intel_guc *guc);
+
+#endif /* _INTEL_GUC_CT_H_ */