diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 7b05fb8..16dccf5 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -58,6 +58,7 @@ i915-y += i915_cmd_parser.o \
 
 # general-purpose microcontroller (GuC) support
 i915-y += intel_uc.o \
+	  intel_guc_ct.o \
 	  intel_guc_log.o \
 	  intel_guc_loader.o \
 	  intel_huc.o \
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 72fb47a..71f7915 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -869,6 +869,7 @@ static int i915_driver_init_early(struct drm_i915_private *dev_priv,
 	i915_workqueues_cleanup(dev_priv);
 err_engines:
 	i915_engines_cleanup(dev_priv);
+	intel_uc_cleanup(dev_priv);
 	return ret;
 }
 
@@ -883,6 +884,7 @@ static void i915_driver_cleanup_early(struct drm_i915_private *dev_priv)
 	intel_irq_fini(dev_priv);
 	i915_workqueues_cleanup(dev_priv);
 	i915_engines_cleanup(dev_priv);
+	intel_uc_cleanup(dev_priv);
 }
 
 static int i915_mmio_setup(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index ff3574a..ec2d45f 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -712,6 +712,7 @@ struct intel_csr {
 	func(has_gmbus_irq); \
 	func(has_gmch_display); \
 	func(has_guc); \
+	func(has_guc_ct); \
 	func(has_hotplug); \
 	func(has_l3_dpf); \
 	func(has_llc); \
@@ -2831,6 +2832,7 @@ intel_info(const struct drm_i915_private *dev_priv)
  * properties, so we have separate macros to test them.
  */
 #define HAS_GUC(dev_priv)	((dev_priv)->info.has_guc)
+#define HAS_GUC_CT(dev_priv)	((dev_priv)->info.has_guc_ct)
 #define HAS_GUC_UCODE(dev_priv)	(HAS_GUC(dev_priv))
 #define HAS_GUC_SCHED(dev_priv)	(HAS_GUC(dev_priv))
 #define HAS_HUC_UCODE(dev_priv)	(HAS_GUC(dev_priv))
diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index f9d6607..cd4a0d9 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -86,6 +86,10 @@
 
 #define ptr_offset(ptr, member) offsetof(typeof(*(ptr)), member)
 
+#define arr_offset(arr, index, member) ({				\
+	(index) * sizeof((arr)[0]) + ptr_offset(&(arr)[0], member);	\
+})
+
 #define fetch_and_zero(ptr) ({						\
 	typeof(*ptr) __T = *(ptr);					\
 	*(ptr) = (typeof(*ptr))0;					\
diff --git a/drivers/gpu/drm/i915/intel_guc_ct.c b/drivers/gpu/drm/i915/intel_guc_ct.c
new file mode 100644
index 0000000..6eb46e0
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_guc_ct.c
@@ -0,0 +1,440 @@
+/*
+ * 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.
+ */
+
+#include "i915_drv.h"
+#include "intel_guc_ct.h"
+
+static inline const char *guc_ct_buffer_type_to_str(u32 type)
+{
+	switch (type) {
+	case INTEL_GUC_CT_BUFFER_TYPE_SEND:
+		return "SEND";
+	case INTEL_GUC_CT_BUFFER_TYPE_RECV:
+		return "RECV";
+	default:
+		return "<invalid>";
+	}
+}
+
+static void guc_ct_buffer_desc_init(struct guc_ct_buffer_desc *desc,
+				    u32 cmds_addr, u32 size, u32 owner)
+{
+	DRM_DEBUG_DRIVER("CT: desc %p init addr=%#x size=%u owner=%u\n",
+			 desc, cmds_addr, size, owner);
+	memset(desc, 0, sizeof(*desc));
+	desc->addr = cmds_addr;
+	desc->size = size;
+	desc->owner = owner;
+}
+
+static void guc_ct_buffer_desc_reset(struct guc_ct_buffer_desc *desc)
+{
+	DRM_DEBUG_DRIVER("CT: desc %p reset head=%u tail=%u\n",
+			 desc, desc->head, desc->tail);
+	desc->head = 0;
+	desc->tail = 0;
+	desc->is_in_error = 0;
+}
+
+static int guc_action_register_ct_buffer(struct intel_guc *guc,
+					 u32 desc_addr,
+					 u32 type)
+{
+	u32 action[] = {
+		INTEL_GUC_ACTION_REGISTER_COMMAND_TRANSPORT_BUFFER,
+		desc_addr,
+		sizeof(struct guc_ct_buffer_desc),
+		type
+	};
+	int err;
+
+	/* Can't use generic send(), CT registration must go over MMIO */
+	err = intel_guc_send_mmio(guc, action, ARRAY_SIZE(action));
+	if (err)
+		DRM_ERROR("CT: register %s buffer failed; err=%d\n",
+			  guc_ct_buffer_type_to_str(type), err);
+	return err;
+}
+
+static int guc_action_deregister_ct_buffer(struct intel_guc *guc,
+					   u32 owner,
+					   u32 type)
+{
+	u32 action[] = {
+		INTEL_GUC_ACTION_DEREGISTER_COMMAND_TRANSPORT_BUFFER,
+		owner,
+		type
+	};
+	int err;
+
+	/* Can't use generic send(), CT deregistration must go over MMIO */
+	err = intel_guc_send_mmio(guc, action, ARRAY_SIZE(action));
+	if (err)
+		DRM_ERROR("CT: deregister %s buffer failed; err=%d\n",
+			  guc_ct_buffer_type_to_str(type), err);
+	return err;
+}
+
+static bool ctch_is_open(struct intel_guc_ct_channel *ctch)
+{
+	return ctch->vma != NULL;
+}
+
+static int ctch_open(struct intel_guc *guc,
+		     struct intel_guc_ct_channel *ctch)
+{
+	struct i915_vma *vma;
+	struct __aligned(PAGE_SIZE/2) __packed {
+		struct guc_ct_buffer_desc desc __aligned(4);
+		u32 cmds[] __aligned(4);
+	} (*blob)[2];
+	u32 base;
+	int err;
+	int i;
+
+	/* We allocate 1 page to hold both buffers and both descriptors.
+	 * Each message can use a maximum of 32 dwords and we don't expect to
+	 * have more than 1 in flight at any time, so we have enough space.
+	 * Some logic further ahead will rely on the fact that there is only 1
+	 * page and that it is always mapped, so if the size is changed the
+	 * other code will need updating as well.
+	 */
+	BUILD_BUG_ON(sizeof(*blob) != PAGE_SIZE);
+	BUILD_BUG_ON(sizeof(*blob[0]) != PAGE_SIZE/2);
+	BUILD_BUG_ON(ARRAY_SIZE(*blob) != 2);
+	BUILD_BUG_ON(ARRAY_SIZE(*blob) != ARRAY_SIZE(ctch->ctbs));
+
+	DRM_DEBUG_DRIVER("CT: reopen=%s\n", yesno(ctch_is_open(ctch)));
+
+	if (!ctch->vma) {
+		/* allocate vma */
+		vma = intel_guc_allocate_vma(guc, sizeof(*blob));
+		if (IS_ERR(vma))
+			return PTR_ERR(vma);
+		ctch->vma = vma;
+
+		/* get unique owner id */
+		err = ida_simple_get(&guc->ct.owner_ida,
+				     0, INTEL_GUC_CT_MAX_CHANNELS,
+				     GFP_KERNEL);
+		if (err < 0)
+			goto err_vma;
+		ctch->owner = err;
+		DRM_DEBUG_DRIVER("CT: owner=%d\n", ctch->owner);
+
+		/* kmap first page */
+		blob = kmap(i915_vma_first_page(vma));
+
+		base = guc_ggtt_offset(ctch->vma);
+		DRM_DEBUG_DRIVER("CT: vma base=%#x\n", base);
+
+		/* initialize descriptors */
+		for (i = 0; i < ARRAY_SIZE(*blob); i++) {
+			struct guc_ct_buffer_desc *desc = &(*blob)[i].desc;
+
+			guc_ct_buffer_desc_init(desc,
+					base + arr_offset(*blob, i, cmds),
+					sizeof((*blob)[0]) -
+					ptr_offset(&(*blob)[0], cmds),
+					ctch->owner);
+
+			ctch->ctbs[i].desc = desc;
+			ctch->ctbs[i].cmds = (*blob)[i].cmds;
+		}
+
+	} else {
+		/* vma is already allocated and kmap'ed */
+		base = guc_ggtt_offset(ctch->vma);
+
+		/* reset descriptors */
+		for (i = 0; i < ARRAY_SIZE(ctch->ctbs); i++) {
+			guc_ct_buffer_desc_reset(ctch->ctbs[i].desc);
+		}
+	}
+
+
+	/* register buffers, recv first */
+	err = guc_action_register_ct_buffer(guc,
+					    base +
+					    arr_offset(*blob, 1, desc),
+					    INTEL_GUC_CT_BUFFER_TYPE_RECV);
+	if (unlikely(err))
+		goto err_kunmap;
+
+	err = guc_action_register_ct_buffer(guc,
+					    base +
+					    arr_offset(*blob, 0, desc),
+					    INTEL_GUC_CT_BUFFER_TYPE_SEND);
+	if (unlikely(err))
+		goto err_deregister;
+
+	return 0;
+
+err_deregister:
+	guc_action_deregister_ct_buffer(guc,
+					ctch->owner,
+					INTEL_GUC_CT_BUFFER_TYPE_RECV);
+err_kunmap:
+	kunmap(i915_vma_first_page(ctch->vma));
+	ida_simple_remove(&guc->ct.owner_ida, ctch->owner);
+err_vma:
+	i915_vma_unpin_and_release(&ctch->vma);
+	return err;
+}
+
+static void ctch_close(struct intel_guc *guc,
+		       struct intel_guc_ct_channel *ctch)
+{
+	GEM_BUG_ON(!ctch_is_open(ctch));
+
+	guc_action_deregister_ct_buffer(guc,
+					ctch->owner,
+					INTEL_GUC_CT_BUFFER_TYPE_SEND);
+	guc_action_deregister_ct_buffer(guc,
+					ctch->owner,
+					INTEL_GUC_CT_BUFFER_TYPE_RECV);
+
+	ida_simple_remove(&guc->ct.owner_ida, ctch->owner);
+
+	/* Unmap the page we mapped in the _open() */
+	kunmap(i915_vma_first_page(ctch->vma));
+
+	/* Now we can safely release the vma */
+	i915_vma_unpin_and_release(&ctch->vma);
+}
+
+static u32 ctch_get_next_fence(struct intel_guc_ct_channel *ctch)
+{
+	u32 fence;
+
+	fence = ctch->next_fence++;
+	if (fence == 0)
+		fence = ctch->next_fence++;
+
+	return fence;
+}
+
+static int ctb_write(struct intel_guc_ct_buffer *ctb,
+		     const u32 *action,
+		     u32 len /* in dwords */,
+		     u32 fence)
+{
+	struct guc_ct_buffer_desc *desc = ctb->desc;
+	u32 head = desc->head / 4;	/* in dwords */
+	u32 tail = desc->tail / 4;	/* in dwords */
+	u32 size = desc->size / 4;	/* in dwords */
+	u32 used;			/* in dwords */
+	u32 header;
+	u32 *cmds = ctb->cmds;
+	unsigned int i;
+
+	GEM_BUG_ON(desc->size % 4);
+	GEM_BUG_ON(desc->head % 4);
+	GEM_BUG_ON(desc->tail % 4);
+	GEM_BUG_ON(tail >= size);
+
+	/*
+	 * tail == head condition indicates empty. GuC FW does not support
+	 * using up the entire buffer to get tail == head meaning full.
+	 */
+	if (tail < head)
+		used = (size - head) + tail;
+	else
+		used = tail - head;
+
+	/* make sure there is a space including extra dw for the fence */
+	if (unlikely(used + len + 1 >= size))
+		return -ENOSPC;
+
+	/* Write the message. The format is the following:
+	 * DW0: header (including action code)
+	 * DW1: fence
+	 * DW2+: action data
+	 */
+	header = (len << GUC_CT_MSG_LEN_SHIFT) |
+		 (GUC_CT_MSG_WRITE_FENCE_TO_DESC) |
+		 (action[0] << GUC_CT_MSG_ACTION_SHIFT);
+
+	cmds[tail] = header;
+	tail = (tail + 1) % size;
+
+	cmds[tail] = fence;
+	tail = (tail + 1) % size;
+
+	for (i = 1; i < len; i++) {
+		cmds[tail] = action[i];
+		tail = (tail + 1) % size;
+	}
+
+	/* now update desc tail (back in bytes) */
+	desc->tail = tail * 4;
+	GEM_BUG_ON(desc->tail > desc->size);
+
+	return 0;
+}
+
+/* Wait for the response from the GuC.
+ * @fence:	response fence
+ * @status:	placeholder for status
+ * return:	0 response received (status is valid)
+ *		-ETIMEDOUT no response within hardcoded timeout
+ *		-EPROTO no response, ct buffer was in error
+ */
+static int wait_for_response(struct guc_ct_buffer_desc *desc,
+			     u32 fence,
+			     u32 *status)
+{
+	int err;
+
+	/*
+	 * Fast commands should complete in less than 10us, so sample quickly
+	 * up to that length of time, then switch to a slower sleep-wait loop.
+	 * No GuC command should ever take longer than 10ms.
+	 */
+#define done (desc->fence == fence)
+	err = wait_for_us(done, 10);
+	if (err)
+		err = wait_for(done, 10);
+#undef done
+
+	if (unlikely(err)) {
+		DRM_ERROR("CT: fence %u failed; reported fence=%u\n",
+			  fence, desc->fence);
+
+		if (WARN_ON(desc->is_in_error)) {
+			/* Something went wrong with the messaging, try to reset
+			 * the buffer and hope for the best
+			 */
+			guc_ct_buffer_desc_reset(desc);
+			err = -EPROTO;
+		}
+	}
+
+	*status = desc->status;
+	return err;
+}
+
+static int ctch_send(struct intel_guc *guc,
+		     struct intel_guc_ct_channel *ctch,
+		     const u32 *action,
+		     u32 len,
+		     u32 *status)
+{
+	struct intel_guc_ct_buffer *ctb = &ctch->ctbs[0];
+	struct guc_ct_buffer_desc *desc = ctb->desc;
+	u32 fence;
+	int err;
+
+	DRM_DEBUG_DRIVER_RATELIMITED("CT: sending %*phn\n", len*4, action);
+
+	GEM_BUG_ON(!ctch_is_open(ctch));
+	GEM_BUG_ON(!len);
+	GEM_BUG_ON(len & ~GUC_CT_MSG_LEN_MASK);
+
+	fence = ctch_get_next_fence(ctch);
+	err = ctb_write(ctb, action, len, fence);
+	if (unlikely(err))
+		return err;
+
+	intel_guc_notify(guc);
+
+	err = wait_for_response(desc, fence, status);
+	if (unlikely(err))
+		return err;
+	if (*status != INTEL_GUC_STATUS_SUCCESS)
+		return -EIO;
+	return 0;
+}
+
+/*
+ * Command Transport (CT) buffer based GuC send function.
+ */
+static int intel_guc_send_ct(struct intel_guc *guc, const u32 *action, u32 len)
+{
+	struct intel_guc_ct_channel *ctch = &guc->ct.channel;
+	u32 status = ~0; /* undefined */
+	int err;
+
+	mutex_lock(&guc->send_mutex);
+	guc->action_count += 1;
+	guc->action_cmd = action[0];
+
+	err = ctch_send(guc, ctch, action, len, &status);
+	if (unlikely(err)) {
+		DRM_ERROR("CT: send action %#X failed; err=%d status=%#X\n",
+			  action[0], err, status);
+		guc->action_fail += 1;
+		guc->action_err = err;
+	}
+
+	guc->action_status = status;
+	mutex_unlock(&guc->send_mutex);
+	return err;
+}
+
+/**
+ * Enable buffer based command transport
+ * Shall only be called for platforms with HAS_GUC_CT.
+ * @guc:	the guc
+ * return:	0 on success
+ *		non-zero on failure
+ */
+int intel_guc_enable_ct(struct intel_guc *guc)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+	struct intel_guc_ct_channel *ctch = &guc->ct.channel;
+	int err;
+
+	GEM_BUG_ON(!HAS_GUC_CT(dev_priv));
+
+	err = ctch_open(guc, ctch);
+	if (unlikely(err))
+		return err;
+
+	/* Switch into cmd transport buffer based send() */
+	guc->send = intel_guc_send_ct;
+	DRM_INFO("CT: %s\n", enableddisabled(true));
+	return 0;
+}
+
+/**
+ * Disable buffer based command transport.
+ * Shall only be called for platforms with HAS_GUC_CT.
+ * @guc: the guc
+ */
+void intel_guc_disable_ct(struct intel_guc *guc)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+	struct intel_guc_ct_channel *ctch = &guc->ct.channel;
+
+	GEM_BUG_ON(!HAS_GUC_CT(dev_priv));
+
+	if (!ctch_is_open(ctch))
+		return;
+
+	ctch_close(guc, ctch);
+
+	/* Disable send */
+	guc->send = intel_guc_send_nop;
+	DRM_INFO("CT: %s\n", enableddisabled(false));
+}
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 0000000..dbbe9f6
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_guc_ct.h
@@ -0,0 +1,92 @@
+/*
+ * 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]; /* 0=SEND 1=RECV */
+	u32 owner;
+	u32 next_fence;
+};
+
+/* */
+struct intel_guc_ct {
+	struct ida owner_ida;
+	struct intel_guc_ct_channel channel;
+};
+#define INTEL_GUC_CT_MAX_CHANNELS	1
+
+static inline void intel_guc_ct_init_early(struct intel_guc_ct *ct)
+{
+	ida_init(&ct->owner_ida);
+}
+
+static inline void intel_guc_ct_cleanup(struct intel_guc_ct *ct)
+{
+	ida_destroy(&ct->owner_ida);
+}
+
+/* XXX: move to intel_uc.h ? but it doesn'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_ */
diff --git a/drivers/gpu/drm/i915/intel_guc_fwif.h b/drivers/gpu/drm/i915/intel_guc_fwif.h
index 6156845..d90e3a2 100644
--- a/drivers/gpu/drm/i915/intel_guc_fwif.h
+++ b/drivers/gpu/drm/i915/intel_guc_fwif.h
@@ -331,6 +331,46 @@ struct guc_stage_desc {
 	u64 desc_private;
 } __packed;
 
+/*
+ * Describes single command transport buffer.
+ * Used by both guc-master and clients.
+ */
+struct guc_ct_buffer_desc {
+	u32 addr;		/* gfx address */
+	u64 vaddr;		/* virtual address */
+	u32 size;		/* size in bytes */
+	u32 head;		/* offset updated by GuC*/
+	u32 tail;		/* offset updated by owner */
+	u32 is_in_error;	/* error indicator */
+	u32 fence;		/* fence updated by GuC */
+	u32 status;		/* status updated by GuC */
+	u32 owner;		/* id assigned by owner */
+	u32 reserved[6];
+} __packed;
+
+/* Type of command transport buffer */
+#define INTEL_GUC_CT_BUFFER_TYPE_SEND	0x0u
+#define INTEL_GUC_CT_BUFFER_TYPE_RECV	0x1u
+
+/*
+ * Definition of the command transport message header (DW0)
+ *
+ * bit[4..0]	message len (in dwords)
+ * bit[7..5]	reserved
+ * bit[8]	write fence to desc
+ * bit[9]	write status to H2G buff
+ * bit[10]	send status (via G2H)
+ * bit[15..11]	reserved
+ * bit[31..16]	action code
+ */
+#define GUC_CT_MSG_LEN_SHIFT			0
+#define GUC_CT_MSG_LEN_MASK			0x1F
+#define GUC_CT_MSG_WRITE_FENCE_TO_DESC		(1 << 8)
+#define GUC_CT_MSG_WRITE_STATUS_TO_BUFF		(1 << 9)
+#define GUC_CT_MSG_SEND_STATUS			(1 << 10)
+#define GUC_CT_MSG_ACTION_SHIFT			16
+#define GUC_CT_MSG_ACTION_MASK			0xFFFF
+
 #define GUC_FORCEWAKE_RENDER	(1 << 0)
 #define GUC_FORCEWAKE_MEDIA	(1 << 1)
 
@@ -515,6 +555,8 @@ enum intel_guc_action {
 	INTEL_GUC_ACTION_EXIT_S_STATE = 0x502,
 	INTEL_GUC_ACTION_SLPC_REQUEST = 0x3003,
 	INTEL_GUC_ACTION_AUTHENTICATE_HUC = 0x4000,
+	INTEL_GUC_ACTION_REGISTER_COMMAND_TRANSPORT_BUFFER = 0x4505,
+	INTEL_GUC_ACTION_DEREGISTER_COMMAND_TRANSPORT_BUFFER = 0x4506,
 	INTEL_GUC_ACTION_UK_LOG_ENABLE_LOGGING = 0x0E000,
 	INTEL_GUC_ACTION_LIMIT
 };
diff --git a/drivers/gpu/drm/i915/intel_uc.c b/drivers/gpu/drm/i915/intel_uc.c
index 940a3c9..c26f075 100644
--- a/drivers/gpu/drm/i915/intel_uc.c
+++ b/drivers/gpu/drm/i915/intel_uc.c
@@ -108,6 +108,14 @@ void intel_uc_init_early(struct drm_i915_private *dev_priv)
 	mutex_init(&guc->send_mutex);
 	guc->send = intel_guc_send_nop;
 	guc->notify = guc_write_irq_trigger;
+	intel_guc_ct_init_early(&guc->ct);
+}
+
+void intel_uc_cleanup(struct drm_i915_private *dev_priv)
+{
+	struct intel_guc *guc = &dev_priv->guc;
+
+	intel_guc_ct_cleanup(&guc->ct);
 }
 
 static void fetch_uc_fw(struct drm_i915_private *dev_priv,
@@ -288,14 +296,24 @@ static void guc_init_send_regs(struct intel_guc *guc)
 
 static int guc_enable_communication(struct intel_guc *guc)
 {
-	/* XXX: placeholder for alternate setup */
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+
 	guc_init_send_regs(guc);
+
+	if (HAS_GUC_CT(dev_priv))
+		return intel_guc_enable_ct(guc);
+
 	guc->send = intel_guc_send_mmio;
 	return 0;
 }
 
 static void guc_disable_communication(struct intel_guc *guc)
 {
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+
+	if (HAS_GUC_CT(dev_priv))
+		intel_guc_disable_ct(guc);
+
 	guc->send = intel_guc_send_nop;
 }
 
@@ -440,6 +458,11 @@ int intel_guc_send_mmio(struct intel_guc *guc, const u32 *action, u32 len)
 	GEM_BUG_ON(!len);
 	GEM_BUG_ON(len > guc->send_regs.count);
 
+	/* If CT is available, we expect to use MMIO only during init/fini */
+	GEM_BUG_ON(HAS_GUC_CT(dev_priv) &&
+		*action != INTEL_GUC_ACTION_REGISTER_COMMAND_TRANSPORT_BUFFER &&
+		*action != INTEL_GUC_ACTION_DEREGISTER_COMMAND_TRANSPORT_BUFFER);
+
 	mutex_lock(&guc->send_mutex);
 	intel_uncore_forcewake_get(dev_priv, guc->send_regs.fw_domains);
 
diff --git a/drivers/gpu/drm/i915/intel_uc.h b/drivers/gpu/drm/i915/intel_uc.h
index 7618b71..003ef95 100644
--- a/drivers/gpu/drm/i915/intel_uc.h
+++ b/drivers/gpu/drm/i915/intel_uc.h
@@ -27,7 +27,7 @@
 #include "intel_guc_fwif.h"
 #include "i915_guc_reg.h"
 #include "intel_ringbuffer.h"
-
+#include "intel_guc_ct.h"
 #include "i915_vma.h"
 
 struct drm_i915_gem_request;
@@ -181,6 +181,7 @@ struct intel_guc_log {
 struct intel_guc {
 	struct intel_uc_fw fw;
 	struct intel_guc_log log;
+	struct intel_guc_ct ct;
 
 	/* intel_guc_recv interrupt related state */
 	bool interrupts_enabled;
@@ -232,6 +233,7 @@ struct intel_huc {
 /* intel_uc.c */
 void intel_uc_sanitize_options(struct drm_i915_private *dev_priv);
 void intel_uc_init_early(struct drm_i915_private *dev_priv);
+void intel_uc_cleanup(struct drm_i915_private *dev_priv);
 void intel_uc_init_fw(struct drm_i915_private *dev_priv);
 void intel_uc_fini_fw(struct drm_i915_private *dev_priv);
 int intel_uc_init_hw(struct drm_i915_private *dev_priv);
