drm/xe/hdcp: Enable HDCP for XE

Enable HDCP for Xe by defining functions which take care of
interaction of HDCP as a client with the GSC CS interface.
Add intel_hdcp_gsc_message to Makefile and add corresponding
changes to xe_hdcp_gsc.c to make it build.

--v2
-add kfree at appropriate place [Daniele]
-remove useless define [Daniele]
-move host session logic to xe_gsc_submit.c [Daniele]
-call xe_gsc_check_and_update_pending directly in an if condition
[Daniele]
-use xe_device instead of drm_i915_private [Daniele]

--v3
-use xe prefix for newly exposed function [Daniele]
-remove client specific defines from intel_gsc_mtl_header [Daniele]
-add missing kfree() [Daniele]
-have NULL check for hdcp_message in finish function [Daniele]
-dont have too many variable declarations in the same line [Daniele]

--v4
-don't point the hdcp_message structure in xe_device to anything
until it properly gets initialized [Daniele]

--v5
-Squash commits for buildability

--v6
-Order includes alphabetically [Lucas]

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy@intel.com>
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240306024247.1857881-6-suraj.kandpal@intel.com

drivers/gpu/drm/xe/Makefile

@@ -257,6 +257,7 @@ xe-$(CONFIG_DRM_XE_DISPLAY) += \
 	i915-display/intel_global_state.o \
 	i915-display/intel_gmbus.o \
 	i915-display/intel_hdcp.o \
+	i915-display/intel_hdcp_gsc_message.o \
 	i915-display/intel_hdmi.o \
 	i915-display/intel_hotplug.o \
 	i915-display/intel_hotplug_irq.o \

drivers/gpu/drm/xe/display/xe_hdcp_gsc.c

@@ -4,15 +4,32 @@
  */
 
 #include <drm/drm_print.h>
+#include <drm/i915_hdcp_interface.h>
+#include <linux/delay.h>
 
+#include "abi/gsc_command_header_abi.h"
 #include "intel_hdcp_gsc.h"
-#include "xe_device_types.h"
+#include "intel_hdcp_gsc_message.h"
+#include "xe_bo.h"
 #include "xe_device.h"
-#include "xe_gt.h"
+#include "xe_device_types.h"
 #include "xe_gsc_proxy.h"
+#include "xe_gsc_submit.h"
+#include "xe_gt.h"
+#include "xe_map.h"
 #include "xe_pm.h"
 #include "xe_uc_fw.h"
 
+#define HECI_MEADDRESS_HDCP 18
+
+struct intel_hdcp_gsc_message {
+	struct xe_bo *hdcp_bo;
+	u64 hdcp_cmd_in;
+	u64 hdcp_cmd_out;
+};
+
+#define HDCP_GSC_HEADER_SIZE sizeof(struct intel_gsc_mtl_header)
+
 bool intel_hdcp_gsc_cs_required(struct xe_device *xe)
 {
 	return true;
@@ -44,19 +61,194 @@ out:
 	return ret;
 }
 
+/*This function helps allocate memory for the command that we will send to gsc cs */
+static int intel_hdcp_gsc_initialize_message(struct xe_device *xe,
+					     struct intel_hdcp_gsc_message *hdcp_message)
+{
+	struct xe_bo *bo = NULL;
+	u64 cmd_in, cmd_out;
+	int ret = 0;
+
+	/* allocate object of two page for HDCP command memory and store it */
+	xe_device_mem_access_get(xe);
+	bo = xe_bo_create_pin_map(xe, xe_device_get_root_tile(xe), NULL, PAGE_SIZE * 2,
+				  ttm_bo_type_kernel,
+				  XE_BO_CREATE_SYSTEM_BIT |
+				  XE_BO_CREATE_GGTT_BIT);
+
+	if (IS_ERR(bo)) {
+		drm_err(&xe->drm, "Failed to allocate bo for HDCP streaming command!\n");
+		ret = PTR_ERR(bo);
+		goto out;
+	}
+
+	cmd_in = xe_bo_ggtt_addr(bo);
+	cmd_out = cmd_in + PAGE_SIZE;
+	xe_map_memset(xe, &bo->vmap, 0, 0, bo->size);
+
+	hdcp_message->hdcp_bo = bo;
+	hdcp_message->hdcp_cmd_in = cmd_in;
+	hdcp_message->hdcp_cmd_out = cmd_out;
+out:
+	xe_device_mem_access_put(xe);
+	return ret;
+}
+
+static int intel_hdcp_gsc_hdcp2_init(struct xe_device *xe)
+{
+	struct intel_hdcp_gsc_message *hdcp_message;
+	int ret;
+
+	hdcp_message = kzalloc(sizeof(*hdcp_message), GFP_KERNEL);
+
+	if (!hdcp_message)
+		return -ENOMEM;
+
+	/*
+	 * NOTE: No need to lock the comp mutex here as it is already
+	 * going to be taken before this function called
+	 */
+	ret = intel_hdcp_gsc_initialize_message(xe, hdcp_message);
+	if (ret) {
+		drm_err(&xe->drm, "Could not initialize hdcp_message\n");
+		kfree(hdcp_message);
+		return ret;
+	}
+
+	xe->display.hdcp.hdcp_message = hdcp_message;
+	return ret;
+}
+
+static const struct i915_hdcp_ops gsc_hdcp_ops = {
+	.initiate_hdcp2_session = intel_hdcp_gsc_initiate_session,
+	.verify_receiver_cert_prepare_km =
+				intel_hdcp_gsc_verify_receiver_cert_prepare_km,
+	.verify_hprime = intel_hdcp_gsc_verify_hprime,
+	.store_pairing_info = intel_hdcp_gsc_store_pairing_info,
+	.initiate_locality_check = intel_hdcp_gsc_initiate_locality_check,
+	.verify_lprime = intel_hdcp_gsc_verify_lprime,
+	.get_session_key = intel_hdcp_gsc_get_session_key,
+	.repeater_check_flow_prepare_ack =
+				intel_hdcp_gsc_repeater_check_flow_prepare_ack,
+	.verify_mprime = intel_hdcp_gsc_verify_mprime,
+	.enable_hdcp_authentication = intel_hdcp_gsc_enable_authentication,
+	.close_hdcp_session = intel_hdcp_gsc_close_session,
+};
+
 int intel_hdcp_gsc_init(struct xe_device *xe)
 {
-	drm_dbg_kms(&xe->drm, "HDCP support not yet implemented\n");
-	return -ENODEV;
+	struct i915_hdcp_arbiter *data;
+	int ret;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	mutex_lock(&xe->display.hdcp.hdcp_mutex);
+	xe->display.hdcp.arbiter = data;
+	xe->display.hdcp.arbiter->hdcp_dev = xe->drm.dev;
+	xe->display.hdcp.arbiter->ops = &gsc_hdcp_ops;
+	ret = intel_hdcp_gsc_hdcp2_init(xe);
+	if (ret)
+		kfree(data);
+
+	mutex_unlock(&xe->display.hdcp.hdcp_mutex);
+
+	return ret;
 }
 
 void intel_hdcp_gsc_fini(struct xe_device *xe)
 {
+	struct intel_hdcp_gsc_message *hdcp_message =
+					xe->display.hdcp.hdcp_message;
+
+	if (!hdcp_message)
+		return;
+
+	xe_bo_unpin_map_no_vm(hdcp_message->hdcp_bo);
+	kfree(hdcp_message);
+}
+
+static int xe_gsc_send_sync(struct xe_device *xe,
+			    struct intel_hdcp_gsc_message *hdcp_message,
+			    u32 msg_size_in, u32 msg_size_out,
+			    u32 addr_out_off)
+{
+	struct xe_gt *gt = hdcp_message->hdcp_bo->tile->media_gt;
+	struct iosys_map *map = &hdcp_message->hdcp_bo->vmap;
+	struct xe_gsc *gsc = &gt->uc.gsc;
+	int ret;
+
+	ret = xe_gsc_pkt_submit_kernel(gsc, hdcp_message->hdcp_cmd_in, msg_size_in,
+				       hdcp_message->hdcp_cmd_out, msg_size_out);
+	if (ret) {
+		drm_err(&xe->drm, "failed to send gsc HDCP msg (%d)\n", ret);
+		return ret;
+	}
+
+	if (xe_gsc_check_and_update_pending(xe, map, 0, map, addr_out_off))
+		return -EAGAIN;
+
+	ret = xe_gsc_read_out_header(xe, map, addr_out_off,
+				     sizeof(struct hdcp_cmd_header), NULL);
+
+	return ret;
 }
 
 ssize_t intel_hdcp_gsc_msg_send(struct xe_device *xe, u8 *msg_in,
 				size_t msg_in_len, u8 *msg_out,
 				size_t msg_out_len)
 {
-	return -ENODEV;
+	const size_t max_msg_size = PAGE_SIZE - HDCP_GSC_HEADER_SIZE;
+	struct intel_hdcp_gsc_message *hdcp_message;
+	u64 host_session_id;
+	u32 msg_size_in, msg_size_out;
+	u32 addr_out_off, addr_in_wr_off = 0;
+	int ret, tries = 0;
+
+	if (msg_in_len > max_msg_size || msg_out_len > max_msg_size) {
+		ret = -ENOSPC;
+		goto out;
+	}
+
+	msg_size_in = msg_in_len + HDCP_GSC_HEADER_SIZE;
+	msg_size_out = msg_out_len + HDCP_GSC_HEADER_SIZE;
+	hdcp_message = xe->display.hdcp.hdcp_message;
+	addr_out_off = PAGE_SIZE;
+
+	host_session_id = xe_gsc_create_host_session_id();
+	xe_device_mem_access_get(xe);
+	addr_in_wr_off = xe_gsc_emit_header(xe, &hdcp_message->hdcp_bo->vmap,
+					    addr_in_wr_off, HECI_MEADDRESS_HDCP,
+					    host_session_id, msg_in_len);
+	xe_map_memcpy_to(xe, &hdcp_message->hdcp_bo->vmap, addr_in_wr_off,
+			 msg_in, msg_in_len);
+	/*
+	 * Keep sending request in case the pending bit is set no need to add
+	 * message handle as we are using same address hence loc. of header is
+	 * same and it will contain the message handle. we will send the message
+	 * 20 times each message 50 ms apart
+	 */
+	do {
+		ret = xe_gsc_send_sync(xe, hdcp_message, msg_size_in, msg_size_out,
+				       addr_out_off);
+
+		/* Only try again if gsc says so */
+		if (ret != -EAGAIN)
+			break;
+
+		msleep(50);
+
+	} while (++tries < 20);
+
+	if (ret)
+		goto out;
+
+	xe_map_memcpy_from(xe, msg_out, &hdcp_message->hdcp_bo->vmap,
+			   addr_out_off + HDCP_GSC_HEADER_SIZE,
+			   msg_out_len);
+
+out:
+	xe_device_mem_access_put(xe);
+	return ret;
 }

drivers/gpu/drm/xe/xe_gsc_submit.c

@@ -40,6 +40,21 @@ gsc_to_gt(struct xe_gsc *gsc)
 	return container_of(gsc, struct xe_gt, uc.gsc);
 }
 
+/**
+ * xe_gsc_get_host_session_id - Creates a random 64 bit host_session id with
+ * bits 56-63 masked.
+ *
+ * Returns: random host_session_id which can be used to send messages to gsc cs
+ */
+u64 xe_gsc_create_host_session_id(void)
+{
+	u64 host_session_id;
+
+	get_random_bytes(&host_session_id, sizeof(u64));
+	host_session_id &= ~HOST_SESSION_CLIENT_MASK;
+	return host_session_id;
+}
+
 /**
  * xe_gsc_emit_header - write the MTL GSC header in memory
  * @xe: the Xe device

drivers/gpu/drm/xe/xe_gsc_submit.h

@@ -28,4 +28,5 @@ int xe_gsc_read_out_header(struct xe_device *xe,
 int xe_gsc_pkt_submit_kernel(struct xe_gsc *gsc, u64 addr_in, u32 size_in,
 			     u64 addr_out, u32 size_out);
 
+u64 xe_gsc_create_host_session_id(void);
 #endif