drm/i915/pxp: add huc authentication and loading command

Add support for loading HuC via a pxp stream command.

V4:
1. Remove unnecessary include in intel_pxp_huc.h (Jani)
2. Adjust copyright year to 2022

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Vitaly Lubart <vitaly.lubart@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220928004145.745803-10-daniele.ceraolospurio@intel.com

drivers/gpu/drm/i915/Makefile

@@ -312,7 +312,8 @@ i915-y += i915_perf.o
 # Protected execution platform (PXP) support. Base support is required for HuC
 i915-y += \
 	pxp/intel_pxp.o \
-	pxp/intel_pxp_tee.o
+	pxp/intel_pxp_tee.o \
+	pxp/intel_pxp_huc.o
 
 i915-$(CONFIG_DRM_I915_PXP) += \
 	pxp/intel_pxp_cmd.o \

drivers/gpu/drm/i915/pxp/intel_pxp_huc.c

@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright(c) 2021-2022, Intel Corporation. All rights reserved.
+ */
+
+#include "drm/i915_drm.h"
+#include "i915_drv.h"
+
+#include "gem/i915_gem_region.h"
+#include "gt/intel_gt.h"
+
+#include "intel_pxp.h"
+#include "intel_pxp_huc.h"
+#include "intel_pxp_tee.h"
+#include "intel_pxp_types.h"
+#include "intel_pxp_tee_interface.h"
+
+int intel_pxp_huc_load_and_auth(struct intel_pxp *pxp)
+{
+	struct intel_gt *gt = pxp_to_gt(pxp);
+	struct intel_huc *huc = &gt->uc.huc;
+	struct pxp_tee_start_huc_auth_in huc_in = {0};
+	struct pxp_tee_start_huc_auth_out huc_out = {0};
+	dma_addr_t huc_phys_addr;
+	u8 client_id = 0;
+	u8 fence_id = 0;
+	int err;
+
+	if (!pxp->pxp_component)
+		return -ENODEV;
+
+	huc_phys_addr = i915_gem_object_get_dma_address(huc->fw.obj, 0);
+
+	/* write the PXP message into the lmem (the sg list) */
+	huc_in.header.api_version = PXP_TEE_43_APIVER;
+	huc_in.header.command_id  = PXP_TEE_43_START_HUC_AUTH;
+	huc_in.header.status      = 0;
+	huc_in.header.buffer_len  = sizeof(huc_in.huc_base_address);
+	huc_in.huc_base_address   = huc_phys_addr;
+
+	err = intel_pxp_tee_stream_message(pxp, client_id, fence_id,
+					   &huc_in, sizeof(huc_in),
+					   &huc_out, sizeof(huc_out));
+	if (err < 0) {
+		drm_err(&gt->i915->drm,
+			"Failed to send HuC load and auth command to GSC [%d]!\n",
+			err);
+		return err;
+	}
+
+	/*
+	 * HuC does sometimes survive suspend/resume (it depends on how "deep"
+	 * a sleep state the device reaches) so we can end up here on resume
+	 * with HuC already loaded, in which case the GSC will return
+	 * PXP_STATUS_OP_NOT_PERMITTED. We can therefore consider the GuC
+	 * correctly transferred in this scenario; if the same error is ever
+	 * returned with HuC not loaded we'll still catch it when we check the
+	 * authentication bit later.
+	 */
+	if (huc_out.header.status != PXP_STATUS_SUCCESS &&
+	    huc_out.header.status != PXP_STATUS_OP_NOT_PERMITTED) {
+		drm_err(&gt->i915->drm,
+			"HuC load failed with GSC error = 0x%x\n",
+			huc_out.header.status);
+		return -EPROTO;
+	}
+
+	return 0;
+}

drivers/gpu/drm/i915/pxp/intel_pxp_huc.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright(c) 2021-2022, Intel Corporation. All rights reserved.
+ */
+
+#ifndef __INTEL_PXP_HUC_H__
+#define __INTEL_PXP_HUC_H__
+
+struct intel_pxp;
+
+int intel_pxp_huc_load_and_auth(struct intel_pxp *pxp);
+
+#endif /* __INTEL_PXP_HUC_H__ */

drivers/gpu/drm/i915/pxp/intel_pxp_tee_interface.h

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT */
 /*
- * Copyright(c) 2020, Intel Corporation. All rights reserved.
+ * Copyright(c) 2020-2022, Intel Corporation. All rights reserved.
  */
 
 #ifndef __INTEL_PXP_TEE_INTERFACE_H__
@@ -9,8 +9,20 @@
 #include <linux/types.h>
 
 #define PXP_TEE_APIVER 0x40002
+#define PXP_TEE_43_APIVER 0x00040003
 #define PXP_TEE_ARB_CMDID 0x1e
 #define PXP_TEE_ARB_PROTECTION_MODE 0x2
+#define PXP_TEE_43_START_HUC_AUTH   0x0000003A
+
+/*
+ * there are a lot of status codes for PXP, but we only define the ones we
+ * actually can handle in the driver. other failure codes will be printed to
+ * error msg for debug.
+ */
+enum pxp_status {
+	PXP_STATUS_SUCCESS = 0x0,
+	PXP_STATUS_OP_NOT_PERMITTED = 0x4013
+};
 
 /* PXP TEE message header */
 struct pxp_tee_cmd_header {
@@ -33,4 +45,13 @@ struct pxp_tee_create_arb_out {
 	struct pxp_tee_cmd_header header;
 } __packed;
 
+struct pxp_tee_start_huc_auth_in {
+	struct pxp_tee_cmd_header header;
+	__le64                    huc_base_address;
+};
+
+struct pxp_tee_start_huc_auth_out {
+	struct pxp_tee_cmd_header header;
+};
+
 #endif /* __INTEL_PXP_TEE_INTERFACE_H__ */