Tegra: enable SDEI handling

This patch enables SDEI support for all Tegra platforms, with
the following configuration settings.

* SGI 8 as the source IRQ
* Special Private Event 0
* Three private, dynamic events
* Three shared, dynamic events
* Twelve general purpose explicit events

Verified using TFTF SDEI test suite.

******************************* Summary *******************************
 Test suite 'SDEI'                                               Passed
 =================================
 Tests Skipped : 0
 Tests Passed  : 5
 Tests Failed  : 0
 Tests Crashed : 0
 Total tests   : 5
 =================================

Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
Change-Id: I1922069931a7876a4594e53260ee09f2e4f09390
diff --git a/plat/nvidia/tegra/common/tegra_ehf.c b/plat/nvidia/tegra/common/tegra_ehf.c
new file mode 100644
index 0000000..ea6e443
--- /dev/null
+++ b/plat/nvidia/tegra/common/tegra_ehf.c
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2020, NVIDIA Corporation. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <platform_def.h>
+
+#include <bl31/ehf.h>
+
+/*
+ * Enumeration of priority levels on Tegra platforms.
+ */
+ehf_pri_desc_t tegra_exceptions[] = {
+	/* Watchdog priority */
+	EHF_PRI_DESC(PLAT_PRI_BITS, PLAT_TEGRA_WDT_PRIO),
+
+#if SDEI_SUPPORT
+	/* Critical priority SDEI */
+	EHF_PRI_DESC(PLAT_PRI_BITS, PLAT_SDEI_CRITICAL_PRI),
+
+	/* Normal priority SDEI */
+	EHF_PRI_DESC(PLAT_PRI_BITS, PLAT_SDEI_NORMAL_PRI),
+#endif
+};
+
+/* Plug in Tegra exceptions to Exception Handling Framework. */
+EHF_REGISTER_PRIORITIES(tegra_exceptions, ARRAY_SIZE(tegra_exceptions), PLAT_PRI_BITS);