stm32mp1: introduce shared resources support

STM32MP1 SoC includes peripheral interfaces that can be assigned to
the secure world, or that can be opened to the non-secure world.

This change introduces the basics of a driver that manages such
resources which assignation is done at run time. It currently offers
API functions that state whether a service exposed to non-secure
world has permission to access a targeted clock or reset controller.

Change-Id: Iff20028f41586bc501085488c03546ffe31046d8
Signed-off-by: Etienne Carriere <etienne.carriere@st.com>

plat/st/common/include/stm32mp_shared_resources.h

+/*
+ * Copyright (c) 2017-2020, STMicroelectronics - All Rights Reserved
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef STM32MP_SHARED_RESOURCES_H
+#define STM32MP_SHARED_RESOURCES_H
+
+#include <stdbool.h>
+
+/* Return true if @clock_id is shared by secure and non-secure worlds */
+bool stm32mp_nsec_can_access_clock(unsigned long clock_id);
+
+/* Return true if and only if @reset_id relates to a non-secure peripheral */
+bool stm32mp_nsec_can_access_reset(unsigned int reset_id);
+
+#endif /* STM32MP_SHARED_RESOURCES_H */

plat/st/stm32mp1/sp_min/sp_min-stm32mp1.mk

@@ -6,10 +6,13 @@
 
 SP_MIN_WITH_SECURE_FIQ	:=	1
 
+BL32_CFLAGS		+=	-DSTM32MP_SHARED_RESOURCES
+
 BL32_SOURCES		+=	drivers/st/etzpc/etzpc.c			\
 				plat/common/aarch32/platform_mp_stack.S		\
 				plat/st/stm32mp1/sp_min/sp_min_setup.c		\
 				plat/st/stm32mp1/stm32mp1_pm.c			\
+				plat/st/stm32mp1/stm32mp1_shared_resources.c	\
 				plat/st/stm32mp1/stm32mp1_topology.c
 
 # Generic GIC v2

plat/st/stm32mp1/stm32mp1_shared_resources.c

+/*
+ * Copyright (c) 2017-2020, STMicroelectronics - All Rights Reserved
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stm32mp_shared_resources.h>
+
+/* Currently allow full access by non-secure to platform clock services */
+bool stm32mp_nsec_can_access_clock(unsigned long clock_id)
+{
+	return true;
+}
+
+/* Currently allow full access by non-secure to platform reset services */
+bool stm32mp_nsec_can_access_reset(unsigned int reset_id)
+{
+	return true;
+}