plat/arm/juno: Add support to use hw_config in BL31

To make it possible to use the hw_config device tree for dynamic
configuration in BL31 on the Arm Juno platform. A placeholder hw_config
has been added that is included in the FIP and a Juno specific BL31
setup has been added to populate fconf with the hw_config.

Juno's BL2 setup has been updated to align it with the new behavior
implemented in the Arm FVP platform, where fw_config is passed in arg1
to BL31 instead of soc_fw_config. The BL31 setup is expected to use the
fw_config passed in arg1 to find the hw_config.

Signed-off-by: Mikael Olsson <mikael.olsson@arm.com>
Change-Id: Ib3570faa6714f92ab8451e8f1e59779dcf19c0b6
diff --git a/plat/arm/board/juno/juno_bl2_setup.c b/plat/arm/board/juno/juno_bl2_setup.c
index 95ef77c..849acd6 100644
--- a/plat/arm/board/juno/juno_bl2_setup.c
+++ b/plat/arm/board/juno/juno_bl2_setup.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2017,2021, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -8,6 +8,9 @@
 
 #include <common/bl_common.h>
 #include <common/desc_image_load.h>
+#include <lib/fconf/fconf.h>
+#include <lib/fconf/fconf_dyn_cfg_getter.h>
+
 #include <plat/arm/common/plat_arm.h>
 
 #if JUNO_AARCH32_EL3_RUNTIME
@@ -30,4 +33,41 @@
 
 	return err;
 }
+
+#else
+
+/*******************************************************************************
+ * This function returns the list of executable images
+ ******************************************************************************/
+struct bl_params *plat_get_next_bl_params(void)
+{
+	struct bl_params *arm_bl_params = arm_get_next_bl_params();
+
+#if __aarch64__
+	const struct dyn_cfg_dtb_info_t *fw_config_info;
+	bl_mem_params_node_t *param_node;
+	uintptr_t fw_config_base = 0U;
+	entry_point_info_t *ep_info;
+
+	/* Get BL31 image node */
+	param_node = get_bl_mem_params_node(BL31_IMAGE_ID);
+	assert(param_node != NULL);
+
+	/* Get fw_config load address */
+	fw_config_info = FCONF_GET_PROPERTY(dyn_cfg, dtb, FW_CONFIG_ID);
+	assert(fw_config_info != NULL);
+
+	fw_config_base = fw_config_info->config_addr;
+	assert(fw_config_base != 0U);
+
+	/*
+	 * Get the entry point info of BL31 image and override
+	 * arg1 of entry point info with fw_config base address
+	 */
+	ep_info = &param_node->ep_info;
+	ep_info->args.arg1 = (uint32_t)fw_config_base;
+#endif /* __aarch64__ */
+
+	return arm_bl_params;
+}
 #endif /* JUNO_AARCH32_EL3_RUNTIME */