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_bl31_setup.c b/plat/arm/board/juno/juno_bl31_setup.c
new file mode 100644
index 0000000..7a0a6d9
--- /dev/null
+++ b/plat/arm/board/juno/juno_bl31_setup.c
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2021, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <common/debug.h>
+#include <lib/fconf/fconf.h>
+#include <lib/fconf/fconf_dyn_cfg_getter.h>
+
+#include <plat/arm/common/plat_arm.h>
+
+void __init bl31_early_platform_setup2(u_register_t arg0,
+		u_register_t arg1, u_register_t arg2, u_register_t arg3)
+{
+	const struct dyn_cfg_dtb_info_t *soc_fw_config_info;
+
+	INFO("BL31 FCONF: FW_CONFIG address = %lx\n", (uintptr_t)arg1);
+
+	/* Fill the properties struct with the info from the config dtb */
+	fconf_populate("FW_CONFIG", arg1);
+
+	soc_fw_config_info = FCONF_GET_PROPERTY(dyn_cfg, dtb, SOC_FW_CONFIG_ID);
+	if (soc_fw_config_info != NULL) {
+		arg1 = soc_fw_config_info->config_addr;
+	}
+
+	arm_bl31_early_platform_setup((void *)arg0, arg1, arg2, (void *)arg3);
+
+	/*
+	 * Initialize Interconnect for this cluster during cold boot.
+	 * No need for locks as no other CPU is active.
+	 */
+	plat_arm_interconnect_init();
+
+	/*
+	 * Enable Interconnect coherency for the primary CPU's cluster.
+	 * Earlier bootloader stages might already do this (e.g. Trusted
+	 * Firmware's BL1 does it) but we can't assume so. There is no harm in
+	 * executing this code twice anyway.
+	 * Platform specific PSCI code will enable coherency for other
+	 * clusters.
+	 */
+	plat_arm_interconnect_enter_coherency();
+}
+
+void __init bl31_plat_arch_setup(void)
+{
+	arm_bl31_plat_arch_setup();
+
+	/* HW_CONFIG was also loaded by BL2 */
+	const struct dyn_cfg_dtb_info_t *hw_config_info;
+
+	hw_config_info = FCONF_GET_PROPERTY(dyn_cfg, dtb, HW_CONFIG_ID);
+	assert(hw_config_info != NULL);
+
+	fconf_populate("HW_CONFIG", hw_config_info->config_addr);
+}