Merge changes from topic "raspberry-pi-4-support" into integration

* changes:
  rpi4: Add initial documentation file
  rpi4: Add stdout-path to device tree
  rpi4: Add GIC maintenance interrupt to GIC DT node
  rpi4: Cleanup memory regions, move pens to first page
  rpi4: Reserve resident BL31 region from non-secure world
  rpi4: Amend DTB to advertise PSCI
  rpi4: Determine BL33 entry point at runtime
  rpi4: Accommodate "armstub8.bin" header at the beginning of BL31 image
  Add basic support for Raspberry Pi 4
  rpi3: Allow runtime determination of UART base clock rate
  FDT helper functions: Respect architecture in PSCI function IDs
  FDT helper functions: Add function documentation

15 files changed, 1062 insertions, 24 deletions

diff --git a/common/fdt_fixup.c b/common/fdt_fixup.c
index 8843404d..99d0eee9 100644
--- a/common/fdt_fixup.c
+++ b/common/fdt_fixup.c
@@ -29,6 +29,33 @@ static int append_psci_compatible(void *fdt, int offs, const char *str)
 	return fdt_appendprop(fdt, offs, "compatible", str, strlen(str) + 1);
 }
 
+/*
+ * Those defines are for PSCI v0.1 legacy clients, which we expect to use
+ * the same execution state (AArch32/AArch64) as TF-A.
+ * Kernels running in AArch32 on an AArch64 TF-A should use PSCI v0.2.
+ */
+#ifdef __aarch64__
+#define PSCI_CPU_SUSPEND_FNID	PSCI_CPU_SUSPEND_AARCH64
+#define PSCI_CPU_ON_FNID	PSCI_CPU_ON_AARCH64
+#else
+#define PSCI_CPU_SUSPEND_FNID	PSCI_CPU_SUSPEND_AARCH32
+#define PSCI_CPU_ON_FNID	PSCI_CPU_ON_AARCH32
+#endif
+
+/*******************************************************************************
+ * dt_add_psci_node() - Add a PSCI node into an existing device tree
+ * @fdt:	pointer to the device tree blob in memory
+ *
+ * Add a device tree node describing PSCI into the root level of an existing
+ * device tree blob in memory.
+ * This will add v0.1, v0.2 and v1.0 compatible strings and the standard
+ * function IDs for v0.1 compatibility.
+ * An existing PSCI node will not be touched, the function will return success
+ * in this case. This function will not touch the /cpus enable methods, use
+ * dt_add_psci_cpu_enable_methods() for that.
+ *
+ * Return: 0 on success, -1 otherwise.
+ ******************************************************************************/
 int dt_add_psci_node(void *fdt)
 {
 	int offs;
@@ -52,15 +79,11 @@ int dt_add_psci_node(void *fdt)
 		return -1;
 	if (fdt_setprop_string(fdt, offs, "method", "smc"))
 		return -1;
-	if (fdt_setprop_u32(fdt, offs, "cpu_suspend", PSCI_CPU_SUSPEND_AARCH64))
+	if (fdt_setprop_u32(fdt, offs, "cpu_suspend", PSCI_CPU_SUSPEND_FNID))
 		return -1;
 	if (fdt_setprop_u32(fdt, offs, "cpu_off", PSCI_CPU_OFF))
 		return -1;
-	if (fdt_setprop_u32(fdt, offs, "cpu_on", PSCI_CPU_ON_AARCH64))
-		return -1;
-	if (fdt_setprop_u32(fdt, offs, "sys_poweroff", PSCI_SYSTEM_OFF))
-		return -1;
-	if (fdt_setprop_u32(fdt, offs, "sys_reset", PSCI_SYSTEM_RESET))
+	if (fdt_setprop_u32(fdt, offs, "cpu_on", PSCI_CPU_ON_FNID))
 		return -1;
 	return 0;
 }
@@ -113,6 +136,17 @@ static int dt_update_one_cpu_node(void *fdt, int offset)
 	return offs;
 }
 
+/*******************************************************************************
+ * dt_add_psci_cpu_enable_methods() - switch CPU nodes in DT to use PSCI
+ * @fdt:	pointer to the device tree blob in memory
+ *
+ * Iterate over all CPU device tree nodes (/cpus/cpu@x) in memory to change
+ * the enable-method to PSCI. This will add the enable-method properties, if
+ * required, or will change existing properties to read "psci".
+ *
+ * Return: 0 on success, or a negative error value otherwise.
+ ******************************************************************************/
+
 int dt_add_psci_cpu_enable_methods(void *fdt)
 {
 	int offs, ret;
@@ -130,6 +164,25 @@ int dt_add_psci_cpu_enable_methods(void *fdt)
 
 #define HIGH_BITS(x) ((sizeof(x) > 4) ? ((x) >> 32) : (typeof(x))0)
 
+/*******************************************************************************
+ * fdt_add_reserved_memory() - reserve (secure) memory regions in DT
+ * @dtb:	pointer to the device tree blob in memory
+ * @node_name:	name of the subnode to be used
+ * @base:	physical base address of the reserved region
+ * @size:	size of the reserved region
+ *
+ * Add a region of memory to the /reserved-memory node in a device tree in
+ * memory, creating that node if required. Each region goes into a subnode
+ * of that node and has a @node_name, a @base address and a @size.
+ * This will prevent any device tree consumer from using that memory. It
+ * can be used to announce secure memory regions, as it adds the "no-map"
+ * property to prevent mapping and speculative operations on that region.
+ *
+ * See reserved-memory/reserved-memory.txt in the (Linux kernel) DT binding
+ * documentation for details.
+ *
+ * Return: 0 on success, a negative error value otherwise.
+ ******************************************************************************/
 int fdt_add_reserved_memory(void *dtb, const char *node_name,
 			    uintptr_t base, size_t size)
 {
diff --git a/docs/plat/rpi4.rst b/docs/plat/rpi4.rst
new file mode 100644
index 00000000..0f529c10
--- /dev/null
+++ b/docs/plat/rpi4.rst
@@ -0,0 +1,85 @@
+Raspberry Pi 4
+==============
+
+The `Raspberry Pi 4`_ is an inexpensive single-board computer that contains four
+Arm Cortex-A72 cores. Also in contrast to previous Raspberry Pi versions this
+model has a GICv2 interrupt controller.
+
+This port is a minimal port to support loading non-secure EL2 payloads such
+as a 64-bit Linux kernel. Other payloads such as U-Boot or EDK-II should work
+as well, but have not been tested at this point.
+
+**IMPORTANT NOTE**: This port isn't secure. All of the memory used is DRAM,
+which is available from both the Non-secure and Secure worlds. The SoC does
+not seem to feature a secure memory controller of any kind, so portions of
+DRAM can't be protected properly from the Non-secure world.
+
+Build Instructions
+------------------
+
+There are no real configuration options at this point, so there is only
+one universal binary (bl31.bin), which can be built with:
+
+.. code:: shell
+
+    CROSS_COMPILE=aarch64-linux-gnu- make PLAT=rpi4 DEBUG=1
+
+Copy the generated build/rpi4/debug/bl31.bin to the SD card, either
+renaming it to ``armstub8.bin`` or adding an entry starting with ``armstub=``,
+then followed by the respective file name to ``config.txt``.
+You should have AArch64 code in the file loaded as the "kernel", as BL31
+will drop into AArch64/EL2 to the respective load address.
+arm64 Linux kernels are known to work this way.
+
+Other options that should be set in ``config.txt`` to properly boot 64-bit
+kernels are:
+
+::
+
+    enable_uart=1
+    arm_64bit=1
+    enable_gic=1
+
+The BL31 code will patch the provided device tree blob in memory to advertise
+PSCI support, also will add a reserved-memory node to the DT to tell the
+non-secure payload to not touch the resident TF-A code.
+
+If you connect a serial cable between the Mini UART and your computer, and
+connect to it (for example, with ``screen /dev/ttyUSB0 115200``) you should
+see some text from BL31, followed by the output of the EL2 payload.
+The command line provided is read from the ``cmdline.txt`` file on the SD card.
+
+TF-A port design
+----------------
+
+In contrast to the existing Raspberry Pi 3 port this one here is a BL31-only
+port, also it deviates quite a lot from the RPi3 port in many other ways.
+There is not so much difference between the two models, so eventually those
+two could be (more) unified in the future.
+
+As with the previous models, the GPU and its firmware are the first entity to
+run after the SoC gets its power. The on-chip Boot ROM loads the next stage
+(bootcode.bin) from flash (EEPROM), which is again GPU code.
+This part knows how to access the MMC controller and how to parse a FAT
+filesystem, so it will load further compononents and configuration files
+from the first FAT partition on the SD card.
+
+To accommodate this existing way of configuring and setting up the board,
+we use as much of this workflow as possible.
+If bootcode.bin finds a file called ``armstub8.bin`` on the SD card or it gets
+pointed to such code by finding a ``armstub=`` key in ``config.txt``, it will
+load this file to the beginning of DRAM (address 0) and execute it in
+AArch64 EL3.
+But before doing that, it will also load a "kernel" and the device tree into
+memory. The load addresses have a default, but can also be changed by
+setting them in ``config.txt``. If the GPU firmware finds a magic value in the
+armstub image file, it will put those two load addresses in memory locations
+near the beginning of memory, where TF-A code picks them up.
+
+To keep things simple, we will just use the kernel load address as the BL33
+entry point, also put the DTB address in the x0 register, as requested by
+the arm64 Linux kernel boot protocol. This does not necessarily mean that
+the EL2 payload needs to be a Linux kernel, a bootloader or any other kernel
+would work as well, as long as it can cope with having the DT address in
+register x0. If the payload has other means of finding the device tree, it
+could ignore this address as well.
diff --git a/plat/rpi/common/include/rpi_shared.h b/plat/rpi/common/include/rpi_shared.h
index 68634389..de835716 100644
--- a/plat/rpi/common/include/rpi_shared.h
+++ b/plat/rpi/common/include/rpi_shared.h
@@ -14,7 +14,7 @@
  ******************************************************************************/
 
 /* Utility functions */
-void rpi3_console_init(void);
+void rpi3_console_init(unsigned int base_clk_rate);
 void rpi3_setup_page_tables(uintptr_t total_base, size_t total_size,
 			    uintptr_t code_start, uintptr_t code_limit,
 			    uintptr_t rodata_start, uintptr_t rodata_limit
diff --git a/plat/rpi/common/rpi3_common.c b/plat/rpi/common/rpi3_common.c
index ab63d98f..ff336942 100644
--- a/plat/rpi/common/rpi3_common.c
+++ b/plat/rpi/common/rpi3_common.c
@@ -104,14 +104,14 @@ static const mmap_region_t plat_rpi3_mmap[] = {
  ******************************************************************************/
 static console_16550_t rpi3_console;
 
-void rpi3_console_init(void)
+void rpi3_console_init(unsigned int base_clk_rate)
 {
 	int console_scope = CONSOLE_FLAG_BOOT;
 #if RPI3_RUNTIME_UART != -1
 	console_scope |= CONSOLE_FLAG_RUNTIME;
 #endif
 	int rc = console_16550_register(PLAT_RPI3_UART_BASE,
-					PLAT_RPI3_UART_CLK_IN_HZ,
+					base_clk_rate,
 					PLAT_RPI3_UART_BAUDRATE,
 					&rpi3_console);
 	if (rc == 0) {
@@ -176,18 +176,6 @@ void rpi3_setup_page_tables(uintptr_t total_base, size_t total_size,
 }
 
 /*******************************************************************************
- * Return entrypoint of BL33.
- ******************************************************************************/
-uintptr_t plat_get_ns_image_entrypoint(void)
-{
-#ifdef PRELOADED_BL33_BASE
-	return PRELOADED_BL33_BASE;
-#else
-	return PLAT_RPI3_NS_IMAGE_OFFSET;
-#endif
-}
-
-/*******************************************************************************
  * Gets SPSR for BL32 entry
  ******************************************************************************/
 uint32_t rpi3_get_spsr_for_bl32_entry(void)
diff --git a/plat/rpi/rpi3/rpi3_bl1_setup.c b/plat/rpi/rpi3/rpi3_bl1_setup.c
index 3ac30e0f..dcce76e4 100644
--- a/plat/rpi/rpi3/rpi3_bl1_setup.c
+++ b/plat/rpi/rpi3/rpi3_bl1_setup.c
@@ -35,7 +35,7 @@ void bl1_early_platform_setup(void)
 		      0x80000000);
 
 	/* Initialize the console to provide early debug support */
-	rpi3_console_init();
+	rpi3_console_init(PLAT_RPI3_UART_CLK_IN_HZ);
 
 	/* Allow BL1 to see the whole Trusted RAM */
 	bl1_tzram_layout.total_base = BL_RAM_BASE;
diff --git a/plat/rpi/rpi3/rpi3_bl2_setup.c b/plat/rpi/rpi3/rpi3_bl2_setup.c
index 991c0fcb..44827c63 100644
--- a/plat/rpi/rpi3/rpi3_bl2_setup.c
+++ b/plat/rpi/rpi3/rpi3_bl2_setup.c
@@ -62,7 +62,7 @@ void bl2_early_platform_setup2(u_register_t arg0, u_register_t arg1,
 	meminfo_t *mem_layout = (meminfo_t *) arg1;
 
 	/* Initialize the console to provide early debug support */
-	rpi3_console_init();
+	rpi3_console_init(PLAT_RPI3_UART_CLK_IN_HZ);
 
 	/* Enable arch timer */
 	generic_delay_timer_init();
diff --git a/plat/rpi/rpi3/rpi3_bl31_setup.c b/plat/rpi/rpi3/rpi3_bl31_setup.c
index a9efc52b..24a56139 100644
--- a/plat/rpi/rpi3/rpi3_bl31_setup.c
+++ b/plat/rpi/rpi3/rpi3_bl31_setup.c
@@ -48,6 +48,18 @@ entry_point_info_t *bl31_plat_get_next_image_ep_info(uint32_t type)
 }
 
 /*******************************************************************************
+ * Return entrypoint of BL33.
+ ******************************************************************************/
+uintptr_t plat_get_ns_image_entrypoint(void)
+{
+#ifdef PRELOADED_BL33_BASE
+	return PRELOADED_BL33_BASE;
+#else
+	return PLAT_RPI3_NS_IMAGE_OFFSET;
+#endif
+}
+
+/*******************************************************************************
  * Perform any BL31 early platform setup. Here is an opportunity to copy
  * parameters passed by the calling EL (S-EL1 in BL2 & EL3 in BL1) before
  * they are lost (potentially). This needs to be done before the MMU is
@@ -60,7 +72,7 @@ void bl31_early_platform_setup2(u_register_t arg0, u_register_t arg1,
 
 {
 	/* Initialize the console to provide early debug support */
-	rpi3_console_init();
+	rpi3_console_init(PLAT_RPI3_UART_CLK_IN_HZ);
 
 	/*
 	 * In debug builds, a special value is passed in 'arg1' to verify
diff --git a/plat/rpi/rpi4/aarch64/armstub8_header.S b/plat/rpi/rpi4/aarch64/armstub8_header.S
new file mode 100644
index 00000000..246358d0
--- /dev/null
+++ b/plat/rpi/rpi4/aarch64/armstub8_header.S
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+/*
+ * armstub8.bin header to let the GPU firmware recognise this code.
+ * It will then write the load address of the kernel image and the DT
+ * after the header magic in RAM, so we can read those addresses at runtime.
+ */
+
+.text
+	b	armstub8_end
+
+.global stub_magic
+.global dtb_ptr32
+.global kernel_entry32
+
+.org 0xf0
+armstub8:
+stub_magic:
+	.word 0x5afe570b
+stub_version:
+	.word 0
+dtb_ptr32:
+	.word 0x0
+kernel_entry32:
+	.word 0x0
+
+/*
+ * Technically an offset of 0x100 would suffice, but the follow-up code
+ * (bl31_entrypoint.S at BL31_BASE) needs to be page aligned, so pad here
+ * till the end of the first 4K page.
+ */
+.org 0x1000
+armstub8_end:
diff --git a/plat/rpi/rpi4/aarch64/plat_helpers.S b/plat/rpi/rpi4/aarch64/plat_helpers.S
new file mode 100644
index 00000000..46073b79
--- /dev/null
+++ b/plat/rpi/rpi4/aarch64/plat_helpers.S
@@ -0,0 +1,187 @@
+/*
+ * Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <assert_macros.S>
+#include <platform_def.h>
+#include <cortex_a72.h>
+
+#include "../include/rpi_hw.h"
+
+	.globl	plat_crash_console_flush
+	.globl	plat_crash_console_init
+	.globl	plat_crash_console_putc
+	.globl	platform_mem_init
+	.globl	plat_get_my_entrypoint
+	.globl	plat_is_my_cpu_primary
+	.globl	plat_my_core_pos
+	.globl	plat_reset_handler
+	.globl	plat_rpi3_calc_core_pos
+	.globl	plat_secondary_cold_boot_setup
+
+	/* -----------------------------------------------------
+	 *  unsigned int plat_my_core_pos(void)
+	 *
+	 *  This function uses the plat_rpi3_calc_core_pos()
+	 *  definition to get the index of the calling CPU.
+	 * -----------------------------------------------------
+	 */
+func plat_my_core_pos
+	mrs	x0, mpidr_el1
+	b	plat_rpi3_calc_core_pos
+endfunc plat_my_core_pos
+
+	/* -----------------------------------------------------
+	 *  unsigned int plat_rpi3_calc_core_pos(u_register_t mpidr);
+	 *
+	 *  CorePos = (ClusterId * 4) + CoreId
+	 * -----------------------------------------------------
+	 */
+func plat_rpi3_calc_core_pos
+	and	x1, x0, #MPIDR_CPU_MASK
+	and	x0, x0, #MPIDR_CLUSTER_MASK
+	add	x0, x1, x0, LSR #6
+	ret
+endfunc plat_rpi3_calc_core_pos
+
+	/* -----------------------------------------------------
+	 * unsigned int plat_is_my_cpu_primary (void);
+	 *
+	 * Find out whether the current cpu is the primary
+	 * cpu.
+	 * -----------------------------------------------------
+	 */
+func plat_is_my_cpu_primary
+	mrs	x0, mpidr_el1
+	and	x0, x0, #(MPIDR_CLUSTER_MASK | MPIDR_CPU_MASK)
+	cmp	x0, #RPI4_PRIMARY_CPU
+	cset	w0, eq
+	ret
+endfunc plat_is_my_cpu_primary
+
+	/* -----------------------------------------------------
+	 * void plat_secondary_cold_boot_setup (void);
+	 *
+	 * This function performs any platform specific actions
+	 * needed for a secondary cpu after a cold reset e.g
+	 * mark the cpu's presence, mechanism to place it in a
+	 * holding pen etc.
+	 * -----------------------------------------------------
+	 */
+func plat_secondary_cold_boot_setup
+	/* Calculate address of our hold entry */
+	bl	plat_my_core_pos
+	lsl	x0, x0, #3
+	mov_imm	x2, PLAT_RPI3_TM_HOLD_BASE
+	add	x0, x0, x2
+
+	/*
+	 * This code runs way before requesting the warmboot of this core,
+	 * so it is possible to clear the mailbox before getting a request
+	 * to boot.
+	 */
+	mov	x1, PLAT_RPI3_TM_HOLD_STATE_WAIT
+	str	x1,[x0]
+
+	/* Wait until we have a go */
+poll_mailbox:
+	wfe
+	ldr	x1, [x0]
+	cmp	x1, PLAT_RPI3_TM_HOLD_STATE_GO
+	bne	poll_mailbox
+
+	/* Jump to the provided entrypoint */
+	mov_imm	x0, PLAT_RPI3_TM_ENTRYPOINT
+	ldr	x1, [x0]
+	br	x1
+endfunc plat_secondary_cold_boot_setup
+
+	/* ---------------------------------------------------------------------
+	 * uintptr_t plat_get_my_entrypoint (void);
+	 *
+	 * Main job of this routine is to distinguish between a cold and a warm
+	 * boot.
+	 *
+	 * This functions returns:
+	 *  - 0 for a cold boot.
+	 *  - Any other value for a warm boot.
+	 * ---------------------------------------------------------------------
+	 */
+func plat_get_my_entrypoint
+	/* TODO: support warm boot */
+	mov	x0, #0
+	ret
+endfunc plat_get_my_entrypoint
+
+	/* ---------------------------------------------
+	 * void platform_mem_init (void);
+	 *
+	 * No need to carry out any memory initialization.
+	 * ---------------------------------------------
+	 */
+func platform_mem_init
+	ret
+endfunc platform_mem_init
+
+	/* ---------------------------------------------
+	 * int plat_crash_console_init(void)
+	 * Function to initialize the crash console
+	 * without a C Runtime to print crash report.
+	 * Clobber list : x0 - x3
+	 * ---------------------------------------------
+	 */
+func plat_crash_console_init
+	mov_imm	x0, PLAT_RPI3_UART_BASE
+	mov_imm	x1, PLAT_RPI4_VPU_CLK_RATE
+	mov_imm	x2, PLAT_RPI3_UART_BAUDRATE
+	b	console_16550_core_init
+endfunc plat_crash_console_init
+
+	/* ---------------------------------------------
+	 * int plat_crash_console_putc(int c)
+	 * Function to print a character on the crash
+	 * console without a C Runtime.
+	 * Clobber list : x1, x2
+	 * ---------------------------------------------
+	 */
+func plat_crash_console_putc
+	mov_imm	x1, PLAT_RPI3_UART_BASE
+	b	console_16550_core_putc
+endfunc plat_crash_console_putc
+
+	/* ---------------------------------------------
+	 * int plat_crash_console_flush()
+	 * Function to force a write of all buffered
+	 * data that hasn't been output.
+	 * Out : return -1 on error else return 0.
+	 * Clobber list : x0, x1
+	 * ---------------------------------------------
+	 */
+func plat_crash_console_flush
+	mov_imm	x0, PLAT_RPI3_UART_BASE
+	b	console_16550_core_flush
+endfunc plat_crash_console_flush
+
+	/* ---------------------------------------------
+	 * void plat_reset_handler(void);
+	 * ---------------------------------------------
+	 */
+func plat_reset_handler
+	/* ------------------------------------------------
+	 * Set L2 read/write cache latency:
+	 * - L2 Data RAM latency: 3 cycles (0b010)
+	 * - L2 Data RAM setup: 1 cycle (bit 5)
+	 * ------------------------------------------------
+	 */
+	mrs	x0, CORTEX_A72_L2CTLR_EL1
+	mov	x1, #0x22
+	orr	x0, x0, x1
+	msr	CORTEX_A72_L2CTLR_EL1, x0
+	isb
+
+	ret
+endfunc plat_reset_handler
diff --git a/plat/rpi/rpi4/include/plat.ld.S b/plat/rpi/rpi4/include/plat.ld.S
new file mode 100644
index 00000000..9262fad8
--- /dev/null
+++ b/plat/rpi/rpi4/include/plat.ld.S
@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Stub linker script to provide the armstub8.bin header before the actual
+ * code. If the GPU firmware finds a magic value at offset 240 in
+ * armstub8.bin, it will put the DTB and kernel load address in subsequent
+ * words. We can then read those values to find the proper NS entry point
+ * and find our DTB more flexibly.
+ */
+
+MEMORY {
+    PRERAM (rwx): ORIGIN = 0, LENGTH = 4096
+}
+
+SECTIONS
+{
+    .armstub8 . : {
+        *armstub8_header.o(.text*)
+        KEEP(*(.armstub8))
+    } >PRERAM
+}
diff --git a/plat/rpi/rpi4/include/plat_macros.S b/plat/rpi/rpi4/include/plat_macros.S
new file mode 100644
index 00000000..6007d031
--- /dev/null
+++ b/plat/rpi/rpi4/include/plat_macros.S
@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#ifndef PLAT_MACROS_S
+#define PLAT_MACROS_S
+
+	/* ---------------------------------------------
+	 * The below required platform porting macro
+	 * prints out relevant platform registers
+	 * whenever an unhandled exception is taken in
+	 * BL31.
+	 * Clobbers: x0 - x10, x16, x17, sp
+	 * ---------------------------------------------
+	 */
+	.macro plat_crash_print_regs
+	.endm
+
+#endif /* PLAT_MACROS_S */
diff --git a/plat/rpi/rpi4/include/platform_def.h b/plat/rpi/rpi4/include/platform_def.h
new file mode 100644
index 00000000..a9ecdba2
--- /dev/null
+++ b/plat/rpi/rpi4/include/platform_def.h
@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef PLATFORM_DEF_H
+#define PLATFORM_DEF_H
+
+#include <arch.h>
+#include <common/tbbr/tbbr_img_def.h>
+#include <lib/utils_def.h>
+#include <plat/common/common_def.h>
+
+#include "rpi_hw.h"
+
+/* Special value used to verify platform parameters from BL2 to BL31 */
+#define RPI3_BL31_PLAT_PARAM_VAL	ULL(0x0F1E2D3C4B5A6978)
+
+#define PLATFORM_STACK_SIZE		ULL(0x1000)
+
+#define PLATFORM_MAX_CPUS_PER_CLUSTER	U(4)
+#define PLATFORM_CLUSTER_COUNT		U(1)
+#define PLATFORM_CLUSTER0_CORE_COUNT	PLATFORM_MAX_CPUS_PER_CLUSTER
+#define PLATFORM_CORE_COUNT		PLATFORM_CLUSTER0_CORE_COUNT
+
+#define RPI4_PRIMARY_CPU		U(0)
+
+#define PLAT_MAX_PWR_LVL		MPIDR_AFFLVL1
+#define PLAT_NUM_PWR_DOMAINS		(PLATFORM_CLUSTER_COUNT + \
+					 PLATFORM_CORE_COUNT)
+
+#define PLAT_MAX_RET_STATE		U(1)
+#define PLAT_MAX_OFF_STATE		U(2)
+
+/* Local power state for power domains in Run state. */
+#define PLAT_LOCAL_STATE_RUN		U(0)
+/* Local power state for retention. Valid only for CPU power domains */
+#define PLAT_LOCAL_STATE_RET		U(1)
+/*
+ * Local power state for OFF/power-down. Valid for CPU and cluster power
+ * domains.
+ */
+#define PLAT_LOCAL_STATE_OFF		U(2)
+
+/*
+ * Macros used to parse state information from State-ID if it is using the
+ * recommended encoding for State-ID.
+ */
+#define PLAT_LOCAL_PSTATE_WIDTH		U(4)
+#define PLAT_LOCAL_PSTATE_MASK		((U(1) << PLAT_LOCAL_PSTATE_WIDTH) - 1)
+
+/*
+ * Some data must be aligned on the biggest cache line size in the platform.
+ * This is known only to the platform as it might have a combination of
+ * integrated and external caches.
+ */
+#define CACHE_WRITEBACK_SHIFT		U(6)
+#define CACHE_WRITEBACK_GRANULE		(U(1) << CACHE_WRITEBACK_SHIFT)
+
+/*
+ * I/O registers.
+ */
+#define DEVICE0_BASE			RPI_IO_BASE
+#define DEVICE0_SIZE			RPI_IO_SIZE
+
+/*
+ * Mailbox to control the secondary cores. All secondary cores are held in a
+ * wait loop in cold boot. To release them perform the following steps (plus
+ * any additional barriers that may be needed):
+ *
+ *     uint64_t *entrypoint = (uint64_t *)PLAT_RPI3_TM_ENTRYPOINT;
+ *     *entrypoint = ADDRESS_TO_JUMP_TO;
+ *
+ *     uint64_t *mbox_entry = (uint64_t *)PLAT_RPI3_TM_HOLD_BASE;
+ *     mbox_entry[cpu_id] = PLAT_RPI3_TM_HOLD_STATE_GO;
+ *
+ *     sev();
+ */
+/* The secure entry point to be used on warm reset by all CPUs. */
+#define PLAT_RPI3_TM_ENTRYPOINT		0x100
+#define PLAT_RPI3_TM_ENTRYPOINT_SIZE	ULL(8)
+
+/* Hold entries for each CPU. */
+#define PLAT_RPI3_TM_HOLD_BASE		(PLAT_RPI3_TM_ENTRYPOINT + \
+					 PLAT_RPI3_TM_ENTRYPOINT_SIZE)
+#define PLAT_RPI3_TM_HOLD_ENTRY_SIZE	ULL(8)
+#define PLAT_RPI3_TM_HOLD_SIZE		(PLAT_RPI3_TM_HOLD_ENTRY_SIZE * \
+					 PLATFORM_CORE_COUNT)
+
+#define PLAT_RPI3_TRUSTED_MAILBOX_SIZE	(PLAT_RPI3_TM_ENTRYPOINT_SIZE + \
+					 PLAT_RPI3_TM_HOLD_SIZE)
+
+#define PLAT_RPI3_TM_HOLD_STATE_WAIT	ULL(0)
+#define PLAT_RPI3_TM_HOLD_STATE_GO	ULL(1)
+
+/*
+ * BL31 specific defines.
+ *
+ * Put BL31 at the top of the Trusted SRAM. BL31_BASE is calculated using the
+ * current BL31 debug size plus a little space for growth.
+ */
+#define PLAT_MAX_BL31_SIZE		ULL(0x80000)
+
+#define BL31_BASE			ULL(0x1000)
+#define BL31_LIMIT			ULL(0x80000)
+#define BL31_PROGBITS_LIMIT		ULL(0x80000)
+
+#define SEC_SRAM_ID			0
+#define SEC_DRAM_ID			1
+
+/*
+ * Other memory-related defines.
+ */
+#define PLAT_PHY_ADDR_SPACE_SIZE	(ULL(1) << 32)
+#define PLAT_VIRT_ADDR_SPACE_SIZE	(ULL(1) << 32)
+
+#define MAX_MMAP_REGIONS		8
+#define MAX_XLAT_TABLES			4
+
+#define MAX_IO_DEVICES			U(3)
+#define MAX_IO_HANDLES			U(4)
+
+#define MAX_IO_BLOCK_DEVICES		U(1)
+
+/*
+ * Serial-related constants.
+ */
+#define PLAT_RPI3_UART_BASE		RPI3_MINI_UART_BASE
+#define PLAT_RPI3_UART_BAUDRATE		ULL(115200)
+
+/*
+ * System counter
+ */
+#define SYS_COUNTER_FREQ_IN_TICKS	ULL(54000000)
+
+#endif /* PLATFORM_DEF_H */
diff --git a/plat/rpi/rpi4/include/rpi_hw.h b/plat/rpi/rpi4/include/rpi_hw.h
new file mode 100644
index 00000000..ed367ee2
--- /dev/null
+++ b/plat/rpi/rpi4/include/rpi_hw.h
@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef RPI_HW_H
+#define RPI_HW_H
+
+#include <lib/utils_def.h>
+
+/*
+ * Peripherals
+ */
+
+#define RPI_IO_BASE			ULL(0xFE000000)
+#define RPI_IO_SIZE			ULL(0x02000000)
+
+/*
+ * ARM <-> VideoCore mailboxes
+ */
+#define RPI3_MBOX_OFFSET		ULL(0x0000B880)
+#define RPI3_MBOX_BASE			(RPI_IO_BASE + RPI3_MBOX_OFFSET)
+/* VideoCore -> ARM */
+#define RPI3_MBOX0_READ_OFFSET		ULL(0x00000000)
+#define RPI3_MBOX0_PEEK_OFFSET		ULL(0x00000010)
+#define RPI3_MBOX0_SENDER_OFFSET	ULL(0x00000014)
+#define RPI3_MBOX0_STATUS_OFFSET	ULL(0x00000018)
+#define RPI3_MBOX0_CONFIG_OFFSET	ULL(0x0000001C)
+/* ARM -> VideoCore */
+#define RPI3_MBOX1_WRITE_OFFSET		ULL(0x00000020)
+#define RPI3_MBOX1_PEEK_OFFSET		ULL(0x00000030)
+#define RPI3_MBOX1_SENDER_OFFSET	ULL(0x00000034)
+#define RPI3_MBOX1_STATUS_OFFSET	ULL(0x00000038)
+#define RPI3_MBOX1_CONFIG_OFFSET	ULL(0x0000003C)
+/* Mailbox status constants */
+#define RPI3_MBOX_STATUS_FULL_MASK	U(0x80000000) /* Set if full */
+#define RPI3_MBOX_STATUS_EMPTY_MASK	U(0x40000000) /* Set if empty */
+
+/*
+ * Power management, reset controller, watchdog.
+ */
+#define RPI3_IO_PM_OFFSET		ULL(0x00100000)
+#define RPI3_PM_BASE			(RPI_IO_BASE + RPI3_IO_PM_OFFSET)
+/* Registers on top of RPI3_PM_BASE. */
+#define RPI3_PM_RSTC_OFFSET		ULL(0x0000001C)
+#define RPI3_PM_RSTS_OFFSET		ULL(0x00000020)
+#define RPI3_PM_WDOG_OFFSET		ULL(0x00000024)
+/* Watchdog constants */
+#define RPI3_PM_PASSWORD		U(0x5A000000)
+#define RPI3_PM_RSTC_WRCFG_MASK		U(0x00000030)
+#define RPI3_PM_RSTC_WRCFG_FULL_RESET	U(0x00000020)
+/*
+ * The RSTS register is used by the VideoCore firmware when booting the
+ * Raspberry Pi to know which partition to boot from. The partition value is
+ * formed by bits 0, 2, 4, 6, 8 and 10. Partition 63 is used by said firmware
+ * to indicate halt.
+ */
+#define RPI3_PM_RSTS_WRCFG_HALT		U(0x00000555)
+
+/*
+ * Clock controller
+ */
+#define RPI4_IO_CLOCK_OFFSET		ULL(0x00101000)
+#define RPI4_CLOCK_BASE			(RPI_IO_BASE + RPI4_IO_CLOCK_OFFSET)
+#define RPI4_VPU_CLOCK_DIVIDER		ULL(0x0000000c)
+
+/*
+ * Hardware random number generator.
+ */
+#define RPI3_IO_RNG_OFFSET		ULL(0x00104000)
+#define RPI3_RNG_BASE			(RPI_IO_BASE + RPI3_IO_RNG_OFFSET)
+#define RPI3_RNG_CTRL_OFFSET		ULL(0x00000000)
+#define RPI3_RNG_STATUS_OFFSET		ULL(0x00000004)
+#define RPI3_RNG_DATA_OFFSET		ULL(0x00000008)
+#define RPI3_RNG_INT_MASK_OFFSET	ULL(0x00000010)
+/* Enable/disable RNG */
+#define RPI3_RNG_CTRL_ENABLE		U(0x1)
+#define RPI3_RNG_CTRL_DISABLE		U(0x0)
+/* Number of currently available words */
+#define RPI3_RNG_STATUS_NUM_WORDS_SHIFT	U(24)
+#define RPI3_RNG_STATUS_NUM_WORDS_MASK	U(0xFF)
+/* Value to mask interrupts caused by the RNG */
+#define RPI3_RNG_INT_MASK_DISABLE	U(0x1)
+
+/*
+ * Serial port (called 'Mini UART' in the Broadcom documentation).
+ */
+#define RPI3_IO_MINI_UART_OFFSET	ULL(0x00215040)
+#define RPI3_MINI_UART_BASE		(RPI_IO_BASE + RPI3_IO_MINI_UART_OFFSET)
+#define PLAT_RPI4_VPU_CLK_RATE		ULL(1000000000)
+
+/*
+ * GPIO controller
+ */
+#define RPI3_IO_GPIO_OFFSET		ULL(0x00200000)
+#define RPI3_GPIO_BASE			(RPI_IO_BASE + RPI3_IO_GPIO_OFFSET)
+
+/*
+ * SDHost controller
+ */
+#define RPI3_IO_SDHOST_OFFSET           ULL(0x00202000)
+#define RPI3_SDHOST_BASE                (RPI_IO_BASE + RPI3_IO_SDHOST_OFFSET)
+
+/*
+ * GIC interrupt controller
+ */
+#define RPI_HAVE_GIC
+#define RPI4_GIC_GICD_BASE		ULL(0xff841000)
+#define RPI4_GIC_GICC_BASE		ULL(0xff842000)
+
+#define	RPI4_LOCAL_CONTROL_BASE_ADDRESS		ULL(0xff800000)
+#define	RPI4_LOCAL_CONTROL_PRESCALER		ULL(0xff800008)
+
+#endif /* RPI_HW_H */
diff --git a/plat/rpi/rpi4/platform.mk b/plat/rpi/rpi4/platform.mk
new file mode 100644
index 00000000..2038021a
--- /dev/null
+++ b/plat/rpi/rpi4/platform.mk
@@ -0,0 +1,103 @@
+#
+# Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+include lib/libfdt/libfdt.mk
+include lib/xlat_tables_v2/xlat_tables.mk
+
+PLAT_INCLUDES		:=	-Iplat/rpi/common/include		\
+				-Iplat/rpi/rpi4/include
+
+PLAT_BL_COMMON_SOURCES	:=	drivers/ti/uart/aarch64/16550_console.S	\
+				plat/rpi/common/rpi3_common.c		\
+				${XLAT_TABLES_LIB_SRCS}
+
+BL31_SOURCES		+=	lib/cpus/aarch64/cortex_a72.S		\
+				plat/rpi/rpi4/aarch64/plat_helpers.S	\
+				plat/rpi/rpi4/aarch64/armstub8_header.S	\
+				drivers/arm/gic/common/gic_common.c     \
+				drivers/arm/gic/v2/gicv2_helpers.c      \
+				drivers/arm/gic/v2/gicv2_main.c         \
+				plat/common/plat_gicv2.c                \
+				plat/rpi/rpi4/rpi4_bl31_setup.c		\
+				plat/rpi/common/rpi3_pm.c		\
+				plat/common/plat_psci_common.c		\
+				plat/rpi/common/rpi3_topology.c		\
+				common/fdt_fixup.c			\
+				${LIBFDT_SRCS}
+
+# For now we only support BL31, using the kernel loaded by the GPU firmware.
+RESET_TO_BL31		:=	1
+
+# All CPUs enter armstub8.bin.
+COLD_BOOT_SINGLE_CPU	:=	0
+
+# Tune compiler for Cortex-A72
+ifeq ($(notdir $(CC)),armclang)
+    TF_CFLAGS_aarch64	+=	-mcpu=cortex-a72
+else ifneq ($(findstring clang,$(notdir $(CC))),)
+    TF_CFLAGS_aarch64	+=	-mcpu=cortex-a72
+else
+    TF_CFLAGS_aarch64	+=	-mtune=cortex-a72
+endif
+
+# Add support for platform supplied linker script for BL31 build
+$(eval $(call add_define,PLAT_EXTRA_LD_SCRIPT))
+
+# Enable all errata workarounds for Cortex-A72
+ERRATA_A72_859971		:= 1
+
+WORKAROUND_CVE_2017_5715	:= 1
+
+# Add new default target when compiling this platform
+all: bl31
+
+# Build config flags
+# ------------------
+
+# Disable stack protector by default
+ENABLE_STACK_PROTECTOR	 	:= 0
+
+# Have different sections for code and rodata
+SEPARATE_CODE_AND_RODATA	:= 1
+
+# Use Coherent memory
+USE_COHERENT_MEM		:= 1
+
+# Platform build flags
+# --------------------
+
+# There is not much else than a Linux kernel to load at the moment.
+RPI3_DIRECT_LINUX_BOOT		:= 1
+
+# BL33 images are in AArch64 by default
+RPI3_BL33_IN_AARCH32		:= 0
+
+# UART to use at runtime. -1 means the runtime UART is disabled.
+# Any other value means the default UART will be used.
+RPI3_RUNTIME_UART		:= 0
+
+# Use normal memory mapping for ROM, FIP, SRAM and DRAM
+RPI3_USE_UEFI_MAP		:= 0
+
+# Process platform flags
+# ----------------------
+
+$(eval $(call add_define,RPI3_BL33_IN_AARCH32))
+$(eval $(call add_define,RPI3_DIRECT_LINUX_BOOT))
+ifdef RPI3_PRELOADED_DTB_BASE
+$(eval $(call add_define,RPI3_PRELOADED_DTB_BASE))
+endif
+$(eval $(call add_define,RPI3_RUNTIME_UART))
+$(eval $(call add_define,RPI3_USE_UEFI_MAP))
+
+ifeq (${ARCH},aarch32)
+  $(error Error: AArch32 not supported on rpi4)
+endif
+
+ifneq ($(ENABLE_STACK_PROTECTOR), 0)
+PLAT_BL_COMMON_SOURCES	+=	drivers/rpi3/rng/rpi3_rng.c		\
+				plat/rpi/common/rpi3_stack_protector.c
+endif
diff --git a/plat/rpi/rpi4/rpi4_bl31_setup.c b/plat/rpi/rpi4/rpi4_bl31_setup.c
new file mode 100644
index 00000000..53ab0c2e
--- /dev/null
+++ b/plat/rpi/rpi4/rpi4_bl31_setup.c
@@ -0,0 +1,278 @@
+/*
+ * Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <libfdt.h>
+
+#include <platform_def.h>
+#include <arch_helpers.h>
+#include <common/bl_common.h>
+#include <lib/mmio.h>
+#include <lib/xlat_tables/xlat_mmu_helpers.h>
+#include <lib/xlat_tables/xlat_tables_defs.h>
+#include <lib/xlat_tables/xlat_tables_v2.h>
+#include <plat/common/platform.h>
+#include <common/fdt_fixup.h>
+#include <libfdt.h>
+
+#include <drivers/arm/gicv2.h>
+
+#include <rpi_shared.h>
+
+/*
+ * Fields at the beginning of armstub8.bin.
+ * While building the BL31 image, we put the stub magic into the binary.
+ * The GPU firmware detects this at boot time, clears that field as a
+ * confirmation and puts the kernel and DT address in the following words.
+ */
+extern uint32_t stub_magic;
+extern uint32_t dtb_ptr32;
+extern uint32_t kernel_entry32;
+
+static const gicv2_driver_data_t rpi4_gic_data = {
+	.gicd_base = RPI4_GIC_GICD_BASE,
+	.gicc_base = RPI4_GIC_GICC_BASE,
+};
+
+/*
+ * To be filled by the code below. At the moment BL32 is not supported.
+ * In the future these might be passed down from BL2.
+ */
+static entry_point_info_t bl32_image_ep_info;
+static entry_point_info_t bl33_image_ep_info;
+
+/*******************************************************************************
+ * Return a pointer to the 'entry_point_info' structure of the next image for
+ * the security state specified. BL33 corresponds to the non-secure image type
+ * while BL32 corresponds to the secure image type. A NULL pointer is returned
+ * if the image does not exist.
+ ******************************************************************************/
+entry_point_info_t *bl31_plat_get_next_image_ep_info(uint32_t type)
+{
+	entry_point_info_t *next_image_info;
+
+	assert(sec_state_is_valid(type) != 0);
+
+	next_image_info = (type == NON_SECURE)
+			? &bl33_image_ep_info : &bl32_image_ep_info;
+
+	/* None of the images can have 0x0 as the entrypoint. */
+	if (next_image_info->pc) {
+		return next_image_info;
+	} else {
+		return NULL;
+	}
+}
+
+uintptr_t plat_get_ns_image_entrypoint(void)
+{
+#ifdef PRELOADED_BL33_BASE
+	return PRELOADED_BL33_BASE;
+#else
+	/* Cleared by the GPU if kernel address is valid. */
+	if (stub_magic == 0)
+		return kernel_entry32;
+
+	WARN("Stub magic failure, using default kernel address 0x80000\n");
+	return 0x80000;
+#endif
+}
+
+static uintptr_t rpi4_get_dtb_address(void)
+{
+#ifdef RPI3_PRELOADED_DTB_BASE
+	return RPI3_PRELOADED_DTB_BASE;
+#else
+	/* Cleared by the GPU if DTB address is valid. */
+	if (stub_magic == 0)
+		return dtb_ptr32;
+
+	WARN("Stub magic failure, DTB address unknown\n");
+	return 0;
+#endif
+}
+
+static void ldelay(register_t delay)
+{
+	__asm__ volatile (
+		"1:\tcbz %0, 2f\n\t"
+		"sub %0, %0, #1\n\t"
+		"b 1b\n"
+		"2:"
+		: "=&r" (delay) : "0" (delay)
+	);
+}
+
+/*******************************************************************************
+ * Perform any BL31 early platform setup. Here is an opportunity to copy
+ * parameters passed by the calling EL (S-EL1 in BL2 & EL3 in BL1) before
+ * they are lost (potentially). This needs to be done before the MMU is
+ * initialized so that the memory layout can be used while creating page
+ * tables. BL2 has flushed this information to memory, so we are guaranteed
+ * to pick up good data.
+ ******************************************************************************/
+void bl31_early_platform_setup2(u_register_t arg0, u_register_t arg1,
+				u_register_t arg2, u_register_t arg3)
+
+{
+	uint32_t div_reg;
+
+	/*
+	 * LOCAL_CONTROL:
+	 * Bit 9 clear: Increment by 1 (vs. 2).
+	 * Bit 8 clear: Timer source is 19.2MHz crystal (vs. APB).
+	 */
+	mmio_write_32(RPI4_LOCAL_CONTROL_BASE_ADDRESS, 0);
+
+	/* LOCAL_PRESCALER; divide-by (0x80000000 / register_val) == 1 */
+	mmio_write_32(RPI4_LOCAL_CONTROL_PRESCALER, 0x80000000);
+
+	/* Early GPU firmware revisions need a little break here. */
+	ldelay(100000);
+
+	/*
+	 * Initialize the console to provide early debug support.
+	 * Different GPU firmware revisions set up the VPU divider differently,
+	 * so read the actual divider register to learn the UART base clock
+	 * rate. The divider is encoded as a 12.12 fixed point number, but we
+	 * just care about the integer part of it.
+	 */
+	div_reg = mmio_read_32(RPI4_CLOCK_BASE + RPI4_VPU_CLOCK_DIVIDER);
+	div_reg = (div_reg >> 12) & 0xfff;
+	if (div_reg == 0)
+		div_reg = 1;
+	rpi3_console_init(PLAT_RPI4_VPU_CLK_RATE / div_reg);
+
+	bl33_image_ep_info.pc = plat_get_ns_image_entrypoint();
+	bl33_image_ep_info.spsr = rpi3_get_spsr_for_bl33_entry();
+	SET_SECURITY_STATE(bl33_image_ep_info.h.attr, NON_SECURE);
+
+#if RPI3_DIRECT_LINUX_BOOT
+# if RPI3_BL33_IN_AARCH32
+	/*
+	 * According to the file ``Documentation/arm/Booting`` of the Linux
+	 * kernel tree, Linux expects:
+	 * r0 = 0
+	 * r1 = machine type number, optional in DT-only platforms (~0 if so)
+	 * r2 = Physical address of the device tree blob
+	 */
+	VERBOSE("rpi4: Preparing to boot 32-bit Linux kernel\n");
+	bl33_image_ep_info.args.arg0 = 0U;
+	bl33_image_ep_info.args.arg1 = ~0U;
+	bl33_image_ep_info.args.arg2 = rpi4_get_dtb_address();
+# else
+	/*
+	 * According to the file ``Documentation/arm64/booting.txt`` of the
+	 * Linux kernel tree, Linux expects the physical address of the device
+	 * tree blob (DTB) in x0, while x1-x3 are reserved for future use and
+	 * must be 0.
+	 */
+	VERBOSE("rpi4: Preparing to boot 64-bit Linux kernel\n");
+	bl33_image_ep_info.args.arg0 = rpi4_get_dtb_address();
+	bl33_image_ep_info.args.arg1 = 0ULL;
+	bl33_image_ep_info.args.arg2 = 0ULL;
+	bl33_image_ep_info.args.arg3 = 0ULL;
+# endif /* RPI3_BL33_IN_AARCH32 */
+#endif /* RPI3_DIRECT_LINUX_BOOT */
+}
+
+void bl31_plat_arch_setup(void)
+{
+	/*
+	 * Is the dtb_ptr32 pointer valid? If yes, map the DTB region.
+	 * We map the 2MB region the DTB start address lives in, plus
+	 * the next 2MB, to have enough room for expansion.
+	 */
+	if (stub_magic == 0) {
+		unsigned long long dtb_region = dtb_ptr32;
+
+		dtb_region &= ~0x1fffff;	/* Align to 2 MB. */
+		mmap_add_region(dtb_region, dtb_region, 4U << 20,
+				MT_MEMORY | MT_RW | MT_NS);
+	}
+	/*
+	 * Add the first page of memory, which holds the stub magic,
+	 * the kernel and the DT address.
+	 * This also holds the secondary CPU's entrypoints and mailboxes.
+	 */
+	mmap_add_region(0, 0, 4096, MT_NON_CACHEABLE | MT_RW | MT_SECURE);
+
+	rpi3_setup_page_tables(BL31_BASE, BL31_END - BL31_BASE,
+			       BL_CODE_BASE, BL_CODE_END,
+			       BL_RO_DATA_BASE, BL_RO_DATA_END
+#if USE_COHERENT_MEM
+			       , BL_COHERENT_RAM_BASE, BL_COHERENT_RAM_END
+#endif
+			      );
+
+	enable_mmu_el3(0);
+}
+
+static uint32_t dtb_size(const void *dtb)
+{
+	const uint32_t *dtb_header = dtb;
+
+	return fdt32_to_cpu(dtb_header[1]);
+}
+
+static void rpi4_prepare_dtb(void)
+{
+	void *dtb = (void *)rpi4_get_dtb_address();
+	uint32_t gic_int_prop[3];
+	int ret, offs;
+
+	/* Return if no device tree is detected */
+	if (fdt_check_header(dtb) != 0)
+		return;
+
+	ret = fdt_open_into(dtb, dtb, 0x100000);
+	if (ret < 0) {
+		ERROR("Invalid Device Tree at %p: error %d\n", dtb, ret);
+		return;
+	}
+
+	if (dt_add_psci_node(dtb)) {
+		ERROR("Failed to add PSCI Device Tree node\n");
+		return;
+	}
+
+	if (dt_add_psci_cpu_enable_methods(dtb)) {
+		ERROR("Failed to add PSCI cpu enable methods in Device Tree\n");
+		return;
+	}
+
+	/* Reserve memory used by Trusted Firmware. */
+	if (fdt_add_reserved_memory(dtb, "atf@0", 0, 0x80000))
+		WARN("Failed to add reserved memory nodes to DT.\n");
+
+	offs = fdt_node_offset_by_compatible(dtb, 0, "arm,gic-400");
+	gic_int_prop[0] = cpu_to_fdt32(1);		// PPI
+	gic_int_prop[1] = cpu_to_fdt32(9);		// PPI #9
+	gic_int_prop[2] = cpu_to_fdt32(0x0f04);		// all cores, level high
+	fdt_setprop(dtb, offs, "interrupts", gic_int_prop, 12);
+
+	offs = fdt_path_offset(dtb, "/chosen");
+	fdt_setprop_string(dtb, offs, "stdout-path", "serial0");
+
+	ret = fdt_pack(dtb);
+	if (ret < 0)
+		ERROR("Failed to pack Device Tree at %p: error %d\n", dtb, ret);
+
+	clean_dcache_range((uintptr_t)dtb, dtb_size(dtb));
+	INFO("Changed device tree to advertise PSCI.\n");
+}
+
+void bl31_platform_setup(void)
+{
+	rpi4_prepare_dtb();
+
+	/* Configure the interrupt controller */
+	gicv2_driver_init(&rpi4_gic_data);
+	gicv2_distif_init();
+	gicv2_pcpu_distif_init();
+	gicv2_cpuif_enable();
+}