Add basic support for Raspberry Pi 4

The Raspberry Pi 4 is a single board computer with four Cortex-A72
cores. From a TF-A perspective it is quite similar to the Raspberry Pi
3, although it comes with more memory (up to 4GB) and has a GIC.

This initial port though differs quite a lot from the existing rpi3
platform port, mainly due to taking a much simpler and more robust
approach to loading the non-secure payload:
The GPU firmware of the SoC, which is responsible for initial platform
setup (including DRAM initialisation), already loads the kernel, device
tree and the "armstub" into DRAM. We take advantage of this, by placing
just a BL31 component into the armstub8.bin component, which will be
executed first, in AArch64 EL3.
The non-secure payload can be a kernel or a boot loader (U-Boot or
EDK-2), disguised as the "kernel" image and loaded by the GPU firmware.

So this is just a BL31-only port, which directly drops into EL2
and executes whatever has been loaded as the "kernel" image, handing
over the DTB address in x0.

Change-Id: I636f4d1f661821566ad9e341d69ba36f6bbfb546
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

1 files changed, 187 insertions, 0 deletions

diff --git a/plat/rpi/rpi4/aarch64/plat_helpers.S b/plat/rpi/rpi4/aarch64/plat_helpers.S
new file mode 100644
index 000000000..46073b791
--- /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