refactor(rpi): move more platform-specific code into common

In preparation for RPi 5 support, which will reuse most of the RPi 4
logic except for DTB patching.

Change-Id: I6f6ef96933711a1798757a3389adae1b8ee3de6c
Signed-off-by: Mario Bălănică <mariobalanica02@gmail.com>
diff --git a/plat/rpi/common/rpi4_bl31_setup.c b/plat/rpi/common/rpi4_bl31_setup.c
new file mode 100644
index 0000000..a7228fd
--- /dev/null
+++ b/plat/rpi/common/rpi4_bl31_setup.c
@@ -0,0 +1,209 @@
+/*
+ * Copyright (c) 2015-2024, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <inttypes.h>
+#include <stdint.h>
+
+#include <arch_helpers.h>
+#include <common/bl_common.h>
+#include <drivers/arm/gicv2.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 <platform_def.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
+}
+
+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)
+
+{
+	/*
+	 * 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. */
+	rpi3_console_init();
+
+	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("rpi: 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("rpi: 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);
+}
+
+void bl31_platform_setup(void)
+{
+	/* Configure the interrupt controller */
+	gicv2_driver_init(&rpi4_gic_data);
+	gicv2_distif_init();
+	gicv2_pcpu_distif_init();
+	gicv2_cpuif_enable();
+
+	plat_rpi_bl31_custom_setup();
+}