mirror of https://github.com/wolfSSL/wolfBoot.git
116 lines
3.6 KiB
C
116 lines
3.6 KiB
C
/* app_tegra234.c
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*
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* Test bare-metal boot application
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*
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* Copyright (C) 2026 wolfSSL Inc.
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*
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* This file is part of wolfBoot.
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*
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* wolfBoot is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* wolfBoot is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
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*/
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#include <stdint.h>
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#include "wolfboot/wolfboot.h"
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#ifdef TARGET_tegra234
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#include "hal/tegra234.h"
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/* Same TCU console the bootloader chain and wolfBoot use (see hal/tegra234.h).
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* The MMU is off here, so the mailbox register is driven directly. One byte
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* per message keeps this payload trivial. */
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#define TCU_TX_MBOX ((volatile uint32_t*)(uintptr_t)TEGRA_TCU_TX_MBOX)
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/* Bounded spin: no timer is set up in this payload, so a plain counter is
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* enough to keep a stalled SPE from hanging the PoC mid-message. */
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#define TCU_TX_SPIN_MAX 1000000
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static void tcu_putc(char c)
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{
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unsigned int spin = 0;
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while ((*TCU_TX_MBOX & TEGRA_TCU_MBOX_FULL) != 0) {
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if (++spin > TCU_TX_SPIN_MAX)
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return; /* drop the character rather than stall forever */
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}
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*TCU_TX_MBOX = TEGRA_TCU_MBOX_FULL |
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(1u << TEGRA_TCU_MBOX_NBYTES_SHIFT) | (uint8_t)c;
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}
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static void tcu_puts(const char* s)
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{
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while (*s != '\0') {
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if (*s == '\n')
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tcu_putc('\r');
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tcu_putc(*s++);
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}
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}
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static void tcu_puthex(uint64_t v)
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{
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int i;
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tcu_puts("0x");
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for (i = 60; i >= 0; i -= 4)
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tcu_putc("0123456789abcdef"[(v >> i) & 0xF]);
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}
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/* FDT magic 0xd00dfeed, stored big-endian -> reads as 0xedfe0dd0 here */
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#define FDT_MAGIC_LE 0xedfe0dd0u
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/* The DTB pointer arrives as the first argument: wolfBoot's el2_to_el1_boot()
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* leaves it in x0 per the arm64 boot protocol, and boot_arm64_start.S forwards
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* it to main per AAPCS. Taking it as a parameter rather than reading x0 with
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* inline asm keeps this correct at any optimization level. */
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void __attribute__((section(".boot"))) main(uint64_t dtb) {
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uint64_t el;
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__asm__ volatile("mrs %0, CurrentEL" : "=r"(el));
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el >>= 2;
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tcu_puts("\n*** wolfBoot Tegra234 PoC payload: verified + booted ***\n");
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/* Prove the EL2->EL1 drop happened, and that a valid FDT arrived in x0:
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* the full arm64 boot contract for a signed payload. */
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tcu_puts(" CurrentEL = EL");
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tcu_putc('0' + (char)(el & 3));
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tcu_puts("\n");
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tcu_puts(" DTB (x0) = ");
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tcu_puthex(dtb);
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tcu_puts("\n DTB magic = ");
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/* Range- and alignment-check before dereferencing: with the MMU off this
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* is Device memory, where an unaligned access faults. A stray pointer
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* should be reported, not taken. */
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if (dtb < TEGRA234_DRAM_BASE || dtb > (TEGRA234_DRAM_END - 4) ||
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(dtb & 0x3) != 0) {
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tcu_puts("(pointer not in DRAM or misaligned)\n");
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}
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else if (*((volatile uint32_t*)(uintptr_t)dtb) == FDT_MAGIC_LE) {
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tcu_puts("OK (0xd00dfeed)\n");
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}
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else {
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tcu_puthex(*((volatile uint32_t*)(uintptr_t)dtb));
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tcu_puts(" (BAD)\n");
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}
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tcu_puts("*** PoC complete: parked ***\n");
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/* Wait for reboot */
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while(1)
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;
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}
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#endif /** TARGET_tegra234 **/
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