From dc52610bd8df8e92120bf5bbf92d5d3237c8394d Mon Sep 17 00:00:00 2001
From: Michael Scire <SciresM@gmail.com>
Date: Sun, 29 Nov 2020 18:17:51 -0800
Subject: [PATCH] fusee-primary: fix reboot-to-self for decompressed code

---
 .../fusee-primary-main/linker.ld              |  6 ++
 .../fusee-primary-main/src/reboot_start.s     | 76 +++++++++++++++++++
 .../fusee-primary-main/src/utils.c            | 27 ++++++-
 3 files changed, 108 insertions(+), 1 deletion(-)
 create mode 100644 fusee/fusee-primary/fusee-primary-main/src/reboot_start.s

diff --git a/fusee/fusee-primary/fusee-primary-main/linker.ld b/fusee/fusee-primary/fusee-primary-main/linker.ld
index 0e46aa6b4..cc397c02d 100644
--- a/fusee/fusee-primary/fusee-primary-main/linker.ld
+++ b/fusee/fusee-primary/fusee-primary-main/linker.ld
@@ -32,6 +32,11 @@ SECTIONS
         KEEP( *(.text.start) )
         KEEP( *(.init) )
         . = ALIGN(32);
+        PROVIDE (__reboot_start__ = ABSOLUTE(.));
+        KEEP( *(.reboot*) )
+        . = ALIGN(4);
+        PROVIDE (__reboot_end__   = ABSOLUTE(.));
+        . = ALIGN(32);
     } >main :crt0
 
     .chainloader_loadable :
@@ -59,6 +64,7 @@ SECTIONS
     {
         . = ALIGN(32);
         /* .text */
+        *(.text.reboot_to_self)
         *(.text)
         *(.text.*)
         *(.glue_7)
diff --git a/fusee/fusee-primary/fusee-primary-main/src/reboot_start.s b/fusee/fusee-primary/fusee-primary-main/src/reboot_start.s
new file mode 100644
index 000000000..e2bbe8bb1
--- /dev/null
+++ b/fusee/fusee-primary/fusee-primary-main/src/reboot_start.s
@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+.macro CLEAR_GPR_REG_ITER
+    mov r\@, #0
+.endm
+
+.section .reboot.start, "ax", %progbits
+.arm
+.align 5
+.global reboot_start
+.type   reboot_start, %function
+reboot_start:
+    /* Switch to system mode, mask all interrupts, clear all flags */
+    msr cpsr_cxsf, #0xDF
+
+    /* Relocate reboot start to 0x4003E000. */
+    ldr r0, =0x4003E000
+    adr r1, reboot_start
+    cmp r0, r1
+    beq 1f
+
+    mov r2, #0x1000
+0:
+    ldmia r1!, {r5-r12}
+    stmia r0!, {r5-r12}
+    subs  r2, #0x20
+    bne 0b
+
+    ldr r0, =0x4003E000
+    adr r1, reboot_start
+    adr r2, 1f
+    sub r2, r2, r1
+    add r2, r2, r0
+    bx  r2
+
+1:
+
+    /* Restore our low iram code. */
+    ldr r0, =0x40008000
+    ldr r1, =0x40030000
+    mov r2, #0x8000
+0:
+    ldmia r1!, {r5-r12}
+    stmia r0!, {r5-r12}
+    subs  r2, #0x20
+    bne 0b
+
+    /* Restore our upper stub code. */
+    ldr r0, =0x40010000
+    ldr r1, =0x4003D000
+    mov r2, #0x1000
+0:
+    ldmia r1!, {r5-r12}
+    stmia r0!, {r5-r12}
+    subs  r2, #0x20
+    bne 0b
+
+    /* Jump to start. */
+    ldr r0, =0x40008000
+    bx  r0
+
+0:  b 0b
\ No newline at end of file
diff --git a/fusee/fusee-primary/fusee-primary-main/src/utils.c b/fusee/fusee-primary/fusee-primary-main/src/utils.c
index 8b407446b..96eb0591b 100644
--- a/fusee/fusee-primary/fusee-primary-main/src/utils.c
+++ b/fusee/fusee-primary/fusee-primary-main/src/utils.c
@@ -37,6 +37,8 @@
 #undef u8
 #undef u32
 
+extern uint8_t __reboot_start__[], __reboot_end__[];
+
 void wait(uint32_t microseconds) {
     uint32_t old_time = TIMERUS_CNTR_1US_0;
     while (TIMERUS_CNTR_1US_0 - old_time <= microseconds) {
@@ -80,8 +82,31 @@ __attribute__((noreturn)) void reboot_to_self(void) {
         write32le((void *)0x4003F000, i, read32le(rebootstub_bin, i));
     }
 
+    /* Copy our low part into safe IRAM. */
+    for (size_t i = 0; i < 0x8000; i += sizeof(uint32_t)) {
+        write32le((void *)0x40030000, i, read32le((void *)0x40008000, i));
+    }
+
+    /* Copy our start page into fatal IRAM. */
+    for (size_t i = 0; i < 0x1000; i += sizeof(uint32_t)) {
+        write32le((void *)0x4003D000, i, read32le((void *)0x40010000, i));
+    }
+
+    /* Copy our reboot handler to the rebootstub target. */
+    for (size_t i = 0; i < (__reboot_end__ - __reboot_start__); i += sizeof(uint32_t)) {
+        write32le((void *)0x40010000, i, read32le(__reboot_start__, i));
+    }
+
     /* Trigger warm reboot. */
-    pmc_reboot(1 << 0);
+    APBDEV_PMC_SCRATCH0_0 = (1 << 0);
+
+    /* Reset the processor. */
+    APBDEV_PMC_CONTROL = BIT(4);
+
+    while (true) {
+        /* Wait for reboot. */
+    }
+
 }
 
 __attribute__((noreturn)) void wait_for_button_and_reboot(void) {