From b414b986ebd5decb8396980ce1f9730b812332da Mon Sep 17 00:00:00 2001
From: keyb <git@keyb.moe>
Date: Sun, 20 Apr 2025 02:12:13 +0200
Subject: [PATCH] imp: pass around root dtb node instead of global value

---
 src/kernel/hal/rv32/boot.c |  4 ++--
 src/libs/dtb/mod.c         | 15 ++++++++-------
 src/libs/dtb/mod.h         |  4 ++--
 3 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/src/kernel/hal/rv32/boot.c b/src/kernel/hal/rv32/boot.c
index d7ad551..e85c61a 100644
--- a/src/kernel/hal/rv32/boot.c
+++ b/src/kernel/hal/rv32/boot.c
@@ -16,8 +16,8 @@ void rv32_start(__attribute__((unused)) size_t hartid, uintptr_t dtb) {
     write_csr$(stvec, (uint32_t)interrupt_kernel);
 
     BumpAllocator alloc = bump_allocator_create((void*)early_heap, sizeof(early_heap));
-    dtb_init(dtb, &alloc.base);
-    DTBNode* mem = dtb_lookup("reserved-memory");
+    DTBNode* root       = dtb_init(dtb, &alloc.base);
+    DTBNode* mem        = dtb_lookup(root, "reserved-memory");
 
     if (mem == NULL) {
         error$("Failed to find reserved-memory node in device tree");
diff --git a/src/libs/dtb/mod.c b/src/libs/dtb/mod.c
index a484794..7f59212 100644
--- a/src/libs/dtb/mod.c
+++ b/src/libs/dtb/mod.c
@@ -6,24 +6,23 @@
 
 #include "mod.h"
 
-static DTBNode* root = NULL;
-
 static uint32_t read_offset(uint8_t** offset) {
     uint32_t value = from_be32(*(uint32_t*)*offset);
     *offset += sizeof(uint32_t);
     return value;
 }
 
-static void dtb_parse(FDTHeader* dtb_header, Allocator* alloc) {
+static DTBNode* dtb_parse(FDTHeader* dtb_header, Allocator* alloc) {
     if (dtb_header == NULL) {
         error$("Device tree blob not initialized");
         abort();
     }
 
+    DTBNode* current_node = NULL;
+    DTBNode* root         = NULL;
     char const* strtab    = (char const*)((uint8_t*)dtb_header + from_be32(dtb_header->off_dt_strings));
     uint8_t* offset       = (uint8_t*)dtb_header + from_be32(dtb_header->off_dt_struct);
     int found_end         = 0;
-    DTBNode* current_node = NULL;
 
     while (!found_end) {
         uint32_t token = read_offset(&offset);
@@ -126,9 +125,11 @@ static void dtb_parse(FDTHeader* dtb_header, Allocator* alloc) {
         }
         }
     }
+
+    return root;
 }
 
-void dtb_init(uintptr_t dtb, Allocator* alloc) {
+DTBNode* dtb_init(uintptr_t dtb, Allocator* alloc) {
     FDTHeader* dtb_header = (FDTHeader*)dtb;
 
     if (from_be32(dtb_header->magic) != DTB_MAGIC) {
@@ -136,10 +137,10 @@ void dtb_init(uintptr_t dtb, Allocator* alloc) {
         abort();
     }
 
-    dtb_parse(dtb_header, alloc);
+    return dtb_parse(dtb_header, alloc);
 }
 
-DTBNode* dtb_lookup(char const* name) {
+DTBNode* dtb_lookup(DTBNode* root, char const* name) {
     DTBNode* node = root->children;
 
     while (node->next != NULL) {
diff --git a/src/libs/dtb/mod.h b/src/libs/dtb/mod.h
index fb11ac8..6157f76 100644
--- a/src/libs/dtb/mod.h
+++ b/src/libs/dtb/mod.h
@@ -40,6 +40,6 @@ typedef struct _DTBNode {
     struct _DTBNode* parent;
 } DTBNode;
 
-void dtb_init(uintptr_t dtb, Allocator* alloc);
+DTBNode* dtb_init(uintptr_t dtb, Allocator* alloc);
 
-DTBNode* dtb_lookup(char const* name);
+DTBNode* dtb_lookup(DTBNode* root, char const* name);