Shuffle around directories

README.md

@@ -2,13 +2,21 @@
 
 This is my custom kernel for learning purposes. I'm not a osdev at all, so please excuse the mess.
 
-Right now it compiles for x86_64, 32-bit is not supported. Most of this is just skeleton code from osdev.org, but I cleaned
+Right now it compiles for `x86_64`, 32-bit is not supported. Most of this is just skeleton code from osdev.org, but I cleaned
 some stuff. I use Stivale for higher half kernel loading and not having to gaff about a bootloader for now. Limine is included
 as my bootloader of choice.
 
+## Organization
+
+This file organization is definitely not final, and will be shuffled around as sen is developed. Currently it is:
+* `src/` - All of the source files for sen, including ld configs etc.
+  * `boot/` - Bootloader-related sources and entrypoints.
+  * `drivers/` - Drivers for specific subsystems in the kernel, such as tty drivers.
+  * `kernel/` - Vendor-agnostic stuff like the actual loop, the startup sequence, etc. This also contains the public kernel interface.
+
 ## Building
 
-Currently it requires GNU make, and some version of GCC. If you wish to build the iso, you also need xorriso.
+Currently, sen requires GNU make, and some version of GCC. If you wish to build the iso, you also need xorriso.
 
 Run make to build the elf:
 

src/boot/stivale/stivale.c

@@ -1,6 +1,5 @@
-#include <stdint.h>
-#include <stddef.h>
-#include <stivale2.h>
+#include <boot/stivale/stivale.h>
+#include <kernel/kernel.h>
 
 // We need to tell the stivale bootloader where we want our stack to be.
 // We are going to allocate our stack as an array in .bss.
@@ -76,45 +75,12 @@ static struct stivale2_header stivale_hdr = {
     // points to the first one in the linked list.
     .tags = (uintptr_t)&framebuffer_hdr_tag
 };
- 
-// We will now write a helper function which will allow us to scan for tags
-// that we want FROM the bootloader (structure tags).
-void *stivale2_get_tag(struct stivale2_struct *stivale2_struct, uint64_t id) {
-    struct stivale2_tag *current_tag = (void *)stivale2_struct->tags;
-    for (;;) {
-        // If the tag pointer is NULL (end of linked list), we did not find
-        // the tag. Return NULL to signal this.
-        if (current_tag == NULL) {
-            return NULL;
-        }
- 
-        // Check whether the identifier matches. If it does, return a pointer
-        // to the matching tag.
-        if (current_tag->identifier == id) {
-            return current_tag;
-        }
- 
-        // Get a pointer to the next tag in the linked list and repeat.
-        current_tag = (void *)current_tag->next;
-    }
-}
 
-struct stivale2_struct_tag_terminal *term_str_tag = NULL;
-void *term_write_ptr = NULL;
-void (*term_write)(const char *string, size_t length) = NULL;
+struct stivale2_struct *stivale2_struct;
 
 // The following will be our kernel's entry point.
-void _start(struct stivale2_struct *stivale2_struct) {
-    // Let's get the terminal structure tag from the bootloader.
-    term_str_tag = stivale2_get_tag(stivale2_struct, STIVALE2_STRUCT_TAG_TERMINAL_ID);
- 
-    // Check if the tag was actually found.
-    if (term_str_tag == NULL) {
-        // It wasn't found, just hang...
-        for (;;) {
-            asm ("hlt");
-        }
-    }
+void _start(struct stivale2_struct *in) {
+    stivale2_struct = in;
  
     kernel_main();
     
@@ -122,19 +88,4 @@ void _start(struct stivale2_struct *stivale2_struct) {
     for (;;) {
         asm ("hlt");
     }
-}
-
-void terminal_initialize() {
-  // stub for stivale
-  // Let's get the address of the terminal write function.
-    term_write_ptr = (void *)term_str_tag->term_write;
- 
-    // Now, let's assign this pointer to a function pointer which
-    // matches the prototype described in the stivale2 specification for
-    // the stivale2_term_write function.
-    term_write = term_write_ptr;
-}
-
-void tty_print(const char* str, int length) {
-    term_write(str, length);
-}
+}

src/boot/stivale/stivale.h

@@ -0,0 +1,10 @@
+#ifndef _BOOT_STIVALE_H
+#define _BOOT_STIVALE_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stivale2.h>
+
+extern struct stivale2_struct *stivale2_struct;
+
+#endif

src/drivers/tty/stivale.c

@@ -0,0 +1,49 @@
+#include <boot/stivale/stivale.h>
+#include <kernel/tty/tty.h>
+
+// We will now write a helper function which will allow us to scan for tags
+// that we want FROM the bootloader (structure tags).
+void *stivale2_get_tag(struct stivale2_struct *stivale2_struct, uint64_t id) {
+    struct stivale2_tag *current_tag = (void *)stivale2_struct->tags;
+    for (;;) {
+        // If the tag pointer is NULL (end of linked list), we did not find
+        // the tag. Return NULL to signal this.
+        if (current_tag == NULL) {
+            return NULL;
+        }
+
+        // Check whether the identifier matches. If it does, return a pointer
+        // to the matching tag.
+        if (current_tag->identifier == id) {
+            return current_tag;
+        }
+
+        // Get a pointer to the next tag in the linked list and repeat.
+        current_tag = (void *)current_tag->next;
+    }
+}
+
+struct stivale2_struct_tag_terminal *terminal_tag = NULL;
+
+// stivale function stubs
+void (*term_write)(const char *string, size_t length) = NULL;
+
+// for this driver we simply load all the function pointers from the terminal tag
+void terminal_initialize() {
+    terminal_tag = stivale2_get_tag(stivale2_struct, STIVALE2_STRUCT_TAG_TERMINAL_ID);
+
+    // Check if the tag was actually found.
+    if (terminal_tag == NULL) {
+        // It wasn't found, just hang...
+        for (;;) {
+            asm ("hlt");
+        }
+    }
+
+    // the address from this struct is uint64, so we must convert to a pointer
+    term_write = (void *)terminal_tag->term_write;
+}
+
+void tty_print(const char* str, int length) {
+    term_write(str, length);
+}

src/kernel.c

@@ -1,6 +0,0 @@
-#include <tty.h>
-
-void kernel_main(void) {
-  terminal_initialize();
-  tty_print("Hello, world!", 12);
-}

src/kernel/kernel.c

@@ -0,0 +1,9 @@
+#include <kernel/kernel.h>
+#include <kernel/tty/tty.h>
+
+void kernel_main(void) {
+    // initialize subsystems, currently only tty
+    terminal_initialize();
+
+    tty_print("Loading sen...", 15);
+}

src/kernel/kernel.h

@@ -0,0 +1,2 @@
+// this is the main kernel entrypoint
+void kernel_main(void);