From 85aaf83ec18acfffd7ecd6b4df94ab66c83a40d3 Mon Sep 17 00:00:00 2001
From: Matheus <matheusuky@gmail.com>
Date: Sun, 9 Apr 2023 18:58:11 -0300
Subject: [PATCH] kernel: term

---
 kernel-src/arch/x86-64/main.c    |  2 ++
 kernel-src/include/kernel/term.h |  8 ++++++
 kernel-src/io/fb.c               |  6 ++++
 kernel-src/io/term.c             | 49 ++++++++++++++++++++++++++++++++
 4 files changed, 65 insertions(+)
 create mode 100644 kernel-src/include/kernel/term.h
 create mode 100644 kernel-src/io/fb.c
 create mode 100644 kernel-src/io/term.c

diff --git a/kernel-src/arch/x86-64/main.c b/kernel-src/arch/x86-64/main.c
index 6184279e..c7086592 100644
--- a/kernel-src/arch/x86-64/main.c
+++ b/kernel-src/arch/x86-64/main.c
@@ -3,6 +3,7 @@
 #include <arch/cpu.h>
 #include <arch/gdt.h>
 #include <arch/idt.h>
+#include <kernel/term.h>
 
 static cpu_t bsp_cpu;
 
@@ -12,5 +13,6 @@ void kernel_entry() {
 	arch_gdt_reload();
 	arch_idt_setup();
 	arch_idt_reload();
+	term_init();
 	__assert(!"kernel entry end");
 }
diff --git a/kernel-src/include/kernel/term.h b/kernel-src/include/kernel/term.h
new file mode 100644
index 00000000..7e9ddfd7
--- /dev/null
+++ b/kernel-src/include/kernel/term.h
@@ -0,0 +1,8 @@
+#ifndef _TERM_H
+#define _TERM_H
+
+void term_init();
+void term_putchar(char c);
+void term_write(char *str, size_t count);
+
+#endif
diff --git a/kernel-src/io/fb.c b/kernel-src/io/fb.c
new file mode 100644
index 00000000..96231d73
--- /dev/null
+++ b/kernel-src/io/fb.c
@@ -0,0 +1,6 @@
+#include <limine.h>
+
+volatile struct limine_framebuffer_request fb_liminereq = {
+	.id = LIMINE_FRAMEBUFFER_REQUEST,
+	.revision = 0
+};
diff --git a/kernel-src/io/term.c b/kernel-src/io/term.c
new file mode 100644
index 00000000..0ff7a14b
--- /dev/null
+++ b/kernel-src/io/term.c
@@ -0,0 +1,49 @@
+#include <flanterm.h>
+#include <backends/fb.h>
+#include <limine.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <printf.h>
+#include <logging.h>
+#include <string.h>
+
+#define EARLY_BUFFER_SIZE (64*1024*1024)
+
+extern volatile struct limine_framebuffer_request fb_liminereq;
+
+static size_t bufferused;
+static uint8_t allocbuffer[EARLY_BUFFER_SIZE];
+
+// TODO once the pmm is done, switch to allocating from it instead.
+// right now the terminal is supposed to be initialized before true memory management is initialized.
+// thus, there is a simple internal watermark allocator that allocates processor aligned chunks
+// of a buffer of size EARLY_BUFFER_SIZE
+static void *internalalloc(size_t n) {
+	__assert(bufferused + n <= EARLY_BUFFER_SIZE)
+	void *ret = &allocbuffer[bufferused];
+	bufferused += n + (sizeof(uintmax_t) - (n % sizeof(uintmax_t)));
+	return ret;
+}
+
+static struct flanterm_context *term_ctx;
+
+void term_write(char *str, size_t count) {
+	flanterm_write(term_ctx, str, count);
+}
+
+void term_putchar(char c) {
+	flanterm_write(term_ctx, &c, 1);
+}
+
+void term_init() {
+	__assert(fb_liminereq.response);
+	__assert(fb_liminereq.response->framebuffer_count);
+	struct limine_framebuffer *fb = fb_liminereq.response->framebuffers[0];
+
+	// TODO add support for a background if desired by the user
+	term_ctx = flanterm_fb_init(internalalloc, fb->address, fb->width, fb->height, fb->pitch,
+		NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+		0, 0, 1, 1, 1, 0);
+
+	__assert(term_ctx);
+}