dev: start implementing framebuffer devices

kexts/drivers/video/vgafb/extension.yaml

@@ -0,0 +1,8 @@
+name: vgafb
+description: |
+  Generic VGA driver.
+id: net.doorstuck.socks.vgafb
+license: BSD-3-Clause
+copyright: Copyright © Max Wash 2023
+sources:
+  - main.c

kexts/drivers/video/vgafb/main.c

@@ -0,0 +1,36 @@
+#include <socks/printk.h>
+#include <socks/device.h>
+#include <socks/kext.h>
+#include <socks/libc/stdio.h>
+
+static struct driver *vga_driver = NULL;
+static struct framebuffer_device *vgafb = NULL;
+
+static kern_status_t online(struct kext *self)
+{
+	vga_driver = driver_create(self, "vgafb");
+	if (!vga_driver) {
+		return KERN_NO_MEMORY;
+	}
+
+	driver_register(vga_driver);
+
+	struct framebuffer_device *fb = framebuffer_device_create();
+	struct device *fb_base = framebuffer_device_base(fb);
+	snprintf(fb_base->dev_name, sizeof fb_base->dev_name, "vgafb");
+
+	kern_status_t status = device_register(fb_base, vga_driver, misc_device());
+	if (status != KERN_OK) {
+		driver_unregister(vga_driver);
+		driver_destroy(vga_driver);
+		return status;
+	}
+
+	vgafb = fb;
+
+	return KERN_OK;
+}
+
+DEFINE_KEXT("net.doorstuck.socks.vgafb",
+	    online, NULL,
+	    KEXT_NO_DEPENDENCIES);