dev: start implementing framebuffer devices

dev/fb.c

@@ -0,0 +1,47 @@
+#include <socks/device.h>
+#include <socks/bitmap.h>
+#include <socks/libc/stdio.h>
+
+static DECLARE_BITMAP(fb_device_ids, FRAMEBUFFER_DEVICE_MAX);
+static spin_lock_t fb_device_ids_lock = SPIN_LOCK_INIT;
+
+struct framebuffer_device *framebuffer_device_create(void)
+{
+	struct device *dev = device_alloc();
+	if (!dev) {
+		return NULL;
+	}
+
+	dev->dev_type = DEV_TYPE_FRAMEBUFFER;
+
+	return FRAMEBUFFER_DEVICE(dev);
+}
+
+static kern_status_t generate_name(struct framebuffer_device *dev, char out[DEV_NAME_MAX])
+{
+	snprintf(out, DEV_NAME_MAX, "fb%u", dev->fb_id);
+	return KERN_OK;
+}
+
+kern_status_t framebuffer_device_register(struct device *dev)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&fb_device_ids_lock, &flags);
+	unsigned int id = bitmap_lowest_clear(fb_device_ids, INPUT_DEVICE_MAX);
+	bitmap_set(fb_device_ids, id);
+	spin_unlock_irqrestore(&fb_device_ids_lock, flags);
+
+	struct framebuffer_device *fbdev = &dev->fb;
+	fbdev->fb_id = id;
+
+	char name[DEV_NAME_MAX];
+	generate_name(fbdev, name);
+	char path[OBJECT_PATH_MAX];
+	snprintf(path, sizeof path, "/dev/video/%s", name);
+
+	return object_namespace_create_link(global_namespace(), path, &dev->dev_base);
+}
+
+struct device_type_ops framebuffer_type_ops = {
+	.register_device = framebuffer_device_register,
+};