From 265d015c932772bdfc67ea1058188f21dc93ed04 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Thu, 18 Apr 2024 15:09:17 -0400
Subject: kernel: fbdev: Create fbdev device file

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 sys/dev/video/fbdev.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/sys/dev/video/fbdev.c b/sys/dev/video/fbdev.c
index 326f548..70031a0 100644
--- a/sys/dev/video/fbdev.c
+++ b/sys/dev/video/fbdev.c
@@ -29,7 +29,11 @@
 
 #include <sys/types.h>
 #include <sys/limine.h>
+#include <sys/device.h>
+#include <sys/driver.h>
 #include <dev/video/fbdev.h>
+#include <vm/vm.h>
+#include <fs/devfs.h>
 
 #define FRAMEBUFFER \
         framebuffer_req.response->framebuffers[0]
@@ -39,6 +43,23 @@ static volatile struct limine_framebuffer_request framebuffer_req = {
     .revision = 0
 };
 
+static struct device *dev;
+
+static paddr_t
+fbdev_mmap(struct device *dev, off_t off, vm_prot_t prot)
+{
+    struct fbdev fbdev = fbdev_get_front();
+    paddr_t len = fbdev.width * fbdev.pitch;
+    paddr_t base = VIRT_TO_PHYS(fbdev.mem);
+    paddr_t max_paddr = base + len;
+
+    if (base + off > max_paddr) {
+        return 0;
+    }
+
+    return base + off;
+}
+
 struct fbdev
 fbdev_get_front(void)
 {
@@ -49,5 +70,20 @@ fbdev_get_front(void)
     ret.height = FRAMEBUFFER->height;
     ret.pitch = FRAMEBUFFER->pitch;
     return ret;
+}
 
+static int
+fbdev_init(void)
+{
+    dev = DEVICE_ALLOC();
+    dev->blocksize = 1;
+    dev->read = NULL;
+    dev->write = NULL;
+    dev->mmap = fbdev_mmap;
+
+    device_create(dev, device_alloc_major(), 1);
+    devfs_add_dev("fb", dev);
+    return 0;
 }
+
+DRIVER_EXPORT(fbdev_init);
-- 
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