kernel: Add device descriptors

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 84 insertions, 0 deletions

diff --git a/sys/kern/kern_device.c b/sys/kern/kern_device.c
new file mode 100644
index 0000000..cb9a6a1
--- /dev/null
+++ b/sys/kern/kern_device.c
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/device.h>
+#include <sys/queue.h>
+#include <sys/errno.h>
+#include <sys/types.h>
+#include <sys/spinlock.h>
+
+static TAILQ_HEAD(, device) devices;
+static struct spinlock devices_lock = {0};
+static bool device_list_init = false;
+
+dev_t
+device_alloc_major(void)
+{
+    static dev_t major = 1;
+    return major++;
+}
+
+struct device *
+device_fetch(dev_t major, dev_t minor)
+{
+    struct device *dev;
+
+    TAILQ_FOREACH(dev, &devices, link) {
+        if (dev->major == major && dev->minor == minor) {
+            return dev;
+        }
+    }
+
+    return NULL;
+}
+
+dev_t
+create_dev(struct device *dev, dev_t major, dev_t minor)
+{
+    if (dev == NULL || minor == 0) {
+        return -EINVAL;
+    }
+
+    if (major == 0) {
+        return -EINVAL;
+    }
+
+    if (!device_list_init) {
+        TAILQ_INIT(&devices);
+        device_list_init = true;
+    }
+
+    dev->major = major;
+    dev->minor = minor;
+
+    spinlock_acquire(&devices_lock);
+    TAILQ_INSERT_HEAD(&devices, dev, link);
+    spinlock_release(&devices_lock);
+    return dev->major;
+}