kern: Introduce clock device framework

This commit introduces a new framework we call "clkdev". It is used to
keep track of the clock sources on the system and be able to fetch them
later based on specific attributes.

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

1 files changed, 77 insertions, 0 deletions

diff --git a/src/sys/os/os_clkdev.c b/src/sys/os/os_clkdev.c
new file mode 100644
index 0000000..4a1d4cc
--- /dev/null
+++ b/src/sys/os/os_clkdev.c
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * 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 the project 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/errno.h>
+#include <os/clkdev.h>
+#include <os/spinlock.h>
+
+static uint8_t nclk = 0;
+static struct clkdev *clklist[MAX_CLKDEV];
+static struct spinlock lock;
+
+/*
+ * Register a clock device
+ */
+int
+clkdev_register(struct clkdev *clkdev)
+{
+    if (clkdev == NULL) {
+        return -EINVAL;
+    }
+
+    if (nclk >= MAX_CLKDEV) {
+        return -ENOSPC;
+    }
+
+    spinlock_acquire(&lock);
+    clklist[nclk++] = clkdev;
+    spinlock_release(&lock);
+    return 0;
+}
+
+/*
+ * Get a specific clock device from index
+ */
+int
+clkdev_get(uint16_t attr, struct clkdev **clkdev_res)
+{
+    if (clkdev_res == NULL) {
+        return -EINVAL;
+    }
+
+    /* Must find one that matches 'attr' */
+    for (int i = 0; i < MAX_CLKDEV; ++i) {
+        if (clklist[i]->attr == attr) {
+            *clkdev_res = clklist[i];
+            return 0;
+        }
+    }
+
+    return -1;
+}