kernel: device: Add read/write stubs

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

2 files changed, 55 insertions, 0 deletions

diff --git a/sys/include/sys/device.h b/sys/include/sys/device.h
index e0aef23..b1de7d3 100644
--- a/sys/include/sys/device.h
+++ b/sys/include/sys/device.h
@@ -40,6 +40,10 @@
 typedef uint8_t devmajor_t;
 typedef uint8_t dev_t;
 
+/* Device operation typedefs */
+typedef int(*dev_read_t)(dev_t, struct sio_txn *, int);
+typedef int(*dev_write_t)(dev_t, struct sio_txn *, int);
+
 struct cdevsw {
     int(*read)(dev_t dev, struct sio_txn *sio, int flags);
     int(*write)(dev_t dev, struct sio_txn *sio, int flags);
@@ -56,5 +60,12 @@ dev_t dev_alloc(devmajor_t major);
 devmajor_t dev_alloc_major(void);
 int dev_register(devmajor_t major, dev_t dev, void *devsw);
 
+int dev_noread(void);
+int dev_nowrite(void);
+
+/* Device operation stubs */
+#define noread ((dev_read_t)dev_noread)
+#define nowrite ((dev_write_t)dev_nowrite)
+
 #endif  /* _KERNEL */
 #endif  /* !_SYS_DEVICE_H_ */
diff --git a/sys/kern/kern_stub.c b/sys/kern/kern_stub.c
new file mode 100644
index 0000000..65688e2
--- /dev/null
+++ b/sys/kern/kern_stub.c
@@ -0,0 +1,44 @@
+/*
+ * 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/types.h>
+#include <sys/errno.h>
+
+int
+dev_noread(void)
+{
+    return -ENOTSUP;
+}
+
+int
+dev_nowrite(void)
+{
+    return -ENOTSUP;
+}