From f4300c72549b313f12811c0563bca494d62340cb Mon Sep 17 00:00:00 2001
From: Stathis Kamperis <ekamperi@gmail.com>
Date: Sun, 17 Feb 2008 23:54:47 +0200
Subject: [PATCH] Initial import of minimal character device driver based on
 Brett's Lymn contributions

---
 cdev/mydev.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 cdev/mydev.h | 28 +++++++++++++++++++
 cdev/test.c  | 27 +++++++++++++++++++
 3 files changed, 142 insertions(+)
 create mode 100644 cdev/mydev.c
 create mode 100644 cdev/mydev.h
 create mode 100644 cdev/test.c

diff --git a/cdev/mydev.c b/cdev/mydev.c
new file mode 100644
index 0000000..4ec652b
--- /dev/null
+++ b/cdev/mydev.c
@@ -0,0 +1,87 @@
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/errno.h>
+#include <sys/ioctl.h>
+#include <sys/device.h>
+#include <sys/conf.h>
+#include <sys/mydev.h>
+
+struct mydev_softc {
+	struct device	mydev_dev;
+};
+
+/* Autoconfiguration glue */
+void	mydevattach(struct device *parent, struct device *self, void *aux);
+int     mydevopen(dev_t device, int flags, int fmt, struct lwp *process);
+int     mydevclose(dev_t device, int flags, int fmt, struct lwp *process);
+int     mydevioctl(dev_t device, u_long command, caddr_t data,
+		      int flags, struct lwp *process);
+
+/* just define the character device handlers because that is all we need */
+const struct cdevsw mydev_cdevsw = {
+        mydevopen,
+	mydevclose,
+	noread,
+	nowrite,
+        mydevioctl,
+	nostop,
+	notty,
+	nopoll,
+	nommap,
+	nokqfilter,
+        0 /* int d_type; */
+};
+
+/*
+ * Attach for autoconfig to find.
+ */
+void
+mydevattach(struct device *parent, struct device *self, void *aux)
+{
+	  /* nothing to do for mydev, this is where resources that
+	     need to be allocated/initialised before open is called
+	     can be set up */
+}
+
+/*
+ * Handle an open request on the device.
+ */
+int
+mydevopen(dev_t device, int flags, int fmt, struct lwp *process)
+{
+	return 0; /* this always succeeds */
+}
+
+/*
+ * Handle the close request for the device.
+ */
+int
+mydevclose(dev_t device, int flags, int fmt, struct lwp *process)
+{
+	return 0; /* again this always succeeds */
+}
+
+/*
+ * Handle the ioctl for the device
+ */
+int
+mydevioctl(dev_t device, u_long command, caddr_t data, int flags,
+	      struct lwp *process)
+{
+	int error;
+	struct mydev_params *params = (struct mydev_params *)data;
+
+	error = 0;
+	switch (command) {
+		case MYDEVTEST:
+			printf("Got number of %d and string of %s\n",
+			       params->number, params->string);
+			break;
+
+		default:
+			error = ENODEV;
+	}
+
+	return (error);
+}
diff --git a/cdev/mydev.h b/cdev/mydev.h
new file mode 100644
index 0000000..7eca045
--- /dev/null
+++ b/cdev/mydev.h
@@ -0,0 +1,28 @@
+/*
+ *
+ * Definitions for the Mydev pseudo device.
+ *
+ */
+#include <sys/param.h>
+#include <sys/device.h>
+
+#ifndef MYDEV_H
+#define MYDEV_H 1
+
+struct mydev_params
+{
+	int number;
+	char string[80];
+};
+
+#define MYDEVTEST _IOW('S', 0x1, struct mydev_params)
+
+#ifdef _KERNEL
+
+/*
+ * Put kernel inter-module interfaces here, this
+ * pseudo device has none.
+ */
+
+#endif
+#endif
diff --git a/cdev/test.c b/cdev/test.c
new file mode 100644
index 0000000..4030152
--- /dev/null
+++ b/cdev/test.c
@@ -0,0 +1,27 @@
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/mydev.h>
+
+int main()
+{
+    struct mydev_params params;
+    int mydev_dev;
+
+    params.number = 42;
+    strcpy(params.string, "Hello World");
+
+    if ((mydev_dev = open("/dev/mydev", O_RDONLY, 0)) < 0) {
+        fprintf(stderr, "Failed to open /dev/skel\n");
+        exit(2);
+    }
+
+    if (ioctl(mydev_dev, MYDEVTEST, &params) < 0) {
+        perror("ioctl failed");
+        exit(2);
+    }
+    
+    exit(0);
+}
-- 
2.11.4.GIT