1 files changed, 43 insertions, 1 deletions
diff --git a/main.c b/main.c
index fcd5732..0ea47c8 100644
--- a/main.c
+++ b/main.c
@@ -1,4 +1,5 @@
-/* main.c
+/*
+ * main.c
  *
  * r/w /dev/helloc0 character device
  *
@@ -16,6 +17,10 @@
  * - ssize_t is an int, size_t is unsigned int, be careful
  * - compile kernel with frame pointers to get better stack readout in case of an oops
  *
+ * coding standars:
+ * - kernel official doc calls for tabs of width of 8, I'm using 4 spaced tab
+ * - ToDo: run Lindent
+ *
  */
 
 #include <linux/module.h>
@@ -27,6 +32,7 @@
 #include <linux/fs.h>
 #include <linux/cdev.h>
 #include <asm/uaccess.h> /* copy_*_user */
+#include <linux/proc_fs.h>
 
 #include <main.h>
 #include <debug.h>
@@ -42,6 +48,34 @@ struct dentry *debugfs_file = NULL;
 
 struct hello_dev *hello_device;
 
+/*
+ * Use proc filesystem only when we are debugging, since it is discouraged in
+ * favor of sys filesystem
+ */
+#ifdef HELLO_DEBUG
+
+/*
+ * The proc filesystem is there to allow us to tap into driver's internal data
+ * structure within a kernel, in our case it will be struct hello_buffer
+ */
+static void hello_create_proc(void)
+{
+    /* below function returns a proc_dir_entry that we will ignore, it's ok
+     * proc_root in fs/proc/root.c:249 is a static variable that will have a
+     * link to our raed entry
+     */
+    create_proc_read_entry("hellomem", 0 /* default mode */, NULL /* parent dir */,
+            hello_read_procmem /* function ptr to our read method */,
+            hello_device /* our dev struct that kernel will pass for us that we will access */);
+}
+
+static void hello_remove_proc(void)
+{
+    remove_proc_entry("hellomem", NULL);
+}
+
+#endif
+
 static int hello_create_debugfs(void)
 {
     int ret = 0;
@@ -54,6 +88,8 @@ static int hello_create_debugfs(void)
     return ret;
 }
 
+
+
 static ssize_t hello_read(struct file *filp, char __user *buff, size_t count, loff_t *f_pos)
 {
     struct hello_dev *dev = filp->private_data;
@@ -185,6 +221,9 @@ static int __init hello_init(void)
     }
 
     hello_create_debugfs();
+#ifdef HELLO_DEBUG
+    hello_create_proc();
+#endif
 
     return 0;
 
@@ -197,6 +236,9 @@ static void __exit hello_exit(void)
 {
     unregister_chrdev_region(MKDEV(hello_major, hello_minor), 1);
     hello_debugfs_destroy(debugfs_dir, debugfs_file);
+#ifdef HELLO_DEBUG
+    hello_remove_proc();
+#endif
     printk(KERN_INFO "[hello] module removed\n");
 }