Linux Device Drivers 3 examples

1 files changed, 49 insertions, 0 deletions

diff --git a/snull/snull.h b/snull/snull.h
new file mode 100644
index 0000000..69a49a0
--- /dev/null
+++ b/snull/snull.h
@@ -0,0 +1,49 @@
+
+/*
+ * snull.h -- definitions for the network module
+ *
+ * Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
+ * Copyright (C) 2001 O'Reilly & Associates
+ *
+ * The source code in this file can be freely used, adapted,
+ * and redistributed in source or binary form, so long as an
+ * acknowledgment appears in derived source files.  The citation
+ * should list that the code comes from the book "Linux Device
+ * Drivers" by Alessandro Rubini and Jonathan Corbet, published
+ * by O'Reilly & Associates.   No warranty is attached;
+ * we cannot take responsibility for errors or fitness for use.
+ */
+
+/*
+ * Macros to help debugging
+ */
+
+#undef PDEBUG             /* undef it, just in case */
+#ifdef SNULL_DEBUG
+#  ifdef __KERNEL__
+     /* This one if debugging is on, and kernel space */
+#    define PDEBUG(fmt, args...) printk( KERN_DEBUG "snull: " fmt, ## args)
+#  else
+     /* This one for user space */
+#    define PDEBUG(fmt, args...) fprintf(stderr, fmt, ## args)
+#  endif
+#else
+#  define PDEBUG(fmt, args...) /* not debugging: nothing */
+#endif
+
+#undef PDEBUGG
+#define PDEBUGG(fmt, args...) /* nothing: it's a placeholder */
+
+
+/* These are the flags in the statusword */
+#define SNULL_RX_INTR 0x0001
+#define SNULL_TX_INTR 0x0002
+
+/* Default timeout period */
+#define SNULL_TIMEOUT 5   /* In jiffies */
+
+extern struct net_device *snull_devs[];
+
+
+
+