增加了LLD3书中的代码...

linux_device_driver_v3/snull/Makefile

@@ -0,0 +1,41 @@
+# Comment/uncomment the following line to disable/enable debugging
+#DEBUG = y
+
+
+# Add your debugging flag (or not) to CFLAGS
+ifeq ($(DEBUG),y)
+  DEBFLAGS = -O -g -DSBULL_DEBUG # "-O" is needed to expand inlines
+else
+  DEBFLAGS = -O2
+endif
+
+CFLAGS += $(DEBFLAGS)
+CFLAGS += -I..
+
+ifneq ($(KERNELRELEASE),)
+# call from kernel build system
+
+obj-m	:= snull.o
+
+else
+
+KERNELDIR ?= /lib/modules/$(shell uname -r)/build
+PWD       := $(shell pwd)
+
+default:
+	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
+
+endif
+
+
+
+clean:
+	rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions
+
+depend .depend dep:
+	$(CC) $(CFLAGS) -M *.c > .depend
+
+
+ifeq (.depend,$(wildcard .depend))
+include .depend
+endif