patch-2.4.22 linux-2.4.22/arch/cris/drivers/examples/kiobuftest.c

• Lines: 138
• Date: 2003-08-25 04:44:39.000000000 -0700
• Orig file: linux-2.4.21/arch/cris/drivers/examples/kiobuftest.c
• Orig date: 2001-04-06 10:42:55.000000000 -0700

diff -urN linux-2.4.21/arch/cris/drivers/examples/kiobuftest.c linux-2.4.22/arch/cris/drivers/examples/kiobuftest.c
@@ -4,18 +4,12 @@
  *
  * It is necessary because the pages the virtual pointers reference, might
  * not exist in memory (could be mapped to the zero-page, filemapped etc)
- * and DMA cannot trigger the MMU to force them in (and would have time 
+ * and DMA cannot trigger the MMU to force them in (and would have time
  * contraints making it impossible to wait for it anyway).
  *
- * Author:  Bjorn Wesen
- *
- * $Log: kiobuftest.c,v $
- * Revision 1.2  2001/02/27 13:52:50  bjornw
- * malloc.h -> slab.h
- *
- * Revision 1.1  2001/01/19 15:57:49  bjornw
- * Example of how to do direct HW -> user-mode DMA
+ * Copyright (c) 2001, 2002, 2003  Axis Communications AB
  *
+ * Author:  Bjorn Wesen
  *
  */
 
@@ -32,55 +26,55 @@
 
 #define KIOBUFTEST_MAJOR 124  /* in the local range, experimental */
 
-
 static ssize_t
 kiobuf_read(struct file *filp, char *buf, size_t len, loff_t *ppos)
 {
+	struct kiobuf *iobuf;
+	int res, i;
 
-     struct kiobuf *iobuf;
-     int res, i;
- 
-     /* Make a kiobuf that maps the entire length the reader has given
-      * us
-      */
-
-     res = alloc_kiovec(1, &iobuf);
-     if (res)
-	     return res;
-     
-     if((res = map_user_kiobuf(READ, iobuf, (unsigned long)buf, len))) {
-	     printk("map_user_kiobuf failed, return %d\n", res);
-	     return res;
-     }
-
-     /* At this point, the virtual area buf[0] -> buf[len-1] will
-      * have corresponding pages mapped in physical memory and locked
-      * until we unmap the kiobuf. They cannot be swapped out or moved
-      * around.
-      */
-
-     printk("nr_pages == %d\noffset == %d\nlength == %d\n",
-	    iobuf->nr_pages, iobuf->offset, iobuf->length);
-
-     for(i = 0; i < iobuf->nr_pages; i++) {
-	     printk("page_add(maplist[%d]) == 0x%x\n", i,
-		    page_address(iobuf->maplist[i]));
-     }
-
-     /* This is the place to create the necessary scatter-gather vector
-      * for the DMA using the iobuf->maplist array and page_address
-      * (don't forget __pa if the DMA needs the actual physical DRAM address)
-      * and run it.
-      */
+	/*
+	 * Make a kiobuf that maps the entire length the reader has given us.
+	 */
 
+	res = alloc_kiovec(1, &iobuf);
+	if (res)
+		return res;
+
+	if ((res = map_user_kiobuf(READ, iobuf, (unsigned long)buf, len))) {
+		printk("map_user_kiobuf failed, return %d\n", res);
+		free_kiovec(1, &iobuf);
+		return res;
+	}
+
+	/*
+	 * At this point, the virtual area buf[0] -> buf[len-1] will have
+	 * corresponding pages mapped in physical memory and locked until
+	 * we unmap the kiobuf. They cannot be swapped out or moved around.
+	 */
+
+	printk("nr_pages == %d\noffset == %d\nlength == %d\n",
+	       iobuf->nr_pages, iobuf->offset, iobuf->length);
+
+	for (i = 0; i < iobuf->nr_pages; i++) {
+		printk("page_add(maplist[%d]) == 0x%x\n", i,
+		       page_address(iobuf->maplist[i]));
+	}
+
+	/*
+	 * This is the place to create the necessary scatter-gather vector
+	 * for the DMA using the iobuf->maplist array and page_address (don't
+	 * forget __pa if the DMA needs the actual physical DRAM address)
+	 * and run it.
+	 */
 
 
 
-     /* Release the mapping and exit */
+	/* Release the mapping and exit */
 
-     unmap_kiobuf(iobuf); /* The unlock_kiobuf is implicit here */
+	unmap_kiobuf(iobuf); /* The unlock_kiobuf is implicit here */
+	free_kiovec(1, &iobuf);
 
-     return len;
+	return len;
 }
 
 
@@ -97,7 +91,7 @@
 	/* register char device */
 
 	res = register_chrdev(KIOBUFTEST_MAJOR, "kiobuftest", &kiobuf_fops);
-	if(res < 0) {
+	if (res < 0) {
 		printk(KERN_ERR "kiobuftest: couldn't get a major number.\n");
 		return res;
 	}
@@ -105,4 +99,11 @@
 	printk("Initializing kiobuf-test device\n");
 }
 
+static void __exit
+kiobuftest_exit(void)
+{
+	unregister_chrdev(KIOBUFTEST_MAJOR, "kiobuftest");
+}
+
 module_init(kiobuftest_init);
+module_exit(kiobuftest_exit);