X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=include%2Flinux%2Fscatterlist.h;h=45712317138973ad8147ed0567c30bb4d62da55a;hb=7f1495745347bc2cb9cc4f50d0a889caeb71f1f1;hp=c6136e8a7f58fcb561ffc042b501e7a9f554c1a1;hpb=18dabf473e15850c0dbc8ff13ac1e2806d542c15;p=pandora-kernel.git

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index c6136e8a7f58..457123171389 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -1,6 +1,7 @@
 #ifndef _LINUX_SCATTERLIST_H
 #define _LINUX_SCATTERLIST_H
 
+#include <asm/types.h>
 #include <asm/scatterlist.h>
 #include <linux/mm.h>
 #include <linux/string.h>
@@ -23,10 +24,39 @@
  *
  */
 
+#define SG_MAGIC	0x87654321
+
+/**
+ * sg_assign_page - Assign a given page to an SG entry
+ * @sg:		    SG entry
+ * @page:	    The page
+ *
+ * Description:
+ *   Assign page to sg entry. Also see sg_set_page(), the most commonly used
+ *   variant.
+ *
+ **/
+static inline void sg_assign_page(struct scatterlist *sg, struct page *page)
+{
+	unsigned long page_link = sg->page_link & 0x3;
+
+	/*
+	 * In order for the low bit stealing approach to work, pages
+	 * must be aligned at a 32-bit boundary as a minimum.
+	 */
+	BUG_ON((unsigned long) page & 0x03);
+#ifdef CONFIG_DEBUG_SG
+	BUG_ON(sg->sg_magic != SG_MAGIC);
+#endif
+	sg->page_link = page_link | (unsigned long) page;
+}
+
 /**
  * sg_set_page - Set sg entry to point at given page
  * @sg:		 SG entry
  * @page:	 The page
+ * @len:	 Length of data
+ * @offset:	 Offset into page
  *
  * Description:
  *   Use this function to set an sg entry pointing at a page, never assign
@@ -35,11 +65,12 @@
  *   to an sg entry.
  *
  **/
-static inline void sg_set_page(struct scatterlist *sg, struct page *page)
+static inline void sg_set_page(struct scatterlist *sg, struct page *page,
+			       unsigned int len, unsigned int offset)
 {
-	unsigned long page_link = sg->page_link & 0x3;
-
-	sg->page_link = page_link | (unsigned long) page;
+	sg_assign_page(sg, page);
+	sg->offset = offset;
+	sg->length = len;
 }
 
 #define sg_page(sg)	((struct page *) ((sg)->page_link & ~0x3))
@@ -54,9 +85,7 @@ static inline void sg_set_page(struct scatterlist *sg, struct page *page)
 static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
 			      unsigned int buflen)
 {
-	sg_set_page(sg, virt_to_page(buf));
-	sg->offset = offset_in_page(buf);
-	sg->length = buflen;
+	sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
 }
 
 /*
@@ -81,6 +110,9 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
  **/
 static inline struct scatterlist *sg_next(struct scatterlist *sg)
 {
+#ifdef CONFIG_DEBUG_SG
+	BUG_ON(sg->sg_magic != SG_MAGIC);
+#endif
 	if (sg_is_last(sg))
 		return NULL;
 
@@ -123,6 +155,10 @@ static inline struct scatterlist *sg_last(struct scatterlist *sgl,
 	for_each_sg(sgl, sg, nents, i)
 		ret = sg;
 
+#endif
+#ifdef CONFIG_DEBUG_SG
+	BUG_ON(sgl[0].sg_magic != SG_MAGIC);
+	BUG_ON(!sg_is_last(ret));
 #endif
 	return ret;
 }
@@ -180,6 +216,9 @@ static inline void sg_init_one(struct scatterlist *sg, const void *buf,
 			       unsigned int buflen)
 {
 	memset(sg, 0, sizeof(*sg));
+#ifdef CONFIG_DEBUG_SG
+	sg->sg_magic = SG_MAGIC;
+#endif
 	sg_mark_end(sg, 1);
 	sg_set_buf(sg, buf, buflen);
 }
@@ -198,6 +237,13 @@ static inline void sg_init_table(struct scatterlist *sgl, unsigned int nents)
 {
 	memset(sgl, 0, sizeof(*sgl) * nents);
 	sg_mark_end(sgl, nents);
+#ifdef CONFIG_DEBUG_SG
+	{
+		int i;
+		for (i = 0; i < nents; i++)
+			sgl[i].sg_magic = SG_MAGIC;
+	}
+#endif
 }
 
 /**
@@ -210,7 +256,7 @@ static inline void sg_init_table(struct scatterlist *sgl, unsigned int nents)
  *   on the sg page.
  *
  **/
-static inline unsigned long sg_phys(struct scatterlist *sg)
+static inline dma_addr_t sg_phys(struct scatterlist *sg)
 {
 	return page_to_phys(sg_page(sg)) + sg->offset;
 }