powerpc/powernv: Move SG list structure to header file

Move SG list and entry structure to header file so that
it can be used in other places as well.

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/opal.h

@@ -33,6 +33,28 @@ struct opal_takeover_args {
 	u64	rd_loc;			/* r11 */
 };
 
+/*
+ * SG entry
+ *
+ * WARNING: The current implementation requires each entry
+ * to represent a block that is 4k aligned *and* each block
+ * size except the last one in the list to be as well.
+ */
+struct opal_sg_entry {
+	void    *data;
+	long    length;
+};
+
+/* sg list */
+struct opal_sg_list {
+	unsigned long num_entries;
+	struct opal_sg_list *next;
+	struct opal_sg_entry entry[];
+};
+
+/* We calculate number of sg entries based on PAGE_SIZE */
+#define SG_ENTRIES_PER_NODE ((PAGE_SIZE - 16) / sizeof(struct opal_sg_entry))
+
 extern long opal_query_takeover(u64 *hal_size, u64 *hal_align);
 
 extern long opal_do_takeover(struct opal_takeover_args *args);

arch/powerpc/platforms/powernv/opal-flash.c

@@ -103,27 +103,6 @@ struct image_header_t {
 	uint32_t	size;
 };
 
-/* Scatter/gather entry */
-struct opal_sg_entry {
-	void	*data;
-	long	length;
-};
-
-/* We calculate number of entries based on PAGE_SIZE */
-#define SG_ENTRIES_PER_NODE ((PAGE_SIZE - 16) / sizeof(struct opal_sg_entry))
-
-/*
- * This struct is very similar but not identical to that
- * needed by the opal flash update. All we need to do for
- * opal is rewrite num_entries into a version/length and
- * translate the pointers to absolute.
- */
-struct opal_sg_list {
-	unsigned long num_entries;
-	struct opal_sg_list *next;
-	struct opal_sg_entry entry[SG_ENTRIES_PER_NODE];
-};
-
 struct validate_flash_t {
 	int		status;		/* Return status */
 	void		*buf;		/* Candiate image buffer */
@@ -333,7 +312,7 @@ static struct opal_sg_list *image_data_to_sglist(void)
 	addr = image_data.data;
 	size = image_data.size;
 
-	sg1 = kzalloc((sizeof(struct opal_sg_list)), GFP_KERNEL);
+	sg1 = kzalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!sg1)
 		return NULL;
 
@@ -351,8 +330,7 @@ static struct opal_sg_list *image_data_to_sglist(void)
 
 		sg1->num_entries++;
 		if (sg1->num_entries >= SG_ENTRIES_PER_NODE) {
-			sg1->next = kzalloc((sizeof(struct opal_sg_list)),
-					    GFP_KERNEL);
+			sg1->next = kzalloc(PAGE_SIZE, GFP_KERNEL);
 			if (!sg1->next) {
 				pr_err("%s : Failed to allocate memory\n",
 				       __func__);
@@ -402,7 +380,10 @@ static int opal_flash_update(int op)
 		else
 			sg->next = NULL;
 
-		/* Make num_entries into the version/length field */
+		/*
+		 * Convert num_entries to version/length format
+		 * to satisfy OPAL.
+		 */
 		sg->num_entries = (SG_LIST_VERSION << 56) |
 			(sg->num_entries * sizeof(struct opal_sg_entry) + 16);
 	}