#ifndef _LINUX_SCATTERLIST_H
#define _LINUX_SCATTERLIST_H
+#include <asm/types.h>
#include <asm/scatterlist.h>
#include <linux/mm.h>
#include <linux/string.h>
+#include <asm/io.h>
+struct sg_table {
+ struct scatterlist *sgl; /* the list */
+ unsigned int nents; /* number of mapped entries */
+ unsigned int orig_nents; /* original size of list */
+};
+
+/*
+ * Notes on SG table design.
+ *
+ * Architectures must provide an unsigned long page_link field in the
+ * scatterlist struct. We use that to place the page pointer AND encode
+ * information about the sg table as well. The two lower bits are reserved
+ * for this information.
+ *
+ * If bit 0 is set, then the page_link contains a pointer to the next sg
+ * table list. Otherwise the next entry is at sg + 1.
+ *
+ * If bit 1 is set, then this sg entry is the last element in a list.
+ *
+ * See sg_next().
+ *
+ */
+
+#define SG_MAGIC 0x87654321
+
+/*
+ * We overload the LSB of the page pointer to indicate whether it's
+ * a valid sg entry, or whether it points to the start of a new scatterlist.
+ * Those low bits are there for everyone! (thanks mason :-)
+ */
+#define sg_is_chain(sg) ((sg)->page_link & 0x01)
+#define sg_is_last(sg) ((sg)->page_link & 0x02)
+#define sg_chain_ptr(sg) \
+ ((struct scatterlist *) ((sg)->page_link & ~0x03))
+
+/**
+ * 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);
+ BUG_ON(sg_is_chain(sg));
+#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
+ * the page directly. We encode sg table information in the lower bits
+ * of the page pointer. See sg_page() for looking up the page belonging
+ * to an sg entry.
+ *
+ **/
+static inline void sg_set_page(struct scatterlist *sg, struct page *page,
+ unsigned int len, unsigned int offset)
+{
+ sg_assign_page(sg, page);
+ sg->offset = offset;
+ sg->length = len;
+}
+
+static inline struct page *sg_page(struct scatterlist *sg)
+{
+#ifdef CONFIG_DEBUG_SG
+ BUG_ON(sg->sg_magic != SG_MAGIC);
+ BUG_ON(sg_is_chain(sg));
+#endif
+ return (struct page *)((sg)->page_link & ~0x3);
+}
+
+/**
+ * sg_set_buf - Set sg entry to point at given data
+ * @sg: SG entry
+ * @buf: Data
+ * @buflen: Data length
+ *
+ **/
static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
unsigned int buflen)
{
- sg->page = 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));
}
-static inline void sg_init_one(struct scatterlist *sg, const void *buf,
- unsigned int buflen)
+/*
+ * Loop over each sg element, following the pointer to a new list if necessary
+ */
+#define for_each_sg(sglist, sg, nr, __i) \
+ for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg))
+
+/**
+ * sg_chain - Chain two sglists together
+ * @prv: First scatterlist
+ * @prv_nents: Number of entries in prv
+ * @sgl: Second scatterlist
+ *
+ * Description:
+ * Links @prv@ and @sgl@ together, to form a longer scatterlist.
+ *
+ **/
+static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
+ struct scatterlist *sgl)
{
- memset(sg, 0, sizeof(*sg));
- sg_set_buf(sg, buf, buflen);
+#ifndef ARCH_HAS_SG_CHAIN
+ BUG();
+#endif
+
+ /*
+ * offset and length are unused for chain entry. Clear them.
+ */
+ prv[prv_nents - 1].offset = 0;
+ prv[prv_nents - 1].length = 0;
+
+ /*
+ * Set lowest bit to indicate a link pointer, and make sure to clear
+ * the termination bit if it happens to be set.
+ */
+ prv[prv_nents - 1].page_link = ((unsigned long) sgl | 0x01) & ~0x02;
}
+/**
+ * sg_mark_end - Mark the end of the scatterlist
+ * @sg: SG entryScatterlist
+ *
+ * Description:
+ * Marks the passed in sg entry as the termination point for the sg
+ * table. A call to sg_next() on this entry will return NULL.
+ *
+ **/
+static inline void sg_mark_end(struct scatterlist *sg)
+{
+#ifdef CONFIG_DEBUG_SG
+ BUG_ON(sg->sg_magic != SG_MAGIC);
+#endif
+ /*
+ * Set termination bit, clear potential chain bit
+ */
+ sg->page_link |= 0x02;
+ sg->page_link &= ~0x01;
+}
+
+/**
+ * sg_phys - Return physical address of an sg entry
+ * @sg: SG entry
+ *
+ * Description:
+ * This calls page_to_phys() on the page in this sg entry, and adds the
+ * sg offset. The caller must know that it is legal to call page_to_phys()
+ * on the sg page.
+ *
+ **/
+static inline dma_addr_t sg_phys(struct scatterlist *sg)
+{
+ return page_to_phys(sg_page(sg)) + sg->offset;
+}
+
+/**
+ * sg_virt - Return virtual address of an sg entry
+ * @sg: SG entry
+ *
+ * Description:
+ * This calls page_address() on the page in this sg entry, and adds the
+ * sg offset. The caller must know that the sg page has a valid virtual
+ * mapping.
+ *
+ **/
+static inline void *sg_virt(struct scatterlist *sg)
+{
+ return page_address(sg_page(sg)) + sg->offset;
+}
+
+struct scatterlist *sg_next(struct scatterlist *);
+struct scatterlist *sg_last(struct scatterlist *s, unsigned int);
+void sg_init_table(struct scatterlist *, unsigned int);
+void sg_init_one(struct scatterlist *, const void *, unsigned int);
+
+typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t);
+typedef void (sg_free_fn)(struct scatterlist *, unsigned int);
+
+void __sg_free_table(struct sg_table *, unsigned int, sg_free_fn *);
+void sg_free_table(struct sg_table *);
+int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, gfp_t,
+ sg_alloc_fn *);
+int sg_alloc_table(struct sg_table *, unsigned int, gfp_t);
+
+size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,
+ void *buf, size_t buflen);
+size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents,
+ void *buf, size_t buflen);
+
+/*
+ * Maximum number of entries that will be allocated in one piece, if
+ * a list larger than this is required then chaining will be utilized.
+ */
+#define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist))
+
+
+/*
+ * Mapping sg iterator
+ *
+ * Iterates over sg entries mapping page-by-page. On each successful
+ * iteration, @miter->page points to the mapped page and
+ * @miter->length bytes of data can be accessed at @miter->addr. As
+ * long as an interation is enclosed between start and stop, the user
+ * is free to choose control structure and when to stop.
+ *
+ * @miter->consumed is set to @miter->length on each iteration. It
+ * can be adjusted if the user can't consume all the bytes in one go.
+ * Also, a stopped iteration can be resumed by calling next on it.
+ * This is useful when iteration needs to release all resources and
+ * continue later (e.g. at the next interrupt).
+ */
+
+#define SG_MITER_ATOMIC (1 << 0) /* use kmap_atomic */
+#define SG_MITER_TO_SG (1 << 1) /* flush back to phys on unmap */
+#define SG_MITER_FROM_SG (1 << 2) /* nop */
+
+struct sg_mapping_iter {
+ /* the following three fields can be accessed directly */
+ struct page *page; /* currently mapped page */
+ void *addr; /* pointer to the mapped area */
+ size_t length; /* length of the mapped area */
+ size_t consumed; /* number of consumed bytes */
+
+ /* these are internal states, keep away */
+ struct scatterlist *__sg; /* current entry */
+ unsigned int __nents; /* nr of remaining entries */
+ unsigned int __offset; /* offset within sg */
+ unsigned int __flags;
+};
+
+void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl,
+ unsigned int nents, unsigned int flags);
+bool sg_miter_next(struct sg_mapping_iter *miter);
+void sg_miter_stop(struct sg_mapping_iter *miter);
+
#endif /* _LINUX_SCATTERLIST_H */
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff