X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fieee1394%2Fdma.c;h=45d6055819227367fb318e472b1ee2de990b458f;hb=ea9057ad622db41745be416e29c5760d141a6514;hp=9fb2769d9abca9b25f3e136a79a48609ff5ee0dc;hpb=9fdb62af92c741addbea15545f214a6e89460865;p=linux-2.6-omap-h63xx.git

diff --git a/drivers/ieee1394/dma.c b/drivers/ieee1394/dma.c
index 9fb2769d9ab..45d60558192 100644
--- a/drivers/ieee1394/dma.c
+++ b/drivers/ieee1394/dma.c
@@ -7,10 +7,13 @@
  * directory of the kernel sources for details.
  */
 
+#include <linux/mm.h>
 #include <linux/module.h>
-#include <linux/vmalloc.h>
+#include <linux/pci.h>
 #include <linux/slab.h>
-#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <asm/scatterlist.h>
+
 #include "dma.h"
 
 /* dma_prog_region */
@@ -59,6 +62,9 @@ void dma_prog_region_free(struct dma_prog_region *prog)
 
 /* dma_region */
 
+/**
+ * dma_region_init - clear out all fields but do not allocate anything
+ */
 void dma_region_init(struct dma_region *dma)
 {
 	dma->kvirt = NULL;
@@ -68,6 +74,9 @@ void dma_region_init(struct dma_region *dma)
 	dma->sglist = NULL;
 }
 
+/**
+ * dma_region_alloc - allocate the buffer and map it to the IOMMU
+ */
 int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes,
 		     struct pci_dev *dev, int direction)
 {
@@ -125,6 +134,9 @@ int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes,
 	return -ENOMEM;
 }
 
+/**
+ * dma_region_free - unmap and free the buffer
+ */
 void dma_region_free(struct dma_region *dma)
 {
 	if (dma->n_dma_pages) {
@@ -145,12 +157,12 @@ void dma_region_free(struct dma_region *dma)
 /* find the scatterlist index and remaining offset corresponding to a
    given offset from the beginning of the buffer */
 static inline int dma_region_find(struct dma_region *dma, unsigned long offset,
-				  unsigned long *rem)
+				  unsigned int start, unsigned long *rem)
 {
 	int i;
 	unsigned long off = offset;
 
-	for (i = 0; i < dma->n_dma_pages; i++) {
+	for (i = start; i < dma->n_dma_pages; i++) {
 		if (off < sg_dma_len(&dma->sglist[i])) {
 			*rem = off;
 			break;
@@ -164,43 +176,55 @@ static inline int dma_region_find(struct dma_region *dma, unsigned long offset,
 	return i;
 }
 
+/**
+ * dma_region_offset_to_bus - get bus address of an offset within a DMA region
+ *
+ * Returns the DMA bus address of the byte with the given @offset relative to
+ * the beginning of the @dma.
+ */
 dma_addr_t dma_region_offset_to_bus(struct dma_region * dma,
 				    unsigned long offset)
 {
 	unsigned long rem = 0;
 
 	struct scatterlist *sg =
-	    &dma->sglist[dma_region_find(dma, offset, &rem)];
+	    &dma->sglist[dma_region_find(dma, offset, 0, &rem)];
 	return sg_dma_address(sg) + rem;
 }
 
+/**
+ * dma_region_sync_for_cpu - sync the CPU's view of the buffer
+ */
 void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset,
 			     unsigned long len)
 {
 	int first, last;
-	unsigned long rem;
+	unsigned long rem = 0;
 
 	if (!len)
 		len = 1;
 
-	first = dma_region_find(dma, offset, &rem);
-	last = dma_region_find(dma, offset + len - 1, &rem);
+	first = dma_region_find(dma, offset, 0, &rem);
+	last = dma_region_find(dma, rem + len - 1, first, &rem);
 
 	pci_dma_sync_sg_for_cpu(dma->dev, &dma->sglist[first], last - first + 1,
 				dma->direction);
 }
 
+/**
+ * dma_region_sync_for_device - sync the IO bus' view of the buffer
+ */
 void dma_region_sync_for_device(struct dma_region *dma, unsigned long offset,
 				unsigned long len)
 {
 	int first, last;
-	unsigned long rem;
+	unsigned long rem = 0;
 
 	if (!len)
 		len = 1;
 
-	first = dma_region_find(dma, offset, &rem);
-	last = dma_region_find(dma, offset + len - 1, &rem);
+	first = dma_region_find(dma, offset, 0, &rem);
+	last = dma_region_find(dma, rem + len - 1, first, &rem);
 
 	pci_dma_sync_sg_for_device(dma->dev, &dma->sglist[first],
 				   last - first + 1, dma->direction);
@@ -241,6 +265,9 @@ static struct vm_operations_struct dma_region_vm_ops = {
 	.nopage = dma_region_pagefault,
 };
 
+/**
+ * dma_region_mmap - map the buffer into a user space process
+ */
 int dma_region_mmap(struct dma_region *dma, struct file *file,
 		    struct vm_area_struct *vma)
 {