* 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 */
/* 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;
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)
{
return -ENOMEM;
}
+/**
+ * dma_region_free - unmap and free the buffer
+ */
void dma_region_free(struct dma_region *dma)
{
if (dma->n_dma_pages) {
/* 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;
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);
.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)
{