/*
* DMA region bookkeeping routines
*
* Copyright (C) 2002 Maas Digital LLC
*
* This code is licensed under the GPL. See the file COPYING in the root
* directory of the kernel sources for details.
*/
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <asm/scatterlist.h>
#include "dma.h"
/* dma_prog_region */
void dma_prog_region_init(struct dma_prog_region *prog)
{
prog->kvirt = NULL;
prog->dev = NULL;
prog->n_pages = 0;
prog->bus_addr = 0;
}
int dma_prog_region_alloc(struct dma_prog_region *prog, unsigned long n_bytes,
struct pci_dev *dev)
{
/* round up to page size */
n_bytes = PAGE_ALIGN(n_bytes);
prog->n_pages = n_bytes >> PAGE_SHIFT;
prog->kvirt = pci_alloc_consistent(dev, n_bytes, &prog->bus_addr);
if (!prog->kvirt) {
printk(KERN_ERR
"dma_prog_region_alloc: pci_alloc_consistent() failed\n");
dma_prog_region_free(prog);
return -ENOMEM;
}
prog->dev = dev;
return 0;
}
void dma_prog_region_free(struct dma_prog_region *prog)
{
if (prog->kvirt) {
pci_free_consistent(prog->dev, prog->n_pages << PAGE_SHIFT,
prog->kvirt, prog->bus_addr);
}
prog->kvirt = NULL;
prog->dev = NULL;
prog->n_pages = 0;
prog->bus_addr = 0;
}
/* 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->dev = NULL;
dma->n_pages = 0;
dma->n_dma_pages = 0;
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)
{
unsigned int i;
/* round up to page size */
n_bytes = PAGE_ALIGN(n_bytes);
dma->n_pages = n_bytes >> PAGE_SHIFT;
dma->kvirt = vmalloc_32(n_bytes);
if (!dma->kvirt) {
printk(KERN_ERR "dma_region_alloc: vmalloc_32() failed\n");
goto err;
}
/* Clear the ram out, no junk to the user */
memset(dma->kvirt, 0, n_bytes);
/* allocate scatter/gather list */
dma->sglist = vmalloc(dma->n_pages * sizeof(*dma->sglist));
if (!dma->sglist) {
printk(KERN_ERR "dma_region_alloc: vmalloc(sglist) failed\n");
goto err;
}
/* just to be safe - this will become unnecessary once sglist->address goes away */
memset(dma->sglist, 0, dma->n_pages * sizeof(*dma->sglist));
/* fill scatter/gather list with pages */
for (i = 0; i < dma->n_pages; i++) {
unsigned long va =
(unsigned long)dma->kvirt + (i << PAGE_SHIFT);
dma->sglist[i].page = vmalloc_to_page((void *)va);
dma->sglist[i].length = PAGE_SIZE;
}
/* map sglist to the IOMMU */
dma->n_dma_pages =
pci_map_sg(dev, dma->sglist, dma->n_pages, direction);
if (dma->n_dma_pages == 0) {
printk(KERN_ERR "dma_region_alloc: pci_map_sg() failed\n");
goto err;
}
dma->dev = dev;
dma->direction = direction;
return 0;
err:
dma_region_free(dma);
return -ENOMEM;
}
/**
* dma_region_free - unmap and free the buffer
*/
void dma_region_free(struct dma_region *dma)
{
if (dma->n_dma_pages) {
pci_unmap_sg(dma->dev, dma->sglist, dma->n_pages,
dma->direction);
dma->n_dma_pages = 0;
dma->dev = NULL;
}
vfree(dma->sglist);
dma->sglist = NULL;
vfree(dma->kvirt);
dma->kvirt = NULL;
dma->n_pages = 0;
}
/* 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 int start, unsigned long *rem)
{
int i;
unsigned long off = offset;
for (i = start; i < dma->n_dma_pages; i++) {
if (off < sg_dma_len(&dma->sglist[i])) {
*rem = off;
break;
}
off -= sg_dma_len(&dma->sglist[i]);
}
BUG_ON(i >= dma->n_dma_pages);
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, 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 = 0;
if (!len)
len = 1;
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 = 0;
if (!len)
len = 1;
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);
}
#ifdef CONFIG_MMU
/* nopage() handler for mmap access */
static struct page *dma_region_pagefault(struct vm_area_struct *area,
unsigned long address, int *type)
{
unsigned long offset;
unsigned long kernel_virt_addr;
struct page *ret = NOPAGE_SIGBUS;
struct dma_region *dma = (struct dma_region *)area->vm_private_data;
if (!dma->kvirt)
goto out;
if ((address < (unsigned long)area->vm_start) ||
(address >
(unsigned long)area->vm_start + (dma->n_pages << PAGE_SHIFT)))
goto out;
if (type)
*type = VM_FAULT_MINOR;
offset = address - area->vm_start;
kernel_virt_addr = (unsigned long)dma->kvirt + offset;
ret = vmalloc_to_page((void *)kernel_virt_addr);
get_page(ret);
out:
return ret;
}
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)
{
unsigned long size;
if (!dma->kvirt)
return -EINVAL;
/* must be page-aligned */
if (vma->vm_pgoff != 0)
return -EINVAL;
/* check the length */
size = vma->vm_end - vma->vm_start;
if (size > (dma->n_pages << PAGE_SHIFT))
return -EINVAL;
vma->vm_ops = &dma_region_vm_ops;
vma->vm_private_data = dma;
vma->vm_file = file;
vma->vm_flags |= VM_RESERVED;
return 0;
}
#else /* CONFIG_MMU */
int dma_region_mmap(struct dma_region *dma, struct file *file,
struct vm_area_struct *vma)
{
return -EINVAL;
}
#endif /* CONFIG_MMU */
