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290 lines
6.2 KiB
290 lines
6.2 KiB
/*
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* DMA region bookkeeping routines
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*
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* Copyright (C) 2002 Maas Digital LLC
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*
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* This code is licensed under the GPL. See the file COPYING in the root
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* directory of the kernel sources for details.
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*/
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/pci.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/scatterlist.h>
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#include "dma.h"
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/* dma_prog_region */
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void dma_prog_region_init(struct dma_prog_region *prog)
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{
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prog->kvirt = NULL;
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prog->dev = NULL;
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prog->n_pages = 0;
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prog->bus_addr = 0;
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}
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int dma_prog_region_alloc(struct dma_prog_region *prog, unsigned long n_bytes,
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struct pci_dev *dev)
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{
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/* round up to page size */
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n_bytes = PAGE_ALIGN(n_bytes);
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prog->n_pages = n_bytes >> PAGE_SHIFT;
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prog->kvirt = pci_alloc_consistent(dev, n_bytes, &prog->bus_addr);
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if (!prog->kvirt) {
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printk(KERN_ERR
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"dma_prog_region_alloc: pci_alloc_consistent() failed\n");
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dma_prog_region_free(prog);
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return -ENOMEM;
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}
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prog->dev = dev;
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return 0;
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}
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void dma_prog_region_free(struct dma_prog_region *prog)
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{
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if (prog->kvirt) {
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pci_free_consistent(prog->dev, prog->n_pages << PAGE_SHIFT,
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prog->kvirt, prog->bus_addr);
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}
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prog->kvirt = NULL;
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prog->dev = NULL;
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prog->n_pages = 0;
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prog->bus_addr = 0;
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}
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/* dma_region */
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/**
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* dma_region_init - clear out all fields but do not allocate anything
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*/
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void dma_region_init(struct dma_region *dma)
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{
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dma->kvirt = NULL;
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dma->dev = NULL;
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dma->n_pages = 0;
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dma->n_dma_pages = 0;
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dma->sglist = NULL;
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}
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/**
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* dma_region_alloc - allocate the buffer and map it to the IOMMU
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*/
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int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes,
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struct pci_dev *dev, int direction)
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{
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unsigned int i;
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/* round up to page size */
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n_bytes = PAGE_ALIGN(n_bytes);
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dma->n_pages = n_bytes >> PAGE_SHIFT;
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dma->kvirt = vmalloc_32(n_bytes);
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if (!dma->kvirt) {
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printk(KERN_ERR "dma_region_alloc: vmalloc_32() failed\n");
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goto err;
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}
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/* Clear the ram out, no junk to the user */
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memset(dma->kvirt, 0, n_bytes);
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/* allocate scatter/gather list */
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dma->sglist = vmalloc(dma->n_pages * sizeof(*dma->sglist));
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if (!dma->sglist) {
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printk(KERN_ERR "dma_region_alloc: vmalloc(sglist) failed\n");
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goto err;
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}
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sg_init_table(dma->sglist, dma->n_pages);
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/* fill scatter/gather list with pages */
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for (i = 0; i < dma->n_pages; i++) {
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unsigned long va =
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(unsigned long)dma->kvirt + (i << PAGE_SHIFT);
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sg_set_page(&dma->sglist[i], vmalloc_to_page((void *)va),
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PAGE_SIZE, 0);
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}
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/* map sglist to the IOMMU */
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dma->n_dma_pages =
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pci_map_sg(dev, dma->sglist, dma->n_pages, direction);
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if (dma->n_dma_pages == 0) {
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printk(KERN_ERR "dma_region_alloc: pci_map_sg() failed\n");
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goto err;
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}
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dma->dev = dev;
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dma->direction = direction;
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return 0;
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err:
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dma_region_free(dma);
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return -ENOMEM;
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}
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/**
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* dma_region_free - unmap and free the buffer
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*/
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void dma_region_free(struct dma_region *dma)
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{
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if (dma->n_dma_pages) {
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pci_unmap_sg(dma->dev, dma->sglist, dma->n_pages,
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dma->direction);
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dma->n_dma_pages = 0;
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dma->dev = NULL;
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}
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vfree(dma->sglist);
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dma->sglist = NULL;
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vfree(dma->kvirt);
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dma->kvirt = NULL;
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dma->n_pages = 0;
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}
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/* find the scatterlist index and remaining offset corresponding to a
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given offset from the beginning of the buffer */
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static inline int dma_region_find(struct dma_region *dma, unsigned long offset,
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unsigned int start, unsigned long *rem)
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{
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int i;
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unsigned long off = offset;
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for (i = start; i < dma->n_dma_pages; i++) {
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if (off < sg_dma_len(&dma->sglist[i])) {
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*rem = off;
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break;
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}
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off -= sg_dma_len(&dma->sglist[i]);
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}
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BUG_ON(i >= dma->n_dma_pages);
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return i;
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}
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/**
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* dma_region_offset_to_bus - get bus address of an offset within a DMA region
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*
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* Returns the DMA bus address of the byte with the given @offset relative to
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* the beginning of the @dma.
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*/
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dma_addr_t dma_region_offset_to_bus(struct dma_region * dma,
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unsigned long offset)
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{
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unsigned long rem = 0;
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struct scatterlist *sg =
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&dma->sglist[dma_region_find(dma, offset, 0, &rem)];
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return sg_dma_address(sg) + rem;
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}
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/**
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* dma_region_sync_for_cpu - sync the CPU's view of the buffer
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*/
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void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset,
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unsigned long len)
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{
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int first, last;
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unsigned long rem = 0;
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if (!len)
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len = 1;
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first = dma_region_find(dma, offset, 0, &rem);
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last = dma_region_find(dma, rem + len - 1, first, &rem);
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pci_dma_sync_sg_for_cpu(dma->dev, &dma->sglist[first], last - first + 1,
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dma->direction);
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}
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/**
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* dma_region_sync_for_device - sync the IO bus' view of the buffer
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*/
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void dma_region_sync_for_device(struct dma_region *dma, unsigned long offset,
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unsigned long len)
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{
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int first, last;
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unsigned long rem = 0;
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if (!len)
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len = 1;
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first = dma_region_find(dma, offset, 0, &rem);
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last = dma_region_find(dma, rem + len - 1, first, &rem);
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pci_dma_sync_sg_for_device(dma->dev, &dma->sglist[first],
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last - first + 1, dma->direction);
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}
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#ifdef CONFIG_MMU
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static int dma_region_pagefault(struct vm_area_struct *vma,
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struct vm_fault *vmf)
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{
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struct dma_region *dma = (struct dma_region *)vma->vm_private_data;
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if (!dma->kvirt)
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return VM_FAULT_SIGBUS;
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if (vmf->pgoff >= dma->n_pages)
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return VM_FAULT_SIGBUS;
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vmf->page = vmalloc_to_page(dma->kvirt + (vmf->pgoff << PAGE_SHIFT));
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get_page(vmf->page);
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return 0;
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}
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static const struct vm_operations_struct dma_region_vm_ops = {
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.fault = dma_region_pagefault,
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};
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/**
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* dma_region_mmap - map the buffer into a user space process
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*/
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int dma_region_mmap(struct dma_region *dma, struct file *file,
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struct vm_area_struct *vma)
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{
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unsigned long size;
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if (!dma->kvirt)
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return -EINVAL;
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/* must be page-aligned (XXX: comment is wrong, we could allow pgoff) */
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if (vma->vm_pgoff != 0)
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return -EINVAL;
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/* check the length */
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size = vma->vm_end - vma->vm_start;
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if (size > (dma->n_pages << PAGE_SHIFT))
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return -EINVAL;
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vma->vm_ops = &dma_region_vm_ops;
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vma->vm_private_data = dma;
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vma->vm_file = file;
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vma->vm_flags |= VM_RESERVED | VM_ALWAYSDUMP;
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return 0;
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}
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#else /* CONFIG_MMU */
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int dma_region_mmap(struct dma_region *dma, struct file *file,
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struct vm_area_struct *vma)
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{
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return -EINVAL;
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}
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#endif /* CONFIG_MMU */
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