/* * 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 */