1 /* 2 * Copyright © 2014 Intel Corporation 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 * 23 */ 24 25 #include <linux/mm.h> 26 #include <linux/io-mapping.h> 27 28 29 #include "i915_drv.h" 30 31 #define EXPECTED_FLAGS (VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP) 32 33 #define use_dma(io) ((io) != -1) 34 35 /** 36 * remap_io_sg - remap an IO mapping to userspace 37 * @vma: user vma to map to 38 * @addr: target user address to start at 39 * @size: size of map area 40 * @sgl: Start sg entry 41 * @iobase: Use stored dma address offset by this address or pfn if -1 42 * 43 * Note: this is only safe if the mm semaphore is held when called. 44 */ 45 int remap_io_sg(struct vm_area_struct *vma, 46 unsigned long addr, unsigned long size, 47 struct scatterlist *sgl, resource_size_t iobase) 48 { 49 unsigned long pfn, len, remapped = 0; 50 int err; 51 52 /* We rely on prevalidation of the io-mapping to skip track_pfn(). */ 53 GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS); 54 55 if (!use_dma(iobase)) 56 flush_cache_range(vma, addr, size); 57 58 do { 59 if (use_dma(iobase)) { 60 if (!sg_dma_len(sgl)) 61 break; 62 pfn = (sg_dma_address(sgl) + iobase) >> PAGE_SHIFT; 63 len = sg_dma_len(sgl); 64 } else { 65 pfn = page_to_pfn(sg_page(sgl)); 66 len = sgl->length; 67 } 68 69 err = remap_pfn_range(vma, addr + remapped, pfn, len, 70 vma->vm_page_prot); 71 if (err) 72 break; 73 remapped += len; 74 } while ((sgl = __sg_next(sgl))); 75 76 if (err) 77 zap_vma_ptes(vma, addr, remapped); 78 return err; 79 } 80