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e275faf367
This patch is a part of a series that extends kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments. videobuf_dma_contig_user_get() uses provided user pointers for vma lookups, which can only by done with untagged pointers. Untag the pointers in this function. Link: http://lkml.kernel.org/r/100436d5f8e4349a78f27b0bbb27e4801fcb946b.1563904656.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Eric Auger <eric.auger@redhat.com> Cc: Felix Kuehling <Felix.Kuehling@amd.com> Cc: Jens Wiklander <jens.wiklander@linaro.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
409 lines
9.6 KiB
C
409 lines
9.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* helper functions for physically contiguous capture buffers
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*
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* The functions support hardware lacking scatter gather support
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* (i.e. the buffers must be linear in physical memory)
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*
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* Copyright (c) 2008 Magnus Damm
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*
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* Based on videobuf-vmalloc.c,
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* (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.org>
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/pagemap.h>
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#include <linux/dma-mapping.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <media/videobuf-dma-contig.h>
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struct videobuf_dma_contig_memory {
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u32 magic;
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void *vaddr;
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dma_addr_t dma_handle;
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unsigned long size;
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};
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#define MAGIC_DC_MEM 0x0733ac61
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#define MAGIC_CHECK(is, should) \
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if (unlikely((is) != (should))) { \
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pr_err("magic mismatch: %x expected %x\n", (is), (should)); \
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BUG(); \
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}
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static int __videobuf_dc_alloc(struct device *dev,
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struct videobuf_dma_contig_memory *mem,
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unsigned long size, gfp_t flags)
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{
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mem->size = size;
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mem->vaddr = dma_alloc_coherent(dev, mem->size,
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&mem->dma_handle, flags);
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if (!mem->vaddr) {
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dev_err(dev, "memory alloc size %ld failed\n", mem->size);
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return -ENOMEM;
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}
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dev_dbg(dev, "dma mapped data is at %p (%ld)\n", mem->vaddr, mem->size);
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return 0;
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}
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static void __videobuf_dc_free(struct device *dev,
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struct videobuf_dma_contig_memory *mem)
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{
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dma_free_coherent(dev, mem->size, mem->vaddr, mem->dma_handle);
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mem->vaddr = NULL;
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}
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static void videobuf_vm_open(struct vm_area_struct *vma)
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{
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struct videobuf_mapping *map = vma->vm_private_data;
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dev_dbg(map->q->dev, "vm_open %p [count=%u,vma=%08lx-%08lx]\n",
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map, map->count, vma->vm_start, vma->vm_end);
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map->count++;
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}
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static void videobuf_vm_close(struct vm_area_struct *vma)
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{
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struct videobuf_mapping *map = vma->vm_private_data;
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struct videobuf_queue *q = map->q;
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int i;
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dev_dbg(q->dev, "vm_close %p [count=%u,vma=%08lx-%08lx]\n",
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map, map->count, vma->vm_start, vma->vm_end);
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map->count--;
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if (0 == map->count) {
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struct videobuf_dma_contig_memory *mem;
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dev_dbg(q->dev, "munmap %p q=%p\n", map, q);
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videobuf_queue_lock(q);
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/* We need first to cancel streams, before unmapping */
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if (q->streaming)
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videobuf_queue_cancel(q);
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for (i = 0; i < VIDEO_MAX_FRAME; i++) {
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if (NULL == q->bufs[i])
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continue;
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if (q->bufs[i]->map != map)
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continue;
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mem = q->bufs[i]->priv;
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if (mem) {
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/* This callback is called only if kernel has
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allocated memory and this memory is mmapped.
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In this case, memory should be freed,
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in order to do memory unmap.
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*/
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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/* vfree is not atomic - can't be
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called with IRQ's disabled
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*/
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dev_dbg(q->dev, "buf[%d] freeing %p\n",
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i, mem->vaddr);
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__videobuf_dc_free(q->dev, mem);
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mem->vaddr = NULL;
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}
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q->bufs[i]->map = NULL;
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q->bufs[i]->baddr = 0;
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}
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kfree(map);
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videobuf_queue_unlock(q);
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}
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}
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static const struct vm_operations_struct videobuf_vm_ops = {
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.open = videobuf_vm_open,
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.close = videobuf_vm_close,
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};
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/**
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* videobuf_dma_contig_user_put() - reset pointer to user space buffer
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* @mem: per-buffer private videobuf-dma-contig data
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*
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* This function resets the user space pointer
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*/
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static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem)
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{
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mem->dma_handle = 0;
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mem->size = 0;
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}
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/**
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* videobuf_dma_contig_user_get() - setup user space memory pointer
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* @mem: per-buffer private videobuf-dma-contig data
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* @vb: video buffer to map
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*
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* This function validates and sets up a pointer to user space memory.
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* Only physically contiguous pfn-mapped memory is accepted.
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*
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* Returns 0 if successful.
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*/
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static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
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struct videobuf_buffer *vb)
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{
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unsigned long untagged_baddr = untagged_addr(vb->baddr);
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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unsigned long prev_pfn, this_pfn;
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unsigned long pages_done, user_address;
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unsigned int offset;
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int ret;
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offset = untagged_baddr & ~PAGE_MASK;
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mem->size = PAGE_ALIGN(vb->size + offset);
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ret = -EINVAL;
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down_read(&mm->mmap_sem);
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vma = find_vma(mm, untagged_baddr);
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if (!vma)
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goto out_up;
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if ((untagged_baddr + mem->size) > vma->vm_end)
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goto out_up;
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pages_done = 0;
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prev_pfn = 0; /* kill warning */
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user_address = untagged_baddr;
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while (pages_done < (mem->size >> PAGE_SHIFT)) {
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ret = follow_pfn(vma, user_address, &this_pfn);
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if (ret)
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break;
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if (pages_done == 0)
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mem->dma_handle = (this_pfn << PAGE_SHIFT) + offset;
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else if (this_pfn != (prev_pfn + 1))
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ret = -EFAULT;
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if (ret)
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break;
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prev_pfn = this_pfn;
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user_address += PAGE_SIZE;
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pages_done++;
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}
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out_up:
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up_read(¤t->mm->mmap_sem);
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return ret;
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}
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static struct videobuf_buffer *__videobuf_alloc(size_t size)
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{
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struct videobuf_dma_contig_memory *mem;
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struct videobuf_buffer *vb;
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vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
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if (vb) {
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vb->priv = ((char *)vb) + size;
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mem = vb->priv;
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mem->magic = MAGIC_DC_MEM;
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}
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return vb;
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}
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static void *__videobuf_to_vaddr(struct videobuf_buffer *buf)
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{
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struct videobuf_dma_contig_memory *mem = buf->priv;
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BUG_ON(!mem);
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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return mem->vaddr;
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}
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static int __videobuf_iolock(struct videobuf_queue *q,
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struct videobuf_buffer *vb,
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struct v4l2_framebuffer *fbuf)
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{
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struct videobuf_dma_contig_memory *mem = vb->priv;
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BUG_ON(!mem);
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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switch (vb->memory) {
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case V4L2_MEMORY_MMAP:
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dev_dbg(q->dev, "%s memory method MMAP\n", __func__);
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/* All handling should be done by __videobuf_mmap_mapper() */
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if (!mem->vaddr) {
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dev_err(q->dev, "memory is not allocated/mmapped.\n");
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return -EINVAL;
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}
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break;
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case V4L2_MEMORY_USERPTR:
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dev_dbg(q->dev, "%s memory method USERPTR\n", __func__);
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/* handle pointer from user space */
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if (vb->baddr)
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return videobuf_dma_contig_user_get(mem, vb);
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/* allocate memory for the read() method */
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if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(vb->size),
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GFP_KERNEL))
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return -ENOMEM;
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break;
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case V4L2_MEMORY_OVERLAY:
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default:
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dev_dbg(q->dev, "%s memory method OVERLAY/unknown\n", __func__);
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return -EINVAL;
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}
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return 0;
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}
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static int __videobuf_mmap_mapper(struct videobuf_queue *q,
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struct videobuf_buffer *buf,
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struct vm_area_struct *vma)
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{
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struct videobuf_dma_contig_memory *mem;
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struct videobuf_mapping *map;
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int retval;
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dev_dbg(q->dev, "%s\n", __func__);
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/* create mapping + update buffer list */
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map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
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if (!map)
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return -ENOMEM;
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buf->map = map;
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map->q = q;
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buf->baddr = vma->vm_start;
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mem = buf->priv;
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BUG_ON(!mem);
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(buf->bsize),
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GFP_KERNEL | __GFP_COMP))
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goto error;
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/* Try to remap memory */
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vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
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/* the "vm_pgoff" is just used in v4l2 to find the
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* corresponding buffer data structure which is allocated
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* earlier and it does not mean the offset from the physical
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* buffer start address as usual. So set it to 0 to pass
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* the sanity check in vm_iomap_memory().
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*/
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vma->vm_pgoff = 0;
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retval = vm_iomap_memory(vma, mem->dma_handle, mem->size);
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if (retval) {
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dev_err(q->dev, "mmap: remap failed with error %d. ",
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retval);
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dma_free_coherent(q->dev, mem->size,
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mem->vaddr, mem->dma_handle);
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goto error;
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}
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vma->vm_ops = &videobuf_vm_ops;
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vma->vm_flags |= VM_DONTEXPAND;
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vma->vm_private_data = map;
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dev_dbg(q->dev, "mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
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map, q, vma->vm_start, vma->vm_end,
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(long int)buf->bsize, vma->vm_pgoff, buf->i);
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videobuf_vm_open(vma);
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return 0;
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error:
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kfree(map);
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return -ENOMEM;
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}
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static struct videobuf_qtype_ops qops = {
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.magic = MAGIC_QTYPE_OPS,
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.alloc_vb = __videobuf_alloc,
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.iolock = __videobuf_iolock,
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.mmap_mapper = __videobuf_mmap_mapper,
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.vaddr = __videobuf_to_vaddr,
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};
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void videobuf_queue_dma_contig_init(struct videobuf_queue *q,
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const struct videobuf_queue_ops *ops,
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struct device *dev,
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spinlock_t *irqlock,
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enum v4l2_buf_type type,
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enum v4l2_field field,
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unsigned int msize,
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void *priv,
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struct mutex *ext_lock)
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{
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videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
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priv, &qops, ext_lock);
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}
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EXPORT_SYMBOL_GPL(videobuf_queue_dma_contig_init);
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dma_addr_t videobuf_to_dma_contig(struct videobuf_buffer *buf)
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{
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struct videobuf_dma_contig_memory *mem = buf->priv;
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BUG_ON(!mem);
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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return mem->dma_handle;
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}
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EXPORT_SYMBOL_GPL(videobuf_to_dma_contig);
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void videobuf_dma_contig_free(struct videobuf_queue *q,
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struct videobuf_buffer *buf)
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{
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struct videobuf_dma_contig_memory *mem = buf->priv;
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/* mmapped memory can't be freed here, otherwise mmapped region
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would be released, while still needed. In this case, the memory
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release should happen inside videobuf_vm_close().
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So, it should free memory only if the memory were allocated for
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read() operation.
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*/
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if (buf->memory != V4L2_MEMORY_USERPTR)
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return;
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if (!mem)
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return;
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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/* handle user space pointer case */
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if (buf->baddr) {
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videobuf_dma_contig_user_put(mem);
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return;
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}
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/* read() method */
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if (mem->vaddr) {
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__videobuf_dc_free(q->dev, mem);
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mem->vaddr = NULL;
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}
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}
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EXPORT_SYMBOL_GPL(videobuf_dma_contig_free);
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MODULE_DESCRIPTION("helper module to manage video4linux dma contig buffers");
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MODULE_AUTHOR("Magnus Damm");
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MODULE_LICENSE("GPL");
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