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408 lines
9.6 KiB
408 lines
9.6 KiB
// 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, <[email protected]> |
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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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mmap_read_lock(mm); |
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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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mmap_read_unlock(current->mm); |
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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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