/* * helper functions for physically contiguous capture buffers * * The functions support hardware lacking scatter gather support * (i.e. the buffers must be linear in physical memory) * * Copyright (c) 2008 Magnus Damm * * Based on videobuf-vmalloc.c, * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 */ #include <linux/init.h> #include <linux/module.h> #include <linux/mm.h> #include <linux/dma-mapping.h> #include <media/videobuf-dma-contig.h> struct videobuf_dma_contig_memory { u32 magic; void *vaddr; dma_addr_t dma_handle; unsigned long size; }; #define MAGIC_DC_MEM 0x0733ac61 #define MAGIC_CHECK(is, should) \ if (unlikely((is) != (should))) { \ pr_err("magic mismatch: %x expected %x\n", (is), (should)); \ BUG(); \ } static void videobuf_vm_open(struct vm_area_struct *vma) { struct videobuf_mapping *map = vma->vm_private_data; dev_dbg(map->q->dev, "vm_open %p [count=%u,vma=%08lx-%08lx]\n", map, map->count, vma->vm_start, vma->vm_end); map->count++; } static void videobuf_vm_close(struct vm_area_struct *vma) { struct videobuf_mapping *map = vma->vm_private_data; struct videobuf_queue *q = map->q; int i; dev_dbg(map->q->dev, "vm_close %p [count=%u,vma=%08lx-%08lx]\n", map, map->count, vma->vm_start, vma->vm_end); map->count--; if (0 == map->count) { struct videobuf_dma_contig_memory *mem; dev_dbg(map->q->dev, "munmap %p q=%p\n", map, q); mutex_lock(&q->vb_lock); /* We need first to cancel streams, before unmapping */ if (q->streaming) videobuf_queue_cancel(q); for (i = 0; i < VIDEO_MAX_FRAME; i++) { if (NULL == q->bufs[i]) continue; if (q->bufs[i]->map != map) continue; mem = q->bufs[i]->priv; if (mem) { /* This callback is called only if kernel has allocated memory and this memory is mmapped. In this case, memory should be freed, in order to do memory unmap. */ MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); /* vfree is not atomic - can't be called with IRQ's disabled */ dev_dbg(map->q->dev, "buf[%d] freeing %p\n", i, mem->vaddr); dma_free_coherent(q->dev, mem->size, mem->vaddr, mem->dma_handle); mem->vaddr = NULL; } q->bufs[i]->map = NULL; q->bufs[i]->baddr = 0; } kfree(map); mutex_unlock(&q->vb_lock); } } static struct vm_operations_struct videobuf_vm_ops = { .open = videobuf_vm_open, .close = videobuf_vm_close, }; static void *__videobuf_alloc(size_t size) { struct videobuf_dma_contig_memory *mem; struct videobuf_buffer *vb; vb = kzalloc(size + sizeof(*mem), GFP_KERNEL); if (vb) { mem = vb->priv = ((char *)vb) + size; mem->magic = MAGIC_DC_MEM; } return vb; } static void *__videobuf_to_vmalloc(struct videobuf_buffer *buf) { struct videobuf_dma_contig_memory *mem = buf->priv; BUG_ON(!mem); MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); return mem->vaddr; } static int __videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb, struct v4l2_framebuffer *fbuf) { struct videobuf_dma_contig_memory *mem = vb->priv; BUG_ON(!mem); MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); switch (vb->memory) { case V4L2_MEMORY_MMAP: dev_dbg(q->dev, "%s memory method MMAP\n", __func__); /* All handling should be done by __videobuf_mmap_mapper() */ if (!mem->vaddr) { dev_err(q->dev, "memory is not alloced/mmapped.\n"); return -EINVAL; } break; case V4L2_MEMORY_USERPTR: dev_dbg(q->dev, "%s memory method USERPTR\n", __func__); /* The only USERPTR currently supported is the one needed for read() method. */ if (vb->baddr) return -EINVAL; mem->size = PAGE_ALIGN(vb->size); mem->vaddr = dma_alloc_coherent(q->dev, mem->size, &mem->dma_handle, GFP_KERNEL); if (!mem->vaddr) { dev_err(q->dev, "dma_alloc_coherent %ld failed\n", mem->size); return -ENOMEM; } dev_dbg(q->dev, "dma_alloc_coherent data is at %p (%ld)\n", mem->vaddr, mem->size); break; case V4L2_MEMORY_OVERLAY: default: dev_dbg(q->dev, "%s memory method OVERLAY/unknown\n", __func__); return -EINVAL; } return 0; } static int __videobuf_sync(struct videobuf_queue *q, struct videobuf_buffer *buf) { struct videobuf_dma_contig_memory *mem = buf->priv; BUG_ON(!mem); MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); dma_sync_single_for_cpu(q->dev, mem->dma_handle, mem->size, DMA_FROM_DEVICE); return 0; } static int __videobuf_mmap_free(struct videobuf_queue *q) { unsigned int i; dev_dbg(q->dev, "%s\n", __func__); for (i = 0; i < VIDEO_MAX_FRAME; i++) { if (q->bufs[i] && q->bufs[i]->map) return -EBUSY; } return 0; } static int __videobuf_mmap_mapper(struct videobuf_queue *q, struct vm_area_struct *vma) { struct videobuf_dma_contig_memory *mem; struct videobuf_mapping *map; unsigned int first; int retval; unsigned long size, offset = vma->vm_pgoff << PAGE_SHIFT; dev_dbg(q->dev, "%s\n", __func__); if (!(vma->vm_flags & VM_WRITE) || !(vma->vm_flags & VM_SHARED)) return -EINVAL; /* look for first buffer to map */ for (first = 0; first < VIDEO_MAX_FRAME; first++) { if (!q->bufs[first]) continue; if (V4L2_MEMORY_MMAP != q->bufs[first]->memory) continue; if (q->bufs[first]->boff == offset) break; } if (VIDEO_MAX_FRAME == first) { dev_dbg(q->dev, "invalid user space offset [offset=0x%lx]\n", offset); return -EINVAL; } /* create mapping + update buffer list */ map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL); if (!map) return -ENOMEM; q->bufs[first]->map = map; map->start = vma->vm_start; map->end = vma->vm_end; map->q = q; q->bufs[first]->baddr = vma->vm_start; mem = q->bufs[first]->priv; BUG_ON(!mem); MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); mem->size = PAGE_ALIGN(q->bufs[first]->bsize); mem->vaddr = dma_alloc_coherent(q->dev, mem->size, &mem->dma_handle, GFP_KERNEL); if (!mem->vaddr) { dev_err(q->dev, "dma_alloc_coherent size %ld failed\n", mem->size); goto error; } dev_dbg(q->dev, "dma_alloc_coherent data is at addr %p (size %ld)\n", mem->vaddr, mem->size); /* Try to remap memory */ size = vma->vm_end - vma->vm_start; size = (size < mem->size) ? size : mem->size; vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); retval = remap_pfn_range(vma, vma->vm_start, mem->dma_handle >> PAGE_SHIFT, size, vma->vm_page_prot); if (retval) { dev_err(q->dev, "mmap: remap failed with error %d. ", retval); dma_free_coherent(q->dev, mem->size, mem->vaddr, mem->dma_handle); goto error; } vma->vm_ops = &videobuf_vm_ops; vma->vm_flags |= VM_DONTEXPAND; vma->vm_private_data = map; dev_dbg(q->dev, "mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n", map, q, vma->vm_start, vma->vm_end, (long int) q->bufs[first]->bsize, vma->vm_pgoff, first); videobuf_vm_open(vma); return 0; error: kfree(map); return -ENOMEM; } static int __videobuf_copy_to_user(struct videobuf_queue *q, char __user *data, size_t count, int nonblocking) { struct videobuf_dma_contig_memory *mem = q->read_buf->priv; void *vaddr; BUG_ON(!mem); MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); BUG_ON(!mem->vaddr); /* copy to userspace */ if (count > q->read_buf->size - q->read_off) count = q->read_buf->size - q->read_off; vaddr = mem->vaddr; if (copy_to_user(data, vaddr + q->read_off, count)) return -EFAULT; return count; } static int __videobuf_copy_stream(struct videobuf_queue *q, char __user *data, size_t count, size_t pos, int vbihack, int nonblocking) { unsigned int *fc; struct videobuf_dma_contig_memory *mem = q->read_buf->priv; BUG_ON(!mem); MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); if (vbihack) { /* dirty, undocumented hack -- pass the frame counter * within the last four bytes of each vbi data block. * We need that one to maintain backward compatibility * to all vbi decoding software out there ... */ fc = (unsigned int *)mem->vaddr; fc += (q->read_buf->size >> 2) - 1; *fc = q->read_buf->field_count >> 1; dev_dbg(q->dev, "vbihack: %d\n", *fc); } /* copy stuff using the common method */ count = __videobuf_copy_to_user(q, data, count, nonblocking); if ((count == -EFAULT) && (pos == 0)) return -EFAULT; return count; } static struct videobuf_qtype_ops qops = { .magic = MAGIC_QTYPE_OPS, .alloc = __videobuf_alloc, .iolock = __videobuf_iolock, .sync = __videobuf_sync, .mmap_free = __videobuf_mmap_free, .mmap_mapper = __videobuf_mmap_mapper, .video_copy_to_user = __videobuf_copy_to_user, .copy_stream = __videobuf_copy_stream, .vmalloc = __videobuf_to_vmalloc, }; void videobuf_queue_dma_contig_init(struct videobuf_queue *q, struct videobuf_queue_ops *ops, struct device *dev, spinlock_t *irqlock, enum v4l2_buf_type type, enum v4l2_field field, unsigned int msize, void *priv) { videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize, priv, &qops); } EXPORT_SYMBOL_GPL(videobuf_queue_dma_contig_init); dma_addr_t videobuf_to_dma_contig(struct videobuf_buffer *buf) { struct videobuf_dma_contig_memory *mem = buf->priv; BUG_ON(!mem); MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); return mem->dma_handle; } EXPORT_SYMBOL_GPL(videobuf_to_dma_contig); void videobuf_dma_contig_free(struct videobuf_queue *q, struct videobuf_buffer *buf) { struct videobuf_dma_contig_memory *mem = buf->priv; /* mmapped memory can't be freed here, otherwise mmapped region would be released, while still needed. In this case, the memory release should happen inside videobuf_vm_close(). So, it should free memory only if the memory were allocated for read() operation. */ if ((buf->memory != V4L2_MEMORY_USERPTR) || !buf->baddr) return; if (!mem) return; MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); dma_free_coherent(q->dev, mem->size, mem->vaddr, mem->dma_handle); mem->vaddr = NULL; } EXPORT_SYMBOL_GPL(videobuf_dma_contig_free); MODULE_DESCRIPTION("helper module to manage video4linux dma contig buffers"); MODULE_AUTHOR("Magnus Damm"); MODULE_LICENSE("GPL");