--- /dev/null
+/*
+ * 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/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");
projects / linux-2.6 / commitdiff