--- /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/mm.h>
+#include <linux/pagemap.h>
+#include <linux/dma-mapping.h>
+#include <linux/sched.h>
+#include <linux/slab.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 int __videobuf_dc_alloc(struct device *dev,
+ struct videobuf_dma_contig_memory *mem,
+ unsigned long size, gfp_t flags)
+{
+ mem->size = size;
+ mem->vaddr = dma_alloc_coherent(dev, mem->size,
+ &mem->dma_handle, flags);
+
+ if (!mem->vaddr) {
+ dev_err(dev, "memory alloc size %ld failed\n", mem->size);
+ return -ENOMEM;
+ }
+
+ dev_dbg(dev, "dma mapped data is at %p (%ld)\n", mem->vaddr, mem->size);
+
+ return 0;
+}
+
+static void __videobuf_dc_free(struct device *dev,
+ struct videobuf_dma_contig_memory *mem)
+{
+ dma_free_coherent(dev, mem->size, mem->vaddr, mem->dma_handle);
+
+ mem->vaddr = NULL;
+}
+
+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(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(q->dev, "munmap %p q=%p\n", map, q);
+ videobuf_queue_lock(q);
+
+ /* 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(q->dev, "buf[%d] freeing %p\n",
+ i, mem->vaddr);
+
+ __videobuf_dc_free(q->dev, mem);
+ mem->vaddr = NULL;
+ }
+
+ q->bufs[i]->map = NULL;
+ q->bufs[i]->baddr = 0;
+ }
+
+ kfree(map);
+
+ videobuf_queue_unlock(q);
+ }
+}
+
+static const struct vm_operations_struct videobuf_vm_ops = {
+ .open = videobuf_vm_open,
+ .close = videobuf_vm_close,
+};
+
+/**
+ * videobuf_dma_contig_user_put() - reset pointer to user space buffer
+ * @mem: per-buffer private videobuf-dma-contig data
+ *
+ * This function resets the user space pointer
+ */
+static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem)
+{
+ mem->dma_handle = 0;
+ mem->size = 0;
+}
+
+/**
+ * videobuf_dma_contig_user_get() - setup user space memory pointer
+ * @mem: per-buffer private videobuf-dma-contig data
+ * @vb: video buffer to map
+ *
+ * This function validates and sets up a pointer to user space memory.
+ * Only physically contiguous pfn-mapped memory is accepted.
+ *
+ * Returns 0 if successful.
+ */
+static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
+ struct videobuf_buffer *vb)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long prev_pfn, this_pfn;
+ unsigned long pages_done, user_address;
+ unsigned int offset;
+ int ret;
+
+ offset = vb->baddr & ~PAGE_MASK;
+ mem->size = PAGE_ALIGN(vb->size + offset);
+ ret = -EINVAL;
+
+ down_read(&mm->mmap_sem);
+
+ vma = find_vma(mm, vb->baddr);
+ if (!vma)
+ goto out_up;
+
+ if ((vb->baddr + mem->size) > vma->vm_end)
+ goto out_up;
+
+ pages_done = 0;
+ prev_pfn = 0; /* kill warning */
+ user_address = vb->baddr;
+
+ while (pages_done < (mem->size >> PAGE_SHIFT)) {
+ ret = follow_pfn(vma, user_address, &this_pfn);
+ if (ret)
+ break;
+
+ if (pages_done == 0)
+ mem->dma_handle = (this_pfn << PAGE_SHIFT) + offset;
+ else if (this_pfn != (prev_pfn + 1))
+ ret = -EFAULT;
+
+ if (ret)
+ break;
+
+ prev_pfn = this_pfn;
+ user_address += PAGE_SIZE;
+ pages_done++;
+ }
+
+out_up:
+ up_read(¤t->mm->mmap_sem);
+
+ return ret;
+}
+
+static struct videobuf_buffer *__videobuf_alloc(size_t size)
+{
+ struct videobuf_dma_contig_memory *mem;
+ struct videobuf_buffer *vb;
+
+ vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
+ if (vb) {
+ vb->priv = ((char *)vb) + size;
+ mem = vb->priv;
+ mem->magic = MAGIC_DC_MEM;
+ }
+
+ return vb;
+}
+
+static void *__videobuf_to_vaddr(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__);
+
+ /* handle pointer from user space */
+ if (vb->baddr)
+ return videobuf_dma_contig_user_get(mem, vb);
+
+ /* allocate memory for the read() method */
+ if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(vb->size),
+ GFP_KERNEL))
+ return -ENOMEM;
+ break;
+ case V4L2_MEMORY_OVERLAY:
+ default:
+ dev_dbg(q->dev, "%s memory method OVERLAY/unknown\n", __func__);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int __videobuf_mmap_mapper(struct videobuf_queue *q,
+ struct videobuf_buffer *buf,
+ struct vm_area_struct *vma)
+{
+ struct videobuf_dma_contig_memory *mem;
+ struct videobuf_mapping *map;
+ int retval;
+ unsigned long size;
+
+ dev_dbg(q->dev, "%s\n", __func__);
+
+ /* create mapping + update buffer list */
+ map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
+ if (!map)
+ return -ENOMEM;
+
+ buf->map = map;
+ map->q = q;
+
+ buf->baddr = vma->vm_start;
+
+ mem = buf->priv;
+ BUG_ON(!mem);
+ MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
+
+ if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(buf->bsize),
+ GFP_KERNEL | __GFP_COMP))
+ goto error;
+
+ /* Try to remap memory */
+ size = vma->vm_end - vma->vm_start;
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+ /* the "vm_pgoff" is just used in v4l2 to find the
+ * corresponding buffer data structure which is allocated
+ * earlier and it does not mean the offset from the physical
+ * buffer start address as usual. So set it to 0 to pass
+ * the sanity check in vm_iomap_memory().
+ */
+ vma->vm_pgoff = 0;
+
+ retval = vm_iomap_memory(vma, mem->dma_handle, size);
+ 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)buf->bsize, vma->vm_pgoff, buf->i);
+
+ videobuf_vm_open(vma);
+
+ return 0;
+
+error:
+ kfree(map);
+ return -ENOMEM;
+}
+
+static struct videobuf_qtype_ops qops = {
+ .magic = MAGIC_QTYPE_OPS,
+ .alloc_vb = __videobuf_alloc,
+ .iolock = __videobuf_iolock,
+ .mmap_mapper = __videobuf_mmap_mapper,
+ .vaddr = __videobuf_to_vaddr,
+};
+
+void videobuf_queue_dma_contig_init(struct videobuf_queue *q,
+ const 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,
+ struct mutex *ext_lock)
+{
+ videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
+ priv, &qops, ext_lock);
+}
+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)
+ return;
+
+ if (!mem)
+ return;
+
+ MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
+
+ /* handle user space pointer case */
+ if (buf->baddr) {
+ videobuf_dma_contig_user_put(mem);
+ return;
+ }
+
+ /* read() method */
+ if (mem->vaddr) {
+ __videobuf_dc_free(q->dev, mem);
+ 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");
Code Review / kvmfornfv.git / blobdiff