summaryrefslogtreecommitdiffstats
path: root/drivers/media/common/videobuf2/videobuf2-memops.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/media/common/videobuf2/videobuf2-memops.c')
-rw-r--r--drivers/media/common/videobuf2/videobuf2-memops.c131
1 files changed, 131 insertions, 0 deletions
diff --git a/drivers/media/common/videobuf2/videobuf2-memops.c b/drivers/media/common/videobuf2/videobuf2-memops.c
new file mode 100644
index 0000000000..f9a4ec4442
--- /dev/null
+++ b/drivers/media/common/videobuf2/videobuf2-memops.c
@@ -0,0 +1,131 @@
+/*
+ * videobuf2-memops.c - generic memory handling routines for videobuf2
+ *
+ * Copyright (C) 2010 Samsung Electronics
+ *
+ * Author: Pawel Osciak <pawel@osciak.com>
+ * Marek Szyprowski <m.szyprowski@samsung.com>
+ *
+ * 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.
+ */
+
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/dma-mapping.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/file.h>
+
+#include <media/videobuf2-v4l2.h>
+#include <media/videobuf2-memops.h>
+
+/**
+ * vb2_create_framevec() - map virtual addresses to pfns
+ * @start: Virtual user address where we start mapping
+ * @length: Length of a range to map
+ * @write: Should we map for writing into the area
+ *
+ * This function allocates and fills in a vector with pfns corresponding to
+ * virtual address range passed in arguments. If pfns have corresponding pages,
+ * page references are also grabbed to pin pages in memory. The function
+ * returns pointer to the vector on success and error pointer in case of
+ * failure. Returned vector needs to be freed via vb2_destroy_pfnvec().
+ */
+struct frame_vector *vb2_create_framevec(unsigned long start,
+ unsigned long length,
+ bool write)
+{
+ int ret;
+ unsigned long first, last;
+ unsigned long nr;
+ struct frame_vector *vec;
+
+ first = start >> PAGE_SHIFT;
+ last = (start + length - 1) >> PAGE_SHIFT;
+ nr = last - first + 1;
+ vec = frame_vector_create(nr);
+ if (!vec)
+ return ERR_PTR(-ENOMEM);
+ ret = get_vaddr_frames(start & PAGE_MASK, nr, write, vec);
+ if (ret < 0)
+ goto out_destroy;
+ /* We accept only complete set of PFNs */
+ if (ret != nr) {
+ ret = -EFAULT;
+ goto out_release;
+ }
+ return vec;
+out_release:
+ put_vaddr_frames(vec);
+out_destroy:
+ frame_vector_destroy(vec);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(vb2_create_framevec);
+
+/**
+ * vb2_destroy_framevec() - release vector of mapped pfns
+ * @vec: vector of pfns / pages to release
+ *
+ * This releases references to all pages in the vector @vec (if corresponding
+ * pfns are backed by pages) and frees the passed vector.
+ */
+void vb2_destroy_framevec(struct frame_vector *vec)
+{
+ put_vaddr_frames(vec);
+ frame_vector_destroy(vec);
+}
+EXPORT_SYMBOL(vb2_destroy_framevec);
+
+/**
+ * vb2_common_vm_open() - increase refcount of the vma
+ * @vma: virtual memory region for the mapping
+ *
+ * This function adds another user to the provided vma. It expects
+ * struct vb2_vmarea_handler pointer in vma->vm_private_data.
+ */
+static void vb2_common_vm_open(struct vm_area_struct *vma)
+{
+ struct vb2_vmarea_handler *h = vma->vm_private_data;
+
+ pr_debug("%s: %p, refcount: %d, vma: %08lx-%08lx\n",
+ __func__, h, refcount_read(h->refcount), vma->vm_start,
+ vma->vm_end);
+
+ refcount_inc(h->refcount);
+}
+
+/**
+ * vb2_common_vm_close() - decrease refcount of the vma
+ * @vma: virtual memory region for the mapping
+ *
+ * This function releases the user from the provided vma. It expects
+ * struct vb2_vmarea_handler pointer in vma->vm_private_data.
+ */
+static void vb2_common_vm_close(struct vm_area_struct *vma)
+{
+ struct vb2_vmarea_handler *h = vma->vm_private_data;
+
+ pr_debug("%s: %p, refcount: %d, vma: %08lx-%08lx\n",
+ __func__, h, refcount_read(h->refcount), vma->vm_start,
+ vma->vm_end);
+
+ h->put(h->arg);
+}
+
+/*
+ * vb2_common_vm_ops - common vm_ops used for tracking refcount of mmapped
+ * video buffers
+ */
+const struct vm_operations_struct vb2_common_vm_ops = {
+ .open = vb2_common_vm_open,
+ .close = vb2_common_vm_close,
+};
+EXPORT_SYMBOL_GPL(vb2_common_vm_ops);
+
+MODULE_DESCRIPTION("common memory handling routines for videobuf2");
+MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
+MODULE_LICENSE("GPL");