From: Pawel Osciak <p.osciak@xxxxxxxxxxx>
Add generic memory handling routines for userspace pointer handling,
contiguous memory verification and mapping.
Signed-off-by: Pawel Osciak <p.osciak@xxxxxxxxxxx>
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
---
drivers/media/video/Kconfig | 3 +
drivers/media/video/Makefile | 1 +
drivers/media/video/videobuf2-memops.c | 194 ++++++++++++++++++++++++++++++++
include/media/videobuf2-memops.h | 31 +++++
4 files changed, 229 insertions(+), 0 deletions(-)
create mode 100644 drivers/media/video/videobuf2-memops.c
create mode 100644 include/media/videobuf2-memops.h
diff --git a/drivers/media/video/Kconfig b/drivers/media/video/Kconfig
index 9bf2fe1..2acb0f8 100644
--- a/drivers/media/video/Kconfig
+++ b/drivers/media/video/Kconfig
@@ -52,6 +52,9 @@ config V4L2_MEM2MEM_DEV
config VIDEOBUF2_CORE
tristate
+config VIDEOBUF2_MEMOPS
+ tristate
+
#
# Multimedia Video device configuration
#
diff --git a/drivers/media/video/Makefile b/drivers/media/video/Makefile
index e66f53b..77cc798 100644
--- a/drivers/media/video/Makefile
+++ b/drivers/media/video/Makefile
@@ -118,6 +118,7 @@ obj-$(CONFIG_VIDEOBUF_DVB) += videobuf-dvb.o
obj-$(CONFIG_VIDEO_BTCX) += btcx-risc.o
obj-$(CONFIG_VIDEOBUF2_CORE) += videobuf2-core.o
+obj-$(CONFIG_VIDEOBUF2_MEMOPS) += videobuf2-memops.o
obj-$(CONFIG_V4L2_MEM2MEM_DEV) += v4l2-mem2mem.o
diff --git a/drivers/media/video/videobuf2-memops.c b/drivers/media/video/videobuf2-memops.c
new file mode 100644
index 0000000..8b9d6e7
--- /dev/null
+++ b/drivers/media/video/videobuf2-memops.c
@@ -0,0 +1,194 @@
+/*
+ * videobuf2-memops.c - generic memory handling routines for videobuf2
+ *
+ * Copyright (C) 2010 Samsung Electronics
+ *
+ * Author: Pawel Osciak <p.osciak@xxxxxxxxxxx>
+ *
+ * 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/cma.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/file.h>
+
+#include <media/videobuf2-core.h>
+
+/**
+ * vb2_contig_verify_userptr() - verify contiguity of a userspace-mapped memory
+ * @vma: virtual memory region which maps the physical memory
+ * to be verified
+ * @vaddr: starting virtual address of the area to be verified
+ * @size: size of the area to be verified
+ * @paddr: will return physical address for the given vaddr
+ *
+ * This function will go through memory area of size size mapped at vaddr and
+ * verify that the underlying physical pages are contiguous.
+ *
+ * Returns 0 on success and a physical address to the memory pointed
+ * to by vaddr in paddr.
+ */
+int vb2_contig_verify_userptr(struct vm_area_struct *vma,
+ unsigned long vaddr, unsigned long size,
+ unsigned long *paddr)
+{
+ struct mm_struct *mm = current->mm;
+ unsigned long offset;
+ unsigned long vma_size;
+ unsigned long curr_pfn, prev_pfn;
+ unsigned long num_pages;
+ int ret = -EINVAL;
+ unsigned int i;
+
+ offset = vaddr & ~PAGE_MASK;
+
+ down_read(&mm->mmap_sem);
+
+ vma = find_vma(mm, vaddr);
+ if (!vma) {
+ printk(KERN_ERR "Invalid userspace address\n");
+ goto done;
+ }
+
+ vma_size = vma->vm_end - vma->vm_start;
+
+ if (size > vma_size - offset) {
+ printk(KERN_ERR "Region too small\n");
+ goto done;
+ }
+ num_pages = (size + offset) >> PAGE_SHIFT;
+
+ ret = follow_pfn(vma, vaddr, &curr_pfn);
+ if (ret) {
+ printk(KERN_ERR "Invalid userspace address\n");
+ goto done;
+ }
+
+ *paddr = (curr_pfn << PAGE_SHIFT) + offset;
+
+ for (i = 1; i < num_pages; ++i) {
+ prev_pfn = curr_pfn;
+ vaddr += PAGE_SIZE;
+
+ ret = follow_pfn(vma, vaddr, &curr_pfn);
+ if (ret || curr_pfn != prev_pfn + 1) {
+ printk(KERN_ERR "Invalid userspace address\n");
+ ret = -EINVAL;
+ break;
+ }
+ }
+
+done:
+ up_read(&mm->mmap_sem);
+ return ret;
+}
+
+/**
+ * vb2_mmap_pfn_range() - map physical pages to userspace
+ * @vma: virtual memory region for the mapping
+ * @paddr: starting physical address of the memory to be mapped
+ * @size: size of the memory to be mapped
+ * @vm_ops: vm operations to be assigned to the created area
+ * @priv: private data to be associated with the area
+ *
+ * Returns 0 on success.
+ */
+int vb2_mmap_pfn_range(struct vm_area_struct *vma, unsigned long paddr,
+ unsigned long size,
+ const struct vm_operations_struct *vm_ops,
+ void *priv)
+{
+ int ret;
+
+ size = min_t(unsigned long, vma->vm_end - vma->vm_start, size);
+
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+ ret = remap_pfn_range(vma, vma->vm_start, paddr >> PAGE_SHIFT,
+ size, vma->vm_page_prot);
+ if (ret) {
+ printk(KERN_ERR "Remapping memory failed, error: %d\n", ret);
+ return ret;
+ }
+
+ vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
+ vma->vm_private_data = priv;
+ vma->vm_ops = vm_ops;
+
+ vm_ops->open(vma);
+
+ printk(KERN_DEBUG "%s: mapped paddr 0x%08lx at 0x%08lx, size %ld\n",
+ __func__, paddr, vma->vm_start, size);
+
+ return 0;
+}
+
+/**
+ * vb2_get_userptr() - acquire an area pointed to by userspace addres vaddr
+ * @vaddr: virtual userspace address to the given area
+ *
+ * This function attempts to acquire an area mapped in the userspace for
+ * the duration of a hardware operation.
+ *
+ * Returns a virtual memory region associated with the given vaddr on success
+ * or NULL.
+ */
+struct vm_area_struct *vb2_get_userptr(unsigned long vaddr)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ struct vm_area_struct *vma_copy;
+
+ vma_copy = kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
+ if (vma_copy == NULL)
+ return NULL;
+
+ down_read(&mm->mmap_sem);
+
+ vma = find_vma(mm, vaddr);
+ if (!vma)
+ goto done;
+
+ if (vma->vm_ops && vma->vm_ops->open)
+ vma->vm_ops->open(vma);
+
+ if (vma->vm_file)
+ get_file(vma->vm_file);
+
+ memcpy(vma_copy, vma, sizeof(*vma));
+done:
+ up_read(&mm->mmap_sem);
+
+ vma_copy->vm_mm = NULL;
+ vma_copy->vm_next = NULL;
+ vma_copy->vm_prev = NULL;
+
+ return vma_copy;
+}
+
+/**
+ * vb2_put_userptr() - release a userspace memory area
+ * @vma: virtual memory region associated with the area to be released
+ *
+ * This function releases the previously acquired memory area after a hardware
+ * operation.
+ */
+void vb2_put_userptr(struct vm_area_struct *vma)
+{
+ if (!vma)
+ return;
+
+ if (vma->vm_file)
+ fput(vma->vm_file);
+
+ if (vma->vm_ops && vma->vm_ops->close)
+ vma->vm_ops->close(vma);
+
+ kfree(vma);
+}
diff --git a/include/media/videobuf2-memops.h b/include/media/videobuf2-memops.h
new file mode 100644
index 0000000..3257411
--- /dev/null
+++ b/include/media/videobuf2-memops.h
@@ -0,0 +1,31 @@
+/*
+ * videobuf2-memops.h - generic memory handling routines for videobuf2
+ *
+ * Copyright (C) 2010 Samsung Electronics
+ *
+ * Author: Pawel Osciak <p.osciak@xxxxxxxxxxx>
+ *
+ * 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.
+ */
+
+#ifndef _MEDIA_VIDEOBUF2_MEMOPS_H
+#define _MEDIA_VIDEOBUF2_MEMOPS_H
+
+#include <media/videobuf2-core.h>
+
+int vb2_contig_verify_userptr(struct vm_area_struct *vma,
+ unsigned long vaddr, unsigned long size,
+ unsigned long *paddr);
+
+int vb2_mmap_pfn_range(struct vm_area_struct *vma, unsigned long paddr,
+ unsigned long size,
+ const struct vm_operations_struct *vm_ops,
+ void *priv);
+
+struct vm_area_struct *vb2_get_userptr(unsigned long vaddr);
+
+void vb2_put_userptr(struct vm_area_struct *vma);
+
+#endif
--
1.7.1.569.g6f426
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