[deliverable/linux.git] / drivers / media / video / videobuf2-memops.c

/*
 * 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-core.h>
#include <media/videobuf2-memops.h>

/**
 * vb2_get_vma() - acquire and lock the virtual memory area
 * @vma:	given virtual memory area
 *
 * This function attempts to acquire an area mapped in the userspace for
 * the duration of a hardware operation. The area is "locked" by performing
 * the same set of operation that are done when process calls fork() and
 * memory areas are duplicated.
 *
 * Returns a copy of a virtual memory region on success or NULL.
 */
struct vm_area_struct *vb2_get_vma(struct vm_area_struct *vma)
{
	struct vm_area_struct *vma_copy;

	vma_copy = kmalloc(sizeof(*vma_copy), GFP_KERNEL);
	if (vma_copy == NULL)
		return NULL;

	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));

	vma_copy->vm_mm = NULL;
	vma_copy->vm_next = NULL;
	vma_copy->vm_prev = NULL;

	return vma_copy;
}

/**
 * vb2_put_userptr() - release a userspace virtual 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_vma(struct vm_area_struct *vma)
{
	if (!vma)
		return;

	if (vma->vm_ops && vma->vm_ops->close)
		vma->vm_ops->close(vma);

	if (vma->vm_file)
		fput(vma->vm_file);

	kfree(vma);
}
EXPORT_SYMBOL_GPL(vb2_put_vma);

/**
 * vb2_get_contig_userptr() - lock physically contiguous userspace mapped memory
 * @vaddr:	starting virtual address of the area to be verified
 * @size:	size of the area
 * @res_paddr:	will return physical address for the given vaddr
 * @res_vma:	will return locked copy of struct vm_area for the given area
 *
 * This function will go through memory area of size @size mapped at @vaddr and
 * verify that the underlying physical pages are contiguous. If they are
 * contiguous the virtual memory area is locked and a @res_vma is filled with
 * the copy and @res_pa set to the physical address of the buffer.
 *
 * Returns 0 on success.
 */
int vb2_get_contig_userptr(unsigned long vaddr, unsigned long size,
			   struct vm_area_struct **res_vma, dma_addr_t *res_pa)
{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	unsigned long offset, start, end;
	unsigned long this_pfn, prev_pfn;
	dma_addr_t pa = 0;
	int ret = -EFAULT;

	start = vaddr;
	offset = start & ~PAGE_MASK;
	end = start + size;

	down_read(&mm->mmap_sem);
	vma = find_vma(mm, start);

	if (vma == NULL || vma->vm_end < end)
		goto done;

	for (prev_pfn = 0; start < end; start += PAGE_SIZE) {
		ret = follow_pfn(vma, start, &this_pfn);
		if (ret)
			goto done;

		if (prev_pfn == 0)
			pa = this_pfn << PAGE_SHIFT;
		else if (this_pfn != prev_pfn + 1) {
			ret = -EFAULT;
			goto done;
		}
		prev_pfn = this_pfn;
	}

	/*
	 * Memory is contigous, lock vma and return to the caller
	 */
	*res_vma = vb2_get_vma(vma);
	if (*res_vma == NULL) {
		ret = -ENOMEM;
		goto done;
	}
	*res_pa = pa + offset;
	ret = 0;

done:
	up_read(&mm->mmap_sem);
	return ret;
}
EXPORT_SYMBOL_GPL(vb2_get_contig_userptr);

/**
 * 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;

	vma->vm_ops->open(vma);

	pr_debug("%s: mapped paddr 0x%08lx at 0x%08lx, size %ld\n",
			__func__, paddr, vma->vm_start, size);

	return 0;
}
EXPORT_SYMBOL_GPL(vb2_mmap_pfn_range);

/**
 * 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, atomic_read(h->refcount), vma->vm_start,
	       vma->vm_end);

	atomic_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, atomic_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 mmaped
 * 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");
Commit	Line	Data
004cc378 MS	1	/*
	2	* videobuf2-memops.c - generic memory handling routines for videobuf2
	3	*
	4	* Copyright (C) 2010 Samsung Electronics
	5	*
95072084	6	* Author: Pawel Osciak <pawel@osciak.com>
004cc378 MS	7	* Marek Szyprowski <m.szyprowski@samsung.com>
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License as published by
	11	* the Free Software Foundation.
	12	*/
	13
	14	#include <linux/slab.h>
	15	#include <linux/module.h>
	16	#include <linux/dma-mapping.h>
	17	#include <linux/vmalloc.h>
	18	#include <linux/mm.h>
	19	#include <linux/sched.h>
	20	#include <linux/file.h>
004cc378 MS	21
	22	#include <media/videobuf2-core.h>
	23	#include <media/videobuf2-memops.h>
	24
	25	/**
	26	* vb2_get_vma() - acquire and lock the virtual memory area
	27	* @vma: given virtual memory area
	28	*
	29	* This function attempts to acquire an area mapped in the userspace for
	30	* the duration of a hardware operation. The area is "locked" by performing
	31	* the same set of operation that are done when process calls fork() and
	32	* memory areas are duplicated.
	33	*
	34	* Returns a copy of a virtual memory region on success or NULL.
	35	*/
	36	struct vm_area_struct vb2_get_vma(struct vm_area_struct vma)
	37	{
	38	struct vm_area_struct *vma_copy;
	39
	40	vma_copy = kmalloc(sizeof(*vma_copy), GFP_KERNEL);
	41	if (vma_copy == NULL)
	42	return NULL;
	43
	44	if (vma->vm_ops && vma->vm_ops->open)
	45	vma->vm_ops->open(vma);
	46
	47	if (vma->vm_file)
	48	get_file(vma->vm_file);
	49
	50	memcpy(vma_copy, vma, sizeof(*vma));
	51
	52	vma_copy->vm_mm = NULL;
	53	vma_copy->vm_next = NULL;
	54	vma_copy->vm_prev = NULL;
	55
	56	return vma_copy;
	57	}
	58
	59	/**
	60	* vb2_put_userptr() - release a userspace virtual memory area
	61	* @vma: virtual memory region associated with the area to be released
	62	*
	63	* This function releases the previously acquired memory area after a hardware
	64	* operation.
	65	*/
	66	void vb2_put_vma(struct vm_area_struct *vma)
	67	{
	68	if (!vma)
	69	return;
	70
004cc378 MS	71	if (vma->vm_ops && vma->vm_ops->close)
	72	vma->vm_ops->close(vma);
	73
8607c425 YT	74	if (vma->vm_file)
	75	fput(vma->vm_file);
	76
004cc378 MS	77	kfree(vma);
004cc378 MS	78	}
bd94f588	79	EXPORT_SYMBOL_GPL(vb2_put_vma);
004cc378 MS	80
	81	/**
	82	* vb2_get_contig_userptr() - lock physically contiguous userspace mapped memory
	83	* @vaddr: starting virtual address of the area to be verified
	84	* @size: size of the area
	85	* @res_paddr: will return physical address for the given vaddr
	86	* @res_vma: will return locked copy of struct vm_area for the given area
	87	*
	88	* This function will go through memory area of size @size mapped at @vaddr and
	89	* verify that the underlying physical pages are contiguous. If they are
	90	* contiguous the virtual memory area is locked and a @res_vma is filled with
	91	* the copy and @res_pa set to the physical address of the buffer.
	92	*
	93	* Returns 0 on success.
	94	*/
	95	int vb2_get_contig_userptr(unsigned long vaddr, unsigned long size,
	96	struct vm_area_struct *res_vma, dma_addr_t res_pa)
	97	{
	98	struct mm_struct *mm = current->mm;
	99	struct vm_area_struct *vma;
	100	unsigned long offset, start, end;
	101	unsigned long this_pfn, prev_pfn;
	102	dma_addr_t pa = 0;
	103	int ret = -EFAULT;
	104
	105	start = vaddr;
	106	offset = start & ~PAGE_MASK;
	107	end = start + size;
	108
	109	down_read(&mm->mmap_sem);
	110	vma = find_vma(mm, start);
	111
	112	if (vma == NULL \|\| vma->vm_end < end)
	113	goto done;
	114
	115	for (prev_pfn = 0; start < end; start += PAGE_SIZE) {
	116	ret = follow_pfn(vma, start, &this_pfn);
	117	if (ret)
	118	goto done;
	119
	120	if (prev_pfn == 0)
	121	pa = this_pfn << PAGE_SHIFT;
	122	else if (this_pfn != prev_pfn + 1) {
	123	ret = -EFAULT;
	124	goto done;
	125	}
	126	prev_pfn = this_pfn;
	127	}
	128
	129	/*
	130	* Memory is contigous, lock vma and return to the caller
	131	*/
	132	*res_vma = vb2_get_vma(vma);
	133	if (*res_vma == NULL) {
	134	ret = -ENOMEM;
	135	goto done;
	136	}
	137	*res_pa = pa + offset;
	138	ret = 0;
	139
	140	done:
	141	up_read(&mm->mmap_sem);
	142	return ret;
	143	}
bd94f588	144	EXPORT_SYMBOL_GPL(vb2_get_contig_userptr);
004cc378 MS	145
	146	/**
	147	* vb2_mmap_pfn_range() - map physical pages to userspace
	148	* @vma: virtual memory region for the mapping
	149	* @paddr: starting physical address of the memory to be mapped
	150	* @size: size of the memory to be mapped
	151	* @vm_ops: vm operations to be assigned to the created area
	152	* @priv: private data to be associated with the area
	153	*
	154	* Returns 0 on success.
	155	*/
	156	int vb2_mmap_pfn_range(struct vm_area_struct *vma, unsigned long paddr,
	157	unsigned long size,
	158	const struct vm_operations_struct *vm_ops,
	159	void *priv)
	160	{
	161	int ret;
	162
	163	size = min_t(unsigned long, vma->vm_end - vma->vm_start, size);
	164
	165	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
	166	ret = remap_pfn_range(vma, vma->vm_start, paddr >> PAGE_SHIFT,
	167	size, vma->vm_page_prot);
	168	if (ret) {
	169	printk(KERN_ERR "Remapping memory failed, error: %d\n", ret);
	170	return ret;
	171	}
	172
	173	vma->vm_flags \|= VM_DONTEXPAND \| VM_RESERVED;
	174	vma->vm_private_data = priv;
	175	vma->vm_ops = vm_ops;
	176
	177	vma->vm_ops->open(vma);
	178
7f116b3e	179	pr_debug("%s: mapped paddr 0x%08lx at 0x%08lx, size %ld\n",
004cc378 MS	180	__func__, paddr, vma->vm_start, size);
	181
	182	return 0;
	183	}
bd94f588	184	EXPORT_SYMBOL_GPL(vb2_mmap_pfn_range);
004cc378 MS	185
	186	/**
	187	* vb2_common_vm_open() - increase refcount of the vma
	188	* @vma: virtual memory region for the mapping
	189	*
	190	* This function adds another user to the provided vma. It expects
	191	* struct vb2_vmarea_handler pointer in vma->vm_private_data.
	192	*/
	193	static void vb2_common_vm_open(struct vm_area_struct *vma)
	194	{
	195	struct vb2_vmarea_handler *h = vma->vm_private_data;
	196
7f116b3e	197	pr_debug("%s: %p, refcount: %d, vma: %08lx-%08lx\n",
004cc378 MS	198	__func__, h, atomic_read(h->refcount), vma->vm_start,
	199	vma->vm_end);
	200
	201	atomic_inc(h->refcount);
	202	}
	203
	204	/**
	205	* vb2_common_vm_close() - decrease refcount of the vma
	206	* @vma: virtual memory region for the mapping
	207	*
	208	* This function releases the user from the provided vma. It expects
	209	* struct vb2_vmarea_handler pointer in vma->vm_private_data.
	210	*/
	211	static void vb2_common_vm_close(struct vm_area_struct *vma)
	212	{
	213	struct vb2_vmarea_handler *h = vma->vm_private_data;
	214
7f116b3e	215	pr_debug("%s: %p, refcount: %d, vma: %08lx-%08lx\n",
004cc378 MS	216	__func__, h, atomic_read(h->refcount), vma->vm_start,
	217	vma->vm_end);
	218
	219	h->put(h->arg);
	220	}
	221
	222	/**
	223	* vb2_common_vm_ops - common vm_ops used for tracking refcount of mmaped
	224	* video buffers
	225	*/
	226	const struct vm_operations_struct vb2_common_vm_ops = {
	227	.open = vb2_common_vm_open,
	228	.close = vb2_common_vm_close,
	229	};
	230	EXPORT_SYMBOL_GPL(vb2_common_vm_ops);
	231
	232	MODULE_DESCRIPTION("common memory handling routines for videobuf2");
95072084	233	MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
004cc378	234	MODULE_LICENSE("GPL");