drivers/media/v4l2-core/videobuf-vmalloc.c - linux - Git at Google

 /*
  * helper functions for vmalloc video4linux capture buffers
  *
  * The functions expect the hardware being able to scatter gather
  * (i.e. the buffers are not linear in physical memory, but fragmented
  * into PAGE_SIZE chunks).  They also assume the driver does not need
  * to touch the video data.
  *
  * (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.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/moduleparam.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>

 #include <linux/pci.h>
 #include <linux/vmalloc.h>
 #include <linux/pagemap.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>

 #include <media/videobuf-vmalloc.h>

 #define MAGIC_DMABUF   0x17760309
 #define MAGIC_VMAL_MEM 0x18221223

 #define MAGIC_CHECK(is, should)						\
 	if (unlikely((is) != (should))) {				\
 		printk(KERN_ERR "magic mismatch: %x (expected %x)\n",	\
 				is, should);				\
 		BUG();							\
 	}

 static int debug;
 module_param(debug, int, 0644);

 MODULE_DESCRIPTION("helper module to manage video4linux vmalloc buffers");
 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@kernel.org>");
 MODULE_LICENSE("GPL");

 #define dprintk(level, fmt, arg...)					\
 	if (debug >= level)						\
 		printk(KERN_DEBUG "vbuf-vmalloc: " fmt , ## arg)


 /***************************************************************************/

 static void videobuf_vm_open(struct vm_area_struct *vma)
 {
 	struct videobuf_mapping *map = vma->vm_private_data;

 	dprintk(2, "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;

 	dprintk(2, "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_vmalloc_memory *mem;

 		dprintk(1, "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_VMAL_MEM);

 				/* vfree is not atomic - can't be
 				   called with IRQ's disabled
 				 */
 				dprintk(1, "%s: buf[%d] freeing (%p)\n",
 					__func__, i, mem->vaddr);

 				vfree(mem->vaddr);
 				mem->vaddr = NULL;
 			}

 			q->bufs[i]->map   = NULL;
 			q->bufs[i]->baddr = 0;
 		}

 		kfree(map);

 		videobuf_queue_unlock(q);
 	}

 	return;
 }

 static const struct vm_operations_struct videobuf_vm_ops = {
 	.open     = videobuf_vm_open,
 	.close    = videobuf_vm_close,
 };

 /* ---------------------------------------------------------------------
  * vmalloc handlers for the generic methods
  */

 /* Allocated area consists on 3 parts:
 	struct video_buffer
 	struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
 	struct videobuf_dma_sg_memory
  */

 static struct videobuf_buffer *__videobuf_alloc_vb(size_t size)
 {
 	struct videobuf_vmalloc_memory *mem;
 	struct videobuf_buffer *vb;

 	vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
 	if (!vb)
 		return vb;

 	mem = vb->priv = ((char *)vb) + size;
 	mem->magic = MAGIC_VMAL_MEM;

 	dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
 		__func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb),
 		mem, (long)sizeof(*mem));

 	return vb;
 }

 static int __videobuf_iolock(struct videobuf_queue *q,
 			     struct videobuf_buffer *vb,
 			     struct v4l2_framebuffer *fbuf)
 {
 	struct videobuf_vmalloc_memory *mem = vb->priv;
 	int pages;

 	BUG_ON(!mem);

 	MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);

 	switch (vb->memory) {
 	case V4L2_MEMORY_MMAP:
 		dprintk(1, "%s memory method MMAP\n", __func__);

 		/* All handling should be done by __videobuf_mmap_mapper() */
 		if (!mem->vaddr) {
 			printk(KERN_ERR "memory is not alloced/mmapped.\n");
 			return -EINVAL;
 		}
 		break;
 	case V4L2_MEMORY_USERPTR:
 		pages = PAGE_ALIGN(vb->size);

 		dprintk(1, "%s memory method USERPTR\n", __func__);

 		if (vb->baddr) {
 			printk(KERN_ERR "USERPTR is currently not supported\n");
 			return -EINVAL;
 		}

 		/* The only USERPTR currently supported is the one needed for
 		 * read() method.
 		 */

 		mem->vaddr = vmalloc_user(pages);
 		if (!mem->vaddr) {
 			printk(KERN_ERR "vmalloc (%d pages) failed\n", pages);
 			return -ENOMEM;
 		}
 		dprintk(1, "vmalloc is at addr %p (%d pages)\n",
 			mem->vaddr, pages);

 #if 0
 		int rc;
 		/* Kernel userptr is used also by read() method. In this case,
 		   there's no need to remap, since data will be copied to user
 		 */
 		if (!vb->baddr)
 			return 0;

 		/* FIXME: to properly support USERPTR, remap should occur.
 		   The code below won't work, since mem->vma = NULL
 		 */
 		/* Try to remap memory */
 		rc = remap_vmalloc_range(mem->vma, (void *)vb->baddr, 0);
 		if (rc < 0) {
 			printk(KERN_ERR "mmap: remap failed with error %d", rc);
 			return -ENOMEM;
 		}
 #endif

 		break;
 	case V4L2_MEMORY_OVERLAY:
 	default:
 		dprintk(1, "%s memory method OVERLAY/unknown\n", __func__);

 		/* Currently, doesn't support V4L2_MEMORY_OVERLAY */
 		printk(KERN_ERR "Memory method currently unsupported.\n");
 		return -EINVAL;
 	}

 	return 0;
 }

 static int __videobuf_mmap_mapper(struct videobuf_queue *q,
 				  struct videobuf_buffer *buf,
 				  struct vm_area_struct *vma)
 {
 	struct videobuf_vmalloc_memory *mem;
 	struct videobuf_mapping *map;
 	int retval, pages;

 	dprintk(1, "%s\n", __func__);

 	/* create mapping + update buffer list */
 	map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
 	if (NULL == 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_VMAL_MEM);

 	pages = PAGE_ALIGN(vma->vm_end - vma->vm_start);
 	mem->vaddr = vmalloc_user(pages);
 	if (!mem->vaddr) {
 		printk(KERN_ERR "vmalloc (%d pages) failed\n", pages);
 		goto error;
 	}
 	dprintk(1, "vmalloc is at addr %p (%d pages)\n", mem->vaddr, pages);

 	/* Try to remap memory */
 	retval = remap_vmalloc_range(vma, mem->vaddr, 0);
 	if (retval < 0) {
 		printk(KERN_ERR "mmap: remap failed with error %d. ", retval);
 		vfree(mem->vaddr);
 		goto error;
 	}

 	vma->vm_ops          = &videobuf_vm_ops;
 	vma->vm_flags       |= VM_DONTEXPAND | VM_DONTDUMP;
 	vma->vm_private_data = map;

 	dprintk(1, "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:
 	mem = NULL;
 	kfree(map);
 	return -ENOMEM;
 }

 static struct videobuf_qtype_ops qops = {
 	.magic        = MAGIC_QTYPE_OPS,

 	.alloc_vb     = __videobuf_alloc_vb,
 	.iolock       = __videobuf_iolock,
 	.mmap_mapper  = __videobuf_mmap_mapper,
 	.vaddr        = videobuf_to_vmalloc,
 };

 void videobuf_queue_vmalloc_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_vmalloc_init);

 void *videobuf_to_vmalloc(struct videobuf_buffer *buf)
 {
 	struct videobuf_vmalloc_memory *mem = buf->priv;
 	BUG_ON(!mem);
 	MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);

 	return mem->vaddr;
 }
 EXPORT_SYMBOL_GPL(videobuf_to_vmalloc);

 void videobuf_vmalloc_free(struct videobuf_buffer *buf)
 {
 	struct videobuf_vmalloc_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_VMAL_MEM);

 	vfree(mem->vaddr);
 	mem->vaddr = NULL;

 	return;
 }
 EXPORT_SYMBOL_GPL(videobuf_vmalloc_free);
	/*
	* helper functions for vmalloc video4linux capture buffers
	*
	* The functions expect the hardware being able to scatter gather
	* (i.e. the buffers are not linear in physical memory, but fragmented
	* into PAGE_SIZE chunks). They also assume the driver does not need
	* to touch the video data.
	*
	* (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.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/moduleparam.h>
	#include <linux/slab.h>
	#include <linux/interrupt.h>

	#include <linux/pci.h>
	#include <linux/vmalloc.h>
	#include <linux/pagemap.h>
	#include <asm/page.h>
	#include <asm/pgtable.h>

	#include <media/videobuf-vmalloc.h>

	#define MAGIC_DMABUF 0x17760309
	#define MAGIC_VMAL_MEM 0x18221223

	#define MAGIC_CHECK(is, should) \
	if (unlikely((is) != (should))) { \
	printk(KERN_ERR "magic mismatch: %x (expected %x)\n", \
	is, should); \
	BUG(); \
	}

	static int debug;
	module_param(debug, int, 0644);

	MODULE_DESCRIPTION("helper module to manage video4linux vmalloc buffers");
	MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@kernel.org>");
	MODULE_LICENSE("GPL");

	#define dprintk(level, fmt, arg...) \
	if (debug >= level) \
	printk(KERN_DEBUG "vbuf-vmalloc: " fmt , ## arg)


	/***************************************************************************/

	static void videobuf_vm_open(struct vm_area_struct *vma)
	{
	struct videobuf_mapping *map = vma->vm_private_data;

	dprintk(2, "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;

	dprintk(2, "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_vmalloc_memory *mem;

	dprintk(1, "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_VMAL_MEM);

	/* vfree is not atomic - can't be
	called with IRQ's disabled
	*/
	dprintk(1, "%s: buf[%d] freeing (%p)\n",
	__func__, i, mem->vaddr);

	vfree(mem->vaddr);
	mem->vaddr = NULL;
	}

	q->bufs[i]->map = NULL;
	q->bufs[i]->baddr = 0;
	}

	kfree(map);

	videobuf_queue_unlock(q);
	}

	return;
	}

	static const struct vm_operations_struct videobuf_vm_ops = {
	.open = videobuf_vm_open,
	.close = videobuf_vm_close,
	};

	/* ---------------------------------------------------------------------
	* vmalloc handlers for the generic methods
	*/

	/* Allocated area consists on 3 parts:
	struct video_buffer
	struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
	struct videobuf_dma_sg_memory
	*/

	static struct videobuf_buffer *__videobuf_alloc_vb(size_t size)
	{
	struct videobuf_vmalloc_memory *mem;
	struct videobuf_buffer *vb;

	vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
	if (!vb)
	return vb;

	mem = vb->priv = ((char *)vb) + size;
	mem->magic = MAGIC_VMAL_MEM;

	dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
	__func__, vb, (long)sizeof(vb), (long)size - sizeof(vb),
	mem, (long)sizeof(*mem));

	return vb;
	}

	static int __videobuf_iolock(struct videobuf_queue *q,
	struct videobuf_buffer *vb,
	struct v4l2_framebuffer *fbuf)
	{
	struct videobuf_vmalloc_memory *mem = vb->priv;
	int pages;

	BUG_ON(!mem);

	MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);

	switch (vb->memory) {
	case V4L2_MEMORY_MMAP:
	dprintk(1, "%s memory method MMAP\n", __func__);

	/* All handling should be done by __videobuf_mmap_mapper() */
	if (!mem->vaddr) {
	printk(KERN_ERR "memory is not alloced/mmapped.\n");
	return -EINVAL;
	}
	break;
	case V4L2_MEMORY_USERPTR:
	pages = PAGE_ALIGN(vb->size);

	dprintk(1, "%s memory method USERPTR\n", __func__);

	if (vb->baddr) {
	printk(KERN_ERR "USERPTR is currently not supported\n");
	return -EINVAL;
	}

	/* The only USERPTR currently supported is the one needed for
	* read() method.
	*/

	mem->vaddr = vmalloc_user(pages);
	if (!mem->vaddr) {
	printk(KERN_ERR "vmalloc (%d pages) failed\n", pages);
	return -ENOMEM;
	}
	dprintk(1, "vmalloc is at addr %p (%d pages)\n",
	mem->vaddr, pages);

	#if 0
	int rc;
	/* Kernel userptr is used also by read() method. In this case,
	there's no need to remap, since data will be copied to user
	*/
	if (!vb->baddr)
	return 0;

	/* FIXME: to properly support USERPTR, remap should occur.
	The code below won't work, since mem->vma = NULL
	*/
	/* Try to remap memory */
	rc = remap_vmalloc_range(mem->vma, (void *)vb->baddr, 0);
	if (rc < 0) {
	printk(KERN_ERR "mmap: remap failed with error %d", rc);
	return -ENOMEM;
	}
	#endif

	break;
	case V4L2_MEMORY_OVERLAY:
	default:
	dprintk(1, "%s memory method OVERLAY/unknown\n", __func__);

	/* Currently, doesn't support V4L2_MEMORY_OVERLAY */
	printk(KERN_ERR "Memory method currently unsupported.\n");
	return -EINVAL;
	}

	return 0;
	}

	static int __videobuf_mmap_mapper(struct videobuf_queue *q,
	struct videobuf_buffer *buf,
	struct vm_area_struct *vma)
	{
	struct videobuf_vmalloc_memory *mem;
	struct videobuf_mapping *map;
	int retval, pages;

	dprintk(1, "%s\n", __func__);

	/* create mapping + update buffer list */
	map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
	if (NULL == 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_VMAL_MEM);

	pages = PAGE_ALIGN(vma->vm_end - vma->vm_start);
	mem->vaddr = vmalloc_user(pages);
	if (!mem->vaddr) {
	printk(KERN_ERR "vmalloc (%d pages) failed\n", pages);
	goto error;
	}
	dprintk(1, "vmalloc is at addr %p (%d pages)\n", mem->vaddr, pages);

	/* Try to remap memory */
	retval = remap_vmalloc_range(vma, mem->vaddr, 0);
	if (retval < 0) {
	printk(KERN_ERR "mmap: remap failed with error %d. ", retval);
	vfree(mem->vaddr);
	goto error;
	}

	vma->vm_ops = &videobuf_vm_ops;
	vma->vm_flags \|= VM_DONTEXPAND \| VM_DONTDUMP;
	vma->vm_private_data = map;

	dprintk(1, "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:
	mem = NULL;
	kfree(map);
	return -ENOMEM;
	}

	static struct videobuf_qtype_ops qops = {
	.magic = MAGIC_QTYPE_OPS,

	.alloc_vb = __videobuf_alloc_vb,
	.iolock = __videobuf_iolock,
	.mmap_mapper = __videobuf_mmap_mapper,
	.vaddr = videobuf_to_vmalloc,
	};

	void videobuf_queue_vmalloc_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_vmalloc_init);

	void videobuf_to_vmalloc(struct videobuf_buffer buf)
	{
	struct videobuf_vmalloc_memory *mem = buf->priv;
	BUG_ON(!mem);
	MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);

	return mem->vaddr;
	}
	EXPORT_SYMBOL_GPL(videobuf_to_vmalloc);

	void videobuf_vmalloc_free(struct videobuf_buffer *buf)
	{
	struct videobuf_vmalloc_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_VMAL_MEM);

	vfree(mem->vaddr);
	mem->vaddr = NULL;

	return;
	}
	EXPORT_SYMBOL_GPL(videobuf_vmalloc_free);