V4L/DVB (6254): Add videobuf-vmalloc

Adds a newer videobuf-vmalloc module. This module uses the same
videobuf controls, but implements memory allocation based on vmalloc
methods.

With this method, an USB driver can use video-buf, without needing to
request memory from the DMA-safe area.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 384 insertions, 0 deletions

diff --git a/drivers/media/video/videobuf-vmalloc.c b/drivers/media/video/videobuf-vmalloc.c
new file mode 100644
index 000000000000..993d5285e18e
--- /dev/null
+++ b/drivers/media/video/videobuf-vmalloc.c
@@ -0,0 +1,384 @@
+/*
+ * helper functions for vmalloc video4linux capture buffers
+ *
+ * The functions expect the hardware being able to scatter gatter
+ * (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@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/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 = 0;
+module_param(debug, int, 0644);
+
+MODULE_DESCRIPTION("helper module to manage video4linux vmalloc buffers");
+MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
+MODULE_LICENSE("GPL");
+
+#define dprintk(level, fmt, arg...)	if (debug >= level) \
+	printk(KERN_DEBUG "vbuf-sg: " 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=%d,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;
+	struct videbuf_vmalloc_memory *mem;
+	int i;
+
+	dprintk(2,"vm_close %p [count=%d,vma=%08lx-%08lx]\n",map,
+		map->count,vma->vm_start,vma->vm_end);
+
+	map->count--;
+	if (0 == map->count) {
+		dprintk(1,"munmap %p q=%p\n",map,q);
+		mutex_lock(&q->lock);
+		for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+			if (NULL == q->bufs[i])
+				continue;
+			mem=q->bufs[i]->priv;
+
+			if (!mem)
+				continue;
+
+			MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
+
+			if (mem->map != map)
+				continue;
+			mem->map   = NULL;
+			q->bufs[i]->baddr = 0;
+			q->ops->buf_release(q,q->bufs[i]);
+		}
+		mutex_unlock(&q->lock);
+		kfree(map);
+	}
+	return;
+}
+
+static 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_pci_sg_memory
+ */
+
+static void *__videobuf_alloc(size_t size)
+{
+	struct videbuf_vmalloc_memory *mem;
+	struct videobuf_buffer *vb;
+
+	vb = kzalloc(size+sizeof(*mem),GFP_KERNEL);
+
+	mem = vb->priv = ((char *)vb)+size;
+	mem->magic=MAGIC_VMAL_MEM;
+
+	dprintk(1,"%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
+		__FUNCTION__,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)
+{
+	int pages;
+
+	struct videbuf_vmalloc_memory *mem=vb->priv;
+
+
+	BUG_ON(!mem);
+
+	MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
+
+
+	pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
+
+	/* Currently, doesn't support V4L2_MEMORY_OVERLAY */
+	if ((vb->memory != V4L2_MEMORY_MMAP) &&
+				(vb->memory != V4L2_MEMORY_USERPTR) ) {
+		printk(KERN_ERR "Method currently unsupported.\n");
+		return -EINVAL;
+	}
+
+	/* FIXME: should be tested with kernel mmap mem */
+	mem->vmalloc=vmalloc_user (PAGE_ALIGN(vb->size));
+	if (NULL == mem->vmalloc) {
+		dprintk(1,"vmalloc (%d pages) failed\n",pages);
+		return -ENOMEM;
+	}
+
+	dprintk(1,"vmalloc is at addr 0x%08lx, size=%d\n",
+				(unsigned long)mem->vmalloc,
+				pages << PAGE_SHIFT);
+
+	/* It seems that some kernel versions need to do remap *after*
+	   the mmap() call
+	 */
+	if (mem->vma) {
+		int retval=remap_vmalloc_range(mem->vma, mem->vmalloc,0);
+		kfree(mem->vma);
+		mem->vma=NULL;
+		if (retval<0) {
+			dprintk(1,"mmap app bug: remap_vmalloc_range area %p error %d\n",
+				mem->vmalloc,retval);
+			return retval;
+		}
+	}
+
+	return 0;
+}
+
+static int __videobuf_sync(struct videobuf_queue *q,
+			   struct videobuf_buffer *buf)
+{
+	return 0;
+}
+
+static int __videobuf_mmap_free(struct videobuf_queue *q)
+{
+	unsigned int i;
+
+	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+		if (q->bufs[i]) {
+			struct videbuf_vmalloc_memory *mem=q->bufs[i]->priv;
+			if (mem && mem->map)
+				return -EBUSY;
+		}
+	}
+
+	return 0;
+}
+
+static int __videobuf_mmap_mapper(struct videobuf_queue *q,
+			 struct vm_area_struct *vma)
+{
+	struct videbuf_vmalloc_memory *mem;
+	struct videobuf_mapping *map;
+	unsigned int first;
+	int retval;
+	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
+
+	if (! (vma->vm_flags & VM_WRITE) || ! (vma->vm_flags & VM_SHARED))
+		return -EINVAL;
+
+	/* look for first buffer to map */
+	for (first = 0; first < VIDEO_MAX_FRAME; first++) {
+		if (NULL == q->bufs[first])
+			continue;
+
+		if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
+			continue;
+		if (q->bufs[first]->boff == offset)
+			break;
+	}
+	if (VIDEO_MAX_FRAME == first) {
+		dprintk(1,"mmap app bug: offset invalid [offset=0x%lx]\n",
+			(vma->vm_pgoff << PAGE_SHIFT));
+		return -EINVAL;
+	}
+	mem=q->bufs[first]->priv;
+	BUG_ON (!mem);
+	MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
+
+	/* create mapping + update buffer list */
+	map = mem->map = kmalloc(sizeof(struct videobuf_mapping),GFP_KERNEL);
+	if (NULL == map)
+		return -ENOMEM;
+
+	map->start = vma->vm_start;
+	map->end   = vma->vm_end;
+	map->q     = q;
+
+	q->bufs[first]->baddr = vma->vm_start;
+
+	vma->vm_ops          = &videobuf_vm_ops;
+	vma->vm_flags       |= VM_DONTEXPAND | VM_RESERVED;
+	vma->vm_private_data = map;
+
+	/* Try to remap memory */
+	retval=remap_vmalloc_range(vma, mem->vmalloc,0);
+	if (retval<0) {
+		dprintk(1,"mmap: postponing remap_vmalloc_range\n");
+		mem->vma=kmalloc(sizeof(*vma),GFP_KERNEL);
+		if (!mem->vma) {
+			kfree(map);
+			mem->map=NULL;
+			return -ENOMEM;
+		}
+		memcpy(mem->vma,vma,sizeof(*vma));
+	}
+
+	dprintk(1,"mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
+		map,q,vma->vm_start,vma->vm_end,
+		(long int) q->bufs[first]->bsize,
+		vma->vm_pgoff,first);
+
+	videobuf_vm_open(vma);
+
+	return (0);
+}
+
+static int __videobuf_is_mmapped (struct videobuf_buffer *buf)
+{
+	struct videbuf_vmalloc_memory *mem=buf->priv;
+	BUG_ON (!mem);
+	MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
+
+	return (mem->map)?1:0;
+}
+
+static int __videobuf_copy_to_user ( struct videobuf_queue *q,
+				char __user *data, size_t count,
+				int nonblocking )
+{
+	struct videbuf_vmalloc_memory *mem=q->read_buf->priv;
+	BUG_ON (!mem);
+	MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
+
+	BUG_ON (!mem->vmalloc);
+
+	/* copy to userspace */
+	if (count > q->read_buf->size - q->read_off)
+		count = q->read_buf->size - q->read_off;
+
+	if (copy_to_user(data, mem->vmalloc+q->read_off, count))
+		return -EFAULT;
+
+	return count;
+}
+
+static int __videobuf_copy_stream ( struct videobuf_queue *q,
+				char __user *data, size_t count, size_t pos,
+				int vbihack, int nonblocking )
+{
+	unsigned int  *fc;
+	struct videbuf_vmalloc_memory *mem=q->read_buf->priv;
+	BUG_ON (!mem);
+	MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
+
+	if (vbihack) {
+		/* dirty, undocumented hack -- pass the frame counter
+			* within the last four bytes of each vbi data block.
+			* We need that one to maintain backward compatibility
+			* to all vbi decoding software out there ... */
+		fc  = (unsigned int*)mem->vmalloc;
+		fc += (q->read_buf->size>>2) -1;
+		*fc = q->read_buf->field_count >> 1;
+		dprintk(1,"vbihack: %d\n",*fc);
+	}
+
+	/* copy stuff using the common method */
+	count = __videobuf_copy_to_user (q,data,count,nonblocking);
+
+	if ( (count==-EFAULT) && (0 == pos) )
+		return -EFAULT;
+
+	return count;
+}
+
+static struct videobuf_qtype_ops qops = {
+	.magic        = MAGIC_QTYPE_OPS,
+
+	.alloc        = __videobuf_alloc,
+	.iolock       = __videobuf_iolock,
+	.sync         = __videobuf_sync,
+	.mmap_free    = __videobuf_mmap_free,
+	.mmap_mapper  = __videobuf_mmap_mapper,
+	.is_mmapped   = __videobuf_is_mmapped,
+	.copy_to_user = __videobuf_copy_to_user,
+	.copy_stream  = __videobuf_copy_stream,
+};
+
+void videobuf_queue_vmalloc_init(struct videobuf_queue* q,
+			 struct videobuf_queue_ops *ops,
+			 void *dev,
+			 spinlock_t *irqlock,
+			 enum v4l2_buf_type type,
+			 enum v4l2_field field,
+			 unsigned int msize,
+			 void *priv)
+{
+	videobuf_queue_init(q, ops, dev, irqlock, type, field, msize, priv);
+	q->int_ops=&qops;
+}
+
+EXPORT_SYMBOL_GPL(videobuf_queue_vmalloc_init);
+
+void *videobuf_to_vmalloc (struct videobuf_buffer *buf)
+{
+	struct videbuf_vmalloc_memory *mem=buf->priv;
+	BUG_ON (!mem);
+	MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
+
+	return mem->vmalloc;
+}
+EXPORT_SYMBOL_GPL(videobuf_to_vmalloc);
+
+void videobuf_vmalloc_free (struct videobuf_buffer *buf)
+{
+	struct videbuf_vmalloc_memory *mem=buf->priv;
+	BUG_ON (!mem);
+
+	MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
+
+	vfree(mem->vmalloc);
+
+	return;
+}
+EXPORT_SYMBOL_GPL(videobuf_vmalloc_free);
+
+/*
+ * Local variables:
+ * c-basic-offset: 8
+ * End:
+ */