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linux-next/drivers/media/common/saa7146_fops.c
Hans Verkuil 5126f2590b [media] v4l2-dev: add flag to have the core lock all file operations
This used to be the default if the lock pointer was set, but now that lock is by
default only used for ioctl serialization. Those drivers that already used
core locking have this flag set explicitly, except for some drivers where
it was obvious that there was no need to serialize any file operations other
than ioctl.

The drivers that didn't need this flag were:

drivers/media/radio/dsbr100.c
drivers/media/radio/radio-isa.c
drivers/media/radio/radio-keene.c
drivers/media/radio/radio-miropcm20.c
drivers/media/radio/radio-mr800.c
drivers/media/radio/radio-tea5764.c
drivers/media/radio/radio-timb.c
drivers/media/video/vivi.c
sound/i2c/other/tea575x-tuner.c

The other drivers that use core locking and where it was not immediately
obvious that this flag wasn't needed were changed so that the flag is set
together with a comment that that driver needs work to avoid having to
set that flag. This will often involve taking the core lock in the fops
themselves.

Eventually this flag should go and it should not be used in new drivers.

There are a few reasons why we want to avoid core locking of non-ioctl
fops: in the case of mmap this can lead to a deadlock in rare situations
since when mmap is called the mmap_sem is held and it is possible for
other parts of the code to take that lock as well (copy_from_user()/copy_to_user()
perform a down_read(&mm->mmap_sem) when a page fault occurs).

It is very unlikely that that happens since the core lock serializes all
fops, but the kernel warns about it if lock validation is turned on.

For poll it is also undesirable to take the core lock as that can introduce
increased latency. The same is true for read/write.

While it was possible to make flags or something to turn on/off taking the
core lock for each file operation, in practice it is much simpler to just
not take it at all except for ioctl and leave it to the driver to take the
lock. There are only a handful fops compared to the zillion ioctls we have.

I also wanted to make it obvious which drivers still take the lock for all
fops, so that's why I chose to have drivers set it explicitly.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-05-14 09:19:38 -03:00

567 lines
14 KiB
C

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <media/saa7146_vv.h>
#include <linux/module.h>
/****************************************************************************/
/* resource management functions, shamelessly stolen from saa7134 driver */
int saa7146_res_get(struct saa7146_fh *fh, unsigned int bit)
{
struct saa7146_dev *dev = fh->dev;
struct saa7146_vv *vv = dev->vv_data;
if (fh->resources & bit) {
DEB_D("already allocated! want: 0x%02x, cur:0x%02x\n",
bit, vv->resources);
/* have it already allocated */
return 1;
}
/* is it free? */
if (vv->resources & bit) {
DEB_D("locked! vv->resources:0x%02x, we want:0x%02x\n",
vv->resources, bit);
/* no, someone else uses it */
return 0;
}
/* it's free, grab it */
fh->resources |= bit;
vv->resources |= bit;
DEB_D("res: get 0x%02x, cur:0x%02x\n", bit, vv->resources);
return 1;
}
void saa7146_res_free(struct saa7146_fh *fh, unsigned int bits)
{
struct saa7146_dev *dev = fh->dev;
struct saa7146_vv *vv = dev->vv_data;
BUG_ON((fh->resources & bits) != bits);
fh->resources &= ~bits;
vv->resources &= ~bits;
DEB_D("res: put 0x%02x, cur:0x%02x\n", bits, vv->resources);
}
/********************************************************************************/
/* common dma functions */
void saa7146_dma_free(struct saa7146_dev *dev,struct videobuf_queue *q,
struct saa7146_buf *buf)
{
struct videobuf_dmabuf *dma=videobuf_to_dma(&buf->vb);
DEB_EE("dev:%p, buf:%p\n", dev, buf);
BUG_ON(in_interrupt());
videobuf_waiton(q, &buf->vb, 0, 0);
videobuf_dma_unmap(q->dev, dma);
videobuf_dma_free(dma);
buf->vb.state = VIDEOBUF_NEEDS_INIT;
}
/********************************************************************************/
/* common buffer functions */
int saa7146_buffer_queue(struct saa7146_dev *dev,
struct saa7146_dmaqueue *q,
struct saa7146_buf *buf)
{
assert_spin_locked(&dev->slock);
DEB_EE("dev:%p, dmaq:%p, buf:%p\n", dev, q, buf);
BUG_ON(!q);
if (NULL == q->curr) {
q->curr = buf;
DEB_D("immediately activating buffer %p\n", buf);
buf->activate(dev,buf,NULL);
} else {
list_add_tail(&buf->vb.queue,&q->queue);
buf->vb.state = VIDEOBUF_QUEUED;
DEB_D("adding buffer %p to queue. (active buffer present)\n",
buf);
}
return 0;
}
void saa7146_buffer_finish(struct saa7146_dev *dev,
struct saa7146_dmaqueue *q,
int state)
{
assert_spin_locked(&dev->slock);
DEB_EE("dev:%p, dmaq:%p, state:%d\n", dev, q, state);
DEB_EE("q->curr:%p\n", q->curr);
BUG_ON(!q->curr);
/* finish current buffer */
if (NULL == q->curr) {
DEB_D("aiii. no current buffer\n");
return;
}
q->curr->vb.state = state;
do_gettimeofday(&q->curr->vb.ts);
wake_up(&q->curr->vb.done);
q->curr = NULL;
}
void saa7146_buffer_next(struct saa7146_dev *dev,
struct saa7146_dmaqueue *q, int vbi)
{
struct saa7146_buf *buf,*next = NULL;
BUG_ON(!q);
DEB_INT("dev:%p, dmaq:%p, vbi:%d\n", dev, q, vbi);
assert_spin_locked(&dev->slock);
if (!list_empty(&q->queue)) {
/* activate next one from queue */
buf = list_entry(q->queue.next,struct saa7146_buf,vb.queue);
list_del(&buf->vb.queue);
if (!list_empty(&q->queue))
next = list_entry(q->queue.next,struct saa7146_buf, vb.queue);
q->curr = buf;
DEB_INT("next buffer: buf:%p, prev:%p, next:%p\n",
buf, q->queue.prev, q->queue.next);
buf->activate(dev,buf,next);
} else {
DEB_INT("no next buffer. stopping.\n");
if( 0 != vbi ) {
/* turn off video-dma3 */
saa7146_write(dev,MC1, MASK_20);
} else {
/* nothing to do -- just prevent next video-dma1 transfer
by lowering the protection address */
// fixme: fix this for vflip != 0
saa7146_write(dev, PROT_ADDR1, 0);
saa7146_write(dev, MC2, (MASK_02|MASK_18));
/* write the address of the rps-program */
saa7146_write(dev, RPS_ADDR0, dev->d_rps0.dma_handle);
/* turn on rps */
saa7146_write(dev, MC1, (MASK_12 | MASK_28));
/*
printk("vdma%d.base_even: 0x%08x\n", 1,saa7146_read(dev,BASE_EVEN1));
printk("vdma%d.base_odd: 0x%08x\n", 1,saa7146_read(dev,BASE_ODD1));
printk("vdma%d.prot_addr: 0x%08x\n", 1,saa7146_read(dev,PROT_ADDR1));
printk("vdma%d.base_page: 0x%08x\n", 1,saa7146_read(dev,BASE_PAGE1));
printk("vdma%d.pitch: 0x%08x\n", 1,saa7146_read(dev,PITCH1));
printk("vdma%d.num_line_byte: 0x%08x\n", 1,saa7146_read(dev,NUM_LINE_BYTE1));
*/
}
del_timer(&q->timeout);
}
}
void saa7146_buffer_timeout(unsigned long data)
{
struct saa7146_dmaqueue *q = (struct saa7146_dmaqueue*)data;
struct saa7146_dev *dev = q->dev;
unsigned long flags;
DEB_EE("dev:%p, dmaq:%p\n", dev, q);
spin_lock_irqsave(&dev->slock,flags);
if (q->curr) {
DEB_D("timeout on %p\n", q->curr);
saa7146_buffer_finish(dev,q,VIDEOBUF_ERROR);
}
/* we don't restart the transfer here like other drivers do. when
a streaming capture is disabled, the timeout function will be
called for the current buffer. if we activate the next buffer now,
we mess up our capture logic. if a timeout occurs on another buffer,
then something is seriously broken before, so no need to buffer the
next capture IMHO... */
/*
saa7146_buffer_next(dev,q);
*/
spin_unlock_irqrestore(&dev->slock,flags);
}
/********************************************************************************/
/* file operations */
static int fops_open(struct file *file)
{
struct video_device *vdev = video_devdata(file);
struct saa7146_dev *dev = video_drvdata(file);
struct saa7146_fh *fh = NULL;
int result = 0;
enum v4l2_buf_type type;
DEB_EE("file:%p, dev:%s\n", file, video_device_node_name(vdev));
if (mutex_lock_interruptible(&saa7146_devices_lock))
return -ERESTARTSYS;
DEB_D("using: %p\n", dev);
type = vdev->vfl_type == VFL_TYPE_GRABBER
? V4L2_BUF_TYPE_VIDEO_CAPTURE
: V4L2_BUF_TYPE_VBI_CAPTURE;
/* check if an extension is registered */
if( NULL == dev->ext ) {
DEB_S("no extension registered for this device\n");
result = -ENODEV;
goto out;
}
/* allocate per open data */
fh = kzalloc(sizeof(*fh),GFP_KERNEL);
if (NULL == fh) {
DEB_S("cannot allocate memory for per open data\n");
result = -ENOMEM;
goto out;
}
file->private_data = fh;
fh->dev = dev;
fh->type = type;
if( fh->type == V4L2_BUF_TYPE_VBI_CAPTURE) {
DEB_S("initializing vbi...\n");
if (dev->ext_vv_data->capabilities & V4L2_CAP_VBI_CAPTURE)
result = saa7146_vbi_uops.open(dev,file);
if (dev->ext_vv_data->vbi_fops.open)
dev->ext_vv_data->vbi_fops.open(file);
} else {
DEB_S("initializing video...\n");
result = saa7146_video_uops.open(dev,file);
}
if (0 != result) {
goto out;
}
if( 0 == try_module_get(dev->ext->module)) {
result = -EINVAL;
goto out;
}
result = 0;
out:
if (fh && result != 0) {
kfree(fh);
file->private_data = NULL;
}
mutex_unlock(&saa7146_devices_lock);
return result;
}
static int fops_release(struct file *file)
{
struct saa7146_fh *fh = file->private_data;
struct saa7146_dev *dev = fh->dev;
DEB_EE("file:%p\n", file);
if (mutex_lock_interruptible(&saa7146_devices_lock))
return -ERESTARTSYS;
if( fh->type == V4L2_BUF_TYPE_VBI_CAPTURE) {
if (dev->ext_vv_data->capabilities & V4L2_CAP_VBI_CAPTURE)
saa7146_vbi_uops.release(dev,file);
if (dev->ext_vv_data->vbi_fops.release)
dev->ext_vv_data->vbi_fops.release(file);
} else {
saa7146_video_uops.release(dev,file);
}
module_put(dev->ext->module);
file->private_data = NULL;
kfree(fh);
mutex_unlock(&saa7146_devices_lock);
return 0;
}
static int fops_mmap(struct file *file, struct vm_area_struct * vma)
{
struct saa7146_fh *fh = file->private_data;
struct videobuf_queue *q;
switch (fh->type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE: {
DEB_EE("V4L2_BUF_TYPE_VIDEO_CAPTURE: file:%p, vma:%p\n",
file, vma);
q = &fh->video_q;
break;
}
case V4L2_BUF_TYPE_VBI_CAPTURE: {
DEB_EE("V4L2_BUF_TYPE_VBI_CAPTURE: file:%p, vma:%p\n",
file, vma);
q = &fh->vbi_q;
break;
}
default:
BUG();
return 0;
}
return videobuf_mmap_mapper(q,vma);
}
static unsigned int fops_poll(struct file *file, struct poll_table_struct *wait)
{
struct saa7146_fh *fh = file->private_data;
struct videobuf_buffer *buf = NULL;
struct videobuf_queue *q;
DEB_EE("file:%p, poll:%p\n", file, wait);
if (V4L2_BUF_TYPE_VBI_CAPTURE == fh->type) {
if( 0 == fh->vbi_q.streaming )
return videobuf_poll_stream(file, &fh->vbi_q, wait);
q = &fh->vbi_q;
} else {
DEB_D("using video queue\n");
q = &fh->video_q;
}
if (!list_empty(&q->stream))
buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
if (!buf) {
DEB_D("buf == NULL!\n");
return POLLERR;
}
poll_wait(file, &buf->done, wait);
if (buf->state == VIDEOBUF_DONE || buf->state == VIDEOBUF_ERROR) {
DEB_D("poll succeeded!\n");
return POLLIN|POLLRDNORM;
}
DEB_D("nothing to poll for, buf->state:%d\n", buf->state);
return 0;
}
static ssize_t fops_read(struct file *file, char __user *data, size_t count, loff_t *ppos)
{
struct saa7146_fh *fh = file->private_data;
switch (fh->type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
/*
DEB_EE("V4L2_BUF_TYPE_VIDEO_CAPTURE: file:%p, data:%p, count:%lun",
file, data, (unsigned long)count);
*/
return saa7146_video_uops.read(file,data,count,ppos);
case V4L2_BUF_TYPE_VBI_CAPTURE:
/*
DEB_EE("V4L2_BUF_TYPE_VBI_CAPTURE: file:%p, data:%p, count:%lu\n",
file, data, (unsigned long)count);
*/
if (fh->dev->ext_vv_data->capabilities & V4L2_CAP_VBI_CAPTURE)
return saa7146_vbi_uops.read(file,data,count,ppos);
return -EINVAL;
default:
BUG();
return 0;
}
}
static ssize_t fops_write(struct file *file, const char __user *data, size_t count, loff_t *ppos)
{
struct saa7146_fh *fh = file->private_data;
switch (fh->type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
return -EINVAL;
case V4L2_BUF_TYPE_VBI_CAPTURE:
if (fh->dev->ext_vv_data->vbi_fops.write)
return fh->dev->ext_vv_data->vbi_fops.write(file, data, count, ppos);
else
return -EINVAL;
default:
BUG();
return -EINVAL;
}
}
static const struct v4l2_file_operations video_fops =
{
.owner = THIS_MODULE,
.open = fops_open,
.release = fops_release,
.read = fops_read,
.write = fops_write,
.poll = fops_poll,
.mmap = fops_mmap,
.unlocked_ioctl = video_ioctl2,
};
static void vv_callback(struct saa7146_dev *dev, unsigned long status)
{
u32 isr = status;
DEB_INT("dev:%p, isr:0x%08x\n", dev, (u32)status);
if (0 != (isr & (MASK_27))) {
DEB_INT("irq: RPS0 (0x%08x)\n", isr);
saa7146_video_uops.irq_done(dev,isr);
}
if (0 != (isr & (MASK_28))) {
u32 mc2 = saa7146_read(dev, MC2);
if( 0 != (mc2 & MASK_15)) {
DEB_INT("irq: RPS1 vbi workaround (0x%08x)\n", isr);
wake_up(&dev->vv_data->vbi_wq);
saa7146_write(dev,MC2, MASK_31);
return;
}
DEB_INT("irq: RPS1 (0x%08x)\n", isr);
saa7146_vbi_uops.irq_done(dev,isr);
}
}
int saa7146_vv_init(struct saa7146_dev* dev, struct saa7146_ext_vv *ext_vv)
{
struct saa7146_vv *vv;
int err;
err = v4l2_device_register(&dev->pci->dev, &dev->v4l2_dev);
if (err)
return err;
vv = kzalloc(sizeof(struct saa7146_vv), GFP_KERNEL);
if (vv == NULL) {
ERR("out of memory. aborting.\n");
return -ENOMEM;
}
ext_vv->ops = saa7146_video_ioctl_ops;
ext_vv->core_ops = &saa7146_video_ioctl_ops;
DEB_EE("dev:%p\n", dev);
/* set default values for video parts of the saa7146 */
saa7146_write(dev, BCS_CTRL, 0x80400040);
/* enable video-port pins */
saa7146_write(dev, MC1, (MASK_10 | MASK_26));
/* save per-device extension data (one extension can
handle different devices that might need different
configuration data) */
dev->ext_vv_data = ext_vv;
vv->d_clipping.cpu_addr = pci_alloc_consistent(dev->pci, SAA7146_CLIPPING_MEM, &vv->d_clipping.dma_handle);
if( NULL == vv->d_clipping.cpu_addr ) {
ERR("out of memory. aborting.\n");
kfree(vv);
return -1;
}
memset(vv->d_clipping.cpu_addr, 0x0, SAA7146_CLIPPING_MEM);
saa7146_video_uops.init(dev,vv);
if (dev->ext_vv_data->capabilities & V4L2_CAP_VBI_CAPTURE)
saa7146_vbi_uops.init(dev,vv);
dev->vv_data = vv;
dev->vv_callback = &vv_callback;
return 0;
}
EXPORT_SYMBOL_GPL(saa7146_vv_init);
int saa7146_vv_release(struct saa7146_dev* dev)
{
struct saa7146_vv *vv = dev->vv_data;
DEB_EE("dev:%p\n", dev);
v4l2_device_unregister(&dev->v4l2_dev);
pci_free_consistent(dev->pci, SAA7146_CLIPPING_MEM, vv->d_clipping.cpu_addr, vv->d_clipping.dma_handle);
kfree(vv);
dev->vv_data = NULL;
dev->vv_callback = NULL;
return 0;
}
EXPORT_SYMBOL_GPL(saa7146_vv_release);
int saa7146_register_device(struct video_device **vid, struct saa7146_dev* dev,
char *name, int type)
{
struct video_device *vfd;
int err;
int i;
DEB_EE("dev:%p, name:'%s', type:%d\n", dev, name, type);
// released by vfd->release
vfd = video_device_alloc();
if (vfd == NULL)
return -ENOMEM;
vfd->fops = &video_fops;
vfd->ioctl_ops = &dev->ext_vv_data->ops;
vfd->release = video_device_release;
/* Locking in file operations other than ioctl should be done by
the driver, not the V4L2 core.
This driver needs auditing so that this flag can be removed. */
set_bit(V4L2_FL_LOCK_ALL_FOPS, &vfd->flags);
vfd->lock = &dev->v4l2_lock;
vfd->tvnorms = 0;
for (i = 0; i < dev->ext_vv_data->num_stds; i++)
vfd->tvnorms |= dev->ext_vv_data->stds[i].id;
strlcpy(vfd->name, name, sizeof(vfd->name));
video_set_drvdata(vfd, dev);
err = video_register_device(vfd, type, -1);
if (err < 0) {
ERR("cannot register v4l2 device. skipping.\n");
video_device_release(vfd);
return err;
}
pr_info("%s: registered device %s [v4l2]\n",
dev->name, video_device_node_name(vfd));
*vid = vfd;
return 0;
}
EXPORT_SYMBOL_GPL(saa7146_register_device);
int saa7146_unregister_device(struct video_device **vid, struct saa7146_dev* dev)
{
DEB_EE("dev:%p\n", dev);
video_unregister_device(*vid);
*vid = NULL;
return 0;
}
EXPORT_SYMBOL_GPL(saa7146_unregister_device);
static int __init saa7146_vv_init_module(void)
{
return 0;
}
static void __exit saa7146_vv_cleanup_module(void)
{
}
module_init(saa7146_vv_init_module);
module_exit(saa7146_vv_cleanup_module);
MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
MODULE_DESCRIPTION("video4linux driver for saa7146-based hardware");
MODULE_LICENSE("GPL");