Commit 1c3bb743 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Mauro Carvalho Chehab
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V4L/DVB (10083): soc-camera: unify locking, play nicer with videobuf locking



Move mutex from host drivers to camera device object, take into account
videobuf locking.
Signed-off-by: default avatarGuennadi Liakhovetski <lg@denx.de>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent bf507158
......@@ -25,7 +25,6 @@
#include <linux/version.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/clk.h>
#include <media/v4l2-common.h>
......@@ -164,8 +163,6 @@
CICR0_PERRM | CICR0_QDM | CICR0_CDM | CICR0_SOFM | \
CICR0_EOFM | CICR0_FOM)
static DEFINE_MUTEX(camera_lock);
/*
* Structures
*/
......@@ -813,16 +810,17 @@ static irqreturn_t pxa_camera_irq(int irq, void *data)
return IRQ_HANDLED;
}
/* The following two functions absolutely depend on the fact, that
* there can be only one camera on PXA quick capture interface */
/*
* The following two functions absolutely depend on the fact, that
* there can be only one camera on PXA quick capture interface
* Called with .video_lock held
*/
static int pxa_camera_add_device(struct soc_camera_device *icd)
{
struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
struct pxa_camera_dev *pcdev = ici->priv;
int ret;
mutex_lock(&camera_lock);
if (pcdev->icd) {
ret = -EBUSY;
goto ebusy;
......@@ -838,11 +836,10 @@ static int pxa_camera_add_device(struct soc_camera_device *icd)
pcdev->icd = icd;
ebusy:
mutex_unlock(&camera_lock);
return ret;
}
/* Called with .video_lock held */
static void pxa_camera_remove_device(struct soc_camera_device *icd)
{
struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
......
......@@ -29,7 +29,6 @@
#include <linux/version.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/videodev2.h>
#include <linux/clk.h>
......@@ -75,8 +74,6 @@
#define CDBYR2 0x98 /* Capture data bottom-field address Y register 2 */
#define CDBCR2 0x9c /* Capture data bottom-field address C register 2 */
static DEFINE_MUTEX(camera_lock);
/* per video frame buffer */
struct sh_mobile_ceu_buffer {
struct videobuf_buffer vb; /* v4l buffer must be first */
......@@ -292,14 +289,13 @@ static irqreturn_t sh_mobile_ceu_irq(int irq, void *data)
return IRQ_HANDLED;
}
/* Called with .video_lock held */
static int sh_mobile_ceu_add_device(struct soc_camera_device *icd)
{
struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
struct sh_mobile_ceu_dev *pcdev = ici->priv;
int ret = -EBUSY;
mutex_lock(&camera_lock);
if (pcdev->icd)
goto err;
......@@ -319,11 +315,10 @@ static int sh_mobile_ceu_add_device(struct soc_camera_device *icd)
pcdev->icd = icd;
err:
mutex_unlock(&camera_lock);
return ret;
}
/* Called with .video_lock held */
static void sh_mobile_ceu_remove_device(struct soc_camera_device *icd)
{
struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
......
......@@ -33,7 +33,6 @@
static LIST_HEAD(hosts);
static LIST_HEAD(devices);
static DEFINE_MUTEX(list_lock);
static DEFINE_MUTEX(video_lock);
const struct soc_camera_data_format *soc_camera_format_by_fourcc(
struct soc_camera_device *icd, unsigned int fourcc)
......@@ -270,8 +269,10 @@ static int soc_camera_open(struct inode *inode, struct file *file)
if (!icf)
return -ENOMEM;
/* Protect against icd->remove() until we module_get() both drivers. */
mutex_lock(&video_lock);
/*
* It is safe to dereference these pointers now as long as a user has
* the video device open - we are protected by the held cdev reference.
*/
vdev = video_devdata(file);
icd = container_of(vdev->parent, struct soc_camera_device, dev);
......@@ -289,6 +290,9 @@ static int soc_camera_open(struct inode *inode, struct file *file)
goto emgi;
}
/* Protect against icd->remove() until we module_get() both drivers. */
mutex_lock(&icd->video_lock);
icf->icd = icd;
icd->use_count++;
......@@ -304,7 +308,7 @@ static int soc_camera_open(struct inode *inode, struct file *file)
}
}
mutex_unlock(&video_lock);
mutex_unlock(&icd->video_lock);
file->private_data = icf;
dev_dbg(&icd->dev, "camera device open\n");
......@@ -313,16 +317,16 @@ static int soc_camera_open(struct inode *inode, struct file *file)
return 0;
/* All errors are entered with the video_lock held */
/* First two errors are entered with the .video_lock held */
eiciadd:
soc_camera_free_user_formats(icd);
eiufmt:
icd->use_count--;
mutex_unlock(&icd->video_lock);
module_put(ici->ops->owner);
emgi:
module_put(icd->ops->owner);
emgd:
mutex_unlock(&video_lock);
vfree(icf);
return ret;
}
......@@ -334,15 +338,16 @@ static int soc_camera_close(struct inode *inode, struct file *file)
struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
struct video_device *vdev = icd->vdev;
mutex_lock(&video_lock);
mutex_lock(&icd->video_lock);
icd->use_count--;
if (!icd->use_count) {
ici->ops->remove(icd);
soc_camera_free_user_formats(icd);
}
mutex_unlock(&icd->video_lock);
module_put(icd->ops->owner);
module_put(ici->ops->owner);
mutex_unlock(&video_lock);
vfree(icf);
......@@ -424,18 +429,27 @@ static int soc_camera_s_fmt_vid_cap(struct file *file, void *priv,
if (ret < 0)
return ret;
mutex_lock(&icf->vb_vidq.vb_lock);
if (videobuf_queue_is_busy(&icf->vb_vidq)) {
dev_err(&icd->dev, "S_FMT denied: queue busy\n");
ret = -EBUSY;
goto unlock;
}
rect.left = icd->x_current;
rect.top = icd->y_current;
rect.width = pix->width;
rect.height = pix->height;
ret = ici->ops->set_fmt(icd, pix->pixelformat, &rect);
if (ret < 0) {
return ret;
goto unlock;
} else if (!icd->current_fmt ||
icd->current_fmt->fourcc != pixfmt) {
dev_err(&ici->dev,
"Host driver hasn't set up current format correctly!\n");
return -EINVAL;
ret = -EINVAL;
goto unlock;
}
icd->width = rect.width;
......@@ -449,7 +463,12 @@ static int soc_camera_s_fmt_vid_cap(struct file *file, void *priv,
icd->width, icd->height);
/* set physical bus parameters */
return ici->ops->set_bus_param(icd, pixfmt);
ret = ici->ops->set_bus_param(icd, pixfmt);
unlock:
mutex_unlock(&icf->vb_vidq.vb_lock);
return ret;
}
static int soc_camera_enum_fmt_vid_cap(struct file *file, void *priv,
......@@ -510,6 +529,7 @@ static int soc_camera_streamon(struct file *file, void *priv,
{
struct soc_camera_file *icf = file->private_data;
struct soc_camera_device *icd = icf->icd;
int ret;
WARN_ON(priv != file->private_data);
......@@ -518,10 +538,16 @@ static int soc_camera_streamon(struct file *file, void *priv,
if (i != V4L2_BUF_TYPE_VIDEO_CAPTURE)
return -EINVAL;
mutex_lock(&icd->video_lock);
icd->ops->start_capture(icd);
/* This calls buf_queue from host driver's videobuf_queue_ops */
return videobuf_streamon(&icf->vb_vidq);
ret = videobuf_streamon(&icf->vb_vidq);
mutex_unlock(&icd->video_lock);
return ret;
}
static int soc_camera_streamoff(struct file *file, void *priv,
......@@ -537,12 +563,16 @@ static int soc_camera_streamoff(struct file *file, void *priv,
if (i != V4L2_BUF_TYPE_VIDEO_CAPTURE)
return -EINVAL;
mutex_lock(&icd->video_lock);
/* This calls buf_release from host driver's videobuf_queue_ops for all
* remaining buffers. When the last buffer is freed, stop capture */
videobuf_streamoff(&icf->vb_vidq);
icd->ops->stop_capture(icd);
mutex_unlock(&icd->video_lock);
return 0;
}
......@@ -654,6 +684,9 @@ static int soc_camera_s_crop(struct file *file, void *fh,
if (a->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
return -EINVAL;
/* Cropping is allowed during a running capture, guard consistency */
mutex_lock(&icf->vb_vidq.vb_lock);
ret = ici->ops->set_fmt(icd, 0, &a->c);
if (!ret) {
icd->width = a->c.width;
......@@ -662,6 +695,8 @@ static int soc_camera_s_crop(struct file *file, void *fh,
icd->y_current = a->c.top;
}
mutex_unlock(&icf->vb_vidq.vb_lock);
return ret;
}
......@@ -775,11 +810,32 @@ static int soc_camera_probe(struct device *dev)
struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
int ret;
/*
* Possible race scenario:
* modprobe <camera-host-driver> triggers __func__
* at this moment respective <camera-sensor-driver> gets rmmod'ed
* to protect take module references.
*/
if (!try_module_get(icd->ops->owner)) {
dev_err(&icd->dev, "Couldn't lock sensor driver.\n");
ret = -EINVAL;
goto emgd;
}
if (!try_module_get(ici->ops->owner)) {
dev_err(&icd->dev, "Couldn't lock capture bus driver.\n");
ret = -EINVAL;
goto emgi;
}
mutex_lock(&icd->video_lock);
/* We only call ->add() here to activate and probe the camera.
* We shall ->remove() and deactivate it immediately afterwards. */
ret = ici->ops->add(icd);
if (ret < 0)
return ret;
goto eiadd;
ret = icd->ops->probe(icd);
if (ret >= 0) {
......@@ -793,6 +849,12 @@ static int soc_camera_probe(struct device *dev)
}
ici->ops->remove(icd);
eiadd:
mutex_unlock(&icd->video_lock);
module_put(ici->ops->owner);
emgi:
module_put(icd->ops->owner);
emgd:
return ret;
}
......@@ -966,6 +1028,7 @@ int soc_camera_device_register(struct soc_camera_device *icd)
icd->dev.release = dummy_release;
icd->use_count = 0;
icd->host_priv = NULL;
mutex_init(&icd->video_lock);
return scan_add_device(icd);
}
......@@ -1012,6 +1075,10 @@ static const struct v4l2_ioctl_ops soc_camera_ioctl_ops = {
#endif
};
/*
* Usually called from the struct soc_camera_ops .probe() method, i.e., from
* soc_camera_probe() above with .video_lock held
*/
int soc_camera_video_start(struct soc_camera_device *icd)
{
struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
......@@ -1027,7 +1094,7 @@ int soc_camera_video_start(struct soc_camera_device *icd)
dev_dbg(&ici->dev, "Allocated video_device %p\n", vdev);
strlcpy(vdev->name, ici->drv_name, sizeof(vdev->name));
/* Maybe better &ici->dev */
vdev->parent = &icd->dev;
vdev->current_norm = V4L2_STD_UNKNOWN;
vdev->fops = &soc_camera_fops;
......@@ -1061,10 +1128,10 @@ void soc_camera_video_stop(struct soc_camera_device *icd)
if (!icd->dev.parent || !vdev)
return;
mutex_lock(&video_lock);
mutex_lock(&icd->video_lock);
video_unregister_device(vdev);
icd->vdev = NULL;
mutex_unlock(&video_lock);
mutex_unlock(&icd->video_lock);
}
EXPORT_SYMBOL(soc_camera_video_stop);
......
......@@ -12,9 +12,10 @@
#ifndef SOC_CAMERA_H
#define SOC_CAMERA_H
#include <linux/mutex.h>
#include <linux/pm.h>
#include <linux/videodev2.h>
#include <media/videobuf-core.h>
#include <linux/pm.h>
struct soc_camera_device {
struct list_head list;
......@@ -45,9 +46,10 @@ struct soc_camera_device {
struct soc_camera_format_xlate *user_formats;
int num_user_formats;
struct module *owner;
void *host_priv; /* per-device host private data */
/* soc_camera.c private count. Only accessed with video_lock held */
void *host_priv; /* Per-device host private data */
/* soc_camera.c private count. Only accessed with .video_lock held */
int use_count;
struct mutex video_lock; /* Protects device data */
};
struct soc_camera_file {
......
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