From 9511f472cfb47c53ad0f210dd137dedfb753cea7 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Sat, 14 Feb 2009 15:54:23 +0100 Subject: v4l2-device: allow a NULL parent device when registering. From: Hans Verkuil Some drivers (e.g. for ISA devices) have no parent device because there is no associated bus driver. Allow the parent device to be NULL in those cases when registering v4l2_device. Priority: normal Signed-off-by: Hans Verkuil --- linux/Documentation/video4linux/v4l2-framework.txt | 58 +++++++++++----------- linux/drivers/media/video/v4l2-device.c | 37 +++++++++----- linux/include/media/v4l2-device.h | 31 +++++++----- 3 files changed, 72 insertions(+), 54 deletions(-) (limited to 'linux') diff --git a/linux/Documentation/video4linux/v4l2-framework.txt b/linux/Documentation/video4linux/v4l2-framework.txt index a6005257a..e1620e2a3 100644 --- a/linux/Documentation/video4linux/v4l2-framework.txt +++ b/linux/Documentation/video4linux/v4l2-framework.txt @@ -84,12 +84,14 @@ You must register the device instance: v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev); Registration will initialize the v4l2_device struct and link dev->driver_data -to v4l2_dev. Registration will also set v4l2_dev->name to a value derived from -dev (driver name followed by the bus_id, to be precise). You may change the -name after registration if you want. +to v4l2_dev. If v4l2_dev->name is empty then it will be set to a value derived +from dev (driver name followed by the bus_id, to be precise). If you set it +up before calling v4l2_device_register then it will be untouched. If dev is +NULL, then you *must* setup v4l2_dev->name before calling v4l2_device_register. The first 'dev' argument is normally the struct device pointer of a pci_dev, -usb_device or platform_device. +usb_device or platform_device. It is rare for dev to be NULL, but it happens +with ISA devices, for example. You unregister with: @@ -531,11 +533,11 @@ struct v4l2_device *v4l2_dev = vdev->v4l2_dev; video buffer helper functions ----------------------------- -The v4l2 core API provides a standard method for dealing with video -buffers. Those methods allow a driver to implement read(), mmap() and +The v4l2 core API provides a standard method for dealing with video +buffers. Those methods allow a driver to implement read(), mmap() and overlay() on a consistent way. -There are currently methods for using video buffers on devices that +There are currently methods for using video buffers on devices that supports DMA with scatter/gather method (videobuf-dma-sg), DMA with linear access (videobuf-dma-contig), and vmalloced buffers, mostly used on USB drivers (videobuf-vmalloc). @@ -544,50 +546,50 @@ Any driver using videobuf should provide operations (callbacks) for four handlers: ops->buf_setup - calculates the size of the video buffers and avoid they - to waste more than some maximum limit of RAM; + to waste more than some maximum limit of RAM; ops->buf_prepare - fills the video buffer structs and calls videobuf_iolock() to alloc and prepare mmaped memory; ops->buf_queue - advices the driver that another buffer were - requested (by read() or by QBUF); + requested (by read() or by QBUF); ops->buf_release - frees any buffer that were allocated. In order to use it, the driver need to have a code (generally called at interrupt context) that will properly handle the buffer request lists, announcing that a new buffer were filled. -The irq handling code should handle the videobuf task lists, in order -to advice videobuf that a new frame were filled, in order to honor to a +The irq handling code should handle the videobuf task lists, in order +to advice videobuf that a new frame were filled, in order to honor to a request. The code is generally like this one: - if (list_empty(&dma_q->active)) + if (list_empty(&dma_q->active)) return; - buf = list_entry(dma_q->active.next, struct vbuffer, vb.queue); + buf = list_entry(dma_q->active.next, struct vbuffer, vb.queue); - if (!waitqueue_active(&buf->vb.done)) + if (!waitqueue_active(&buf->vb.done)) return; /* Some logic to handle the buf may be needed here */ - list_del(&buf->vb.queue); - do_gettimeofday(&buf->vb.ts); - wake_up(&buf->vb.done); + list_del(&buf->vb.queue); + do_gettimeofday(&buf->vb.ts); + wake_up(&buf->vb.done); -Those are the videobuffer functions used on drivers, implemented on +Those are the videobuffer functions used on drivers, implemented on videobuf-core: - Videobuf init functions videobuf_queue_sg_init() - Initializes the videobuf infrastructure. This function should be - called before any other videobuf function on drivers that uses DMA + Initializes the videobuf infrastructure. This function should be + called before any other videobuf function on drivers that uses DMA Scatter/Gather buffers. videobuf_queue_dma_contig_init - Initializes the videobuf infrastructure. This function should be - called before any other videobuf function on drivers that need DMA + Initializes the videobuf infrastructure. This function should be + called before any other videobuf function on drivers that need DMA contiguous buffers. videobuf_queue_vmalloc_init() - Initializes the videobuf infrastructure. This function should be + Initializes the videobuf infrastructure. This function should be called before any other videobuf function on USB (and other drivers) that need a vmalloced type of videobuf. @@ -607,12 +609,12 @@ videobuf-core: Stops video handling, ends mmap and frees mmap and other buffers. - V4L2 api functions. Those functions correspond to VIDIOC_foo ioctls: - videobuf_reqbufs(), videobuf_querybuf(), videobuf_qbuf(), + videobuf_reqbufs(), videobuf_querybuf(), videobuf_qbuf(), videobuf_dqbuf(), videobuf_streamon(), videobuf_streamoff(). - V4L1 api function (corresponds to VIDIOCMBUF ioctl): videobuf_cgmbuf() - This function is used to provide backward compatibility with V4L1 + This function is used to provide backward compatibility with V4L1 API. - Some help functions for read()/poll() operations: @@ -623,7 +625,7 @@ videobuf-core: videobuf_poll_stream() polling help function -The better way to understand it is to take a look at vivi driver. One -of the main reasons for vivi is to be a videobuf usage example. the -vivi_thread_tick() does the task that the IRQ callback would do on PCI +The better way to understand it is to take a look at vivi driver. One +of the main reasons for vivi is to be a videobuf usage example. the +vivi_thread_tick() does the task that the IRQ callback would do on PCI drivers (or the irq callback on USB). diff --git a/linux/drivers/media/video/v4l2-device.c b/linux/drivers/media/video/v4l2-device.c index e84925976..cb8234437 100644 --- a/linux/drivers/media/video/v4l2-device.c +++ b/linux/drivers/media/video/v4l2-device.c @@ -27,15 +27,24 @@ int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev) { - if (dev == NULL || v4l2_dev == NULL) + if (v4l2_dev == NULL) return -EINVAL; - /* Warn if we apparently re-register a device */ - WARN_ON(dev_get_drvdata(dev) != NULL); + INIT_LIST_HEAD(&v4l2_dev->subdevs); spin_lock_init(&v4l2_dev->lock); v4l2_dev->dev = dev; - snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s", + if (dev == NULL) { + /* If dev == NULL, then name must be filled in by the caller */ + WARN_ON(!v4l2_dev->name[0]); + return 0; + } + + /* Set name to driver name + device name if it is empty. */ + if (!v4l2_dev->name[0]) + snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s", dev->driver->name, dev_name(dev)); + if (dev_get_drvdata(dev)) + v4l2_warn(v4l2_dev, "Non-NULL drvdata on register\n"); dev_set_drvdata(dev, v4l2_dev); return 0; } @@ -45,10 +54,11 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev) { struct v4l2_subdev *sd, *next; - if (v4l2_dev == NULL || v4l2_dev->dev == NULL) + if (v4l2_dev == NULL) return; - dev_set_drvdata(v4l2_dev->dev, NULL); - /* unregister subdevs */ + if (v4l2_dev->dev) + dev_set_drvdata(v4l2_dev->dev, NULL); + /* Unregister subdevs */ list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) v4l2_device_unregister_subdev(sd); @@ -56,19 +66,20 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev) } EXPORT_SYMBOL_GPL(v4l2_device_unregister); -int v4l2_device_register_subdev(struct v4l2_device *dev, struct v4l2_subdev *sd) +int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev, + struct v4l2_subdev *sd) { /* Check for valid input */ - if (dev == NULL || sd == NULL || !sd->name[0]) + if (v4l2_dev == NULL || sd == NULL || !sd->name[0]) return -EINVAL; /* Warn if we apparently re-register a subdev */ WARN_ON(sd->dev != NULL); if (!try_module_get(sd->owner)) return -ENODEV; - sd->dev = dev; - spin_lock(&dev->lock); - list_add_tail(&sd->list, &dev->subdevs); - spin_unlock(&dev->lock); + sd->dev = v4l2_dev; + spin_lock(&v4l2_dev->lock); + list_add_tail(&sd->list, &v4l2_dev->subdevs); + spin_unlock(&v4l2_dev->lock); return 0; } EXPORT_SYMBOL_GPL(v4l2_device_register_subdev); diff --git a/linux/include/media/v4l2-device.h b/linux/include/media/v4l2-device.h index 55e41afd9..5d7146dc2 100644 --- a/linux/include/media/v4l2-device.h +++ b/linux/include/media/v4l2-device.h @@ -33,7 +33,9 @@ #define V4L2_DEVICE_NAME_SIZE (BUS_ID_SIZE + 16) struct v4l2_device { - /* dev->driver_data points to this struct */ + /* dev->driver_data points to this struct. + Note: dev might be NULL if there is no parent device + as is the case with e.g. ISA devices. */ struct device *dev; /* used to keep track of the registered subdevs */ struct list_head subdevs; @@ -44,7 +46,9 @@ struct v4l2_device { char name[V4L2_DEVICE_NAME_SIZE]; }; -/* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev */ +/* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev. + dev may be NULL in rare cases (ISA devices). In that case you + must fill in the v4l2_dev->name field before calling this function. */ int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev); /* Set v4l2_dev->dev->driver_data to NULL and unregister all sub-devices */ void v4l2_device_unregister(struct v4l2_device *v4l2_dev); @@ -52,23 +56,24 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev); /* Register a subdev with a v4l2 device. While registered the subdev module is marked as in-use. An error is returned if the module is no longer loaded when you attempt to register it. */ -int __must_check v4l2_device_register_subdev(struct v4l2_device *dev, struct v4l2_subdev *sd); +int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev, + struct v4l2_subdev *sd); /* Unregister a subdev with a v4l2 device. Can also be called if the subdev wasn't registered. In that case it will do nothing. */ void v4l2_device_unregister_subdev(struct v4l2_subdev *sd); /* Iterate over all subdevs. */ -#define v4l2_device_for_each_subdev(sd, dev) \ - list_for_each_entry(sd, &(dev)->subdevs, list) +#define v4l2_device_for_each_subdev(sd, v4l2_dev) \ + list_for_each_entry(sd, &(v4l2_dev)->subdevs, list) /* Call the specified callback for all subdevs matching the condition. Ignore any errors. Note that you cannot add or delete a subdev while walking the subdevs list. */ -#define __v4l2_device_call_subdevs(dev, cond, o, f, args...) \ +#define __v4l2_device_call_subdevs(v4l2_dev, cond, o, f, args...) \ do { \ struct v4l2_subdev *sd; \ \ - list_for_each_entry(sd, &(dev)->subdevs, list) \ + list_for_each_entry(sd, &(v4l2_dev)->subdevs, list) \ if ((cond) && sd->ops->o && sd->ops->o->f) \ sd->ops->o->f(sd , ##args); \ } while (0) @@ -77,12 +82,12 @@ void v4l2_device_unregister_subdev(struct v4l2_subdev *sd); If the callback returns an error other than 0 or -ENOIOCTLCMD, then return with that error code. Note that you cannot add or delete a subdev while walking the subdevs list. */ -#define __v4l2_device_call_subdevs_until_err(dev, cond, o, f, args...) \ +#define __v4l2_device_call_subdevs_until_err(v4l2_dev, cond, o, f, args...) \ ({ \ struct v4l2_subdev *sd; \ long err = 0; \ \ - list_for_each_entry(sd, &(dev)->subdevs, list) { \ + list_for_each_entry(sd, &(v4l2_dev)->subdevs, list) { \ if ((cond) && sd->ops->o && sd->ops->o->f) \ err = sd->ops->o->f(sd , ##args); \ if (err && err != -ENOIOCTLCMD) \ @@ -94,16 +99,16 @@ void v4l2_device_unregister_subdev(struct v4l2_subdev *sd); /* Call the specified callback for all subdevs matching grp_id (if 0, then match them all). Ignore any errors. Note that you cannot add or delete a subdev while walking the subdevs list. */ -#define v4l2_device_call_all(dev, grpid, o, f, args...) \ - __v4l2_device_call_subdevs(dev, \ +#define v4l2_device_call_all(v4l2_dev, grpid, o, f, args...) \ + __v4l2_device_call_subdevs(v4l2_dev, \ !(grpid) || sd->grp_id == (grpid), o, f , ##args) /* Call the specified callback for all subdevs matching grp_id (if 0, then match them all). If the callback returns an error other than 0 or -ENOIOCTLCMD, then return with that error code. Note that you cannot add or delete a subdev while walking the subdevs list. */ -#define v4l2_device_call_until_err(dev, grpid, o, f, args...) \ - __v4l2_device_call_subdevs_until_err(dev, \ +#define v4l2_device_call_until_err(v4l2_dev, grpid, o, f, args...) \ + __v4l2_device_call_subdevs_until_err(v4l2_dev, \ !(grpid) || sd->grp_id == (grpid), o, f , ##args) #endif -- cgit v1.2.3