From 7ae0cd9bc793e16d8d68df3c17c601732cc1d3c7 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Fri, 19 Jun 2009 11:32:56 -0300 Subject: V4L/DVB (12541): v4l: remove video_register_device_index video_register_device_index is never actually called, instead the stream index number is always calculated automatically. This patch removes this function and simplifies the internal get_index function since that can now always just return the first free index. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/v4l2-dev.c | 55 ++++++++++++------------------------------ 1 file changed, 15 insertions(+), 40 deletions(-) (limited to 'drivers/media/video/v4l2-dev.c') diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c index a7f1b69a7dab..1219721894a1 100644 --- a/drivers/media/video/v4l2-dev.c +++ b/drivers/media/video/v4l2-dev.c @@ -299,32 +299,28 @@ static const struct file_operations v4l2_fops = { }; /** - * get_index - assign stream number based on parent device + * get_index - assign stream index number based on parent device * @vdev: video_device to assign index number to, vdev->parent should be assigned - * @num: -1 if auto assign, requested number otherwise * * Note that when this is called the new device has not yet been registered - * in the video_device array. + * in the video_device array, but it was able to obtain a minor number. * - * Returns -ENFILE if num is already in use, a free index number if - * successful. + * This means that we can always obtain a free stream index number since + * the worst case scenario is that there are VIDEO_NUM_DEVICES - 1 slots in + * use of the video_device array. + * + * Returns a free index number. */ -static int get_index(struct video_device *vdev, int num) +static int get_index(struct video_device *vdev) { /* This can be static since this function is called with the global videodev_lock held. */ static DECLARE_BITMAP(used, VIDEO_NUM_DEVICES); int i; - if (num >= VIDEO_NUM_DEVICES) { - printk(KERN_ERR "videodev: %s num is too large\n", __func__); - return -EINVAL; - } - - /* Some drivers do not set the parent. In that case always return - num or 0. */ + /* Some drivers do not set the parent. In that case always return 0. */ if (vdev->parent == NULL) - return num >= 0 ? num : 0; + return 0; bitmap_zero(used, VIDEO_NUM_DEVICES); @@ -335,30 +331,15 @@ static int get_index(struct video_device *vdev, int num) } } - if (num >= 0) { - if (test_bit(num, used)) - return -ENFILE; - return num; - } - - i = find_first_zero_bit(used, VIDEO_NUM_DEVICES); - return i == VIDEO_NUM_DEVICES ? -ENFILE : i; + return find_first_zero_bit(used, VIDEO_NUM_DEVICES); } -int video_register_device(struct video_device *vdev, int type, int nr) -{ - return video_register_device_index(vdev, type, nr, -1); -} -EXPORT_SYMBOL(video_register_device); - /** - * video_register_device_index - register video4linux devices + * video_register_device - register video4linux devices * @vdev: video device structure we want to register * @type: type of device to register * @nr: which device number (0 == /dev/video0, 1 == /dev/video1, ... * -1 == first free) - * @index: stream number based on parent device; - * -1 if auto assign, requested number otherwise * * The registration code assigns minor numbers based on the type * requested. -ENFILE is returned in all the device slots for this @@ -377,8 +358,7 @@ EXPORT_SYMBOL(video_register_device); * * %VFL_TYPE_RADIO - A radio card */ -int video_register_device_index(struct video_device *vdev, int type, int nr, - int index) +int video_register_device(struct video_device *vdev, int type, int nr) { int i = 0; int ret; @@ -481,14 +461,9 @@ int video_register_device_index(struct video_device *vdev, int type, int nr, set_bit(nr, video_nums[type]); /* Should not happen since we thought this minor was free */ WARN_ON(video_device[vdev->minor] != NULL); - ret = vdev->index = get_index(vdev, index); + vdev->index = get_index(vdev); mutex_unlock(&videodev_lock); - if (ret < 0) { - printk(KERN_ERR "%s: get_index failed\n", __func__); - goto cleanup; - } - /* Part 3: Initialize the character device */ vdev->cdev = cdev_alloc(); if (vdev->cdev == NULL) { @@ -543,7 +518,7 @@ cleanup: vdev->minor = -1; return ret; } -EXPORT_SYMBOL(video_register_device_index); +EXPORT_SYMBOL(video_register_device); /** * video_unregister_device - unregister a video4linux device -- cgit v1.2.3 From 22e221258b56cc1a4dc5a9fb2c26f4d6ed9dde81 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Sun, 6 Sep 2009 07:13:14 -0300 Subject: V4L/DVB (12722): v4l2-dev: replace 'kernel number' by 'device node number'. The term 'kernel number' is very vague, so replace it with the somewhat more descriptive term 'device node number'. In one place the local variable 'nr' was used to create the device node number of the new device name. This has been replaced with the vdev->num field to more clearly mark this as being the device node number and not the minor number. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/video4linux/v4l2-framework.txt | 8 +++--- drivers/media/video/v4l2-dev.c | 38 +++++++++++++++------------- 2 files changed, 24 insertions(+), 22 deletions(-) (limited to 'drivers/media/video/v4l2-dev.c') diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt index cb6c7eb51472..38b3716d8643 100644 --- a/Documentation/video4linux/v4l2-framework.txt +++ b/Documentation/video4linux/v4l2-framework.txt @@ -486,14 +486,14 @@ VFL_TYPE_RADIO: radioX for radio tuners VFL_TYPE_VTX: vtxX for teletext devices (deprecated, don't use) The last argument gives you a certain amount of control over the device -kernel number used (i.e. the X in videoX). Normally you will pass -1 to +device node number used (i.e. the X in videoX). Normally you will pass -1 to let the v4l2 framework pick the first free number. But if a driver creates many devices, then it can be useful to have different video devices in separate ranges. For example, video capture devices start at 0, video output devices start at 16. -So you can use the last argument to specify a minimum kernel number and -the v4l2 framework will try to pick the first free number that is equal +So you can use the last argument to specify a minimum device node number +and the v4l2 framework will try to pick the first free number that is equal or higher to what you passed. If that fails, then it will just pick the first free number. @@ -513,7 +513,7 @@ After the device was successfully registered, then you can use these fields: - vfl_type: the device type passed to video_register_device. - minor: the assigned device minor number. -- num: the device kernel number (i.e. the X in videoX). +- num: the device node number (i.e. the X in videoX). - index: the device index number. If the registration failed, then you need to call video_device_release() diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c index 1219721894a1..4e61c77b7634 100644 --- a/drivers/media/video/v4l2-dev.c +++ b/drivers/media/video/v4l2-dev.c @@ -66,7 +66,7 @@ static struct device_attribute video_device_attrs[] = { */ static struct video_device *video_device[VIDEO_NUM_DEVICES]; static DEFINE_MUTEX(videodev_lock); -static DECLARE_BITMAP(video_nums[VFL_TYPE_MAX], VIDEO_NUM_DEVICES); +static DECLARE_BITMAP(devnode_nums[VFL_TYPE_MAX], VIDEO_NUM_DEVICES); struct video_device *video_device_alloc(void) { @@ -119,8 +119,8 @@ static void v4l2_device_release(struct device *cd) the release() callback. */ vdev->cdev = NULL; - /* Mark minor as free */ - clear_bit(vdev->num, video_nums[vdev->vfl_type]); + /* Mark device node number as free */ + clear_bit(vdev->num, devnode_nums[vdev->vfl_type]); mutex_unlock(&videodev_lock); @@ -338,13 +338,14 @@ static int get_index(struct video_device *vdev) * video_register_device - register video4linux devices * @vdev: video device structure we want to register * @type: type of device to register - * @nr: which device number (0 == /dev/video0, 1 == /dev/video1, ... + * @nr: which device node number (0 == /dev/video0, 1 == /dev/video1, ... * -1 == first free) * - * The registration code assigns minor numbers based on the type - * requested. -ENFILE is returned in all the device slots for this - * category are full. If not then the minor field is set and the - * driver initialize function is called (if non %NULL). + * The registration code assigns minor numbers and device node numbers + * based on the requested type and registers the new device node with + * the kernel. + * An error is returned if no free minor or device node number could be + * found, or if the registration of the device node failed. * * Zero is returned on success. * @@ -401,7 +402,7 @@ int video_register_device(struct video_device *vdev, int type, int nr) if (vdev->v4l2_dev && vdev->v4l2_dev->dev) vdev->parent = vdev->v4l2_dev->dev; - /* Part 2: find a free minor, kernel number and device index. */ + /* Part 2: find a free minor, device node number and device index. */ #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES /* Keep the ranges for the first four types for historical * reasons. @@ -432,21 +433,22 @@ int video_register_device(struct video_device *vdev, int type, int nr) } #endif - /* Pick a minor number */ + /* Pick a device node number */ mutex_lock(&videodev_lock); - nr = find_next_zero_bit(video_nums[type], minor_cnt, nr == -1 ? 0 : nr); + nr = find_next_zero_bit(devnode_nums[type], minor_cnt, nr == -1 ? 0 : nr); if (nr == minor_cnt) - nr = find_first_zero_bit(video_nums[type], minor_cnt); + nr = find_first_zero_bit(devnode_nums[type], minor_cnt); if (nr == minor_cnt) { - printk(KERN_ERR "could not get a free kernel number\n"); + printk(KERN_ERR "could not get a free device node number\n"); mutex_unlock(&videodev_lock); return -ENFILE; } #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES - /* 1-on-1 mapping of kernel number to minor number */ + /* 1-on-1 mapping of device node number to minor number */ i = nr; #else - /* The kernel number and minor numbers are independent */ + /* The device node number and minor numbers are independent, so + we just find the first free minor number. */ for (i = 0; i < VIDEO_NUM_DEVICES; i++) if (video_device[i] == NULL) break; @@ -458,7 +460,7 @@ int video_register_device(struct video_device *vdev, int type, int nr) #endif vdev->minor = i + minor_offset; vdev->num = nr; - set_bit(nr, video_nums[type]); + set_bit(nr, devnode_nums[type]); /* Should not happen since we thought this minor was free */ WARN_ON(video_device[vdev->minor] != NULL); vdev->index = get_index(vdev); @@ -492,7 +494,7 @@ int video_register_device(struct video_device *vdev, int type, int nr) vdev->dev.devt = MKDEV(VIDEO_MAJOR, vdev->minor); if (vdev->parent) vdev->dev.parent = vdev->parent; - dev_set_name(&vdev->dev, "%s%d", name_base, nr); + dev_set_name(&vdev->dev, "%s%d", name_base, vdev->num); ret = device_register(&vdev->dev); if (ret < 0) { printk(KERN_ERR "%s: device_register failed\n", __func__); @@ -512,7 +514,7 @@ cleanup: mutex_lock(&videodev_lock); if (vdev->cdev) cdev_del(vdev->cdev); - clear_bit(vdev->num, video_nums[type]); + clear_bit(vdev->num, devnode_nums[type]); mutex_unlock(&videodev_lock); /* Mark this video device as never having been registered. */ vdev->minor = -1; -- cgit v1.2.3 From 5062cb70c828bd7b2a8223390ae836c5baa250b9 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Mon, 7 Sep 2009 03:40:24 -0300 Subject: V4L/DVB (12724): v4l2-dev: add simple wrapper functions around the devnode numbers There are some subtle differences in the way the devnode numbers are handled depending on whether the FIXED_MINOR_RANGES config option is set. Add some simple wrapper functions to handle that correctly. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/v4l2-dev.c | 53 ++++++++++++++++++++++++++++++++++++++---- 1 file changed, 48 insertions(+), 5 deletions(-) (limited to 'drivers/media/video/v4l2-dev.c') diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c index 4e61c77b7634..4715f08157bc 100644 --- a/drivers/media/video/v4l2-dev.c +++ b/drivers/media/video/v4l2-dev.c @@ -68,6 +68,48 @@ static struct video_device *video_device[VIDEO_NUM_DEVICES]; static DEFINE_MUTEX(videodev_lock); static DECLARE_BITMAP(devnode_nums[VFL_TYPE_MAX], VIDEO_NUM_DEVICES); +/* Device node utility functions */ + +/* Note: these utility functions all assume that vfl_type is in the range + [0, VFL_TYPE_MAX-1]. */ + +#ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES +/* Return the bitmap corresponding to vfl_type. */ +static inline unsigned long *devnode_bits(int vfl_type) +{ + /* Any types not assigned to fixed minor ranges must be mapped to + one single bitmap for the purposes of finding a free node number + since all those unassigned types use the same minor range. */ + int idx = (vfl_type > VFL_TYPE_VTX) ? VFL_TYPE_MAX - 1 : vfl_type; + + return devnode_nums[idx]; +} +#else +/* Return the bitmap corresponding to vfl_type. */ +static inline unsigned long *devnode_bits(int vfl_type) +{ + return devnode_nums[vfl_type]; +} +#endif + +/* Mark device node number vdev->num as used */ +static inline void devnode_set(struct video_device *vdev) +{ + set_bit(vdev->num, devnode_bits(vdev->vfl_type)); +} + +/* Mark device node number vdev->num as unused */ +static inline void devnode_clear(struct video_device *vdev) +{ + clear_bit(vdev->num, devnode_bits(vdev->vfl_type)); +} + +/* Try to find a free device node number in the range [from, to> */ +static inline int devnode_find(struct video_device *vdev, int from, int to) +{ + return find_next_zero_bit(devnode_bits(vdev->vfl_type), to, from); +} + struct video_device *video_device_alloc(void) { return kzalloc(sizeof(struct video_device), GFP_KERNEL); @@ -120,7 +162,7 @@ static void v4l2_device_release(struct device *cd) vdev->cdev = NULL; /* Mark device node number as free */ - clear_bit(vdev->num, devnode_nums[vdev->vfl_type]); + devnode_clear(vdev); mutex_unlock(&videodev_lock); @@ -435,9 +477,9 @@ int video_register_device(struct video_device *vdev, int type, int nr) /* Pick a device node number */ mutex_lock(&videodev_lock); - nr = find_next_zero_bit(devnode_nums[type], minor_cnt, nr == -1 ? 0 : nr); + nr = devnode_find(vdev, nr == -1 ? 0 : nr, minor_cnt); if (nr == minor_cnt) - nr = find_first_zero_bit(devnode_nums[type], minor_cnt); + nr = devnode_find(vdev, 0, minor_cnt); if (nr == minor_cnt) { printk(KERN_ERR "could not get a free device node number\n"); mutex_unlock(&videodev_lock); @@ -460,7 +502,8 @@ int video_register_device(struct video_device *vdev, int type, int nr) #endif vdev->minor = i + minor_offset; vdev->num = nr; - set_bit(nr, devnode_nums[type]); + devnode_set(vdev); + /* Should not happen since we thought this minor was free */ WARN_ON(video_device[vdev->minor] != NULL); vdev->index = get_index(vdev); @@ -514,7 +557,7 @@ cleanup: mutex_lock(&videodev_lock); if (vdev->cdev) cdev_del(vdev->cdev); - clear_bit(vdev->num, devnode_nums[type]); + devnode_clear(vdev); mutex_unlock(&videodev_lock); /* Mark this video device as never having been registered. */ vdev->minor = -1; -- cgit v1.2.3 From 6b5270d21202fcf6ae16a6266fed83a30ccece7a Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Sun, 6 Sep 2009 07:54:00 -0300 Subject: V4L/DVB (12725): v4l: warn when desired devnodenr is in use & add _no_warn function Warn when the desired device node number is already in use, except when the new video_register_device_no_warn function is called since in some use-cases that warning is not relevant. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/video4linux/v4l2-framework.txt | 22 ++++++++++++++++------ drivers/media/video/cx18/cx18-streams.c | 2 +- drivers/media/video/ivtv/ivtv-streams.c | 2 +- drivers/media/video/v4l2-dev.c | 20 +++++++++++++++++++- include/media/v4l2-dev.h | 4 ++++ 5 files changed, 41 insertions(+), 9 deletions(-) (limited to 'drivers/media/video/v4l2-dev.c') diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt index 38b3716d8643..b806edaf3e75 100644 --- a/Documentation/video4linux/v4l2-framework.txt +++ b/Documentation/video4linux/v4l2-framework.txt @@ -486,17 +486,27 @@ VFL_TYPE_RADIO: radioX for radio tuners VFL_TYPE_VTX: vtxX for teletext devices (deprecated, don't use) The last argument gives you a certain amount of control over the device -device node number used (i.e. the X in videoX). Normally you will pass -1 to -let the v4l2 framework pick the first free number. But if a driver creates -many devices, then it can be useful to have different video devices in -separate ranges. For example, video capture devices start at 0, video -output devices start at 16. - +device node number used (i.e. the X in videoX). Normally you will pass -1 +to let the v4l2 framework pick the first free number. But sometimes users +want to select a specific node number. It is common that drivers allow +the user to select a specific device node number through a driver module +option. That number is then passed to this function and video_register_device +will attempt to select that device node number. If that number was already +in use, then the next free device node number will be selected and it +will send a warning to the kernel log. + +Another use-case is if a driver creates many devices. In that case it can +be useful to place different video devices in separate ranges. For example, +video capture devices start at 0, video output devices start at 16. So you can use the last argument to specify a minimum device node number and the v4l2 framework will try to pick the first free number that is equal or higher to what you passed. If that fails, then it will just pick the first free number. +Since in this case you do not care about a warning about not being able +to select the specified device node number, you can call the function +video_register_device_no_warn() instead. + Whenever a device node is created some attributes are also created for you. If you look in /sys/class/video4linux you see the devices. Go into e.g. video0 and you will see 'name' and 'index' attributes. The 'name' attribute diff --git a/drivers/media/video/cx18/cx18-streams.c b/drivers/media/video/cx18/cx18-streams.c index 6c988b95adc6..7df513a2dba8 100644 --- a/drivers/media/video/cx18/cx18-streams.c +++ b/drivers/media/video/cx18/cx18-streams.c @@ -245,7 +245,7 @@ static int cx18_reg_dev(struct cx18 *cx, int type) video_set_drvdata(s->video_dev, s); /* Register device. First try the desired minor, then any free one. */ - ret = video_register_device(s->video_dev, vfl_type, num); + ret = video_register_device_no_warn(s->video_dev, vfl_type, num); if (ret < 0) { CX18_ERR("Couldn't register v4l2 device for %s (device node number %d)\n", s->name, num); diff --git a/drivers/media/video/ivtv/ivtv-streams.c b/drivers/media/video/ivtv/ivtv-streams.c index 23400035240a..67699e3f2aaa 100644 --- a/drivers/media/video/ivtv/ivtv-streams.c +++ b/drivers/media/video/ivtv/ivtv-streams.c @@ -261,7 +261,7 @@ static int ivtv_reg_dev(struct ivtv *itv, int type) video_set_drvdata(s->vdev, s); /* Register device. First try the desired minor, then any free one. */ - if (video_register_device(s->vdev, vfl_type, num)) { + if (video_register_device_no_warn(s->vdev, vfl_type, num)) { IVTV_ERR("Couldn't register v4l2 device for %s (device node number %d)\n", s->name, num); video_device_release(s->vdev); diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c index 4715f08157bc..500cbe9891ac 100644 --- a/drivers/media/video/v4l2-dev.c +++ b/drivers/media/video/v4l2-dev.c @@ -382,6 +382,8 @@ static int get_index(struct video_device *vdev) * @type: type of device to register * @nr: which device node number (0 == /dev/video0, 1 == /dev/video1, ... * -1 == first free) + * @warn_if_nr_in_use: warn if the desired device node number + * was already in use and another number was chosen instead. * * The registration code assigns minor numbers and device node numbers * based on the requested type and registers the new device node with @@ -401,7 +403,8 @@ static int get_index(struct video_device *vdev) * * %VFL_TYPE_RADIO - A radio card */ -int video_register_device(struct video_device *vdev, int type, int nr) +static int __video_register_device(struct video_device *vdev, int type, int nr, + int warn_if_nr_in_use) { int i = 0; int ret; @@ -547,6 +550,10 @@ int video_register_device(struct video_device *vdev, int type, int nr) reference to the device goes away. */ vdev->dev.release = v4l2_device_release; + if (nr != -1 && nr != vdev->num && warn_if_nr_in_use) + printk(KERN_WARNING "%s: requested %s%d, got %s%d\n", + __func__, name_base, nr, name_base, vdev->num); + /* Part 5: Activate this minor. The char device can now be used. */ mutex_lock(&videodev_lock); video_device[vdev->minor] = vdev; @@ -563,8 +570,19 @@ cleanup: vdev->minor = -1; return ret; } + +int video_register_device(struct video_device *vdev, int type, int nr) +{ + return __video_register_device(vdev, type, nr, 1); +} EXPORT_SYMBOL(video_register_device); +int video_register_device_no_warn(struct video_device *vdev, int type, int nr) +{ + return __video_register_device(vdev, type, nr, 0); +} +EXPORT_SYMBOL(video_register_device_no_warn); + /** * video_unregister_device - unregister a video4linux device * @vdev: the device to unregister diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h index 255f6442b635..73c9867d744c 100644 --- a/include/media/v4l2-dev.h +++ b/include/media/v4l2-dev.h @@ -101,6 +101,10 @@ struct video_device Also note that vdev->minor is set to -1 if the registration failed. */ int __must_check video_register_device(struct video_device *vdev, int type, int nr); +/* Same as video_register_device, but no warning is issued if the desired + device node number was already in use. */ +int __must_check video_register_device_no_warn(struct video_device *vdev, int type, int nr); + /* Unregister video devices. Will do nothing if vdev == NULL or vdev->minor < 0. */ void video_unregister_device(struct video_device *vdev); -- cgit v1.2.3