diff options
author | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-09-24 21:22:33 +0100 |
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committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-09-24 21:22:33 +0100 |
commit | baea7b946f00a291b166ccae7fcfed6c01530cc6 (patch) | |
tree | 4aa275fbdbec9c7b9b4629e8bee2bbecd3c6a6af /drivers/media/video/v4l2-dev.c | |
parent | ae19ffbadc1b2100285a5b5b3d0a4e0a11390904 (diff) | |
parent | 94e0fb086fc5663c38bbc0fe86d698be8314f82f (diff) |
Merge branch 'origin' into for-linus
Conflicts:
MAINTAINERS
Diffstat (limited to 'drivers/media/video/v4l2-dev.c')
-rw-r--r-- | drivers/media/video/v4l2-dev.c | 154 |
1 files changed, 96 insertions, 58 deletions
diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c index a7f1b69a7da..500cbe9891a 100644 --- a/drivers/media/video/v4l2-dev.c +++ b/drivers/media/video/v4l2-dev.c @@ -66,7 +66,49 @@ 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); + +/* 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) { @@ -119,8 +161,8 @@ 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 */ + devnode_clear(vdev); mutex_unlock(&videodev_lock); @@ -299,32 +341,28 @@ 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. + * + * 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 -ENFILE if num is already in use, a free index number if - * successful. + * 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); @@ -335,35 +373,23 @@ 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, ... + * @nr: which device node number (0 == /dev/video0, 1 == /dev/video1, ... * -1 == first free) - * @index: stream number based on parent device; - * -1 if auto assign, requested number otherwise + * @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 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. * @@ -377,8 +403,8 @@ 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) +static int __video_register_device(struct video_device *vdev, int type, int nr, + int warn_if_nr_in_use) { int i = 0; int ret; @@ -421,7 +447,7 @@ int video_register_device_index(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. @@ -452,21 +478,22 @@ int video_register_device_index(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 = devnode_find(vdev, nr == -1 ? 0 : nr, minor_cnt); if (nr == minor_cnt) - nr = find_first_zero_bit(video_nums[type], minor_cnt); + nr = devnode_find(vdev, 0, 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; @@ -478,17 +505,13 @@ int video_register_device_index(struct video_device *vdev, int type, int nr, #endif vdev->minor = i + minor_offset; vdev->num = nr; - set_bit(nr, video_nums[type]); + devnode_set(vdev); + /* 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) { @@ -517,7 +540,7 @@ int video_register_device_index(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__); @@ -527,6 +550,10 @@ int video_register_device_index(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; @@ -537,13 +564,24 @@ cleanup: mutex_lock(&videodev_lock); if (vdev->cdev) cdev_del(vdev->cdev); - clear_bit(vdev->num, video_nums[type]); + devnode_clear(vdev); mutex_unlock(&videodev_lock); /* Mark this video device as never having been registered. */ vdev->minor = -1; return ret; } -EXPORT_SYMBOL(video_register_device_index); + +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 |