cregit-Linux how code gets into the kernel

Release 4.12 include/media/lirc_dev.h

Directory: include/media
 * LIRC base driver
 * by Artur Lipowski <>
 *        This code is licensed under GNU GPL




#define BUFLEN            16

#define mod(n, div) ((n) % (div))

#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/poll.h>
#include <linux/kfifo.h>
#include <media/lirc.h>

struct lirc_buffer {
wait_queue_head_t wait_poll;
spinlock_t fifo_lock;
unsigned int chunk_size;
unsigned int size; /* in chunks */
	/* Using chunks instead of bytes pretends to simplify boundary checking
         * And should allow for some performance fine tunning later */
struct kfifo fifo;

static inline void lirc_buffer_clear(struct lirc_buffer *buf) { unsigned long flags; if (kfifo_initialized(&buf->fifo)) { spin_lock_irqsave(&buf->fifo_lock, flags); kfifo_reset(&buf->fifo); spin_unlock_irqrestore(&buf->fifo_lock, flags); } else WARN(1, "calling %s on an uninitialized lirc_buffer\n", __func__); }


Jarod Wilson6192.42%150.00%
Martin Kaiser57.58%150.00%

static inline int lirc_buffer_init(struct lirc_buffer *buf, unsigned int chunk_size, unsigned int size) { int ret; init_waitqueue_head(&buf->wait_poll); spin_lock_init(&buf->fifo_lock); buf->chunk_size = chunk_size; buf->size = size; ret = kfifo_alloc(&buf->fifo, size * chunk_size, GFP_KERNEL); return ret; }


Jarod Wilson70100.00%1100.00%

static inline void lirc_buffer_free(struct lirc_buffer *buf) { if (kfifo_initialized(&buf->fifo)) { kfifo_free(&buf->fifo); } else WARN(1, "calling %s on an uninitialized lirc_buffer\n", __func__); }


Jarod Wilson3788.10%150.00%
Martin Kaiser511.90%150.00%

static inline int lirc_buffer_len(struct lirc_buffer *buf) { int len; unsigned long flags; spin_lock_irqsave(&buf->fifo_lock, flags); len = kfifo_len(&buf->fifo); spin_unlock_irqrestore(&buf->fifo_lock, flags); return len; }


Jarod Wilson52100.00%1100.00%

static inline int lirc_buffer_full(struct lirc_buffer *buf) { return lirc_buffer_len(buf) == buf->size * buf->chunk_size; }


Jarod Wilson26100.00%1100.00%

static inline int lirc_buffer_empty(struct lirc_buffer *buf) { return !lirc_buffer_len(buf); }


Jarod Wilson19100.00%1100.00%

static inline int lirc_buffer_available(struct lirc_buffer *buf) { return buf->size - (lirc_buffer_len(buf) / buf->chunk_size); }


Jarod Wilson28100.00%1100.00%

static inline unsigned int lirc_buffer_read(struct lirc_buffer *buf, unsigned char *dest) { unsigned int ret = 0; if (lirc_buffer_len(buf) >= buf->chunk_size) ret = kfifo_out_locked(&buf->fifo, dest, buf->chunk_size, &buf->fifo_lock); return ret; }


Jarod Wilson59100.00%1100.00%

static inline unsigned int lirc_buffer_write(struct lirc_buffer *buf, unsigned char *orig) { unsigned int ret; ret = kfifo_in_locked(&buf->fifo, orig, buf->chunk_size, &buf->fifo_lock); return ret; }


Jarod Wilson46100.00%1100.00%

/** * struct lirc_driver - Defines the parameters on a LIRC driver * * @name: this string will be used for logs * * @minor: indicates minor device (/dev/lirc) number for * registered driver if caller fills it with negative * value, then the first free minor number will be used * (if available). * * @code_length: length of the remote control key code expressed in bits. * * @buffer_size: Number of FIFO buffers with @chunk_size size. If zero, * creates a buffer with BUFLEN size (16 bytes). * * @sample_rate: if zero, the device will wait for an event with a new * code to be parsed. Otherwise, specifies the sample * rate for polling. Value should be between 0 * and HZ. If equal to HZ, it would mean one polling per * second. * * @features: lirc compatible hardware features, like LIRC_MODE_RAW, * LIRC_CAN\_\*, as defined at include/media/lirc.h. * * @chunk_size: Size of each FIFO buffer. * * @data: it may point to any driver data and this pointer will * be passed to all callback functions. * * @min_timeout: Minimum timeout for record. Valid only if * LIRC_CAN_SET_REC_TIMEOUT is defined. * * @max_timeout: Maximum timeout for record. Valid only if * LIRC_CAN_SET_REC_TIMEOUT is defined. * * @add_to_buf: add_to_buf will be called after specified period of the * time or triggered by the external event, this behavior * depends on value of the sample_rate this function will * be called in user context. This routine should return * 0 if data was added to the buffer and -ENODATA if none * was available. This should add some number of bits * evenly divisible by code_length to the buffer. * * @rbuf: if not NULL, it will be used as a read buffer, you will * have to write to the buffer by other means, like irq's * (see also lirc_serial.c). * * @set_use_inc: set_use_inc will be called after device is opened * * @set_use_dec: set_use_dec will be called after device is closed * * @rdev: Pointed to struct rc_dev associated with the LIRC * device. * * @fops: file_operations for drivers which don't fit the current * driver model. * Some ioctl's can be directly handled by lirc_dev if the * driver's ioctl function is NULL or if it returns * -ENOIOCTLCMD (see also lirc_serial.c). * * @dev: pointer to the struct device associated with the LIRC * device. * * @owner: the module owning this struct */ struct lirc_driver { char name[40]; int minor; __u32 code_length; unsigned int buffer_size; /* in chunks holding one code each */ int sample_rate; __u32 features; unsigned int chunk_size; void *data; int min_timeout; int max_timeout; int (*add_to_buf)(void *data, struct lirc_buffer *buf); struct lirc_buffer *rbuf; int (*set_use_inc)(void *data); void (*set_use_dec)(void *data); struct rc_dev *rdev; const struct file_operations *fops; struct device *dev; struct module *owner; }; /* following functions can be called ONLY from user context * * returns negative value on error or minor number * of the registered device if success * contents of the structure pointed by p is copied */ extern int lirc_register_driver(struct lirc_driver *d); /* returns negative value on error or 0 if success */ extern int lirc_unregister_driver(int minor); /* Returns the private data stored in the lirc_driver * associated with the given device file pointer. */ void *lirc_get_pdata(struct file *file); /* default file operations * used by drivers if they override only some operations */ int lirc_dev_fop_open(struct inode *inode, struct file *file); int lirc_dev_fop_close(struct inode *inode, struct file *file); unsigned int lirc_dev_fop_poll(struct file *file, poll_table *wait); long lirc_dev_fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg); ssize_t lirc_dev_fop_read(struct file *file, char __user *buffer, size_t length, loff_t *ppos); ssize_t lirc_dev_fop_write(struct file *file, const char __user *buffer, size_t length, loff_t *ppos); #endif

Overall Contributors

Jarod Wilson69897.21%333.33%
Martin Kaiser101.39%111.11%
Srinivas Kandagatla50.70%111.11%
Dan Carpenter20.28%111.11%
Geert Uytterhoeven10.14%111.11%
Arnd Bergmann10.14%111.11%
Mauro Carvalho Chehab10.14%111.11%
Directory: include/media
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