/* * scull.h -- definitions for the char module * *********/#include <linux/ioctl.h>/* version dependencies have been confined to a separate file */#define VERSION_CODE(vers,rel,seq) ( ((vers)<<16) | ((rel)<<8) | (seq) )#include "sysdep.h"/* * Macros to help debugging */#undef PDEBUG             /* undef it, just in case */#ifdef SCULL_DEBUG#  ifdef __KERNEL__     /* This one if debugging is on, and kernel space */#    define PDEBUG(fmt, args...) printk( KERN_DEBUG "scull: " fmt, ## args)#  else     /* This one for user space */#    define PDEBUG(fmt, args...) fprintf(stderr, fmt, ## args)#  endif#else#  define PDEBUG(fmt, args...) /* not debugging: nothing */#endif#undef PDEBUGG#define PDEBUGG(fmt, args...) /* nothing: it's a placeholder */#ifndef SCULL_MAJOR#define SCULL_MAJOR 0   /* dynamic major by default */#endif#ifndef SCULL_NR_DEVS#define SCULL_NR_DEVS 4    /* scull0 through scull3 */#endif#ifndef SCULL_P_NR_DEVS#define SCULL_P_NR_DEVS 4  /* scullpipe0 through scullpipe3 */#endif/* * The bare device is a variable-length region of memory. * Use a linked list of indirect blocks. * * "Scull_Dev->data" points to an array of pointers, each * pointer refers to a memory area of SCULL_QUANTUM bytes. * * The array (quantum-set) is SCULL_QSET long. */#ifndef SCULL_QUANTUM#define SCULL_QUANTUM 4000#endif#ifndef SCULL_QSET#define SCULL_QSET    1000#endif/* * The pipe device is a simple circular buffer. Here its default size */#ifndef SCULL_P_BUFFER#define SCULL_P_BUFFER 4000#endiftypedef struct Scull_Dev {   void **data;   struct Scull_Dev *next;   /* next listitem */   int quantum;              /* the current quantum size */   int qset;                 /* the current array size */   unsigned long size;   unsigned int access_key;  /* used by sculluid and scullpriv */   unsigned int usage;       /* lock the device while using it */} Scull_Dev;/* * Split minors in two parts */#define TYPE(dev)   (MINOR(dev) >> 4)  /* high nibble */#define NUM(dev)    (MINOR(dev) & 0xf) /* low  nibble *//* * Different minors behave differently, so let's use multiple fops */extern struct file_operations scull_fops;        /* simplest: global */extern struct file_operations scull_priv_fops;   /* private region   */extern struct file_operations scull_pipe_fops;   /* circular buffer  */extern struct file_operations scull_sngl_fops;   /* single open      */extern struct file_operations scull_user_fops;   /* single process   */extern struct file_operations scull_wusr_fops;   /* single user      *//* * The different configurable parameters */extern int scull_major;     /* main.c */extern int scull_nr_devs;extern int scull_quantum;extern int scull_qset;extern int scull_p_nr_devs;    /* pipe.c */extern int scull_p_buffer;/* * Prototypes for shared functions */int scull_p_init(void);void scull_p_cleanup(void);int scull_access_init(void);void scull_access_cleanup(void);int scull_trim(Scull_Dev *dev);read_write_t scull_read (struct inode *inode, struct file *filp,                char *buf, count_t count);read_write_t scull_write (struct inode *inode, struct file *filp,                const char *buf, count_t count);int scull_lseek (struct inode *inode, struct file *filp,                 off_t off, int whence);int scull_ioctl (struct inode *inode, struct file *filp,                 unsigned int cmd, unsigned long arg);#ifdef SCULL_DEBUG#  if LINUX_VERSION_CODE > VERSION_CODE(1,99,3) /* 1.99.4 exported the needed symbols */#    define SCULL_USE_PROC#  endif#endif#ifndef min#  define min(a,b) ((a)<(b) ? (a) : (b))#endif/* * Ioctl definitions *//* Use 'k' as magic number */#define SCULL_IOC_MAGIC  'k'#define SCULL_IOCRESET    _IO(SCULL_IOC_MAGIC, 0)/* * S means "Set" through a ptr, * T means "Tell" directly with the argument value * G means "Get": reply by setting through a pointer * Q means "Query": response is on the return value * X means "eXchange": G and S atomically * H means "sHift": T and Q atomically */#define SCULL_IOCSQUANTUM _IOW(SCULL_IOC_MAGIC,  1, scull_quantum)#define SCULL_IOCSQSET    _IOW(SCULL_IOC_MAGIC,  2, scull_qset)#define SCULL_IOCTQUANTUM _IO(SCULL_IOC_MAGIC,   3)#define SCULL_IOCTQSET    _IO(SCULL_IOC_MAGIC,   4)#define SCULL_IOCGQUANTUM _IOR(SCULL_IOC_MAGIC,  5, scull_quantum)#define SCULL_IOCGQSET    _IOR(SCULL_IOC_MAGIC,  6, scull_qset)#define SCULL_IOCQQUANTUM _IO(SCULL_IOC_MAGIC,   7)#define SCULL_IOCQQSET    _IO(SCULL_IOC_MAGIC,   8)#define SCULL_IOCXQUANTUM _IOWR(SCULL_IOC_MAGIC, 9, scull_quantum)#define SCULL_IOCXQSET    _IOWR(SCULL_IOC_MAGIC,10, scull_qset)#define SCULL_IOCHQUANTUM _IO(SCULL_IOC_MAGIC,  11)#define SCULL_IOCHQSET    _IO(SCULL_IOC_MAGIC,  12)/* * The other entities only have "Tell" and "Query", because they're * not printed in the book, and there's no need to have all six. * (The previous stuff was only there to show different ways to do it. */#define SCULL_P_IOCTSIZE _IO(SCULL_IOC_MAGIC,   13)#define SCULL_P_IOCQSIZE _IO(SCULL_IOC_MAGIC,   14)/* ... more to come */#define SCULL_IOCHARDRESET _IO(SCULL_IOC_MAGIC, 15) /* debugging tool */#define SCULL_IOC_MAXNR 15