/* * scull.h -- definitions for the char module * * Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet * Copyright (C) 2001 O'Reilly & Associates * * The source code in this file can be freely used, adapted, * and redistributed in source or binary form, so long as an * acknowledgment appears in derived source files.  The citation * should list that the code comes from the book "Linux Device * Drivers" by Alessandro Rubini and Jonathan Corbet, published * by O'Reilly & Associates.   No warranty is attached; * we cannot take responsibility for errors or fitness for use. * * $Id: scull.h,v 1.15 2004/11/04 17:51:18 rubini Exp $ */#ifndef _SCULL_H_#define _SCULL_H_#include <linux/ioctl.h> /* needed for the _IOW etc stuff used later *//* * 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		/* 每個指針(量子)指向一個4000字節(jié)的區(qū)域 */#endif#ifndef SCULL_QSET#define SCULL_QSET    1000		/* 一個有1000個(量子)的指針數(shù)組 */#endif/* * The pipe device is a simple circular buffer. Here its default size */#ifndef SCULL_P_BUFFER#define SCULL_P_BUFFER 4000#endif/* * Representation of scull quantum sets. * 一個鏈表項 */struct scull_qset {	void **data;	struct scull_qset *next;	/* 下一個鏈表節(jié)點（鏈表項） */};/* 我們自己的設(shè)備(包含了基本的cdev字符設(shè)備結(jié)構(gòu)) */struct scull_dev {	struct scull_qset *data;  /* Pointer to first quantum set (鏈表的頭)*/	int quantum;              /* the current quantum size */	int qset;                 /* the current array size */	unsigned long size;       /* amount of data stored here (保存在其中的數(shù)據(jù)總量)*/	unsigned int access_key;  /* used by sculluid and scullpriv */	struct semaphore sem;     /* mutual exclusion semaphore     */	struct cdev cdev;	  /* Char device structure		*/};/* * Split minors in two parts */#define TYPE(minor)	(((minor) >> 4) & 0xf)	/* high nibble */#define NUM(minor)	((minor) & 0xf)		/* low  nibble *//* * 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_buffer;	/* pipe.c *//* * Prototypes for shared functions */int     scull_p_init(dev_t dev);void    scull_p_cleanup(void);int     scull_access_init(dev_t dev);void    scull_access_cleanup(void);int     scull_trim(struct scull_dev *dev);ssize_t scull_read(struct file *filp, char __user *buf, size_t count,                   loff_t *f_pos);ssize_t scull_write(struct file *filp, const char __user *buf, size_t count,                    loff_t *f_pos);loff_t  scull_llseek(struct file *filp, loff_t off, int whence);int     scull_ioctl(struct inode *inode, struct file *filp,                    unsigned int cmd, unsigned long arg);/* * Ioctl definitions *//* Use 'k' as magic number */#define SCULL_IOC_MAGIC  'k'/* Please use a different 8-bit number in your code */#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": switch G and S atomically * H means "sHift": switch T and Q atomically */#define SCULL_IOCSQUANTUM _IOW(SCULL_IOC_MAGIC,  1, int)#define SCULL_IOCSQSET    _IOW(SCULL_IOC_MAGIC,  2, int)#define SCULL_IOCTQUANTUM _IO(SCULL_IOC_MAGIC,   3)#define SCULL_IOCTQSET    _IO(SCULL_IOC_MAGIC,   4)#define SCULL_IOCGQUANTUM _IOR(SCULL_IOC_MAGIC,  5, int)#define SCULL_IOCGQSET    _IOR(SCULL_IOC_MAGIC,  6, int)#define SCULL_IOCQQUANTUM _IO(SCULL_IOC_MAGIC,   7)#define SCULL_IOCQQSET    _IO(SCULL_IOC_MAGIC,   8)#define SCULL_IOCXQUANTUM _IOWR(SCULL_IOC_MAGIC, 9, int)#define SCULL_IOCXQSET    _IOWR(SCULL_IOC_MAGIC,10, int)#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_IOC_MAXNR 14#endif /* _SCULL_H_ */