/*
* linux/kernel/floppy.c
*
* (C) 1991 Linus Torvalds
*/
/*
* 02.12.91 - Changed to static variables to indicate need for reset
* and recalibrate. This makes some things easier (output_byte reset
* checking etc), and means less interrupt jumping in case of errors,
* so the code is hopefully easier to understand.
*/
/*
* This file is certainly a mess. I've tried my best to get it working,
* but I don't like programming floppies, and I have only one anyway.
* Urgel. I should check for more errors, and do more graceful error
* recovery. Seems there are problems with several drives. I've tried to
* correct them. No promises.
*/
/*
* As with hd.c, all routines within this file can (and will) be called
* by interrupts, so extreme caution is needed. A hardware interrupt
* handler may not sleep, or a kernel panic will happen. Thus I cannot
* call "floppy-on" directly, but have to set a special timer interrupt
* etc.
*
* Also, I'm not certain this works on more than 1 floppy. Bugs may
* abund.
*/
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/fdreg.h> // 软驱头文件，其中包含软驱的常用函数的定义
#include <asm/system.h>
#include <asm/io.h>
#include <asm/segment.h>
#define MAJOR_NR 2 // 软驱主设备号
#include "blk.h"
/* 全局标志变量 */
static int recalibrate = 0; // 需要重新校正
static int reset = 0; // 需要重新置位
static int seek = 0; // 寻道
extern unsigned char current_DOR; // 在文件sched.c中定义
#define immoutb_p(val,port) \ // 字节val直接输出到port
__asm__("outb %0,%1\n\tjmp 1f\n1:\tjmp 1f\n1:"::"a" ((char) (val)),"i" (port))
#define TYPE(x) ((x)>>2) // 软驱类型，2--1.2MB，7--1.44MB
#define DRIVE(x) ((x)&0x03) // 软驱序列号0-3对应A-D
/*
* Note that MAX_ERRORS=8
