/* *  linux/kernel/hd.c * *  (C) 1991  Linus Torvalds *//* * This is the low-level hd interrupt support. It traverses the * request-list, using interrupts to jump between functions. As * all the functions are called within interrupts, we may not * sleep. Special care is recommended. *  *  modified by Drew Eckhardt to check nr of hd's from the CMOS. */#include <linux/config.h>#include <linux/sched.h>#include <linux/fs.h>#include <linux/kernel.h>#include <linux/hdreg.h>#include <asm/system.h>#include <asm/io.h>#include <asm/segment.h>#define MAJOR_NR 3#include "blk.h"#define CMOS_READ(addr) ({ \outb_p(0x80|addr,0x70); \inb_p(0x71); \})/* Max read/write errors/sector */#define MAX_ERRORS	7#define MAX_HD		2static void recal_intr(void);static int recalibrate = 1;static int reset = 1;/* *  This struct defines the HD's and their types. */struct hd_i_struct {	int head,sect,cyl,wpcom,lzone,ctl;	};#ifdef HD_TYPEstruct hd_i_struct hd_info[] = { HD_TYPE };#define NR_HD ((sizeof (hd_info))/(sizeof (struct hd_i_struct)))#elsestruct hd_i_struct hd_info[] = { {0,0,0,0,0,0},{0,0,0,0,0,0} };static int NR_HD = 0;#endifstatic struct hd_struct {	long start_sect;	long nr_sects;} hd[5*MAX_HD]={{0,0},};#define port_read(port,buf,nr) \__asm__("cld;rep;insw"::"d" (port),"D" (buf),"c" (nr):"cx","di")#define port_write(port,buf,nr) \__asm__("cld;rep;outsw"::"d" (port),"S" (buf),"c" (nr):"cx","si")extern void hd_interrupt(void);extern void rd_load(void);/* This may be used only once, enforced by 'static int callable' */int sys_setup(void * BIOS){	static int callable = 1;	int i,drive;	unsigned char cmos_disks;	struct partition *p;	struct buffer_head * bh;	if (!callable)		return -1;	callable = 0;#ifndef HD_TYPE	for (drive=0 ; drive<2 ; drive++) {		hd_info[drive].cyl = *(unsigned short *) BIOS;		hd_info[drive].head = *(unsigned char *) (2+BIOS);		hd_info[drive].wpcom = *(unsigned short *) (5+BIOS);		hd_info[drive].ctl = *(unsigned char *) (8+BIOS);		hd_info[drive].lzone = *(unsigned short *) (12+BIOS);		hd_info[drive].sect = *(unsigned char *) (14+BIOS);		BIOS += 16;	}	if (hd_info[1].cyl)		NR_HD=2;	else		NR_HD=1;#endif	for (i=0 ; i<NR_HD ; i++) {		hd[i*5].start_sect = 0;		hd[i*5].nr_sects = hd_info[i].head*				hd_info[i].sect*hd_info[i].cyl;	}	/*		We querry CMOS about hard disks : it could be that 		we have a SCSI/ESDI/etc controller that is BIOS		compatable with ST-506, and thus showing up in our		BIOS table, but not register compatable, and therefore		not present in CMOS.		Furthurmore, we will assume that our ST-506 drives		<if any> are the primary drives in the system, and 		the ones reflected as drive 1 or 2.		The first drive is stored in the high nibble of CMOS		byte 0x12, the second in the low nibble.  This will be		either a 4 bit drive type or 0xf indicating use byte 0x19 		for an 8 bit type, drive 1, 0x1a for drive 2 in CMOS.		Needless to say, a non-zero value means we have 		an AT controller hard disk for that drive.			*/	if ((cmos_disks = CMOS_READ(0x12)) & 0xf0)		if (cmos_disks & 0x0f)			NR_HD = 2;		else			NR_HD = 1;	else		NR_HD = 0;	for (i = NR_HD ; i < 2 ; i++) {		hd[i*5].start_sect = 0;		hd[i*5].nr_sects = 0;	}	for (drive=0 ; drive<NR_HD ; drive++) {		if (!(bh = bread(0x300 + drive*5,0))) {			printk("Unable to read partition table of drive %d\n\r",				drive);			panic("");		}		if (bh->b_data[510] != 0x55 || (unsigned char)		    bh->b_data[511] != 0xAA) {			printk("Bad partition table on drive %d\n\r",drive);			panic("");		}		p = 0x1BE + (void *)bh->b_data;		for (i=1;i<5;i++,p++) {			hd[i+5*drive].start_sect = p->start_sect;			hd[i+5*drive].nr_sects = p->nr_sects;		}		brelse(bh);	}	if (NR_HD)		printk("Partition table%s ok.\n\r",(NR_HD>1)?"s":"");	rd_load();	mount_root();	return (0);}static int controller_ready(void){	int retries=10000;	while (--retries && (inb_p(HD_STATUS)&0xc0)!=0x40);	return (retries);}static int win_result(void){	int i=inb_p(HD_STATUS);	if ((i & (BUSY_STAT | READY_STAT | WRERR_STAT | SEEK_STAT | ERR_STAT))		== (READY_STAT | SEEK_STAT))		return(0); /* ok */	if (i&1) i=inb(HD_ERROR);	return (1);}static void hd_out(unsigned int drive,unsigned int nsect,unsigned int sect,		unsigned int head,unsigned int cyl,unsigned int cmd,		void (*intr_addr)(void)){	register int port asm("dx");	if (drive>1 || head>15)		panic("Trying to write bad sector");	if (!controller_ready())		panic("HD controller not ready");	do_hd = intr_addr;	outb_p(hd_info[drive].ctl,HD_CMD);	port=HD_DATA;	outb_p(hd_info[drive].wpcom>>2,++port);	outb_p(nsect,++port);	outb_p(sect,++port);	outb_p(cyl,++port);	outb_p(cyl>>8,++port);	outb_p(0xA0|(drive<<4)|head,++port);	outb(cmd,++port);}static int drive_busy(void){	unsigned int i;	for (i = 0; i < 10000; i++)		if (READY_STAT == (inb_p(HD_STATUS) & (BUSY_STAT|READY_STAT)))			break;	i = inb(HD_STATUS);	i &= BUSY_STAT | READY_STAT | SEEK_STAT;	if (i == READY_STAT | SEEK_STAT)		return(0);	printk("HD controller times out\n\r");	return(1);}static void reset_controller(void){	int	i;	outb(4,HD_CMD);	for(i = 0; i < 100; i++) nop();	outb(hd_info[0].ctl & 0x0f ,HD_CMD);	if (drive_busy())		printk("HD-controller still busy\n\r");	if ((i = inb(HD_ERROR)) != 1)		printk("HD-controller reset failed: %02x\n\r",i);}static void reset_hd(int nr){	reset_controller();	hd_out(nr,hd_info[nr].sect,hd_info[nr].sect,hd_info[nr].head-1,		hd_info[nr].cyl,WIN_SPECIFY,&recal_intr);}void unexpected_hd_interrupt(void){	printk("Unexpected HD interrupt\n\r");}static void bad_rw_intr(void){	if (++CURRENT->errors >= MAX_ERRORS)		end_request(0);	if (CURRENT->errors > MAX_ERRORS/2)		reset = 1;}static void read_intr(void){	if (win_result()) {		bad_rw_intr();		do_hd_request();		return;	}	port_read(HD_DATA,CURRENT->buffer,256);	CURRENT->errors = 0;	CURRENT->buffer += 512;	CURRENT->sector++;	if (--CURRENT->nr_sectors) {		do_hd = &read_intr;		return;	}	end_request(1);	do_hd_request();}static void write_intr(void){	if (win_result()) {		bad_rw_intr();		do_hd_request();		return;	}	if (--CURRENT->nr_sectors) {		CURRENT->sector++;		CURRENT->buffer += 512;		do_hd = &write_intr;		port_write(HD_DATA,CURRENT->buffer,256);		return;	}	end_request(1);	do_hd_request();}static void recal_intr(void){	if (win_result())		bad_rw_intr();	do_hd_request();}void do_hd_request(void){	int i,r;	unsigned int block,dev;	unsigned int sec,head,cyl;	unsigned int nsect;	INIT_REQUEST;	dev = MINOR(CURRENT->dev);	block = CURRENT->sector;	if (dev >= 5*NR_HD || block+2 > hd[dev].nr_sects) {		end_request(0);		goto repeat;	}	block += hd[dev].start_sect;	dev /= 5;	__asm__("divl %4":"=a" (block),"=d" (sec):"0" (block),"1" (0),		"r" (hd_info[dev].sect));	__asm__("divl %4":"=a" (cyl),"=d" (head):"0" (block),"1" (0),		"r" (hd_info[dev].head));	sec++;	nsect = CURRENT->nr_sectors;	if (reset) {		reset = 0;		recalibrate = 1;		reset_hd(CURRENT_DEV);		return;	}	if (recalibrate) {		recalibrate = 0;		hd_out(dev,hd_info[CURRENT_DEV].sect,0,0,0,			WIN_RESTORE,&recal_intr);		return;	}		if (CURRENT->cmd == WRITE) {		hd_out(dev,nsect,sec,head,cyl,WIN_WRITE,&write_intr);		for(i=0 ; i<3000 && !(r=inb_p(HD_STATUS)&DRQ_STAT) ; i++)			/* nothing */ ;		if (!r) {			bad_rw_intr();			goto repeat;		}		port_write(HD_DATA,CURRENT->buffer,256);	} else if (CURRENT->cmd == READ) {		hd_out(dev,nsect,sec,head,cyl,WIN_READ,&read_intr);	} else		panic("unknown hd-command");}void hd_init(void){	blk_dev[MAJOR_NR].request_fn = DEVICE_REQUEST;	set_intr_gate(0x2E,&hd_interrupt);	outb_p(inb_p(0x21)&0xfb,0x21);	outb(inb_p(0xA1)&0xbf,0xA1);}