xd.c

讲述linux的初始化过程

		xd_gendisk.part[minor].nr_sects = 0;
	};

	grok_partitions(&xd_gendisk, target, 1<<6,
			xd_info[target].heads * xd_info[target].cylinders * xd_info[target].sectors);

	xd_valid[target] = 1;
	wake_up(&xd_wait_open);

	return 0;
}

/* xd_readwrite: handle a read/write request */
static int xd_readwrite (u_char operation,u_char drive,char *buffer,u_int block,u_int count)
{
	u_char cmdblk[6],sense[4];
	u_short track,cylinder;
	u_char head,sector,control,mode = PIO_MODE,temp;
	char **real_buffer;
	register int i;
	
#ifdef DEBUG_READWRITE
	printk("xd_readwrite: operation = %s, drive = %d, buffer = 0x%X, block = %d, count = %d\n",operation == READ ? "read" : "write",drive,buffer,block,count);
#endif /* DEBUG_READWRITE */

	control = xd_info[drive].control;
	if (!xd_dma_buffer)
		xd_dma_buffer = (char *)xd_dma_mem_alloc(xd_maxsectors * 0x200);
	while (count) {
		temp = count < xd_maxsectors ? count : xd_maxsectors;

		track = block / xd_info[drive].sectors;
		head = track % xd_info[drive].heads;
		cylinder = track / xd_info[drive].heads;
		sector = block % xd_info[drive].sectors;

#ifdef DEBUG_READWRITE
		printk("xd_readwrite: drive = %d, head = %d, cylinder = %d, sector = %d, count = %d\n",drive,head,cylinder,sector,temp);
#endif /* DEBUG_READWRITE */

		if (xd_dma_buffer) {
			mode = xd_setup_dma(operation == READ ? DMA_MODE_READ : DMA_MODE_WRITE,(u_char *)(xd_dma_buffer),temp * 0x200);
			real_buffer = &xd_dma_buffer;
			for (i=0; i < (temp * 0x200); i++)
				xd_dma_buffer[i] = buffer[i];
		}
		else
			real_buffer = &buffer;

		xd_build(cmdblk,operation == READ ? CMD_READ : CMD_WRITE,drive,head,cylinder,sector,temp & 0xFF,control);

		switch (xd_command(cmdblk,mode,(u_char *)(*real_buffer),(u_char *)(*real_buffer),sense,XD_TIMEOUT)) {
			case 1:
				printk("xd%c: %s timeout, recalibrating drive\n",'a'+drive,(operation == READ ? "read" : "write"));
				xd_recalibrate(drive);
				return (0);
			case 2:
				if (sense[0] & 0x30) {
					printk("xd%c: %s - ",'a'+drive,(operation == READ ? "reading" : "writing"));
					switch ((sense[0] & 0x30) >> 4) {
					case 0: printk("drive error, code = 0x%X",sense[0] & 0x0F);
						break;
					case 1: printk("controller error, code = 0x%X",sense[0] & 0x0F);
						break;
					case 2: printk("command error, code = 0x%X",sense[0] & 0x0F);
						break;
					case 3: printk("miscellaneous error, code = 0x%X",sense[0] & 0x0F);
						break;
					}
				}
				if (sense[0] & 0x80)
					printk(" - CHS = %d/%d/%d\n",((sense[2] & 0xC0) << 2) | sense[3],sense[1] & 0x1F,sense[2] & 0x3F);
				/*	reported drive number = (sense[1] & 0xE0) >> 5 */
				else
					printk(" - no valid disk address\n");
				return (0);
		}
		if (xd_dma_buffer)
			for (i=0; i < (temp * 0x200); i++)
				buffer[i] = xd_dma_buffer[i];

		count -= temp, buffer += temp * 0x200, block += temp;
	}
	return (1);
}

/* xd_recalibrate: recalibrate a given drive and reset controller if necessary */
static void xd_recalibrate (u_char drive)
{
	u_char cmdblk[6];
	
	xd_build(cmdblk,CMD_RECALIBRATE,drive,0,0,0,0,0);
	if (xd_command(cmdblk,PIO_MODE,0,0,0,XD_TIMEOUT * 8))
		printk("xd%c: warning! error recalibrating, controller may be unstable\n", 'a'+drive);
}

/* xd_interrupt_handler: interrupt service routine */
static void xd_interrupt_handler(int irq, void *dev_id, struct pt_regs * regs)
{
	if (inb(XD_STATUS) & STAT_INTERRUPT) {							/* check if it was our device */
#ifdef DEBUG_OTHER
		printk("xd_interrupt_handler: interrupt detected\n");
#endif /* DEBUG_OTHER */
		outb(0,XD_CONTROL);								/* acknowledge interrupt */
		wake_up(&xd_wait_int);								/* and wake up sleeping processes */
	}
	else
		printk("xd: unexpected interrupt\n");
}

/* xd_setup_dma: set up the DMA controller for a data transfer */
static u_char xd_setup_dma (u_char mode,u_char *buffer,u_int count)
{
	unsigned long f;
	
	if (nodma)
		return (PIO_MODE);
	if (((unsigned long) buffer & 0xFFFF0000) != (((unsigned long) buffer + count) & 0xFFFF0000)) {
#ifdef DEBUG_OTHER
		printk("xd_setup_dma: using PIO, transfer overlaps 64k boundary\n");
#endif /* DEBUG_OTHER */
		return (PIO_MODE);
	}
	
	f=claim_dma_lock();
	disable_dma(xd_dma);
	clear_dma_ff(xd_dma);
	set_dma_mode(xd_dma,mode);
	set_dma_addr(xd_dma, (unsigned long) buffer);
	set_dma_count(xd_dma,count);
	
	release_dma_lock(f);

	return (DMA_MODE);			/* use DMA and INT */
}

/* xd_build: put stuff into an array in a format suitable for the controller */
static u_char *xd_build (u_char *cmdblk,u_char command,u_char drive,u_char head,u_short cylinder,u_char sector,u_char count,u_char control)
{
	cmdblk[0] = command;
	cmdblk[1] = ((drive & 0x07) << 5) | (head & 0x1F);
	cmdblk[2] = ((cylinder & 0x300) >> 2) | (sector & 0x3F);
	cmdblk[3] = cylinder & 0xFF;
	cmdblk[4] = count;
	cmdblk[5] = control;
	
	return (cmdblk);
}

/* xd_wakeup is called from timer interrupt */
static void xd_wakeup (unsigned long unused)
{
	wake_up(&xdc_wait);
}

/* xd_wakeup is called from timer interrupt */
static void xd_watchdog (unsigned long unused)
{
	xd_error = 1;
	wake_up(&xd_wait_int);
}

/* xd_waitport: waits until port & mask == flags or a timeout occurs. return 1 for a timeout */
static inline u_char xd_waitport (u_short port,u_char flags,u_char mask,u_long timeout)
{
	u_long expiry = jiffies + timeout;
	int success;

	xdc_busy = 1;
	while ((success = ((inb(port) & mask) != flags)) && time_before(jiffies, expiry)) {
		xd_timer.expires = jiffies;
		cli();
		add_timer(&xd_timer);
		sleep_on(&xdc_wait);
		del_timer(&xd_timer);
		sti();
	}
	xdc_busy = 0;
	return (success);
}

static inline u_int xd_wait_for_IRQ (void)
{
	unsigned long flags;
	xd_watchdog_int.expires = jiffies + 8 * HZ;
	add_timer(&xd_watchdog_int);
	
	flags=claim_dma_lock();
	enable_dma(xd_dma);
	release_dma_lock(flags);
	
	sleep_on(&xd_wait_int);
	del_timer(&xd_watchdog_int);
	xdc_busy = 0;
	
	flags=claim_dma_lock();
	disable_dma(xd_dma);
	release_dma_lock(flags);
	
	if (xd_error) {
		printk("xd: missed IRQ - command aborted\n");
		xd_error = 0;
		return (1);
	}
	return (0);
}

/* xd_command: handle all data transfers necessary for a single command */
static u_int xd_command (u_char *command,u_char mode,u_char *indata,u_char *outdata,u_char *sense,u_long timeout)
{
	u_char cmdblk[6],csb,complete = 0;

#ifdef DEBUG_COMMAND
	printk("xd_command: command = 0x%X, mode = 0x%X, indata = 0x%X, outdata = 0x%X, sense = 0x%X\n",command,mode,indata,outdata,sense);
#endif /* DEBUG_COMMAND */

	outb(0,XD_SELECT);
	outb(mode,XD_CONTROL);

	if (xd_waitport(XD_STATUS,STAT_SELECT,STAT_SELECT,timeout))
		return (1);

	while (!complete) {
		if (xd_waitport(XD_STATUS,STAT_READY,STAT_READY,timeout))
			return (1);

		switch (inb(XD_STATUS) & (STAT_COMMAND | STAT_INPUT)) {
			case 0:
				if (mode == DMA_MODE) {
					if (xd_wait_for_IRQ())
						return (1);
				} else
					outb(outdata ? *outdata++ : 0,XD_DATA);
				break;
			case STAT_INPUT:
				if (mode == DMA_MODE) {
					if (xd_wait_for_IRQ())
						return (1);
				} else
					if (indata)
						*indata++ = inb(XD_DATA);
					else
						inb(XD_DATA);
				break;
			case STAT_COMMAND:
				outb(command ? *command++ : 0,XD_DATA);
				break;
			case STAT_COMMAND | STAT_INPUT:
				complete = 1;
				break;
		}
	}
	csb = inb(XD_DATA);

	if (xd_waitport(XD_STATUS,0,STAT_SELECT,timeout))					/* wait until deselected */
		return (1);

	if (csb & CSB_ERROR) {									/* read sense data if error */
		xd_build(cmdblk,CMD_SENSE,(csb & CSB_LUN) >> 5,0,0,0,0,0);
		if (xd_command(cmdblk,0,sense,0,0,XD_TIMEOUT))
			printk("xd: warning! sense command failed!\n");
	}

#ifdef DEBUG_COMMAND
	printk("xd_command: completed with csb = 0x%X\n",csb);
#endif /* DEBUG_COMMAND */

	return (csb & CSB_ERROR);
}

static u_char __init xd_initdrives (void (*init_drive)(u_char drive))
{
	u_char cmdblk[6],i,count = 0;

	for (i = 0; i < XD_MAXDRIVES; i++) {
		xd_build(cmdblk,CMD_TESTREADY,i,0,0,0,0,0);
		if (!xd_command(cmdblk,PIO_MODE,0,0,0,XD_TIMEOUT * 8)) {
	 		xd_timer.expires = jiffies + XD_INIT_DISK_DELAY;
			add_timer(&xd_timer);
			sleep_on(&xdc_wait);

			init_drive(count);
			count++;

	 		xd_timer.expires = jiffies + XD_INIT_DISK_DELAY;
			add_timer(&xd_timer);
			sleep_on(&xdc_wait);
		}
	}
	return (count);
}

static void __init xd_manual_geo_set (u_char drive)
{
	xd_info[drive].heads = (u_char)(xd_geo[3 * drive + 1]);
	xd_info[drive].cylinders = (u_short)(xd_geo[3 * drive]);
	xd_info[drive].sectors = (u_char)(xd_geo[3 * drive + 2]);
}

static void __init xd_dtc_init_controller (unsigned int address)
{
	switch (address) {
		case 0x00000:
		case 0xC8000:	break;			/*initial: 0x320 */
		case 0xCA000:	xd_iobase = 0x324; 
		case 0xD0000:				/*5150CX*/
		case 0xD8000:	break;			/*5150CX & 5150XL*/
		default:        printk("xd_dtc_init_controller: unsupported BIOS address %06x\n",address);
				break;
	}
	xd_maxsectors = 0x01;		/* my card seems to have trouble doing multi-block transfers? */

	outb(0,XD_RESET);		/* reset the controller */
}


static void __init xd_dtc5150cx_init_drive (u_char drive)
{
	/* values from controller's BIOS - BIOS chip may be removed */
	static u_short geometry_table[][4] = {
		{0x200,8,0x200,0x100},
		{0x267,2,0x267,0x267},
		{0x264,4,0x264,0x80},
		{0x132,4,0x132,0x0},
		{0x132,2,0x80, 0x132},
		{0x177,8,0x177,0x0},
		{0x132,8,0x84, 0x0},
		{},  /* not used */
		{0x132,6,0x80, 0x100},
		{0x200,6,0x100,0x100},
		{0x264,2,0x264,0x80},
		{0x280,4,0x280,0x100},
		{0x2B9,3,0x2B9,0x2B9},
		{0x2B9,5,0x2B9,0x2B9},
		{0x280,6,0x280,0x100},
		{0x132,4,0x132,0x0}};
	u_char n;

	n = inb(XD_JUMPER);
	n = (drive ? n : (n >> 2)) & 0x33;
	n = (n | (n >> 2)) & 0x0F;
	if (xd_geo[3*drive])
		xd_manual_geo_set(drive);
	else
		if (n != 7) {	
			xd_info[drive].heads = (u_char)(geometry_table[n][1]);			/* heads */
			xd_info[drive].cylinders = geometry_table[n][0];	/* cylinders */
			xd_info[drive].sectors = 17;				/* sectors */
#if 0
			xd_info[drive].rwrite = geometry_table[n][2];	/* reduced write */
			xd_info[drive].precomp = geometry_table[n][3]		/* write precomp */
			xd_info[drive].ecc = 0x0B;				/* ecc length */
#endif /* 0 */
		}
		else {
			printk("xd%c: undetermined drive geometry\n",'a'+drive);
			return;
		}
	xd_info[drive].control = 5;				/* control byte */
	xd_setparam(CMD_DTCSETPARAM,drive,xd_info[drive].heads,xd_info[drive].cylinders,geometry_table[n][2],geometry_table[n][3],0x0B);
	xd_recalibrate(drive);
}

static void __init xd_dtc_init_drive (u_char drive)
{
	u_char cmdblk[6],buf[64];

	xd_build(cmdblk,CMD_DTCGETGEOM,drive,0,0,0,0,0);
	if (!xd_command(cmdblk,PIO_MODE,buf,0,0,XD_TIMEOUT * 2)) {
		xd_info[drive].heads = buf[0x0A];			/* heads */
		xd_info[drive].cylinders = ((u_short *) (buf))[0x04];	/* cylinders */
		xd_info[drive].sectors = 17;				/* sectors */
		if (xd_geo[3*drive])
			xd_manual_geo_set(drive);
#if 0
		xd_info[drive].rwrite = ((u_short *) (buf + 1))[0x05];	/* reduced write */
		xd_info[drive].precomp = ((u_short *) (buf + 1))[0x06];	/* write precomp */
		xd_info[drive].ecc = buf[0x0F];				/* ecc length */
#endif /* 0 */
		xd_info[drive].control = 0;				/* control byte */

		xd_setparam(CMD_DTCSETPARAM,drive,xd_info[drive].heads,xd_info[drive].cylinders,((u_short *) (buf + 1))[0x05],((u_short *) (buf + 1))[0x06],buf[0x0F]);
		xd_build(cmdblk,CMD_DTCSETSTEP,drive,0,0,0,0,7);
		if (xd_command(cmdblk,PIO_MODE,0,0,0,XD_TIMEOUT * 2))
			printk("xd_dtc_init_drive: error setting step rate for xd%c\n", 'a'+drive);
	}
	else
		printk("xd_dtc_init_drive: error reading geometry for xd%c\n", 'a'+drive);
}

static void __init xd_wd_init_controller (unsigned int address)
{
	switch (address) {
		case 0x00000:
		case 0xC8000:	break;			/*initial: 0x320 */
		case 0xCA000:	xd_iobase = 0x324; break;
		case 0xCC000:   xd_iobase = 0x328; break;
		case 0xCE000:   xd_iobase = 0x32C; break;
		case 0xD0000:	xd_iobase = 0x328; break; /* ? */
		case 0xD8000:	xd_iobase = 0x32C; break; /* ? */
		default:        printk("xd_wd_init_controller: unsupported BIOS address %06x\n",address);
				break;
	}