floppy.c

LINUX1.0内核源代码,学习LINUX编程的一定要看。

	output_byte(1);
}

static void floppy_ready(void)
{
	if (inb(FD_DIR) & 0x80) {
		changed_floppies |= 1<<current_drive;
		buffer_track = -1;
		if (keep_data[current_drive]) {
			if (keep_data[current_drive] > 0)
				keep_data[current_drive]--;
		} else {
			if (ftd_msg[current_drive] && current_type[current_drive] != NULL)
				printk("Disk type is undefined after disk "
				    "change in fd%d\n",current_drive);
			current_type[current_drive] = NULL;
			floppy_sizes[current_drive] = MAX_DISK_SIZE;
		}
/* Forcing the drive to seek makes the "media changed" condition go away.
 * There should be a cleaner solution for that ...
 */
		if (!reset && !recalibrate) {
			if (current_track && current_track != NO_TRACK)
				do_floppy = shake_zero;
			else
				do_floppy = shake_one;
			output_byte(FD_RECALIBRATE);
			output_byte(head<<2 | current_drive);
			return;
		}
	}
	if (reset) {
		reset_floppy();
		return;
	}
	if (recalibrate) {
		recalibrate_floppy();
		return;
	}
	transfer();
}

static void setup_format_params(void)
{
    unsigned char *here = (unsigned char *) tmp_floppy_area;
    int count,head_shift,track_shift,total_shift;

    /* allow for about 30ms for data transport per track */
    head_shift  = floppy->sect / 6;
    /* a ``cylinder'' is two tracks plus a little stepping time */
    track_shift = 2 * head_shift + 1; 
    /* count backwards */
    total_shift = floppy->sect - 
	((track_shift * track + head_shift * head) % floppy->sect);

    /* XXX: should do a check to see this fits in tmp_floppy_area!! */
    for (count = 0; count < floppy->sect; count++) {
	*here++ = track;
	*here++ = head;
	*here++ = 1 + (( count + total_shift ) % floppy->sect);
	*here++ = 2; /* 512 bytes */
    }
}

static void redo_fd_request(void)
{
	unsigned int block;
	char * buffer_area;
	int device;

	if (CURRENT && CURRENT->dev < 0) return;

repeat:
	if (format_status == FORMAT_WAIT)
		format_status = FORMAT_BUSY;
	if (format_status != FORMAT_BUSY) {
		if (!CURRENT) {
			if (!fdc_busy)
				printk("FDC access conflict!");
			fdc_busy = 0;
			wake_up(&fdc_wait);
			CLEAR_INTR;
			return;
		}
		if (MAJOR(CURRENT->dev) != MAJOR_NR)
			panic(DEVICE_NAME ": request list destroyed"); \
		if (CURRENT->bh) {
			if (!CURRENT->bh->b_lock)
				panic(DEVICE_NAME ": block not locked");
		}
	}
	seek = 0;
	probing = 0;
	device = MINOR(CURRENT_DEVICE);
	if (device > 3)
		floppy = (device >> 2) + floppy_type;
	else { /* Auto-detection */
		floppy = current_type[device & 3];
		if (!floppy) {
			probing = 1;
			floppy = base_type[device & 3];
			if (!floppy) {
				request_done(0);
				goto repeat;
			}
			if (CURRENT_ERRORS & 1)
				floppy++;
		}
	}
	if (format_status != FORMAT_BUSY) {
		if (current_drive != CURRENT_DEV) {
			current_track = NO_TRACK;
			current_drive = CURRENT_DEV;
		}
		block = CURRENT->sector;
		if (block+2 > floppy->size) {
			request_done(0);
			goto repeat;
		}
		sector = block % floppy->sect;
		block /= floppy->sect;
		head = block % floppy->head;
		track = block / floppy->head;
		seek_track = track << floppy->stretch;
		if (CURRENT->cmd == READ)
			command = FD_READ;
		else if (CURRENT->cmd == WRITE)
			command = FD_WRITE;
		else {
			printk("do_fd_request: unknown command\n");
			request_done(0);
			goto repeat;
		}
	} else {
		if (current_drive != (format_req.device & 3))
			current_track = NO_TRACK;
		current_drive = format_req.device & 3;
		if (((unsigned) format_req.track) >= floppy->track ||
		    (format_req.head & 0xfffe) || probing) {
			request_done(0);
			goto repeat;
		}
		head = format_req.head;
		track = format_req.track;
		seek_track = track << floppy->stretch;
		if (seek_track == buffer_track) buffer_track = -1;
		command = FD_FORMAT;
		setup_format_params();
	}
	timer_table[FLOPPY_TIMER].expires = jiffies+10*HZ;
	timer_active |= 1 << FLOPPY_TIMER;
	if ((seek_track == buffer_track) &&
	 (current_drive == buffer_drive)) {
		buffer_area = floppy_track_buffer +
			((sector + head*floppy->sect)<<9);
		if (command == FD_READ) {
			copy_buffer(buffer_area,CURRENT->buffer);
			request_done(1);
			goto repeat;
		} else if (command == FD_WRITE)
			copy_buffer(CURRENT->buffer,buffer_area);
	}
	if (seek_track != current_track)
		seek = 1;
	sector++;
	del_timer(motor_off_timer + current_drive);
	floppy_on(current_drive);
}

void do_fd_request(void)
{
	cli();
	while (fdc_busy) sleep_on(&fdc_wait);
	fdc_busy = 1;
	sti();
	redo_fd_request();
}

static int fd_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
    unsigned long param)
{
	int i,drive,cnt,okay;
	struct floppy_struct *this_floppy;

	switch (cmd) {
		RO_IOCTLS(inode->i_rdev,param);
	}
	drive = MINOR(inode->i_rdev);
	switch (cmd) {
		case FDFMTBEG:
			if (!suser())
				return -EPERM;
			return 0;
		case FDFMTEND:
			if (!suser())
				return -EPERM;
			cli();
			fake_change |= 1 << (drive & 3);
			sti();
			drive &= 3;
			cmd = FDCLRPRM;
			break;
		case FDGETPRM:
			if (drive > 3) this_floppy = &floppy_type[drive >> 2];
			else if ((this_floppy = current_type[drive & 3]) == NULL)
				    return -ENODEV;
			i = verify_area(VERIFY_WRITE,(void *) param,sizeof(struct floppy_struct));
			if (i)
				return i;
			for (cnt = 0; cnt < sizeof(struct floppy_struct); cnt++)
				put_fs_byte(((char *) this_floppy)[cnt],
				    (char *) param+cnt);
			return 0;
		case FDFMTTRK:
			if (!suser())
				return -EPERM;
			if (fd_ref[drive & 3] != 1)
				return -EBUSY;
			cli();
			while (format_status != FORMAT_NONE)
				sleep_on(&format_done);
			for (cnt = 0; cnt < sizeof(struct format_descr); cnt++)
				((char *) &format_req)[cnt] = get_fs_byte(
				    (char *) param+cnt);
			format_req.device = drive;
			format_status = FORMAT_WAIT;
			format_errors = 0;
			while (format_status != FORMAT_OKAY && format_status !=
			    FORMAT_ERROR) {
				if (fdc_busy) sleep_on(&fdc_wait);
				else {
					fdc_busy = 1;
					redo_fd_request();
				}
			}
			while (format_status != FORMAT_OKAY && format_status !=
			    FORMAT_ERROR)
				sleep_on(&format_done);
			sti();
			okay = format_status == FORMAT_OKAY;
			format_status = FORMAT_NONE;
			floppy_off(drive & 3);
			wake_up(&format_done);
			return okay ? 0 : -EIO;
		case FDFLUSH:
			if (!permission(inode, 2))
				return -EPERM;
			cli();
			fake_change |= 1 << (drive & 3);
			sti();
			check_disk_change(inode->i_rdev);
			return 0;
 	}
	if (!suser())
		return -EPERM;
	if (drive < 0 || drive > 3)
		return -EINVAL;
	switch (cmd) {
		case FDCLRPRM:
			current_type[drive] = NULL;
			floppy_sizes[drive] = MAX_DISK_SIZE;
			keep_data[drive] = 0;
			break;
		case FDSETPRM:
		case FDDEFPRM:
			memcpy_fromfs(user_params+drive,
				(void *) param,
				sizeof(struct floppy_struct));
			current_type[drive] = &user_params[drive];
			floppy_sizes[drive] = user_params[drive].size >> 1;
			if (cmd == FDDEFPRM)
				keep_data[drive] = -1;
			else {
				cli();
				while (fdc_busy) sleep_on(&fdc_wait);
				fdc_busy = 1;
				sti();
				outb_p((current_DOR & 0xfc) | drive |
				    (0x10 << drive),FD_DOR);
				for (cnt = 0; cnt < 1000; cnt++) __asm__("nop");
				if (inb(FD_DIR) & 0x80)
					keep_data[drive] = 1;
				else
					keep_data[drive] = 0;
				outb_p(current_DOR,FD_DOR);
				fdc_busy = 0;
				wake_up(&fdc_wait);
			}
			break;
		case FDMSGON:
			ftd_msg[drive] = 1;
			break;
		case FDMSGOFF:
			ftd_msg[drive] = 0;
			break;
		case FDSETEMSGTRESH:
			min_report_error_cnt[drive] = (unsigned short) (param & 0x0f);
			break;
		default:
			return -EINVAL;
	}
	return 0;
}

#define CMOS_READ(addr) ({ \
outb_p(addr,0x70); \
inb_p(0x71); \
})

static struct floppy_struct *find_base(int drive,int code)
{
	struct floppy_struct *base;

	if (code > 0 && code < 5) {
		base = &floppy_types[(code-1)*2];
		printk("fd%d is %s",drive,base->name);
		return base;
	}
	printk("fd%d is unknown type %d",drive,code);
	return NULL;
}

static void config_types(void)
{
	printk("Floppy drive(s): ");
	base_type[0] = find_base(0,(CMOS_READ(0x10) >> 4) & 15);
	if (((CMOS_READ(0x14) >> 6) & 1) == 0)
		base_type[1] = NULL;
	else {
		printk(", ");
		base_type[1] = find_base(1,CMOS_READ(0x10) & 15);
	}
	base_type[2] = base_type[3] = NULL;
	printk("\n");
}

/*
 * floppy_open check for aliasing (/dev/fd0 can be the same as
 * /dev/PS0 etc), and disallows simultaneous access to the same
 * drive with different device numbers.
 */
static int floppy_open(struct inode * inode, struct file * filp)
{
	int drive;
	int old_dev;

	drive = inode->i_rdev & 3;
	old_dev = fd_device[drive];
	if (fd_ref[drive])
		if (old_dev != inode->i_rdev)
			return -EBUSY;
	fd_ref[drive]++;
	fd_device[drive] = inode->i_rdev;
	buffer_drive = buffer_track = -1;
	if (old_dev && old_dev != inode->i_rdev)
		invalidate_buffers(old_dev);
	if (filp && filp->f_mode)
		check_disk_change(inode->i_rdev);
	return 0;
}

static void floppy_release(struct inode * inode, struct file * filp)
{
	sync_dev(inode->i_rdev);
	if (!fd_ref[inode->i_rdev & 3]--) {
		printk("floppy_release with fd_ref == 0");
		fd_ref[inode->i_rdev & 3] = 0;
	}
}

static struct file_operations floppy_fops = {
	NULL,			/* lseek - default */
	block_read,		/* read - general block-dev read */
	block_write,		/* write - general block-dev write */
	NULL,			/* readdir - bad */
	NULL,			/* select */
	fd_ioctl,		/* ioctl */
	NULL,			/* mmap */
	floppy_open,		/* open */
	floppy_release,		/* release */
	block_fsync		/* fsync */
};


/*
 * The version command is not supposed to generate an interrupt, but
 * my FDC does, except when booting in SVGA screen mode.
 * When it does generate an interrupt, it doesn't return any status bytes.
 * It appears to have something to do with the version command...
 *
 * This should never be called, because of the reset after the version check.
 */
static void ignore_interrupt(void)
{
	printk(DEVICE_NAME ": weird interrupt ignored (%d)\n", result());
	reset = 1;
	CLEAR_INTR;	/* ignore only once */
}


static void floppy_interrupt(int unused)
{
	void (*handler)(void) = DEVICE_INTR;

	DEVICE_INTR = NULL;
	if (!handler)
		handler = unexpected_floppy_interrupt;
	handler();
}

/*
 * This is the floppy IRQ description. The SA_INTERRUPT in sa_flags
 * means we run the IRQ-handler with interrupts disabled.
 */
static struct sigaction floppy_sigaction = {
	floppy_interrupt,
	0,
	SA_INTERRUPT,
	NULL
};

void floppy_init(void)
{
	outb(current_DOR,FD_DOR);
	if (register_blkdev(MAJOR_NR,"fd",&floppy_fops)) {
		printk("Unable to get major %d for floppy\n",MAJOR_NR);
		return;
	}
	blk_size[MAJOR_NR] = floppy_sizes;
	blk_dev[MAJOR_NR].request_fn = DEVICE_REQUEST;
	timer_table[FLOPPY_TIMER].fn = floppy_shutdown;
	timer_active &= ~(1 << FLOPPY_TIMER);
	config_types();
	if (irqaction(FLOPPY_IRQ,&floppy_sigaction))
		printk("Unable to grab IRQ%d for the floppy driver\n", FLOPPY_IRQ);
	if (request_dma(FLOPPY_DMA))
		printk("Unable to grab DMA%d for the floppy driver\n", FLOPPY_DMA);
	/* Try to determine the floppy controller type */
	DEVICE_INTR = ignore_interrupt;	/* don't ask ... */
	output_byte(FD_VERSION);	/* get FDC version code */
	if (result() != 1) {
		printk(DEVICE_NAME ": FDC failed to return version byte\n");
		fdc_version = FDC_TYPE_STD;
	} else
		fdc_version = reply_buffer[0];
	if (fdc_version != FDC_TYPE_STD) 
		printk(DEVICE_NAME ": FDC version 0x%x\n", fdc_version);
#ifndef FDC_FIFO_UNTESTED
	fdc_version = FDC_TYPE_STD;	/* force std fdc type; can't test other. */
#endif

	/* Not all FDCs seem to be able to handle the version command
	 * properly, so force a reset for the standard FDC clones,
	 * to avoid interrupt garbage.
	 */

	if (fdc_version == FDC_TYPE_STD) {
		initial_reset_flag = 1;
		reset_floppy();
	}
}