fdc-isr.c

linux-2.6.15.6

/*
 *      Copyright (C) 1994-1996 Bas Laarhoven,
 *                (C) 1996-1997 Claus-Justus Heine.

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2, or (at your option)
 any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; see the file COPYING.  If not, write to
 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

 *
 * $Source: /homes/cvs/ftape-stacked/ftape/lowlevel/fdc-isr.c,v $
 * $Revision: 1.9 $
 * $Date: 1997/10/17 23:01:53 $
 *
 *      This file contains the interrupt service routine and
 *      associated code for the QIC-40/80/3010/3020 floppy-tape driver
 *      "ftape" for Linux.
 */

#include <asm/io.h>
#include <asm/dma.h>

#define volatile		/* */

#include <linux/ftape.h>
#include <linux/qic117.h>
#include "../lowlevel/ftape-tracing.h"
#include "../lowlevel/fdc-isr.h"
#include "../lowlevel/fdc-io.h"
#include "../lowlevel/ftape-ctl.h"
#include "../lowlevel/ftape-rw.h"
#include "../lowlevel/ftape-io.h"
#include "../lowlevel/ftape-calibr.h"
#include "../lowlevel/ftape-bsm.h"

/*      Global vars.
 */
volatile int ft_expected_stray_interrupts;
volatile int ft_interrupt_seen;
volatile int ft_seek_completed;
volatile int ft_hide_interrupt;
/*      Local vars.
 */
typedef enum {
	no_error = 0, id_am_error = 0x01, id_crc_error = 0x02,
	data_am_error = 0x04, data_crc_error = 0x08,
	no_data_error = 0x10, overrun_error = 0x20,
} error_cause;
static int stop_read_ahead;


static void print_error_cause(int cause)
{
	TRACE_FUN(ft_t_any);

	switch (cause) {
	case no_data_error:
		TRACE(ft_t_noise, "no data error");
		break;
	case id_am_error:
		TRACE(ft_t_noise, "id am error");
		break;
	case id_crc_error:
		TRACE(ft_t_noise, "id crc error");
		break;
	case data_am_error:
		TRACE(ft_t_noise, "data am error");
		break;
	case data_crc_error:
		TRACE(ft_t_noise, "data crc error");
		break;
	case overrun_error:
		TRACE(ft_t_noise, "overrun error");
		break;
	default:;
	}
	TRACE_EXIT;
}

static char *fdc_mode_txt(fdc_mode_enum mode)
{
	switch (mode) {
	case fdc_idle:
		return "fdc_idle";
	case fdc_reading_data:
		return "fdc_reading_data";
	case fdc_seeking:
		return "fdc_seeking";
	case fdc_writing_data:
		return "fdc_writing_data";
	case fdc_reading_id:
		return "fdc_reading_id";
	case fdc_recalibrating:
		return "fdc_recalibrating";
	case fdc_formatting:
		return "fdc_formatting";
	case fdc_verifying:
		return "fdc_verifying";
	default:
		return "unknown";
	}
}

static inline error_cause decode_irq_cause(fdc_mode_enum mode, __u8 st[])
{
	error_cause cause = no_error;
	TRACE_FUN(ft_t_any);

	/*  Valid st[], decode cause of interrupt.
	 */
	switch (st[0] & ST0_INT_MASK) {
	case FDC_INT_NORMAL:
		TRACE(ft_t_fdc_dma,"normal completion: %s",fdc_mode_txt(mode));
		break;
	case FDC_INT_ABNORMAL:
		TRACE(ft_t_flow, "abnormal completion %s", fdc_mode_txt(mode));
		TRACE(ft_t_fdc_dma, "ST0: 0x%02x, ST1: 0x%02x, ST2: 0x%02x",
		      st[0], st[1], st[2]);
		TRACE(ft_t_fdc_dma,
		      "C: 0x%02x, H: 0x%02x, R: 0x%02x, N: 0x%02x",
		      st[3], st[4], st[5], st[6]);
		if (st[1] & 0x01) {
			if (st[2] & 0x01) {
				cause = data_am_error;
			} else {
				cause = id_am_error;
			}
		} else if (st[1] & 0x20) {
			if (st[2] & 0x20) {
				cause = data_crc_error;
			} else {
				cause = id_crc_error;
			}
		} else if (st[1] & 0x04) {
			cause = no_data_error;
		} else if (st[1] & 0x10) {
			cause = overrun_error;
		}
		print_error_cause(cause);
		break;
	case FDC_INT_INVALID:
		TRACE(ft_t_flow, "invalid completion %s", fdc_mode_txt(mode));
		break;
	case FDC_INT_READYCH:
		if (st[0] & ST0_SEEK_END) {
			TRACE(ft_t_flow, "drive poll completed");
		} else {
			TRACE(ft_t_flow, "ready change %s",fdc_mode_txt(mode));
		}
		break;
	default:
		break;
	}
	TRACE_EXIT cause;
}

static void update_history(error_cause cause)
{
	switch (cause) {
	case id_am_error:
		ft_history.id_am_errors++;
		break;
	case id_crc_error:
		ft_history.id_crc_errors++;
		break;
	case data_am_error:
		ft_history.data_am_errors++;
		break;
	case data_crc_error:
		ft_history.data_crc_errors++;
		break;
	case overrun_error:
		ft_history.overrun_errors++;
		break;
	case no_data_error:
		ft_history.no_data_errors++;
		break;
	default:;
	}
}

static void skip_bad_sector(buffer_struct * buff)
{
	TRACE_FUN(ft_t_any);

	/*  Mark sector as soft error and skip it
	 */
	if (buff->remaining > 0) {
		++buff->sector_offset;
		++buff->data_offset;
		--buff->remaining;
		buff->ptr += FT_SECTOR_SIZE;
		buff->bad_sector_map >>= 1;
	} else {
		/*  Hey, what is this????????????? C code: if we shift 
		 *  more than 31 bits, we get no shift. That's bad!!!!!!
		 */
		++buff->sector_offset;	/* hack for error maps */
		TRACE(ft_t_warn, "skipping last sector in segment");
	}
	TRACE_EXIT;
}

static void update_error_maps(buffer_struct * buff, unsigned int error_offset)
{
	int hard = 0;
	TRACE_FUN(ft_t_any);

	if (buff->retry < FT_SOFT_RETRIES) {
		buff->soft_error_map |= (1 << error_offset);
	} else {
		buff->hard_error_map |= (1 << error_offset);
		buff->soft_error_map &= ~buff->hard_error_map;
		buff->retry = -1;  /* will be set to 0 in setup_segment */
		hard = 1;
	}
	TRACE(ft_t_noise, "sector %d : %s error\n"
	      KERN_INFO "hard map: 0x%08lx\n"
	      KERN_INFO "soft map: 0x%08lx",
	      FT_SECTOR(error_offset), hard ? "hard" : "soft",
	      (long) buff->hard_error_map, (long) buff->soft_error_map);
	TRACE_EXIT;
}

static void print_progress(buffer_struct *buff, error_cause cause)
{
	TRACE_FUN(ft_t_any);

	switch (cause) {
	case no_error: 
		TRACE(ft_t_flow,"%d Sector(s) transferred", buff->sector_count);
		break;
	case no_data_error:
		TRACE(ft_t_flow, "Sector %d not found",
		      FT_SECTOR(buff->sector_offset));
		break;
	case overrun_error:
		/*  got an overrun error on the first byte, must be a
		 *  hardware problem
		 */
		TRACE(ft_t_bug,
		      "Unexpected error: failing DMA or FDC controller ?");
		break;
	case data_crc_error:
		TRACE(ft_t_flow, "Error in sector %d",
		      FT_SECTOR(buff->sector_offset - 1));
		break;
	case id_crc_error:
	case id_am_error:
	case data_am_error:
		TRACE(ft_t_flow, "Error in sector %d",
		      FT_SECTOR(buff->sector_offset));
		break;
	default:
		TRACE(ft_t_flow, "Unexpected error at sector %d",
		      FT_SECTOR(buff->sector_offset));
		break;
	}
	TRACE_EXIT;
}

/*
 *  Error cause:   Amount xferred:  Action:
 *
 *  id_am_error         0           mark bad and skip
 *  id_crc_error        0           mark bad and skip
 *  data_am_error       0           mark bad and skip
 *  data_crc_error    % 1024        mark bad and skip
 *  no_data_error       0           retry on write
 *                                  mark bad and skip on read
 *  overrun_error  [ 0..all-1 ]     mark bad and skip
 *  no_error           all          continue
 */

/*  the arg `sector' is returned by the fdc and tells us at which sector we
 *  are positioned at (relative to starting sector of segment)
 */
static void determine_verify_progress(buffer_struct *buff,
				      error_cause cause,
				      __u8 sector)
{
	TRACE_FUN(ft_t_any);

	if (cause == no_error && sector == 1) {
		buff->sector_offset = FT_SECTORS_PER_SEGMENT;
		buff->remaining     = 0;
		if (TRACE_LEVEL >= ft_t_flow) {
			print_progress(buff, cause);
		}
	} else {
		buff->sector_offset = sector - buff->sect;
		buff->remaining = FT_SECTORS_PER_SEGMENT - buff->sector_offset;
		TRACE(ft_t_noise, "%ssector offset: 0x%04x", 
		      (cause == no_error) ? "unexpected " : "",
		      buff->sector_offset);
		switch (cause) {
		case overrun_error:
			break;
#if 0
		case no_data_error:
			buff->retry = FT_SOFT_RETRIES;
			if (buff->hard_error_map    &&
			    buff->sector_offset > 1 &&
			    (buff->hard_error_map & 
			     (1 << (buff->sector_offset-2)))) {
				buff->retry --;
			}
			break;
#endif
		default:
			buff->retry = FT_SOFT_RETRIES;
			break;
		}
		if (TRACE_LEVEL >= ft_t_flow) {
			print_progress(buff, cause);
		}
		/*  Sector_offset points to the problem area Now adjust
		 *  sector_offset so it always points one past he failing
		 *  sector. I.e. skip the bad sector.
		 */
		++buff->sector_offset;
		--buff->remaining;
		update_error_maps(buff, buff->sector_offset - 1);
	}
	TRACE_EXIT;
}

static void determine_progress(buffer_struct *buff,
			       error_cause cause,
			       __u8 sector)
{
	unsigned int dma_residue;
	TRACE_FUN(ft_t_any);

	/*  Using less preferred order of disable_dma and
	 *  get_dma_residue because this seems to fail on at least one
	 *  system if reversed!
	 */
	dma_residue = get_dma_residue(fdc.dma);
	disable_dma(fdc.dma);
	if (cause != no_error || dma_residue != 0) {
		TRACE(ft_t_noise, "%sDMA residue: 0x%04x", 
		      (cause == no_error) ? "unexpected " : "",
		      dma_residue);
		/* adjust to actual value: */
		if (dma_residue == 0) {
			/* this happens sometimes with overrun errors.
			 * I don't know whether we could ignore the
			 * overrun error. Play save.
			 */
			buff->sector_count --;
		} else {
			buff->sector_count -= ((dma_residue + 
						(FT_SECTOR_SIZE - 1)) /
					       FT_SECTOR_SIZE);
		}
	}
	/*  Update var's influenced by the DMA operation.
	 */
	if (buff->sector_count > 0) {
		buff->sector_offset   += buff->sector_count;
		buff->data_offset     += buff->sector_count;
		buff->ptr             += (buff->sector_count *
					  FT_SECTOR_SIZE);
		buff->remaining       -= buff->sector_count;
		buff->bad_sector_map >>= buff->sector_count;
	}
	if (TRACE_LEVEL >= ft_t_flow) {
		print_progress(buff, cause);
	}
	if (cause != no_error) {
		if (buff->remaining == 0) {
			TRACE(ft_t_warn, "foo?\n"
			      KERN_INFO "count : %d\n"
			      KERN_INFO "offset: %d\n"
			      KERN_INFO "soft  : %08x\n"
			      KERN_INFO "hard  : %08x",
			      buff->sector_count,
			      buff->sector_offset,
			      buff->soft_error_map,
			      buff->hard_error_map);
		}
		/*  Sector_offset points to the problem area, except if we got
		 *  a data_crc_error. In that case it points one past the
		 *  failing sector.
		 *
		 *  Now adjust sector_offset so it always points one past he
		 *  failing sector. I.e. skip the bad sector.  
		 */
		if (cause != data_crc_error) {
			skip_bad_sector(buff);
		}
		update_error_maps(buff, buff->sector_offset - 1);
	}
	TRACE_EXIT;
}

static int calc_steps(int cmd)
{
	if (ftape_current_cylinder > cmd) {
		return ftape_current_cylinder - cmd;
	} else {
		return ftape_current_cylinder + cmd;
	}
}

static void pause_tape(int retry, int mode)
{
	int result;
	__u8 out[3] = {FDC_SEEK, ft_drive_sel, 0};
	TRACE_FUN(ft_t_any);

	/*  We'll use a raw seek command to get the tape to rewind and
	 *  stop for a retry.
	 */
	++ft_history.rewinds;
	if (qic117_cmds[ftape_current_command].non_intr) {
		TRACE(ft_t_warn, "motion command may be issued too soon");
	}
	if (retry && (mode == fdc_reading_data ||
		      mode == fdc_reading_id   ||
		      mode == fdc_verifying)) {
		ftape_current_command = QIC_MICRO_STEP_PAUSE;
		ftape_might_be_off_track = 1;
	} else {
		ftape_current_command = QIC_PAUSE;
	}
	out[2] = calc_steps(ftape_current_command);
	result = fdc_command(out, 3); /* issue QIC_117 command */
	ftape_current_cylinder = out[ 2];
	if (result < 0) {
		TRACE(ft_t_noise, "qic-pause failed, status = %d", result);
	} else {
		ft_location.known  = 0;
		ft_runner_status   = idle;
		ft_hide_interrupt     = 1;
		ftape_tape_running = 0;
	}
	TRACE_EXIT;
}

static void continue_xfer(buffer_struct *buff,
			  fdc_mode_enum mode, 
			  unsigned int skip)
{
	int write = 0;
 	TRACE_FUN(ft_t_any);

	if (mode == fdc_writing_data || mode == fdc_deleting) {
		write = 1;
	}
	/*  This part can be removed if it never happens
	 */
	if (skip > 0 &&
	    (ft_runner_status != running ||
	     (write && (buff->status != writing)) ||
	     (!write && (buff->status != reading && 
			 buff->status != verifying)))) {
		TRACE(ft_t_err, "unexpected runner/buffer state %d/%d",
		      ft_runner_status, buff->status);
		buff->status = error;
		/* finish this buffer: */
		(void)ftape_next_buffer(ft_queue_head);
		ft_runner_status = aborting;
		fdc_mode         = fdc_idle;