floppy.c

GNU Mach 微内核源代码, 基于美国卡内基美隆大学的 Mach 研究项目

static void floppy_enable_hlt(void)
{
	unsigned long flags;

	INT_OFF;
	if (hlt_disabled){
		hlt_disabled=0;
#ifdef HAVE_DISABLE_HLT
		enable_hlt();
#endif
	}
	INT_ON;
}


static void setup_DMA(void)
{
	unsigned long flags;

#ifdef FLOPPY_SANITY_CHECK
	if (raw_cmd->length == 0){
		int i;

		printk("zero dma transfer size:");
		for (i=0; i < raw_cmd->cmd_count; i++)
			printk("%x,", raw_cmd->cmd[i]);
		printk("\n");
		cont->done(0);
		FDCS->reset = 1;
		return;
	}
	if ((long) raw_cmd->kernel_data % 512){
		printk("non aligned address: %p\n", raw_cmd->kernel_data);
		cont->done(0);
		FDCS->reset=1;
		return;
	}
	if (CROSS_64KB(raw_cmd->kernel_data, raw_cmd->length)) {
		printk("DMA crossing 64-K boundary %p-%p\n",
		       raw_cmd->kernel_data,
		       raw_cmd->kernel_data + raw_cmd->length);
		cont->done(0);
		FDCS->reset=1;
		return;
	}
#endif
	INT_OFF;
	fd_disable_dma();
	fd_clear_dma_ff();
	fd_cacheflush(raw_cmd->kernel_data, raw_cmd->length);
	fd_set_dma_mode((raw_cmd->flags & FD_RAW_READ)?
			DMA_MODE_READ : DMA_MODE_WRITE);
	fd_set_dma_addr(virt_to_bus(raw_cmd->kernel_data));
	fd_set_dma_count(raw_cmd->length);
	virtual_dma_port = FDCS->address;
	fd_enable_dma();
	INT_ON;
	floppy_disable_hlt();
}

void show_floppy(void);

/* waits until the fdc becomes ready */
static int wait_til_ready(void)
{
	int counter, status;
	if(FDCS->reset)
		return -1;
	for (counter = 0; counter < 10000; counter++) {
		status = fd_inb(FD_STATUS);		
		if (status & STATUS_READY)
			return status;
	}
	if (!initialising) {
		DPRINT("Getstatus times out (%x) on fdc %d\n",
			status, fdc);
		show_floppy();
	}
	FDCS->reset = 1;
	return -1;
}

/* sends a command byte to the fdc */
static int output_byte(char byte)
{
	int status;

	if ((status = wait_til_ready()) < 0)
		return -1;
	if ((status & (STATUS_READY|STATUS_DIR|STATUS_DMA)) == STATUS_READY){
		fd_outb(byte,FD_DATA);
#ifdef FLOPPY_SANITY_CHECK
		output_log[output_log_pos].data = byte;
		output_log[output_log_pos].status = status;
		output_log[output_log_pos].jiffies = jiffies;
		output_log_pos = (output_log_pos + 1) % OLOGSIZE;
#endif
		return 0;
	}
	FDCS->reset = 1;
	if (!initialising) {
		DPRINT("Unable to send byte %x to FDC. Fdc=%x Status=%x\n",
		       byte, fdc, status);
		show_floppy();
	}
	return -1;
}
#define LAST_OUT(x) if (output_byte(x)<0){ reset_fdc();return;}

/* gets the response from the fdc */
static int result(void)
{
	int i, status;

	for(i=0; i < MAX_REPLIES; i++) {
		if ((status = wait_til_ready()) < 0)
			break;
		status &= STATUS_DIR|STATUS_READY|STATUS_BUSY|STATUS_DMA;
		if ((status & ~STATUS_BUSY) == STATUS_READY){
#ifdef FLOPPY_SANITY_CHECK
			resultjiffies = jiffies;
			resultsize = i;
#endif
			return i;
		}
		if (status == (STATUS_DIR|STATUS_READY|STATUS_BUSY))
			reply_buffer[i] = fd_inb(FD_DATA);
		else
			break;
	}
	if(!initialising) {
		DPRINT("get result error. Fdc=%d Last status=%x Read bytes=%d\n",
		       fdc, status, i);
		show_floppy();
	}
	FDCS->reset = 1;
	return -1;
}

#define MORE_OUTPUT -2
/* does the fdc need more output? */
static int need_more_output(void)
{
	int status;
	if( (status = wait_til_ready()) < 0)
		return -1;
	if ((status & (STATUS_READY|STATUS_DIR|STATUS_DMA)) == STATUS_READY)
		return MORE_OUTPUT;
	return result();
}

/* Set perpendicular mode as required, based on data rate, if supported.
 * 82077 Now tested. 1Mbps data rate only possible with 82077-1.
 */
static inline void perpendicular_mode(void)
{
	unsigned char perp_mode;

	if (raw_cmd->rate & 0x40){
		switch(raw_cmd->rate & 3){
			case 0:
				perp_mode=2;
				break;
			case 3:
				perp_mode=3;
				break;
			default:
				DPRINT("Invalid data rate for perpendicular mode!\n");
				cont->done(0);
				FDCS->reset = 1; /* convenient way to return to
						  * redo without to much hassle (deep
						  * stack et al. */
				return;
		}
	} else
		perp_mode = 0;

	if (FDCS->perp_mode == perp_mode)
		return;
	if (FDCS->version >= FDC_82077_ORIG) {
		output_byte(FD_PERPENDICULAR);
		output_byte(perp_mode);
		FDCS->perp_mode = perp_mode;
	} else if (perp_mode) {
		DPRINT("perpendicular mode not supported by this FDC.\n");
	}
} /* perpendicular_mode */

static int fifo_depth = 0xa;
static int no_fifo = 0;

static int fdc_configure(void)
{
	/* Turn on FIFO */
	output_byte(FD_CONFIGURE);
	if(need_more_output() != MORE_OUTPUT)
		return 0;
	output_byte(0);
	output_byte(0x10 | (no_fifo & 0x20) | (fifo_depth & 0xf));
	output_byte(0);	/* pre-compensation from track 
			   0 upwards */
	return 1;
}	

#define NOMINAL_DTR 500

/* Issue a "SPECIFY" command to set the step rate time, head unload time,
 * head load time, and DMA disable flag to values needed by floppy.
 *
 * The value "dtr" is the data transfer rate in Kbps.  It is needed
 * to account for the data rate-based scaling done by the 82072 and 82077
 * FDC types.  This parameter is ignored for other types of FDCs (i.e.
 * 8272a).
 *
 * Note that changing the data transfer rate has a (probably deleterious)
 * effect on the parameters subject to scaling for 82072/82077 FDCs, so
 * fdc_specify is called again after each data transfer rate
 * change.
 *
 * srt: 1000 to 16000 in microseconds
 * hut: 16 to 240 milliseconds
 * hlt: 2 to 254 milliseconds
 *
 * These values are rounded up to the next highest available delay time.
 */
static void fdc_specify(void)
{
	unsigned char spec1, spec2;
	int srt, hlt, hut;
	unsigned long dtr = NOMINAL_DTR;
	unsigned long scale_dtr = NOMINAL_DTR;
	int hlt_max_code = 0x7f;
	int hut_max_code = 0xf;

	if (FDCS->need_configure && FDCS->version >= FDC_82072A) {
		fdc_configure();
		FDCS->need_configure = 0;
		/*DPRINT("FIFO enabled\n");*/
	}

	switch (raw_cmd->rate & 0x03) {
		case 3:
			dtr = 1000;
			break;
		case 1:
			dtr = 300;
			if (FDCS->version >= FDC_82078) {
				/* chose the default rate table, not the one
				 * where 1 = 2 Mbps */
				output_byte(FD_DRIVESPEC);
				if(need_more_output() == MORE_OUTPUT) {
					output_byte(UNIT(current_drive));
					output_byte(0xc0);
				}
			}
			break;
		case 2:
			dtr = 250;
			break;
	}

	if (FDCS->version >= FDC_82072) {
		scale_dtr = dtr;
		hlt_max_code = 0x00; /* 0==256msec*dtr0/dtr (not linear!) */
		hut_max_code = 0x0; /* 0==256msec*dtr0/dtr (not linear!) */
	}

	/* Convert step rate from microseconds to milliseconds and 4 bits */
	srt = 16 - (DP->srt*scale_dtr/1000 + NOMINAL_DTR - 1)/NOMINAL_DTR;
	SUPBOUND(srt, 0xf);
	INFBOUND(srt, 0);

	hlt = (DP->hlt*scale_dtr/2 + NOMINAL_DTR - 1)/NOMINAL_DTR;
	if (hlt < 0x01)
		hlt = 0x01;
	else if (hlt > 0x7f)
		hlt = hlt_max_code;

	hut = (DP->hut*scale_dtr/16 + NOMINAL_DTR - 1)/NOMINAL_DTR;
	if (hut < 0x1)
		hut = 0x1;
	else if (hut > 0xf)
		hut = hut_max_code;

	spec1 = (srt << 4) | hut;
	spec2 = (hlt << 1) | (use_virtual_dma & 1);

	/* If these parameters did not change, just return with success */
	if (FDCS->spec1 != spec1 || FDCS->spec2 != spec2) {
		/* Go ahead and set spec1 and spec2 */
		output_byte(FD_SPECIFY);
		output_byte(FDCS->spec1 = spec1);
		output_byte(FDCS->spec2 = spec2);
	}
} /* fdc_specify */

/* Set the FDC's data transfer rate on behalf of the specified drive.
 * NOTE: with 82072/82077 FDCs, changing the data rate requires a reissue
 * of the specify command (i.e. using the fdc_specify function).
 */
static int fdc_dtr(void)
{
	/* If data rate not already set to desired value, set it. */
	if ((raw_cmd->rate & 3) == FDCS->dtr)
		return 0;

	/* Set dtr */
	fd_outb(raw_cmd->rate & 3, FD_DCR);

	/* TODO: some FDC/drive combinations (C&T 82C711 with TEAC 1.2MB)
	 * need a stabilization period of several milliseconds to be
	 * enforced after data rate changes before R/W operations.
	 * Pause 5 msec to avoid trouble. (Needs to be 2 jiffies)
	 */
	FDCS->dtr = raw_cmd->rate & 3;
	return(wait_for_completion(jiffies+2*HZ/100,
				   (timeout_fn) floppy_ready));
} /* fdc_dtr */

static void tell_sector(void)
{
	printk(": track %d, head %d, sector %d, size %d",
	       R_TRACK, R_HEAD, R_SECTOR, R_SIZECODE);
} /* tell_sector */


/*
 * OK, this error interpreting routine is called after a
 * DMA read/write has succeeded
 * or failed, so we check the results, and copy any buffers.
 * hhb: Added better error reporting.
 * ak: Made this into a separate routine.
 */
static int interpret_errors(void)
{
	char bad;

	if (inr!=7) {
		DPRINT("-- FDC reply error");
		FDCS->reset = 1;
		return 1;
	}

	/* check IC to find cause of interrupt */
	switch (ST0 & ST0_INTR) {
		case 0x40:	/* error occurred during command execution */
			if (ST1 & ST1_EOC)
				return 0; /* occurs with pseudo-DMA */
			bad = 1;
			if (ST1 & ST1_WP) {
				DPRINT("Drive is write protected\n");
				CLEARF(FD_DISK_WRITABLE);
				cont->done(0);
				bad = 2;
			} else if (ST1 & ST1_ND) {
				SETF(FD_NEED_TWADDLE);
			} else if (ST1 & ST1_OR) {
				if (DP->flags & FTD_MSG)
					DPRINT("Over/Underrun - retrying\n");
				bad = 0;
			}else if (*errors >= DP->max_errors.reporting){
				DPRINT("");
				if (ST0 & ST0_ECE) {
					printk("Recalibrate failed!");
				} else if (ST2 & ST2_CRC) {
					printk("data CRC error");
					tell_sector();
				} else if (ST1 & ST1_CRC) {
					printk("CRC error");
					tell_sector();
				} else if ((ST1 & (ST1_MAM|ST1_ND)) || (ST2 & ST2_MAM)) {
					if (!probing) {
						printk("sector not found");
						tell_sector();
					} else
						printk("probe failed...");
				} else if (ST2 & ST2_WC) {	/* seek error */
					printk("wrong cylinder");
				} else if (ST2 & ST2_BC) {	/* cylinder marked as bad */
					printk("bad cylinder");
				} else {
					printk("unknown error. ST[0..2] are: 0x%x 0x%x 0x%x", ST0, ST1, ST2);
					tell_sector();
				}
				printk("\n");

			}
			if (ST2 & ST2_WC || ST2 & ST2_BC)
				/* wrong cylinder => recal */
				DRS->track = NEED_2_RECAL;
			return bad;
		case 0x80: /* invalid command given */
			DPRINT("Invalid FDC command given!\n");
			cont->done(0);
			return 2;
		case 0xc0:
			DPRINT("Abnormal termination caused by polling\n");
			cont->error();
			return 2;
		default: /* (0) Normal command termination */
			return 0;
	}
}

/*
 * This routine is called when everything should be correctly set up
 * for the transfer (i.e. floppy motor is on, the correct floppy is
 * selected, and the head is sitting on the right track).
 */
static void setup_rw_floppy(void)
{
	int i,ready_date,r, flags,dflags;
	timeout_fn function;

	flags = raw_cmd->flags;
	if (flags & (FD_RAW_READ | FD_RAW_WRITE))
		flags |= FD_RAW_INTR;

	if ((flags & FD_RAW_SPIN) && !(flags & FD_RAW_NO_MOTOR)){
		ready_date = DRS->spinup_date + DP->spinup;
		/* If spinup will take a long time, rerun scandrives
		 * again just before spinup completion. Beware that
		 * after scandrives, we must again wait for selection.
		 */
		if ((signed) (ready_date - jiffies) > DP->select_delay){
			ready_date -= DP->select_delay;
			function = (timeout_fn) floppy_start;
		} else
			function = (timeout_fn) setup_rw_floppy;

		/* wait until the floppy is spinning fast enough */
		if (wait_for_completion(ready_date,function))
			return;
	}
	dflags = DRS->flags;

	if ((flags & FD_RAW_READ) || (flags & FD_RAW_WRITE))
		setup_DMA();

	if (flags & FD_RAW_INTR)
		SET_INTR(main_command_interrupt);

	r=0;
	for (i=0; i< raw_cmd->cmd_count; i++)
		r|=output_byte(raw_cmd->cmd[i]);

#ifdef DEBUGT
	debugt("rw_command: ");
#endif
	if (r){
		cont->error();
		reset_fdc();
		return;
	}

	if (!(flags & FD_RAW_INTR)){
		inr = result();
		cont->interrupt();
	} else if (flags & FD_RAW_NEED_DISK)
		fd_watchdog();
}

static int blind_seek;

/*
 * This is the routine called after every seek (or recalibrate) interrupt
 * from the floppy controller.
 */
static void seek_interrupt(void)
{
#ifdef DEBUGT
	debugt("seek interrupt:");
#endif
	if (inr != 2 || (ST0 & 0xF8) != 0x20) {
		DPRINT("seek failed\n");
		DRS->track = NEED_2_RECAL;
		cont->error();
		cont->redo();
		return;
	}
	if (DRS->track >= 0 && DRS->track != ST1 && !blind_seek){
#ifdef DCL_DEBUG
		if (DP->flags & FD_DEBUG){
			DPRINT("clearing NEWCHANGE flag because of effective seek\n");
			DPRINT("jiffies=%ld\n", jiffies);
		}
#endif
		CLEARF(FD_DISK_NEWCHANGE); /* effective seek */
		DRS->select_date = jiffies;
	}
	DRS->track = ST1;
	floppy_ready();
}

static void check_wp(void)
{
	if (TESTF(FD_VERIFY)) {
		/* check write protection */
		output_byte(FD_GETSTATUS);
		output_byte(UNIT(current_drive));