tpqic02.c

powerpc内核mpc8241linux系统下char驱动程序

				stat = 0;
				while ((stat==0) && (!status_eom_detected)) {
					stat = do_qic_cmd(QCMD_RD_FM, TIM_F); /***** should use MTFSFM here???? ******/
				}
				if (tperror.exs & TP_NDT)
					return 0;
			}
			return stat;

		case MTERASE:
			tpqputs(TPQD_IOCTLS, "MTERASE -- ERASE TAPE !");
			if  ((tperror.exs & TP_ST0) && (tperror.exs & TP_WRP)) {
				tpqputs(TPQD_ALWAYS, "Cartridge is write-protected.");
				return -EACCES;
			} else {
				time_t t = jiffies;

				/* Plain GNU mt(1) 2.2 erases a tape in O_RDONLY. :-( */
				if (mode_access==READ) 
					return -EACCES;

				/* give user a few seconds to pull out tape */
				while (jiffies - t < 4*HZ)
					schedule();
			}

			/* don't bother writing filemark first */
			status_eom_detected = status_eof_detected = NO;
			return do_qic_cmd(QCMD_ERASE, TIM_R);

		case MTRAS1:
			if (TP_HAVE_RAS1) {
				tpqputs(TPQD_IOCTLS, "MTRAS1: non-destructive self test");
				stat = do_qic_cmd(QCMD_SELF_TST1, TIM_R);
				if (stat != 0) {
					tpqputs(TPQD_ALWAYS, "RAS1 failed");
					return stat;
				}
				return (tp_sense(0)==TE_OK)? 0 : -EIO; /* get_ext_status3(); */
			}
			tpqputs(TPQD_IOCTLS, "RAS1 not supported");
			return -ENXIO;

		case MTRAS2:
			if (TP_HAVE_RAS2) {
				tpqputs(TPQD_IOCTLS, "MTRAS2: destructive self test");
				stat = do_qic_cmd(QCMD_SELF_TST2, TIM_R);
				if (stat != 0) {
					tpqputs(TPQD_ALWAYS, "RAS2 failed");
					return stat;
				}
				return (tp_sense(0)==TE_OK)? 0 : -EIO; /* get_ext_status3(); */
			}
			tpqputs(TPQD_IOCTLS, "RAS2 not supported");
			return -ENXIO;

		case MTSEEK:
			if (TP_HAVE_SEEK && (QIC02_TAPE_IFC==ARCHIVE)) {
				tpqputs(TPQD_IOCTLS, "MTSEEK seeking block");
				if ((mode_access==WRITE) && status_bytes_wr)
					return -EACCES;
				/* NOTE: address (24 bits) is in seek_addr_buf[] */
				return do_qic_cmd(AR_QCMDV_SEEK_BLK, TIM_F);
			}
			else
				return -ENOTTY;

		default:
			return -ENOTTY;
	}
} /* do_ioctl_cmd */


/* dma_transfer(): This routine is called for every 512 bytes to be read
 * from/written to the tape controller. Speed is important here!
 * (There must be enough time left for the hd controller!)
 * When other devices use DMA they must ensure they use un-interruptible
 * double byte accesses to the DMA controller. Floppy.c is ok.
 * Must have interrupts disabled when this function is invoked,
 * otherwise, the double-byte transfers to the DMA controller will not
 * be atomic. That could lead to nasty problems when they are interrupted
 * by other DMA interrupt-routines.
 *
 * This routine merely does the least possible to keep
 * the transfers going:
 *	- set the DMA count register for the next 512 bytes
 *	- adjust the DMA address and page registers
 *	- adjust the timeout
 *	- tell the tape controller to start transferring
 * We assume the dma address and mode are, and remain, valid.
 */ 
static inline void dma_transfer(void)
{
	unsigned long flags;

	if (QIC02_TAPE_IFC == WANGTEK) /* or EVEREX */
		outb_p(WT_CTL_ONLINE, QIC02_CTL_PORT);	/* back to normal */
	else if (QIC02_TAPE_IFC == ARCHIVE)
		outb_p(0, AR_RESET_DMA_PORT);
	else /* QIC02_TAPE_IFC == MOUNTAIN */
		outb_p(ctlbits, QIC02_CTL_PORT);


	flags=claim_dma_lock();
	clear_dma_ff(QIC02_TAPE_DMA);
	set_dma_mode(QIC02_TAPE_DMA, dma_mode);
	set_dma_addr(QIC02_TAPE_DMA, buffaddr+dma_bytes_done);	/* full address */
	set_dma_count(QIC02_TAPE_DMA, TAPE_BLKSIZE);

	/* start tape DMA controller */
	if (QIC02_TAPE_IFC == WANGTEK) /* or EVEREX */
		outb_p(WT_CTL_DMA | WT_CTL_ONLINE, QIC02_CTL_PORT); /* trigger DMA transfer */

	else if (QIC02_TAPE_IFC == ARCHIVE) {
		outb_p(AR_CTL_IEN | AR_CTL_DNIEN, QIC02_CTL_PORT);  /* enable interrupts again */
		outb_p(0, AR_START_DMA_PORT);			  /* start DMA transfer */
		/* In dma_end() AR_RESET_DMA_PORT is written too. */

	} else /* QIC02_TAPE_IFC == MOUNTAIN */ {
		inb(MTN_R_DESELECT_DMA_PORT);
		outb_p(ctlbits | (MTN_CTL_EXC_IEN | MTN_CTL_DNIEN), QIC02_CTL_PORT);
		outb_p(0, MTN_W_SELECT_DMA_PORT);	 /* start DMA transfer */
		if (dma_mode == DMA_MODE_WRITE)
			outb_p(0, MTN_W_DMA_WRITE_PORT); /* start DMA transfer */
	}

	/* start computer DMA controller */
	enable_dma(QIC02_TAPE_DMA);

	release_dma_lock(flags);

	/* block transfer should start now, jumping to the 
	 * interrupt routine when done or an exception was detected.
	 */
} /* dma_transfer */


/* start_dma() sets a DMA transfer up between the tape controller and
 * the kernel qic02_tape_buf buffer.
 * Normally bytes_todo==dma_bytes_done at the end of a DMA transfer. If not,
 * a filemark was read, or an attempt to write beyond the End Of Tape 
 * was made. [Or some other bad thing happened.]
 * Must do a sense() before returning error.
 */
static int start_dma(short mode, unsigned long bytes_todo)
/* assume 'bytes_todo'>0 */
{
	int stat;
	unsigned long flags;
	
	tpqputs(TPQD_DEBUG, "start_dma() enter");
	TPQDEB({printk(TPQIC02_NAME ": doing_read==%d, doing_write==%d\n", doing_read, doing_write);})

	dma_bytes_done = 0;
	dma_bytes_todo = bytes_todo;
	status_error = NO;
	/* dma_mode!=0 indicates that the dma controller is in use */
	dma_mode = (mode == WRITE)? DMA_MODE_WRITE : DMA_MODE_READ;	

	/* Only give READ/WRITE DATA command to tape drive if we haven't
	 * done that already. Otherwise the drive will rewind to the beginning
	 * of the current file on tape. Any QIC command given other than
	 * R/W FM will break the read/write transfer cycle.
	 * do_qic_cmd() will terminate doing_{read,write}
	 */
	if ((doing_read == NO) && (doing_write == NO)) {
		/* First, we have to clear the status -- maybe remove TP_FIL???
		 */

#if 0
		/* Next dummy get status is to make sure CNI is valid,
                   since we're only just starting a read/write it doesn't
                   matter some exceptions are cleared by reading the status;
                   we're only interested in CNI and WRP. -Eddy */
		get_status(&tperror);
#else
		/* TP_CNI should now be handled in open(). -Hennus */
#endif

		stat = tp_sense(((mode == WRITE)? 0 : TP_WRP) | TP_BOM | TP_FIL);
		if (stat != TE_OK)
			return stat;

#if OBSOLETE
		/************* not needed iff rd_status() would wait for ready!!!!!! **********/
		if (wait_for_ready(TIM_S) != TE_OK) {	/*** not sure this is needed ***/
			tpqputs(TPQD_ALWAYS, "wait_for_ready failed in start_dma");
			return -EIO;
		}
#endif

		if (QIC02_TAPE_IFC == MOUNTAIN) {
			/* Set control bits to select ONLINE during command */
			ctlbits |= MTN_QIC02_CTL_ONLINE;
		}

		/* Tell the controller the data direction */

		/* r/w, timeout medium, check exceptions, sets status_cmd_pending. */
		stat = send_qic02_cmd((mode == WRITE)? QCMD_WRT_DATA : QCMD_RD_DATA, TIM_M, 0);
		if (stat!=TE_OK) {
			printk(TPQIC02_NAME ": start_dma: init %s failed\n",
				(mode == WRITE)? "write" : "read");
			(void) tp_sense(0);
			return stat;
		}

		/* Do this last, because sense() will clear the doing_{read,write}
		 * flags, causing trouble next time around.
		 */
		if (wait_for_ready(TIM_M) != TE_OK)
			return -EIO;
		switch (mode) {
			case READ:
				doing_read = YES;
				break;
			case WRITE:
				doing_write = YES;
				break;
			default:
				printk(TPQIC02_NAME ": requested unknown mode %d\n", mode);
				panic(TPQIC02_NAME ": invalid mode in start_dma()");
		}

	} else if (is_exception()) {
		/* This is for Archive drives, to handle reads with 0 bytes
		 * left for the last read request.
		 *
		 * ******** this also affects EOF/EOT handling! ************
		 */
		tpqputs(TPQD_ALWAYS, "detected exception in start_dma() while transfer in progress");
		status_error = YES;
		return TE_END;
	}


	status_expect_int = YES;

	/* This assumes tape is already positioned, but these
	 * semi-'intelligent' drives are unpredictable...
	 */
	TIMERON(TIM_M*2);

	/* initiate first data block read from/write to the tape controller */

	save_flags(flags);
	cli();
	dma_transfer();
	restore_flags(flags);

	TPQPUTS("start_dma() end");
	return TE_OK;
} /* start_dma */


/* This cleans up after the dma transfer has completed
 * (or failed). If an exception occurred, a sense()
 * must be done. If the exception was caused by a FM,
 * sense() will set `status_eof_detected' and
 * `status_eom_detected', as required.
 */
static void end_dma(unsigned long * bytes_done)
{
	int stat = TE_OK;
	unsigned long flags;

	TIMEROFF;

	TPQPUTS("end_dma() enter");

	flags=claim_dma_lock();
	
	disable_dma(QIC02_TAPE_DMA);
	clear_dma_ff(QIC02_TAPE_DMA);
	
	release_dma_lock(flags);

	if (QIC02_TAPE_IFC == WANGTEK) /* or EVEREX */
		outb_p(WT_CTL_ONLINE, QIC02_CTL_PORT);	/* back to normal */
	else if (QIC02_TAPE_IFC == ARCHIVE)
		outb_p(0, AR_RESET_DMA_PORT);
	else /* QIC02_TAPE_IFC == MOUNTAIN */ {
		/* Clear control bits, de-select ONLINE during tp_sense */
		ctlbits &= ~MTN_QIC02_CTL_ONLINE;
	}

	stat = wait_for_ready(TIM_M);
	if (status_error || (stat!=TE_OK)) {
		tpqputs(TPQD_DMAX, "DMA transfer exception");
		stat = tp_sense((dma_mode==READ)? TP_WRP : 0);
		/* no return here -- got to clean up first! */
	} else /* if (QIC02_TAPE_IFC == MOUNTAIN) */ {
		outb_p(ctlbits, QIC02_CTL_PORT);
	}

	if (QIC02_TAPE_IFC == MOUNTAIN)
		inb(MTN_R_DESELECT_DMA_PORT);

 	/* take the tape controller offline */

	/* finish off DMA stuff */


	dma_mode = 0;
	/* Note: The drive is left on-line, ready for the next
	 * data transfer.
	 * If the next command to the drive does not continue
	 * the pending cycle, it must do 2 sense()s first.
	 */

	*bytes_done = dma_bytes_done;
	status_expect_int = NO;
	ioctl_status.mt_blkno += (dma_bytes_done / TAPE_BLKSIZE);

	TPQPUTS("end_dma() exit");
	/*** could return stat here ***/
} /* end_dma */

/*********** Below are the (public) OS-interface procedures ***********/


/* qic02_tape_times_out() is called when a DMA transfer doesn't complete
 * quickly enough. Usually this means there is something seriously wrong
 * with the hardware/software, but it could just be that the controller
 * has decided to do a long rewind, just when I didn't expect it.
 * Just try again.
 */
static void qic02_tape_times_out(void)
{
	printk("time-out in %s driver\n", TPQIC02_NAME);
	if ((status_cmd_pending>0) || dma_mode) {
		/* takes tooo long, shut it down */
		status_dead = YES;
		status_cmd_pending = 0;
		status_timer_on = NO;
		status_expect_int = NO;
		status_error = YES;
		if (dma_mode) {
			dma_mode = 0;	/* signal end to read/write routine */
			wake_up(&qic02_tape_transfer);
		}
	}
} /* qic02_tape_times_out */

/*
 * Interrupt handling:
 *
 * 1) Interrupt is generated iff at the end of 
 *    a 512-DMA-block transfer.
 * 2) EXCEPTION is not raised unless something 
 *    is wrong or EOT/FM is detected.
 * 3) FM EXCEPTION is set *after* the last byte has
 *    been transferred by DMA. By the time the interrupt
 *    is handled, the EXCEPTION may already be set.
 *
 * So,
 * 1) On EXCEPTION, assume data has been transferred, so
 *    continue as usual, but set a flag to indicate the
 *    exception was detected.
 *    Do a sense status when the flag is found set.
 * 2) Do not attempt to continue a transfer after an exception.
 *    [??? What about marginal blocks???????]
 */


/* qic02_tape_interrupt() is called when the tape controller completes 
 * a DMA transfer.
 * We are not allowed to sleep here! 
 *
 * Check if the transfer was successful, check if we need to transfer
 * more. If the buffer contains enough data/is empty enough, signal the
 * read/write() thread to copy to/from user space.
 * When we are finished, set flags to indicate end, disable timer.
 * NOTE: This *must* be fast! 
 */
static void qic02_tape_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	int stat, r, i;
	unsigned long flags;

	TIMEROFF;

	if (status_expect_int) {
#ifdef WANT_EXTRA_FULL_DEBUGGING
		if (TP_DIAGS(current_tape_dev))
			printk("@");
#endif
		stat = inb(QIC02_STAT_PORT);	/* Knock, knock */
		if (QIC02_TAPE_IFC == ARCHIVE) {	/* "Who's there?" */
			if (((stat & (AR_STAT_DMADONE)) == 0) &&
        	              ((stat & (QIC02_STAT_EXCEPTION)) != 0)) {
				TIMERCONT;
				return;			/* "Linux with IRQ sharing" */
			}
		}

		if ((stat & QIC02_STAT_EXCEPTION) == 0) {	/* exception occurred */
			/* Possible causes for an exception during a transfer:
			 * 	- during a write-cycle: end of tape (EW) hole detected.
			 *	- during a read-cycle: filemark or EOD detected.
			 *	- something went wrong
			 * So don't continue with the next block.
			 */
			tpqputs(TPQD_ALWAYS, "isr: exception on tape controller");
			printk("      status %02x\n", stat);
			status_error = TE_EX;

			dma_bytes_done += TAPE_BLKSIZE;

			dma_mode = 0;	/* wake up rw() */
			status_expect_int = NO;
			wake_up(&qic02_tape_transfer);
			return;
		}
		/* return if tape controller not ready, or
		 * if dma channel hasn't finished last byte yet.
		 */
		r = 0;

	    /* Skip next ready check for Archive controller because
	     * it may be busy reading ahead. Weird. --hhb
	     */
		if (QIC02_TAPE_IFC == WANGTEK)	/* I think this is a drive-dependency, not IFC -- hhb */