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coherent
/* (-lgl
* COHERENT Driver Kit Version 1.1.0
* Copyright (c) 1982, 1990 by Mark Williams Company.
* All rights reserved. May not be copied without permission.
-lgl) */
/*
* This is a driver for the
* Archive SC-400 Series Tape Controller.
*/
#include <sys/coherent.h>
#include <sys/buf.h>
#include <sys/con.h>
#include <sys/const.h>
#include <sys/devices.h>
#include <sys/inode.h>
#include <sys/mtioctl.h>
#include <sys/sched.h>
#include <sys/seg.h>
#include <sys/stat.h>
#include <sys/uproc.h>
#include <errno.h>
/*
* Fixed parameters.
*/
#define NCMDS 8 /* Max # chained commands */
/*
* Configurable parameters
*/
int STIRQ = 3; /* IRQ Level 3 */
int STPORT = 0x200; /* I/O Port */
int STDMA = 1; /* DMA Channel */
#define BIT(n) (1 << (n))
/*
* Forward referenced functions.
*/
void stcache();
void stflush();
void stinvoke();
void ststart();
void stintr();
void strecov();
void stnext();
void stdiag();
void stspin();
/*
* Driver configuration.
*/
int stload();
int stuload();
int stopen();
int stclose();
int stread();
int stwrite();
int stioctl();
void stwatch();
int nulldev();
int nonedev();
CON stcon = {
DFCHR, /* Flags */
ST_MAJOR, /* Major index */
stopen, /* Open */
stclose, /* Close */
nonedev, /* Block */
stread, /* Read */
stwrite, /* Write */
stioctl, /* Ioctl */
nulldev, /* Powerfail */
stwatch, /* Timeout */
stload, /* Load */
stuload /* Unload */
};
/*
* I/O Port Addresses
*/
#define DATA_REG (STPORT+0) /* Data register */
#define CTRL_REG (STPORT+1) /* Control/Status register */
#define DMAGO_REG (STPORT+2) /* DMA Go register */
#define DMARST_REG (STPORT+3) /* DMA reset register */
/*
* Control Register
*/
#define CR_RSTSAC BIT(7) /* 1 -> reset control micro */
#define CR_REQ BIT(6) /* 1 -> request to LSI chip */
#define CR_IEN BIT(5) /* 1 -> enables interrupts */
#define CR_DNIEN BIT(4) /* 1 -> enable DONE interrupts */
/*
* Status Register
*/
#define SR_IRQF BIT(7) /* 1 -> Interrupt Request Flag */
#define SR_NRDY BIT(6) /* 0 -> Ready */
#define SR_NEXC BIT(5) /* 0 -> Exception */
#define SR_DONE BIT(4) /* 1 -> DMA Done */
#define SR_TO_PC BIT(3) /* 1 -> Direction is to PC */
/*
* Controller Commands.
*/
#define CC_SELECT 0x01 /* Select Drive 0 */
#define CC_LOCK 0x11 /* Select Drive 0 and Lock */
#define CC_BOT 0x21 /* Rewind to beginning of tape */
#define CC_ERASE 0x22 /* Completely erase cartridge */
#define CC_TENSION 0x24 /* Wind tape to BOT, EOT, BOT */
#define CC_AUTO 0x25 /* Select auto-initialization */
#define CC_QIC11 0x26 /* Select QIC-11 media format */
#define CC_QIC24 0x27 /* Select QIC-24 media format */
#define CC_WRITE 0x40 /* Write to tape */
#define CC_WFM 0x60 /* Write file mark */
#define CC_READ 0x80 /* Read from tape */
#define CC_RFM 0xA0 /* Skip past next file mark */
#define CC_SENSE 0xC0 /* Read controller status */
/*
* Sense Status Bytes 0 and 1.
*/
#define SS0_FIL BIT(0) /* File Mark Detected */
#define SS0_BNL BIT(1) /* Bad Block Not located */
#define SS0_UDA BIT(2) /* Unrecoverable data error */
#define SS0_EOM BIT(3) /* End of media */
#define SS0_WRP BIT(4) /* Write Protected Cartridge */
#define SS0_USL BIT(5) /* Unselected Drive */
#define SS0_CNI BIT(6) /* Cartridge Not In Place */
#define SS0_ERR (SS0_BNL+SS0_UDA+SS0_USL+SS0_CNI)
#define SS1_POR BIT(0) /* Power on Reset Occurred */
#define SS1_BOM BIT(3) /* Beginning of media */
#define SS1_MBD BIT(4) /* Marginal Block Detected */
#define SS1_NDT BIT(5) /* No Data Detected */
#define SS1_ILL BIT(6) /* Illegal Command */
#define SS1_ERR (SS1_NDT+SS1_ILL)
/*
* Device States.
*/
#define SDEAD 0 /* controller not found */
#define SIDLE 1 /* controller idle */
#define SCMD 2 /* initiating command */
#define SRUN 3 /* performing command */
#define SRDWR 4 /* starting read/write */
#define SBLOCK 5 /* performing read/write */
#define SBLEND 6 /* concluding block i/o */
#define SSENSE 7 /* reading status bytes */
#define SSDONE 8 /* concluding status sense */
/*
* Driver State Information.
*/
struct st_s {
int st_state;
int st_mode; /* IPR or IPW */
int st_iocmd; /* CC_READ or CC_WRITE */
int st_cmd; /* last command executed */
int st_cmds[NCMDS]; /* list of chained commands */
int st_ncmds; /* num of chained commands */
int st_iswr;
int st_wasio;
int st_iseof;
int st_error;
paddr_t st_paddr;
fsize_t st_resid;
fsize_t st_size;
saddr_t st_sel;
SEG * st_seg;
char st_status[6];
int st_nstat;
int st_rdys; /* number of ready watchdogs */
int st_nlost; /* number of lost interrupts */
} st;
/**
*
* void
* stload() -- initialize tape device
*
* Action: Reset tape controller and drive.
* Seize tape interrupt vector.
*
* Note: If the tape controller is present and operational,
* a interrupt will occur and set st.st_state to SIDLE.
*/
static
stload()
{
/*
* Paranoia - Turn off DMA.
* Should already be turned off.
*/
dmaoff( STDMA );
/*
* Reset tape controller and drive
*/
outb( CTRL_REG, CR_RSTSAC );
/*
* Wait at least 25 microseconds
*/
stspin( 25 );
/*
* Terminate reset condition
*/
outb( CTRL_REG, CR_IEN );
/*
* Seize tape interrupt vector.
*/
setivec( STIRQ, &stintr );
}
/**
*
* stuload( dev ) -- Unload tape device.
* dev_t dev;
*/
stuload( dev )
dev_t dev;
{
/*
* Turn off DMA.
*/
dmaoff( STDMA );
/*
* Release tape interrupt vector.
*/
clrivec( STIRQ );
/*
* Disable tape interrupts.
*/
outb( CTRL_REG, 0 );
}
/**
*
* stopen( dev, mode ) -- open tape device
* dev_t dev;
* int mode;
*
* Input: dev = tape device to be opened.
* mode = desired access mode.
*
* Action: Refuse access if tape drive does not exist or is in use.
* Refuse simultaneous read and write access.
* Refuse access if cartridge is not inserted in tape drive.
* Refuse write access to a write protected cartridge.
* Allocate tape cache.
* Initialize device state.
* Lock tape cartridge.
*/
static
stopen( dev, mode )
register dev_t dev;
register int mode;
{
int s;
/*
* Refuse access if no tape drive.
*/
if ( st.st_state == SDEAD ) {
u.u_error = ENXIO;
return;
}
/*
* Refuse access if tape drive is already open.
*/
if ( st.st_mode != 0 ) {
u.u_error = EDBUSY;
return;
}
/*
* Access must be read-only or write-only.
*/
if ( (mode != IPR) && (mode != IPW) ) {
u.u_error = EINVAL;
return;
}
/*
* Wait for tape drive to become idle.
*/
if ( stwait() < 0 ) {
u.u_error = EINTR;
return;
}
/*
* Initialize tape interface.
*/
s = sphi();
outb( DMARST_REG, 0 );
outb( CTRL_REG, CR_IEN );
spl( s );
/*
* Obtain tape status.
*/
stinvoke( CC_SENSE );
/*
* Wait for tape status.
*/
if ( stwait() < 0 ) {
u.u_error = EINTR;
return;
}
/*
* Refuse access if no cartridge.
*/
if ( st.st_status[0] & (SS0_CNI|SS0_USL) ) {
u.u_error = EDATTN;
return;
}
/*
* Refuse write access to a write protected cartridge.
*/
if ( (mode == IPW) && (st.st_status[0] & SS0_WRP) ) {
u.u_error = EROFS;
return;
}
/*
* Calculate desired cache size in Kbytes.
*/
st.st_size = minor(dev) & ~0x80;
if ( st.st_size == 0 )
st.st_size = 256;
/*
* Allocate cache
*/
for ( st.st_size *= 1024; st.st_size != 0; st.st_size -= 1024 )
if ( st.st_seg = salloc( st.st_size, SFSYST|SFNSWP|SFNCLR ) )
break;
/*
* Refuse access if couldn't allocate cache.
*/
if ( st.st_seg == 0 ) {
u.u_error = ENOMEM;
return;
};
/*
* Initialize device state.
*/
st.st_sel = FP_SEL(st.st_seg->s_faddr);
st.st_iswr = (mode == IPW);
st.st_paddr = st.st_seg->s_paddr;
st.st_resid = (mode == IPW) ? st.st_size : 0 ;
st.st_iocmd = (mode == IPW) ? CC_WRITE : CC_READ ;
st.st_mode = mode;
st.st_iseof = 0;
st.st_wasio = 0;
st.st_error = 0;
st.st_rdys = 0;
st.st_nlost = 0;
/*
* Lock cartridge if at beginning of media.
*/
if ( st.st_status[1] & SS1_BOM )
stinvoke( CC_LOCK );
}
/**
*
* stclose( dev, mode ) -- close tape device
* dev_t dev;
* int mode;
*
* Input: dev = tape device to be closed.
* mode = access mode.
*
* Action: If access mode was for writing, flush the tape cache.
* If data was written to tape, write a file mark.
* If data was read from tape on the non rewinding device,
* read until end of file or an error is encountered.
* Rewind the tape if the rewinding device is open.
* Unlock the tape cartridge.
* Clear tape state and release tape cache memory.
*/
static
stclose( dev, mode )
register dev_t dev;
{
/*
* Check if tape was opened for writing.
*/
if ( st.st_iswr ) {
/*
* Flush the tape cache.
*/
stflush();
/*
* Write a file mark if data was written to tape.
*/
if ( st.st_wasio )
stinvoke( CC_WFM );
}
/*
* Check if non-rewinding device was opened for reading.
*/
else if ( st.st_wasio && (dev & 0x80 ) ) {
/*
* Read file mark if not just past one.
*/
if ( (st.st_status[0] & SS0_FIL) == 0 )
stinvoke( CC_RFM );
}
/*
* Rewinding device.
*/
if ( (dev & 0x80) == 0 ) {
/*
* Wait for controller to idle.
*/
while ( stwait() < 0 )
;
/*
* Initiate rewind.
*/
stinvoke( CC_BOT );
/*
* Unlock the drive [turn off the light].
*/
stinvoke( CC_SELECT );
}
/*
* Clear tape state, releasing tape cache.
*/
sfree( st.st_seg );
st.st_seg = 0;
st.st_mode = 0;
}
/**
*
* stread( dev, iop ) -- tape device read
* dev_t dev;
* IO * iop;
*
* Input: dev = tape device to be read from.
* iop = pointer to IO structure.
*
* Action: Transfer data from tape cache to user memory,
* filling the cache as required by initiating reads from tape.
*/
static
stread( dev, iop )
dev_t dev;
register IO * iop;
{
register int n;
register int ioc;
ioc = iop->io_ioc;
while ( iop->io_ioc > 0 ) {
/*
* Check for empty cache.
*/
while ( st.st_resid == 0 ) {
/*
* Special handling if end of file was encountered.
*/
if ( st.st_iseof ) {
/*
* Clear EOF if no data was transferred yet.
*/
if ( ioc == iop->io_ioc )
st.st_iseof = 0;
return;
}
/*
* Abort on I/O error.
*/
if ( u.u_error = st.st_error ) {
stdiag();
return;
}
/*
* Fill the cache from tape.
*/
stcache();
}
/*
* Determine max data transferable in one chunk.
*/
n = iop->io_ioc;
if ( n > st.st_resid )
n = st.st_resid;
/*
* Transfer some data from cache to user memory.
*/
if ( pucopy( st.st_paddr, iop->io_base, n ) != n )
return;
/*
* Update addresses and counts.
*/
iop->io_base += n;
iop->io_ioc -= n;
st.st_resid -= n;
st.st_paddr += n;
}
}
/**
*
* stwrite( dev, iop ) -- write to tape device
* dev_t dev;
* IO * iop;
*
* Input: dev = tape device to be written to.
* iop = pointer to IO structure.
*
* Action: Transfer data from user memory to tape cache,
* flushing the cache as required by initiating writes to tape.
*/
static
stwrite( dev, iop )
dev_t dev;
register IO *iop;
{
register int n;
while ( iop->io_ioc > 0 ) {
/*
* Determine max data transferable in one chunk.
*/
n = iop->io_ioc;
if ( n > st.st_resid )
n = st.st_resid;
/*
* Transfer some data from user memory to cache.
*/
if ( upcopy( iop->io_base, st.st_paddr, n ) != n )
break;
/*
* Update addresses and counts.
*/
iop->io_base += n;
iop->io_ioc -= n;
st.st_paddr += n;
st.st_resid -= n;
/*
* Flush the cache to tape if full.
*/
if ( st.st_resid == 0 )
stflush();
/*
* Abort on I/O error.
*/
if ( u.u_error = st.st_error ) {
stdiag();
return;
}
}
}
/**
*
* stioctl( dev, cmd, arg ) -- service tape I/O control requests
* int dev;
* int cmd;
* int arg;
*
* Input: dev = tape device to be serviced
* cmd = ioctl command
* arg = argument to ioctl command
*
* Action: Service tape I/O control request.
*/
static
stioctl( dev, cmd, arg )
{
if ( st.st_iswr )
stflush();
st.st_error = EINVAL;
switch ( cmd ) {
case MTERASE:
stinvoke( CC_ERASE );
break;
case MTTENSE:
stinvoke( CC_TENSION );
break;
case MTREWIND:
if ( st.st_iswr && st.st_wasio ) {
stinvoke( CC_WFM );
st.st_wasio = 0;
}
stinvoke( CC_BOT );
break;
case MTWEOF:
if ( st.st_iswr ) {
stinvoke( CC_WFM );
st.st_wasio = 0;
}
break;
case MTFSKIP:
if ( ! st.st_iswr ) {
if ( ! st.st_iseof )
stinvoke( CC_RFM );
st.st_iseof = 0;
st.st_resid = 0;
}
break;
}
/*
* Record tape error code.
*/
u.u_error = st.st_error;
}
/**
*
* void
* stcache() -- read from tape into cache
*
* Action: Read as much data as possible into the tape cache.
* Set st.st_paddr to the cache address.
* Set st.st_resid to the number of data bytes in the cache.
*/
static void
stcache()
{
/*
* Try to fill cache from tape.
*/
st.st_paddr = st.st_seg->s_paddr;
st.st_resid = st.st_size;
ststart();
/*
* Update cache information.
*/
st.st_paddr = st.st_seg->s_paddr;
st.st_resid = st.st_size - st.st_resid;
/*
* Clear the cache on I/O error.
*/
if ( st.st_error )
st.st_resid = 0;
}
/**
*
* void
* stflush() -- flush cache to tape
*
* Action: Ensure tape cache is block aligned.
* Write cache to the tape.
* Set st.st_paddr to the cache address.
* Set st.st_resid to the number of cache bytes available.
*/
static void
stflush()
{
static char zc;
/*
* Check for empty cache.
*/
if ( st.st_resid == st.st_size )
return;
/*
* Block align the cache.
*/
while ( st.st_resid % BSIZE ) {
kpcopy( &zc, st.st_paddr, 1 );
st.st_paddr++;
st.st_resid--;
}
/*
* Flush the cache to tape.
*/
st.st_paddr = st.st_seg->s_paddr;
st.st_resid = st.st_size - st.st_resid;
ststart();
/*
* Update cache information.
*/
st.st_paddr = st.st_seg->s_paddr;
st.st_resid = st.st_size;
}
/**
*
* void
* stinvoke() -- start tape control operation
*
* Action: Initiate tape control operation.
*/
static void
stinvoke( cmd )
int cmd;
{
register int s;
/*
* Disable interrupts.
*/
s = sphi();
/*
* Wait for controller to become idle.
*/
while ( st.st_state != SIDLE ) {
/*
* Create chained command if possible.
*/
if ( st.st_ncmds < NCMDS ) {
st.st_cmds[ st.st_ncmds++ ] = cmd;
spl( s );
return;
}
sleep( &st, CVTTOUT, IVTTOUT, SVTTOUT );
}
/*
* Setup for tape operation.
*/
drvl[ST_MAJOR].d_time = 1;
st.st_state = SCMD;
st.st_error = 0;
st.st_rdys = 0;
stspin( 100 );
/*
* Request tape operation.
* Do NOT wait for results.
*/
outb( DATA_REG, st.st_cmd = cmd );
outb( CTRL_REG, CR_IEN+CR_REQ );
/*
* Enable interrupts.
*/
spl( s );
}
/**
*
* void
* ststart() -- start tape read/write operation
*
* Action: Initiate tape read/write operation.
* Wait for tape operation to complete.
*/
static void
ststart()
{
register int s;
/*
* Disable interrupts.
*/
s = sphi();
/*
* Wait for controller to become idle.
*/
while ( st.st_state != SIDLE )
sleep( &st, CVTTOUT, IVTTOUT, SVTTOUT );
/*
* Setup for tape read/write.
*/
drvl[ST_MAJOR].d_time = 1;
st.st_state = SRDWR;
st.st_error = 0;
st.st_rdys = 0;
stspin( 100 );
/*
* Tape read/write was last command executed.
*/
if ( st.st_cmd == st.st_iocmd ) {
/*
* Resume tape i/o operation.
* Simulate RDY interrupt.
*/
stintr();
}
else {
/*
* Request tape operation.
*/
outb( DATA_REG, st.st_cmd = st.st_iocmd );
outb( CTRL_REG, CR_IEN+CR_REQ );
}
/*
* Wait for tape operation to complete.
*/
while ( st.st_state != SIDLE )
sleep( &st, CVTTOUT, IVTTOUT, SVTTOUT );
/*
* Enable interrupts.
*/
spl( s );
}
/**
*
* void
* stintr() -- tape interrupt handler
*
* Action: Service tape interrupts.
* Perform transitions to new tape states.
* Wake sleeping processes if appropriate.
*/
static void
stintr()
{
register int csr;
register int s;
s = sphi();
csr = inb( CTRL_REG );
/*
* Initiate exception recovery.
*/
if ( (csr & SR_NEXC) == 0 ) {
strecov();
spl( s );
return;
}
/*
* Clear ready watchdog count.
*/
st.st_rdys = 0;
/*
* Process normal operations.
*/
switch ( st.st_state ) {
case SCMD:
/*
* Command has been acknowledged.
* Wait for command completion.
*/
outb( CTRL_REG, CR_IEN );
st.st_state = (st.st_cmd == CC_SENSE) ? SSENSE : SRUN;
st.st_nstat = 0;
break;
case SRUN:
/*
* Command has completed.
* Chain a sense status command if no other chained commands.
*/
if ( st.st_ncmds == 0 )
st.st_cmds[ st.st_ncmds++ ] = CC_SENSE;
/*
* Initiate next chained command.
*/
stnext();
break;
case SRDWR:
/*
* Read/Write command had been acknowledged.
* Clear tape request, enable done interrupt.
*/
outb( CTRL_REG, CR_IEN+CR_DNIEN );
/*
* Define direct memory access parameters.
*/
dmaon( STDMA, st.st_paddr, BSIZE, st.st_iswr );
/*
* If tape read command, wait for interface to switch direction
*/
if ( st.st_iocmd == CC_READ )
while ( (inb(CTRL_REG) & SR_TO_PC) != SR_TO_PC )
;
/*
* Enable DMA transfer on tape interface and at DMA controller chip.
*/
st.st_state = SBLOCK;
outb( DMAGO_REG, 0 );
dmago( STDMA );
break;
case SBLOCK:
/*
* Perform Block I/O.
* Ignore RDY interrupt, wait for [DMA] DONE interrupt.
*/
if ( (csr & SR_DONE) == 0 )
break;
/*
* Turn off DMA.
*/
dmaoff( STDMA );
/*
* If more data remains to be transferred, reenable DMA.
* NOTE: do -= BEFORE if() to avoid potential compiler bug.
*/
st.st_resid -= BSIZE;
if ( st.st_resid > 0 ) {
st.st_paddr += BSIZE;
dmaon( STDMA, st.st_paddr, BSIZE, st.st_iswr );
outb( DMAGO_REG, 0 );
dmago( STDMA );
break;
}
/*
* Disable done interrupt.
* Wait for I/O completion.
*/
outb( CTRL_REG, CR_IEN );
st.st_state = SBLEND;
break;
case SBLEND:
/*
* Completion of Block I/O.
* Clear the file mark and beginning of media indicators.
* Record the fact that data has been transferred.
*/
st.st_status[0] &= ~SS0_FIL;
st.st_status[1] &= ~SS1_BOM;
st.st_wasio = 1;
stnext();
break;
case SSENSE:
/*
* Sense Status Byte.
* Wait for availability.
*/
do {
csr = inb(CTRL_REG) & (SR_NRDY|SR_TO_PC);
} while ( csr != SR_TO_PC );
/*
* Save status byte.
*/
st.st_status[st.st_nstat] = inb(DATA_REG);
/*
* Acknowledge reception.
* CR_REQ must be present for at least 20 microseconds.
*/
outb( CTRL_REG, CR_IEN+CR_REQ );
stspin( 20 );
outb( CTRL_REG, CR_IEN );
/*
* Change state to status completion if all bytes saved.
*/
if ( ++(st.st_nstat) == 6 )
st.st_state = SSDONE;
break;
case SSDONE:
/*
* Completion of Sense Status Command.
* Check for file mark.
*/
if ( st.st_status[0] & SS0_FIL ) {
outb( DMARST_REG, 0 );
st.st_iseof = 1;
}
/*
* Check for I/O error.
*/
else if ( (st.st_status[0] & SS0_ERR) ||
(st.st_status[1] & SS1_ERR) ) {
st.st_error = EIO;
}
/*
* Check for write protected cartridge.
*/
else if ( (st.st_iocmd == CC_WRITE) &&
(st.st_status[0] & SS0_WRP) ) {
st.st_error = EROFS;
}
stnext();
break;
}
spl( s );
}
/**
*
* void
* strecov() -- initiate recovery from exception conditions
*
* Action: Invoked when the tape controller asserts EXCEPTION.
* A sense status command is initiated to clear the exception.
*/
static void
strecov()
{
/*
* Ensure tape interface is idle.
*/
outb( CTRL_REG, CR_IEN );
stspin( 100 );
/*
* Turn off DMA on read/write exception.
*/
if ( st.st_cmd == st.st_iocmd )
dmaoff( STDMA );
/*
* Initiate sense status command.
*/
outb( DATA_REG, st.st_cmd = CC_SENSE );
outb( CTRL_REG, CR_IEN+CR_REQ );
drvl[ST_MAJOR].d_time = 1;
st.st_state = SCMD;
st.st_error = 0;
st.st_rdys = 0;
}
/**
*
* static void
* stnext() -- initiate next chained command.
*/
static void
stnext()
{
/*
* Ensure tape interface is idle.
*/
outb( CTRL_REG, CR_IEN );
drvl[ST_MAJOR].d_time = 0;
st.st_state = SIDLE;
stspin( 100 );
/*
* Initiate a chained command.
*/
if ( st.st_ncmds ) {
outb( DATA_REG, st.st_cmd = st.st_cmds[ --st.st_ncmds ] );
outb( CTRL_REG, CR_IEN+CR_REQ );
drvl[ST_MAJOR].d_time = 1;
st.st_state = SCMD;
st.st_error = 0;
st.st_rdys = 0;
return;
}
/*
* Wake waiting processes.
*/
wakeup( &st );
}
/**
*
* void
* stwatch() -- periodic [1 sec] watchdog
*
* Action: If an exception condition exists, initate recovery actions.
* If ready condition exists for 1-2 seconds, simulate interrupt.
*
* Notes: If an exception condition occurs after a ready interrupt has
* been serviced, but before the ready condition is cleared,
* the exception interrupt will not occur, and is simulated here.
*/
static void
stwatch()
{
register int csr;
register int s;
/*
* Disable interrupts, preventing critical race with stintr().
*/
s = sphi();
csr = inb(CTRL_REG);
/*
* Initiate recovery from exception conditions.
*/
if ( (csr & SR_NEXC) == 0 )
strecov();
/*
* Reset ready watchdog if not ready.
*/
else if ( csr & SR_NRDY )
st.st_rdys = 0;
/*
* Simulate lost ready interrupts after 2 seconds.
*/
else if ( ++st.st_rdys >= 2 )
stintr();
/*
* Enable interrupts.
*/
spl( s );
}
/**
*
* void
* stdiag() - Report tape status.
*
* Action: Identify and report the highest priority tape error.
* There will normally only be one valid error present.
* The USL error can invalidate most remaining flags.
* The CNI error can invalidate cartridge related flags.
*
* Notes: Never called from interrupt level, but always from background.
*/
static void
stdiag()
{
if ( st.st_status[0] & SS0_USL )
printf( "st: Unselected Drive\n" );
else if ( st.st_status[0] & SS0_CNI )
printf( "st: Cartridge missing\n" );
else if ( st.st_status[1] & SS1_NDT )
printf( "st: No data detected\n" );
else if ( st.st_status[0] & SS0_BNL )
printf( "st: Bad block not located\n" );
else if ( st.st_status[0] & SS0_UDA )
printf( "st: Unrecoverable data error\n" );
else if ( st.st_status[1] & SS1_ILL )
printf( "st: Illegal command\n" );
else
printf( "st: %x\n", (st.st_status[1] << 8) + st.st_status[0] );
}
/**
*
* int
* stwait() -- wait for tape controller to idle.
*
* Return: 0 = tape controller idle.
* -1 = signal received.
*/
static int
stwait()
{
int s;
s = sphi();
while ( st.st_state != SIDLE ) {
sleep( &st, CVTTOUT, IVTTOUT, SVTTOUT );
if ( SELF->p_ssig ) {
spl( s );
return -1;
}
}
spl( s );
return 0;
}
/**
*
* void
* stspin( usec ) -- delay execution
* int usec;
*
* Input: usec = number of micro-seconds to delay.
*
* Action: Wait at least 'usec' micro-seconds.
*
* Notes: Provides minimum delay required at times by tape controller.
* Should function properly up to at least 16 Mhz system clock.
*/
static void
stspin( usec )
register int usec;
{
while ( --usec >= 0 )
;
}
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