/*
* ISR Vectoring support for the Synova Mongoose-V.
*
* COPYRIGHT (c) 1989-2001.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#include <rtems.h>
#include <stdlib.h>
#include <libcpu/mongoose-v.h>
#include <rtems/mips/iregdef.h>
#include <rtems/mips/idtcpu.h>
#include <rtems/bspIo.h> /* for printk */
int mips_default_isr( int vector )
{
unsigned int sr, sr2;
unsigned int cause;
mips_get_sr( sr );
mips_get_cause( cause );
sr2 = sr & ~0xffff;
mips_set_sr(sr2);
printk( "Unhandled isr exception: vector 0x%02x, cause 0x%08X, sr 0x%08X\n", vector, cause, sr );
rtems_fatal_error_occurred(1);
return 0;
}
/* userspace routine to assert either software interrupt */
int assertSoftwareInterrupt( uint32_t n )
{
if( n<2 )
{
uint32_t c;
mips_get_cause(c);
c = ((n+1) << CAUSE_IPSHIFT);
mips_set_cause(c);
return n;
}
else return -1;
}
#define CALL_ISR(_vector,_frame) \
do { \
if( _ISR_Vector_table[_vector] ) \
(_ISR_Vector_table[_vector])(_vector,_frame); \
else \
mips_default_isr(_vector); \
} while (0)
/*
* Instrumentation tweaks for isr timing measurement, turning them off
* via this #if will remove the code entirely from the RTEMS kernel.
*/
#if 0
#define SET_ISR_FLAG( offset ) *((uint32_t*)(0x8001e000+offset)) = 1;
#define CLR_ISR_FLAG( offset ) *((uint32_t*)(0x8001e000+offset)) = 0;
#else
#define SET_ISR_FLAG( offset )
#define CLR_ISR_FLAG( offset )
#endif
static volatile uint32_t _ivcause, _ivsr;
static uint32_t READ_CAUSE(void)
{
mips_get_cause( _ivcause );
_ivcause &= SR_IMASK; /* mask off everything other than the interrupt bits */
return ((_ivcause & (_ivsr & SR_IMASK)) >> CAUSE_IPSHIFT);
}
/*
* This rather strangely coded routine enforces an interrupt priority
* scheme. As it runs thru finding whichever interrupt caused it to get
* here, it test for other interrupts arriving in the meantime (maybe it
* occured while the vector code is executing for instance). Each new
* interrupt will be served in order of its priority. In an effort to
* minimize overhead, the cause register is only fetched after an
* interrupt is serviced. Because of the intvect goto's, this routine
* will only exit when all interrupts have been serviced and no more
* have arrived, this improves interrupt latency at the cost of
* increasing scheduling jitter; though scheduling jitter should only
* become apparent in high interrupt load conditions.
*/
void mips_vector_isr_handlers( CPU_Interrupt_frame *frame )
{
uint32_t cshifted;
/* mips_get_sr( sr ); */
_ivsr = frame->c0_sr;
cshifted = READ_CAUSE();
intvect:
if( cshifted & 0x3 )
{
/* making the software interrupt the highest priority is kind of
* stupid, but it makes the bit testing lots easier. On the other
* hand, these ints are infrequently used and the testing overhead
* is minimal. Who knows, high-priority software ints might be
* handy in some situation.
*/
/* unset both software int cause bits */
mips_set_cause( _ivcause & ~(3 << CAUSE_IPSHIFT) );
if ( cshifted & 0x01 ) /* SW[0] */
{
CALL_ISR( MONGOOSEV_IRQ_SOFTWARE_1, frame );
}
if ( cshifted & 0x02 ) /* SW[1] */
{
CALL_ISR( MONGOOSEV_IRQ_SOFTWARE_2, frame );
}
cshifted = READ_CAUSE();
}
if ( cshifted & 0x04 ) /* IP[0] ==> INT0 == TIMER1 */
{
SET_ISR_FLAG( 0x4 );
CALL_ISR( MONGOOSEV_IRQ_TIMER1, frame );
CLR_ISR_FLAG( 0x4 );
if( (cshifted = READ_CAUSE()) & 0x3 ) goto intvect;
}
if ( cshifted & 0x08 ) /* IP[1] ==> INT1 == TIMER2*/
{
SET_ISR_FLAG( 0x8 );
CALL_ISR( MONGOOSEV_IRQ_TIMER2, frame );
CLR_ISR_FLAG( 0x8 );
if( (cshifted = READ_CAUSE()) & 0x7 ) goto intvect;
}
if ( cshifted & 0x10 ) /* IP[2] ==> INT2 */
{
SET_ISR_FLAG( 0x10 );
CALL_ISR( MONGOOSEV_IRQ_INT2, frame );
CLR_ISR_FLAG( 0x10 );
if( (cshifted = READ_CAUSE()) & 0xf ) goto intvect;
}
if ( cshifted & 0x20 ) /* IP[3] ==> INT3 == FPU interrupt */
{
SET_ISR_FLAG( 0x20 );
CALL_ISR( MONGOOSEV_IRQ_INT3, frame );
CLR_ISR_FLAG( 0x20 );
if( (cshifted = READ_CAUSE()) & 0x1f ) goto intvect;
}
if ( cshifted & 0x40 ) /* IP[4] ==> INT4, external interrupt */
{
SET_ISR_FLAG( 0x40 );
CALL_ISR( MONGOOSEV_IRQ_INT4, frame );
CLR_ISR_FLAG( 0x40 );
if( (cshifted = READ_CAUSE()) & 0x3f ) goto intvect;
}
if ( cshifted & 0x80 ) /* IP[5] ==> INT5, peripheral interrupt */
{
uint32_t bit;
uint32_t pf_icr, pf_mask, pf_reset = 0;
uint32_t i, m;
pf_icr = MONGOOSEV_READ( MONGOOSEV_PERIPHERAL_FUNCTION_INTERRUPT_CAUSE_REGISTER );
/*
for (bit=0, pf_mask = 1; bit < 32; bit++, pf_mask <<= 1 )
{
if ( pf_icr & pf_mask )
{
SET_ISR_FLAG( 0x80 + (bit*4) );
CALL_ISR( MONGOOSEV_IRQ_PERIPHERAL_BASE + bit, frame );
CLR_ISR_FLAG( 0x80 + (bit*4) );
pf_reset |= pf_mask;
if( (cshifted = READ_CAUSE()) & 0xff ) break;
}
}
*/
/*
* iterate thru 32 bits in 4 chunks of 8 bits each. This lets us
* quickly get past unasserted interrupts instead of flogging our
* way thru a full 32 bits. pf_mask shifts left 8 bits at a time
* to serve as a interrupt cause test mask.
*/
for( bit=0, pf_mask = 0xff; (bit < 32 && pf_icr); (bit+=8, pf_mask <<= 8) )
{
if ( pf_icr & pf_mask )
{
/* one or more of the 8 bits we're testing is high */
m = (1 << bit);
/* iterate thru the 8 bits, servicing any of the interrupts */
for(i=0; (i<8 && pf_icr); (i++, m <<= 1))
{
if( pf_icr & m )
{
SET_ISR_FLAG( 0x80 + ((bit + i) * 4) );
CALL_ISR( MONGOOSEV_IRQ_PERIPHERAL_BASE + bit + i, frame );
CLR_ISR_FLAG( 0x80 + ((bit + i) * 4) );
/* or each serviced interrupt into our interrupt clear mask */
pf_reset |= m;
/* xor off each int we service so we can immediately
* exit once we get the last one
*/
pf_icr %= m;
/* if another interrupt has arrived, jump out right
* away but be sure to reset all the interrupts we've
* already serviced
*/
if( READ_CAUSE() & 0xff ) goto pfexit;
}
}
}
}
pfexit:
MONGOOSEV_WRITE( MONGOOSEV_PERIPHERAL_STATUS_REGISTER, pf_reset );
}
/*
* this is a last ditch interrupt check, if an interrupt arrives
* after this step, servicing it will incur the entire interrupt
* overhead cost.
*/
if( (cshifted = READ_CAUSE()) & 0xff ) goto intvect;
}
