/*
* Mips CPU Dependent Source
*
* 2002: Greg Menke (gregory.menke@gsfc.nasa.gov)
* Overhauled interrupt level and interrupt enable/disable code
* to more exactly support MIPS. Our mods were for MIPS1 processors
* MIPS3 ports are affected, though apps written to the old behavior
* should still work OK.
*
* Conversion to MIPS port by Alan Cudmore <alanc@linuxstart.com> and
* Joel Sherrill <joel@OARcorp.com>.
*
* These changes made the code conditional on standard cpp predefines,
* merged the mips1 and mips3 code sequences as much as possible,
* and moved some of the assembly code to C. Alan did much of the
* initial analysis and rework. Joel took over from there and
* wrote the JMR3904 BSP so this could be tested. Joel also
* added the new interrupt vectoring support in libcpu and
* tried to better support the various interrupt controllers.
*
* Original MIP64ORION port by Craig Lebakken <craigl@transition.com>
* COPYRIGHT (c) 1996 by Transition Networks Inc.
*
* To anyone who acknowledges that this file is provided "AS IS"
* without any express or implied warranty:
* permission to use, copy, modify, and distribute this file
* for any purpose is hereby granted without fee, provided that
* the above copyright notice and this notice appears in all
* copies, and that the name of Transition Networks not be used in
* advertising or publicity pertaining to distribution of the
* software without specific, written prior permission.
* Transition Networks makes no representations about the
* suitability of this software for any purpose.
*
* 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.com/license/LICENSE.
*
* $Id$
*/
#include <rtems/system.h>
#include <rtems/score/isr.h>
#include <rtems/score/wkspace.h>
/*
** local dword used in cpu_asm to pass the exception stack frame to the
** context switch code.
*/
unsigned __exceptionStackFrame = 0;
/* _CPU_Initialize
*
* This routine performs processor dependent initialization.
*
* INPUT PARAMETERS:
* cpu_table - CPU table to initialize
* thread_dispatch - address of disptaching routine
*/
void _CPU_Initialize(
rtems_cpu_table *cpu_table,
void (*thread_dispatch) /* ignored on this CPU */
)
{
/*
* If there is not an easy way to initialize the FP context
* during Context_Initialize, then it is usually easier to
* save an "uninitialized" FP context here and copy it to
* the task's during Context_Initialize.
*/
/* FP context initialization support goes here */
_CPU_Table = *cpu_table;
}
/*PAGE
*
* _CPU_ISR_Get_level
*
* This routine returns the current interrupt level.
*/
unsigned32 _CPU_ISR_Get_level( void )
{
unsigned int sr;
mips_get_sr(sr);
//printf("current sr=%08X, ",sr);
#if __mips == 3
/* EXL bit and shift down hardware ints into bits 1 thru 6 */
sr = ((sr & SR_EXL) >> 1) | ((sr & 0xfc00) >> 9);
#elif __mips == 1
/* IEC bit and shift down hardware ints into bits 1 thru 6 */
sr = (sr & SR_IEC) | ((sr & 0xfc00) >> 9);
#else
#error "CPU ISR level: unknown MIPS level for SR handling"
#endif
//printf("intlevel=%02X\n",sr);
return sr;
}
void _CPU_ISR_Set_level( unsigned32 new_level )
{
unsigned int sr, srbits;
/*
** mask off the int level bits only so we can
** preserve software int settings and FP enable
** for this thread. Note we don't force software ints
** enabled when changing level, they were turned on
** when this task was created, but may have been turned
** off since, so we'll just leave them alone.
*/
new_level &= 0xff;
mips_get_sr(sr);
#if __mips == 3
mips_set_sr( (sr & ~SR_IE) ); /* first disable ie bit (recommended) */
srbits = sr & ~(0xfc00 | SR_EXL | SR_IE);
sr = srbits | ((new_level==0)? (0xfc00 | SR_EXL | SR_IE): \
(((new_level<<9) & 0xfc00) | \
(new_level & 1)?(SR_EXL | SR_IE):0));
/*
if ( (new_level & SR_EXL) == (sr & SR_EXL) )
return;
if ( (new_level & SR_EXL) == 0 ) {
sr &= ~SR_EXL; * clear the EXL bit *
mips_set_sr(sr);
} else {
sr |= SR_EXL|SR_IE; * enable exception level *
mips_set_sr(sr); * first disable ie bit (recommended) *
}
*/
#elif __mips == 1
mips_set_sr( (sr & ~SR_IEC) );
srbits = sr & ~(0xfc00 | SR_IEC);
//printf("current sr=%08X, newlevel=%02X, srbits=%08X, ",sr,new_level,srbits);
sr = srbits | ((new_level==0)?0xfc01:( ((new_level<<9) & 0xfc00) | \
(new_level & SR_IEC)));
//printf("new sr=%08X\n",sr);
#else
#error "CPU ISR level: unknown MIPS level for SR handling"
#endif
mips_set_sr( sr );
}
/*PAGE
*
* _CPU_ISR_install_raw_handler
*
* Input parameters:
* vector - interrupt vector number
* old_handler - former ISR for this vector number
* new_handler - replacement ISR for this vector number
*
* Output parameters: NONE
*
*/
void _CPU_ISR_install_raw_handler(
unsigned32 vector,
proc_ptr new_handler,
proc_ptr *old_handler
)
{
/*
* This is where we install the interrupt handler into the "raw" interrupt
* table used by the CPU to dispatch interrupt handlers.
*
* Because all interrupts are vectored through the same exception handler
* this is not necessary on thi sport.
*/
}
/*PAGE
*
* _CPU_ISR_install_vector
*
* This kernel routine installs the RTEMS handler for the
* specified vector.
*
* Input parameters:
* vector - interrupt vector number
* old_handler - former ISR for this vector number
* new_handler - replacement ISR for this vector number
*
* Output parameters: NONE
*
*/
void _CPU_ISR_install_vector(
unsigned32 vector,
proc_ptr new_handler,
proc_ptr *old_handler
)
{
*old_handler = _ISR_Vector_table[ vector ];
/*
* If the interrupt vector table is a table of pointer to isr entry
* points, then we need to install the appropriate RTEMS interrupt
* handler for this vector number.
*/
_CPU_ISR_install_raw_handler( vector, _ISR_Handler, old_handler );
/*
* We put the actual user ISR address in '_ISR_vector_table'. This will
* be used by the _ISR_Handler so the user gets control.
*/
_ISR_Vector_table[ vector ] = new_handler;
}
/*PAGE
*
* _CPU_Install_interrupt_stack
*/
void _CPU_Install_interrupt_stack( void )
{
/* we don't support this yet */
}
/*PAGE
*
* _CPU_Internal_threads_Idle_thread_body
*
* NOTES:
*
* 1. This is the same as the regular CPU independent algorithm.
*
* 2. If you implement this using a "halt", "idle", or "shutdown"
* instruction, then don't forget to put it in an infinite loop.
*
* 3. Be warned. Some processors with onboard DMA have been known
* to stop the DMA if the CPU were put in IDLE mode. This might
* also be a problem with other on-chip peripherals. So use this
* hook with caution.
*/
void _CPU_Thread_Idle_body( void )
{
#if __mips == 3
for( ; ; )
asm volatile("wait"); /* use wait to enter low power mode */
#elif __mips == 1
for( ; ; )
;
#else
#error "IDLE: __mips not set to 1 or 3"
#endif
}
