/**
* @file
*
* @brief MIPS CPU Dependent Source
*/
/*
* 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) 1989-2012.
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/system.h>
#include <rtems/score/isr.h>
#include <rtems/score/wkspace.h>
#if CPU_HARDWARE_FP
Context_Control_fp _CPU_Null_fp_context;
#endif
/*
** Exception stack frame pointer used in cpu_asm to pass the exception stack frame
** address to the context switch code.
*/
#if (__mips == 1) || (__mips == 32)
typedef uint32_t ESF_PTR_TYPE;
#elif (__mips == 3)
typedef uint64_t ESF_PTR_TYPE;
#else
#error "unknown MIPS ISA"
#endif
ESF_PTR_TYPE __exceptionStackFrame = 0;
/* _CPU_Initialize
*
* This routine performs processor dependent initialization.
*
* thread_dispatch - address of dispatching routine
*/
void _CPU_Initialize(void)
{
/*
* 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.
*/
#if CPU_HARDWARE_FP
/* FP context initialization support goes here */
_CPU_Null_fp_context.fpcs = 0x1000000; /* Set FS flag in floating point coprocessor
control register to prevent underflow and
inexact exceptions */
#endif
}
uint32_t _CPU_ISR_Get_level( void )
{
unsigned int sr;
mips_get_sr(sr);
/* printf("current sr=%08X, ",sr); */
#if (__mips == 3) || (__mips == 32)
/* IE bit and shift down hardware ints into bits 1 thru 6 */
sr = (sr & SR_IE) | ((sr & mips_interrupt_mask()) >> 9);
#elif __mips == 1
/* IEC bit and shift down hardware ints into bits 1 thru 6 */
sr = (sr & SR_IEC) | ((sr & mips_interrupt_mask()) >> 9);
#else
#error "CPU ISR level: unknown MIPS level for SR handling"
#endif
return sr;
}
void _CPU_ISR_Set_level( uint32_t 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 == 32)
mips_set_sr( (sr & ~SR_IE) ); /* first disable ie bit (recommended) */
srbits = sr & ~(0xfc00 | SR_IE);
sr = srbits | ((new_level==0)? (mips_interrupt_mask() | SR_IE): \
(((new_level<<9) & mips_interrupt_mask()) | \
((new_level & 1)?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);
sr = srbits | ((new_level==0)?0xfc01:( ((new_level<<9) & 0xfc00) | \
(new_level & SR_IEC)));
#else
#error "CPU ISR level: unknown MIPS level for SR handling"
#endif
mips_set_sr( sr );
}
void _CPU_Install_interrupt_stack( void )
{
/* we don't support this yet */
}
void _CPU_Context_Initialize(
Context_Control *the_context,
uintptr_t *stack_base,
uint32_t size,
uint32_t new_level,
void *entry_point,
bool is_fp,
void *tls_area
)
{
uintptr_t stack_tmp;
__MIPS_REGISTER_TYPE intlvl = new_level & 0xff;
__MIPS_REGISTER_TYPE c0_sr;
stack_tmp = (uintptr_t)stack_base;
stack_tmp += ((size) - CPU_STACK_ALIGNMENT);
stack_tmp &= (__MIPS_REGISTER_TYPE) ~(CPU_STACK_ALIGNMENT - 1);
the_context->sp = (__MIPS_REGISTER_TYPE) stack_tmp;
the_context->fp = (__MIPS_REGISTER_TYPE) stack_tmp;
the_context->ra = (__MIPS_REGISTER_TYPE) (uintptr_t)entry_point;
c0_sr =
((intlvl==0)? (mips_interrupt_mask() | 0x300 | _INTON):
( ((intlvl<<9) & mips_interrupt_mask()) | 0x300 |
((intlvl & 1)?_INTON:0)) ) |
SR_CU0 | _EXTRABITS;
#if MIPS_HAS_FPU == 1
if ( is_fp ) {
c0_sr |= SR_CU1;
}
#endif
the_context->c0_sr = c0_sr;
}
/*
* _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( uintptr_t ignored )
{
#if (__mips == 3) || (__mips == 32)
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
}
