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//==========================================================================

//

//      drv_api.c

//

//      Driver API for non-kernel configurations

//

//==========================================================================

// ####ECOSGPLCOPYRIGHTBEGIN####                                            

// -------------------------------------------                              

// This file is part of eCos, the Embedded Configurable Operating System.   

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.

//

// eCos is free software; you can redistribute it and/or modify it under    

// the terms of the GNU General Public License as published by the Free     

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// version.                                                                 

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// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License    

// for more details.                                                        

//

// You should have received a copy of the GNU General Public License        

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//

// As a special exception, if other files instantiate templates or use      

// macros or inline functions from this file, or you compile this file      

// and link it with other works to produce a work based on this file,       

// this file does not by itself cause the resulting work to be covered by   

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// General Public License v2.                                               

//

// This exception does not invalidate any other reasons why a work based    

// on this file might be covered by the GNU General Public License.         

// -------------------------------------------                              

// ####ECOSGPLCOPYRIGHTEND####                                              

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):   Nick Garnett

// Date:        1999-02-24

// Purpose:     Driver API for non-kernel configurations

// Description: These functions are used to support drivers when the kernel

//              is not present.

//              

//              

//

//####DESCRIPTIONEND####

//

//==========================================================================

#include <pkgconf/system.h>

#ifndef CYGPKG_KERNEL

#include <cyg/infra/cyg_type.h>

#include <cyg/infra/cyg_trac.h>

#include <cyg/infra/cyg_ass.h>

#include <pkgconf/hal.h>

#include <cyg/hal/drv_api.h>

#include <cyg/hal/hal_arch.h>

#include <cyg/hal/hal_intr.h>

//--------------------------------------------------------------------------

// Statics

static volatile cyg_int32 isr_disable_counter = 1;  // ISR disable counter

static CYG_INTERRUPT_STATE isr_disable_state;

volatile cyg_int32 dsr_disable_counter  // DSR disable counter

                      CYGBLD_ATTRIB_ASM_ALIAS( cyg_scheduler_sched_lock );

static cyg_interrupt* volatile dsr_list;        // List of pending DSRs

#ifdef CYGIMP_HAL_COMMON_INTERRUPTS_CHAIN

cyg_interrupt *chain_list[CYGNUM_HAL_ISR_COUNT];

#endif

//--------------------------------------------------------------------------

// DSR handling functions.

// post_dsr() places a DSR on the list of DSRs to be called.

// call_dsrs() calls the DSRs.

static void post_dsr( cyg_interrupt *intr )

{

    CYG_INTERRUPT_STATE old_intr;

    CYG_REPORT_FUNCTION();

    HAL_DISABLE_INTERRUPTS(old_intr);

    if( intr->dsr_count++ == 0 )

    {

        intr->next_dsr = dsr_list;

        dsr_list = intr;

    }

    HAL_RESTORE_INTERRUPTS(old_intr);

    CYG_REPORT_RETURN();

}

static void call_dsrs(void)

{

    CYG_REPORT_FUNCTION();

    while( dsr_list != NULL )

    {

        cyg_interrupt *intr;

        cyg_int32 count;

        CYG_INTERRUPT_STATE old_intr;

        HAL_DISABLE_INTERRUPTS(old_intr);

        intr = dsr_list;

        dsr_list = intr->next_dsr;

        count = intr->dsr_count;

        intr->dsr_count = 0;

        HAL_RESTORE_INTERRUPTS(old_intr);

        intr->dsr( intr->vector, count, (CYG_ADDRWORD)intr->data );

    }

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// This is referenced from the HAL, although it does not actually get called.

externC void

cyg_interrupt_call_pending_DSRs(void)

{

    call_dsrs();

}

//--------------------------------------------------------------------------

// This is called from springboard ISRs in some HALs.

externC void

cyg_interrupt_post_dsr(CYG_ADDRWORD data)

{

  cyg_interrupt * intr = (cyg_interrupt *)data;

  post_dsr(intr);

}

//--------------------------------------------------------------------------

// Interrupt end function called from HAL VSR to tidy up. This is where

// DSRs will be called if necessary.

externC void

interrupt_end(

    cyg_uint32          isr_ret,

    cyg_interrupt       *intr,

    HAL_SavedRegisters  *regs

    )

{

    CYG_REPORT_FUNCTION();

#ifndef CYGIMP_HAL_COMMON_INTERRUPTS_CHAIN

    // Only do this if we are in a non-chained configuration.

    // If we are chained, then chain_isr will do the DSR

    // posting.

    if( isr_ret & CYG_ISR_CALL_DSR && intr != NULL ) post_dsr(intr);

#endif

    if( dsr_disable_counter == 0 ) call_dsrs();

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// ISR for handling chained interrupts.

#ifdef CYGIMP_HAL_COMMON_INTERRUPTS_CHAIN

cyg_uint32 chain_isr(cyg_vector_t vector, CYG_ADDRWORD data)

{

    cyg_interrupt *p = *(cyg_interrupt **)data;

    register cyg_uint32 isr_ret = 0;

    register cyg_uint32 isr_chain_ret = 0;

    CYG_REPORT_FUNCTION();

    while( p != NULL )

    {

        if( p->vector == vector )

        {

            isr_ret = p->isr(vector, p->data);

            isr_chain_ret |= isr_ret;

            if( isr_ret & CYG_ISR_CALL_DSR ) post_dsr(p);

            if( isr_ret & CYG_ISR_HANDLED ) break;

        }

        p = p->next;

    }

#ifdef HAL_DEFAULT_ISR

    if( (isr_chain_ret & (CYG_ISR_CALL_DSR|CYG_ISR_HANDLED)) == 0 )

    {

        // If we finished the loop for some reason other than that an

        // ISR has handled the interrupt, call any default ISR to either

        // report the spurious interrupt, or do some other HAL level processing

        // such as GDB interrupt detection etc.

        HAL_DEFAULT_ISR( vector, 0 );

    }

#endif    

    CYG_REPORT_RETURN();

    return isr_ret & CYG_ISR_CALL_DSR;

}

#endif

//--------------------------------------------------------------------------

// ISR lock. This disables interrupts and keeps a count of the number

// times it has been called.

externC void cyg_drv_isr_lock()

{

    CYG_REPORT_FUNCTION();

    if( isr_disable_counter == 0 )

        HAL_DISABLE_INTERRUPTS(isr_disable_state);

    CYG_ASSERT( isr_disable_counter >= 0 , "Disable counter negative");

    isr_disable_counter++;

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// Unlock ISRs. This decrements the count and re-enables interrupts if it

// goes zero.

externC void cyg_drv_isr_unlock()

{

    CYG_REPORT_FUNCTION();

    CYG_ASSERT( isr_disable_counter > 0 , "Disable counter not greater than zero");

    isr_disable_counter--;

    if ( isr_disable_counter == 0 )

    {

        HAL_RESTORE_INTERRUPTS(isr_disable_state);

    }

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// Lock DSR lock. Simply increment the counter.

externC void cyg_drv_dsr_lock()

{

    CYG_REPORT_FUNCTION();

    dsr_disable_counter++;

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// Unlock DSR lock. If the counter is about to go zero, call any pending

// DSRs and then zero the counter.

externC void cyg_drv_dsr_unlock()

{

    CYG_REPORT_FUNCTION();

    do

    {

        if( dsr_disable_counter == 1 )

        {

            call_dsrs();

        }

        HAL_REORDER_BARRIER();

        dsr_disable_counter = 0;

        HAL_REORDER_BARRIER();

        // Check that no DSRs have been posted between calling

        // call_dsrs() and zeroing dsr_disable_counter. If so,

        // loop back and call them.

        if( dsr_list != NULL )

        {

            dsr_disable_counter = 1;

            continue;

        }

        CYG_REPORT_RETURN();

        return;

    } while(1);

    CYG_FAIL( "Should not be executed" );

}

//--------------------------------------------------------------------------

// Initialize a mutex.

externC void cyg_drv_mutex_init( cyg_drv_mutex_t *mutex )

{

    CYG_REPORT_FUNCTION();

    mutex->lock = 0;

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// Destroy a mutex.

externC void cyg_drv_mutex_destroy( cyg_drv_mutex_t *mutex )

{

    CYG_REPORT_FUNCTION();

    mutex->lock = -1;

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// Lock a mutex. We check that we are not trying to lock a locked or

// destroyed mutex and if not, set it locked.

externC cyg_bool_t cyg_drv_mutex_lock( cyg_drv_mutex_t *mutex )

{

    CYG_REPORT_FUNCTION();

    CYG_ASSERT( mutex->lock == 0 , "Trying to lock locked mutex");

    mutex->lock = 1;

    CYG_REPORT_RETURN();

    return true;

}

//--------------------------------------------------------------------------

// Attempt to claim a mutex, and return if it cannot be.

externC cyg_bool_t cyg_drv_mutex_trylock( cyg_drv_mutex_t *mutex )

{

    cyg_bool_t result = true;

    CYG_REPORT_FUNCTION();

    if( mutex->lock == 1 ) result = false;

    mutex->lock = 1;

    CYG_REPORT_RETURN();

    return result;

}

//--------------------------------------------------------------------------

// Unlock a mutex. We check that the mutex is actually locked before doing

// this.

externC void cyg_drv_mutex_unlock( cyg_drv_mutex_t *mutex )

{

    CYG_REPORT_FUNCTION();

    CYG_ASSERT( mutex->lock == 1 , "Trying to unlock unlocked mutex");

    mutex->lock = 0;

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// Release all threads waiting for the mutex.

// This is really for threads, so we do nothing here.

externC void cyg_drv_mutex_release( cyg_drv_mutex_t *mutex )

{

    CYG_REPORT_FUNCTION();

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// Initialized a condition variable.

externC void cyg_drv_cond_init( cyg_drv_cond_t  *cond, cyg_drv_mutex_t *mutex )

{

    CYG_REPORT_FUNCTION();

    cond->wait = 0;

    cond->mutex = mutex;

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// Destroy a condition variable.

externC void cyg_drv_cond_destroy( cyg_drv_cond_t  *cond )

{

    CYG_REPORT_FUNCTION();

    cond->wait = -1;

    cond->mutex = NULL;

    CYG_REPORT_RETURN();

}

// -------------------------------------------------------------------------

// Wait for a condition variable to be signalled. We simply busy wait

// polling the condition variable's wait member until a DSR sets it to

// 0.  Note that the semantics of condition variables means that the

// wakeup only happens if there is a thread actually waiting on the CV

// when the signal is sent.

externC cyg_bool cyg_drv_cond_wait( cyg_drv_cond_t *cond )

{

    CYG_REPORT_FUNCTION();

    CYG_ASSERT( cond->mutex != NULL, "Uninitialized condition variable");

    CYG_ASSERT( cond->mutex->lock, "Mutex not locked");

    cyg_drv_dsr_lock();

    cond->wait = 1;

    while( cond->wait == 1 )

    {

        // While looping we call call_dsrs() to service any DSRs that

        // get posted. One of these will make the call to cond_signal

        // to break us out of this loop. If we do not have the DSR

        // lock claimed, then a race condition could occur and keep us

        // stuck here forever.

        call_dsrs();

    }

    cyg_drv_dsr_unlock();

    CYG_REPORT_RETURN();

    return true;

}

//--------------------------------------------------------------------------

// Signal a condition variable. This sets the wait member to zero, which

// has no effect when there is no waiter, but will wake up any waiting

// thread.

externC void cyg_drv_cond_signal( cyg_drv_cond_t *cond )

{

    CYG_REPORT_FUNCTION();

    cond->wait = 0;

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// Broadcast to condition variable. This is exactly the same a signal since

// there can only be one waiter.

externC void cyg_drv_cond_broadcast( cyg_drv_cond_t *cond )

{

    CYG_REPORT_FUNCTION();

    cond->wait = 0;

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// Spinlock support.

// Since we can only support a single CPU in this version of the API, we only

// set and clear the lock variable to keep track of what's happening.

void cyg_drv_spinlock_init(

    cyg_drv_spinlock_t  *lock,          /* spinlock to initialize            */

    cyg_bool_t          locked          /* init locked or unlocked           */

)

{

    CYG_REPORT_FUNCTION();

    lock->lock = locked;

    CYG_REPORT_RETURN();

}

void cyg_drv_spinlock_destroy( cyg_drv_spinlock_t *lock )

{

    CYG_REPORT_FUNCTION();

    lock->lock = -1;

    CYG_REPORT_RETURN();

}

void cyg_drv_spinlock_spin( cyg_drv_spinlock_t *lock )

{

    CYG_REPORT_FUNCTION();

    CYG_ASSERT( lock->lock == 0 , "Trying to lock locked spinlock");

    lock->lock = 1;

    CYG_REPORT_RETURN();

}

void cyg_drv_spinlock_clear( cyg_drv_spinlock_t *lock )

{

    CYG_REPORT_FUNCTION();

    CYG_ASSERT( lock->lock == 1 , "Trying to clear cleared spinlock");

    lock->lock = 0;

    CYG_REPORT_RETURN();

}

cyg_bool_t cyg_drv_spinlock_try( cyg_drv_spinlock_t *lock )

{

    cyg_bool_t result = true;

    CYG_REPORT_FUNCTION();

    if( lock->lock == 1 ) result = false;

    lock->lock = 1;

    CYG_REPORT_RETURN();

    return result;

}

cyg_bool_t cyg_drv_spinlock_test( cyg_drv_spinlock_t *lock )

{

    cyg_bool_t result = true;

    CYG_REPORT_FUNCTION();

    if( lock->lock == 1 ) result = false;

    CYG_REPORT_RETURN();

    return result;

}

void cyg_drv_spinlock_spin_intsave( cyg_drv_spinlock_t *lock,

                                    cyg_addrword_t *istate )

{

    CYG_REPORT_FUNCTION();

    HAL_DISABLE_INTERRUPTS( *istate );

    lock->lock = 1;

    CYG_REPORT_RETURN();

}

void cyg_drv_spinlock_clear_intsave( cyg_drv_spinlock_t *lock,

                                     cyg_addrword_t istate )

{

    CYG_REPORT_FUNCTION();

    lock->lock = 0;

    HAL_RESTORE_INTERRUPTS( istate );

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// Create an interrupt object.

externC void cyg_drv_interrupt_create(

                     cyg_vector_t        vector,

                     cyg_priority_t      priority,

                     cyg_addrword_t      data,

                     cyg_ISR_t           *isr,

                     cyg_DSR_t           *dsr,

                     cyg_handle_t        *handle,

                     cyg_interrupt       *intr

                     )

{

    CYG_REPORT_FUNCTION();

    intr->vector        = vector;

    intr->priority      = priority;

    intr->isr           = isr;

    intr->dsr           = dsr;

    intr->data          = data;

    intr->next_dsr      = NULL;

    intr->dsr_count     = 0;

#ifdef CYGIMP_HAL_COMMON_INTERRUPTS_CHAIN

    intr->next          = NULL;

#endif    

    *handle = (cyg_handle_t)intr;

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// Delete an interrupt object. This merely ensures that it is detached from

// the vector.

externC void cyg_drv_interrupt_delete( cyg_handle_t interrupt )

{

    CYG_REPORT_FUNCTION();

    cyg_drv_interrupt_detach( interrupt );

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// 

externC void cyg_drv_interrupt_attach( cyg_handle_t interrupt )

{

    cyg_interrupt *intr = (cyg_interrupt *)interrupt;

    CYG_REPORT_FUNCTION();

    CYG_ASSERT( intr->vector >= CYGNUM_HAL_ISR_MIN, "Invalid vector");

    CYG_ASSERT( intr->vector <= CYGNUM_HAL_ISR_MAX, "Invalid vector");

    HAL_INTERRUPT_SET_LEVEL( intr->vector, intr->priority );

#ifdef CYGIMP_HAL_COMMON_INTERRUPTS_CHAIN

    CYG_ASSERT( intr->next == NULL , "cyg_interrupt already on a list");

    {

        cyg_uint32 index;

        HAL_TRANSLATE_VECTOR( intr->vector, index );

        if( chain_list[index] == NULL )

        {

            // First Interrupt on this chain, just assign it and

            // register the chain_isr with the HAL.

            chain_list[index] = intr;

            HAL_INTERRUPT_ATTACH( intr->vector, chain_isr,

                                  &chain_list[index], NULL );

        }

        else

        {

            // There are already interrupts chained, add this one into

            // the chain in priority order.

            cyg_interrupt **p = &chain_list[index];

            while( *p != NULL )

            {

                cyg_interrupt *n = *p;

                if( n->priority < intr->priority ) break;

                p = &n->next;

            }

            intr->next = *p;

            *p = intr;

        }

    }

#else

    HAL_INTERRUPT_ATTACH( intr->vector, intr->isr, intr->data, intr );

#endif    

    CYG_REPORT_RETURN();

}

//--------------------------------------------------------------------------

// Detach an interrupt from its vector.

externC void cyg_drv_interrupt_detach( cyg_handle_t interrupt )

{

    cyg_interrupt *intr = (cyg_interrupt *)interrupt;

    CYG_REPORT_FUNCTION();

    CYG_ASSERT( intr->vector >= CYGNUM_HAL_ISR_MIN, "Invalid vector");

    CYG_ASSERT( intr->vector <= CYGNUM_HAL_ISR_MAX, "Invalid vector");

#ifdef CYGIMP_HAL_COMMON_INTERRUPTS_CHAIN

    // Remove the interrupt object from the vector chain.

    {

        cyg_uint32 index;

        cyg_interrupt **p;

        HAL_TRANSLATE_VECTOR( intr->vector, index );

        p = &chain_list[index];

        while( *p != NULL )

        {

            cyg_interrupt *n = *p;

            if( n == intr )

            {

                *p = intr->next;

                break;

            }

            p = &n->next;

        }

        // If this was the last one, detach the vector.

        if( chain_list[index] == NULL )

            HAL_INTERRUPT_DETACH( intr->vector, chain_isr );

    }

#else

    HAL_INTERRUPT_DETACH( intr->vector, intr->isr );

#endif

    CYG_REPORT_RETURN();