hal_if.c

Intel XScale PXA255 引导Linux的Redboot 版bootloader源代码！

//=============================================================================
//
//      hal_if.c
//
//      ROM/RAM interfacing functions
//
//=============================================================================
//####COPYRIGHTBEGIN####
//                                                                          
// -------------------------------------------                              
// The contents of this file are subject to the Red Hat eCos Public License 
// Version 1.1 (the "License"); you may not use this file except in         
// compliance with the License.  You may obtain a copy of the License at    
// http://www.redhat.com/                                                   
//                                                                          
// Software distributed under the License is distributed on an "AS IS"      
// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the 
// License for the specific language governing rights and limitations under 
// the License.                                                             
//                                                                          
// The Original Code is eCos - Embedded Configurable Operating System,      
// released September 30, 1998.                                             
//                                                                          
// The Initial Developer of the Original Code is Red Hat.                   
// Portions created by Red Hat are                                          
// Copyright (C) 1998, 1999, 2000 Red Hat, Inc.                             
// All Rights Reserved.                                                     
// -------------------------------------------                              
//                                                                          
//####COPYRIGHTEND####
//=============================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):   jskov
// Contributors:jskov
// Date:        2000-06-07
//
//####DESCRIPTIONEND####
//
//=============================================================================

#include <pkgconf/hal.h>

#ifdef CYGPKG_KERNEL
# include <pkgconf/kernel.h>
#endif

#include <cyg/infra/cyg_ass.h>          // assertions

#include <cyg/hal/hal_arch.h>           // set/restore GP

#include <cyg/hal/hal_io.h>             // IO macros
#include <cyg/hal/hal_if.h>             // our interface

#include <cyg/hal/hal_diag.h>           // Diag IO
#include <cyg/hal/hal_misc.h>           // User break

#include <cyg/hal/hal_stub.h>           // stub functionality
#include <cyg/hal/plf_stub.h>           // reset entry - FIXME, should be moved

#include <cyg/hal/hal_intr.h>           // hal_vsr_table and others


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

externC void patch_dbg_syscalls(void * vector);
externC void init_thread_syscall(void * vector);

//--------------------------------------------------------------------------
// Implementations and function wrappers for monitor services

#ifdef CYGPRI_HAL_IMPLEMENTS_IF_SERVICES
static void
delay_us(cyg_int32 usecs)
{
#ifdef CYGPKG_KERNEL
    cyg_int32 start, elapsed;
    cyg_int32 usec_ticks, slice;
    CYGARC_HAL_SAVE_GP();

    // How many ticks total we should wait for.
    usec_ticks = usecs*CYGNUM_KERNEL_COUNTERS_RTC_PERIOD;
    usec_ticks /= CYGNUM_HAL_RTC_NUMERATOR/CYGNUM_HAL_RTC_DENOMINATOR/1000;

    do {
        // Spin in slices of 1/2 the RTC period. Allows interrupts
        // time to run without messing up the algorithm. If we spun
        // for 1 period (or more) of the RTC, there'd be also problems
        // figuring out when the timer wrapped.  We may lose a tick or
        // two for each cycle but it shouldn't matter much.
        slice = usec_ticks % (CYGNUM_KERNEL_COUNTERS_RTC_PERIOD / 2);
    
        HAL_CLOCK_READ(&start);
        do {
            HAL_CLOCK_READ(&elapsed);
            elapsed = (elapsed - start); // counts up!
            if (elapsed < 0)
                elapsed += CYGNUM_KERNEL_COUNTERS_RTC_PERIOD;
        } while (elapsed < slice);

        // Adjust by elapsed, not slice, since an interrupt may have
        // been stalling us for some time.
        usec_ticks -= elapsed;
    } while (usec_ticks > 0);

    CYGARC_HAL_RESTORE_GP();
#else
#ifdef HAL_DELAY_US
    // Use a HAL feature if defined
    HAL_DELAY_US(usecs);
#else
    // If no accurate delay mechanism, just spin for a while. Having
    // an inaccurate delay is much better than no delay at all. The
    // count of 100 should mean the loop takes something resembling
    // 1us on most CPUs running between 30-100MHz [depends on how many
    // instructions this compiles to, how many dispatch units can be
    // used for the simple loop, actual CPU frequency, etc]
    while (usecs-- > 0) {
        int i;
        for (i = 0; i < 100; i++);
    }
#endif
#endif
}

static void
reset(void)
{
    CYGARC_HAL_SAVE_GP();
    // With luck, the platform defines some magic that will cause a hardware
    // reset.
    HAL_STUB_PLATFORM_RESET();

#ifdef HAL_STUB_PLATFORM_RESET_ENTRY
    // If that's not the case (above is an empty statement) there may
    // be defined an address we can jump to - and effectively
    // reinitialize the system. Not quite as good as a reset, but it
    // is often enough.
    goto *HAL_STUB_PLATFORM_RESET_ENTRY;

#else
#error " no RESET_ENTRY"
#endif

    CYGARC_HAL_RESTORE_GP();
}

// This is the system's default kill signal routine. Unless overridden
// by the application, it will cause a board reset when GDB quits the
// connection. (The user can avoid the reset by using the GDB 'detach'
// command instead of 'kill' or 'quit').
static int
kill_by_reset(int __irq_nr, void* __regs)
{
    CYGARC_HAL_SAVE_GP();

    reset();

    CYGARC_HAL_RESTORE_GP();
    return 0;
}

static int
nop_service(void)
{
    // This is the default service. It always returns false (0), and
    // _does_ not trigger any assertions. Clients must either cope
    // with the service failure or assert.
    return 0;
}

//----------------------------------
// Comm controls

#ifdef CYGNUM_HAL_VIRTUAL_VECTOR_AUX_CHANNELS
#define CYGNUM_HAL_VIRTUAL_VECTOR_NUM_CHANNELS \
  (CYGNUM_HAL_VIRTUAL_VECTOR_COMM_CHANNELS+CYGNUM_HAL_VIRTUAL_VECTOR_AUX_CHANNELS)
#else
#define CYGNUM_HAL_VIRTUAL_VECTOR_NUM_CHANNELS \
  CYGNUM_HAL_VIRTUAL_VECTOR_COMM_CHANNELS
#endif

static hal_virtual_comm_table_t comm_channels[CYGNUM_HAL_VIRTUAL_VECTOR_NUM_CHANNELS+1];

static int
set_debug_comm(int __comm_id)
{
    static int __selected_id = CYGNUM_CALL_IF_SET_COMM_ID_EMPTY;
    hal_virtual_comm_table_t* __chan;
    int interrupt_state = 0;
    int res = 1, update = 0;
    CYGARC_HAL_SAVE_GP();

    CYG_ASSERT(__comm_id >= CYGNUM_CALL_IF_SET_COMM_ID_MANGLER
               && __comm_id < CYGNUM_HAL_VIRTUAL_VECTOR_NUM_CHANNELS,
               "Invalid channel");

    switch (__comm_id) {
    case CYGNUM_CALL_IF_SET_COMM_ID_QUERY_CURRENT:
        if (__selected_id > 0)
            res = __selected_id-1;
        else if (__selected_id == 0)
            res = CYGNUM_CALL_IF_SET_COMM_ID_MANGLER;
        else 
            res = __selected_id;
        break;

    case CYGNUM_CALL_IF_SET_COMM_ID_EMPTY:
        CYGACC_CALL_IF_DEBUG_PROCS_SET(0);
        __selected_id = __comm_id;
        break;

    case CYGNUM_CALL_IF_SET_COMM_ID_MANGLER:
        __comm_id = 0;
        update = 1;
        break;

    default:
        __comm_id++;                    // skip mangler entry
        update = 1;
        break;
    }

    if (update) {
        // Find the interrupt state of the channel.
        __chan = CYGACC_CALL_IF_DEBUG_PROCS();
        if (__chan)
            interrupt_state = CYGACC_COMM_IF_CONTROL(*__chan, __COMMCTL_IRQ_DISABLE);

        __selected_id = __comm_id;
        CYGACC_CALL_IF_DEBUG_PROCS_SET(comm_channels[__comm_id]);

        // Set interrupt state on the new channel.
        __chan = CYGACC_CALL_IF_DEBUG_PROCS();
        if (interrupt_state)
            CYGACC_COMM_IF_CONTROL(*__chan, __COMMCTL_IRQ_ENABLE);
        else
            CYGACC_COMM_IF_CONTROL(*__chan, __COMMCTL_IRQ_DISABLE);
    }

    CYGARC_HAL_RESTORE_GP();
    return res;
}

static int
set_console_comm(int __comm_id)
{
    static int __selected_id = CYGNUM_CALL_IF_SET_COMM_ID_EMPTY;
    int res = 1, update = 0;
    CYGARC_HAL_SAVE_GP();

    CYG_ASSERT(__comm_id >= CYGNUM_CALL_IF_SET_COMM_ID_MANGLER
               && __comm_id < CYGNUM_HAL_VIRTUAL_VECTOR_NUM_CHANNELS,
               "Invalid channel");

    switch (__comm_id) {
    case CYGNUM_CALL_IF_SET_COMM_ID_QUERY_CURRENT:
        if (__selected_id > 0)
            res = __selected_id-1;
        else if (__selected_id == 0)
            res = CYGNUM_CALL_IF_SET_COMM_ID_MANGLER;
        else
            res = __selected_id;
        break;

    case CYGNUM_CALL_IF_SET_COMM_ID_EMPTY:
        CYGACC_CALL_IF_CONSOLE_PROCS_SET(0);
        __selected_id = __comm_id;
        break;

    case CYGNUM_CALL_IF_SET_COMM_ID_MANGLER:
        __comm_id = 0;
        update = 1;
        break;