sa11x0_misc.c

基于ecos的redboot

//==========================================================================
//
//      sa11x0_misc.c
//
//      HAL misc board support code for StrongARM SA11x0
//
//==========================================================================
//####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, 2001 Red Hat, Inc.
// All Rights Reserved.
// -------------------------------------------
//
//####COPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):    gthomas
// Contributors: hmt
//               Travis C. Furrer <[e-mail]>
// Date:         2000-05-08
// Purpose:      HAL board support
// Description:  Implementations of HAL board interfaces
//
//####DESCRIPTIONEND####
//
//========================================================================*/

#include <pkgconf/hal.h>
#include <pkgconf/system.h>
#include CYGBLD_HAL_PLATFORM_H

#include <cyg/infra/cyg_type.h>         // base types
#include <cyg/infra/cyg_trac.h>         // tracing macros
#include <cyg/infra/cyg_ass.h>          // assertion macros

#include <cyg/hal/hal_misc.h>           // Size constants
#include <cyg/hal/hal_io.h>             // IO macros
#include <cyg/hal/hal_arch.h>           // Register state info
#include <cyg/hal/hal_diag.h>
#include <cyg/hal/hal_intr.h>           // Interrupt names
#include <cyg/hal/hal_cache.h>          // Cache control
#include <cyg/hal/hal_sa11x0.h>         // Hardware definitions
#include <cyg/hal/hal_mm.h>             // MMap table definitions

#include <cyg/infra/diag.h>             // diag_printf

// Most initialization has already been done before we get here.
// All we do here is set up the interrupt environment.
// FIXME: some of the stuff in hal_platform_setup could be moved here.

externC void plf_hardware_init(void);

void hal_hardware_init(void)
{
    // Mask all interrupts
    *SA11X0_ICMR = 0;
     
    // Make all interrupts do IRQ and not FIQ
    // FIXME: Change this if you use FIQs.
    *SA11X0_ICLR = 0;
     
    // Prevent masked interrupts from bringing us out of idle mode
    *SA11X0_ICCR = 1;

    // Disable all GPIO interrupt sources
    *SA11X0_GPIO_RISING_EDGE_DETECT = 0;
    *SA11X0_GPIO_FALLING_EDGE_DETECT = 0;
    *SA11X0_GPIO_EDGE_DETECT_STATUS = 0x0FFFFFFF;

    // Perform any platform specific initializations
    plf_hardware_init();

    // Let the "OS" counter run
    *SA11X0_OSCR = 0;
    *SA11X0_OSMR0 = 0;

    // Set up eCos/ROM interfaces
    hal_if_init();

    // Enable caches
    HAL_DCACHE_ENABLE();
    HAL_ICACHE_ENABLE();
}

// -------------------------------------------------------------------------
static cyg_uint32  clock_period;

void hal_clock_initialize(cyg_uint32 period)
{
    // Load match value
    *SA11X0_OSMR0 = period;
    clock_period = period;

    // Start the counter
    *SA11X0_OSCR = 0;

    // Clear any pending interrupt
    *SA11X0_OSSR = SA11X0_OSSR_TIMER0;

    // Enable timer 0 interrupt    
    *SA11X0_OIER |= SA11X0_OIER_TIMER0;

    // Unmask timer 0 interrupt
    HAL_INTERRUPT_UNMASK( CYGNUM_HAL_INTERRUPT_TIMER0 );

    // That's all.
}

// This routine is called during a clock interrupt.

// Define this if you want to ensure that the clock is perfect (i.e. does
// not drift).  One reason to leave it turned off is that it costs some
// us per system clock interrupt for this maintenance.
#undef COMPENSATE_FOR_CLOCK_DRIFT

void hal_clock_reset(cyg_uint32 vector, cyg_uint32 period)
{
#ifdef COMPENSATE_FOR_CLOCK_DRIFT
    cyg_uint32 next = *SA11X0_OSMR0 + period;    // Next interrupt time
    *SA11X0_OSSR = SA11X0_OSSR_TIMER0;           // Clear any pending interrupt
    *SA11X0_OSMR0 = next;                        // Load new match value
    {
        cyg_uint32 ctr = *SA11X0_OSCR;
        clock_period = next - ctr;
        if ((clock_period - 1) >= period) {      // Adjust for missed interrupts
            *SA11X0_OSMR0 = ctr + period;
            *SA11X0_OSSR = SA11X0_OSSR_TIMER0;   // Clear pending interrupt
            clock_period = period;
        }
    }
#else
    *SA11X0_OSMR0 = *SA11X0_OSCR + period;       // Load new match value
    *SA11X0_OSSR = SA11X0_OSSR_TIMER0;           // Clear any pending interrupt
#endif
}

// Read the current value of the clock, returning the number of hardware
// "ticks" that have occurred (i.e. how far away the current value is from
// the start)

// Note: The "contract" for this function is that the value is the number
// of hardware clocks that have happened since the last interrupt (i.e.
// when it was reset).  This value is used to measure interrupt latencies.
// However, since the hardware counter runs freely, this routine computes
// the difference between the current clock period and the number of hardware
// ticks left before the next timer interrupt.
void hal_clock_read(cyg_uint32 *pvalue)
{
    int orig;
    HAL_DISABLE_INTERRUPTS(orig);
    *pvalue = clock_period + *SA11X0_OSCR - *SA11X0_OSMR0;
    HAL_RESTORE_INTERRUPTS(orig);

}

//
// Delay for some number of micro-seconds
//
void hal_delay_us(cyg_int32 usecs)
{
    cyg_uint32 val = 0;
    cyg_uint32 ctr = *SA11X0_OSCR;
    while (usecs-- > 0) {
        do {
            if (ctr != *SA11X0_OSCR) {
                val += 271267;          // 271267ps (3.6865Mhz -> 271.267ns)
                ++ctr;
            }
        } while (val < 1000000);
        val -= 1000000;
    }
}

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

// This routine is called to respond to a hardware interrupt (IRQ).  It
// should interrogate the hardware and return the IRQ vector number.
int hal_IRQ_handler(void)
{
    cyg_uint32 sources, index;

#ifdef HAL_EXTENDED_IRQ_HANDLER
    // Use platform specific IRQ handler, if defined
    // Note: this macro should do a 'return' with the appropriate
    // interrupt number if such an extended interrupt exists.  The
    // assumption is that the line after the macro starts 'normal' processing.
    HAL_EXTENDED_IRQ_HANDLER(index);
#endif

#if 0 // test FIQ and print alert if active - really for debugging
    sources = *SA11X0_ICFP;
    if ( 0 != sources )
        diag_printf( "FIQ source active!!! - fiqstatus %08x irqstatus %08x\n",
                     sources, *SA11X0_ICIP );
    else
#endif // Scan FIQ sources also

    sources = *SA11X0_ICIP;

// FIXME
// if we come to support FIQ properly...
//    if ( 0 == sources )
//        sources = *SA11X0_ICFP;

    // Nothing wrong with scanning them in any order we choose...
    // So here we try to make the serial devices steal fewer cycles.
    // So, knowing this is an ARM:
    if ( sources & 0xff0000 )
        index = 16;
    else if ( sources & 0xff00 )
        index = 8;
    else if ( sources & 0xff )
        index = 0;
    else // if ( sources & 0xff000000 )
        index = 24;

    do {
        if ( (1 << index) & sources ) {
            if (index == CYGNUM_HAL_INTERRUPT_GPIO) {
                // Special case of GPIO cascade.  Search for lowest set bit
                sources = *SA11X0_GPIO_EDGE_DETECT_STATUS & 0x0FFFF800;
                index = 11;
                do {
                    if (sources & (1 << index)) {
                        index += 32;
                        break;
                    }
                    index++;
                } while (index < 28);
            }
            return index;
        }
      index++;
    } while ( index & 7 );
    
    return CYGNUM_HAL_INTERRUPT_NONE; // This shouldn't happen!