/**

  * $Id$

  * 

  * SH4 Timer/Clock peripheral modules (CPG, TMU, RTC), combined together to

  * keep things simple (they intertwine a bit).

  *

  * Copyright (c) 2005 Nathan Keynes.

  *

  * This program 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 Software Foundation; either version 2 of the License, or

  * (at your option) any later version.

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  */

 #include <assert.h>

 #include "lxdream.h"

 #include "mem.h"

 #include "clock.h"

 #include "eventq.h"

 #include "sh4/sh4core.h"

 #include "sh4/sh4mmio.h"

 #include "sh4/intc.h"

 /********************************* CPG *************************************/

 /* This is the base clock from which all other clocks are derived. 

  * Note: The real clock runs at 33Mhz, which is multiplied by the PLL to

  * run the instruction clock at 200Mhz. For sake of simplicity/precision,

  * we instead use 200Mhz as the base rate and divide everything down instead.

  **/

 uint32_t sh4_input_freq = SH4_BASE_RATE;

 uint32_t sh4_cpu_multiplier = 2000; /* = 0.5 * frequency */

 uint32_t sh4_cpu_freq = SH4_BASE_RATE;

 uint32_t sh4_bus_freq = SH4_BASE_RATE / 2;

 uint32_t sh4_peripheral_freq = SH4_BASE_RATE / 4;

 uint32_t sh4_cpu_period = 1000 / SH4_BASE_RATE; /* in nanoseconds */

 uint32_t sh4_bus_period = 2* 1000 / SH4_BASE_RATE;

 uint32_t sh4_peripheral_period = 4 * 2000 / SH4_BASE_RATE;

 int32_t mmio_region_CPG_read( uint32_t reg )

 {

     return MMIO_READ( CPG, reg );

 }

 /* CPU + bus dividers (note officially only the first 6 values are valid) */

 int ifc_divider[8] = { 1, 2, 3, 4, 5, 8, 8, 8 };

 /* Peripheral clock dividers (only first 5 are officially valid) */

 int pfc_divider[8] = { 2, 3, 4, 6, 8, 8, 8, 8 };

 void mmio_region_CPG_write( uint32_t reg, uint32_t val )

 {

     uint32_t div;

     uint32_t primary_clock = sh4_input_freq;

     switch( reg ) {

     case FRQCR: /* Frequency control */

         if( (val & FRQCR_PLL1EN) == 0 )

             primary_clock /= 6;

         div = ifc_divider[(val >> 6) & 0x07];

         sh4_cpu_freq = primary_clock / div;

         sh4_cpu_period = sh4_cpu_multiplier * div / sh4_input_freq;

         div = ifc_divider[(val >> 3) & 0x07];

         sh4_bus_freq = primary_clock / div;

         sh4_bus_period = 1000 * div / sh4_input_freq;

         div = pfc_divider[val & 0x07];

         sh4_peripheral_freq = primary_clock / div;

         sh4_peripheral_period = 1000 * div / sh4_input_freq;

         /* Update everything that depends on the peripheral frequency */

         SCIF_update_line_speed();

         break;

     case WTCSR: /* Watchdog timer */

         break;

     }

     MMIO_WRITE( CPG, reg, val );

 }

 /**

  * We don't really know what the default reset value is as it's determined

  * by the mode select pins. This is the standard value that the BIOS sets,

  * however, so it works for now.

  */

 void CPG_reset( )

 {

     mmio_region_CPG_write( FRQCR, 0x0E0A );

 }

 /********************************** RTC *************************************/

 uint32_t rtc_output_period;

 int32_t mmio_region_RTC_read( uint32_t reg )

 {

     return MMIO_READ( RTC, reg );

 }

 void mmio_region_RTC_write( uint32_t reg, uint32_t val )

 {

     MMIO_WRITE( RTC, reg, val );

 }

 /********************************** TMU *************************************/

 #define TMU_IS_RUNNING(timer)  (MMIO_READ(TMU,TSTR) & (1<<timer))

 uint32_t TMU_count( int timer, uint32_t nanosecs );

 void TMU_event_callback( int eventid )

 {

     TMU_count( eventid - EVENT_TMU0, sh4r.slice_cycle );

 }

 void TMU_init(void)

 {

     register_event_callback( EVENT_TMU0, TMU_event_callback );

     register_event_callback( EVENT_TMU1, TMU_event_callback );

     register_event_callback( EVENT_TMU2, TMU_event_callback );

 }    

 #define TCR_ICPF 0x0200

 #define TCR_UNF  0x0100

 #define TCR_UNIE 0x0020

 #define TCR_IRQ_ACTIVE (TCR_UNF|TCR_UNIE)

 struct TMU_timer {

     uint32_t timer_period;

     uint32_t timer_remainder; /* left-over cycles from last count */

     uint32_t timer_run; /* cycles already run from this slice */

 };

 static struct TMU_timer TMU_timers[3];

 int32_t mmio_region_TMU_read( uint32_t reg )

 {

     switch( reg ) {

     case TCNT0:

         TMU_count( 0, sh4r.slice_cycle );

         break;

     case TCNT1:

         TMU_count( 1, sh4r.slice_cycle );

         break;

     case TCNT2:

         TMU_count( 2, sh4r.slice_cycle );

         break;

     }

     return MMIO_READ( TMU, reg );

 }

 void TMU_set_timer_control( int timer,  int tcr )

 {

     uint32_t period = 1;

     uint32_t oldtcr = MMIO_READ( TMU, TCR0 + (12*timer) );

     if( (oldtcr & TCR_UNF) == 0 ) {

         tcr = tcr & (~TCR_UNF);

     } else {

         if( ((oldtcr & TCR_UNIE) == 0) && 

                 (tcr & TCR_IRQ_ACTIVE) == TCR_IRQ_ACTIVE ) {

             intc_raise_interrupt( INT_TMU_TUNI0 + timer );

         } else if( (oldtcr & TCR_UNIE) != 0 && 

                 (tcr & TCR_IRQ_ACTIVE) != TCR_IRQ_ACTIVE ) {

             intc_clear_interrupt( INT_TMU_TUNI0 + timer );

         }

     }

     switch( tcr & 0x07 ) {

     case 0:

         period = sh4_peripheral_period << 2 ;

         break;

     case 1: 

         period = sh4_peripheral_period << 4;

         break;

     case 2:

         period = sh4_peripheral_period << 6;

         break;

     case 3: 

         period = sh4_peripheral_period << 8;

         break;

     case 4:

         period = sh4_peripheral_period << 10;

         break;

     case 5:

         /* Illegal value. */

         ERROR( "TMU %d period set to illegal value (5)", timer );

         period = sh4_peripheral_period << 12; /* for something to do */

         break;

     case 6:

         period = rtc_output_period;

         break;

     case 7:

         /* External clock... Hrm? */

         period = sh4_peripheral_period; /* I dunno... */

         break;

     }

     TMU_timers[timer].timer_period = period;

     MMIO_WRITE( TMU, TCR0 + (12*timer), tcr );

 }

 void TMU_schedule_timer( int timer )

 {

     uint64_t duration = (uint64_t)((uint32_t)(MMIO_READ( TMU, TCNT0 + 12*timer )+1)) * 

     (uint64_t)TMU_timers[timer].timer_period - TMU_timers[timer].timer_remainder;

     event_schedule_long( EVENT_TMU0+timer, (uint32_t)(duration / 1000000000), 

                          (uint32_t)(duration % 1000000000) );

 }

 void TMU_start( int timer )

 {

     TMU_timers[timer].timer_run = sh4r.slice_cycle;

     TMU_timers[timer].timer_remainder = 0;

     TMU_schedule_timer( timer );

 }

 /**

  * Stop the given timer. Run it up to the current time and leave it there.

  */

 void TMU_stop( int timer )

 {

     TMU_count( timer, sh4r.slice_cycle );

     event_cancel( EVENT_TMU0+timer );

 }

 /**

  * Count the specified timer for a given number of nanoseconds.

  */

 uint32_t TMU_count( int timer, uint32_t nanosecs ) 

 {

     uint32_t run_ns = nanosecs + TMU_timers[timer].timer_remainder -

     TMU_timers[timer].timer_run;

     TMU_timers[timer].timer_remainder = 

         run_ns % TMU_timers[timer].timer_period;

     TMU_timers[timer].timer_run = nanosecs;

     uint32_t count = run_ns / TMU_timers[timer].timer_period;

     uint32_t value = MMIO_READ( TMU, TCNT0 + 12*timer );

     uint32_t reset = MMIO_READ( TMU, TCOR0 + 12*timer );

     if( count > value ) {

         uint32_t tcr = MMIO_READ( TMU, TCR0 + 12*timer );

         tcr |= TCR_UNF;

         count -= value;

         value = reset - (count % reset) + 1;

         MMIO_WRITE( TMU, TCR0 + 12*timer, tcr );

         if( tcr & TCR_UNIE ) 

             intc_raise_interrupt( INT_TMU_TUNI0 + timer );

         MMIO_WRITE( TMU, TCNT0 + 12*timer, value );

         TMU_schedule_timer(timer);

     } else {

         value -= count;

         MMIO_WRITE( TMU, TCNT0 + 12*timer, value );

     }

     return value;

 }

 void mmio_region_TMU_write( uint32_t reg, uint32_t val )

 {

     uint32_t oldval;

     int i;

     switch( reg ) {

     case TSTR:

         oldval = MMIO_READ( TMU, TSTR );

         for( i=0; i<3; i++ ) {

             uint32_t tmp = 1<<i;

             if( (oldval & tmp) != 0 && (val&tmp) == 0  )

                 TMU_stop(i);

             else if( (oldval&tmp) == 0 && (val&tmp) != 0 )

                 TMU_start(i);

         }

         break;

     case TCR0:

         TMU_set_timer_control( 0, val );

         return;

     case TCR1:

         TMU_set_timer_control( 1, val );

         return;

     case TCR2:

         TMU_set_timer_control( 2, val );

         return;

     case TCNT0:

         MMIO_WRITE( TMU, reg, val );

         if( TMU_IS_RUNNING(0) ) { // reschedule

             TMU_timers[0].timer_run = sh4r.slice_cycle;

             TMU_schedule_timer( 0 );

         }

         return;

     case TCNT1:

         MMIO_WRITE( TMU, reg, val );

         if( TMU_IS_RUNNING(1) ) { // reschedule

             TMU_timers[1].timer_run = sh4r.slice_cycle;

             TMU_schedule_timer( 1 );

         }

         return;

     case TCNT2:

         MMIO_WRITE( TMU, reg, val );

         if( TMU_IS_RUNNING(2) ) { // reschedule

             TMU_timers[2].timer_run = sh4r.slice_cycle;

             TMU_schedule_timer( 2 );

         }

         return;

     }

     MMIO_WRITE( TMU, reg, val );

 }

 void TMU_count_all( uint32_t nanosecs )

 {

     int tcr = MMIO_READ( TMU, TSTR );

     if( tcr & 0x01 ) {

         TMU_count( 0, nanosecs );

     }

     if( tcr & 0x02 ) {

         TMU_count( 1, nanosecs );

     }

     if( tcr & 0x04 ) {

         TMU_count( 2, nanosecs );

     }

 }

 void TMU_run_slice( uint32_t nanosecs )

 {

     TMU_count_all( nanosecs );

     TMU_timers[0].timer_run = 0;

     TMU_timers[1].timer_run = 0;

     TMU_timers[2].timer_run = 0;

 }

 void TMU_update_clocks()

 {

     TMU_set_timer_control( 0, MMIO_READ( TMU, TCR0 ) );

     TMU_set_timer_control( 1, MMIO_READ( TMU, TCR1 ) );

     TMU_set_timer_control( 2, MMIO_READ( TMU, TCR2 ) );

 }

 void TMU_reset( )

 {

     TMU_timers[0].timer_remainder = 0;

     TMU_timers[0].timer_run = 0;

     TMU_timers[1].timer_remainder = 0;

     TMU_timers[1].timer_run = 0;

     TMU_timers[2].timer_remainder = 0;

     TMU_timers[2].timer_run = 0;

     TMU_update_clocks();

 }

 void TMU_save_state( FILE *f ) {

     fwrite( &TMU_timers, sizeof(TMU_timers), 1, f );

 }

 int TMU_load_state( FILE *f ) 

 {

     fread( &TMU_timers, sizeof(TMU_timers), 1, f );

     return 0;

 }