[4e8de7e] | 1 | /** |
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| 2 | * @brief Clock Tick Device Driver |
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[acc25ee] | 3 | * |
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| 4 | * This routine utilizes the Decrementer Register common to the PPC family. |
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| 5 | * |
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| 6 | * The tick frequency is directly programmed to the configured number of |
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| 7 | * microseconds per tick. |
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[4e8de7e] | 8 | */ |
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| 9 | |
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| 10 | /* |
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[ad51436] | 11 | * COPYRIGHT (c) 1989-2014. |
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[acc25ee] | 12 | * On-Line Applications Research Corporation (OAR). |
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| 13 | * |
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| 14 | * The license and distribution terms for this file may in |
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| 15 | * the file LICENSE in this distribution or at |
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[c499856] | 16 | * http://www.rtems.org/license/LICENSE. |
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[acc25ee] | 17 | * |
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| 18 | * Modified to support the MPC750. |
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| 19 | * Modifications Copyright (c) 1999 Eric Valette valette@crf.canon.fr |
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| 20 | */ |
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| 21 | |
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| 22 | #include <rtems.h> |
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| 23 | #include <rtems/libio.h> |
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[4e8de7e] | 24 | #include <rtems/clockdrv.h> |
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[acc25ee] | 25 | #include <stdlib.h> /* for atexit() */ |
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| 26 | #include <assert.h> |
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| 27 | #include <libcpu/c_clock.h> |
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[3fa48ee] | 28 | #include <libcpu/cpuIdent.h> |
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| 29 | #include <libcpu/spr.h> |
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[9c325fb2] | 30 | #include <rtems/bspIo.h> /* for printk() */ |
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[5930196] | 31 | #include <libcpu/powerpc-utility.h> |
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[75acd9e] | 32 | #include <rtems/timecounter.h> |
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[9c325fb2] | 33 | |
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| 34 | #include <bspopts.h> /* for CLOCK_DRIVER_USE_FAST_IDLE */ |
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[acc25ee] | 35 | |
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[3fa48ee] | 36 | SPR_RW(BOOKE_TCR) |
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| 37 | SPR_RW(BOOKE_TSR) |
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| 38 | SPR_RW(BOOKE_DECAR) |
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| 39 | |
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[cebb89b] | 40 | extern int BSP_connect_clock_handler (void); |
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| 41 | |
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[acc25ee] | 42 | /* |
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| 43 | * Clock ticks since initialization |
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| 44 | */ |
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[66c373bf] | 45 | volatile uint32_t Clock_driver_ticks; |
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[acc25ee] | 46 | |
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| 47 | /* |
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| 48 | * This is the value programmed into the count down timer. |
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| 49 | */ |
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[d11b711] | 50 | static uint32_t Clock_Decrementer_value; |
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| 51 | |
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[75acd9e] | 52 | static struct timecounter Clock_TC; |
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| 53 | |
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| 54 | static uint32_t Clock_Get_timecount(struct timecounter *tc) |
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| 55 | { |
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| 56 | return ppc_time_base(); |
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| 57 | } |
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[acc25ee] | 58 | |
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| 59 | void clockOff(void* unused) |
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| 60 | { |
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[4e8de7e] | 61 | rtems_interrupt_level l; |
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[3fa48ee] | 62 | |
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| 63 | if ( ppc_cpu_is_bookE() ) { |
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| 64 | rtems_interrupt_disable(l); |
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| 65 | _write_BOOKE_TCR(_read_BOOKE_TCR() & ~BOOKE_TCR_DIE); |
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| 66 | rtems_interrupt_enable(l); |
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| 67 | } else { |
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[4e8de7e] | 68 | /* |
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| 69 | * Nothing to do as we cannot disable all interrupts and |
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| 70 | * the decrementer interrupt enable is MSR_EE |
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| 71 | */ |
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[3fa48ee] | 72 | } |
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[acc25ee] | 73 | } |
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[3fa48ee] | 74 | |
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[acc25ee] | 75 | void clockOn(void* unused) |
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| 76 | { |
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[4e8de7e] | 77 | rtems_interrupt_level l; |
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[3fa48ee] | 78 | |
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[acc25ee] | 79 | PPC_Set_decrementer( Clock_Decrementer_value ); |
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[3fa48ee] | 80 | |
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| 81 | if ( ppc_cpu_is_bookE() ) { |
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| 82 | _write_BOOKE_DECAR( Clock_Decrementer_value ); |
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| 83 | |
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| 84 | rtems_interrupt_disable(l); |
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| 85 | |
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| 86 | /* clear pending/stale irq */ |
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| 87 | _write_BOOKE_TSR( BOOKE_TSR_DIS ); |
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| 88 | /* enable */ |
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| 89 | _write_BOOKE_TCR( _read_BOOKE_TCR() | BOOKE_TCR_DIE ); |
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| 90 | |
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| 91 | rtems_interrupt_enable(l); |
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| 92 | |
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| 93 | } |
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[acc25ee] | 94 | } |
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| 95 | |
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[56758965] | 96 | static void clockHandler(void) |
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| 97 | { |
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[3c4d041c] | 98 | #if (CLOCK_DRIVER_USE_FAST_IDLE == 1) |
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[75acd9e] | 99 | rtems_interrupt_level level; |
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| 100 | uint32_t tb; |
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| 101 | |
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| 102 | rtems_interrupt_disable(level); |
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| 103 | |
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| 104 | tb = ppc_time_base(); |
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| 105 | rtems_timecounter_tick(); |
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| 106 | |
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| 107 | while ( |
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[e3be6915] | 108 | _Thread_Heir == _Thread_Executing |
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| 109 | && _Thread_Executing->Start.entry_point |
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[ad51436] | 110 | == (Thread_Entry) rtems_configuration_get_idle_task() |
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[75acd9e] | 111 | ) { |
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| 112 | tb += Clock_Decrementer_value; |
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| 113 | ppc_set_time_base( tb ); |
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| 114 | rtems_timecounter_tick(); |
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| 115 | } |
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[9c325fb2] | 116 | |
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[75acd9e] | 117 | rtems_interrupt_enable(level); |
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[9c325fb2] | 118 | #else |
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[75acd9e] | 119 | rtems_timecounter_tick(); |
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[9c325fb2] | 120 | #endif |
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[56758965] | 121 | } |
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| 122 | |
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| 123 | static void (*clock_handler)(void); |
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| 124 | |
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[acc25ee] | 125 | /* |
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| 126 | * Clock_isr |
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| 127 | * |
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| 128 | * This is the clock tick interrupt handler. |
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| 129 | * |
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| 130 | * Input parameters: |
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| 131 | * vector - vector number |
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| 132 | * |
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| 133 | * Output parameters: NONE |
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| 134 | * |
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| 135 | * Return values: NONE |
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| 136 | * |
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| 137 | */ |
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[d3d9ef37] | 138 | void clockIsr(void *unused) |
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[acc25ee] | 139 | { |
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[4e8de7e] | 140 | int decr; |
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| 141 | |
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[acc25ee] | 142 | /* |
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| 143 | * The driver has seen another tick. |
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| 144 | */ |
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[c984fb3] | 145 | do { |
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[4e8de7e] | 146 | register uint32_t flags; |
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| 147 | |
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| 148 | rtems_interrupt_disable(flags); |
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| 149 | __asm__ volatile ( |
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| 150 | "mfdec %0; add %0, %0, %1; mtdec %0" |
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| 151 | : "=&r"(decr) |
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| 152 | : "r"(Clock_Decrementer_value) |
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| 153 | ); |
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| 154 | rtems_interrupt_enable(flags); |
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| 155 | |
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| 156 | Clock_driver_ticks += 1; |
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| 157 | /* |
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| 158 | * Real Time Clock counter/timer is set to automatically reload. |
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| 159 | */ |
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| 160 | clock_handler(); |
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[c984fb3] | 161 | } while ( decr < 0 ); |
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[acc25ee] | 162 | } |
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| 163 | |
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[3fa48ee] | 164 | /* |
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| 165 | * Clock_isr_bookE |
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| 166 | * |
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| 167 | * This is the clock tick interrupt handler |
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| 168 | * for bookE CPUs. For efficiency reasons we |
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| 169 | * provide a separate handler rather than |
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| 170 | * checking the CPU type each time. |
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| 171 | */ |
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| 172 | void clockIsrBookE(void *unused) |
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| 173 | { |
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| 174 | /* Note: TSR bit has already been cleared in the exception handler */ |
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| 175 | |
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| 176 | /* |
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| 177 | * The driver has seen another tick. |
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| 178 | */ |
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| 179 | |
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| 180 | Clock_driver_ticks += 1; |
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| 181 | |
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| 182 | /* |
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| 183 | * Real Time Clock counter/timer is set to automatically reload. |
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| 184 | */ |
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| 185 | clock_handler(); |
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| 186 | } |
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| 187 | |
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[acc25ee] | 188 | int clockIsOn(void* unused) |
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| 189 | { |
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[4e8de7e] | 190 | uint32_t msr_value; |
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[acc25ee] | 191 | |
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[9c325fb2] | 192 | _CPU_MSR_GET( msr_value ); |
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[3fa48ee] | 193 | |
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[9c325fb2] | 194 | if ( ppc_cpu_is_bookE() && ! (_read_BOOKE_TCR() & BOOKE_TCR_DIE) ) |
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| 195 | msr_value = 0; |
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[3fa48ee] | 196 | |
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[9c325fb2] | 197 | if (msr_value & MSR_EE) return 1; |
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[3fa48ee] | 198 | |
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[9c325fb2] | 199 | return 0; |
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[acc25ee] | 200 | } |
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| 201 | |
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| 202 | /* |
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| 203 | * Clock_exit |
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| 204 | * |
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| 205 | * This routine allows the clock driver to exit by masking the interrupt and |
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| 206 | * disabling the clock's counter. |
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| 207 | */ |
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| 208 | void Clock_exit( void ) |
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| 209 | { |
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[0dd1d44] | 210 | (void) BSP_disconnect_clock_handler (); |
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[acc25ee] | 211 | } |
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[359e537] | 212 | |
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[acc25ee] | 213 | /* |
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| 214 | * Clock_initialize |
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| 215 | * |
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| 216 | * This routine initializes the clock driver. |
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| 217 | */ |
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| 218 | rtems_device_driver Clock_initialize( |
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| 219 | rtems_device_major_number major, |
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| 220 | rtems_device_minor_number minor, |
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| 221 | void *pargp |
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| 222 | ) |
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| 223 | { |
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[4e8de7e] | 224 | rtems_interrupt_level l,tcr; |
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[3fa48ee] | 225 | |
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[95273a6] | 226 | Clock_Decrementer_value = (BSP_bus_frequency/BSP_time_base_divisor)* |
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[d11b711] | 227 | rtems_configuration_get_milliseconds_per_tick(); |
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| 228 | |
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[359e537] | 229 | /* set the decrementer now, prior to installing the handler |
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[c984fb3] | 230 | * so no interrupts will happen in a while. |
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| 231 | */ |
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| 232 | PPC_Set_decrementer( (unsigned)-1 ); |
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| 233 | |
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[3fa48ee] | 234 | /* On a bookE CPU the decrementer works differently. It doesn't |
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| 235 | * count past zero but we can enable auto-reload :-) |
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| 236 | */ |
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| 237 | if ( ppc_cpu_is_bookE() ) { |
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| 238 | |
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| 239 | rtems_interrupt_disable(l); |
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| 240 | |
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[4e8de7e] | 241 | tcr = _read_BOOKE_TCR(); |
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| 242 | tcr |= BOOKE_TCR_ARE; |
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| 243 | tcr &= ~BOOKE_TCR_DIE; |
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| 244 | _write_BOOKE_TCR(tcr); |
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[3fa48ee] | 245 | |
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| 246 | rtems_interrupt_enable(l); |
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| 247 | } |
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[f7588eba] | 248 | |
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[75acd9e] | 249 | Clock_TC.tc_get_timecount = Clock_Get_timecount; |
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| 250 | Clock_TC.tc_counter_mask = 0xffffffff; |
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[aff220d] | 251 | Clock_TC.tc_frequency = (UINT64_C(1000) * BSP_bus_frequency) / BSP_time_base_divisor; |
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[75acd9e] | 252 | Clock_TC.tc_quality = RTEMS_TIMECOUNTER_QUALITY_CLOCK_DRIVER; |
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| 253 | rtems_timecounter_install(&Clock_TC); |
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| 254 | |
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[4e8de7e] | 255 | /* |
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| 256 | * If a decrementer exception was pending, it is cleared by |
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[c984fb3] | 257 | * executing the default (nop) handler at this point; |
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| 258 | * The next exception will then be taken by our clock handler. |
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| 259 | * Clock handler installation initializes the decrementer to |
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| 260 | * the correct value. |
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| 261 | */ |
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[56758965] | 262 | clock_handler = clockHandler; |
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[acc25ee] | 263 | if (!BSP_connect_clock_handler ()) { |
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| 264 | printk("Unable to initialize system clock\n"); |
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| 265 | rtems_fatal_error_occurred(1); |
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| 266 | } |
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| 267 | |
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| 268 | return RTEMS_SUCCESSFUL; |
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| 269 | } /* Clock_initialize */ |
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