1 | /* |
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2 | * Use the last periodic interval timer (PIT3) as the system clock. |
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3 | * |
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4 | * Author: W. Eric Norum <norume@aps.anl.gov> |
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5 | * |
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6 | * COPYRIGHT (c) 2005. |
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7 | * On-Line Applications Research Corporation (OAR). |
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8 | * |
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9 | * The license and distribution terms for this file may be |
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10 | * found in the file LICENSE in this distribution or at |
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11 | * http://www.rtems.org/license/LICENSE. |
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12 | */ |
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13 | |
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14 | #include <rtems.h> |
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15 | #include <rtems/timecounter.h> |
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16 | #include <bsp.h> |
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17 | #include <mcf5282/mcf5282.h> |
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18 | |
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19 | /* |
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20 | * CPU load counters |
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21 | * Place in static RAM so updates don't hit the SDRAM |
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22 | */ |
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23 | #define IDLE_COUNTER __SRAMBASE.idle_counter |
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24 | #define FILTERED_IDLE __SRAMBASE.filtered_idle |
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25 | #define MAX_IDLE_COUNT __SRAMBASE.max_idle_count |
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26 | #define PITC_PER_TICK __SRAMBASE.pitc_per_tick |
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27 | #define NSEC_PER_PITC __SRAMBASE.nsec_per_pitc |
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28 | #define FILTER_SHIFT 6 |
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29 | |
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30 | /* |
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31 | * Use INTC0 base |
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32 | */ |
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33 | #define CLOCK_VECTOR (64+58) |
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34 | |
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35 | static rtems_timecounter_simple uC5282_tc; |
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36 | |
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37 | static uint32_t uC5282_tc_get(rtems_timecounter_simple *tc) |
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38 | { |
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39 | return MCF5282_PIT3_PCNTR; |
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40 | } |
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41 | |
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42 | static bool uC5282_tc_is_pending(rtems_timecounter_simple *tc) |
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43 | { |
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44 | return (MCF5282_PIT3_PCSR & MCF5282_PIT_PCSR_PIF) != 0; |
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45 | } |
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46 | |
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47 | static uint32_t uC5282_tc_get_timecount(struct timecounter *tc) |
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48 | { |
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49 | return rtems_timecounter_simple_downcounter_get( |
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50 | tc, |
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51 | uC5282_tc_get, |
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52 | uC5282_tc_is_pending |
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53 | ); |
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54 | } |
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55 | |
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56 | static void uC5282_tc_at_tick(rtems_timecounter_simple *tc) |
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57 | { |
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58 | unsigned idle = IDLE_COUNTER; |
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59 | IDLE_COUNTER = 0; |
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60 | if (idle > MAX_IDLE_COUNT) |
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61 | MAX_IDLE_COUNT = idle; |
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62 | FILTERED_IDLE = idle + FILTERED_IDLE - (FILTERED_IDLE>>FILTER_SHIFT); |
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63 | MCF5282_PIT3_PCSR |= MCF5282_PIT_PCSR_PIF; |
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64 | } |
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65 | |
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66 | static void uC5282_tc_tick(void) |
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67 | { |
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68 | rtems_timecounter_simple_downcounter_tick( |
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69 | &uC5282_tc, |
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70 | uC5282_tc_get, |
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71 | uC5282_tc_at_tick |
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72 | ); |
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73 | } |
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74 | |
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75 | /* |
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76 | * Attach clock interrupt handler |
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77 | */ |
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78 | #define Clock_driver_support_install_isr( _new ) \ |
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79 | set_vector(_new, CLOCK_VECTOR, 1) |
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80 | |
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81 | /* |
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82 | * Turn off the clock |
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83 | */ |
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84 | #define Clock_driver_support_shutdown_hardware() \ |
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85 | do { \ |
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86 | MCF5282_PIT3_PCSR &= ~MCF5282_PIT_PCSR_EN; \ |
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87 | } while(0) |
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88 | |
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89 | /* |
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90 | * Set up the clock hardware |
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91 | * |
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92 | * f_pit = f_clk / 2^(preScaleCode+1) / N = 1/(us_per_tick/us_per_s) |
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93 | * |
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94 | * N = f_clk / 2^(preScaleCode+1) * us_per_tick / us_per_s |
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95 | * |
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96 | * ns_per_pit_clk = ns_per_s / (f_clk / 2^(preScaleCode+1)) |
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97 | * = ns_per_s * 2^(preScaleCode+1) / f_clk; |
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98 | */ |
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99 | #define Clock_driver_support_initialize_hardware() \ |
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100 | do { \ |
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101 | unsigned long long N; \ |
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102 | int level; \ |
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103 | int preScaleCode = 0; \ |
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104 | N = bsp_get_CPU_clock_speed(); \ |
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105 | N *= rtems_configuration_get_microseconds_per_tick(); \ |
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106 | N /= 2*1000000; /* min_prescale * us_per_s */ \ |
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107 | while ( N > 0x10000 ) { \ |
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108 | preScaleCode++; \ |
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109 | N >>= 1; \ |
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110 | } \ |
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111 | PITC_PER_TICK = N; \ |
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112 | N = 2000000000ULL << preScaleCode; \ |
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113 | N /= bsp_get_CPU_clock_speed(); \ |
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114 | NSEC_PER_PITC = N; \ |
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115 | IDLE_COUNTER = 0; \ |
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116 | FILTERED_IDLE = 0; \ |
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117 | MAX_IDLE_COUNT = 0; \ |
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118 | bsp_allocate_interrupt(PIT3_IRQ_LEVEL, PIT3_IRQ_PRIORITY); \ |
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119 | MCF5282_INTC0_ICR58 = MCF5282_INTC_ICR_IL(PIT3_IRQ_LEVEL) | \ |
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120 | MCF5282_INTC_ICR_IP(PIT3_IRQ_PRIORITY); \ |
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121 | rtems_interrupt_disable( level ); \ |
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122 | MCF5282_INTC0_IMRH &= ~MCF5282_INTC_IMRH_INT58; \ |
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123 | MCF5282_PIT3_PCSR &= ~MCF5282_PIT_PCSR_EN; \ |
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124 | rtems_interrupt_enable( level ); \ |
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125 | MCF5282_PIT3_PCSR = MCF5282_PIT_PCSR_PRE(preScaleCode) | \ |
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126 | MCF5282_PIT_PCSR_OVW | \ |
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127 | MCF5282_PIT_PCSR_PIE | \ |
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128 | MCF5282_PIT_PCSR_RLD; \ |
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129 | MCF5282_PIT3_PMR = PITC_PER_TICK - 1; \ |
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130 | MCF5282_PIT3_PCSR = MCF5282_PIT_PCSR_PRE(preScaleCode) | \ |
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131 | MCF5282_PIT_PCSR_PIE | \ |
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132 | MCF5282_PIT_PCSR_RLD | \ |
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133 | MCF5282_PIT_PCSR_EN; \ |
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134 | rtems_timecounter_simple_install( \ |
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135 | &uC5282_tc, \ |
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136 | bsp_get_CPU_clock_speed() >> (preScaleCode + 1), \ |
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137 | PITC_PER_TICK, \ |
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138 | uC5282_tc_get_timecount \ |
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139 | ); \ |
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140 | } while (0) |
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141 | |
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142 | /* |
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143 | * Provide our own version of the idle task |
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144 | */ |
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145 | void * bsp_idle_thread(uint32_t ignored) |
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146 | { |
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147 | /* Atomic increment */ |
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148 | for(;;) |
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149 | __asm__ volatile ("addq.l #1,%0"::"m"(IDLE_COUNTER)); |
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150 | } |
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151 | |
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152 | int bsp_cpu_load_percentage(void) |
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153 | { |
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154 | return MAX_IDLE_COUNT ? |
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155 | (100 - ((100 * (FILTERED_IDLE >> FILTER_SHIFT)) / MAX_IDLE_COUNT)) : |
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156 | 0; |
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157 | } |
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158 | |
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159 | #define Clock_driver_timecounter_tick() uC5282_tc_tick() |
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160 | |
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161 | #include "../../../shared/dev/clock/clockimpl.h" |
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