1 | /* Clock_init() |
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2 | * |
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3 | * This routine initializes Timer 1 for an MC68302. |
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4 | * The tick frequency is 1 millisecond. |
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5 | * |
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6 | * Input parameters: NONE |
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7 | * |
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8 | * Output parameters: NONE |
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9 | * |
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10 | * COPYRIGHT (c) 1989-1999. |
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11 | * On-Line Applications Research Corporation (OAR). |
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12 | * |
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13 | * The license and distribution terms for this file may be |
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14 | * found in the file LICENSE in this distribution or at |
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15 | * http://www.OARcorp.com/rtems/license.html. |
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16 | * |
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17 | * $Id$ |
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18 | */ |
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19 | |
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20 | #include <stdlib.h> /* for atexit() */ |
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21 | |
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22 | #include <bsp.h> |
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23 | #include <rtems/libio.h> |
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24 | |
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25 | #include "m68302.h" |
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26 | |
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27 | #define CLOCK_VECTOR 137 |
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28 | |
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29 | #define TMR1_VAL ( RBIT_TMR_RST /* software reset the timer */\ |
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30 | | RBIT_TMR_ICLK_MASTER16 /* master clock divided by 16 */\ |
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31 | | RBIT_TMR_FRR /* restart timer after ref reached */\ |
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32 | | RBIT_TMR_ORI) /* enable interrupt when ref reached */ |
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33 | #define TRR1_VAL 1000 /* 1000 ticks @ 16MHz/16 |
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34 | * = 1 millisecond tick. |
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35 | */ |
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36 | |
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37 | /* |
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38 | * Clock_driver_ticks is a monotonically increasing counter of the |
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39 | * number of clock ticks since the driver was initialized. |
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40 | */ |
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41 | volatile rtems_unsigned32 Clock_driver_ticks; |
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42 | |
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43 | /* |
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44 | * Clock_isrs is the number of clock ISRs until the next invocation of |
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45 | * the RTEMS clock tick routine. The clock tick device driver |
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46 | * gets an interrupt once a millisecond and counts down until the |
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47 | * length of time between the user configured microseconds per tick |
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48 | * has passed. |
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49 | */ |
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50 | rtems_unsigned32 Clock_isrs; |
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51 | |
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52 | void Clock_exit( void ); |
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53 | |
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54 | /* |
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55 | * These are set by clock driver during its init |
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56 | */ |
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57 | |
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58 | rtems_device_major_number rtems_clock_major = ~0; |
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59 | rtems_device_minor_number rtems_clock_minor; |
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60 | |
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61 | /* |
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62 | * ISR Handler |
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63 | */ |
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64 | |
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65 | rtems_isr Clock_isr( |
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66 | rtems_vector_number vector |
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67 | ) |
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68 | { |
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69 | Clock_driver_ticks += 1; |
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70 | |
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71 | m302.reg.isr = RBIT_ISR_TIMER1; /* clear in-service bit */ |
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72 | m302.reg.ter1 = (RBIT_TER_REF | RBIT_TER_CAP); /* clear timer intr request */ |
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73 | |
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74 | if ( Clock_isrs == 1 ) { |
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75 | rtems_clock_tick(); |
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76 | Clock_isrs = BSP_Configuration.microseconds_per_tick / 1000; |
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77 | } |
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78 | else |
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79 | Clock_isrs -= 1; |
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80 | } |
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81 | |
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82 | void Install_clock( |
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83 | rtems_isr_entry clock_isr |
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84 | ) |
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85 | { |
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86 | |
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87 | Clock_driver_ticks = 0; |
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88 | Clock_isrs = BSP_Configuration.microseconds_per_tick / 1000; |
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89 | |
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90 | set_vector( clock_isr, CLOCK_VECTOR, 1 ); |
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91 | |
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92 | m302.reg.trr1 = TRR1_VAL; /* set timer reference register */ |
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93 | m302.reg.tmr1 = TMR1_VAL; /* set timer mode register & enable */ |
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94 | /* |
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95 | * Enable TIMER1 interrupts only. |
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96 | */ |
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97 | m302.reg.imr |= RBIT_IMR_TIMER1; /* set 68302 int-mask to allow ints */ |
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98 | |
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99 | atexit( Clock_exit ); |
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100 | } |
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101 | |
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102 | void Clock_exit( void ) |
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103 | { |
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104 | /* TODO: figure out what to do here */ |
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105 | /* do not restore old vector */ |
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106 | } |
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107 | |
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108 | rtems_device_driver Clock_initialize( |
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109 | rtems_device_major_number major, |
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110 | rtems_device_minor_number minor, |
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111 | void *pargp |
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112 | ) |
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113 | { |
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114 | Install_clock( Clock_isr ); |
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115 | |
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116 | /* |
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117 | * make major/minor avail to others such as shared memory driver |
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118 | */ |
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119 | |
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120 | rtems_clock_major = major; |
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121 | rtems_clock_minor = minor; |
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122 | |
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123 | return RTEMS_SUCCESSFUL; |
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124 | } |
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125 | |
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126 | rtems_device_driver Clock_control( |
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127 | rtems_device_major_number major, |
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128 | rtems_device_minor_number minor, |
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129 | void *pargp |
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130 | ) |
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131 | { |
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132 | rtems_unsigned32 isrlevel; |
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133 | rtems_libio_ioctl_args_t *args = pargp; |
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134 | |
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135 | if (args == 0) |
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136 | goto done; |
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137 | |
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138 | /* |
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139 | * This is hokey, but until we get a defined interface |
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140 | * to do this, it will just be this simple... |
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141 | */ |
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142 | |
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143 | if (args->command == rtems_build_name('I', 'S', 'R', ' ')) |
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144 | { |
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145 | Clock_isr( CLOCK_VECTOR); |
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146 | } |
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147 | else if (args->command == rtems_build_name('N', 'E', 'W', ' ')) |
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148 | { |
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149 | rtems_interrupt_disable( isrlevel ); |
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150 | (void) set_vector( args->buffer, CLOCK_VECTOR, 1 ); |
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151 | rtems_interrupt_enable( isrlevel ); |
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152 | } |
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153 | |
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154 | done: |
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155 | return RTEMS_SUCCESSFUL; |
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156 | } |
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157 | |
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