1 | /* ckinit.c |
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2 | * |
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3 | * This file provides a template for the clock device driver initialization. |
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4 | * |
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5 | * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994. |
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6 | * On-Line Applications Research Corporation (OAR). |
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7 | * All rights assigned to U.S. Government, 1994. |
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8 | * |
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9 | * This material may be reproduced by or for the U.S. Government pursuant |
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10 | * to the copyright license under the clause at DFARS 252.227-7013. This |
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11 | * notice must appear in all copies of this file and its derivatives. |
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12 | * |
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13 | * $Id$ |
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14 | */ |
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15 | |
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16 | #include <stdlib.h> |
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17 | |
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18 | #include <rtems.h> |
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19 | #include <bsp.h> |
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20 | #include <clockdrv.h> |
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21 | |
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22 | /* |
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23 | * The interrupt vector number associated with the clock tick device |
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24 | * driver. |
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25 | */ |
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26 | |
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27 | #define CLOCK_VECTOR 4 |
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28 | |
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29 | /* |
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30 | * Clock_driver_ticks is a monotonically increasing counter of the |
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31 | * number of clock ticks since the driver was initialized. |
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32 | */ |
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33 | volatile rtems_unsigned32 Clock_driver_ticks; |
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34 | |
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35 | /* |
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36 | * Clock_isrs is the number of clock ISRs until the next invocation of |
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37 | * the RTEMS clock tick routine. The clock tick device driver |
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38 | * gets an interrupt once a millisecond and counts down until the |
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39 | * length of time between the user configured microseconds per tick |
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40 | * has passed. |
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41 | */ |
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42 | |
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43 | rtems_unsigned32 Clock_isrs; /* ISRs until next tick */ |
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44 | |
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45 | /* |
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46 | * The previous ISR on this clock tick interrupt vector. |
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47 | */ |
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48 | |
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49 | rtems_isr_entry Old_ticker; |
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50 | |
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51 | /* |
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52 | * Clock_initialize |
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53 | * |
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54 | * Device driver entry point for clock tick driver initialization. |
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55 | */ |
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56 | |
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57 | rtems_device_driver Clock_initialize( |
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58 | rtems_device_major_number major, |
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59 | rtems_device_minor_number minor, |
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60 | void *pargp, |
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61 | rtems_id tid, |
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62 | rtems_unsigned32 *rval |
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63 | ) |
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64 | { |
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65 | Install_clock( Clock_isr ); |
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66 | } |
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67 | |
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68 | /* |
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69 | * Reinstall_clock |
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70 | * |
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71 | * Install a clock tick handler without reprogramming the chip. This |
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72 | * is used by the polling shared memory device driver. |
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73 | */ |
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74 | |
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75 | void ReInstall_clock( |
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76 | rtems_isr_entry clock_isr |
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77 | ) |
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78 | { |
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79 | rtems_unsigned32 isrlevel = 0; |
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80 | |
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81 | /* |
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82 | * Disable interrupts and install the clock ISR vector using the |
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83 | * BSP dependent set_vector routine. In the below example, the clock |
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84 | * ISR is on vector 4 and is an RTEMS interrupt. |
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85 | */ |
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86 | |
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87 | rtems_interrupt_disable( isrlevel ); |
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88 | (void) set_vector( clock_isr, CLOCK_VECTOR, 1 ); |
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89 | rtems_interrupt_enable( isrlevel ); |
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90 | } |
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91 | |
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92 | /* |
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93 | * Install_clock |
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94 | * |
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95 | * Install a clock tick handler and reprograms the chip. This |
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96 | * is used to initially establish the clock tick. |
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97 | */ |
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98 | |
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99 | void Install_clock( |
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100 | rtems_isr_entry clock_isr |
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101 | ) |
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102 | { |
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103 | /* |
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104 | * Initialize the clock tick device driver variables |
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105 | */ |
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106 | |
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107 | Clock_driver_ticks = 0; |
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108 | Clock_isrs = BSP_Configuration.microseconds_per_tick / 1000; |
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109 | |
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110 | /* |
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111 | * If ticks_per_timeslice is configured as non-zero, then the user |
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112 | * wants a clock tick. |
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113 | */ |
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114 | |
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115 | if ( BSP_Configuration.ticks_per_timeslice ) { |
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116 | Old_ticker = ( rtems_isr_entry ) set_vector( clock_isr, CLOCK_VECTOR, 1 ); |
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117 | /* |
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118 | * Hardware specific initialize goes here |
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119 | */ |
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120 | |
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121 | /* XXX */ |
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122 | } |
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123 | |
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124 | /* |
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125 | * Schedule the clock cleanup routine to execute if the application exits. |
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126 | */ |
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127 | |
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128 | atexit( Clock_exit ); |
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129 | } |
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130 | |
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131 | /* |
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132 | * Clean up before the application exits |
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133 | */ |
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134 | |
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135 | void Clock_exit( void ) |
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136 | { |
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137 | if ( BSP_Configuration.ticks_per_timeslice ) { |
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138 | |
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139 | /* XXX: turn off the timer interrupts */ |
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140 | |
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141 | /* XXX: If necessary, restore the old vector */ |
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142 | } |
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143 | } |
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