1 | /* clock.c |
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2 | * |
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3 | * This routine initializes the PIT on the MPC8xx. |
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4 | * The tick frequency is specified by the bsp. |
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5 | * |
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6 | * Author: Jay Monkman (jmonkman@frasca.com) |
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7 | * Copyright (C) 1998 by Frasca International, Inc. |
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8 | * |
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9 | * Derived from c/src/lib/libcpu/ppc/ppc403/clock/clock.c: |
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10 | * |
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11 | * Author: Andrew Bray <andy@i-cubed.co.uk> |
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12 | * |
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13 | * COPYRIGHT (c) 1995 by i-cubed ltd. |
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14 | * |
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15 | * To anyone who acknowledges that this file is provided "AS IS" |
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16 | * without any express or implied warranty: |
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17 | * permission to use, copy, modify, and distribute this file |
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18 | * for any purpose is hereby granted without fee, provided that |
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19 | * the above copyright notice and this notice appears in all |
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20 | * copies, and that the name of i-cubed limited not be used in |
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21 | * advertising or publicity pertaining to distribution of the |
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22 | * software without specific, written prior permission. |
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23 | * i-cubed limited makes no representations about the suitability |
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24 | * of this software for any purpose. |
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25 | * |
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26 | * Derived from c/src/lib/libcpu/hppa1_1/clock/clock.c: |
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27 | * |
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28 | * COPYRIGHT (c) 1989-1998. |
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29 | * On-Line Applications Research Corporation (OAR). |
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30 | * |
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31 | * The license and distribution terms for this file may be |
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32 | * found in the file LICENSE in this distribution or at |
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33 | * http://www.rtems.com/license/LICENSE. |
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34 | * |
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35 | * $Id$ |
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36 | */ |
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37 | |
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38 | #include <rtems.h> |
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39 | #include <clockdrv.h> |
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40 | #include <rtems/libio.h> |
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41 | |
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42 | #include <stdlib.h> /* for atexit() */ |
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43 | #include <mpc8260.h> |
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44 | #include <bsp/irq.h> |
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45 | |
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46 | volatile rtems_unsigned32 Clock_driver_ticks; |
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47 | extern int BSP_get_clock_irq_level(); |
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48 | extern int BSP_connect_clock_handler(rtems_isr_entry); |
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49 | extern int BSP_disconnect_clock_handler(); |
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50 | |
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51 | void Clock_exit( void ); |
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52 | |
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53 | rtems_unsigned32 decrementer_value; |
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54 | |
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55 | volatile int ClockInitialised = 0; |
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56 | |
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57 | |
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58 | /* |
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59 | * These are set by clock driver during its init |
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60 | */ |
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61 | |
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62 | rtems_device_major_number rtems_clock_major = ~0; |
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63 | rtems_device_minor_number rtems_clock_minor; |
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64 | |
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65 | /* |
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66 | * ISR Handler |
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67 | */ |
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68 | rtems_isr Clock_isr(rtems_vector_number vector) |
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69 | { |
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70 | int clicks; |
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71 | |
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72 | if( ClockInitialised ) { |
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73 | PPC_Get_decrementer( clicks ); |
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74 | do { |
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75 | clicks += decrementer_value; |
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76 | PPC_Set_decrementer( clicks ); |
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77 | |
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78 | Clock_driver_ticks++; |
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79 | rtems_clock_tick(); |
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80 | } while( clicks < 100 ); |
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81 | } |
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82 | #if 0 |
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83 | m8260.piscr |= M8260_PISCR_PS; |
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84 | Clock_driver_ticks++; |
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85 | rtems_clock_tick(); |
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86 | #endif |
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87 | |
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88 | |
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89 | } |
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90 | |
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91 | void clockOn(void* unused) |
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92 | { |
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93 | |
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94 | decrementer_value = rtems_configuration_get_microseconds_per_tick() * |
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95 | rtems_cpu_configuration_get_clicks_per_usec() - 1; |
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96 | |
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97 | PPC_Set_decrementer( decrementer_value ); |
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98 | Clock_driver_ticks = 0; |
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99 | |
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100 | ClockInitialised = 1; |
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101 | |
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102 | |
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103 | #if 0 |
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104 | unsigned desiredLevel; |
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105 | rtems_unsigned32 pit_value; |
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106 | |
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107 | pit_value = (rtems_configuration_get_microseconds_per_tick() * |
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108 | rtems_cpu_configuration_get_clicks_per_usec()) - 1 ; |
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109 | |
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110 | if (pit_value > 0xffff) { /* pit is only 16 bits long */ |
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111 | rtems_fatal_error_occurred(-1); |
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112 | } |
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113 | m8260.sccr &= ~(1<<24); |
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114 | m8260.pitc = pit_value; |
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115 | |
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116 | desiredLevel = BSP_get_clock_irq_level(); |
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117 | /* set PIT irq level, enable PIT, PIT interrupts */ |
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118 | /* and clear int. status */ |
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119 | m8260.piscr = /*M8260_PISCR_PIRQ(desiredLevel) |*/ |
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120 | M8260_PISCR_PTE | M8260_PISCR_PS | M8260_PISCR_PIE; |
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121 | #endif |
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122 | } |
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123 | /* |
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124 | * Called via atexit() |
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125 | * Remove the clock interrupt handler by setting handler to NULL |
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126 | */ |
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127 | void |
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128 | clockOff(void* unused) |
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129 | { |
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130 | #if 0 |
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131 | /* disable PIT and PIT interrupts */ |
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132 | m8260.piscr &= ~(M8260_PISCR_PTE | M8260_PISCR_PIE); |
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133 | #endif |
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134 | ClockInitialised = 0; |
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135 | } |
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136 | |
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137 | int clockIsOn(void* unused) |
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138 | { |
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139 | return ClockInitialised; |
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140 | #if 0 |
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141 | if (m8260.piscr & M8260_PISCR_PIE) return 1; |
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142 | return 0; |
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143 | #endif |
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144 | |
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145 | } |
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146 | |
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147 | /* |
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148 | * Called via atexit() |
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149 | * Remove the clock interrupt handler by setting handler to NULL |
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150 | */ |
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151 | void |
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152 | Clock_exit(void) |
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153 | { |
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154 | (void) BSP_disconnect_clock_handler (); |
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155 | } |
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156 | |
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157 | void Install_clock(rtems_isr_entry clock_isr) |
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158 | { |
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159 | Clock_driver_ticks = 0; |
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160 | |
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161 | |
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162 | decrementer_value = rtems_configuration_get_microseconds_per_tick() * |
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163 | rtems_cpu_configuration_get_clicks_per_usec() - 1; |
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164 | |
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165 | PPC_Set_decrementer( decrementer_value ); |
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166 | |
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167 | BSP_connect_clock_handler (clock_isr); |
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168 | |
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169 | |
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170 | ClockInitialised = 1; |
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171 | |
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172 | atexit(Clock_exit); |
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173 | |
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174 | } |
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175 | |
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176 | void |
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177 | ReInstall_clock(rtems_isr_entry new_clock_isr) |
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178 | { |
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179 | BSP_connect_clock_handler (new_clock_isr); |
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180 | } |
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181 | |
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182 | |
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183 | rtems_device_driver Clock_initialize( |
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184 | rtems_device_major_number major, |
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185 | rtems_device_minor_number minor, |
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186 | void *pargp |
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187 | ) |
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188 | { |
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189 | Install_clock( Clock_isr ); |
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190 | |
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191 | /* |
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192 | * make major/minor avail to others such as shared memory driver |
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193 | */ |
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194 | |
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195 | rtems_clock_major = major; |
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196 | rtems_clock_minor = minor; |
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197 | |
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198 | return RTEMS_SUCCESSFUL; |
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199 | } |
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200 | |
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201 | rtems_device_driver Clock_control( |
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202 | rtems_device_major_number major, |
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203 | rtems_device_minor_number minor, |
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204 | void *pargp |
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205 | ) |
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206 | { |
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207 | rtems_libio_ioctl_args_t *args = pargp; |
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208 | |
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209 | if (args == 0) |
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210 | goto done; |
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211 | |
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212 | /* |
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213 | * This is hokey, but until we get a defined interface |
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214 | * to do this, it will just be this simple... |
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215 | */ |
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216 | |
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217 | if (args->command == rtems_build_name('I', 'S', 'R', ' ')) { |
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218 | Clock_isr(BSP_PERIODIC_TIMER); |
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219 | } |
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220 | else if (args->command == rtems_build_name('N', 'E', 'W', ' ')) { |
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221 | ReInstall_clock(args->buffer); |
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222 | } |
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223 | |
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224 | done: |
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225 | return RTEMS_SUCCESSFUL; |
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226 | } |
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227 | |
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