1 | /* |
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2 | * Clock Driver for MCF5272 CPU |
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3 | * |
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4 | * This driver initailizes timer1 on the MCF5272 as the |
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5 | * main system clock |
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6 | * |
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7 | * Copyright 2004 Cogent Computer Systems |
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8 | * Author: Jay Monkman <jtm@lopingdog.com> |
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9 | * |
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10 | * Based on MCF5206 clock driver by |
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11 | * Victor V. Vengerov <vvv@oktet.ru> |
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12 | * |
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13 | * Based on work: |
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14 | * David Fiddes, D.J@fiddes.surfaid.org |
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15 | * http://www.calm.hw.ac.uk/davidf/coldfire/ |
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16 | * |
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17 | * COPYRIGHT (c) 1989-1998. |
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18 | * On-Line Applications Research Corporation (OAR). |
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19 | * |
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20 | * The license and distribution terms for this file may be |
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21 | * found in the file LICENSE in this distribution or at |
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22 | * http://www.rtems.com/license/LICENSE. |
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23 | */ |
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24 | |
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25 | #include <stdlib.h> |
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26 | #include <bsp.h> |
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27 | #include <rtems/libio.h> |
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28 | #include <mcf5272/mcf5272.h> |
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29 | |
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30 | /* |
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31 | * Clock_driver_ticks is a monotonically increasing counter of the |
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32 | * number of clock ticks since the driver was initialized. |
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33 | */ |
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34 | volatile uint32_t Clock_driver_ticks; |
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35 | |
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36 | |
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37 | /* |
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38 | * These are set by clock driver during its init |
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39 | */ |
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40 | |
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41 | rtems_device_major_number rtems_clock_major = ~0; |
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42 | rtems_device_minor_number rtems_clock_minor; |
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43 | |
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44 | rtems_isr (*rtems_clock_hook)(rtems_vector_number) = NULL; |
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45 | |
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46 | /* Clock_isr -- |
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47 | * This handles the timer interrupt by clearing the timer's interrupt |
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48 | * flag and announcing the clock tick to the system. |
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49 | * |
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50 | * PARAMETERS: |
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51 | * vector - timer interrupt vector number |
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52 | |
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53 | * RETURNS: |
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54 | * none |
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55 | */ |
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56 | rtems_isr |
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57 | Clock_isr (rtems_vector_number vector) |
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58 | { |
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59 | /* Clear pending interrupt... */ |
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60 | g_timer_regs->ter1 = MCF5272_TER_REF | MCF5272_TER_CAP; |
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61 | |
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62 | /* Announce the clock tick */ |
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63 | Clock_driver_ticks++; |
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64 | rtems_clock_tick(); |
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65 | if (rtems_clock_hook != NULL) { |
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66 | rtems_clock_hook(vector); |
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67 | } |
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68 | } |
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69 | |
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70 | |
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71 | /* Clock_exit -- |
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72 | * This shuts down the timer if it was enabled and removes it |
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73 | * from the MCF5206E interrupt mask. |
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74 | * |
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75 | * PARAMETERS: |
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76 | * none |
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77 | * |
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78 | * RETURNS: |
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79 | * none |
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80 | */ |
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81 | void |
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82 | Clock_exit(void) |
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83 | { |
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84 | if (rtems_configuration_get_ticks_per_timeslice()) { |
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85 | uint32_t icr; |
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86 | /* disable all timer1 interrupts */ |
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87 | icr = g_intctrl_regs->icr1; |
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88 | icr = icr & ~(MCF5272_ICR1_TMR1_MASK | MCF5272_ICR1_TMR1_PI); |
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89 | icr |= (MCF5272_ICR1_TMR1_IPL(0) | MCF5272_ICR1_TMR1_PI); |
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90 | g_intctrl_regs->icr1 = icr; |
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91 | |
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92 | /* reset timer1 */ |
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93 | g_timer_regs->tmr1 = MCF5272_TMR_CLK_STOP; |
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94 | |
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95 | /* clear pending */ |
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96 | g_timer_regs->ter1 = MCF5272_TER_REF | MCF5272_TER_CAP; |
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97 | } |
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98 | } |
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99 | |
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100 | |
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101 | /* Install_clock -- |
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102 | * This initialises timer1 with the BSP timeslice config value |
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103 | * as a reference and sets up the interrupt handler for clock ticks. |
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104 | * |
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105 | * PARAMETERS: |
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106 | * clock_isr - clock interrupt handler routine |
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107 | * |
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108 | * RETURNS: |
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109 | * none. |
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110 | */ |
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111 | static void |
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112 | Install_clock(rtems_isr_entry clock_isr) |
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113 | { |
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114 | uint32_t icr; |
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115 | Clock_driver_ticks = 0; |
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116 | if (rtems_configuration_get_ticks_per_timeslice()) { |
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117 | |
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118 | /* Register the interrupt handler */ |
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119 | set_vector(clock_isr, BSP_INTVEC_TMR1, 1); |
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120 | |
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121 | /* Reset timer 1 */ |
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122 | g_timer_regs->tmr1 = MCF5272_TMR_RST; |
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123 | g_timer_regs->tmr1 = MCF5272_TMR_CLK_STOP; |
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124 | g_timer_regs->tmr1 = MCF5272_TMR_RST; |
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125 | g_timer_regs->tcn1 = 0; /* reset counter */ |
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126 | g_timer_regs->ter1 = MCF5272_TER_REF | MCF5272_TER_CAP; |
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127 | |
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128 | /* Set Timer 1 prescaler so that it counts in microseconds */ |
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129 | g_timer_regs->tmr1 = ( |
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130 | ((((BSP_SYSTEM_FREQUENCY / 1000000) - 1) << MCF5272_TMR_PS_SHIFT) | |
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131 | MCF5272_TMR_CE_DISABLE | |
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132 | MCF5272_TMR_ORI | |
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133 | MCF5272_TMR_FRR | |
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134 | MCF5272_TMR_CLK_MSTR | |
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135 | MCF5272_TMR_RST)); |
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136 | |
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137 | /* Set the timer timeout value from the BSP config */ |
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138 | g_timer_regs->trr1 = rtems_configuration_get_microseconds_per_tick() - 1; |
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139 | |
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140 | /* Feed system frequency to the timer */ |
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141 | g_timer_regs->tmr1 |= MCF5272_TMR_CLK_MSTR; |
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142 | |
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143 | /* Configure timer1 interrupts */ |
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144 | icr = g_intctrl_regs->icr1; |
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145 | icr = icr & ~(MCF5272_ICR1_TMR1_MASK | MCF5272_ICR1_TMR1_PI); |
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146 | icr |= (MCF5272_ICR1_TMR1_IPL(BSP_INTLVL_TMR1) | MCF5272_ICR1_TMR1_PI); |
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147 | g_intctrl_regs->icr1 = icr; |
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148 | |
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149 | /* Register the driver exit procedure so we can shutdown */ |
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150 | atexit(Clock_exit); |
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151 | } |
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152 | } |
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153 | |
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154 | |
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155 | /* Clock_initialize -- |
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156 | * This is called to setup the clock driver. It calls the hardware |
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157 | * setup function and make the driver major/minor values available |
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158 | * for other. |
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159 | * |
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160 | * PARAMETERS: |
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161 | * major - clock device major number |
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162 | * minor - clock device minor number |
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163 | * pargp - device driver initialization argument (not used) |
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164 | * |
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165 | * RETURNS: |
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166 | * RTEMS status code |
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167 | */ |
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168 | rtems_device_driver |
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169 | Clock_initialize(rtems_device_major_number major, |
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170 | rtems_device_minor_number minor, |
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171 | void *pargp) |
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172 | { |
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173 | Install_clock (Clock_isr); |
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174 | |
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175 | /* Make major/minor avail to others such as shared memory driver */ |
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176 | rtems_clock_major = major; |
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177 | rtems_clock_minor = minor; |
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178 | |
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179 | return RTEMS_SUCCESSFUL; |
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180 | } |
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