[acc25ee] | 1 | /* |
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| 2 | * Clock Tick Device Driver |
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| 3 | * |
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| 4 | * This routine utilizes the Decrementer Register common to the PPC family. |
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| 5 | * |
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| 6 | * The tick frequency is directly programmed to the configured number of |
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| 7 | * microseconds per tick. |
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| 8 | * |
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| 9 | * COPYRIGHT (c) 1989-1997. |
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| 10 | * On-Line Applications Research Corporation (OAR). |
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| 11 | * |
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| 12 | * The license and distribution terms for this file may in |
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| 13 | * the file LICENSE in this distribution or at |
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[21e1c44] | 14 | * http://www.rtems.com/license/LICENSE. |
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[acc25ee] | 15 | * |
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| 16 | * Modified to support the MPC750. |
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| 17 | * Modifications Copyright (c) 1999 Eric Valette valette@crf.canon.fr |
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| 18 | * |
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| 19 | * $Id$ |
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| 20 | */ |
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| 21 | |
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[a73a977] | 22 | #include <rtems/system.h> |
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[acc25ee] | 23 | #include <rtems.h> |
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| 24 | #include <rtems/libio.h> |
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| 25 | #include <stdlib.h> /* for atexit() */ |
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| 26 | #include <assert.h> |
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| 27 | #include <libcpu/c_clock.h> |
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[5c76213] | 28 | #include <rtems/bspIo.h> /* for printk() */ |
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[acc25ee] | 29 | |
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[cebb89b] | 30 | extern int BSP_connect_clock_handler (void); |
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| 31 | |
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[acc25ee] | 32 | /* |
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| 33 | * Clock ticks since initialization |
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| 34 | */ |
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| 35 | |
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[66c373bf] | 36 | volatile uint32_t Clock_driver_ticks; |
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[acc25ee] | 37 | |
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| 38 | /* |
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| 39 | * This is the value programmed into the count down timer. |
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| 40 | */ |
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| 41 | |
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[66c373bf] | 42 | uint32_t Clock_Decrementer_value; |
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[acc25ee] | 43 | |
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| 44 | /* |
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| 45 | * These are set by clock driver during its init |
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| 46 | */ |
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| 47 | |
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| 48 | rtems_device_major_number rtems_clock_major = ~0; |
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| 49 | rtems_device_minor_number rtems_clock_minor; |
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| 50 | |
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| 51 | void clockOff(void* unused) |
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| 52 | { |
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[0dd1d44] | 53 | /* |
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| 54 | * Nothing to do as we cannot disable all interrupts and |
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| 55 | * the decrementer interrupt enable is MSR_EE |
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| 56 | */ |
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[acc25ee] | 57 | } |
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| 58 | void clockOn(void* unused) |
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| 59 | { |
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| 60 | PPC_Set_decrementer( Clock_Decrementer_value ); |
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| 61 | } |
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| 62 | |
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[56758965] | 63 | static void clockHandler(void) |
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| 64 | { |
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| 65 | rtems_clock_tick(); |
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| 66 | } |
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| 67 | |
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| 68 | static void (*clock_handler)(void); |
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| 69 | |
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[acc25ee] | 70 | /* |
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| 71 | * Clock_isr |
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| 72 | * |
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| 73 | * This is the clock tick interrupt handler. |
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| 74 | * |
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| 75 | * Input parameters: |
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| 76 | * vector - vector number |
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| 77 | * |
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| 78 | * Output parameters: NONE |
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| 79 | * |
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| 80 | * Return values: NONE |
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| 81 | * |
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| 82 | */ |
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[d3d9ef37] | 83 | void clockIsr(void *unused) |
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[acc25ee] | 84 | { |
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[c984fb3] | 85 | int decr; |
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[acc25ee] | 86 | /* |
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| 87 | * The driver has seen another tick. |
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| 88 | */ |
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[c984fb3] | 89 | do { |
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[cc9073d] | 90 | register uint32_t flags; |
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| 91 | rtems_interrupt_disable(flags); |
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[de5bc21] | 92 | asm volatile ("mfdec %0; add %0, %0, %1; mtdec %0":"=&r"(decr):"r"(Clock_Decrementer_value)); |
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[cc9073d] | 93 | rtems_interrupt_enable(flags); |
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[acc25ee] | 94 | |
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[c984fb3] | 95 | Clock_driver_ticks += 1; |
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[acc25ee] | 96 | |
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[c984fb3] | 97 | /* |
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| 98 | * Real Time Clock counter/timer is set to automatically reload. |
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| 99 | */ |
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[56758965] | 100 | clock_handler(); |
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[c984fb3] | 101 | } while ( decr < 0 ); |
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[acc25ee] | 102 | } |
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| 103 | |
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| 104 | int clockIsOn(void* unused) |
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| 105 | { |
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[66c373bf] | 106 | uint32_t msr_value; |
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[acc25ee] | 107 | |
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| 108 | _CPU_MSR_GET( msr_value ); |
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| 109 | if (msr_value & MSR_EE) return 1; |
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| 110 | return 0; |
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| 111 | } |
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| 112 | |
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| 113 | |
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| 114 | /* |
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| 115 | * Clock_exit |
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| 116 | * |
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| 117 | * This routine allows the clock driver to exit by masking the interrupt and |
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| 118 | * disabling the clock's counter. |
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| 119 | * |
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| 120 | * Input parameters: NONE |
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| 121 | * |
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| 122 | * Output parameters: NONE |
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| 123 | * |
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| 124 | * Return values: NONE |
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| 125 | * |
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| 126 | */ |
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| 127 | |
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| 128 | void Clock_exit( void ) |
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| 129 | { |
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[0dd1d44] | 130 | (void) BSP_disconnect_clock_handler (); |
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[acc25ee] | 131 | } |
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| 132 | |
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| 133 | /* |
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| 134 | * Clock_initialize |
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| 135 | * |
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| 136 | * This routine initializes the clock driver. |
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| 137 | * |
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| 138 | * Input parameters: |
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| 139 | * major - clock device major number |
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| 140 | * minor - clock device minor number |
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| 141 | * parg - pointer to optional device driver arguments |
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| 142 | * |
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| 143 | * Output parameters: NONE |
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| 144 | * |
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| 145 | * Return values: |
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| 146 | * rtems_device_driver status code |
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| 147 | */ |
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| 148 | |
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| 149 | rtems_device_driver Clock_initialize( |
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| 150 | rtems_device_major_number major, |
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| 151 | rtems_device_minor_number minor, |
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| 152 | void *pargp |
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| 153 | ) |
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| 154 | { |
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[95273a6] | 155 | Clock_Decrementer_value = (BSP_bus_frequency/BSP_time_base_divisor)* |
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[8e13ca61] | 156 | (rtems_configuration_get_microseconds_per_tick()/1000); |
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[acc25ee] | 157 | |
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[c984fb3] | 158 | /* set the decrementer now, prior to installing the handler |
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| 159 | * so no interrupts will happen in a while. |
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| 160 | */ |
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| 161 | PPC_Set_decrementer( (unsigned)-1 ); |
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| 162 | |
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| 163 | /* if a decrementer exception was pending, it is cleared by |
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| 164 | * executing the default (nop) handler at this point; |
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| 165 | * The next exception will then be taken by our clock handler. |
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| 166 | * Clock handler installation initializes the decrementer to |
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| 167 | * the correct value. |
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| 168 | */ |
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| 169 | |
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[56758965] | 170 | clock_handler = clockHandler; |
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[acc25ee] | 171 | if (!BSP_connect_clock_handler ()) { |
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| 172 | printk("Unable to initialize system clock\n"); |
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| 173 | rtems_fatal_error_occurred(1); |
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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 | |
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| 177 | rtems_clock_major = major; |
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| 178 | rtems_clock_minor = minor; |
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| 179 | |
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| 180 | return RTEMS_SUCCESSFUL; |
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| 181 | } /* Clock_initialize */ |
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| 182 | |
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| 183 | /* |
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| 184 | * Clock_control |
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| 185 | * |
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| 186 | * This routine is the clock device driver control entry point. |
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| 187 | * |
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| 188 | * Input parameters: |
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| 189 | * major - clock device major number |
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| 190 | * minor - clock device minor number |
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| 191 | * parg - pointer to optional device driver arguments |
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| 192 | * |
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| 193 | * Output parameters: NONE |
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| 194 | * |
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| 195 | * Return values: |
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| 196 | * rtems_device_driver status code |
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| 197 | */ |
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| 198 | |
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| 199 | rtems_device_driver Clock_control( |
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| 200 | rtems_device_major_number major, |
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| 201 | rtems_device_minor_number minor, |
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| 202 | void *pargp |
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| 203 | ) |
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| 204 | { |
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| 205 | rtems_libio_ioctl_args_t *args = pargp; |
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| 206 | |
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| 207 | if (args == 0) |
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| 208 | goto done; |
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| 209 | |
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[95273a6] | 210 | Clock_Decrementer_value = (BSP_bus_frequency/BSP_time_base_divisor)* |
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[8e13ca61] | 211 | (rtems_configuration_get_microseconds_per_tick()/1000); |
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[acc25ee] | 212 | |
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| 213 | if (args->command == rtems_build_name('I', 'S', 'R', ' ')) |
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[56758965] | 214 | clockHandler(); |
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[acc25ee] | 215 | else if (args->command == rtems_build_name('N', 'E', 'W', ' ')) |
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| 216 | { |
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[56758965] | 217 | if (clock_handler == NULL) |
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| 218 | Clock_initialize(major, minor, 0); |
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| 219 | clock_handler = args->buffer; |
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[acc25ee] | 220 | } |
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| 221 | done: |
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| 222 | return RTEMS_SUCCESSFUL; |
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| 223 | } |
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