1 | /* |
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2 | * Copyright (c) 2011-2012 Sebastian Huber. All rights reserved. |
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3 | * |
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4 | * embedded brains GmbH |
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5 | * Obere Lagerstr. 30 |
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6 | * 82178 Puchheim |
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7 | * Germany |
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8 | * <rtems@embedded-brains.de> |
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9 | * |
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10 | * The license and distribution terms for this file may be |
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11 | * found in the file LICENSE in this distribution or at |
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12 | * http://www.rtems.com/license/LICENSE. |
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13 | */ |
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14 | |
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15 | #include <rtems.h> |
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16 | #include <rtems/score/armv7m.h> |
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17 | |
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18 | #include <bsp.h> |
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19 | |
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20 | #ifdef ARM_MULTILIB_ARCH_V7M |
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21 | |
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22 | /* This is defined in clockdrv_shell.h */ |
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23 | rtems_isr Clock_isr(rtems_vector_number vector); |
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24 | |
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25 | #define _ARMV7M_Systick_get_factor(freq) \ |
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26 | ((1000000000ULL << 32) / (freq)) |
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27 | |
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28 | #ifdef BSP_ARMV7M_SYSTICK_FREQUENCY |
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29 | #define _ARMV7M_Systick_factor \ |
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30 | _ARMV7M_Systick_get_factor(BSP_ARMV7M_SYSTICK_FREQUENCY) |
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31 | #else |
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32 | static uint64_t _ARMV7M_Systick_factor; |
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33 | #endif |
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34 | |
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35 | static void _ARMV7M_Systick_at_tick(void) |
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36 | { |
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37 | volatile ARMV7M_Systick *systick = _ARMV7M_Systick; |
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38 | |
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39 | /* Clear COUNTFLAG */ |
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40 | systick->csr; |
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41 | } |
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42 | |
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43 | static void _ARMV7M_Systick_handler(void) |
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44 | { |
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45 | _ARMV7M_Interrupt_service_enter(); |
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46 | Clock_isr(ARMV7M_VECTOR_SYSTICK); |
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47 | _ARMV7M_Interrupt_service_leave(); |
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48 | } |
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49 | |
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50 | static void _ARMV7M_Systick_handler_install(void) |
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51 | { |
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52 | _ARMV7M_Set_exception_priority( |
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53 | ARMV7M_VECTOR_SYSTICK, |
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54 | ARMV7M_EXCEPTION_PRIORITY_LOWEST |
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55 | ); |
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56 | _ARMV7M_Set_exception_handler( |
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57 | ARMV7M_VECTOR_SYSTICK, |
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58 | _ARMV7M_Systick_handler |
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59 | ); |
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60 | } |
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61 | |
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62 | static void _ARMV7M_Systick_initialize(void) |
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63 | { |
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64 | volatile ARMV7M_Systick *systick = _ARMV7M_Systick; |
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65 | #ifdef BSP_ARMV7M_SYSTICK_FREQUENCY |
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66 | uint64_t freq = BSP_ARMV7M_SYSTICK_FREQUENCY; |
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67 | #else |
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68 | uint64_t freq = ARMV7M_SYSTICK_CALIB_TENMS_GET(systick->calib) * 100ULL; |
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69 | #endif |
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70 | uint64_t us_per_tick = rtems_configuration_get_microseconds_per_tick(); |
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71 | uint64_t interval = (freq * us_per_tick) / 1000000ULL; |
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72 | |
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73 | #ifndef BSP_ARMV7M_SYSTICK_FREQUENCY |
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74 | _ARMV7M_Systick_factor = _ARMV7M_Systick_get_factor(freq); |
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75 | #endif |
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76 | |
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77 | systick->rvr = (uint32_t) interval; |
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78 | systick->cvr = 0; |
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79 | systick->csr = ARMV7M_SYSTICK_CSR_ENABLE |
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80 | | ARMV7M_SYSTICK_CSR_TICKINT |
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81 | | ARMV7M_SYSTICK_CSR_CLKSOURCE; |
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82 | } |
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83 | |
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84 | static void _ARMV7M_Systick_cleanup(void) |
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85 | { |
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86 | volatile ARMV7M_Systick *systick = _ARMV7M_Systick; |
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87 | |
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88 | systick->csr = 0; |
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89 | } |
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90 | |
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91 | static uint32_t _ARMV7M_Systick_nanoseconds_since_last_tick(void) |
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92 | { |
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93 | volatile ARMV7M_Systick *systick = _ARMV7M_Systick; |
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94 | volatile ARMV7M_SCB *scb = _ARMV7M_SCB; |
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95 | uint32_t rvr = systick->rvr; |
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96 | uint32_t c = rvr - systick->cvr; |
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97 | |
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98 | if ((scb->icsr & ARMV7M_SCB_ICSR_PENDSTSET) != 0) { |
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99 | c = rvr - systick->cvr + rvr; |
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100 | } |
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101 | |
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102 | return (uint32_t) ((c * _ARMV7M_Systick_factor) >> 32); |
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103 | } |
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104 | |
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105 | #define Clock_driver_support_at_tick() \ |
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106 | _ARMV7M_Systick_at_tick() |
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107 | |
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108 | #define Clock_driver_support_initialize_hardware() \ |
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109 | _ARMV7M_Systick_initialize() |
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110 | |
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111 | #define Clock_driver_support_install_isr(isr, old_isr) \ |
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112 | do { \ |
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113 | _ARMV7M_Systick_handler_install(); \ |
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114 | old_isr = NULL; \ |
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115 | } while (0) |
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116 | |
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117 | #define Clock_driver_support_shutdown_hardware() \ |
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118 | _ARMV7M_Systick_cleanup() |
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119 | |
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120 | #define Clock_driver_nanoseconds_since_last_tick \ |
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121 | _ARMV7M_Systick_nanoseconds_since_last_tick |
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122 | |
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123 | /* Include shared source clock driver code */ |
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124 | #include "../../../../shared/clockdrv_shell.h" |
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125 | |
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126 | #endif /* ARM_MULTILIB_ARCH_V7M */ |
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