1 | /** |
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2 | * @file |
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3 | * |
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4 | * @ingroup bsp_clock |
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5 | * |
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6 | * @brief Raspberry Pi clock support. |
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7 | */ |
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8 | |
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9 | /* |
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10 | * BCM2835 Clock driver |
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11 | * |
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12 | * Copyright (c) 2013 Alan Cudmore |
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13 | * |
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14 | * The license and distribution terms for this file may be |
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15 | * found in the file LICENSE in this distribution or at |
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16 | * |
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17 | * http://www.rtems.org/license/LICENSE |
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18 | * |
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19 | */ |
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20 | |
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21 | #include <rtems.h> |
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22 | #include <bsp.h> |
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23 | #include <bsp/irq.h> |
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24 | #include <bsp/raspberrypi.h> |
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25 | |
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26 | /* This is defined in ../../../shared/clockdrv_shell.h */ |
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27 | void Clock_isr(rtems_irq_hdl_param arg); |
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28 | |
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29 | static void raspberrypi_clock_at_tick(void) |
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30 | { |
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31 | BCM2835_REG(BCM2835_TIMER_CLI) = 0; |
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32 | } |
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33 | |
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34 | static void raspberrypi_clock_handler_install(void) |
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35 | { |
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36 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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37 | |
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38 | sc = rtems_interrupt_handler_install( |
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39 | BCM2835_IRQ_ID_TIMER_0, |
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40 | "Clock", |
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41 | RTEMS_INTERRUPT_UNIQUE, |
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42 | (rtems_interrupt_handler) Clock_isr, |
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43 | NULL |
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44 | ); |
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45 | if (sc != RTEMS_SUCCESSFUL) { |
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46 | rtems_fatal_error_occurred(0xdeadbeef); |
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47 | } |
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48 | } |
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49 | |
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50 | static void raspberrypi_clock_initialize(void) |
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51 | { |
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52 | BCM2835_REG(BCM2835_TIMER_CTL) = 0x003E0000; |
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53 | BCM2835_REG(BCM2835_TIMER_LOD) = 10000 - 1; |
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54 | BCM2835_REG(BCM2835_TIMER_RLD) = 10000 - 1; |
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55 | BCM2835_REG(BCM2835_TIMER_DIV) = BCM2835_TIMER_PRESCALE; |
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56 | BCM2835_REG(BCM2835_TIMER_CLI) = 0; |
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57 | BCM2835_REG(BCM2835_TIMER_CTL) = 0x003E00A2; |
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58 | } |
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59 | |
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60 | static void raspberrypi_clock_cleanup(void) |
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61 | { |
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62 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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63 | |
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64 | /* Remove interrupt handler */ |
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65 | sc = rtems_interrupt_handler_remove( |
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66 | BCM2835_IRQ_ID_TIMER_0, |
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67 | (rtems_interrupt_handler) Clock_isr, |
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68 | NULL |
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69 | ); |
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70 | if (sc != RTEMS_SUCCESSFUL) { |
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71 | rtems_fatal_error_occurred(0xdeadbeef); |
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72 | } |
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73 | } |
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74 | |
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75 | /* |
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76 | * Return the nanoseconds since last tick |
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77 | */ |
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78 | static uint32_t raspberrypi_clock_nanoseconds_since_last_tick(void) |
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79 | { |
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80 | return 0; |
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81 | } |
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82 | |
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83 | #define Clock_driver_support_at_tick() raspberrypi_clock_at_tick() |
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84 | |
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85 | #define Clock_driver_support_initialize_hardware() raspberrypi_clock_initialize() |
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86 | |
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87 | #define Clock_driver_support_install_isr(isr, old_isr) \ |
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88 | do { \ |
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89 | raspberrypi_clock_handler_install(); \ |
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90 | old_isr = NULL; \ |
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91 | } while (0) |
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92 | |
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93 | #define Clock_driver_support_shutdown_hardware() raspberrypi_clock_cleanup() |
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94 | |
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95 | #define Clock_driver_nanoseconds_since_last_tick \ |
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96 | raspberrypi_clock_nanoseconds_since_last_tick |
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97 | |
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98 | |
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99 | #include "../../../shared/clockdrv_shell.h" |
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