doc/html/ref/devapi-synchronization-levels.html

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  65 >Chapter 18. Device Driver Interface to the Kernel</TD
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  84 ><A
  85 NAME="DEVAPI-SYNCHRONIZATION-LEVELS">Synchronization Levels</H1
  86 ><P
  87 >Since it would be dangerous for an ISR or DSR to make a call
  88 that might reschedule the current thread (by trying to lock a mutex
  89 for example) all functions in this API have an associated synchronization
  90 level. These levels are:</P
  91 ><P
  92 ></P
  93 ><DIV
  94 CLASS="VARIABLELIST"
  95 ><DL
  96 ><DT
  97 >Thread</DT
  98 ><DD
  99 ><P
 100 >      This function may only be called from within threads. This is
 101       usually the client code that makes calls into the device driver.
 102       In a non-kernel configuration, this will be code running at the
 103       default non-interrupt level.
 104       </P
 105 ></DD
 106 ><DT
 107 >DSR</DT
 108 ><DD
 109 ><P
 110 >      This function may be called by either DSR or thread code.
 111       </P
 112 ></DD
 113 ><DT
 114 >ISR</DT
 115 ><DD
 116 ><P
 117 >      This function may be called from ISR, DSR or thread code.
 118       </P
 119 ></DD
 120 ></DL
 121 ></DIV
 122 ><P
 123 >The following table shows, for each API function, the levels
 124 at which is may be called:</P
 125 ><TABLE
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 129 ><TR
 130 ><TD
 131 ><PRE
 132 CLASS="PROGRAMLISTING"
 133 >                                  Callable from:
 134 Function                       ISR     DSR    Thread
 135 -------------------------------------------------------------------------
 136
 137 cyg_drv_isr_lock                X       X       X
 138 cyg_drv_isr_unlock              X       X       X
 139 cyg_drv_spinlock_init                           X
 140 cyg_drv_spinlock_destroy                        X
 141 cyg_drv_spinlock_spin           X       X       X
 142 cyg_drv_spinlock_clear          X       X       X
 143 cyg_drv_spinlock_try            X       X       X
 144 cyg_drv_spinlock_test           X       X       X
 145 cyg_drv_spinlock_spin_intsave   X       X       X
 146 cyg_drv_spinlock_clear_intsave  X       X       X
 147 cyg_drv_dsr_lock                        X       X
 148 cyg_drv_dsr_unlock                      X       X
 149 cyg_drv_mutex_init                              X
 150 cyg_drv_mutex_destroy                           X
 151 cyg_drv_mutex_lock                              X
 152 cyg_drv_mutex_trylock                           X
 153 cyg_drv_mutex_unlock                            X
 154 cyg_drv_mutex_release                           X
 155 cyg_drv_cond_init                               X
 156 cyg_drv_cond_destroy                            X
 157 cyg_drv_cond_wait                               X
 158 cyg_drv_cond_signal                     X       X
 159 cyg_drv_cond_broadcast                  X       X
 160 cyg_drv_interrupt_create                        X
 161 cyg_drv_interrupt_delete                        X
 162 cyg_drv_interrupt_attach        X       X       X
 163 cyg_drv_interrupt_detach        X       X       X
 164 cyg_drv_interrupt_mask          X       X       X
 165 cyg_drv_interrupt_unmask        X       X       X
 166 cyg_drv_interrupt_acknowledge   X       X       X
 167 cyg_drv_interrupt_configure     X       X       X
 168 cyg_drv_interrupt_level         X       X       X
 169 cyg_drv_interrupt_set_cpu       X       X       X
 170 cyg_drv_interrupt_get_cpu       X       X       X&#13;</PRE
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