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NAME="DEVAPI-SYNCHRONIZATION-LEVELS">Synchronization Levels</H1
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>Since it would be dangerous for an ISR or DSR to make a call
that might reschedule the current thread (by trying to lock a mutex
for example) all functions in this API have an associated synchronization
level. These levels are:</P
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> This function may only be called from within threads. This is
usually the client code that makes calls into the device driver.
In a non-kernel configuration, this will be code running at the
default non-interrupt level.
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>DSR</DT
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> This function may be called by either DSR or thread code.
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>ISR</DT
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> This function may be called from ISR, DSR or thread code.
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><P
>The following table shows, for each API function, the levels
at which is may be called:</P
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> Callable from:
Function ISR DSR Thread
-------------------------------------------------------------------------
cyg_drv_isr_lock X X X
cyg_drv_isr_unlock X X X
cyg_drv_spinlock_init X
cyg_drv_spinlock_destroy X
cyg_drv_spinlock_spin X X X
cyg_drv_spinlock_clear X X X
cyg_drv_spinlock_try X X X
cyg_drv_spinlock_test X X X
cyg_drv_spinlock_spin_intsave X X X
cyg_drv_spinlock_clear_intsave X X X
cyg_drv_dsr_lock X X
cyg_drv_dsr_unlock X X
cyg_drv_mutex_init X
cyg_drv_mutex_destroy X
cyg_drv_mutex_lock X
cyg_drv_mutex_trylock X
cyg_drv_mutex_unlock X
cyg_drv_mutex_release X
cyg_drv_cond_init X
cyg_drv_cond_destroy X
cyg_drv_cond_wait X
cyg_drv_cond_signal X X
cyg_drv_cond_broadcast X X
cyg_drv_interrupt_create X
cyg_drv_interrupt_delete X
cyg_drv_interrupt_attach X X X
cyg_drv_interrupt_detach X X X
cyg_drv_interrupt_mask X X X
cyg_drv_interrupt_unmask X X X
cyg_drv_interrupt_acknowledge X X X
cyg_drv_interrupt_configure X X X
cyg_drv_interrupt_level X X X
cyg_drv_interrupt_set_cpu X X X
cyg_drv_interrupt_get_cpu X X X </PRE
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