Gates are used by clients to protect concurrent access to critical data structures. Critical data structures are those that must be updated by at most one thread at a time. All code that needs access to a critical data structure "enters" a gate (that's associated with the data structure) prior to accessing the data, modifies the data structure, then "leaves" the gate.
A gate is responsible for ensuring that at most one thread at a time can enter and execute "inside" the gate. There are several implementations of gates, with different system executation times and latency tradoffs. In addition, some gates must not be entered by certain thread types; e.g., a gate that is implemented via a "blocking" semaphore must not be called by an interrupt service routine (ISR).
A module can be declared "gated" by adding the `` attribute to the module's XDC spec file. A "gated" module is assigned a module-level gate at the configuration time, and that gate is then used to protect critical sections in the module's target code. A module-level gate is an instance of a module implementing `IGateProvider` interface. However, gated modules do not access their module-level gates directly. They use this module to access transparently their module-level gate.
Application code that is not a part of any module also has a module-level gate, configured through the module `Main`.
Each gated module can optionally create gates on an adhoc basis at runtime using the same gate module that was used to create the module level gate.
Gates that work by disabling all preemption while inside a gate can be used to protect data structures accessed by ISRs and other threads. But, if the time required to update the data structure is not a small constant, this type of gate may violate a system's real-time requirements.
Gates have two orthogonal attributes: "blocking" and "preemptible". In general, gates that are "blocking" can not be use by code that is called by ISRs and gates that are not "preemptible" should only be used to to protect data manipulated by code that has small constant execution time.
02.00.00.68_beta1
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Definition in file Gate.h.
#include <ti/syslink/utils/IGateProvider.h>
Include dependency graph for Gate.h:
Go to the source code of this file.
Functions | |
| IArg | Gate_enterSystem (void) |
| Void | Gate_leaveSystem (IArg key) |
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| IGateProvider_Handle | Gate_systemHandle |
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1.4.4