module ti.sysbios.gates.GateMutex

Mutex Gate

GateMutex uses a Semaphore as the resource locking mechanism. Each GateMutex instance has its own unique Semaphore. This gate can only be used by a Task as a gate can potentially block. This gate cannot be used by a Hwi or Swi. [ more ... ]
C synopsis target-domain sourced in ti/sysbios/gates/GateMutex.xdc
#include <ti/sysbios/gates/GateMutex.h>
Functions
Void
Void
Void
Void
Functions common to all IGateProvider modules
IArg 
Void 
Bool 
Functions common to all target instances
Functions common to all target modules
Defines
#define
#define
Typedefs
typedef struct
typedef struct
typedef struct
Constants
extern const Assert_Id 
 
DETAILS
GateMutex uses a Semaphore as the resource locking mechanism. Each GateMutex instance has its own unique Semaphore. This gate can only be used by a Task as a gate can potentially block. This gate cannot be used by a Hwi or Swi.
The task that uses a gate can call enter() any number of times without risk of being blocked, although relinquishing ownership of the gate requires a balanced number of calls to leave().

Calling Context

Function Hwi Swi Task Main Startup
Params_init Y Y Y Y Y
query Y Y Y Y Y
construct N N Y Y N
create N* N* Y Y N
delete N* N* Y Y N
destruct N N Y Y N
enter N N Y N N
leave N N Y N N
Definitions:
  • Hwi: API is callable from a Hwi thread.
  • Swi: API is callable from a Swi thread.
  • Task: API is callable from a Task thread.
  • Main: API is callable during any of these phases:
    • In your module startup after this module is started (e.g. GateMutex_Module_startupDone() returns TRUE).
    • During xdc.runtime.Startup.lastFxns.
    • During main().
    • During BIOS.startupFxns.
  • Startup: API is callable during any of these phases:
    • During xdc.runtime.Startup.firstFxns.
    • In your module startup before this module is started (e.g. GateMutex_Module_startupDone() returns FALSE).
  • *: Assuming blocking Heap is used for creation.
  • **: Must be used in enter/leave pairs.
 
const GateMutex_Q_BLOCKING

Blocking quality

C synopsis target-domain
#define GateMutex_Q_BLOCKING (Int)1
 
DETAILS
Gates with this "quality" may cause the calling thread to block; i.e., suspend execution until another thread leaves the gate.
 
const GateMutex_Q_PREEMPTING

Preempting quality

C synopsis target-domain
#define GateMutex_Q_PREEMPTING (Int)2
 
DETAILS
Gates with this "quality" allow other threads to preempt the thread that has already entered the gate.
 
config GateMutex_A_badContext  // module-wide

Assert when GateMutex_enter() is not called from correct context. GateMutex_enter() can only be called from main() or Task context (not Hwi or Swi)

C synopsis target-domain
extern const Assert_Id GateMutex_A_badContext;
 
DETAILS
Common causes and workarounds for hitting this Assert:
- Calling printf() from a Hwi or Swi thread.
  • Use xdc.runtime.System_printf (with SysMin) instead.
- Calling System_printf() from a Hwi or Swi thread when using SysStd.
- Calling Memory_alloc() from a Hwi or Swi thread.
  • Use a different Heap manager
 
GateMutex_query()  // module-wide

Runtime test for a particular gate quality

C synopsis target-domain
Bool GateMutex_query(Int qual);
 
ARGUMENTS
qual — constant describing a quality
RETURNS
Returns TRUE if the gate has the given quality, and FALSE otherwise, which includes the case when the gate does not recognize the constant describing the quality.
Module-Wide Built-Ins

C synopsis target-domain
Types_ModuleId GateMutex_Module_id();
// Get this module's unique id
 
Bool GateMutex_Module_startupDone();
// Test if this module has completed startup
 
IHeap_Handle GateMutex_Module_heap();
// The heap from which this module allocates memory
 
Bool GateMutex_Module_hasMask();
// Test whether this module has a diagnostics mask
 
Bits16 GateMutex_Module_getMask();
// Returns the diagnostics mask for this module
 
Void GateMutex_Module_setMask(Bits16 mask);
// Set the diagnostics mask for this module
Instance Object Types

C synopsis target-domain
typedef struct GateMutex_Object GateMutex_Object;
// Opaque internal representation of an instance object
 
typedef GateMutex_Object *GateMutex_Handle;
// Client reference to an instance object
 
typedef struct GateMutex_Struct GateMutex_Struct;
// Opaque client structure large enough to hold an instance object
 
GateMutex_Handle GateMutex_handle(GateMutex_Struct *structP);
// Convert this instance structure pointer into an instance handle
 
GateMutex_Struct *GateMutex_struct(GateMutex_Handle handle);
// Convert this instance handle into an instance structure pointer
Instance Config Parameters

C synopsis target-domain
typedef struct GateMutex_Params {
// Instance config-params structure
    IInstance_Params *instance;
    // Common per-instance configs
} GateMutex_Params;
 
Void GateMutex_Params_init(GateMutex_Params *params);
// Initialize this config-params structure with supplier-specified defaults before instance creation
Runtime Instance Creation

C synopsis target-domain
GateMutex_Handle GateMutex_create(const GateMutex_Params *params, Error_Block *eb);
// Allocate and initialize a new instance object and return its handle
 
Void GateMutex_construct(GateMutex_Struct *structP, const GateMutex_Params *params);
// Initialize a new instance object inside the provided structure
ARGUMENTS
params — per-instance config params, or NULL to select default values (target-domain only)
eb — active error-handling block, or NULL to select default policy (target-domain only)
Instance Deletion

C synopsis target-domain
Void GateMutex_delete(GateMutex_Handle *handleP);
// Finalize and free this previously allocated instance object, setting the referenced handle to NULL
 
Void GateMutex_destruct(GateMutex_Struct *structP);
// Finalize the instance object inside the provided structure
 
GateMutex_enter()  // instance

Enter this gate

C synopsis target-domain
IArg GateMutex_enter(GateMutex_Handle handle);
 
ARGUMENTS
handle — handle of a previously-created GateMutex instance object
DETAILS
Each gate provider can implement mutual exclusion using different algorithms; e.g., disabling all scheduling, disabling the scheduling of all threads below a specified "priority level", suspending the caller when the gate has been entered by another thread and re-enabling it when the the other thread leaves the gate. However, in all cases, after this method returns that caller has exclusive access to the data protected by this gate.
A thread may reenter a gate without blocking or failing.
RETURNS
Returns a "key" that is used to leave this gate; this value is used to restore thread preemption to the state that existed just prior to entering this gate.
 
GateMutex_leave()  // instance

Leave this gate

C synopsis target-domain
Void GateMutex_leave(GateMutex_Handle handle, IArg key);
 
ARGUMENTS
handle — handle of a previously-created GateMutex instance object
key — the value returned by a matching call to enter
DETAILS
This method is only called by threads that have previously entered this gate via enter. After this method returns, the caller must not access the data structure protected by this gate (unless the caller has entered the gate more than once and other calls to leave remain to balance the number of previous calls to enter).
Instance Convertors

C synopsis target-domain
IGateProvider_Handle GateMutex_Handle_upCast(GateMutex_Handle handle);
// unconditionally move one level up the inheritance hierarchy
 
GateMutex_Handle GateMutex_Handle_downCast(IGateProvider_Handle handle);
// conditionally move one level down the inheritance hierarchy; NULL upon failure
Instance Built-Ins

C synopsis target-domain
Int GateMutex_Object_count();
// The number of statically-created instance objects
 
GateMutex_Handle GateMutex_Object_get(GateMutex_Object *array, Int i);
// The handle of the i-th statically-created instance object (array == NULL)
 
GateMutex_Handle GateMutex_Object_first();
// The handle of the first dynamically-created instance object, or NULL
 
GateMutex_Handle GateMutex_Object_next(GateMutex_Handle handle);
// The handle of the next dynamically-created instance object, or NULL
 
IHeap_Handle GateMutex_Object_heap();
// The heap used to allocate dynamically-created instance objects
 
Types_Label *GateMutex_Handle_label(GateMutex_Handle handle, Types_Label *buf);
// The label associated with this instance object
 
String GateMutex_Handle_name(GateMutex_Handle handle);
// The name of this instance object
 
Configuration settings sourced in ti/sysbios/gates/GateMutex.xdc
var GateMutex = xdc.useModule('ti.sysbios.gates.GateMutex');
module-wide constants & types
module-wide config parameters
        msg: "A_badContext: bad calling context. See GateMutex API doc for details."
    };
 
module-wide functions
per-instance config parameters
    var params = new GateMutex.Params// Instance config-params object;
per-instance creation
    var inst = GateMutex.create// Create an instance-object(params);
 
 
const GateMutex.Q_BLOCKING

Blocking quality

Configuration settings
const GateMutex.Q_BLOCKING = 1;
 
DETAILS
Gates with this "quality" may cause the calling thread to block; i.e., suspend execution until another thread leaves the gate.
C SYNOPSIS
 
const GateMutex.Q_PREEMPTING

Preempting quality

Configuration settings
const GateMutex.Q_PREEMPTING = 2;
 
DETAILS
Gates with this "quality" allow other threads to preempt the thread that has already entered the gate.
C SYNOPSIS
 
config GateMutex.A_badContext  // module-wide

Assert when GateMutex_enter() is not called from correct context. GateMutex_enter() can only be called from main() or Task context (not Hwi or Swi)

Configuration settings
GateMutex.A_badContext = Assert.Desc {
    msg: "A_badContext: bad calling context. See GateMutex API doc for details."
};
 
DETAILS
Common causes and workarounds for hitting this Assert:
- Calling printf() from a Hwi or Swi thread.
  • Use xdc.runtime.System_printf (with SysMin) instead.
- Calling System_printf() from a Hwi or Swi thread when using SysStd.
- Calling Memory_alloc() from a Hwi or Swi thread.
  • Use a different Heap manager
C SYNOPSIS
 
metaonly config GateMutex.common$  // module-wide

Common module configuration parameters

Configuration settings
GateMutex.common$ = Types.Common$ undefined;
 
DETAILS
All modules have this configuration parameter. Its name contains the '$' character to ensure it does not conflict with configuration parameters declared by the module. This allows new configuration parameters to be added in the future without any chance of breaking existing modules.
 
metaonly GateMutex.queryMeta()  // module-wide

Configuration time test for a particular gate quality

Configuration settings
GateMutex.queryMeta(Int qual) returns Bool
 
ARGUMENTS
qual — constant describing a quality
RETURNS
Returns TRUE if the gate has the given quality, and FALSE otherwise, which includes the case when the gate does not recognize the constant describing the quality.
Instance Config Parameters

Configuration settings
var params = new GateMutex.Params;
// Instance config-params object
Static Instance Creation

Configuration settings
var params = new GateMutex.Params;
// Allocate instance config-params
params.config =   ...
// Assign individual configs
 
var inst = GateMutex.create(params);
// Create an instance-object
ARGUMENTS
params — per-instance config params, or NULL to select default values (target-domain only)
eb — active error-handling block, or NULL to select default policy (target-domain only)
generated on Tue, 14 Feb 2017 19:59:36 GMT