TM4C1294KCPDT: Regarding Mutex create using GateMutex and GateMutexPri based on "Quality"

Iyyappan R

Part Number: TM4C1294KCPDT
Other Parts Discussed in Thread: SYSBIOS

Hi,

We can have BLOCKING or PREEMPTING qualities for mutex.

My question is,

Since quality is for a gate configuration, can I create mutex instances with different quality or I have to use single quality for all mutex instances in my entire application?

For Example,

I want to create the common functions for MutexCreate, MutexEnter, MutexLeave, MutexDelete functions. From these functions I will call either GateMutex or GateMutexPri functions based on a flag.

If the flag is FIFO,

then I want to create the mutex by using "GateMutex_Create" function and I want to set the quality as "BLOCKING".

If the flag is Priority,

I want to create the mutex by using "GateMutexPri_Create" function and I want to set the quality as "BLOCKING".

If the flag is InversionSafe,

I want to create the mutex by using "GateMutexPri_Create" function and I want to set the quality as "PREEMPTING".

Is this possible or not by doing any parameter configuration during params_init() call?

With regards,

Iyyappan.

over 5 years ago

0 ToddMullanix over 5 years ago

TI__Guru* 96960 points

You can make different types of Gates in your application and then upcast them and use the IGateProvider module. For example

#include <xdc/runtime/Error.h>
#include <xdc/runtime/IGateProvider.h>
#include <ti/sysbios/gates/GateMutex.h>
#include <ti/sysbios/gates/GateMutexPri.h>

someTask {
    GateMutex_Params     gmParams;
    GateMutex_Handle     gmHandle;
    GateMutexPri_Params  gmpParams;
    GateMutexPri_Handle  gmpHandle;
    IGateProvider_Handle gateHandle1;
    IGateProvider_Handle gateHandle2;
    IArg                 key1;
    IArg                 key2;

    /* Make a GateMutex instance and upCast. Params are optional here since there are no parameters for this module. */
    GateMutex_Params_init(&gmParams);
    gmHandle = GateMutex_create(&gmParams, Error_IGNORE);
    gateHandle1 = GateMutex_Handle_upCast(gmHandle);

    /* Make a GateMutexPri instance and upCast. Again the params are optional... */
    GateMutexPri_Params_init(&gmpParams);
    gmpHandle = GateMutexPri_create(&gmpParams, Error_IGNORE);
    gateHandle2 = GateMutexPri_Handle_upCast(gmpHandle);

    /* Example of generically using the two different gates */
    key1 = IGateProvider_enter(gateHandle1);
    key2 = IGateProvider_enter(gateHandle2);
    IGateProvider_leave(gateHandle2, key2);
    IGateProvider_leave(gateHandle1, key1);

You can use the IGateProvider module to query the qualities of the gate modules also.

Todd

0 Iyyappan R over 5 years ago in reply to ToddMullanix

Prodigy 50 points

Hi Todd,

Thanks for your reply. I checked with your suggestion. I created the mutex whatever you suggested in the reply.

After creating that I called IGateProvider_query to get the quality. I got always TRUE as the return value even though I passed different qualities to check. To know that I started debugging. When we call IGateProvider_query function it will go to below function only.

This function available in C:\ti\xdctools_3_32_01_22_core\packages\xdc\runtime\IGateProvider.h location.

In this __inst->query is points to the GateMutexPri_query and GateMutex_query only (Refer below).

Location for above two functions

C:\ti\tirtos_tivac_2_16_00_08\products\bios_6_45_01_29\packages\ti\sysbios\gates\GateMutex.c for GateMutex_query function.

C:\ti\tirtos_tivac_2_16_00_08\products\bios_6_45_01_29\packages\ti\sysbios\gates\GateMutexPri.c for GateMutexPri_query function.

These functions will always return TRUE only. I Put the breakpoints in those functions and checked.

If this is the case means how we will get the exact usage of quality?

I am using TI-RTOS version - 2.16 and BIOS version 6.45.

regards,

Iyyappan.

0 ToddMullanix over 5 years ago in reply to Iyyappan R

TI__Guru* 96960 points

Iyyappan,

Both GateMutex and GateMutexPri can "block" the calling task (call it TaskA). By "block", I mean that some other task could have already entered the gate, so TaskA will block on the semaphore in the GateMutex_enter (or GateMutexPri_enter) call.

Similarly with the "preempting" quality. Let a task (call it TaskA again) own the gate (e.g. has successfully returned from GateMutex_enter (or GateMutexPri_enter or IGateProvider_enter)), if a higher priority thread (e.g. Hwi, Swi or higher priority Task) becomes ready to run, that higher priority thread will preempt TaskA.

When are cases where the query returns false? GateHwi disables interrupts in GateHwi_enter. So when the running thread calls GateHwi_enter, it will not block since it is the running task. Once you return from GateHwi_enter, the thread that owns the gate cannot be preempted since all interrupts are disabled (and you should not be making kernel calls that impact the scheduler while you own the gate).

We made the query functions in case you just have a IGateProvider_Handle and need to know more about it before using it.

Todd

0 Iyyappan R over 5 years ago in reply to ToddMullanix

Prodigy 50 points

Hi Todd,

I understand whatever you are saying. But still my doubt is uncleared. My question is "Can we create explicitly two priority mutex instances, one with quality BLOCKING and another with quality PREEMPTIVE?".

regards,

Iyyappan.

0 ToddMullanix over 5 years ago in reply to Iyyappan R

TI__Guru* 96960 points

Hi lyypappan.

No. These are read-only qualities of the GateMutex and GateMutexPri modules.

Todd

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TM4C1294KCPDT: Regarding Mutex create using GateMutex and GateMutexPri based on "Quality"