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view src/gpf/inc/nuc/old/sm_defs.h @ 220:0ed36de51973
ABB semaphore protection overhaul
The ABB semaphone protection logic that came with TCS211 from TI
was broken in several ways:
* Some semaphore-protected functions were called from Application_Initialize()
context. NU_Obtain_Semaphore() called with NU_SUSPEND fails with
NU_INVALID_SUSPEND in this context, but the return value wasn't checked,
and NU_Release_Semaphore() would be called unconditionally at the end.
The latter call would increment the semaphore count past 1, making the
semaphore no longer binary and thus no longer effective for resource
protection. The fix is to check the return value from NU_Obtain_Semaphore()
and skip the NU_Release_Semaphore() call if the semaphore wasn't properly
obtained.
* Some SPI hardware manipulation was being done before entering the semaphore-
protected critical section. The fix is to reorder the code: first obtain
the semaphore, then do everything else.
* In the corner case of L1/DSP recovery, l1_abb_power_on() would call some
non-semaphore-protected ABB & SPI init functions. The fix is to skip those
calls in the case of recovery.
* A few additional corner cases existed, all of which are fixed by making
ABB semaphore protection 100% consistent for all ABB functions and code paths.
There is still one remaining problem of priority inversion: suppose a low-
priority task calls an ABB function, and some medium-priority task just happens
to preempt right in the middle of that semaphore-protected ABB operation. Then
the high-priority SPI task is locked out for a non-deterministic time until
that medium-priority task finishes its work and goes back to sleep. This
priority inversion problem remains outstanding for now.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Mon, 26 Apr 2021 20:55:25 +0000 |
parents | 4e78acac3d88 |
children |
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/*************************************************************************/ /* */ /* Copyright (c) 1993-1996 Accelerated Technology, Inc. */ /* */ /* PROPRIETARY RIGHTS of Accelerated Technology are involved in the */ /* subject matter of this material. All manufacturing, reproduction, */ /* use, and sales rights pertaining to this subject matter are governed */ /* by the license agreement. The recipient of this software implicitly */ /* accepts the terms of the license. */ /* */ /*************************************************************************/ /*************************************************************************/ /* */ /* FILE NAME VERSION */ /* */ /* sm_defs.h PLUS 1.2 */ /* */ /* COMPONENT */ /* */ /* SM - Semaphore Management */ /* */ /* DESCRIPTION */ /* */ /* This file contains data structure definitions and constants for */ /* the Semaphore component. */ /* */ /* AUTHOR */ /* */ /* William E. Lamie, Accelerated Technology, Inc. */ /* */ /* DATA STRUCTURES */ /* */ /* SM_SCB Semaphore control block */ /* SM_SUSPEND Semaphore suspension block */ /* */ /* FUNCTIONS */ /* */ /* None */ /* */ /* DEPENDENCIES */ /* */ /* cs_defs.h Common service definitions */ /* tc_defs.h Thread Control definitions */ /* */ /* HISTORY */ /* */ /* NAME DATE REMARKS */ /* */ /* W. Lamie 03-01-1993 Created initial version 1.0 */ /* D. Lamie 04-19-1993 Verified version 1.0 */ /* W. Lamie 03-01-1994 Moved include files outside of */ /* the file #ifndef to allow the */ /* use of actual data structures, */ /* removed protection structure, */ /* put padding into structure, */ /* resulting in version 1.1 */ /* R. Pfaff - */ /* D. Lamie 03-18-1994 Verified version 1.1 */ /* M.Q. Qian 04-17-1996 updated to version 1.2 */ /* */ /*************************************************************************/ #include "cs_defs.h" /* Common service constants */ #include "tc_defs.h" /* Thread control constants */ /* Check to see if the file has been included already. */ #ifndef SM_DEFS #define SM_DEFS /* Define constants local to this component. */ #define SM_SEMAPHORE_ID 0x53454d41UL /* Define the Semaphore Control Block data type. */ typedef struct SM_SCB_STRUCT { CS_NODE sm_created; /* Node for linking to */ /* created semaphore list */ UNSIGNED sm_id; /* Internal SCB ID */ CHAR sm_name[NU_MAX_NAME]; /* Semaphore name */ UNSIGNED sm_semaphore_count; /* Counting semaphore */ DATA_ELEMENT sm_fifo_suspend; /* Suspension type flag */ #if PAD_1 DATA_ELEMENT sm_padding[PAD_1]; #endif UNSIGNED sm_tasks_waiting; /* Number of waiting tasks*/ struct SM_SUSPEND_STRUCT *sm_suspension_list; /* Suspension list */ } SM_SCB; /* Define the semaphore suspension structure. This structure is allocated off of the caller's stack. */ typedef struct SM_SUSPEND_STRUCT { CS_NODE sm_suspend_link; /* Link to suspend blocks */ SM_SCB *sm_semaphore; /* Pointer to semaphore */ TC_TCB *sm_suspended_task; /* Task suspended */ STATUS sm_return_status; /* Return status */ } SM_SUSPEND; #endif