FreeCalypso > hg > fc-tourmaline
view src/g23m-fad/ppp/ppp_prxf.c @ 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 | fa8dc04885d8 |
children |
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/* +----------------------------------------------------------------------------- | Project : | Modul : +----------------------------------------------------------------------------- | Copyright 2002 Texas Instruments Berlin, AG | All rights reserved. | | This file is confidential and a trade secret of Texas | Instruments Berlin, AG | The receipt of or possession of this file does not convey | any rights to reproduce or disclose its contents or to | manufacture, use, or sell anything it may describe, in | whole, or in part, without the specific written consent of | Texas Instruments Berlin, AG. +----------------------------------------------------------------------------- | Purpose : This modul is part of the entity PPP and implements all | procedures and functions as described in the | SDL-documentation (PRX-statemachine) +----------------------------------------------------------------------------- */ #define ENTITY_PPP /*==== INCLUDES =============================================================*/ #include "typedefs.h" /* to get Condat data types */ #include "vsi.h" /* to get a lot of macros */ #include "macdef.h" /* to get a lot of macros */ #include "custom.h" /* to get a lot of macros */ /*lint -efile(766,gsm.h) */ #include "gsm.h" /* to get a lot of macros */ /*lint -efile(766,cnf_ppp.h) */ #include "cnf_ppp.h" /* to get cnf-definitions */ /*lint -efile(766,mon_ppp.h) */ #include "mon_ppp.h" /* to get mon-definitions */ #include "prim.h" /* to get the definitions of used SAP and directions */ #include "dti.h" /* to get the DTILIB definitions */ #include "ppp.h" /* to get the global entity definitions */ #ifdef FF_STATUS_TE #include "gdi.h" /* To include driver type-defines */ #include "ste.h" /* To include function interface for TE status driver */ #include "ppp_prxf.h" /* To include call-back function for TE status driver */ #endif /* FF_STATUS_TE */ /*==== CONST ================================================================*/ /*==== LOCAL VARS ===========================================================*/ /*==== PRIVATE FUNCTIONS ====================================================*/ /*==== PUBLIC FUNCTIONS =====================================================*/ /* +------------------------------------------------------------------------------ | Function : prx_init +------------------------------------------------------------------------------ | Description : The function prx_init() initializes Packet Receive (PRX) | | Parameters : no parameters | +------------------------------------------------------------------------------ */ GLOBAL void prx_init () { TRACE_FUNCTION( "prx_init" ); #if defined FF_STATUS_TE /* * Init of the TE status driver - the handle is unique inside PPP only, SMN * PPP handle-management are placed in the end of ppp.h */ if (DRV_OK NEQ STE_Init( STE_HANDLE, cb_status_TE )) { /* * Error during init of TE status driver - either it is already init or it has failed */ TRACE_ERROR( "STE driver init. error" ); } else { #ifdef _SIMULATION_ TRACE_EVENT( "Return DRV_OK from STE_Init()" ); #endif /* _SIMULATION_ */ /* * Setup of used signal-types for driver to trig a callback */ if (DRV_OK NEQ STE_SetSignal( DRV_SIGTYPE_READ )) { /* * Error during signal-set - either signal illegal, not available or internal fail */ TRACE_ERROR( "STE driver setup error" ); } #ifdef _SIMULATION_ else { TRACE_EVENT( "Return DRV_OK from STE_SetSignal()" ); } #endif /* _SIMULATION_ */ } /* * initialize variables */ ppp_data->prx.TE_data_buffer_desc_list_first = NULL; ppp_data->prx.TE_data_buffer_p_id = DTI_PID_UOS; ppp_data->prx.TE_data_buffered = FALSE; #endif /* FF_STATUS_TE */ INIT_STATE( PPP_SERVICE_PRX , PRX_DEAD ); } /* prx_init() */ #ifdef FF_STATUS_TE /* +------------------------------------------------------------------------------ | Function : cb_status_TE +------------------------------------------------------------------------------ | Description : Handles the call-back from the TE status driver and sends the | NEW_POWER_STATUS signal to the PS | | Parameters : None | +------------------------------------------------------------------------------ */ GLOBAL void cb_status_TE (T_DRV_SIGNAL * signal) { TRACE_FUNCTION( "cb_status_TE" ); if((signal->SignalType EQ DRV_SIGTYPE_READ) && (signal->DrvHandle EQ STE_HANDLE) && (*((USHORT*)signal->UserData) EQ STE_IDENTIFIER_POWER)) { PSIGNAL(hCommPPP, NEW_POWER_STATUS, NULL); } else { TRACE_ERROR( "STE driver: Signal not supported" ); } } /* cb_status_TE() */ #endif /* FF_STATUS_TE */